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Abstract

Introduction: A patient’s ability to protect and maintain the airway with an effective cough remains an important aspect of pre-extubation assessment. A standardized assessment or measurement of an effective cough mechanism remains elusive. Intra-abdominal pressure (IAP) may serve as a surrogate for cough effectiveness, muscle strength, and success of extubation. Hypothesis: The aim of this study is to determine if IAP can be measured on mechanically ventilated patients prior to extubation during voluntary and involuntary cough. Methods: This study is a prospective cohort study of endotracheally intubated mechanically ventilated patients in a medical surgical intensive care unit (ICU). Patients passed a spontaneous breathing trial (SBT) according to an existing weaning protocol. The IAP was measured using the Abviser (WolfeTory Medical, Inc., Salt Lake City, UT) collecting baseline, voluntary cough, and involuntary cough pressures recorded from a bedside monitor. The patient was positioned in a semi recumbent state for the measurements. The voluntary cough was simply performed by asking the patient to cough and the involuntary cough was induced by advancing the closed system suction catheter similar as if the patient was undergoing standard suctioning procedure. Successful extubation was defined as remaining extubated for at least 48 hours. Results: Twelve patients with an average age of 65 +/- 17 years, 5 males and 7 females were enrolled. Endotracheal tube sizes were four 8 mm and eight 7.5 mm and the average days of mechanical ventilation was 5 +/- 4. The baseline IAP was 10 +/- 6 mmHg. Increase IAP with voluntary cough was 46 +/- 20 mmHg and with involuntary cough was 97 +/- 37 mmHg. Twelve patients were successfully extubated. Conclusions: Measuring IAP at baseline, during voluntary and involuntary cough was easily accomplished on mechanically ventilated patients prior to extubation. These pilot data provide baseline measurements for ongoing study of this technique. Larger studies are required to determine the level of IAP that may be clinically useful to predict extubation success and airway maintenance.