LIVER FUNCTION TESTS FOLLOWING ANAESTHESIA

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1 Br.J. Anaesth. (),, 5 LIVER FUNCTION TESTS FOLLOWING ANAESTHESIA J. MCEWAN SUMMARY Liver function tests were performed in 41 patients who required repeated anaesthetics for genitourinary surgery, and who had received multiple halothane anaesthetics in the past, first following anaesthesia using halothane and then following an anaesthetic without halothane. There was a smaller frequency of disturbance of liver function after halothane than after the non-halothane anaesthetic. There was no obvious relationship between the number of anaesthetics, or the total duration of anaesthesia, and the disturbance of liver function tests. Early studies of liver function tests showed no greater frequency of abnormality in a halothane series compared with a control series (Burns et al., 5); however, there have been many subsequent reports of jaundice following the use of halothane. The large retrospective study in the U.S.A. (National Halothane Study, ) has been subjected to many interpretations, and various sections have been used to support opposing arguments. Further information on "halothane hepatitis" has been published by Moult and Sherlock (5), Simpson, Strunin and Walton (5), and reviewed by Virtue (5). Following the circular from the sub-committee on adverse reactions of the Committee on Safety on Medicines (Mansell-Jones, 4), controlled studies on the effects of repeated halothane anaesthetics have been reported from Oxford (Trowell, Petro and Crampton-Smith, 5) and Southampton (Wright et al., 5). However, the question remains unanswered as to whether or not halothane is an acceptable agent for repeated use, and if so, what safeguards can be taken to minimize the chances of hepatic necrosis. The present study was designed to compare the effects on liver function, in subjects who have previously had multiple halothane anaesthetics, of anaesthesia with halothane, followed on a separate occasion by a non-halothane anaesthetic. PATIENTS AND METHODS The study commenced in September 4. All the patients were males, retired or serving members of Her Majesty's Forces attending hospital for repeated trans-urethral surgery. A full anaesthetic history was JAMES MCEWAN, M.B., CH.B., F.F.A.R.C.S., Queen Alexandra Military Hospital, Millbank, London. obtained and the object of the study was explained to each patient by the author. On the morning of operation, with the patient in the rested fasting state, venepuncture was performed using gravity or minimal and brief constriction of the limb, to distend the vein. Blood was taken into a heparinized tube for liver function tests, and an EDTA tube for haematological examination. The heparinized blood was centrifuged and the plasma was separated with the minimum delay, to avoid leakage of enzymes from the erythrocytes. Following operation, at the same time of day, and with the patient again in the resting fasting state, blood was sampled as before. If the patient remained in hospital, this was repeated during his stay, under identical conditions, the highest value after operation being taken for the results tables. Since patients came from a wide area (including one retired officer from Teneriffe) routine outpatient follow-up was not attempted. However, two patients were recalled because of the particular nature of their results (nos 1 and ). On the first occasion the anaesthetic consisted of a sleep dose of thiopentone followed by % nitrous oxide in oxygen and halothane 1-% reducing to 0.5-1% by mask using a Mapleson "A" circuit. The non-halothane anaesthetic consisted of a similar induction with thiopentone followed by gallamine 80 mg and ventilation with nitrous oxide.5 litre/min and oxygen.5 litre/min using an East Autovent non-rebreathing circuit, with apparatus free of halothane. In a few instances atropine and neostigmine were used to restore neuromuscular conduction. In both procedures, premedication was with papaveretum and hyoscine; all patients received oxygen from a disposable mask for min after operation.

2 BRITISH JOURNAL OF ANAESTHESIA LABORATORY METHODS The liver function tests used routinely in the Queen Alexandra Military Hospital are serum concentrations of bilirubin, total protein, albumin, alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase (s.g.o.t.) and alanine aminotransferase (s.g.p.t.). Except for the protein estimation, these are performed using a Technicon Auto Analyzer Mark II using the method of Levine and Hill modified by Rush, Leon and Kessler (0) for aminotransferases, Morgenstern and colleagues (5) for alkaline phosphatase and lactate dehydrogenase, and Jendrassik TABLE I. Aspartate PreH aminotransferase and alanine aminotransferase values (iu) before and after two anaesthetics (H = halothane; O = non-halothane) Aspartate aminotransferase PostH PreO Post O PreH PostH Alanine aminotransferase PreO Post O Aspartate aminotransferase s: f = 1., P = Log ratios: t = 1., />=0 03. Wilcoxon Signed Rank Test: Z= -.80, P = Alanine aminotransferase s: t= 1., P = Log ratios: t= 1.01, P=0.05. Wilcoxon Signed Rank Test: Z= -0.81, P = 0.(n.s.)

3 LIVER FUNCTION TESTS AFTER ANAESTHESIA and Grof () for bilirubin. Every th sample is a control, and, as a further check on accuracy, the laboratory uses the Wellcome Quality Control Service. All specimens are entered in duplicate. A pilot study in September 4, to find the optimum storage conditions for samples, established that only minimal changes occurred after storage at room temperature for up to 3 days. RESULTS Except for patient no. 1, alkaline phosphatase values were virtually unchanged. Patients 1, and had increased bilirubin values, and altered albumin/ globulin ratios, and will be discussed separately. The results for lactate dehydrogenase (LDH) were tabulated but are not presented in detail. The aminotransferase values are shown in table I. The postoperative/preoperative ratio was taken as the basis for statistical comparison, as in the Oxford and Southampton studies. Applying Student's t test to the actual ratios, the non-halothane anaesthetic was found to be associated with an increase more often than could be expected by chance (s.g.o.t.: t= 1.8; P = 0.05; s.g.p.t.: t = 1.; P= 0.05). Using the Naperian logarithms of the ratios, the statistical significance of the difference remained (P = 0.03 for s.g.o.t.; P = 0.05 for s.g.p.t.). Using the Wilcoxon Rank Order test and the Wilcoxon Signed Rank test, the increase in s.g.o.t. was significant (P = 0.00) but that for s.g.p.t. was not. The numbers of patients in whom enzymes were increased and were above normal after operation are classified in table II. Following both anaesthetics increases in s.g.o.t. in six patients and s.g.p.t. in four patients were noted. Additional analyses are shown in table III. No patient showed pyrexia or eosinophilia after operation, and none was a positive reactor for Australia antigen, antibody or antigen-antibody complex. The results after operation are shown in figures 1 and in the form of histograms, to attempt to illustrate TABLE II. Increases beyond normal values after operation Enzymes Halothane Non-halothane LDH, s.g.o.t., s.g.p.t. 1, s.g.p t. 4 LDH only only S.g.p.t. only 3 5 TABLE III. Change in enzyme concentrations within the "normal" range after operation Change in Non- Enzyme concentration Halothane halothane + s.g.p.t. + s.g.p.t. S.g.p.t. S.e.p.t. S.g.p.t. Decrease None Decrease Decrease None None Increase Increase Time (days) FIG. 1. Halothane series (eight patients). The timing of highest values where more than one sample was taken. 5 I 4 I 3 _ _ S.g.p.t. n I Time (days) FIG.. Non-halothane series ( patients). The timing of highest values where more than one sample was taken. the time sequence where more than one result was taken after operation. In the cases under study the highest value was usually that taken on the day after the anaesthetic. Patients 1, and were of special interest. Patient no. 1, a retired officer, aged 8 yr, had developed a deep vein thrombosis which persisted for some months and was present at the time of entry to the study. He lived an outdoor life and his bilirubin concentration of 51 (imol/litre had passed unnoticed. He felt in good health. After anaesthesia with halothane for a large recurrence of a cauliflower-like papilloma of the bladder (a procedure lasting more than 1 h) s.g.o.t., s.g.p.t. and LDH were all increased. Six weeks later these had returned to almost the

4 8 BRITISH JOURNAL OF ANAESTHESIA value before operation when he had a short anaesthetic for cystoscopy at the Royal Naval Hospital, Haslar. On that occasion he received halothane also. On this occasion the enzymes were unchanged. Six weeks later the aminotransferase concentrations were within normal limits but the alkaline phosphatase had increased to twice the upper limit of normal. The next anaesthetic did not include halothane and was followed by a seven-fold increase in s.g.o.t., and a three-to-four-fold increase in s.g.p.t. and in LDH. The alkaline phosphatase concentration remained increased but less than previously and the bilirubin concentration increased again to 4. (xmol/litre having been. (jimol/litre before operation. A liver biopsy showed acute continuing chronic hepatitis. The patient continues to attend for treatment for his carcinoma, feeling fit and well. Patient no., a serving soldier with hepatitis which was related to his alcohol consumption and which was confirmed by liver biopsy. Liver function tests are now normal and remain so with halothane anaesthesia, but show a mild increase with nonhalothane anaesthesia. Patient no., a retired naval officer, aged 3 yr, with a history of arterial hypertension, cardiac failure and alcohol-induced liver disease. At present he has chronic liver disease unaffected by halothane but with an increase in s.g.p.t. after non-halothane anaesthesia. DISCUSSION The patients in this study received an anaesthetic which included halothane, followed by a nonhalothane anaesthetic; there was no attempt at randomization. This was deliberate and avoided the need for discussions on the ethics of the study the "routine" method being tested first, followed by another method which was tried to determine which was better. This is no sophist argument, since the results have influenced our decisions regarding anaesthesia for patients who have been treated since the study was completed. The biochemical values before operation were unknown at the time of operation, so those patients with liver dysfunction before surgery were undetected, and received halothane in a situation which some anaesthetists would consider to have been inappropriate. The results of this study suggest that the response to anaesthesia alters as a function of the number of anaesthetics received by a patient; also the time to response shortens. This supports the findings of the Oxford and Southampton studies, and as regards timing, the studies of Moult and Sherlock (5). However, it is interesting to note that s.g.o.t. and s.g.p.t. changed in opposite directions in patients in the halothane series (by appreciable amounts in three) and in patients in the non-halothane series (by appreciable amounts in five). Patient no. 1 (second anaesthetic), patient no. (first anaesthetic) and patient no. (both anaesthetics) cast doubt on the prognostic value of preoperative tests, as high values are not always followed by an increase in the enzyme concentrations, nor are low values indicative of safety. This study indicates that where patients have previously had more than four halothane anaesthetics, it may be less upsetting to liver function to continue to use halothane thereafter. However, this is a small study and this conclusion may not be valid generally. Methodology Any study of liver function tests with values below those used for the diagnosis of severe liver damage must be based on a knowledge of the normal enzyme values and the events which may affect them. In a recent review Burke (5) came to the conclusion that, despite possible advantages of greater specificity of ornithyl carbamoyl transferase and gamma glutamyl transpepsidase over the aminotransferases and alkaline phosphatase respectively, there is insufficient experience of their use and interpretation, and he concludes that a few simple tests of established value should be preferred. At the near-normal concentrations of aminotransferases with which this and similar studies are concerned, the accuracy of estimation and reproducibility of results become important. In studying the aminotransferases and LDH the following factors may affect the results: food (Rheingold, 58), menstruation (Hagerman and Wellington, 5) and red cell lysis. Red cell lysis is most important because erythrocytes contain three to five times the s.g.p.t., times the s.g.o.t. and 0 times the LDH concentrations of serum (Karmen, Wroblewski and La Due, 55). The effect of exercise on serum enzyme concentrations and whether or not a diurnal variation exists, is a matter of argument between various authorities. Agents which induce enzymes, such as alcohol, may affect the results also. For these reasons, constant sampling conditions and a standardized technique venepuncture with early separation of the plasma from the red cells was considered essential, and was

5 LIVER FUNCTION TESTS AFTER ANAESTHESIA adhered to strictly in this study. The storage of samples awaiting analysis has been mentioned earlier. In the analysis of samples, automated techniques should ensure reproducibility of results and have the advantage of running a series of tests simultaneously. In the interpretation of results further difficulties occur. All methods of measuring enzymes measure activity and not the quantity present, and it is not known if these are synonymous as indicators of liver damage. The normal ranges from a laboratory may be considerably larger than the variations found in individuals in health. Which is the better index: the value of the increase, in units, or the proportionate increase? This paper has followed the example set by colleagues in Oxford and Southampton, employing the proportionate increase, but a two-fold increase within the normal range, as in patient no. (s.g.o.t.) and patient no. (s.g.p.t.), has doubtful significance. Aspartate aminotransferase is an enzyme of the organelle, whereas alanine aminotransferase is from the cytoplasm. Thus differing alterations of the two may indicate a differing type or degree of injury. Lactate dehydrogenase, especially the slower moving iso-enzymes LD4 and LD5 may be helpful, but are not simple tests; the total LDH is more variable than the aminotransferases, since it occurs more widely in the body. The mechanism of liver damage following operation and anaesthesia remains a matter of dispute. With regard to halothane, it is perhaps of interest that anaesthetic concentrations of the agent inhibit the metabolism of sub-anaesthetic concentrations of the drug (Atallah and Geddes, 3), suggesting that modification of its metabolism is self-induced. It has been suggested also that halothane alters the immune status of the patient so allowing breakthrough by a virus already present. Neither of these theories can explain the apparent change in response to repeated administrations in the first to fourth anaesthetics as has been found in the Oxford and Southampton studies, and subsequently suggested by this study. ACKNOWLEDGEMENTS I wish to thank Col. I. Lister, F.R.C.S., under whose care the patients were admitted; Mr David Snell, B.SC., biochemist, and the other members of the laboratory staff Q.A.M.H. I wish also to thank the Director General, Army Medical Services, for permission to publish. REFERENCES Atallah, M. M., and Geddes, I. C. (3). Metabolism of halothane. Br. J. Anaesth., 45, 44. Burke, M. D. (5). Liver function. Hum. Pathol.,, 3. Burns, T. H. S., Mushin, W. W., Organe, G. S. W., and Robertson, J. D. (5). Clinical investigations of fluothane. Br. Med. J.,, 3. Hagerman, D., and Wellington, F. M. (5). Serum lactate dehydrogenase activity during pregnancy and in the newborn. Am. J. Obstet. Gynecol.,, 8. Jendrassik, L., and Grof, P. (). Vereinfacthe photometrische Methoden zur Bestimmung des Blutbilirubins. Biochem.Z.,, 81. Karmen, A., Wroblewski, F., and La Due, J. S. (55). Transaminase activity in human blood. J. Clin. Invest.,,. Mansell-Jones, D. (4). CSM/S/1, January 3. Morgenstern, S., Kessler, G., Auerbach, J., Flor, R. V., and Klein, B. (5). An automated serum alkaline phosphatase procedure for the autoanalyser. Clin. Chem.,, 8. Moult, P. J. A., and Sherlock, S. (5). Halothane related hepatitis. Q.J. Med., 44,. National Halothane Study, NAS NRC Report (). J.A.M.A.,, 5. Rheingold, J. G. (58). In Liver Function (ed. R. W. Bower), p.. Washington D.C: Am. Inst. Biol. Sci. Rush, R. L., Leon, L., and Kessler, G. (0). Response of the SMA--0 and autoanalyzer II inverse, colorimetry and 3 nm photometry. Clin. Chem.,, 5. Simpson, B. R., Strunin, L., and Walton, B. (5). Halothane and jaundice. Br. J. Hosp. Med.,, 4. Trowell, J., Petro, R., and Crampton-Smith, A. (5). Controlled trial of repeated halothane anaesthetics with carcinoma of uterine cervix treated with radium. Lancet, 1, 8. Virtue, R. W. (5). Halothane hepatitis. Survey of Anaesth.,,. Wright, R., Chisholm, M., Lloyd, B., Edwards, J. C, Eade, O. E., Hawksley, M., Moles, T. M., and Gardner, M. J. (5). Controlled prospective study of the effect on liver function of multiple exposures to halothane. Lancet TESTS 1, 8. DE LA FONCTION HEPATIQUE APRES ADMINISTRATION DE PRODUITS ANESTHESIQUES RESUME Des examens des fonctions hepatiques ont ete effectues sur 41 patients soumis a des anesthesies repetees aux fins de chirurgie sur les organes genito-urinaires et qui avaient recu dans le passe de multiples anesthesies par l'halothane, tout d'abord apres une anesthesie par l'halothane et ensuite apres une anesthesie sans halothane. On a constate une frequence de troubles hepatiques moins forte apres l'halothane qu'apres les produits anesthesiques ne contenant pas d'halothane. II n'y a eu aucune relation evidente entre le nombre des produits anesthesiques ou la duree totale de l'anesthesie et les troubles des examens des fonctions hepatiques.

6 0 BRITISH JOURNAL OF ANAESTHESIA LEBERFUNKTIONS-TESTS NACH VERABREICHUNG VON NARKOSEMITTEL ZUSAMMENFASSUNG Leberfunktionstests wurden an 41 Patienten vorgenommen, die fiir Operationen im genital-harntrakt mehrfachen Narkosen unterzogen waren, und die in der Vergangenheit multiple Halothan-Narkosemitte erhalten hatten, zuerst nach einer Halothannarkose und dann nach einer Narkose ohne Halo than. Nach Halothan kam es zu einer geringeren Haufigkeit von Leberfunktionsstdrungen als nach nichthalothanhaltigen Mitteln. Zwischen den Leberfunktionsstorungen und der Zahl der Narkosemittel oder der gesamten Narkosedauer gab es keine offensichtlichen Beziehungen. PRUEBAS DE LA FUNCION HEPATICA TRAS LA ANESTESIA SUMARIO Se realizaron pruebas funcionales hepaticas a 41 pacientes que requirieron frecuente anestesia en intervenciones genitourinarias (y que habian recibido en el pasado multiple anestesia con halotano), primero tras anestesia usando halotano, y luego tras un anestesico sin halotano. Hubo una frecuencia menor en el porcentaje de trastornos funcionales hepaticos tras el halotano que tras el anestesico sin halotano. No hubo una relacin evidente entre el niimero de anestesicos, ni la duration total de la anestesia, y la perturbation de las pruebas funcionales hepaticas.