CORRESPONDENCE
229
To pursue this hypothesis and identify molecular susceptibility factors, we wish to institute a National Database of patients who have had severe hepatitis following exposure to an inhaled anaesthetic. We request that any practitioner having knowledge of such patients, past and present, contact us at St Mary's Hospital (letter or telephone call: (0)71 725 1681, direct line). Antibodies to TFA-modified liver proteins are detectable in about 70 % of patients with severe hepatitis and are specific to such patients. Their presence is therefore of diagnostic value and we offer an antibody-testing service to any practitioner whose patient has severe, unexplained hepatitis following exposure to a volatile anaesthetic. Although halothane is the most common cause of hepatitis, other anaesthetics are metabolized to TFA to some extent and the possibility exists that patients may become cross-sensitized to inhaled anaesthetics. We therefore wish to compile information and serum samples from all patients with unexplained hepatitis following exposure to any inhaled anaesthetic. J. G. KENNA R. M. JONES London
M. S. DHAMEE S. K. GHANDI
Wisconsin 1. Lowrie PL, Fell D, Robinson SL. Cardiovascular and plasma catecholamine responses at trachea! extubation. British Journal of Anaesthesia 1992; 68: 261-263. 2. Dhamee MS, Gandhi SK. Alterations in cardiac parameters at endotracheal extubation. Anesthesiology Review 1984; 9: 35-38. Sir,—We were not aware of the study of Dhamee and Ghandi before publication of our paper, but their points with regard to the possibility of arrhythmias at extubation are valid. However, we made no attempt to quantify the incidence of arrhythmias at extubation, as at this time all patients had received an anticholinergic, which would be expected to affect the incidence. We note that Dhamee and Ghandi also used an anticholinergic, but failed to standardize the neuromuscular blocking agent used during anaesthesia to one without cardiovascular effects. In addition, they included four patients with a history of cardiac disease. In spite of these factors, only two patients exhibited arrhythmias, and there were no significant increases in arterial pressure. Thus the residual effects of anaesthetic agents at extubation again appeared to provide a protective effect, in contrast with the situation which obtains at tracheal intubation at the onset of anaesthesia, which is associated with a greater degree of cardiac disturbance. D. FELL Leicester A. LOWRIE Manchester
Downloaded from http://bja.oxfordjournals.org/ by guest on March 22, 2016
CARDIOVASCULAR RESPONSES TO TRACHEAL EXTUBATION Sir,—We were interested in the paper by Lowrie, Fell and Robinson describing cardiovascular and plasma catecholamine responses to tracheal extubation [1]. We also had studied "alterations in cardiac parameters on endotracheal extubation" in 17 patients [2]. We exrubated the trachea of all our patients in the Post Anesthesia Recovery Unit (PACLT) and examined changes in arterial pressure, heart rate and rate-pressure product from 1 min before extubation to 1, 5, 10 and 15 min after. Our data also showed no significant change in systolic and diastolic arterial pressure. Five minutes after tracheal extubation, the heart rate had decreased significantly and remained reduced at 10 and 15 min, although it was unchanged at 1 min. We did not use laryngoscopy before extubation. In addition, we did not observe any cardiac arrhythmias in 15 of the 17 patients. The remaining two who had ventricular premature beats before and during surgery had similar character-
istics and frequency after extubation. From the small size of our sample population, we could state that, at the 95% confidence level, the probability of occurrence of arrhythmias on tracheal extubation would be less than 19.5 %. Lowrie, Fell and Robinson did not mention the incidence of arrhythmia in their study patients. Although the incidence of arrhythmia seems to be smaller at extubation than at intubation, it could still be harmful in certain patient populations. We now routinely monitor the ECG in the PACU.
229
To pursue this hypothesis and identify molecular susceptibility factors, we wish to institute a National Database of patients who have had severe hepatitis following exposure to an inhaled anaesthetic. We request that any practitioner having knowledge of such patients, past and present, contact us at St Mary's Hospital (letter or telephone call: (0)71 725 1681, direct line). Antibodies to TFA-modified liver proteins are detectable in about 70 % of patients with severe hepatitis and are specific to such patients. Their presence is therefore of diagnostic value and we offer an antibody-testing service to any practitioner whose patient has severe, unexplained hepatitis following exposure to a volatile anaesthetic. Although halothane is the most common cause of hepatitis, other anaesthetics are metabolized to TFA to some extent and the possibility exists that patients may become cross-sensitized to inhaled anaesthetics. We therefore wish to compile information and serum samples from all patients with unexplained hepatitis following exposure to any inhaled anaesthetic. J. G. KENNA R. M. JONES London
M. S. DHAMEE S. K. GHANDI
Wisconsin 1. Lowrie PL, Fell D, Robinson SL. Cardiovascular and plasma catecholamine responses at trachea! extubation. British Journal of Anaesthesia 1992; 68: 261-263. 2. Dhamee MS, Gandhi SK. Alterations in cardiac parameters at endotracheal extubation. Anesthesiology Review 1984; 9: 35-38. Sir,—We were not aware of the study of Dhamee and Ghandi before publication of our paper, but their points with regard to the possibility of arrhythmias at extubation are valid. However, we made no attempt to quantify the incidence of arrhythmias at extubation, as at this time all patients had received an anticholinergic, which would be expected to affect the incidence. We note that Dhamee and Ghandi also used an anticholinergic, but failed to standardize the neuromuscular blocking agent used during anaesthesia to one without cardiovascular effects. In addition, they included four patients with a history of cardiac disease. In spite of these factors, only two patients exhibited arrhythmias, and there were no significant increases in arterial pressure. Thus the residual effects of anaesthetic agents at extubation again appeared to provide a protective effect, in contrast with the situation which obtains at tracheal intubation at the onset of anaesthesia, which is associated with a greater degree of cardiac disturbance. D. FELL Leicester A. LOWRIE Manchester
Downloaded from http://bja.oxfordjournals.org/ by guest on March 22, 2016
CARDIOVASCULAR RESPONSES TO TRACHEAL EXTUBATION Sir,—We were interested in the paper by Lowrie, Fell and Robinson describing cardiovascular and plasma catecholamine responses to tracheal extubation [1]. We also had studied "alterations in cardiac parameters on endotracheal extubation" in 17 patients [2]. We exrubated the trachea of all our patients in the Post Anesthesia Recovery Unit (PACLT) and examined changes in arterial pressure, heart rate and rate-pressure product from 1 min before extubation to 1, 5, 10 and 15 min after. Our data also showed no significant change in systolic and diastolic arterial pressure. Five minutes after tracheal extubation, the heart rate had decreased significantly and remained reduced at 10 and 15 min, although it was unchanged at 1 min. We did not use laryngoscopy before extubation. In addition, we did not observe any cardiac arrhythmias in 15 of the 17 patients. The remaining two who had ventricular premature beats before and during surgery had similar character-
istics and frequency after extubation. From the small size of our sample population, we could state that, at the 95% confidence level, the probability of occurrence of arrhythmias on tracheal extubation would be less than 19.5 %. Lowrie, Fell and Robinson did not mention the incidence of arrhythmia in their study patients. Although the incidence of arrhythmia seems to be smaller at extubation than at intubation, it could still be harmful in certain patient populations. We now routinely monitor the ECG in the PACU.
