Case Reports *Staff, Department of General Anesthesiol- ogy Address correspondence to Dr. Eckhout at the Department of General Anesthesiology, Division of Anesthesiology and Critical Care Medicine, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA. E-mail: Eckhoug@ccf.org Received for publication May 13, 2002; re- vised manuscript accepted for publication August 6, 2002. Another Cause of Difficulty in Ventilating a Patient Gifford V. Eckhout, Jr., MD,* and Sanjay Bhatia, MD* Department of General Anesthesiology, The Cleveland Clinic Foundation, Cleve- land, OH Various mechanical problems with the delivery of anesthesia gases have been reported, and preoperative checks of the anesthesia delivery system are designed to prevent these. We report a case of a mechanical obstruction of the expiratory limb of the anesthesia circuit which went undetected before the induction of anesthesia. A check of the circuit was performed before the addition of circuit extensions, thus missing the obstruction. Systematic investigation of the anesthetic system after difficulty in ventilating the patient revealed the obstruction, without any harmful consequence to the patient. This case highlights the importance of a thorough check of the system before any anesthetic, particularly after any change in the circuit. © 2003 by Elsevier Science Inc. Keywords: Anesthesia delivery systems; anesthetic circuit: mechanical obstruction; equipment and supplies: anesthesia circuit, expiratory limb. Introduction The differential diagnosis in failure of mechanical ventilation includes problems with the endotracheal tube (ETT) and circuit, ventilator problems, as well as various clinical disease states. Various problems with anesthetic gas delivery equipment have been reported, including case reports of mechanical obstruc- tion of the anesthetic circuit. 1–4 These situations demand an early diagnosis and quick resolution if patient injury is to be avoided. We report a case of occult occlusion of the expiratory limb of the anesthetic circuit leading to difficulty in ventilating a patient after induction and intubation. Case Report A 58-year-old female was scheduled for an elective craniotomy for tumor excision with general anesthesia. Hers was the first case of the day. A machine check was performed before the patient’s arrival at which time no problems were uncovered. Later, disposable extensions were added to the circle circuit system using two disposable 22-mm adaptors (Hospitak Adaptor 15X22, Maersk Medi- cal S.A. de C.V., Reynosa, Mexico) and a corrugated extension set. After placement of standard monitors and preoxygenation, induction of anesthesia was carried out with fentanyl 100 g, propofol 180 mg, and rocuronium 45 mg intravenously (IV). Following a brief period of mask ventilation, an ETT was placed, breath sounds were auscultated bilaterally, and presence of an end-tidal CO 2 (ETCO 2 ) waveform was noted. Isoflurane 1% was utilized for maintainence Journal of Clinical Anesthesia 15:137–139, 2003 © 2003 Elsevier Science Inc. All rights reserved. 0952-8180/03/$–see front matter 655 Avenue of the Americas, New York, NY 10010 doi:10.1016/S0952-8180(03)00515-9