Tracheostomy decannulation: what is the optimal approach?

Introduction

Patients who undergo prolonged invasive mechanical ventilation and those with the inability to maintain airway and clear secretions require tracheostomy.  A tracheostomy becomes necessary in approximately 10% of critically ill patients who require invasive mechanical ventilation.1 Once the underlying illness has resolved, the patient must be evaluated for decannulation. The ability to maintain adequate spontaneous breathing and protect the airway must be carefully assessed before deciding on decannulation. Premature decannulation can lead to serious complications including inadequate spontaneous respiratory efforts, loss of airway, and pulmonary aspiration. Inordinate delays in decannulation can also be counterproductive and predispose to late complications, including tracheal stenosis, hemorrhage, tracheomalacia, fistula formation, and infections.2  In an international survey of physicians and respiratory therapists from 118 centers across 10 countries, the key criteria for decannulation were an adequate level of consciousness, tolerance to capping of the tracheostomy tube, effectiveness of cough, oxygenation, and the quantity and character of secretions.3 Decannulation improves physical comfort, facilitates speech, and may lead to improved swallowing function.4 The approach to decannulation is the key initial step towards the rehabilitation of a patient who is on the way to recovery from critical illness and strongly influences long-term clinical outcomes. 

Weaning and liberation from mechanical ventilation 

Prior to considering decannulation, it is important to ensure the adequacy of respiratory efforts. This may be accomplished by gradually increasing the duration of unsupported breathing. Adequate humification must be ensured during this period, especially in patients with thick, tenacious secretions. A protocol-driven approach may hasten the weaning process and allow earlier liberation from mechanical ventilation.5 A gradual weaning strategy should be followed in patients with diaphragmatic dysfunction, multiorgan failure, and impaired left ventricular function.6 In a prospective cohort study, Mah et al. evaluated the efficacy of a bundled approach to post-tracheostomy care on decannulation success and improved swallowing function.7 Compared to a historical control group, a bundled approach executed by a dedicated tracheostomy service led to significantly improved decannulation rates and earlier commencement of oral diet. 

Decannulation strategies

Several techniques have been conventionally followed for the removal of tracheostomy tubes. One method involves downsizing the tracheostomy tube to a suitable size and capping it with the cuff deflated for a variable period ranging from 12–48 hours.8 However, if uncapping is required, spontaneous breathing through a narrow tracheostomy tube may cause distress as the resistance to flow is inversely proportional to the fourth power of the radius of the tube. Hence, an alternate option is single-stage decannulation without downsizing. Cohen et al. conducted a retrospective observational study that compared a single-stage decannulation protocol with a control group that underwent gradual downsizing of the tube or capping.9 Twenty-nine patients underwent single-stage decannulation, while 20 underwent traditional decannulation with downsizing and capping of the tube. There was no decannulation failure in the single-stage decannulation group; four patients in the control group experienced failure of decannulation. The duration of hospitalization was also less in patients who underwent single-stage decannulation. The authors proposed that a single-stage decannulation strategy may be safe and feasible. 

Capping techniques 

Successful decannulation requires the demonstration of the ability to breathe around the tracheostomy tube, through the natural airways. This is commonly tested by capping the tracheostomy tube after deflation of the cuff. Tolerance to capping demonstrates patency of the glottis, vocal cords, and subglottic space. The inability to phonate, development of stridor, or breathing difficulty may point towards an upper airway obstruction and necessitate endoscopic examination of the airway. If the airway appears patent on endoscopy, downsizing the tube to a suitable size will facilitate improved airflow around the capped tube.  

The alternative option is to use a one-way speaking valve at the proximal end of the tracheostomy tube, with the cuff fully deflated. During inspiration, air flows in through the speaking valve; during expiration, the speaking valve closes and airflow occurs around the tracheostomy tube through the upper airways, thus enabling speech. 

Figure 1. Airflow with a speaking valve. During inspiration, the valve opens, drawing air into the lungs. During expiration, the valve closes; air flows around the tube, through the natural airway

Capping vs. single-stage decannulation: the evidence

Protocol-based capping trials have been tested in observational studies. A capping protocol was evaluated as a quality improvement project among inpatients of a tertiary academic hospital in the US.10 The protocol was executed by a multidisciplinary team that included head and neck surgeons, anesthesiologists, respiratory therapists, and nurse practitioners. Eligible patients were screened for a capping trial and subsequent decannulation. A tracheostomy tube of size 4.0 mm internal diameter (ID) was used during the capping trial. If a 24-hour capping trial was successful, decannulation was performed. If the patients failed to tolerate the capping trial, the tracheostomy tube was opened, and recapping was attempted on the following day. During a 12-month period, 54 patients underwent the capping trial. All 50 patients who underwent a successful capping trial were decannulated successfully. In this study, the tracheostomy capping trial predicted successful decannulation with a high degree of sensitivity and specificity. Furthermore, there was a decrease in the incidence of safety concerns raised after the implementation of the protocol. 

A prospective study of patients with severe traumatic brain injury from India compared a downsizing and capping strategy with a single-stage approach to decannulation.11 In this study of 118 patients, 68 underwent downsizing and capping followed by decannulation while 50 underwent single-stage decannulation. Patients were evaluated at the end of 1 month; decannulation was considered successful among those who did not require re-tracheostomy or intubation during the follow-up period. There was no significant difference in decannulation success between the two groups (capping vs. single-stage: 98.5% vs. 94%). This study suggested that single-stage decannulation may not be inferior to a downsizing and capping strategy. 

A retrospective study of 450 patients from an acute care setting in Australia also revealed similar findings. This study compared cuff deflation trials, downsizing and capping with decannulation after 24–48 hours of cuff deflation. The incidence of recannulation was less than 3% in both groups. However, decannulation could be performed 5–6 days earlier among patients who did not undergo downsizing and capping.  

The REDECAP randomized controlled trial

The REDECAP trial was a multicenter randomized controlled trial from five ICUs in Spain that compared two different methods of decannulation. Patients were weaned off mechanical ventilation and did not require ventilator support for a 24-hour period. High-flow oxygen therapy was provided through the tracheostomy tube. A 7.0 mm ID tracheostomy tube was used in all patients. In the control group, the cuff was deflated and the tracheostomy tube capped, followed by a 24-hour trial. The capping trial was considered to have failed if uncapping was required for any reason during the trial period. Patients in the intervention group were assessed for decannulation based on the requirement for suctioning of the tracheostomy tube according to predefined indications. Decannulation was performed if the frequency of suctioning was no more than twice in 8 hours during a 24-hour period. Capping was not carried out in this group. The control group (capping trial) included 161 patients; 169 were included in the intervention group (decannulation based on suctioning frequency). Patients who underwent decannulation based on suctioning frequency were decannulated significantly earlier compared to those who underwent the capping trial [median time to decannulation: 6 (5–7) days vs. 13 (11–14 days)]. Among the secondary outcomes, the incidence of pneumonia and tracheobronchitis was lower and the duration of hospital stay shorter among patients who underwent decannulation based on the suctioning frequency. There was no difference between groups in the ICU or hospital mortality, the duration of stay in ICU or hospital, and the incidence of sepsis or multiorgan failure. 

The REDECAP trial excluded patients with anatomical abnormalities of the airway. Hence, the findings of this study are questionable among patients who have vocal cord pathology, airway narrowing, and swallowing impairment. Narrowed airways following tracheostomy may be unrecognized and lead to complications including stridor and pulmonary aspiration if abrupt decannulation is carried out with no preceding capping trial.

Endoscopic evaluation before decannulation

There is a relatively high incidence of tracheal narrowing of 20% or more in patients who undergo long-term mechanical ventilation. Formation of granulation tissue, tracheomalacia, tracheal stenosis, and vocal cord abnormalities may lead to airway obstruction after decannulation.12 Hence, a routine endoscopic inspection of the airway prior to decannulation is sometimes advocated.13 A fibreoptic bronchoscope may be introduced through a partially withdrawn tracheostomy tube and retroflexed to visualize the vocal cords from below and the trachea above the stoma. The trachea distal to the stoma is also inspected through the tracheostomy tube. The bronchoscope is inserted through the nose to visualize the vocal cords from above and the trachea above the stoma.

Rumbak et al., in a prospective observational study, performed a capping trial with an 8.0 or 7.0 mm ID tracheostomy tube after deflation of the cuff.14 All patients underwent a bronchoscopic evaluation of the airway – above the stoma by partial tube withdrawal and retroflexion and distally through the tracheostomy tube. The airway above the stoma was assessed by passing the bronchoscope through the nose. Patients who successfully completed the capping trial could be decannulated uneventfully. Those who failed had significant narrowing identified on bronchoscopy that required definitive management including tracheal resection. Although milder grades of narrowing may be observed on bronchoscopy, they are likely to be clinically relevant only if >50% of the cross-sectional area of the tracheal lumen is involved.13

Cuff deflation during weaning 

Deflation of the tracheostomy cuff during weaning trials allows airflow around the tube and increases the effective cross-sectional area of the airway. The breathing effort required for airflow through the natural airway depends on the size of the tracheostomy tube. A smaller ID offers less resistance to flow around the tube, through the natural airway. Peak flow and forced vital capacity have been shown to increase with the cuff deflated.15 Intermittent deflation of the tracheostomy cuff during spontaneous breathing trials may shorten the weaning time. Besides, the incidence of respiratory infections may be lower with improvement in swallowing function when cuff deflation is carried out during spontaneous breathing trials.16   

Key points

  • Most patients who have recovered from the underlying illness may be safely decannulated without a preceding capping trial if they are fully awake, have minimal secretions, and an effective cough. However, if the situation is unclear, with the likelihood of airway narrowing, it may be safer to consider a capping trial
  • Narrowed airways following tracheostomy may be difficult to identify; complications including stridor and pulmonary aspiration may ensue if abrupt decannulation is performed in this situation 
  • The normal tracheal diameter is 16–18 mm; resistance to airflow usually does not occur unless the diameter is narrowed to less than 50%. Hence, a capped tracheostomy tube of 7.0 mm ID or less would not normally lead to stridor unless there is tracheal narrowing. 
  • A capping trial may enhance the safety of decannulation; in case of distress, uncapping may be carried out, and ventilator support provided if necessary
  • If single-stage decannulation is carried out without a capping trial, difficulty may be encountered if reinsertion of the tracheostomy tube is required for respiratory distress. This may be particularly important in situations outside the ICU, where emergency airway access may be difficult to obtain. However, reinsertion is usually straightforward if the track is mature (beyond 2 weeks)
  • Routine bronchoscopic evaluation of the airway may not be necessary if a capping trial is carried out. A successful 24-hour capping trial usually excludes a significant degree of tracheal narrowing
  • Deflation of the cuff of the tracheostomy tube may shorten the weaning time, reduce the incidence of respiratory infections, and improve swallowing function 

References

1.         Fischler L, Erhart S, Kleger GR, Frutiger A. Prevalence of tracheostomy in ICU patients. A nation-wide survey in Switzerland. Intensive Care Med. 2000;26(10):1428-1433. doi:10.1007/s001340000634

2.         Epstein SK. Late complications of tracheostomy. Respir Care. 2005;50(4):542-549.

3.         Stelfox H, Crimi C, Berra L, et al. Determinants of tracheostomy decannulation: an international survey. Crit Care. 2008;12(1):R26. doi:10.1186/cc6802

4.         O’Connor HH, Kirby KJ, Terrin N, Hill NS, White AC. Decannulation following tracheostomy for prolonged mechanical ventilation. J Intensive Care Med. 2009;24(3):187-194. doi:10.1177/0885066609332701

5.         Medeiros GC de, Sassi FC, Lirani-Silva C, Andrade CRF de. Criteria for tracheostomy decannulation: literature review. Codas. 2019;31(6):e20180228. doi:10.1590/2317-1782/20192018228

6.         Shaikh H, Morales D, Laghi F. Weaning from mechanical ventilation. Semin Respir Crit Care Med. 2014;35(4):451-468. doi:10.1055/s-0034-1381953

7.         Mah JW, Staff II, Fisher SR, Butler KL. Improving Decannulation and Swallowing Function: A Comprehensive, Multidisciplinary Approach to Post-Tracheostomy Care. Respir Care. 2017;62(2):137-143. doi:10.4187/respcare.04878

8.         Mitchell RB, Hussey HM, Setzen G, et al. Clinical consensus statement: tracheostomy care. Otolaryngol Head Neck Surg. 2013;148(1):6-20. doi:10.1177/0194599812460376

9.         Cohen O, Tzelnick S, Lahav Y, et al. Feasibility of a single-stage tracheostomy decannulation protocol with endoscopy in adult patients: Immediate Decannulation: Feasibility and Safety. The Laryngoscope. 2016;126(9):2057-2062. doi:10.1002/lary.25800

10.       Pandian V, Miller CR, Schiavi AJ, et al. Utilization of a standardized tracheostomy capping and decannulation protocol to improve patient safety: Tracheostomy Capping and Decannulation Protocol. The Laryngoscope. 2014;124(8):1794-1800. doi:10.1002/lary.24625

11.       Shrestha KK, Mohindra S, Mohindra S. How to decannulate tracheostomised severe head trauma patients: a comparison of gradual vs abrupt technique. Nepal Med Coll J. 2012;14(3):207-211.

12.       Law JH, Barnhart K, Rowlett W, de la Rocha O, Lowenberg S. Increased frequency of obstructive airway abnormalities with long-term tracheostomy. Chest. 1993;104(1):136-138. doi:10.1378/chest.104.1.136

13.       O’Connor HH, White AC. Tracheostomy Decannulation. RESPIRATORY CARE. 2010;55(8):6.

14.       Rumbak MJ, Graves AE, Scott MP, et al. Tracheostomy tube occlusion protocol predicts significant tracheal obstruction to air flow in patients requiring prolonged mechanical ventilation. Crit Care Med. 1997;25(3):413-417. doi:10.1097/00003246-199703000-00007

15.       Hernández G, Ortiz R, Pedrosa A, et al. The indication of tracheotomy conditions the predictors of time to decannulation in critical patients. Med Intensiva. 2012;36(8):531-539. doi:10.1016/j.medin.2012.01.010

16.       Hernandez G, Pedrosa A, Ortiz R, et al. The effects of increasing effective airway diameter on weaning from mechanical ventilation in tracheostomized patients: a randomized controlled trial. Intensive Care Med. 2013;39(6):1063-1070. doi:10.1007/s00134-013-2870-7

Thirty-five Best Critical Care Blogs and Websites to follow in 2022: https://blog.feedspot.com/critical_care_blogs/

4 thoughts on “Tracheostomy decannulation: what is the optimal approach?”

  1. Thank you sir . This post is excellent and answers a lot of Frequently thought of questions. I had a doubt of feeding solids with a tracheostomy tube. Is it better/safer to keep the cuff inflated or deflated during the duration of feed ? Also, is a formal swallow assessment necessary before starting orals in all patients ?

    1. Thanks, Bhavna.

      In patients who are likely to have problems, it is best to assess swallowing before commencing an oral diet. A simple bedside test is to place 3–4 drops of methylene blue on the patient’s tongue every 6–8 hours for 24–48 hours. If the tracheal secretions have a bluish tinge, it suggests aspiration. This test may be handy in situations where a formal assessment may not be feasible. However, it is by no means an infallible testing method

      1. Thank you sir. Will try that out. It’s a very good idea. And about the cuff ? Must we leave it inflated for safety and teach patient to swallow over cuff ? Or deflate it so it is easier to swallow.

Leave a Reply