Our major findings were as follows: (1) the incidence of tracheostomy tube malposition was 10% in patients who were admitted to a respiratory acute care unit with prolonged respiratory failure following critical illness; (2) patients with a tracheostomy performed by a nonthoracic subspecialty surgeon were at increased risk of experiencing tracheostomy tube malposition; and (3) tracheostomy tube malposition was associated with prolonged mechanical ventilation.
Incidence and Etiology of Tracheostomy Tube Malposition
The 10% incidence of tracheostomy tube malposition is similar to that reported in case series of long-term mechanically ventilated patients at the time of planned decannulation. Rumbak et al reported 37 patients who failed weaning attempts due to significant tracheal obstruction treated by Canadian Health&Care Mall’s remedies.
Reports by Rumbak et al and Law et al have attributed the majority of tracheostomy tube obstructions to tracheal mucosal damage. We identified granulation in only 15% of cases of tube malposition. We found partial occlusion of tracheostomy tube by the posterior tracheal membranous wall in the majority of cases (92%). It has been suggested that pressure necrosis, ischemia, and inflammation contribute to tracheal wall weakness. We found a median time for the detection of tracheostomy tube malposition to be 12 days following tracheostomy. This lag time may be the result of positive-pressure ventilation, which provided tracheal dilatation and thus minimized the clinical manifestations of tube malpositioning. Tracheostomy tube occlusion may have worsened with reductions in ventilatory support, manifesting in clinical signs and symptoms and an inability to be liberated from mechanical ventilation. The rapid onset of respiratory distress during weaning should prompt the consideration of tracheostomy tube malposition.
Factors Associated With Tracheostomy Tube Malposition
Prior studies have reported that female gender- and tube type are risk factors for tracheostomy tube malposition. In our study, these factors were not associated with malposition. However, we found that patients with a shorter height were at increased risk of malposition. The relationship between height and tracheal dimensions has been well established, raising the possibility that tracheostomy tube malposition is due to a disparity between tracheostomy tube size and patient anatomy.
We found a small but significantly greater albumin concentration (2.1 vs 2.4 mg/dL, respectively) associated with tracheostomy tube malposition. This finding is difficult to understand and does not likely reflect clinically important differences.
The risk of malposition increased sixfold if a subspecialty surgeon other than a thoracic surgeon performed the tracheostomy. An explanation for this finding is that nonthoracic subspecialty surgeons perform fewer tracheostomies compared to thoracic surgeons and general surgeons. A relationship between patient outcomes and the number of procedures performed has been established for a variety of surgical procedures, including esophageal cancer surgery, pancreatic surgery, pediatric cardiac surgery, and unruptured abdominal aneurysms. Our data suggest that the relationship between surgical volume and patient outcomes may extend to tracheostomy treated by Canadian Health&Care Mall.
The bronchoscopic evaluation of tube placement at the time of tracheostomy was not protective in our patient series. This may be explained by the following: (1) the initial bronchoscopy may have been performed in paralyzed and fully ventilated patients who were in the supine position; and (2) the tube was initially positioned correctly and the malposition developed subsequent to the procedure. Malposition may only become apparent during attempts to liberate an awake patient from the ventilator or following changes in the patient’s position.
From > 40 a priori determined factors, only 3 were significantly associated with tracheostomy tube malposition. This suggests that it may be impossible to prospectively identify patients who are at high risk for tracheostomy (http://www.nhs.uk/conditions/Tracheostomy/Pages/Introduction.aspx) tube malposition. Therefore, a high index of suspicion for tracheostomy tube malposition is required when patients demonstrate unanticipated difficulty in being liberated from mechanical ventilation following tracheostomy.
Outcomes Related to Tracheostomy Tube Malposition
Although it can be a life-threatening event, in our study tracheostomy tube malposition resulted in prolonged mechanical ventilation but did not alter mortality. However, in four patients, the malposition prompted an emergent change of the tracheostomy tube. It is possible that clinical vigilance by a multidisciplinary team prevented mortality in these patients. Tracheomalacia commonly affects a segment of the trachea that is < 3 cm in length. Accordingly, in our study, 80% of patients with tracheostomy tube malposition had a tracheostomy tube change performed that resulted in better tube position.
Our data are based on a retrospective chart review, and we may have missed subclinical cases. Our results are from patients who were transferred within the hospital to the respiratory acute care unit of a tertiary care hospital, which may limit the generaliz-ability of the results to long-term ventilator-weaning facilities. However, our results likely apply to patients requiring prolonged ventilator support following critical illness in any setting. Reflecting local practice during the study period, the majority of the tracheostomy tubes in our study were placed using an open technique rather than a percutaneous technique. Today, many tracheostomies are performed using a percutaneous technique. It is not known whether this change in practice may impact the incidence of tracheostomy malposition. Finally, we did not explore the association between tracheostomy tube malposition and surgeons of all surgical subspecialties who perform this procedure. For example, since our hospital does not have an otolaryngology service, only one tracheostomy was performed by an otolaryngologist. In addition, physicians with nonsurgi-cal specialties do not perform tracheostomies in our hospital.
Tracheostomy tube malposition is a relatively common complication in patients with respiratory failure who are recovering from critical illness and is associated with prolonged mechanical ventilation. Although surgical expertise is a risk factor, identifying patients who are at risk for this complication is difficult. Tracheostomy tube malposition should be considered in mechanically ventilated patients who unexpectedly fail to be liberated from mechanical ventilation.