Robert G. Hooper

Massive airway leaks : an analysis of the role of endotracheal tubes

ObjectiveTo determine the abnormalities present in endotracheal tubes removed from mechanically ventilated patients for “massive airleak,” “Massive airleak” was defined as a leak that the attending physician felt was indicative of endotracheal tube defect such that extubation (and reintubation, if needed) would be indicated. DesignProspective, observational study. SettingMixed medical-surgical intensive care unit at a community teaching hospital. PatientsSeventeen patients among 1,082 patients who were undergoing mechanical ventilation during the study period. InterventionsAuthors were not involved in the evaluation of most airleak situations and most participating physicians were unaware of the study. All physicians involved were board certified in pulmonary, critical care, emergency medicine, or anesthesiology. Removed endotracheal tubes were grossly inspected and subjected to pneumatic stress to determine the sites of the leakage. Measurements and Main ResultsEighteen endotracheal tubes were examined over a 2-yr period. Of these tubes, 11 (61%) had no evidence of mechanical fault. Five (28%) tubes had defects in the tracheal cuff and two (11%) tubes had abnormalities of the pilot valve apparatus. Condensation within the pilot valve cuff was present in 14 of 18 tubes and was present in ten of 11 intact tubes. Although the study population had an equal number of orally and nasally placed endotracheal tubes, intact tubes were disproportionately oral (8/11) and tubes with cuff leaks were predominantly nasal (4/5) (p = .038). ConclusionsA large number of endotracheal tubes removed for presumed defect are flawless. The authors speculate that tube malposition is the most likely explanation for this phenomenon. Our findings suggest that patient care might improve with more meticulous daily attention to the airway, as well as a more analytical rather than action-oriented approach to the leaking endotracheal tube. (Crit Care Med 1993; 21:518–521)

Systolic Time Intervals in Chronic Obstructive Pulmonary Disease

In an attempt to clarify the relationship between left ventricular function and chronic obstructive pulmonary disease (COPD), systolic time intervals (STI) were measured in 12 control subjects and 28 patients with COPD who had only moderate arterial blood gas abnormalities and who had no cardiac symptomatology or clinical evidence of organic heart disease. The patients with COPD were divided into three groups of increasingly severe airway obstruction based on the percent predicted forced expired volume in one second.Significant differences in pre-ejection period index (PEP1) and left ventricular ejection time index (LVET1) existed between the control subjects and the patients with the most severe lung disease (Group III). A highly significant difference in PEP/LVET existed between these two groups. The abnormalities of STI demonstrated in these patients are characteristic of left ventricular dysfunction and indicate that subclinical left ventricular dysfunction is frequently present in patients with moderate obstructive lung disease.