Clinica Chin&a Acta, 202 (1991) 73-82 r%,1991 Elsevier Science Publishers B.V. All rights reserved 0~9-8981/91/$03.50
73
CCA 05073
Serum F-protein concentration following halothane or isoflurane anaesthesia CM. Cooper
I, G.R. Foster ‘, A.E. Cooper and D.B. Olivera ’
I, M. Kenny
’
’ Deparrmenf of Anaesthetics, Medical School, Royal Hallamshire Hospital, Sheffield, ’ Medical CJnit, St. Mary'sHospital, London and -’ Depurtmenr of Medicine, Addenbrooks Hospital, Cambridge (UK) (Received 8 October 1990; revision received 25 June 1991; accepted 5 July 1991) Key words: Anaesthesia; F-protein; Hepatitis; Liver; Halothane; Isoflurane
Summary We have investigated the prevalence of hepatic injury following uncomplicated anaesthesia using a sensitive and specific marker of hepatic damage, the serum F-protein concentration. The median variation in serum F-protein in fit adults over six days is 16 ng/ml, minimum 0 ng/ml, maximum 36 ng/ml. A significant rise in serum F-protein was demonstrated six days following anaesthesia and surgery, but not earlier after 3 or 24 h. There was no significant difference between patients who received halothane (n = 12) or isoflurane (n = 13). These changes were not related to duration of anaesthesia, quantity of delivered volatile agent or mode of ventilation. Hepatocellular damage may occur following anaesthesia for minor surgery.
Introduction Fulminant hepatitis is a rare complication of halothane anaesthesia [1,2]. It is associated with repeated exposure and is observed days rather than hours following inhalation of the drug [3]. Animal studies and recent studies in humans have indicated that subclinical halothane hepatotoxicity may be a common anaesthetic complication 14-71. The aetiology and incidence of halothane-related post-
Correspondence to: CM. Cooper, Department of Anaesthetics, Hospital, Glossup Road, Sheffield SIO ZRX, UK.
Medical School, Royat Hallamshire
74
anaesthetic hepatic damage is still a matter for debate [1,3]. Suggested mechanisms include biotransformation to toxic metabolites and hypersensitivity [8,9]. Halothane, enflurane and isoflurane are all useful anaesthetic agents and their respective influence on hepatic integrity requires further investigation [5,6]. Conventional tests of hepatic damage are either insensitive and non-specific (e.g., serum transaminases) or inducable by drugs (e.g., gamma glutamyl transferase - GGT) [lo]. F-protein is a 44 kDa hepatocyte cytoplasmic protein only found in minute quantities elsewhere in the body [ 111. Following the development of a reliable radioimmunoassay, Foster et al. have reported that the serum F-protein (SFP) concentration is a sensitive and specific marker of hepatocyte damage, which does not appear to be altered by known hepatic enzyme inducing drugs [ 121. Preliminary work has suggested that SFP may be a useful marker of post-operative hepatocyte damage [7]. This work has been extended. Two studies are reported. These were designed to establish the normal variation in SFP with time and the pattern of alteration in SFP following inhalational anaesthesia for minor elective surgery.
Methods
Local ethical committee approval was obtained and all subjects gave informed consent. The study was conducted in two parts. Study 1 was designed to establish the normal variation in SFP with time. Study 2 was designed to investigate the change in SFP following surgery conducted under inhalational anaesthesia.
Study 1
Fifteen healthy volunteer male individuals were studied. Ages ranged from 19 to 29, mean 20. Blood samples were taken in the morning with the subjects fasting on day 0 and again on day 6. None of the subjects had a history of previous liver disease or other significant illness, were not on medication, drank less than 20 units of alcohol per week and had not had genera1 anaesthesia within six months. Exclusion criteria included abnormal liver function tests (LFTs; detailed below), obesity, recent blood transfusion and recent illness. The blood samples were analyzed for SFP, urea and electrolytes (U + E), full blood count (FBC) and the following LFTs: aspartate transaminase (AST, enzyme commission number: 2.6.1.11, GGT (enzyme commission number: 2.3.2.2), alkaline phosphatase (ALP, enzyme commission number: 3.1.3.1) and bilirubin. LFTs and U + E were measured with a Technicon SMAC-2 (Bayer Technicon, Basingstoke, U.K.). FBC was measured with a Technicon H6000 analyser (Bayer Technicon, Basingstoke). SFP was measured as previously described [12]. U + E, LFTs and FBC were all within the normal range.
Twenty-six patients gave consent to be included in the trial. One patient was excluded from the trial having subsequently withdrawn consent. All patients were without significant systemic disease and were scheduled for minor elective surgery. There was no statistical difference in demographic data between the two groups (Table I). All were non-smokers, gave no history of previous liver or other significant disease, were not on medication known to alter. liver function, drank less than 15 units of alcohol per week, had not had general anaesthesia within six months and were not pregnant. Exclusion criteria included raised pre-operative LFTs, obesity, recent or per-operative blood transfusion, blood loss in excess of 10% circulating blood volume during the study and any peri-operative event (other than surgery and anaesthesia) known to be associated with marked alteration of liver blood flow, for example, significant hypotension. Initial U + E, FBC and pre-operative LFTs were within normal limits. Blood pressure, pulse, temperature, fluid balance and respiration were unremarkable throughout the study. There was no unplanned additional medication given to any patient during the study period. None of the patients required additional incidental investigation. Patients were randomly allocated to receive one of two volatile anaesthetic agents, either halothane or isoflurane. All patients were fasted and premeditated with oral temazepam 20 mg one hour prior to anaesthesia which was induced with thiopentone 4-6 mg/kg. Anaesthesia was maintained with 66% nitrous oxide and the volatile agent in oxygen. According to the requirements of their surgery, patients were either intubated and given intermittent positive pressure ventilation (IPPV) via a nonrebreathing circuit or spontaneously ventilated (SV) through a semi-closed anaesthetic circuit utilising generous gas flows (soda lime was not used). If intubated and ventilated, minute ventilation was 100 ml/kg. Maintenance relaxation was reversed with neostigmine 2.5 mg in atropine 1.2 mg at the end of the procedure. The concentration of volatile anaesthetic agent was varied according to normal clinical practice. Morphine was given during the procedure to a total
TABLE
I
Demographic
data and details
Age (yr) Height (cm) Weight (kg) Sex (male) Duration of anaesthesia Time-weighted volatile average (min%,)
* SD
(min) agent
of anaesthesia
for Study 2 (mean values)
*
Group A (n = 12)
Group B (n = 13)
39 166 67 5 50
3x 170 69 5 43
(17) (h) (12) (23)
32 (20)
(20) (7) (12) (22)
45 (40)
of 0.05 mg/kg and, during the post-operative period, to a total of 0.14 mg/kg in any 4 h, as required. Total delivery of volatile anaesthetic agent was measured in terms of the concentration of volatile anaesthetic agent administered to the patient and the duration over which the agent was given. This was expressed as the time-weighted volatile agent average (duration of anaesthesia x % delivered anaesthetic concentration, expressed as min %o>[6]. Blood samples were taken initially before and subsequently after 3 and 24 h following anaesthesia. Those patients within easy reach of the hospital were interviewed at home six days following surgery and a further blood sample taken. These samples were analysed as described in the Study 1 Methods section for SFP, U + E, FBC, and LFTs. LFTs, U + E and FBC remained within the normal range throughout the study period. Routine intra-operative and post-operative monitoring was recorded in addition to post-operative analgesia, medication, surgical progress and incidental laboratory investigations. Statistical analysis Demographic data were examined using normal theory. Data from Study 1 and Study 2 were analysed separately by means of the Friedman 2-way Anova analysis. The frequency of abnormal results in the different groups was analysed using Chi-square. The patients in Study 2 acted as their own controls when analysing alteration in SFP due to anaesthesia and surgery. Results Study 1 There was no significant change in SFP during the six-day study period. Median SFP for the group was 43 ng/ml, minimum 2 ng/ml, maximum 105 ng/ml, lower quartile 25 ng/ml and upper quartile 55 ng/ml. The median change in SFP during the six-day study period was 16 ng/ml, minimum 0 ng/ml, maximum 36 ng/ml, lower quartile 7 ng/ml and upper quartile 24 ng/ml. Study 2 Twenty-five patients were randomly allocated as follows: the halothane group contained 12 patients, the isoflurane group 13. There was no significant difference in duration of anaesthesia (Table I), or numbers ventilated between the groups. Administrative difficulties prevented 4% of samples being analysed. Figs. 1, 2a and 2b show the effect of anaesthesia and surgery on the SFP concentration. There was no significant alteration in SFP during the first 24 h post-operatively in either group, or when both groups were combined. However, one patient, who received IPPV with halothane, had developed, by 24 h post-anaesthesia, a rise in SFP of greater than 140% of the maximum change observed in Study 1 (i.e. > 50 ng/ml). SFP rose from 20 ng/ml to 78 ng/ml. This change persisted at six days post-anaesthesia (patient D, Table IIa).
Sixteen patients were studied at six days, 10 in the halothane group and 6 in the isoflurane group (Figs. 1, 2a, 2b). There was a significant increase in the SFP concentration when compared to pre-anaesthetic values when both groups were combined (P < 0.05). There was no significant difference between the groups. However, there was evidence of a trend towards more marked rises in SFP concentration in the halothane group than the isoflurane group at six days (Figs. 2a, 2b).
HALOTHANE
GROUP
CA
ISOFLU~ANE
‘00-I
GROUP
2‘b HOURS
Fig. 1. Serum
F-protein
levels at 3 h, 24 h and 6 days following values.
anaesthesia
relative
to preoperative
7x
1
Study
Study 2
a 0
m
0
I
q
__+&__g__-j
--ca--
4
0 0
3 hours
6 days
Time After First Sample
24 hours
Time
6 day
Post Anaesthetic
Study 1
Study 2
I
e
0
0 0
0
8 % I
3 hours
6 days
After First Sample
Time Fig. 2. a. Change
in serum F-protein
halothane
anaesthesia.
F-protein
level
from
Postoperative preoperative Postoperative
TABLE
6 days
Time Post Anaesthetic
level from preoperative value subtracted
value
-I-
24 hours
3 h, 24 h and
value subtracted
value 3 h, 24 h and 6 days following
from preoperative
value.
h days following
from preoperative
in serum
anaesthesia.
value.
Ila
Halothane
“. Anaesthetic
details of those patients in whom. by day six. serum F-protein
than 140% of the maximum
change observed in Study
Patient
of
Duration
1 (i.e.
Time-weighted
Mode of
Change in serum
anaesthesia
volatile agent
ventilation
F-protein
(min)
average
(mint%,)
43
22
IPPV
X6
B
35
18
IPPV
62
C
35
IX
IPPV
62
D
57
40
IPPV
52
mean
(SD)
h Post-operative
rose by greater
> 50 ng/ml)
A
Group
b. Change
isotlurane
53
32
(23)
(20)
value subtracted
from pre-operative
value
(ng/ml)
h
79
TABLE Isoflurane
IIb ‘. Anaesthetic
details of those patients in whom, by day six, serum F-protein
than 140% of the maximum Patient
Time-weighted
Mode of
Change in serum
anaesthesia
volatile agent
ventilation
F-protein
(mini
average (min%I SV
57
IPPV
52
Duration
of
E
38
135
F
30
15
Group mean
43
45
(221
(40)
(SD)
rose by greater
change observed in Study 1 (i.e. > 50 ng/mll
tng/mll
h
a n=6. ’ Post-operative
value subtracted
from pre-operative
value
In the halothane group at six days, the SFP was markedly changed from the pre-anaesthetic level in 4 patients (a rise in SFP of greater than 140% of the maximum change observed in Study 1, i.e. > 50 ng/ml), Table IIa. All four received IPPV. The SFP measured for patient A increased from 39 ng/ml pre-operatively to 125 ng/ml at six days. This patient received 0.5% halothane for 43 min, less than both the mean duration of anaesthesia and the mean timeweighted volatile agent average for the halothane group (Table I). Of the other 3 patients in the halothane group showing a similar rise in SFP concentration, both the durations of patients B and C’s anaesthesia and their time-weighted volatile agent average deliveries were less than the corresponding means for the halothane group as a whole (Table I>. Patient D had a longer duration of anaesthesia and a greater time-weighted volatile agent average delivery of halothane than the halothane group mean, but not the greatest rise in SFP concentration. Two patients in the isoflurane group showed a rise in SFP of greater than 140% of the maximum change observed in Study 1 at six days (Table IIb). Both patients were anaesthetised for less than the mean duration of anaesthesia in the isoflurane group. However, patient E, who breathed spontaneously, received more than the isoflurane group mean time-weighted volatile agent average delivery of isoflurane, while patient F, who was ventilated by IPPV, received less than the group mean time-weighted volatile agent average delivery of isoflurane (Table IIb). There were no significant changes measured in LFTs during the study period. Despite the random allocation of patients to each group, the difference in mean delivery of anaesthetic agent between each group is not fully accounted for by the higher MAC of isoflurane (Table I>. Two patients in the isoflurane group received a greater delivery of volatile agent not matched by patients in the halothane group. The first patient received a delivery of 115 min % isoflurane over 95 min by IPPV, associated with unremarkable alterations in SFP. The second, patient E (Table IIb), received 135 min % isoflurane over 45 min by SV. This anaesthetic was associated with a notable rise in SFP concentration. There was no significant relationship between mode of ventilation and SFP.
Discussion
Study 1 has established that the median day to day variability of SFP is 16 ng/ml, the minimum and maximum observed changes being 0 and 36 ng/ml, respectively. Study 2 has established that anaesthesia and surgery are together associated with a significant rise in SFP on the sixth post-operative day, confirming a previous report [7]. However, this result is not due to a generalised rise in SFP; a rise was not demonstrated in all patients. Four of ten patients given halothane and two of six patients given isoflurane in Study 2 developed a rise in SFP of greater than 140% of the maximum change observed in Study 1. It is this data that has established a statistically significant rise in SFP for the study group as a whole at six days following anaesthesia and surgery. The difference at six days between the isoflurane group and the halothane group was not statistically significant, but this may be due to the relatively small number of patients studied. There was no correlation between changes in SFP and exposure to anaesthetic as judged by duration of anaesthesia or time-weighted volatile agent average. Nor was there a relationship between mode of ventilation and alteration in SFP; however, a larger study group in which end-tidal carbon dioxide partial pressure and end-tidal volatile agent partial pressure are recorded is being planned to establish a clearer understanding of these relationships. The median SFP in both the patients and the control subjects was slightly higher than previously reported [7]. The assay used in the present study was similar to that previously described [12], but was performed at a different location using a different beta particle counter. These slight differences in assay conditions probably account for the discrepancy in the median SFP in healthy patients. All samples in the current study were assayed in triplicate at the same time and the observed changes cannot be ascribed to variations in the assay. Conventional LFTs remained within the normal range throughout the study. However, these tests are relatively insensitive and the absence of any change does not exclude hepatic injury [13]. SFP is a sensitive and specific measure of hepatocyte damage which shows a close correlation with histopathological evidence of hepatocyte damage caused by a wide variety of disease and drugs [12]. Of particular significance, is that SFP does not rise following drug induced liver enzyme induction (Foster GR., K M. and Olivera DBG., in preparation). F-protein is not found in significant quantities in other tissues [ 111 and SFP is not increased by non-hepatic disease [12], suggesting that surgical trauma is unlikely to account for the observed changes. Hussey and colleagues have recently reported plasma GST levels are a sensitive indicator of hepatic damage during halothane and enflurane anaesthesia [5]. They demonstrated a biphasic pattern of post-operative alteration in plasma GST which is most pronounced following halothane. There is an early rise in plasma GST at three hours in the majority of patients receiving halothane and a secondary rise at 24 h. This data is in contrast to that presented here. These early changes in plasma GST are not reflected in rises in SFP, apart from one patient in whom the SFP
81
rose from 20 ng/mI pre-operatively to 78 ng/ml at 24 h and dropped slightly to 72 ng/ml at six days. No explanation is offered for this isolated result. The significance of these early changes in GST and their relationship to the later changes in SFP is not clear. Hussey has not reported measuring plasma GST concentration more than 24 h following anaesthesia. GST and SFP have been directly compared in paracetomol poisoning (Plasma glutathione S-transferase and F-protein measurements are more sensitive markers of paracetomol-induced liver damage than alanine aminotransferase (Beckett GJ, Foster GR, Hussey AJ, Olivera DBG, Donovan JW, Prescott LF and Proudfoot AT: Clin Chem, in press). Under these circumstances, changes in both proteins show a similar time course, suggesting that the temporal difference in the serum concentration of the two markers following anaesthesia and surgery is not due to a difference in their release or plasma half-lives. GST occurs predominantIy in centrilobular hepatocytes [14], whereas F-protein is more uniformly distributed. It is likely that plasma GST is a more sensitive marker of hypoxic hepatic injury, since the centrilobular hepatocytes are most susceptible to this insult. It is possible that early post-operative liver damage (within 24 h) is related either directly or indirectly to per-operative hepatic hypoxia via the formation of hypoxia-induced metabolites. The aetiology of the late hepatic injury we have observed with SFP is not clear, possible mechanisms include hypersensitivity reactions or delayed drug toxicity, as is seen with paracetomol. This study has demonstrated that SFP rises significantly at six days following anaesthesia and surgery. This rise, which occurs frequently following anaesthesia including halothane or isoflurane, represents hepatocellular damage and does not appear to be dose related. The mechanism of this injury and the relationship to previous reports of early hepatic damage following anaesthesia is not yet clear. Further studies are required to determine the aetiology and clinical significance of this late onset post-anaesthetic hepatocellular injury.
References 1 2 3 4 5
6 7 8
Spence AA, (Editorial). Halothane in the doldrums. Br J Anaes 1897;59:529-530. Brown BR, Gandolfi AJ. Adverse effects of volatile anaesthetics. Br J Anaes. 1987;59:14-23. Editorial. Halothane associated liver damage. Lancet 1986;1251-1252. McLain GE, Sipes IG, Brown BR. An animal model of halothane hepatotoxicity: roles of enzyme induction and hypoxia. Anaesthesiology 1979;51:321-326. Hussey AJ, Aldridge LM, Paul D, Ray DC, Beckett GJ, Allan LG. Plasma glutathione S-transferase concentration as a measure of hepatocellular integrity following a single general anaesthetic with halothane enflurane or isoflurane. Br J Anaes 1988;60:130-135. Ray DC, Howie AF, Beckett GJ, Drummond GB. Preoperative cimetidine does not prevent subclinical halothane hepatotoxicity in man. Br J Anaes 1989;63:531-535. Foster GR, Bowness P, Holder K and Olivera DBG. Hepatotoxicity after general anaesthesia. Br J Anaes 1988;61:120. Cousins MJ, Gourlay GK, Knights KM, Hall P de la M, Lunam CA. O’Brian P. A randomised prospective controlled study of the metabolism and hepatotoxicity of haiothane in humans. Anaesthesia Analgesia 198~66:299-308.
x2 Y Vergani D, Mieli-Vergani G, Alberti A, Neubergor J, Eddleston AL, Davis M, Williams R. Antibodies to the surface of halothane altered rabbit hepatocytes in patients with severe halothane associated hepatitis. N Engl J Med. lY80:303:66-71. 10 Allan LG. Hussey AJ. Howie J. Beckett GJ. Smith AF. Hayes JD. Drummonnd GB. Hepatic glutathione S-transferase release afterhalothane anaesthesia: open randomised comparison with isoflurane. Lancet lY87;1:771-773. 11 Griffiths JA and Olivera DBG. The organ distribution of F-protein in the mouse. Stand J Immunol. lY88;27:357-360. 12 Foster CR, Goldin RD and Olivera DBG. Serum F-protein: a new sensitive and specific test of hepatocellular damage. Clin Chim Acta 1989;184:85-92. 13 Wo A, Slavin G, Levi AJ. Elevated serum gamma-glutamyl transferase and histological liver damage in alcoholism. Am J Gastroenterol 1976;65:318-323. I4 Redick JA. Jackoby and Baron J. Immunohistochemical localisation of glutathione S-transferase in livers of untreated rats. J Biol Chem. 1982;257:15200-15203.
73
CCA 05073
Serum F-protein concentration following halothane or isoflurane anaesthesia CM. Cooper
I, G.R. Foster ‘, A.E. Cooper and D.B. Olivera ’
I, M. Kenny
’
’ Deparrmenf of Anaesthetics, Medical School, Royal Hallamshire Hospital, Sheffield, ’ Medical CJnit, St. Mary'sHospital, London and -’ Depurtmenr of Medicine, Addenbrooks Hospital, Cambridge (UK) (Received 8 October 1990; revision received 25 June 1991; accepted 5 July 1991) Key words: Anaesthesia; F-protein; Hepatitis; Liver; Halothane; Isoflurane
Summary We have investigated the prevalence of hepatic injury following uncomplicated anaesthesia using a sensitive and specific marker of hepatic damage, the serum F-protein concentration. The median variation in serum F-protein in fit adults over six days is 16 ng/ml, minimum 0 ng/ml, maximum 36 ng/ml. A significant rise in serum F-protein was demonstrated six days following anaesthesia and surgery, but not earlier after 3 or 24 h. There was no significant difference between patients who received halothane (n = 12) or isoflurane (n = 13). These changes were not related to duration of anaesthesia, quantity of delivered volatile agent or mode of ventilation. Hepatocellular damage may occur following anaesthesia for minor surgery.
Introduction Fulminant hepatitis is a rare complication of halothane anaesthesia [1,2]. It is associated with repeated exposure and is observed days rather than hours following inhalation of the drug [3]. Animal studies and recent studies in humans have indicated that subclinical halothane hepatotoxicity may be a common anaesthetic complication 14-71. The aetiology and incidence of halothane-related post-
Correspondence to: CM. Cooper, Department of Anaesthetics, Hospital, Glossup Road, Sheffield SIO ZRX, UK.
Medical School, Royat Hallamshire
74
anaesthetic hepatic damage is still a matter for debate [1,3]. Suggested mechanisms include biotransformation to toxic metabolites and hypersensitivity [8,9]. Halothane, enflurane and isoflurane are all useful anaesthetic agents and their respective influence on hepatic integrity requires further investigation [5,6]. Conventional tests of hepatic damage are either insensitive and non-specific (e.g., serum transaminases) or inducable by drugs (e.g., gamma glutamyl transferase - GGT) [lo]. F-protein is a 44 kDa hepatocyte cytoplasmic protein only found in minute quantities elsewhere in the body [ 111. Following the development of a reliable radioimmunoassay, Foster et al. have reported that the serum F-protein (SFP) concentration is a sensitive and specific marker of hepatocyte damage, which does not appear to be altered by known hepatic enzyme inducing drugs [ 121. Preliminary work has suggested that SFP may be a useful marker of post-operative hepatocyte damage [7]. This work has been extended. Two studies are reported. These were designed to establish the normal variation in SFP with time and the pattern of alteration in SFP following inhalational anaesthesia for minor elective surgery.
Methods
Local ethical committee approval was obtained and all subjects gave informed consent. The study was conducted in two parts. Study 1 was designed to establish the normal variation in SFP with time. Study 2 was designed to investigate the change in SFP following surgery conducted under inhalational anaesthesia.
Study 1
Fifteen healthy volunteer male individuals were studied. Ages ranged from 19 to 29, mean 20. Blood samples were taken in the morning with the subjects fasting on day 0 and again on day 6. None of the subjects had a history of previous liver disease or other significant illness, were not on medication, drank less than 20 units of alcohol per week and had not had genera1 anaesthesia within six months. Exclusion criteria included abnormal liver function tests (LFTs; detailed below), obesity, recent blood transfusion and recent illness. The blood samples were analyzed for SFP, urea and electrolytes (U + E), full blood count (FBC) and the following LFTs: aspartate transaminase (AST, enzyme commission number: 2.6.1.11, GGT (enzyme commission number: 2.3.2.2), alkaline phosphatase (ALP, enzyme commission number: 3.1.3.1) and bilirubin. LFTs and U + E were measured with a Technicon SMAC-2 (Bayer Technicon, Basingstoke, U.K.). FBC was measured with a Technicon H6000 analyser (Bayer Technicon, Basingstoke). SFP was measured as previously described [12]. U + E, LFTs and FBC were all within the normal range.
Twenty-six patients gave consent to be included in the trial. One patient was excluded from the trial having subsequently withdrawn consent. All patients were without significant systemic disease and were scheduled for minor elective surgery. There was no statistical difference in demographic data between the two groups (Table I). All were non-smokers, gave no history of previous liver or other significant disease, were not on medication known to alter. liver function, drank less than 15 units of alcohol per week, had not had general anaesthesia within six months and were not pregnant. Exclusion criteria included raised pre-operative LFTs, obesity, recent or per-operative blood transfusion, blood loss in excess of 10% circulating blood volume during the study and any peri-operative event (other than surgery and anaesthesia) known to be associated with marked alteration of liver blood flow, for example, significant hypotension. Initial U + E, FBC and pre-operative LFTs were within normal limits. Blood pressure, pulse, temperature, fluid balance and respiration were unremarkable throughout the study. There was no unplanned additional medication given to any patient during the study period. None of the patients required additional incidental investigation. Patients were randomly allocated to receive one of two volatile anaesthetic agents, either halothane or isoflurane. All patients were fasted and premeditated with oral temazepam 20 mg one hour prior to anaesthesia which was induced with thiopentone 4-6 mg/kg. Anaesthesia was maintained with 66% nitrous oxide and the volatile agent in oxygen. According to the requirements of their surgery, patients were either intubated and given intermittent positive pressure ventilation (IPPV) via a nonrebreathing circuit or spontaneously ventilated (SV) through a semi-closed anaesthetic circuit utilising generous gas flows (soda lime was not used). If intubated and ventilated, minute ventilation was 100 ml/kg. Maintenance relaxation was reversed with neostigmine 2.5 mg in atropine 1.2 mg at the end of the procedure. The concentration of volatile anaesthetic agent was varied according to normal clinical practice. Morphine was given during the procedure to a total
TABLE
I
Demographic
data and details
Age (yr) Height (cm) Weight (kg) Sex (male) Duration of anaesthesia Time-weighted volatile average (min%,)
* SD
(min) agent
of anaesthesia
for Study 2 (mean values)
*
Group A (n = 12)
Group B (n = 13)
39 166 67 5 50
3x 170 69 5 43
(17) (h) (12) (23)
32 (20)
(20) (7) (12) (22)
45 (40)
of 0.05 mg/kg and, during the post-operative period, to a total of 0.14 mg/kg in any 4 h, as required. Total delivery of volatile anaesthetic agent was measured in terms of the concentration of volatile anaesthetic agent administered to the patient and the duration over which the agent was given. This was expressed as the time-weighted volatile agent average (duration of anaesthesia x % delivered anaesthetic concentration, expressed as min %o>[6]. Blood samples were taken initially before and subsequently after 3 and 24 h following anaesthesia. Those patients within easy reach of the hospital were interviewed at home six days following surgery and a further blood sample taken. These samples were analysed as described in the Study 1 Methods section for SFP, U + E, FBC, and LFTs. LFTs, U + E and FBC remained within the normal range throughout the study period. Routine intra-operative and post-operative monitoring was recorded in addition to post-operative analgesia, medication, surgical progress and incidental laboratory investigations. Statistical analysis Demographic data were examined using normal theory. Data from Study 1 and Study 2 were analysed separately by means of the Friedman 2-way Anova analysis. The frequency of abnormal results in the different groups was analysed using Chi-square. The patients in Study 2 acted as their own controls when analysing alteration in SFP due to anaesthesia and surgery. Results Study 1 There was no significant change in SFP during the six-day study period. Median SFP for the group was 43 ng/ml, minimum 2 ng/ml, maximum 105 ng/ml, lower quartile 25 ng/ml and upper quartile 55 ng/ml. The median change in SFP during the six-day study period was 16 ng/ml, minimum 0 ng/ml, maximum 36 ng/ml, lower quartile 7 ng/ml and upper quartile 24 ng/ml. Study 2 Twenty-five patients were randomly allocated as follows: the halothane group contained 12 patients, the isoflurane group 13. There was no significant difference in duration of anaesthesia (Table I), or numbers ventilated between the groups. Administrative difficulties prevented 4% of samples being analysed. Figs. 1, 2a and 2b show the effect of anaesthesia and surgery on the SFP concentration. There was no significant alteration in SFP during the first 24 h post-operatively in either group, or when both groups were combined. However, one patient, who received IPPV with halothane, had developed, by 24 h post-anaesthesia, a rise in SFP of greater than 140% of the maximum change observed in Study 1 (i.e. > 50 ng/ml). SFP rose from 20 ng/ml to 78 ng/ml. This change persisted at six days post-anaesthesia (patient D, Table IIa).
Sixteen patients were studied at six days, 10 in the halothane group and 6 in the isoflurane group (Figs. 1, 2a, 2b). There was a significant increase in the SFP concentration when compared to pre-anaesthetic values when both groups were combined (P < 0.05). There was no significant difference between the groups. However, there was evidence of a trend towards more marked rises in SFP concentration in the halothane group than the isoflurane group at six days (Figs. 2a, 2b).
HALOTHANE
GROUP
CA
ISOFLU~ANE
‘00-I
GROUP
2‘b HOURS
Fig. 1. Serum
F-protein
levels at 3 h, 24 h and 6 days following values.
anaesthesia
relative
to preoperative
7x
1
Study
Study 2
a 0
m
0
I
q
__+&__g__-j
--ca--
4
0 0
3 hours
6 days
Time After First Sample
24 hours
Time
6 day
Post Anaesthetic
Study 1
Study 2
I
e
0
0 0
0
8 % I
3 hours
6 days
After First Sample
Time Fig. 2. a. Change
in serum F-protein
halothane
anaesthesia.
F-protein
level
from
Postoperative preoperative Postoperative
TABLE
6 days
Time Post Anaesthetic
level from preoperative value subtracted
value
-I-
24 hours
3 h, 24 h and
value subtracted
value 3 h, 24 h and 6 days following
from preoperative
value.
h days following
from preoperative
in serum
anaesthesia.
value.
Ila
Halothane
“. Anaesthetic
details of those patients in whom. by day six. serum F-protein
than 140% of the maximum
change observed in Study
Patient
of
Duration
1 (i.e.
Time-weighted
Mode of
Change in serum
anaesthesia
volatile agent
ventilation
F-protein
(min)
average
(mint%,)
43
22
IPPV
X6
B
35
18
IPPV
62
C
35
IX
IPPV
62
D
57
40
IPPV
52
mean
(SD)
h Post-operative
rose by greater
> 50 ng/ml)
A
Group
b. Change
isotlurane
53
32
(23)
(20)
value subtracted
from pre-operative
value
(ng/ml)
h
79
TABLE Isoflurane
IIb ‘. Anaesthetic
details of those patients in whom, by day six, serum F-protein
than 140% of the maximum Patient
Time-weighted
Mode of
Change in serum
anaesthesia
volatile agent
ventilation
F-protein
(mini
average (min%I SV
57
IPPV
52
Duration
of
E
38
135
F
30
15
Group mean
43
45
(221
(40)
(SD)
rose by greater
change observed in Study 1 (i.e. > 50 ng/mll
tng/mll
h
a n=6. ’ Post-operative
value subtracted
from pre-operative
value
In the halothane group at six days, the SFP was markedly changed from the pre-anaesthetic level in 4 patients (a rise in SFP of greater than 140% of the maximum change observed in Study 1, i.e. > 50 ng/ml), Table IIa. All four received IPPV. The SFP measured for patient A increased from 39 ng/ml pre-operatively to 125 ng/ml at six days. This patient received 0.5% halothane for 43 min, less than both the mean duration of anaesthesia and the mean timeweighted volatile agent average for the halothane group (Table I). Of the other 3 patients in the halothane group showing a similar rise in SFP concentration, both the durations of patients B and C’s anaesthesia and their time-weighted volatile agent average deliveries were less than the corresponding means for the halothane group as a whole (Table I>. Patient D had a longer duration of anaesthesia and a greater time-weighted volatile agent average delivery of halothane than the halothane group mean, but not the greatest rise in SFP concentration. Two patients in the isoflurane group showed a rise in SFP of greater than 140% of the maximum change observed in Study 1 at six days (Table IIb). Both patients were anaesthetised for less than the mean duration of anaesthesia in the isoflurane group. However, patient E, who breathed spontaneously, received more than the isoflurane group mean time-weighted volatile agent average delivery of isoflurane, while patient F, who was ventilated by IPPV, received less than the group mean time-weighted volatile agent average delivery of isoflurane (Table IIb). There were no significant changes measured in LFTs during the study period. Despite the random allocation of patients to each group, the difference in mean delivery of anaesthetic agent between each group is not fully accounted for by the higher MAC of isoflurane (Table I>. Two patients in the isoflurane group received a greater delivery of volatile agent not matched by patients in the halothane group. The first patient received a delivery of 115 min % isoflurane over 95 min by IPPV, associated with unremarkable alterations in SFP. The second, patient E (Table IIb), received 135 min % isoflurane over 45 min by SV. This anaesthetic was associated with a notable rise in SFP concentration. There was no significant relationship between mode of ventilation and SFP.
Discussion
Study 1 has established that the median day to day variability of SFP is 16 ng/ml, the minimum and maximum observed changes being 0 and 36 ng/ml, respectively. Study 2 has established that anaesthesia and surgery are together associated with a significant rise in SFP on the sixth post-operative day, confirming a previous report [7]. However, this result is not due to a generalised rise in SFP; a rise was not demonstrated in all patients. Four of ten patients given halothane and two of six patients given isoflurane in Study 2 developed a rise in SFP of greater than 140% of the maximum change observed in Study 1. It is this data that has established a statistically significant rise in SFP for the study group as a whole at six days following anaesthesia and surgery. The difference at six days between the isoflurane group and the halothane group was not statistically significant, but this may be due to the relatively small number of patients studied. There was no correlation between changes in SFP and exposure to anaesthetic as judged by duration of anaesthesia or time-weighted volatile agent average. Nor was there a relationship between mode of ventilation and alteration in SFP; however, a larger study group in which end-tidal carbon dioxide partial pressure and end-tidal volatile agent partial pressure are recorded is being planned to establish a clearer understanding of these relationships. The median SFP in both the patients and the control subjects was slightly higher than previously reported [7]. The assay used in the present study was similar to that previously described [12], but was performed at a different location using a different beta particle counter. These slight differences in assay conditions probably account for the discrepancy in the median SFP in healthy patients. All samples in the current study were assayed in triplicate at the same time and the observed changes cannot be ascribed to variations in the assay. Conventional LFTs remained within the normal range throughout the study. However, these tests are relatively insensitive and the absence of any change does not exclude hepatic injury [13]. SFP is a sensitive and specific measure of hepatocyte damage which shows a close correlation with histopathological evidence of hepatocyte damage caused by a wide variety of disease and drugs [12]. Of particular significance, is that SFP does not rise following drug induced liver enzyme induction (Foster GR., K M. and Olivera DBG., in preparation). F-protein is not found in significant quantities in other tissues [ 111 and SFP is not increased by non-hepatic disease [12], suggesting that surgical trauma is unlikely to account for the observed changes. Hussey and colleagues have recently reported plasma GST levels are a sensitive indicator of hepatic damage during halothane and enflurane anaesthesia [5]. They demonstrated a biphasic pattern of post-operative alteration in plasma GST which is most pronounced following halothane. There is an early rise in plasma GST at three hours in the majority of patients receiving halothane and a secondary rise at 24 h. This data is in contrast to that presented here. These early changes in plasma GST are not reflected in rises in SFP, apart from one patient in whom the SFP
81
rose from 20 ng/mI pre-operatively to 78 ng/ml at 24 h and dropped slightly to 72 ng/ml at six days. No explanation is offered for this isolated result. The significance of these early changes in GST and their relationship to the later changes in SFP is not clear. Hussey has not reported measuring plasma GST concentration more than 24 h following anaesthesia. GST and SFP have been directly compared in paracetomol poisoning (Plasma glutathione S-transferase and F-protein measurements are more sensitive markers of paracetomol-induced liver damage than alanine aminotransferase (Beckett GJ, Foster GR, Hussey AJ, Olivera DBG, Donovan JW, Prescott LF and Proudfoot AT: Clin Chem, in press). Under these circumstances, changes in both proteins show a similar time course, suggesting that the temporal difference in the serum concentration of the two markers following anaesthesia and surgery is not due to a difference in their release or plasma half-lives. GST occurs predominantIy in centrilobular hepatocytes [14], whereas F-protein is more uniformly distributed. It is likely that plasma GST is a more sensitive marker of hypoxic hepatic injury, since the centrilobular hepatocytes are most susceptible to this insult. It is possible that early post-operative liver damage (within 24 h) is related either directly or indirectly to per-operative hepatic hypoxia via the formation of hypoxia-induced metabolites. The aetiology of the late hepatic injury we have observed with SFP is not clear, possible mechanisms include hypersensitivity reactions or delayed drug toxicity, as is seen with paracetomol. This study has demonstrated that SFP rises significantly at six days following anaesthesia and surgery. This rise, which occurs frequently following anaesthesia including halothane or isoflurane, represents hepatocellular damage and does not appear to be dose related. The mechanism of this injury and the relationship to previous reports of early hepatic damage following anaesthesia is not yet clear. Further studies are required to determine the aetiology and clinical significance of this late onset post-anaesthetic hepatocellular injury.
References 1 2 3 4 5
6 7 8
Spence AA, (Editorial). Halothane in the doldrums. Br J Anaes 1897;59:529-530. Brown BR, Gandolfi AJ. Adverse effects of volatile anaesthetics. Br J Anaes. 1987;59:14-23. Editorial. Halothane associated liver damage. Lancet 1986;1251-1252. McLain GE, Sipes IG, Brown BR. An animal model of halothane hepatotoxicity: roles of enzyme induction and hypoxia. Anaesthesiology 1979;51:321-326. Hussey AJ, Aldridge LM, Paul D, Ray DC, Beckett GJ, Allan LG. Plasma glutathione S-transferase concentration as a measure of hepatocellular integrity following a single general anaesthetic with halothane enflurane or isoflurane. Br J Anaes 1988;60:130-135. Ray DC, Howie AF, Beckett GJ, Drummond GB. Preoperative cimetidine does not prevent subclinical halothane hepatotoxicity in man. Br J Anaes 1989;63:531-535. Foster GR, Bowness P, Holder K and Olivera DBG. Hepatotoxicity after general anaesthesia. Br J Anaes 1988;61:120. Cousins MJ, Gourlay GK, Knights KM, Hall P de la M, Lunam CA. O’Brian P. A randomised prospective controlled study of the metabolism and hepatotoxicity of haiothane in humans. Anaesthesia Analgesia 198~66:299-308.
x2 Y Vergani D, Mieli-Vergani G, Alberti A, Neubergor J, Eddleston AL, Davis M, Williams R. Antibodies to the surface of halothane altered rabbit hepatocytes in patients with severe halothane associated hepatitis. N Engl J Med. lY80:303:66-71. 10 Allan LG. Hussey AJ. Howie J. Beckett GJ. Smith AF. Hayes JD. Drummonnd GB. Hepatic glutathione S-transferase release afterhalothane anaesthesia: open randomised comparison with isoflurane. Lancet lY87;1:771-773. 11 Griffiths JA and Olivera DBG. The organ distribution of F-protein in the mouse. Stand J Immunol. lY88;27:357-360. 12 Foster CR, Goldin RD and Olivera DBG. Serum F-protein: a new sensitive and specific test of hepatocellular damage. Clin Chim Acta 1989;184:85-92. 13 Wo A, Slavin G, Levi AJ. Elevated serum gamma-glutamyl transferase and histological liver damage in alcoholism. Am J Gastroenterol 1976;65:318-323. I4 Redick JA. Jackoby and Baron J. Immunohistochemical localisation of glutathione S-transferase in livers of untreated rats. J Biol Chem. 1982;257:15200-15203.
