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Does tracheostomy improve respiratory functions in mechanically ventilated patients


Tracheostomy has been widely performed in the intensive care unit and has many advantages when compared with translaryngeal intubation. Our hypothesis was that tracheostomy would also result in improved pulmonary function through changes in respiratory mechanics and tracheabronchial touilette.

Study design

A prospective, observational, clinical study. A before-and-after trial of 65 patients undergoing tracheostomy.

Patients and methods

A consecutive group of critically ill patients requiring prolonged mechanical ventilation was included in the study (15 July 2004–1 December 2004). Percutaneous tracheostomy was performed using the dilatational forceps technique described by Griggs. Respiratory mechanics (ventilator settings, airway pressures) and arterial blood gases (PaO2, PaCO2, pH) were measured before and after tracheostomy (at 24, 48 and 72 hours) in 65 patients. Calculated variables included minute ventilation, dynamic and static compliances and PaO2:FiO2 ratio (Harowitz).


A total of 65 patients (with a mean age of 50.6 ± 20 years) underwent tracheostomy a mean of 5 ± 2.6 days after admission. The Glasgow Coma Scale score and Acute Physiology and Chronic Health Evaluation II score were 8.3 ± 3.7 and 20.61 ± 5.3, respectively. We could not find statistically significant differences in respiratory mechanics, blood gases and pH after tracheostomy when we considered all of the patients. Then, we evaluated the results by dividing the patients into two groups according to the Harowitz ratio. Forty-three patients had Harowitz ratio greater than 250 (396.5 ± 105.5) and 22 patients less than 250 (201.1 ± 36.5). Both groups were analyzed with repeated-measures analysis of variance and we found that the Harowitz ratio at 24 hours (265.3 ± 71), 48 hours (269 ± 26) and 72 hours (274 ± 93) improved significantly after tracheostomy individually (P = 0.002, P = 0.018, P = 0.004, respectively) in the patients with a Harowitz ratio less than 250.


Our study showed that percutaneous tracheostomy improves the PaO2:FiO2 (Harowitz) ratio in the mechanically ventilated patients who had Harowitz ratio less than 250 before tracheostomy, but does not improve it in the patients with Harowitz ratio greater than 250.

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Akin, F.P., Dösemeci, L., Cengiz, M. et al. Does tracheostomy improve respiratory functions in mechanically ventilated patients. Crit Care 9, P117 (2005).

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  • Intensive Care Unit
  • Airway Pressure
  • Glasgow Coma Scale
  • Health Evaluation
  • Respiratory Function