INTRODUCTION — Transtracheal oxygen (TTO) therapy refers to the delivery of long-term oxygen therapy (LTOT) through a transtracheal catheter (picture 1). It is an alternative to conventional LTOT, which is delivered through a nasal cannula.
The benefits of TTO therapy, patient selection, complications, and reimbursement are discussed in this topic review. Other issues related to LTOT are discussed separately. (See "Long-term supplemental oxygen therapy" and "Evaluation of patients for supplemental oxygen during air travel" and "Portable oxygen delivery and oxygen conserving devices" and "The evaluation, diagnosis, and treatment of the adult patient with acute hypercapnic respiratory failure".)
Transtracheal oxygen procedure kits are no longer available — In June 2021, the company that made the TTO procedure kit and catheters ceased all operations. Patients using TTO are encouraged to contact their durable medical equipment (DME) company to see if they can obtain catheters from another supplier. When TTO replacement catheters are no longer available or functional, patients will need to remove the TTO catheter and resume use of nasal cannula oxygen. Health care providers will need to assess oxygen requirements during this transition. Oxygen flow rate requirements are likely to increase significantly with the transition to nasal cannula, and dyspnea may worsen as well.
If the catheter is removed permanently, the stoma will spontaneously close in several days to a week as it heals and requires no additional topical treatment or closure.
BENEFITS — Transtracheal oxygen (TTO) therapy offers several potential benefits [1]. Most studies that have examined the efficacy of TTO have used the subject as his or her own control. In these short-term physiologic studies, patients with an existing transtracheocutaneous fistula usually received interventions related to tracheal gas delivery in a random order, and then were compared to controls with no tracheal flow [2,3]. In the long-term clinical studies, data collected after initiation of TTO therapy were compared to data collected while the patient was receiving LTOT by nasal cannula [4-8]. One trial randomized 43 patients to receive TTO or long-term oxygen therapy (LTOT) via nasal cannula for the duration of the trial [9].
TTO was found to have the following effects when compared to LTOT delivered via nasal cannula (table 1):
●Reduces the oxygen flow that is required to achieve the same arterial oxyhemoglobin saturation, both at rest (55 percent reduction) and during exercise (30 percent reduction) [4]
●Improved exercise capacity was observed in two studies; however a third study found no increase in exercise capacity with TTO compared to nasal cannula, when controlled for oxygen saturation [3,5,9]
●Improves the room air alveolar to arterial oxygen tension gradient (ie, A-a gradient) [6,9]
●Reduces erythrocytosis and improves cor pulmonale [4,7,9]
●Reduces or maintains arterial carbon dioxide tension (PaCO2) [2]
●Corrects hypoxemia that was refractory to LTOT delivered by nasal cannula [7]
●Improves activity and mobility [9]
●Improves physical, social, and psychological function [9]
●Improves compliance (daily duration of oxygen use) [8]
●Reduces days of hospitalization [5]
Transtracheal flow (of air or oxygen) also has physiologic advantages compared to breathing without transtracheal flow (table 2). Specifically, transtracheal gas delivery reduces inspired minute volume, dead space volume, and tidal volume [2,10-12]. It also shortens the time of inspiration and decreases the work of breathing [10]. Higher tracheal flows produce greater benefit than lower flows [1].
Anecdotal benefits have also been attributed to TTO therapy. These include reduced dyspnea, greater comfort, elimination of nasal cannula complications, improved self image, and possibly decreased readmission rates for COPD exacerbation [13].
TTO therapy increases the number of hours per day that supplemental oxygen is used [8,13]. Increased compliance with oxygen therapy has been shown to improve survival; however, the effect of TTO on survival has not been studied [14].
PATIENT SELECTION — Transtracheal oxygen (TTO) therapy is most appropriate for patients with chronic hypoxemia who require a low oxygen flow rate and are in an early stage of their illness, because such individuals are most likely to experience improved quality of life for many years. Benefit is less likely and complications are more common when TTO therapy is initiated in patients who require high flow rates during a preterminal phase of their illness (table 3) [13,15]. However, even patients with advanced disease may still derive considerable benefit [7,16,17]. (See 'Benefits' above.)
Indications for the need for supplemental oxygen in general are discussed separately. (See "Long-term supplemental oxygen therapy".)
Indications — Indications for TTO therapy include (table 1):
●Patient preference
●The need for any of the benefits described above, such as reduced dyspnea, improved exercise capacity, or improved mobility (see 'Benefits' above)
●Complications of long-term oxygen therapy (LTOT) delivered by nasal cannula, especially if the complications impact compliance, such as frequent epistaxis
●Despite LTOT via nasal cannula, the patient has cor pulmonale, erythrocytosis, or nocturnal hypoxemia
In patients who required LTOT prior to an episode of respiratory failure requiring tracheostomy for mechanical ventilation, consideration may be given to decannulation to TTO when they wean from mechanical ventilation; this will avoid the risks of a procedure to create a tracheocutaneous fistula.
TTO therapy can be initiated as an intervention of last resort in patients who have hypoxemia that is refractory to LTOT via nasal cannula [18]. However, the risks versus the benefits of TTO therapy in this situation should be carefully weighed and discussed with the patient because such patients are more likely to experience a complication.
In the authors’ experience with over 500 patients, initial high flow rates (greater than or equal to 7 L/min via TTO) may increase the risk for tracheal irritation, bronchorrhea, and minor bleeding from mucosal irritation, although many patients adapt well to high flow rates, and many of the benefits of TTO still occur in this patient population. Approximately 50 percent of our patients have severe interstitial lung disease (ILD). As hypoxemia worsens with disease progression, many patients with ILD still benefit from TTO, and many have uptitrated their flow rates to 9 L at rest, and 12 to 15 L with exercise, over time. However, these high flow rates are not recommended as initial settings unless absolutely necessary to treat refractory hypoxemia. Additionally, patients receiving heated high flow oxygen (greater than or equal to 30 L/min), more commonly in the hospital or acute long-term care settings, have generally not done well with TTO as a "rescue" therapy for refractory hypoxia in these settings.
Despite broad support from patients with TTO, the frequency of TTO remains low in the total population of patients requiring LTOT. There are several reasons for this low frequency, and among them are [19-21]:
●Lack of familiarity with TTO within the pulmonary community
●Perceptions, or misperceptions, about the complexity and risks of the procedure
●Financial barriers to reimbursement for catheter replacement cost, which is bundled into the payment to suppliers for durable medical equipment (DME) under the Centers for Medicare and Medicaid Services (CMS) capped rental and competitive bidding program
●Limited studies in a small patient population where data are insufficient to meet evidence-based requirements
●Limited access to professionals trained in the procedure and follow-up care.
Contraindications — TTO therapy should not be offered to patients who are in acute respiratory distress, medically unstable, or have unsuitable anatomy, such as a severe upper airway obstruction, prior severe airway trauma or extensive neck surgery, or pleura herniated into the site selected for creation of the tracheocutaneous fistula. It also should not be initiated in patients who cannot consistently perform their own catheter care, are nonadherent with medical care, or have a severe anxiety disorder (table 4).
Some patient characteristics do not preclude TTO therapy, but may predispose an individual to complications and should be carefully considered when determining whether a patient is appropriate for TTO therapy. They include poor pulmonary reserve, obese neck or other anatomical challenges, moderate to severe anxiety, bronchial hyperreactivity, copious or unusually viscous sputum, bleeding disorder, or poor healing. Management of medications that increase bleeding risk would be that same as for any other interventional procedure or surgery.
GENERAL APPROACH — Transtracheal oxygen (TTO) therapy is usually coordinated by a team that consists of a physician, a surgeon, and a respiratory care practitioner (respiratory therapist) or nurse [13]. Close communication among the clinicians, nurses, and respiratory care practitioners comprising the TTO team is central to the success of a TTO program. Hence, transtracheal oxygen should be viewed as a “program of care,” and not just a medical device.
Centers with more experience report fewer technical problems, which suggests that there is a learning curve [8,22]. Thus, it is advisable that institutions introduce TTO in a graduated fashion, starting with ideal candidates and progressing to more difficult patients once there is more substantial institutional experience [13].
Once it has been determined that TTO therapy is appropriate, it is usually initiated using the Spofford Christopher Oxygen Optimizing Program (SCOOP), which consists of four distinct phases [1,13,15,23-25].
Phase I — Phase I involves preparation for creation of a tracheocutaneous fistula, in which the transtracheal catheter will reside (table 5). This consists of a preprocedure evaluation and patient education.
Preprocedure evaluation — All patients should undergo a preprocedure evaluation that is aimed at optimizing baseline pulmonary status and identifying and excluding poor candidates for tracheocutaneous fistula creation (table 3) (table 4). The procedure should be delayed if the patient is unstable or his or her condition could be better optimized [13]. The evaluation includes:
●A directed history and physical examination should be performed to identify any new or increased symptoms (eg, increased sputum) or signs (eg, wheezing) that indicate that the patient's medical condition is not optimized. Neck anatomy is assessed to make sure tracheal interspaces are easily identifiable (figure 1).
●A chest radiograph is necessary to exclude patients with anatomic contraindications or challenges to the procedure, such as pleura herniated into the site selected for creation of the tracheocutaneous fistula or a deviated trachea.
●Spirometry with measurement of the forced expiratory volume in one second (FEV1) pre- and post-bronchodilator should be performed to evaluate ventilatory reserve and assess risk for bronchospasm. Patients prone to bronchospasm should be monitored more closely through all steps, especially during initial catheter changes.
●Arterial blood gases should be reviewed to determine the severity of the hypoxemia (ie, the arterial oxygen tension, PaO2) and the ventilatory impairment (ie, the pH and arterial carbon dioxide tension, PaCO2). These values are useful in confirming the need for supplemental oxygen therapy, assessing clinical stability, and determining the likelihood that a patient will benefit from TTO. The severity of ventilatory impairment (reduced FEV1 or hypercarbia) that precludes TTO is determined on a case-by-case basis after carefully weighing the importance of the potential benefits, the experience of the care team, and the risks of the procedure (table 4).
Patient education — Comprehensive teaching is important because patients must be able to reliably care for the catheter and recognize potential complications. Ideally, patients should view a training video, receive an educational booklet, participate in a question and answer session with a staff member, and speak to a patient who is using transtracheal oxygen, if available [13,15,23,24]. It is also important that the patient understand that the procedure is not a treatment for their underlying disease, but an oxygen delivery system to aid oxygen delivery, reduce dyspnea, and improve exercise tolerance.
Phase II — Phase II involves creation of the tracheocutaneous fistula (table 6). Two techniques are available, the modified Seldinger technique (MST) and the Lipkin procedure. We prefer the Lipkin procedure for the reasons described below.
Modified Seldinger technique — The modified Seldinger technique (MST) refers to the use of an introducer needle, followed by a guidewire over which a catheter is passed. A detailed discussion is available [13]. The following is an overview of the technique for creating a transcutaneous fistula:
●Carefully identify the first or second tracheal interspace (figure 1)
●Administer a local anesthetic (eg, lidocaine 1 or 2 percent, about 3 to 5 mL)
●Prepare the site with chlorhexidine and drape the area with sterile towels
●Reidentify the correct tracheal interspace and insert the introducer needle percutaneously with the bevel facing away from the head
●Thread the matching guidewire through the introducer needle and into the lumen of the trachea and then remove the introducer needle
●Create the tracheocutaneous fistula by advancing a single dilator over the guidewire with a gentle twisting motion
●Insert the nonfunctioning stent, remove the guidewire, and suture the stent in place [13]
●Prescribe a prophylactic oral antibiotic (effective against streptococcus and staphylococcus), which is typically given for 7 days total therapy
The nonfunctioning stent remains in position for one week. A guidewire is then threaded through the stent; the stent is removed over the guidewire. A transtracheal catheter is then inserted over the guidewire, which is subsequently removed. Catheters come in three different lengths (9, 11, and 13 cm) to allow proper placement of the catheter approximately 2 to 3 cm superior to the main carina. The 11 cm catheter length is most commonly used and proper placement is confirmed on a post-placement chest radiograph. TTO therapy can then be initiated [13]. The one week delay reduces the risk of subcutaneous emphysema.
Lipkin procedure — The Lipkin procedure (ie, mini-tracheotomy) is a surgical approach to tracheocutaneous fistula creation that avoids some of the shortcomings of the MST [1,26]. It is generally done under moderate sedation (conscious sedation), but can be performed under general anesthesia administered via a laryngeal mask airway (LMA) in the operating room. The procedure requires less than one hour and the patient remains in the hospital under observation until the next day. A general outline of the procedure is as follows:
●Ascertain adequate conscious sedation.
●Carefully identify the first or second tracheal interspace (figure 1).
●Prepare the site with chlorhexidine and drape the area with sterile towels.
●Reidentify the correct tracheal interspace (usually the first or second tracheal interspace) and make a vertical incision at the selected site. Flaps of full-thickness skin are elevated, and cervical fat is removed down to the strap muscles.
●Separate the strap muscles at the midline, exposing the anterior wall of the trachea.
●Suture the skin flaps to the undersides of the exposed sternothyroid muscles, thereby forming an epithelialized tract that extends to the anterior wall of the trachea.
●Make a small horizontal incision between the tracheal cartilage rings, and puncture the trachea at this incision using a device called a tracheal punch. The tracheal punch resects a small window of cartilage.
●Insert the 3 mm tracheostomy tube that comes with the surgical kit into the tract using a stylette. Post-procedure, humidified air is administered via a trach collar placed over the tracheostomy tube. Oxygen continues to be applied via nasal cannula or mask.
●Prescribe a prophylactic oral antibiotic (effective against streptococcus and staphylococcus), which is typically given for five days total therapy.
During the postoperative period, we typically use judicious amounts of narcotic analgesics, for analgesia and cough suppression. If a narcotic is not needed for analgesia, cough can usually be managed with a nonnarcotic cough suppressant or by injecting 1 to 5 mL of 1 percent lidocaine (without epinephrine) into the catheter every four to six hours.
The following day, a guidewire is threaded through the stent, the stent is removed, the transtracheal catheter is inserted, and the guidewire is removed leaving only the catheter in position. The catheter is held in position by a bead chain necklace. Placement of clear medical tape over the necklace, just lateral to the catheter on each side, further secures the catheter in position. The oxygen tubing is also secured by a clip to the patient's clothing to minimize dislodgement of the catheter. At this time, the patient can begin to receive TTO.
Comparison — Tracheocutaneous fistula creation using the MST has several shortcomings. The catheter cannot be removed by the patient and thoroughly cleaned until the tract is mature and the patient has been trained to periodically remove and reinsert it. This usually takes less than four weeks. During this time, there is a tendency for mucus to adhere to the tip of the catheter and accumulate (ie, form a mucus ball), which can cause upper airway obstruction and respiratory deterioration. The care team must periodically remove the catheter over a guidewire to clean it. In addition, the tracheocutaneous fistula can close (ie, lost tract) if the catheter is dislodged. Chondritis and chronic tract inflammation can develop in tracheal cartilage inadvertently exposed or injured during the procedure, which may also stimulate keloid formation in predisposed individuals. All of these adverse sequelae can compromise the tracheocutaneous fistula, making catheter insertion difficult.
Observational studies suggest that the Lipkin procedure is well tolerated and has a number of benefits compared to the MST [19,26]. In a review of 33 Lipkin procedures compared with 64 historical controls who underwent MST, the following observations were made [26]:
●The tracheocutaneous fistula created by the Lipkin procedure matured faster than that created by the MST (two versus eight weeks).
●Mucus ball formation is lower with the Lipkin procedure (5 to 10 percent) compared with the MST (10 to 15 percent). The rate of tract loss is also lower with the Lipkin procedure.
●Resection of a window of cartilage reduced the incidence of chondritis (12 versus 25 percent) and keloid formation, which may further reduce the risk of lost tracts.
●The surgically created tract had fewer instances of subcutaneous emphysema.
●With the Lipkin procedure TTO therapy was initiated one day after the procedure, rather than one week.
Phase III — Phase III involves the initiation of TTO through an immature tracheocutaneous fistula (ie, tract) (table 7). The main goals of this phase are to prevent symptomatic mucus balls, prevent tract loss, and monitor tract healing. This phase applies equally to tracts created by either the modified Seldinger technique or the Lipkin procedure.
Once the nonfunctioning stent or mini-tracheostomy has been replaced with a transtracheal catheter and secured with a fitted bead chain necklace, TTO therapy can begin. Oxygen flow is titrated to achieve an adequate oxyhemoglobin saturation during rest and exertion, as measured by pulse oximetry. Patients, family members, and caregivers are instructed about catheter care, which includes cleaning the internal lumen of the catheter with instilled saline and a cleaning rod at least twice daily. Patients should return two to four times to the respiratory therapist over the next two weeks to reinforce education, evaluate tract maturity, and strip mucus from the outside of the catheter by exchanging the catheter over the guidewire, a procedure performed by the respiratory therapist on the TTO team.
Normal sequelae encountered during the first few days include mild tenderness at the insertion site, scant hemoptysis, or a transient increase in cough and sputum production. Patients may have an air leak through the stoma for a few days, which can affect speech. Gentle pressure on the stoma makes phonation easier if this occurs.
Additional humidification to the oxygen delivery system is necessary to minimize airway dryness and irritation.
The convention has been to administer TTO with a continuous flow of oxygen. Pulse or demand oxygen delivery systems (DODS) that require one lumen for delivery and a separate lumen for sensing inspiratory effort are not compatible with the single lumen TTO catheter. As a result, specific DODS designs utilizing alternating sensing and delivery through a single lumen have been assessed in terms of adequacy of oxyhemoglobin saturation and oxygen savings [27,28]. However, it does not appear that DODS adds substantially to oxygen conservation achieved with TTO alone. (See "Portable oxygen delivery and oxygen conserving devices".)
Tract loss — Dislodgement of the transtracheal catheter can result in tract loss. To minimize the likelihood of tract loss, patients should be instructed about what to do if inadvertent dislodgement of the transtracheal catheter occurs:
●Return to nasal cannula oxygen
●Clean the catheter and lubricate it with sterile, water soluble jelly
●Gently attempt reinsertion
●Assistance should be sought from the TTO team if reinsertion is not successful after two attempts
●If the team is also unsuccessful, it may be possible to insert a guide wire and then the catheter
Multiple reinsertion attempts are not advised, because this can create a false tract, with misplacement of the catheter pre- or paratracheally into the anterior mediastinum. Repeat tract creation can be considered if the tract cannot be recovered. The Lipkin procedure has a much lower rate of tract loss, compared to the MST [26].
Mucus accumulation — Mucus can accumulate around the distal tip of the catheter and form a mucus ball, which may be large enough to cause upper airway obstruction and respiratory deterioration. To prevent this, patients should be instructed about minimizing mucus accumulation and recognizing mucus accumulation.
●Measures to minimize mucus accumulation include adequate humidification of supplemental oxygen, frequent cleaning of the transtracheal catheter, adequate systemic hydration, and administration of a mucokinetic agent. We typically prescribe guaifenesin 600 to 1200 mg orally twice a day. In addition, for patients with COPD who are not on inhaled glucocorticoid therapy, we often add an inhaled glucocorticoid to decrease mucus production.
●Early recognition of mucus accumulation is facilitated by frequent monitoring by telephone, frequent follow-up visits, and patient education about symptoms that suggest mucus ball accumulation (eg, increased or severe cough, dyspnea, or wheezing).
Patients with a low FEV1 and weak cough may require more frequent catheter stripping because they are less likely to be able to expel accumulating mucus. Similarly, individuals requiring high TTO flows and those with copious or tenacious sputum are predisposed to mucus balls. Catheter stripping refers to removal of the catheter from the tract over a guidewire by the team, during which most of the mucus that has accumulated around the distal tip of the catheter will be scraped off by the removal process, and subsequently expelled by cough. Mucus that remains on the catheter can be manually removed during cleaning and then the catheter must be promptly reinserted over the guidewire.
Mucus ball accumulation is most common in Phase III, but can occur after years of uneventful TTO therapy. Approximately 10 to 15 percent of patients experience symptomatic mucus balls when the MST procedure is used, compared with 5 to 10 percent with the Lipkin procedure [7].
Phase IV — Phase IV involves the maintenance of TTO therapy through a mature tract, which is defined as a tract through which the catheter easily slips into position (table 8). The goal of this phase is for the patient to avoid complications through self care.
During Phase IV, a cleaning protocol should be customized to patient needs. Cleaning protocols can utilize cleaning the catheter while it is in position (as in Phase III) and cleaning the catheter once it has been removed. The removed catheter is replaced by a previously cleaned second catheter in an alternating fashion. The protocol can be adjusted according to symptoms. The majority of patients remove the catheter for cleaning twice per day to prevent mucus accumulation. Others do well with cleaning in place twice daily on most days, with removal for cleaning once or twice per week. Catheters should be replaced every three months to help with pulmonary hygiene and minimize colonization.
GENERAL COMPLICATIONS — Cough and mucus ball formation may occur, but generally decrease over time. Most complications are not life-threatening. Other complications are rare, but include subcutaneous emphysema, bronchospasm, hemoptysis, significant mucus collection, lost tracts, mucosal ulceration, chondritis, and infections [1,4,5,8,22,29-31]. One small case series described frequent lower respiratory tract infections that required hospitalization [32]. All of the patients in this report had severe interstitial lung disease, were immunosuppressed, and required a high oxygen flow rate.
Life-threatening complications have been described in case reports. These complications include airway obstruction from a massive mucus ball, extratracheal misplacement of the catheter, and pneumothorax with pneumomediastinum [33-40].
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: Supplemental oxygen".)
SUMMARY AND RECOMMENDATIONS
●Transtracheal oxygen (TTO) therapy refers to the delivery of long-term oxygen therapy (LTOT) through a transtracheal catheter (picture 1). (See 'Introduction' above.)
●TTO therapy offers several potential benefits, compared to LTOT delivered by nasal cannula, including reduced dyspnea, improved mobility, improved comfort, increased exercise capacity, and fewer days of hospitalization. (See 'Benefits' above.)
●Patients with chronic hypoxemia who require a low oxygen flow rate and are in an early stage of their illness are the most likely to experience improved quality of life when using TTO therapy, compared to LTOT via nasal cannula. (See 'Patient selection' above.)
●Reasons to choose TTO, instead of nasal cannula, include patient preference, reduced oxygen requirement, improved mobility, and avoidance of nasal cannula-related complications (table 1) (table 2). (See 'Indications' above.)
●We do not initiate TTO therapy in patients who are in acute respiratory distress, medically unstable, or have unsuitable anatomy. It also should not be initiated in patients who cannot consistently perform their own catheter care, are noncompliant with medical care, have severe upper airway obstruction, or have severe anxiety. (See 'Contraindications' above.)
●TTO therapy is usually initiated using the Spofford Christopher Oxygen Optimizing Program (SCOOP), which consists of four distinct phases (table 5 and table 6 and table 7 and table 8). However, the company that manufactured these kits has ceased production. It is not known if another source will become available. (See 'General approach' above and 'Transtracheal oxygen procedure kits are no longer available' above.)
●We suggest that the tracheocutaneous fistula be created using the Lipkin procedure, rather than the modified Seldinger technique (Grade 2C). (See 'Phase II' above.)
●Most complications of TTO therapy are minor, including subcutaneous emphysema, bronchospasm, hemoptysis, mucus collection, local chondritis, lost tracheocutaneous fistulas, and infections. Life-threatening complications are rare, but have been described. (See 'General complications' above.)
