INTRODUCTION — Although patient safety in the operating room (OR) has improved in the last decades, significant risks remain [1]. Adverse events that may occur include those that are subtle and delayed (eg, a central line-associated bloodstream infection) or dramatic and immediate (eg, a fire). Human errors and/or communication failures cause or contribute to most adverse events. Thus, well-designed systems must be in place to prevent and detect errors and reduce harm when a mistake occurs.
Safety issues also exist for the clinicians caring for patients in the OR (eg, infection risk due to contact, droplet exposure, or needle stick injury).
This topic reviews approaches to reduce risk for various hazards to improve patient and provider safety in the OR and other settings where interventional procedures are performed. Details regarding safety in labor and delivery settings are available in a separate topic. (See "Reducing adverse obstetric outcomes through safety sciences".)
HUMAN ERROR: TYPES AND PREVENTION — The science of safety is based on the premise that everyone makes errors which may result in adverse outcomes. Studies have noted that more than one-half of perioperative adverse events were due to errors and were probably preventable [2-4]. Specific processes can be implemented to prevent errors in execution, planning, or problem solving, as well as poor communication, inadequate teamwork, and rules violations, and to minimize the adverse impact of such errors [4-6].
By definition, errors are unintentional; they involve the use of a flawed decision or plan to achieve an aim, or the failure to carry out a planned action as intended. Many are due to inherent cognitive processes, which may lead to action-based or decision-based errors, as noted below [7,8]. Since cognitive processes are similar in all humans, situations leading an individual to make an error are likely to result in repeated errors made by others. Notably, many so-called cognitive errors are actually violations, when the clinician willfully deviates from a practice accepted to be optimal. Such violations are generally not malevolent (the clinician does not intend harm), but occur due to perceived convenience or an attempt to increase productivity (eg, not performing appropriate hand hygiene). Other errors occur due to technical problems or communication failures [2,9,10].
Specific types of errors and general prevention strategies are noted below:
●Action-based (fast thinking) errors – Action-based (ie, skill-based) errors involve thinking that is immediate, associative, unconscious, and effortless (often involving familiar "rules") [11-13]. Examples include:
•Interruption in an often performed sequence of actions (or "schema"), such that a step is skipped or repeated erroneously (eg, forgetting the second dilution in a "double-dilution," of a vasopressor)
•Application of a good rule in the wrong situation (administering atropine to treat a bradyarrhythmia caused by electrocautery interference with pacemaker function)
•Error in pattern matching (chest pain assumed to be due to myocardial infarction when the cause is dissection of an aortic aneurysm)
Prevention of action-based errors involves a brief conscious effort to check that the planned action is the correct one and verify the expected outcome after the action (ie, stop, think, act, and reflect [Star]). Specific strategies include:
•Pausing briefly when performing a schema to verify the steps
•Avoiding distractions during critical tasks
•Implementing evidence-based clinical practice guidelines
•Standardizing techniques so that deviation from the expected result is more easily recognized
•Building redundancy into systems (eg, two person checks)
●Decision-based errors (slow thinking) errors – Decision-based errors involve thinking that is slow, reflective, deductive, conscious, effortful, and logical [11-13]. These may occur when the presenting facts match no recognizable pattern or when no "schema," fits the situation. Errors in these contexts are due to faulty knowledge or judgement. They are more insidious and difficult to identify and correct than action-based errors [14,15]. Critical thinking failure and cognitive biases may lead to inadequate risk assessment, incorrect diagnosis, and/or incorrect choices of treatment [15,16]. Such errors often occur during a crisis, and may be compounded by persistence on an incorrect path.
Prevention of decision-based errors involves improving awareness and insight into cognitive biases and increase consideration of alternative possibilities [17]. Specific strategies include:
•Simulation training to develop "cognitive walkthrough," strategies for specific clinical scenarios. Such training can develop a pattern or rule for even rare and seldom encountered events. (See 'Simulation training' below.)
•Cognitive aids to decrease reliance on memory of "rules," through mnemonics, algorithms, and computerized decision support. Such aids may be particularly important during emergencies and can provide guidance for situations which otherwise would require "thinking from first principles." (See "Cognitive aids for perioperative emergencies".)
•Implementation of evidence-based clinical practice guidelines. (See 'Implementation of evidence-based best practices' below.)
●Technical errors – Technical errors typically occur when the difficulty of the task exceeds the clinician's proficiency, or when the patient’s anatomy is abnormal and complex [2,9,10]. Examples include placing a needle in the carotid artery instead of the internal jugular vein or intubating the esophagus instead of the trachea or intubating the esophagus.
Preventing or minimizing technical errors involves:
•Implementing known safety precautions for skill-based tasks (eg, use of ultrasound guidance for central line placement, use of end-tidal carbon dioxide [ETCO2] to verify endotracheal intubation).
•Building redundancy into systems (eg, two person checks, use of both ultrasound guidance and transduction of a waveform from an 18 gauge needle or catheter that is inserted into a central vein prior to insertion of a larger 8.5 F introducer sheath).
•Conscious evaluation of the complexity of the task and one's own proficiency and inviting a "second pair of hands," if additional proficiency or expertise would be beneficial.
●Communication-based errors – Communication errors resulting in an unintended act are the leading root cause of serious adverse events that result in patient harm (eg, retained surgical items (see "Retained surgical sponge (gossypiboma) and other retained surgical items: Prevention and management", section on 'Work environment')) [15,18-27]. In one study, nearly one-third of all OR communications resulted in partial failure (eg, poor timing, missing or inaccurate content, wrong audience, ineffective communication resulting in failure to resolve the issue) [21]. In another study, ineffective communication was a contributing factor in two-thirds of 50 anonymous reports of critical incidents involving anesthesiologists [15].
Prevention of errors based on poor communication includes the following strategies:
•Use of a preoperative briefing. (See 'Briefings' below.)
•Use of structured communication. (See 'Structured communication' below.)
•Teamwork training to teach communication skills [28-38]. (See 'Team training' below.)
GENERAL APPROACHES TO RISK REDUCTION — General approaches to risk reduction during surgery and other interventional procedures include review of the patient's informed consent, use of timeouts, surgeon-led briefings and team debriefings, standardized checklists for routine cases and cognitive aids during emergencies, techniques to minimize distractions and disruptions, structured communication, and formal handoff procedures during transitions of care.
Reviews of informed consent — Initial review of the surgical consent occurs in the preoperative holding area. This critical part of preparation confirms the patient's identity and their understanding of the specific surgical or interventional procedure to be performed, as well as the site and side of the planned procedure. A 2020 systematic review noted that communication about postoperative care (eg, possible adverse postoperative events, shared decision-making) between patients and anesthesia professionals was rare (3.6 percent of 1284 consultations) was rare even though most patients preferred to be informed of all important aspects of perioperative care [39]. (See 'Wrong procedure or wrong site' below.)
Details for obtaining appropriate informed consent are discussed separately. (See "Preoperative evaluation for anesthesia for noncardiac surgery", section on 'Consent and decision making' and "Informed procedural consent".)
Timeouts — The initial timeout process begins in the preoperative holding area (table 1). Documents are checked to prevent errors by verifying patient identity using dual identifiers, as well as verifying the procedure, side, site, and/or level (see 'Wrong procedure or wrong site' below). This preoperative timeout process should include:
●Participation of the patient or a surrogate to verify identifying information
●Participation of at least two medical professionals
●Documentation in the chart
If a regional block is planned, a separate timeout is necessary just before beginning the process of placing the block. Wrong-side blocks occur as frequently as wrong-side surgical procedures [40-42].
Just before surgical incision, a final brief (less than one minute) timeout is performed with participation of the entire OR team [43]. The patient's identity with dual identifiers, surgical procedure to be performed, and surgical site, side, or level are carefully confirmed in this final timeout.
Briefings — Before surgery, a surgeon-led preoperative briefing or "huddle," that goes beyond a simple checklist should also be performed to ensure thorough communication among all members of the team before beginning a procedure. The World Health Organization (WHO) surgical safety checklist incorporates such a briefing (table 2). Briefings accomplish the following goals [44-49]:
●Development of a shared mental model of the surgical plan and procedures [50]
●Anticipation of risks
●Reduction of trips to retrieve missing equipment
●Completion of all critical steps
●Improvement in teamwork and safety
Standardized preoperative briefings include participation of the entire OR team (surgeon, anesthesiologist, circulating nurse, and scrub technician) and have the following elements (table 2):
●Introducing each team member and their role.
●Rechecking patient identity (using dual identifiers) and consent, the surgical procedure to be performed, and the site, side, or level of surgery (table 1).
●Identifying the patient's medical status (table 3), recent laboratory and/or radiology results, and the management plan for medical comorbidities such as diabetes.
●Ensuring team understanding of goals and critical steps for the procedure, as well as contingency plans.
●Discussing antibiotic administration (if appropriate), including antibiotic selection, initial dosing and timing (table 4), and plans for re-dosing (if appropriate). (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Antibiotic administration'.)
●Discussing venous thrombosis prophylaxis (if appropriate) (table 5). (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)
●Evaluating fire risk and discussing mitigation strategies (eg, reduction of fraction of inspired oxygen [FiO2]). (See "Fire safety in the operating room".)
●Verifying blood product availability (if appropriate). (See "Perioperative blood management: Strategies to minimize transfusions".)
●Determining ideal monitoring strategies and availability of equipment.
●Verifying availability and proper functioning of all necessary surgical equipment and instruments, and identifying any implant concerns.
●Discussing appropriate patient positioning, padding, and skin preparation. (See "Patient positioning for surgery and anesthesia in adults".)
●Planning postoperative disposition (eg, post-anesthesia care unit [PACU] or intensive care unit [ICU]).
●Inviting all team members to ask questions and to speak up regarding any concerns before or during the procedure [51].
Data suggest that briefings result in better patient outcomes and improved staff performance. In one Veterans Administration (VA) study that included more than 180,000 surgical procedures in the years 2006 to 2008, team training in use of briefings, debriefings, and checklists at 74 VA facilities reduced annual mortality by 18 percent compared with a 7 percent reduction during this time period at 34 VA facilities that did not implement training [52]. Other studies have documented improvements in team compliance with best practices after implementation of briefings (eg, antibiotic and deep venous thrombosis prophylaxis) [47,49,53].
Checklists — Checklists ensure that no steps of a procedure are missed. Examples include:
●Standardized surgical team checklist – A standardized checklist such as the World Health Organization (WHO) surgical safety checklist should be used in the OR before starting any surgical or other interventional case [54]. The WHO checklist provides a set of elements to be checked at three stages of any surgical procedure (sign in, timeout, and sign out) (table 2). An appropriate checklist is ideally included as part of a surgeon-led briefing. (See 'Briefings' above.)
A 2018 international meta-analysis of 11 observational studies that included more than 450,000 patients noted that use of the WHO checklist was associated with reduced postoperative mortality (odds ratio [OR] 0.75, 95% CI 0.62-0.92) and complication rates (OR 0.73 (0.61-0.88), compared with no checklist use [55]. Previous systematic reviews noted similar findings [56,57]. Some studies included in these meta-analyses emphasized adherence to all aspects of care embedded in the checklist. Benefits of a checklist depend on relevant design and content, adequate introduction and training, appropriate implementation, and enthusiastic adoption by the surgical team, as well as full compliance with its use [58-60]. The adaptive work of the team may be the critical factor that generates measurable improvements [58]. Partial use or poor implementation of use of a checklist may yield only limited or short-term improvements [55,61,62].
●Standardized anesthesia machine checkout – Another checklist routinely used in the intraoperative setting is the anesthesia machine checkout performed by the anesthesia provider (table 6). Meticulous adherence to published guidelines for pre-use checkout of the anesthesia machine and equipment would likely avoid most critical incidents related to anesthesia workstation misuse or failure, as discussed separately. (See "Anesthesia machines: Prevention, diagnosis, and management of malfunctions", section on 'Standardized anesthesia machine checkout' and 'Equipment errors' below.)
●Cognitive aids for emergencies - Cognitive aids for emergency situations are another type of checklist. These should be immediately available in the OR and other interventional suites, as discussed separately. (See "Cognitive aids for perioperative emergencies".)
Techniques to minimize distractions and disruptions — Distractions occur frequently during surgery (typically 11 to 12 events per hour) [63,64]. For example, equipment alarms occurred at a rate of 1.2 per minute in one cardiac surgical study [65]. In addition to alarms, conversation and even music can disrupt surgical flow and create excessive noise levels interfering with communication [66]. Door openings into the OR are distracting for some clinicians. In one study, this occurred more than 30 times during each hour [67,68]. Another cause of distraction is concentration on untangling multiple intravenous (IV) tubing lines, monitoring wires, and cables connected to the patient [69].
Flow disruptions and distractions cause technical errors that have been associated with adverse events and mortality [70-73]. Evidence suggests that the accumulation of minor events decreases the surgical team's ability to compensate for a major event [74].
Specific techniques to minimize distractions include:
●Limiting the number of individuals in the room. Each additional person increases the number of potential distractions due to door openings and additional conversation, and also increases the bacterial count in the OR [67,68,75].
●Being cognizant of mental workload of each team member. This workload typically varies across time according the clinician’s discipline [76]. For example:
•Anesthesiologists benefit if noise and distractions are limited during induction of general anesthesia.
•Surgeons benefit if interruptions are limited to only those that are critical. Questions about cases for the following day can wait until the end of this procedure.
•Nurses and technicians benefit from minimizing distraction, multitasking, and time pressure during performance of their critical activities (eg, searching for a missing sponge, counting protocols) — (See "Retained surgical sponge (gossypiboma) and other retained surgical items: Prevention and management", section on 'Standardized count protocols' and "Retained surgical sponge (gossypiboma) and other retained surgical items: Prevention and management", section on 'Count discrepancies'.)
●Reducing noise level from all sources (eg, limiting conversations, silencing noncritical alarms, ensuring only soft [or absent] music, turning all beepers to vibrate instead of ring mode [with one team member assigned to manage all pages]).
Notably, auditory cues that are less loud may be helpful. For example, an auditory pulse oximetry display enhanced with tremolo and brightness allowed more accurate detection of values outside the target range [77].
Structured communication — Structured communication is used in other high-risk industries (eg, nuclear power, aviation, military operations), and is often used in the OR, particularly during complex surgical cases or crisis situations [21,78-81]. Structured communication includes:
●Identification of the intended recipient by beginning a communication with the individual's name.
●Use of closed loop communication (ie, speak-back or call-back) by requiring the receiver to repeat the message as heard, after which the sender verifies accuracy.
●Use of standardized words (eg, alpha, bravo, Charlie) and numbers (eg, "one one" for eleven since pronunciation of eleven sounds similar to seven).
Debriefings — After surgery, a postoperative debriefing is used to ensure that all steps were completed, as well as to identify underappreciated hazards, learn from mistakes that occurred during the case, and suggest improvements [46,48,49,82,83]. Identification of errors and near-misses during a debriefing are useful to implement improvements that reduce risk (see 'Establishing safety culture' below) [84].
Specific debriefing tasks include:
●Completion and sign off of sponge/equipment counts (see "Retained surgical sponge (gossypiboma) and other retained surgical items: Prevention and management", section on 'Standardized count protocols')
●Completion of all paperwork, with proper labeling that includes patient name and medical record number
●Completion of specimen forms for pathology
●Discussion of transition from the OR to the PACU or ICU or preparation of patient instructions for patients who are returning home on the day of surgery
●Discussion of any equipment problems that were identified and completion of reports for further investigation
●Discussion of any errors made and identification of possible processes to improve safety or efficiency
Handoffs — Formal standardized handoff protocols, including both verbal and written communication, are used during transfer of patient care from one individual or team to another (either in the OR or after transport from OR to the PACU or ICU). Further discussion is available in separate topics. (See "Handoffs of surgical patients" and "Patient handoffs".)
RISK REDUCTION STRATEGIES FOR SPECIFIC HAZARDS
Wrong procedure or wrong site
●General considerations – In the United States, wrong-site surgery was the second most frequently reported serious adverse event in the period from 1995 to 2005 (12.8 percent of all events in hospitalized patients) in the Joint Commission Sentinel Event statistics database [85]. The percentage of wrong-site surgery events has remained essentially unchanged for nearly two decades (1072 of 8275 sentinel events [12.9 percent] from 2004 to 2014; 336 of 2563 reported events [13.1 percent] from 2015 to 2017). The incidence of these events varied among institutions (0.09 to 4.5 per 10,000 surgical procedures) [85]. Notably, equal numbers of wrong site events occur in surgical patients within or outside of an OR [18].
Many such events involve performance of a wrong site nerve block [40-42]. A 2018 systematic review of wrong-site nerve blocks noted an incidence of 0.53 to 5.07 per 10,000 regional blocks [86].
Factors contributing to wrong patient, wrong procedure, wrong site, or wrong side surgery include poor communication regarding the surgical plan, failure to use site markings, incorrect patient positioning, surgeon fatigue, presence of multiple surgeons, multiple procedures on the same patient, unusual time pressures, emergency operations, and/or unusual patient anatomy [18].
Despite mandatory timeouts to identify patient, procedure, and laterality (table 1), wrong-site events continue to occur [87,88]. Even when an excellent timeout has been completed, one or more contributing factors may not have been eliminated. Examples include an imaging error or a medical record with charting errors [18].
●Approaches to risk reduction – Errors in identifying the correct surgical site can occur at any time in the perioperative period, including during imaging, charting, or preparation of preoperative consent forms [18]. Each step of the process requires a high level of attention beginning with review of the surgical consent and verification of the correct procedure and site, ideally with patient participation (see 'Reviews of informed consent' above and 'Timeouts' above). Use of a preoperative safety checklist that includes a surgeon-led briefing regarding the planned procedure, ideally with participation of all surgical team members, provides an additional opportunity to detect errors (table 2). (See 'Checklists' above and 'Briefings' above.)
For peripheral nerve blocks, the "stop-before-you-block," initiative is designed to prevent administration of regional anesthesia on the wrong side. The anesthesiologist pauses to check the correct side just before needle insertion, thereby interrupting performance of the block [86]. A regional survey of 173 anesthesiologists noted that full compliance with this initiative has not been achieved in the United Kingdom [89-91].
Infection risks
Infection risks for patients
Surgical site infection — Surgical site infections (SSI) are common complications of surgical and other interventional procedures, particularly if wounds are contaminated or dirty. We agree with recommendations for infection prevention noted in various professional guidelines. (See "Overview of the evaluation and management of surgical site infection".)
Implementation of surgical care bundles, or enhanced recovery protocols, is a strategy to reduce SSI risk [92]. Elements managed by anesthesia providers include [93,94] (see "Anesthetic management for enhanced recovery after major noncardiac surgery (ERAS)"):
●Standard precautions for anesthesia care team members – Standard precautions include hand hygiene, use of gloves, mask, eye protection, and gowns (when appropriate); high-level disinfection or sterilization of reusable laryngoscopes and video-laryngoscopes; and cleaning of computer keyboards and touchscreen computer monitors (or disinfection if there is obvious soiling or contamination) after each surgical case. (See "Overview of control measures for prevention of surgical site infection in adults".)
●Antibiotic prophylaxis – When an antibiotic is indicated preoperatively, most should be administered within 60 minutes of the skin incision or tourniquet inflation to achieve a bactericidal tissue concentration. For antibiotics that require infusion over more than 60 minutes, the infusion should be completed within 60 minutes prior to incision. In all cases, consideration should be given to the time required to achieve therapeutic tissue levels, not just completion of infusions. If a surgical case is greatly delayed such that more than 60 minutes elapse after completion of antibiotic administration, an additional dose may be indicated to preserve tissue concentration. For example, if cephalosporin 2 grams was administered as an initial dose >60 minutes prior to incision, an additional dose of 500 mg would be indicated. Antibiotics should be re-dosed at appropriate intervals (table 4). (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults".)
●Safe practices for administration of intravenous (IV) medications – Use safe vial access and injection practices. Note that sterile injectable medications are used as soon as possible after preparation, with prompt disposal of medication syringes and vials at the end of each case or after their expiration date [94-96]. (See "Prevention of perioperative medication errors", section on 'Avoid multiuse vials'.)
In addition, IV fluids are used as soon as possible after spiking the solution bag. However, no bacterial growth was noted in any samples drawn at the time of preparation and at 24 hours after spiking 1000 mL bags of normal saline (n = 127) or 5% dextrose in water (n = 129) [97].
Bacterial transmission from the anesthesia work station and anesthesia providers' hands is a root cause of postoperative infections in as many as 16 percent of patients undergoing surgery, including gram-negative, hospital-acquired infection [94,98,99]. One study used fluorescent indicator dye to demonstrate that patient oral contents spread from the hands of the anesthesia provider to most nearby work surface areas in the OR within an hour of endotracheal intubation [100]. Double gloving with removal of the top set of gloves immediately after passing the endotracheal tube reduced the spread of the indicator dye.
●Maintenance of normothermia – Normothermia with temperature ≥35.5°C is achieved and maintained throughout a surgical case [92,101-103]. Warming devices are employed if necessary to maintain normothermia, including upper- and lower-body forced-air warming devices and blankets, insulation water mattresses, and devices for warming all IV fluids [103-106]. In some cases, it may be necessary to adjust the OR temperature to maintain body temperature. However, hyperthermia is avoided. (See "Overview of control measures for prevention of surgical site infection in adults", section on 'Maintain normothermia' and "Perioperative temperature management".)
●Avoidance of hyperglycemia – Blood glucose level is maintained <180 mg/dL (<10 mmol/L), but hypoglycemia (ie, serum glucose concentration <40 mg/dL [2.2 mmol/L]) is carefully avoided [107]. (See "Perioperative management of blood glucose in adults with diabetes mellitus" and "Overview of control measures for prevention of surgical site infection in adults", section on 'Glucose control'.)
●Considerations regarding supplemental oxygen – We do not routinely administer a high fraction of inspired oxygen content (FiO2). The Centers for Disease Control and Prevention 2017 Guidelines for Prevention of Surgical Site Infection state that the optimal target level, duration, and delivery method of O2 is an unresolved issue, and that further studies are needed to evaluate the effect of high FiO2 on SSI and other outcomes [108,109]. (See "Mechanical ventilation during anesthesia in adults", section on 'Oxygen supplementation and surgical site infection'.)
Although a high FiO2 may be appropriate for some surgical patients, data are conflicting regarding the benefits of supplementing oxygen (O2) beyond the level required to achieve normoxemia. In one 2019 meta-analysis of 21 trials, use of a high perioperative FiO2 did not confer clear benefits, although SSI risk was reduced in patients who received a high FiO2 under general anesthesia with endotracheal intubation. Conversely, another 2019 meta-analysis of 20 trials concluded that liberal perioperative oxygen administration did not reduce SSI risk [110,111]. A third 2019 meta-analysis of 17 trials reported no definite signal of harm with administration of 80 percent FiO2 versus 30 to 35 percent FiO2. Furthermore, a 2018 meta-analysis of 25 randomized trials in 16,037 acutely ill adults who received liberal versus conservative oxygen therapy noted that administration of high FiO2 increased in-hospital mortality risk (relative risk [RR] 1.21, 95% CI 1.03-1.43) [112].
Central line infection — Catheter-related bloodstream infection (CRBSI) can occur after placement of a central venous catheter (CVC) in perioperative settings. (See "Central venous access: General principles".)
A checklist is used during CVC line insertion to ensure adherence to standard CRBSI guidelines, including hand washing, full barrier precautions for patient and anesthesiologist, chlorhexidine for skin disinfection, and avoidance of the groin if possible (table 7).
After placement of the CVC, contamination is minimized by swabbing the access port with appropriate antiseptic and accessing the port only following fastidious hand hygiene (ie, hand washing with antiseptic-containing soap or alcohol-based gels or foams). Although nonsterile gloves are typically worn, their use does not obviate the need for hand hygiene.
Contamination of the anesthesia machine — The anesthesia machine breathing circuit and its connection to the gas analyzer should be protected from becoming a vector of infection for subsequent patients via the anesthesia machine.
HME filters have been shown to effectively filter out the SARS-CoV-2 virus even with prolonged mechanical ventilation in the ICU [113]. The breathing circuit should contain two filters rated for viral filtration efficiency (VFE) (figure 1). Filters with the highest VFE are recommended.
●In adults, in whom the tidal volume is greater than 300 ml, one filter is placed at the airway. The gas sampling line should be connected on the side of the filter away from the patient (figure 1). A second filter is placed on the expiratory limb of the breathing circuit where it connects to the anesthesia machine. Thus, filtering is accomplished for the patient, the gas sampling line and the breathing circuit; the patient inhales gas that is filtered once, and exhales gas that is filtered once before entering the gas analyzer sampling system and twice before entering the anesthesia machine.
●In children less than 20 kg, one filter should be placed on the expiratory limb of the breathing circuit, but a standard size filter should not be added at the patient end of the breathing circuit because of added dead space [114]. For these patients, a filter with a smaller internal volume may be used, or the filter can be omitted. If the airway filter is omitted, a filter should be placed on the inspiratory limb and separate 0.2 micron filter should be added to the gas analyzer sampling line.
There are three types of breathing circuit filters: mechanical filters, electrostatic filters, and heat and moisture exchange filters (HMEFs) (picture 1) [115,116].
●Pleated mechanical filters contain a sheet of thick hydrophobic filter material that is pleated to increase the surface area and decrease resistance to flow. They have small channels and depth that traps particles, and typically have a VFE greater than 99.99 percent. Their VFE is not degraded by exposure to humidity and may also provide some heat and moisture exchange when placed at the airway. Most pleated filters have an internal volume of around 80 mL, and a minimum tidal volume requirement of 300 mL because of dead space ventilation.
●Electrostatic filters contain a thinner sheet of filter material that is less tightly woven, so that the resistance to flow is less for a given surface area. Electrostatic filters are so named because they have an electrostatic charge that helps to attract and trap particles. The VFE of an electrostatic filter is generally less than or equal to 99.99 percent, and this tends to decline as the filter becomes wet (eg, when exposed to high humidity) [117].
●HMEFs combine a heat and humidity exchanger and a filter (typically electrostatic-type) in one unit; thus, these are ideal for use in the breathing circuit after the Y-piece connector to provide both filtration and heat and humidity conservation.
Heat and humidity exchange (HME) devices without filters only provide heat and humidity exchange. These devices do not remove viral particles, and do not protect the anesthesia machine.
Membrane filters are different from the mechanical and electrostatic filters typically used in breathing circuits. In anesthesia, hydrophilic membrane filters are often used to filter liquids, such as epidural infusions. These are sieve filters, typically with a 0.2 or 0.22 micron pore size, which means that they will not allow any particle larger than the rated size to pass (as opposed to mechanical and electrostatic woven filters that allow a very small percentage of larger particles to pass). Hydrophobic membrane filters are in most gas analyzer water traps to prevent liquid and particles from entering the gas analyzer chamber. They may also trap viruses in the gas stream because all filters are more efficient at trapping particles in a gas medium than in a liquid medium. A 0.2 or 0.22 micron epidural filter can be added to the gas analyzer sampling line to provide additional filtration.
Surface contamination of anesthesiology equipment — Anesthesia equipment in the operating room can be contaminated with the patient's respiratory secretions and may therefore provide a mechanism for disease transmission. In United States health care settings, CDC states that routine cleaning and disinfection procedures are appropriate for SARS-CoV-2. Operating room equipment should be wiped down with cleaning solutions approved for viral pathogens. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Environmental disinfection'.)
Inadequate decontamination — The anesthesia machine and reusable equipment, meticulous routine cleaning should be performed according to manufacturer's recommendations [118].
After use in a COVID-19 positive patient, the gas sampling tubing should also be changed [119]. However, the water trap that receives the gas sampling line does not need to be replaced between COVID-19 positive patients if appropriately placed high-quality HMEF filters were used as directed (figure 1). Similarly, there is no evidence that the soda lime carbon dioxide (CO2) absorber needs to be changed between COVID-19 positive patient cases (over and above normal depletion) since it is protected by the filters in the breathing circuit and is highly alkaline and likely viricidal.
The need for terminal cleaning of internal components of the anesthesia machine and breathing system after exposure depends on the type of anesthesia machine and where the gas sample line was connected to the breathing circuit. In anesthesia machines where the gas analyzer exhaust is directed to the scavenging system, terminal cleaning is not necessary if appropriately selected and placed high-quality filters were used as directed. Terminal cleaning is also not necessary in machines where the sampled gas is returned to the circulating gas flow if the gas analyzer contains a water trap that filters particles the size of viruses or if the sample line was connected on the machine side of an airway filter. Some airway filters have an integrated gas sampling port on the machine side of the filter, which is always the preferred gas sample line connection site. In the event of overt or suspected contamination of the breathing system or internal components of the anesthesia machine (eg, failure to use filters, incorrectly placed filters, sampling of contaminated gas that is returned to the breathing system, or spillage of pulmonary edema fluid into the circuit), the specific manufacturer's recommendations for terminal cleaning will need to be followed. Some models of anesthesia machines require internal sterilization or a prolonged period of decontamination. Links to specific manufacturers’ recommendations can be found here.
Many hospitals have implemented enhanced environmental cleaning and disinfection protocols for rooms in which COVID-19 patients have received care, including the use of UV-C light [120] and/or hydrogen peroxide vapor. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Environmental disinfection'.)
For further information on cleaning of anesthesia equipment, refer to guidance from the APSF and ASA.
Infection risks for anesthesiologists — Anesthesiologists routinely care for patients known or suspected of harboring infectious pathogens that may be transmitted via contact, droplet, or airborne modes, as well as via needle stick injuries [94,121].
●Contact or droplet exposure – Hand hygiene and use of surgical masks in all cases, or properly fitted N95 facemasks when caring for selected patients, are essential practices to prevent transmission of infection, as discussed in a separate topic [122]. (See "Infection prevention: Precautions for preventing transmission of infection".)
●COVID-19 infection – Frequent hand hygiene and proper donning and doffing of personal protective equipment (PPE) are essential to prevent transmission of the novel coronavirus disease 2019 (COVID-19 or nCoV) disease or other respiratory infectious agents to health care workers (figure 2 and figure 3) (refer to the Centers for Disease Control and Prevention and the American Society of Anesthesiologists) [94,121,123,124]. (See "Infection prevention: Precautions for preventing transmission of infection".)
PPE includes gown, eye protection, glove (double glove technique), booties, and a fit-tested disposable N95 respirator mask (picture 2), ideally covered with a face shield or a regular surgical mask to avoid gross contamination with secretions, or a powered air-purifying respirator, also known as an isolation suit (picture 3). Further discussion regarding use of PPE, airway management, and safeguards for the anesthesia machine and other equipment during care of patients with suspected or confirmed COVID-19 is available in a separate topic. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control".)
Sharp object injury — Risks for needlestick or sharp object injuries to patients or OR personnel have been reduced due to advances in education, needle disposal, and engineering changes (eg, needleless devices, safety needles).
Management after potential exposure to a bloodborne pathogen (eg, human immunodeficiency virus [HIV-1], hepatitis B virus [HBV], hepatitis C virus [HCV]) is discussed separately. (See "Prevention of hepatitis B virus and hepatitis C virus infection among health care providers" and "Management of health care personnel exposed to HIV".)
Medication errors — Strategies to prevent medication errors such as administration of the wrong medication, wrong dose, or into the wrong site are reviewed separately. (See "Prevention of perioperative medication errors" and "Prevention of adverse drug events in hospitals".)
Retained surgical items — Prevention and management of accidental loss of surgical equipment (eg, sponges, instruments) within a wound are discussed in a separate topic. (See "Retained surgical sponge (gossypiboma) and other retained surgical items: Prevention and management".)
Equipment errors — Equipment can malfunction, or cause harm by not being available when needed (eg, bronchoscopes that go black when in standby mode). Most often errors due to equipment come from poor design [125]. In our experience, the most often reported incident involving equipment comes from mis-programing or malfunction of infusion devices.
●General considerations – Machines and equipment used by anesthesiologists and other OR personnel have been identified as potential causes of harm due to [125-128]:
•Misuse because of poor training or negligence
•Poor maintenance and upkeep
•Poor machine design
•Inherent risks in the use of each device
●Approaches to risk reduction
•Standardization of equipment and technology – Standardization reduces malfunction and human errors [129]. Examples include:
-Standards for monitoring including continuous noninvasive assessment of oxygenation. (See "Basic patient monitoring during anesthesia", section on 'Pulse oximetry'.)
-Fail-safe systems for anesthesia machines such as standardized unique pin-indexing systems for gas cylinders and gas lines to prevent delivery of hypoxic gas mixtures. Although not foolproof, such systems add reliability and safety [130]. (See "Anesthesia machines: Prevention, diagnosis, and management of malfunctions", section on 'Compressed gas supply malfunction' and "Anesthesia machines: Prevention, diagnosis, and management of malfunctions", section on 'Proportioning system or pressure sensor shut-off (fail-safe) valve malfunction'.)
-Standardization of the content and layout of difficult airway carts in all locations within an institution [131].
•Checkout of machines and equipment before use – An anesthesia machine checkout is performed prior to patient arrival in the OR, including presence and functioning of backup systems such as oxygen canisters and manual ventilation devices (Ambu bag, etc) (table 6) [132]. (See "Anesthesia machines: Prevention, diagnosis, and management of malfunctions", section on 'Standardized anesthesia machine checkout'.)
Checking function of advanced airway management equipment is also necessary before administration of any sedative, opioid, or anesthetic agent since these agents can cause respiratory depression. (See "Airway management for induction of general anesthesia", section on 'Preparation for induction of anesthesia'.)
Injury related to patient positioning
●General considerations – Positioning of an anesthetized patient can cause injuries. Examples include peripheral nerve damage (eg, compression or overstretching), pressure sores, deep vein thrombosis, compartment syndrome, and end-organ damage due to position-related hypoxemia and hypotension.
Details regarding prevention of specific injuries in the supine, Trendelenburg, reverse Trendelenburg, lithotomy, sitting (beach chair), lateral decubitus, and prone positions are discussed separately. (See "Patient positioning for surgery and anesthesia in adults".)
●Considerations for specific procedures – Injuries related to positioning for specific procedures are discussed in individual topics:
•Sternal retraction – Use of a sternal retractor after sternotomy, particularly during cardiac surgery with internal mammary dissection, has been associated with brachial plexus injury, upper arm compression by the retractor resulting in radial nerve injury, and exacerbation of cervical spine arthritis symptoms if the patient's head is not completely supported on the head cushion. (See "Anesthesia for coronary artery bypass grafting surgery", section on 'Positioning'.)
•Venous air embolism – Whenever the surgical field is above the level of the right atrium, air may be entrained into the venous system with resultant venous air embolism. Separate topics discuss prevention, detection, and treatment of air embolism in the beach chair sitting position or during sitting craniotomy (table 8). (See "Patient positioning for surgery and anesthesia in adults", section on 'Sitting' and "Anesthesia for craniotomy", section on 'Sitting position'.)
Venous air embolism may also occur during laparoscopy or endoscopic retrograde cholangiopancreatography [133]. (See "Uncommon complications of endoscopic retrograde cholangiopancreatography (ERCP)", section on 'Portal vein gas and air embolism' and "Air embolism", section on 'Surgery and trauma'.)
Eye injury or vision loss — Corneal abrasions in the perioperative period are common but typically preventable. Postoperative vision loss is a rare injury that has been reported after procedures in the prone position (eg, spine surgery). Eye injuries are discussed separately. (See "Postoperative visual loss after anesthesia for nonocular surgery".)
Retained surgical items — A surgical item such as a surgical sponge, instrument, tool, or device may be unintentionally left inside the patient at the completion of a surgical procedure. Prevention and management of this problem are discussed separately. (See "Retained surgical sponge (gossypiboma) and other retained surgical items: Prevention and management".)
Radiation injury — Risks of exposure of patients and OR personnel to ionizing radiation and approaches to risk reduction are discussed separately. (See "Radiation-related risks of imaging" and "Anesthesia for magnetic resonance imaging and computed tomography procedures", section on 'Radiation risks'.)
Electrical injury — Electrical injury can cause respiratory paralysis, seizures, muscle contractions, or ventricular fibrillation [134]. Electricity also dissipates energy and increases temperature in body tissues, which may cause burns or cellular death. Patients and staff are at risk of electrical shock or electrocution if they come into contact with a defective device (or a "hot," wire); electricity can flow through their body into the ground. For staff, flow would be into the floor. For patients, flow would be into the OR table or another grounded surface.
●General precautions to prevent electrical injury in the OR – Regulations for OR environments mandate institutional risk management for potential electrical injuries by using one of two methods in each OR (see "Electrical injuries and lightning strikes: Evaluation and management"):
•Making the entire OR an isolated power source, whereby any leak of electrical current is recognized by the line isolation monitor and an alarm sounds.
•Ensuring that each electrical device in the OR is equipped with a ground fault circuit interrupter, whereby any leak of electrical current trips the power outlet connecting the faulty device to electricity.
●Precautions during use of electrocautery
•Electrocautery devices may cause thermal burns, hemorrhage, device failure, or fire. Strategies to prevent these complications are discussed separately. (See "Overview of electrosurgery".)
•Patients with a pacemaker or implantable cardioverter-defibrillator require special precautions because of the electromagnetic interference caused by electrocautery, particularly if a monopolar device is employed. Management of these implantable electronic devices in the perioperative setting is described in a separate topic (algorithm 1 and algorithm 2). (See "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator".)
•Patients with neuromodulation devices such as deep brain stimulators, vagal nerve stimulators, spinal cord stimulators, etc, continue to increase in numbers; nearly all should be turned off prior to surgery, and electrocautery can reprogram the devices, or cause the tip of the electrode to heat up [135].
Operating room fires — Most OR fires are preventable with communication and appropriate education, including assessment of risk during the briefing or timeout. Causes and prevention of fires in the OR are reviewed separately (algorithm 3 and algorithm 4). (See "Fire safety in the operating room".)
Accidental awareness during anesthesia — Recognition, prevention, and management of a possible intraoperative awareness event (ie, intraoperative consciousness with postoperative recall of intraoperative events) are discussed in a separate topic. (See "Accidental awareness during general anesthesia".)
INSTITUTIONAL APPROACHES TO SAFETY IMPROVEMENT — Institutional interventions that improve safety in the OR include maintaining hospital accreditation; implementing incident reporting, team training, and simulation training; applying appropriate evidence-based best practices; and establishing a culture of safety.
Hospital accreditation — The Joint Commission has set national patient safety goals; hospital accreditation depends on demonstration of implementation of elements of performance measures and improvements [136].
Implementation of evidence-based best practices — Clinical practice guidelines are defined by the Institute of Medicine (IOM) as "statements that include recommendations intended to optimize patient care, that are informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options" [137]. Examples in the OR include antibiotic administration, glycemic control, and maintenance of normothermia [92]. Another example is establishment of guidelines for overlapping surgery (defined as more than one procedure performed by the same primary surgeon with scheduling such that the start time of one procedure overlaps with the end time of another) [138].
Widespread implementation of evidence-supported guidelines typically requires several years [139]. The IOM has recommended that wording in guidelines supported by strong evidence should include measurements that can be recorded by the institution so that adherence to standards can be tracked [140]. (See "Overview of clinical practice guidelines", section on 'Effects of guidelines on practice' and "Overview of clinical practice guidelines", section on 'Implementing practice guidelines'.)
Team training — Team training programs for OR personnel (eg, surgeons, anesthesiologists, nurses, scrub technicians) teach effective communication strategies, how to conduct effective timeouts and briefings, how to challenge other team members when a safety issue is identified, conflict management, and implementation of safe care transitions. Such training decreases communication failures, reduces technical errors, and improves team member satisfaction [32-38,141]. Similar team training efforts have been successfully implemented in obstetrical units. (See "Reducing adverse obstetric outcomes through safety sciences", section on 'Teamwork training'.)
In one large study in the Veteran's Administration Hospital system, surgical mortality was reduced after formal medical team training based on the aviation-style non-technical skills training that included crew resource management (CRM) tenets [52,142]. This training included communication techniques, situational awareness, leadership, and conflict resolution [36,37]. Another teamwork training program is Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS), created and implemented by the Agency for Healthcare Research and Quality (AHRQ), and not strictly based on CRM tenants [32,38]. Positive effects of TeamSTEPPS training include reduced overall surgical morbidity and mortality. However, evidence indicates that training must be repeated on a regular basis to maintain benefit [32].
Simulation training — Simulation training that teaches crews to work together in simulated crisis situations is also critically important in aviation safety. In surgical and anesthetic settings, simulation has been used to:
●Teach nontechnical skills (eg, teamwork and communication) [29-31,143].
●Test interventions to reduce error [144].
●Develop and practice crisis protocols [33,145-151], with standardized simulation-based assessment that can identify performance gaps and opportunities for improvement [152]. (See "Reducing adverse obstetric outcomes through safety sciences", section on 'Simulation and drills'.)
●Understand effects of stress and fatigue [153-156]. In a 2019 meta-analysis of nearly 120,000 surgical procedures performed during daytime hours versus more than 46,000 procedures performed during after-hours shifts, mortality was lower for cases performed during the daytime (odds ratio [OR] 0.67, 95% CI 0.51-0.89), as was morbidity (OR 0.71, 95% CI 0.53-0.94) [157].
●Develop technical skills such as airway management, ultrasound-guided regional block, and central line placement. [143].
Simulation training is often conducted at a high-fidelity simulation center using programed manikins and elaborate scenarios [33,158]. However, effective interdisciplinary simulation training in the actual clinical environment can be done without any specific tools. Teams simply walk and talk through a simulated crisis by identifying roles, specifying steps to be taken, and building teamwork [159,160].
Incident reporting — Incident registries have been used to identify and reduce risks in settings and situations that have resulted in errors committed by an individual or team [161]. Although there has been a proliferation of incident reporting registries, there is no clear evidence that these significantly change health care [161]. However, reported information can be used to effect improvements. For example, reviews of the Closed Claims Database in anesthesiology have led to significant changes in anesthetic and surgical practice resulting in risk reduction for cardiac arrest after spinal anesthesia, OR fires, and positioning injuries (eg, nerve injuries, brain injury associated with beach chair positioning, postoperative vision loss associated with prone spine surgery) [162].
Other incident registries are focused on contemporaneous reporting with immediate review of near-misses and adverse events to rapidly identify system vulnerabilities. For example, the American Society of Anesthesiologists (ASA) established the Anesthesia Incident Reporting System (AIRS) in 2011 for reports of near misses or actual events by any anesthesia provider who may choose to file the report with either anonymity or confidentiality [163]. Other examples are the Canadian Anesthesia Incident Reporting System (CAIRS) and the Australia and New Zealand Tripartite Date Committee (ANZTADC) system [164,165]. Institutional implementation of mandatory reporting of adverse events detected with anesthesia information management systems may decrease the incidence of preventable events [166].
Another database of mandatory medical device reports submitted to the FDA is managed by the Manufacturer and User Facility Device Experience (MAUDE). Such registries are modeled on the Aviation Safety Reporting System [167].
Monitoring for any intraoperative deviation from optimal clinical care (ie, nonroutine events) has been suggested for perioperative safety research. In one study of video recordings from 511 cases, one or more nonroutine events occurred in 22 percent [168]. The most common contributory factors involved human factors and included medication errors or equipment issues (37 percent), and patient-related factors involving cardiovascular comorbidity (37 percent) or the airway (33 percent).
Establishing safety culture — A just safety culture holds each individual accountable for their actions [169,170].
Unit-based safety culture programs have been designed for the OR and other hospital settings to accomplish the following goals:
●Provide education to improve awareness about patient safety and quality of care.
●Empower staff to take charge, voice concerns, and improve safety in their unit.
●Create partnerships between units and hospital managers to improve organizational culture and provide resources for unit improvement efforts.
●Provide tools to investigate and learn from defects, foster excellence, and promote resilience [171,172].
A pre- and post-implementation evaluation of a Comprehensive Unit-Based Safety Program (CUSP) in two surgical intensive care (ICU) units noted improvement in safety culture and reduction in ICU length of stay, medication errors, and possibly nursing turnover [173-175]. Elements of CUSP include:
●Educating staff regarding safety science.
●Identification of potential hazards to inform subsequent care [169].
●Learning from previous problems [51]. Rather than employing a work-around or a "band aid," solution, clinicians design system interventions that reduce harm to future patients [48]. The following questions are asked and answered regarding each near-miss or actual adverse event:
•What happened?
•Why did it happen?
•What can we do to reduce this risk?
•How do we prove that we reduced this risk?
●Implementing tools to improve teamwork, communication, and the safety culture [51]. Tools include briefings, debriefings, and incident reporting. (See 'Briefings' above and 'Debriefings' above and 'Incident reporting' above.)
●Partnering with a hospital executive to support local efforts, provide needed resources, hold the team accountable, and inform senior leadership of safety hazards to patients.
●Ongoing measurement, feedback, and improvement. CUSP teams meet regularly to review safety issues, investigate newly identified defects, and design safer systems of care. An example is continual evaluation of failure to rescue events (defined as death of a patient after one or more potentially treatable complications), which have been identified as an important surgical quality indicator [176].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Patient safety in the operating room".)
SUMMARY AND RECOMMENDATIONS
●Human errors – Individual human errors in the operating room (OR) include (see 'Human error: Types and prevention' above):
•Action-based (ie, skill) errors – Prevention includes implementing known safety precautions, standardizing techniques, and building redundancy into systems (eg, two-person checks).
•Decision-based (ie, judgment or knowledge) errors – Prevention includes use of cognitive aids, simulation training to practice decision-making during crises, and implementation of evidence-based best practices.
•Technical errors – Prevention includes standardizing techniques, using technology such as ultrasound, or consulting with another provider with additional proficiency or expertise.
•Communication-based failures – Prevention includes preoperative briefings, use of structured communication, and teamwork training to improve communication skills.
●Approaches to risk reduction – General approaches to risk reduction in the OR include (see 'General approaches to risk reduction' above):
•Review of informed consent – Review the informed consent in the preoperative area and again before surgical incision (or regional block placement), including checks of patient identity (using dual identifiers), procedure to be performed, and the site, side, or level of the procedure (table 1). (See 'Reviews of informed consent' above and 'Timeouts' above.)
•Checklists and briefings – Examples include:
-The anesthesia machine checkout is performed by the anesthesia provider (table 6).
-We suggest use of a preoperative checklist, such as the World Health Organization (WHO]) checklist (table 2) (Grade 2C), ideally with a surgeon-led briefing and participation of the entire OR team (eg, surgeon, anesthesiologist, circulating nurse, scrub technician). This includes team introductions; checking patient identity and verifying the intended procedure and site; discussing antibiotic administration and deep venous thrombosis prophylaxis (table 4 and table 5); verifying blood product availability; determining appropriate monitoring strategies; verifying availability of surgical equipment, instruments, and implants; planning appropriate patient positioning; ensuring team understanding of procedural goals and critical steps; planning postoperative disposition; and inviting team members to voice concerns or questions.
-If a central venous catheter is inserted, a checklist is used to ensure adherence to standard guidelines that prevent catheter-related bloodstream infection (table 7) (See 'Checklists' above and 'Briefings' above.)
•Techniques to minimize distractions – Attempt to minimize distractions (eg, limiting extraneous personnel in the OR, surgical interruptions, noise level due to alarms, conversations, beepers, and music). (See 'Techniques to minimize distractions and disruptions' above.)
•Structure communication – Use structured communication, particularly during complex surgical cases or crisis situations. (See 'Structured communication' above.)
•Debriefings and handoffs – Use a debriefing to identify hazards and suggest improvements after the procedure, and a formal handoff process during transition of care. (See 'Debriefings' above and "Handoffs of surgical patients".)
●Risk reduction strategies – Preventable hazards for patients in the OR may result in an adverse event. These include performance of the wrong surgical procedure or on the wrong site, infection of the bloodstream or surgical site, sharp object or needlestick injury, administration of the wrong medication or dose, equipment malfunction, positioning injuries, eye injury, retention of surgical items within the wound, and accidental awareness during general anesthesia. Other preventable physical hazards for both patient and OR personnel include fires and electrical or radiation injury (algorithm 3 and algorithm 4). (See 'Risk reduction strategies for specific hazards' above.)
●Institutional approaches – Institutional approaches to improve patient safety include implementing evidence-based best practices, team training, simulation training, incident reporting, and establishing a safety culture. (See 'Institutional approaches to safety improvement' above.)
