key: cord-0987232-hn0hh1cl
authors: Ting, Chien-Kun; Liu, Hsu-Tang; Chen, Kung-Yen; Liu, Chen-Kou; Tsou, Mei-Yung; Chan, Kwok-Hon; Tsai, Shen-Kou
title: Using a CO(2) detector to confirm endotracheal intubation in SARS patients
date: 2005
journal: Can J Anaesth
DOI: 10.1007/bf03016300
sha: d57ab6f1c52ba6f09f2bb303cf5243e6ba264157
doc_id: 987232
cord_uid: hn0hh1cl

nan

To the Editor: Severe acute respiratory syndrome (SARS) is a new respiratory viral epidemic with devastating impact on economics and the practice of medicine. 1 SARS struck Taiwan in the Spring of 2003, causing many deaths, serious morbidity and closure of provincial hospitals. The high infectious rate by droplet transmission places anesthesiologists at a substantial risk during tracheal intubation. Two physicians were infected during intubation resulting in mortality at the early stage of SARS in Taiwan. In addition to wearing personal protective equipment (PPE), using powered air purifying respirators (PAPR) during tracheal intubation can completely eliminate SARS-CoV contamination. PPE consisted of double gowns, double gloves, Tyvek hood (Texas America Safety Company, Brownwood,  TX, USA), N95/100 mask (3M, Taipei, Taiwan),  goggles and face shield. However, wearing PPE with PAPR renders the user with impaired hearing, vision and communication. Verifying correct tracheal intubation by using a stethoscope for auscultation became difficult. There were 31 SARS patients who required tracheal intubation for mechanical ventilation at the Taipei-Veterans General Hospital. A total numbers of 37 intubations were performed because four patients had double intubations and one patient had triple intubations. In order to prevent cough with high viral content during intubation, after preoxygenation the tracheal intubation was facilitated by iv administration with propofol and succinylcholine. We then connected the disposable colorimetric end-tidal CO 2 detector (the Nellcor® Easy Cap™ II) to the endotracheal tube to verify the correct endotracheal tube placement.

The CO 2 detector device (the Fenem FEF™ CO 2 detector) was first introduced for confirmation of tracheal intubation in 1988. 2 It is a small, portable plastic attachment connected between the tube and catheter mount of the breathing system. It is also a semi-quantitative capnometer devoid of electronics. The EasyCap™ II detector detects carbon dioxide in exhaled gases via a chemical coloured membrane and changes colour from purple to yellow. Such a change indicates the presence of CO 2 in the exhaled gas which passes. In our experience, the colour of the colorimetric end-tidal CO 2 detector changed from purple to yellow within six cycles of breathing ventilated by ambu-bagging after endotracheal intubation in SARS patients.

None of the anesthesiologists who performed the intubation procedure under the guideline was infected. The use of the disposable colorimetric end-tidal CO 2 detector could be a simple and reliable way of confirming correct tracheal intubation in SARS patients while wearing PPE with PAPR. 

To the Editor: A 61-yr-old male patient was scheduled for open retropubic prostatectomy. Medical history consisted of arterial hypertension and ischemic cardiopathy treated medically (nitrates and diltiazem chlorhydrate). Preoperatively, the patient did not complain of chest pain and functional capacity was good. Physical examination, resting electrocardiography and usual preoperative blood tests were normal. The patient did not take his morning diltiazem, arriving to the operating room 36 hr after his last dose. Induction of anesthesia was achieved by iv propofol, sufentanil, and rocuronium. Maintenance of anesthesia was with inhaled sevoflurane (1-2% end-tidal) and iv boluses of sufentanil and rocuronium as needed. Surgery was uneventful. On PACU arrival, the patient was fully awake, responsive and free of pain. Systemic blood pressure was 118/66 mmHg, heart rate 62 beats·min -1 , and pulse oximetry 99%. A few minutes later, the patient developed ventricular fibrillation (VF). He was resuscitated as per the Adult Advanced Cardiac Life Support algorithm. 1 During the next hour, episodes of VF occurred inducing hemodynamic instability. The 12-lead electrocardiogram recorded during normal sinusal rhythm showed diffuse and massive ST-segment elevation. Cardiac catheterization was decided. During the transfer, he developed electromechanical dissociation and despite adequate resuscitation, the patient remained 30 min without a detectable pulse. After a last 1 mg administration of epinephrine, the heart rate normalized. The coronary angiogram showed a severe, diffuse coronary spasm, leading to the diagnosis of variant angina. Intracoronary nitroglycerin immediately relieved the spasm, uncovering a normal coronary anatomy. The patient made a rapid recovery. This case is illustrative of possible causes of VF in the PACU: coronary spasm due to undiagnosed variant angina or acute withdrawal of calcium-channel blockers.

This makes the preoperative interview and maintenance of usual medications crucial. A clear diagnosis is sometimes difficult during resuscitation. Epinephrine can induce a vicious circle making further therapeutic decisions difficult, 2 while nitrates or calcium-channel blockers are not always easy, straightforward, therapeutic choices during persistent VF.

The diagnosis of variant angina is not always easy to make preoperatively. 3, 4 This condition is probably under diagnosed in the surgical population. A patient with an unclear coronary history developing VF in the perioperative period must undergo rapid coronary angiography to make the difference between "classic" atheromatous coronary disease and variant angina. Moreover it allows specific treatment: coronary angioplasty with or without stenting or intracoronary nitrate injection.

Jean-Corentin Salengros MD Pierre Pandin MD Edgard Engelman MD CUB Hôpital Erasme, Brussels, Belgium E-mail: Jean-Salengros@ulb.ac.be

Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular care: Part 6: advanced cardiovascular life support: 7C: a guide to the International ACLS algorithms. The American Heart Association in collaboration with the International Liaison Committee on Resuscitation

Coronary artery spasm induced by intravenous epinephrine overdose

Organic coronary stenosis in Prinzmetal's variant angina

Management of unexpected coronary artery spasm in an asymptomatic patient during anaesthesia