Acta anaesth. stand. 1977, 21, 395-399
Glomerular Filtration Rate during Halothane Anaesthesia and Epidural Analgesia in Combination with Halothane Anaesthesia B. H. JENSEN,P. BERTHELSEN and J. BROCHNER-MORTENSEN Departments of Anaesthesiology, Clinical Physiology and Obstetrics and Gynaecology, Aalborg Sygehus, Aalborg, Denmark
Pre- and peroperative determination of glomerular filtration rate (GFR) was performed in nine patients operated during light halothane anaesthesia (group A) and in nine patients operated during epidural analgesia in combination with light halothane anaesthesia (group B). In group A, the mean GFR decreased insignificantly by 7% and the mean arterial blood pressure increased significantly by 10%. In group B, the mean GFR decreased significantly by 19% and the mean arterial blood pressure decreased significantly by 15%. I t is suggested that the difference in change in GFR between the two groups was caused by differences in mean arterial blood pressure.
Received 24 November, accepted f o r publication 28 December 1976
Nearly all general anaesthetics cause a this with the effect on GFR of light halothane reduction of glomerular filtration rate (GFR) anaesthesia alone. (PAPPER& PAPPER1964). Halothane is one of the most commonly used anaesthetics for general anaesthesia, and its effect on GFR has MATERIAL AND METHODS been intensively investigated (MAZZEet al. Patients 1963, DEUTSCHet al. 1966 and LUNDBERGPre- and peroperative determinations of GFR in 18 1967). Halothane decreases GFR propor- females who underwent an uncomplicated total tionally to the depth of anaesthesia, and the hysterectomy formed the basis for the present study. decrease in GFR during light halothane These patients fulfilled the following criteria: age less anaesthesia is minimized by hydration (BARRY than 65 years; body weight less than 90 kg; no signs of renal, cardiovascular or endocrine disorders; blood et al. 1964). loss less than 1000 ml during operation; and a calcuGFR during epidural analgesia has lated positive urine flow in both clearance periods received less attention; in the only study we during operation. The patients were randomly allocated to two are aware of (KENNEDY et al. 1969), a mean groups: Group A consisted of nine patients who decrease in GFR of 9% was found. received light halothane anaesthesia. Group B conEpidural analgesia in combination with sisted of nine patients who received epidural analgesia general anaesthesia is increasingly used, in combination with light halothane anaesthesia. particularly in urological and gynaecological surgery. Hitherto, the effect on GFR of this Anaesthesia All patients were premedicated with 50 mg pethidine type of anaesthesia has not been studied. The purpose of the present study was to and 0.5 mg atropine. In group A, the anaesthesia was investigate the effect on GFR of lumbar induced with 0.5 mg atropine and 250 mg thiopentone intravenously. The intubation was facilitated epidural analgesia in combination with a by 75 mg suxamethonium intravenously. The anaeslight halothane anaesthesia, and to compare thesia was maintained in a non-rebreathing system
u. H. JENSEN, P.
BERTHELSEN AND J. BROCHNER-MORTENSEN
with 0.5% halothane in a n oxygen-nitrous oxide mixture in the proportion 1 :2. Muscle relaxation was maintained by pancuronium. The pulmonary ventilation was controlled by an Engstrom ER 300 respirator, and it was adjusted to keep the arterial carbon dioxide within normal range. From the induction of anaesthesia the patients were hydrated intravenously by isotonic saline 10 ml per kg body weight per hour, and this was continued during operation. During anaesthesia, EGG and rectal temperature were monitored. Blood pressure was measured every 5 min using a standard sphygmomanometer, and the mean arterial blood pressure (MABP) was estimated as diastolic blood pressure plus 30% pulse amplitude. In group B, the epidural analgesia was performed in the lateral position: an epidural catheter was inserted via a Tuohy needle a t the L4-5 interspace, and passed 5 cm in the cranial direction. An epidural block to a T 5 sensory level was achieved with 20-28 ml 0.5% bupivacaine. Following control of the extension of the epidural block, the patients were handled just like group A. The blood loss was estimated by weighing swabs, and it was continuously replaced by Macrodex" in saline. No patients in group A and only one patient in group B received blood transfusions. Groups A and B were comparable with respect to age, blood loss, decrease in rectal temperature, time from induction of general anaesthesia to beginning of first clearance period, time from start of operation to beginning of first clearance period, and duration of operation (Table I ) .
Measurenient of GFR The GFR was determined as the renal plasma clearance of [slCr] EDTA. GFR was determined 1-3 days prior to operation from the total [51Cr] EDTA plasma clearance, as measured by a simplified single injection method (BROCHNER-MORTENSEN 1972), and corrected
for extra renal clearance of [51Cr] EDTA (BROCHNERMORTENSEN & RODBRO 1976b). During operation, GFR was determined twice by the continuous infusion technique. The first of two clearance periods (each lasting 30 rnin) started about 1 hour after the priming dose of [51Cr] EDTA was given, and the intravenously sustained infusion of ["Gr] EDTA commenced. Urine was collected through a three-way bladder catheter. At the end of each period, the bladder was rinsed with 200 ml isotonic saline and thoroughly emptied by means of air insufflation and direct gentle bladder pressure. Blood samples were drawn at the beginning and the end of each clearance period through a catheter introduced into the femoral artery. For calculation of clearance, the concentration of ["Cr] EDTA in plasma in the middle of the clearance period minus 4 or 7 min (at urine flow > 1 ml/min and < 1 nil/min, respectively) was used. The activity of [51Cr]EDTA in plasma- and urine samples was measured in a well scintillation counter, preset for 10,000 counts.
Statistical analysis Within each group, the change in GFK and MABP was tested by use of the 1-test for paired comparisons. The differences between groups were tested by Student's t-test, with the exception of MABP, where the Mann-Whitney test was employed.
RESULTS The results are summarized in Table 2. Groups A and B were comparable with respect to preanaesthetic GFR and MABP. In group A, the mean decrease in GFR was 7%; this change was not significant (0.2