Key Point

Among ICU patients with respiratory failure, tracheostomy tube malposition is a common complication and may lead to prolonged mechanical ventilation.

Tracheostomy tube malposition is common in the ICU among patients who are being weaned from mechanical ventilation—possibly due, in part, to a lack of expertise in performing a tracheostomy among practitioners in some surgical subspecialties, said researchers in the August Chest. In their retrospective study, Ulrich Schmidt, MD, PhD, from Massachusetts General Hospital in Boston, and colleagues found that while tracheostomy tube malposition did not affect mortality outcomes, it did prolong median duration of mechanical ventilation.

WHAT DRIVES RISK OF MALPOSITION?

A total of 403 mechanically ventilated adults admitted to the respiratory acute care unit of a university-affiliated teaching hospital were included in the analysis. All had a tracheostomy tube placed during the current hospital admission. The investigators set out to determine the incidence of tracheostomy tube malposition, the patient factors and technical and mechanical tracheostomy factors associated with malposition, and the effect of tracheostomy tube malposition on various outcomes. Patient-associated factors included such things as demographics, comorbidities, and illness severity; technical and mechanical tracheostomy factors included the type of tracheostomy tube and the subspecialty of the surgeon performing the tracheostomy. The outcomes examined were length of hospital stay, length of hospital stay following tracheostomy, duration of mechanical ventilation, ICU readmission, hospital mortality, and tracheostomy tube decannulation prior to hospital discharge.

Patients underwent bronchoscopy at least once during their hospital stay. Tracheostomy tube malposition was defined as a more than 50% occlusion of the distal opening of the tracheostomy tube by tissue on bronchoscopic examination. “The types of malposition were categorized as the posterior tracheal wall occluding the distal tip of the tube, the presence of granulation tissue, tracheostomy tube too short proximally, tracheostomy tube too short distally, and tracheostomy tube cuff in the stoma,” the researchers explained.

PRACTICE MAKES PERFECT

Of the patients studied, 40 cases of tracheostomy tube malposition were found. In 23 of these cases, respiratory distress was the indication for bronchoscopy; in the remaining cases, change in respiratory mechanics was the indication. The median time from placement to identification of malposition was 12 days. The most common malposition was occlusion of the distal end of the tracheostomy tube by the posterior tracheal wall, which occurred in 37 patients. Granulation tissue, tube too short distally, cuff in stoma, and tube too short proximally accounted for six, four, three, and one case(s), respectively. Some patients had more than one type of tube malposition.

“The factor most strongly associated with tracheostomy tube malposition was the subspecialty of the surgical service of the surgeon who performed the tracheostomy,” the researchers found. General surgeons were just as likely as thoracic surgeons to be associated with a tracheostomy tube malposition (odds ratio [OR], 1.35). However, among subspecialty surgeons other than thoracic surgeons (ie, otolaryngologists, plastic surgeons, neurosurgeons, transplant surgeons, and vascular surgeons), the OR for malposition was 6.42. Based on research with regard to other surgical procedures, the investigators surmised that good patient outcomes may be related to the number of times a practitioner has performed a tracheostomy.

Mean albumin levels were slightly but significantly higher among patients with a tracheostomy tube malposition than those who did not (2.4 vs 2.1 mg/dL, respectively). “This finding is difficult to understand and does not likely reflect clinically important differences,” the researchers suggested. It is possible, though, that differences in patient anatomy and tracheostomy tube size may play a role, as the mean height of patients with a malposition was shorter (1.68 vs 1.72 m), they noted. Patient age, patient sex, severity of disease, etiology of respiratory failure, duration of mechanical ventilation, and type of tracheostomy tube or tracheostomy procedure did not appear to have an impact on risk of malposition.

Tracheostomy tube malposition was associated with a longer duration of mechanical ventilation than correct placement (25 vs 15 days, respectively). There were no significant differences in hospital mortality, length of hospital stay, ICU readmission, or the number of patients discharged to home, rehabilitation facilities, or other health care facilities.

In this study, patient factors did not strongly predict risk of malposition; therefore, it may be difficult to prospectively identify patients who are at high risk, the researchers noted. They suggested that “a high index of suspicion for tracheostomy tube malposition is required when patients demonstrate unanticipated difficulty in being liberated from mechanical ventilation following tracheostomy.”

—Adriene Marshall

Suggested Reading
Schmidt U, Hess D, Kwo J, et al. Tracheostomy tube malposition in patients admitted to a respiratory acute care unit following prolonged ventilation. Chest. 2008;134(2):288-294.

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