Hypercarbia During Tracheostomy in the Head-Injured Patient: Compariscon of Percutaneous Endoscopic, Percutaneous Doppler and Standard Tracheostomy

Abstract

Purpose: Bronchoscopy during percutaneous tracheostomy may cause a significant increase in pCO2 due to hypoventilation. The clinical relevance of this hypercarbia is unclear. We examined the effects of procedure-induced hypercarbia on cerebral perfusion during percutaneous endoscopic (PET), percutaneous doppler (PDT), and standard surgical tracheostomy (ST). Methods: Three patients with indwelling radial artery catheters and intracranial pressure monitors underwent PET, PDT, or ST in the Intensive Care Unit. Intermittent arterial blood gases were obtained throughout each procedure. Simultaneous measurements of mean arterial pressure (MAP), intracranial pressure (ICP), and cerebral perfusion pressure (CPP=MAP-ICP) were recorded. Results: All tracheostomies were successfully performed with no technical complications. No episodes of hypoxia occurred during the procedures. Conclusions: Bronchoscopy during percutaneous endoscopic tracheostomy leads to hypoventilation, hypercarbia, and respiratory acidosis. In the head-injured patient, this hypercarbia does result in a marked increase in ICP and a related decrease in CPP to ischemic ranges. Tracheostomy (either standard surgical or percutaneous using the doppler ultrasound to position the endotracheal tube) can be safely performed in the head injured patient without adversely affecting cerebral perfusion. The potential for hypoventilation should be considered when choosing the method of tracheostomy in the head-injured patient where hypercarbia may be detrimental to cerebral hemodynamics. CORRESPONDENCE Patrick M. Reilly, M.D. Division of Trauma and Surgical Critical Care Department of Surgery University of Pennsylvania School of Medicine 3440 Market Street First Floor Philadelphia, PA 19104 (215) 662-7320 (215) 349-5917 FAX E-mail: reillyp@mail.med.upenn.edu