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Biomedical subjects

M F James

Publications and source records attributed to M F James.

At least 91 records · Page 5Linked to original sources
PubMed1992

A comparison of spinal and epidural anaesthesia for hip arthroplasty.

Spinal and epidural anaesthesia were compared in 65 patients undergoing hip arthroplasty, with regard to the degree of sensory and motor blockade, cardiovascular effects, operating conditions, the dose of propofol required to produce satisfactory hypnosis, and complications. Epidural anaesthesia was successful in 30 patients using an initial dose of 15 ml of 0.5% bupivacaine, and spinal anaesthesia in 32 patients, using 4 ml 0.5% isobaric bupivacaine. The two techniques were similar with regard to the level of sensory blockade (T8), degree of hypotension and perioperative haemorrhage. Differences occurred in the degree of motor blockade (mean Bromage score of 1 in the spinal group vs 3.86 in the epidural group) (P less than 0.05), time to achieve maximal cephalad spread (13 min in the spinal group vs 21 min in the epidural group) (P less than 0.05) and the dose of propofol required to produce adequate hypnosis (1.95 mg.kg-1.hr-1 in the spinal group vs 2.89 mg.kg-1.hr-1 in the epidural group) (P less than 0.05). Only seven patients required urethral catheterization in this spinal group compared with 14 in the epidural group (P less than 0.05). Spinal anaesthesia also proved advantageous by providing better operating conditions for the surgeon, with a lower incidence of patient movement.

Adolescent↗
PubMed1992

Neutrophils from patients undergoing hip surgery exhibit enhanced movement under spinal anaesthesia compared with general anaesthesia.

The purpose of this research was to investigate whether the effects of regional anaesthesia on neutrophil migration differ from those due to general anaesthesia during major orthopaedic surgery in human patients. Eighteen patients underwent spinal or general anaesthesia (halothane or isoflurane) for surgery (six patients in each group). Blood samples were taken prior to induction of anaesthesia and after surgery was in progress for one hour. The movement of isolated neutrophils was measured in both samples in the chemotactic chamber toward lipopolysaccharide activated pooled serum. In addition plasma concentrations of catecholamines were determined in the blood samples. Neutrophils extracted from peripheral blood during spinal anaesthesia and surgery moved further towards a complement-derived attractant than neutrophils obtained from patients undergoing surgery under general anaesthesia with halothane or isoflurane and surgery (156.4 +/- 7.6 microns vs 114.3 +/- 6.1 microns or 119 +/- 8.4 microns respectively, P < 0.05). Increased concentrations of adrenaline were present in both general anaesthetic groups whereas the spinal group had lower concentrations than those prior to anaesthesia and surgery. It is considered unlikely that these differences in neutrophil reactivity are due to the direct effects of anaesthetic agents employed. The effects are likely to be the result of differing effects of spinal anaesthesia on the stress response or immunological mediators.

Adult↗
PubMed1992

Epidural lidocaine with sufentanil and epinephrine for abdominal hysterectomy under general anaesthesia: respiratory depression and postoperative analgesia.

The purpose of this investigation was to compare the analgesic actions and side-effects of a 50 micrograms epidural bolus of sufentanil and 50 micrograms epinephrine, with a control group receiving saline and epinephrine. The method employed was a prospective, randomised, double-blind trial involving 40 ASA I or II patients for total abdominal hysterectomy. All received 1.5% lidocaine with 1/200,000 epinephrine epidurally before operation, until a block to T4 was established. Patients were anaesthetised, their tracheas were intubated, and they were allowed to breathe spontaneously before administration of the test drug. Results showed that sufentanil prolonged the duration of local anaesthesia (198 +/- 35 min vs 174 +/- 29 min; P less than 0.05), and of analgesia (288 +/- 85 min vs 188 +/- 42 min; P less than 0.01). There was an increase in somnolence in the sufentanil group (9/20 vs 2/20; P less than 0.05). Glycopyrollate was given to 11/20 patients in the sufentanil group vs 1/20 in the control group (P less than 0.01) following bradycardia and hypotension. Clinical respiratory depression occurred in the sufentanil group; 5/20 patients required controlled ventilation following apnoea greater than 20 sec. It is concluded that epidural sufentanil causes considerable cardiorespiratory depression in the setting of general anaesthesia, and should be used with caution in the spontaneously breathing, anaesthetised patient.

Adult↗
PubMed1992

Propofol inhibits enzymatic degradation of alfentanil and sufentanil by isolated liver microsomes in vitro.

We have studied the effect of propofol on the enzymatic degradation of alfentanil and sufentanil utilizing isolated liver microsomes obtained from pig and human liver. Propofol inhibited dose-dependently the oxidative metabolic degradation of alfentanil and sufentanil by both microsomal preparations. The calculated concentration of propofol causing 50% inhibition of metabolic degradation (IC50) was 32.6 mumol litre-1 for alfentanil and 22.1 mumol litre-1 for sufentanil in pig liver microsomes. Similar values of inhibitory activity of propofol (IC50 values 62.8 and 52.9 mumol litre-1, respectively) were observed using human microsomes prepared from liver taken from an organ transplant donor. We suggest that propofol in clinically relevant concentrations interferes with oxidative metabolic degradation of alfentanil and sufentanil in the microsomal fraction of pig and human liver.

Alfentanil↗
PubMed1992

The laryngeal mask airway for intraocular surgery: effects on intraocular pressure and stress responses.

Tracheal intubation, performed routinely during general anaesthesia in patients undergoing intraocular surgery, may have adverse effects on cardiovascular function and intraocular pressure. This study assessed the suitability of the laryngeal mask airway (LMA) as a substitute for tracheal intubation. Intraocular and systemic pressor effects, heart rate changes and catecholamine concentrations were measured in two groups of 10 patients receiving standardized anaesthesia with either a tracheal tube (TT) or a LMA. There were significantly smaller changes in the pressor responses to insertion and in concentrations of catecholamines at critical times in the anaesthetic sequence in the LMA group. Mean (SEM) rate-pressure product was significantly smaller in the LMA group compared with the TT group after both insertion (8276 (730) vs 13307 (1348), P < 0.01) and removal (10152 (595) vs 14137 (1044), P < 0.01) of the airway device. The change in intraocular pressure was significantly less in the LMA group at all time points after airway instrumentation than that in the TT group, with the greatest difference after extubation (-2.3 (2.4) mm Hg vs 14.5 (3.4) mm Hg, P < 0.01).

Adult↗
PubMed1992

Intravenous sedation for ocular surgery under local anaesthesia.

Anterior segment ophthalmic surgery is commonly performed under local anaesthesia. In order to improve patient comfort, a variety of sedation techniques has been employed in the past. The object of this study was, firstly, to determine whether continuous intravenous sedation during surgery offered any advantages in patients premedicated with temazepam and metoclopramide, and, secondly, to compare midazolam to propofol for this purpose. Forty nine patients were randomly allocated to receive no intravenous sedation (n = 15), continuous propofol infusion (n = 17), or continuous intravenous midazolam infusion (n = 17) after peribulbar anaesthesia. Each technique provided cardiovascular and respiratory stability and allowed early recovery with minimal postoperative sequelae. Unexpected ocular field movement occurred more commonly in the patients receiving intravenous sedation, although statistical significance was not shown (p = 0.06). Significantly more patients in the intravenous sedation groups reported amnesia (p = 0.03). Patient acceptability was good irrespective of the technique used. This study suggests that continuous sedation using propofol or midazolam is not beneficial and should be avoided in ophthalmic patients who have received a simple premedication.

Aged↗
PubMed1992

Lidocaine and bupivacaine cardiorespiratory toxicity is additive: a study in rats.

The purpose of this study was to determine whether equipotent solutions of lidocaine, bupivacaine, or a mixture of these compounds infused at a fixed rate in anesthetized rats resulted in equivalent lethal cardiorespiratory toxicity and to establish whether the lethality of the individual drugs was additive. This was assessed by comparing the time to respiratory and circulatory arrest, determining the lethal doses of administered local anesthetic in each group, and ascertaining the concentration of lidocaine or bupivacaine, or both, at the time of circulatory arrest. The times to respiratory and circulatory arrest were similar in rats receiving either lidocaine (2%) or bupivacaine (0.5%) or a mixture of 1% lidocaine and 0.25% bupivacaine. The mean lidocaine-to-bupivacaine cumulative lethal dose ratio (3.36) and concentration ratio (2.33) were determined and used to calculate lidocaine equivalent values for bupivacaine data. Lidocaine equivalent cumulative lethal doses and plasma concentrations were similar in all three groups studied. This work suggests that the lethal cardiorespiratory toxicity of lidocaine and bupivacaine associated with intravenous infusion is additively toxic in rats.

Animals↗
PubMed1992

The effects of inhibition of plasma cholinesterase and hepatic microsomal enzyme activity on cocaine, benzoylecgonine, ecgonine methyl ester, and norcocaine blood levels in pigs.

We measured the blood levels of cocaine and its three major metabolites, benzoylecgonine, ecgonine methyl ester, and norcocaine, in three groups of male pigs weighing about 26 kg (25.75 +/- 0.25 kg) to determine the effects of inhibition of plasma cholinesterase and hepatic microsomal enzyme activity on cocaine metabolism. In addition, systemic elimination half-life, volume of distribution, and clearance of cocaine were calculated for the three groups. Group 1 pigs (n = 4) were pretreated with normal saline solution, group 2 pigs (n = 4) were pretreated with tetraisopropyl pyrophosphoramide, a specific plasma cholinesterase inhibitor, and group 3 pigs (n = 4) were pretreated with cimetidine, a hepatic microsomal enzyme inhibitor, all administered intramuscularly. Pigs were anesthetized with intravenous sodium thiopental; a carotid arterial cannula and an external jugular catheter were then inserted for the administration of cocaine and for blood sampling. Forty-five minutes later, when pigs were again completely awake, cocaine 3 mg/kg was given intravenously. Arterial blood samples were collected for the analysis of cocaine and cocaine metabolite levels just before and at 5, 10, 15, 30, 45, 60, 120, 180, and 1440 minutes after the administration of cocaine. Cocaine and cocaine metabolite blood levels were analyzed with high-pressure liquid chromatography methods and plasma cholinesterase activity was measured with a colorimetric method. The blood levels of cocaine and cocaine metabolites were significantly different among the three groups (p less than 0.05, analysis of variance). Statistically significant differences in half-life, volume of distribution and clearance were also seen among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Orthotopic liver transplantation at Groote Schuur Hospital.

We present data on 10 patients (5 men and 5 women, aged 21-56 yrs) with end-stage liver disease or tumour who underwent orthotopic liver transplantation at Groote Schuur Hospital between October 1988 and June 1991. Standard surgical techniques were used for procuring the donor liver, the recipient hepatectomy and the implantation of the liver. The venovenous bypass method was used in all but 2 patients. Postoperative immunosuppression was usually achieved with cyclosporin, azathioprine and low-dose steroids. Six patients were treated with prophylactic OKT3. Rejection episodes were treated with bolus doses of intravenous steroids. The indications for liver transplantation included chronic active hepatitis progressing to cirrhosis (5), biliary cirrhosis in association with inflammatory bowel disease (1), sclerosing cholangitis (2), alpha 1-antitrypsin deficiency (1), and tumour (1). All patients with chronic liver disease had experienced at least one complication, examples of which included encephalopathy, bacterial peritonitis, ascites, variceal bleeding and septicaemia. Serious postoperative complications included acute rejection of the transplanted liver, renal and liver failure that responded to intensive care support and medical management. One patient died on the 11th postoperative day with complications of bleeding oesophageal ulcer, shock and fungaemia. The remaining patients are alive and well 1-31 months after transplantation.

Adult↗
PubMed1992

Anaesthesia for liver transplantation. The Groote Schuur Hospital experience.

In October 1988 the orthotopic liver transplantation programme recommenced at Groote Schuur Hospital. The experience gained from our first 10 patients is described here. Anaesthesia for this type of surgery is demanding given the long duration of the operation and the severe haemodynamic and physiological alterations that can occur. A rapid sequence induction is usually performed and anaesthesia maintained with fentanyl and isoflurane. Dopamine and mannitol are used for renal protection. Extensive monitoring of haemodynamics, biochemistry, coagulation and temperature is essential. A rapid infusion device is mandatory as massive blood loss may occur. All patients were electively ventilated in the surgical intensive care unit postoperatively. One patient died 11 days postoperatively. The remainder are well at the time of writing.

Anesthesia↗
PubMed1991

Phaeochromocytoma. A report of 10 patients.

A spectrum of presentation of phaeochromocytoma in black South Africans is described. Ten patients were reviewed over a 9-year period. Sweating, headache, and palpitations were prominent symptoms in 9 patients; postural dizziness occurred in 5; gastro-intestinal symptoms in 7; diabetes in 3; and hypertension in all. One patient developed a phaeochromocytoma crisis, characterised by hypotension and pulmonary oedema, before operation. One woman presented in pregnancy. Urinary vanillylmandelic acid was elevated in 9 out of 10 subjects tested; plasma catecholamines were elevated in 6 out of 6 tested. Computed tomography detected 7 adrenal tumours and 3 paragangliomas. All patients were stabilised pre-operatively with alpha- and/or beta-receptor blockers. Intraoperative pressor crises were controlled with sodium nitroprusside, phentolamine, or magnesium sulphate infusions. At operation all tumours appeared benign, each was successfully removed, and the diagnosis confirmed on histological examination. There was no operative mortality. Two patients had residual hypertension. This study highlights the various challenges presented by this catecholamine-producing tumour.

Adolescent↗
PubMed1991

Intrapleural bupivacaine analgesia in chest trauma: a randomized double-blind controlled trial.

A randomized double-blind study was undertaken to investigate whether 0.25 per cent bupivacaine administered intrapleurally is an effective and reasonably safe method of obtaining analgesia in patients with thoracic injuries. A total of 120 patients complaining of pain after chest injury were entered into the trial. All had thoracostomy tubes already in situ. Of 60 patients who were given the test dose of bupivacaine intrapleurally, 37 obtained satisfactory pain relief for 2 or more hours compared with only 9 of 60 patients who received saline P less than 0.000001). Duration of analgesia in the test group (mean 3.9 h) was significantly longer than that in the control group (mean 0.9 h) P less than 0.005). There were no important side-effects attributable to the bupivacaine administered. We conclude that intrapleural bupivacaine is an effective and reasonably safe method for obtaining analgesia in patients who have chest drain tubes inserted.

Adolescent↗
PubMed1991

Attenuation of the pressor response to tracheal intubation in hypertensive proteinuric pregnant patients by lignocaine, alfentanil and magnesium sulphate.

The pressor response to intubation is known to be exaggerated in patients with gestational proteinuric hypertension (GPH). The effect of pretreatment with lignocaine 1.5 mg kg-1, magnesium sulphate 40 mg kg-1 or alfentanil 10 micrograms kg-1 on this pressor response was studied in 69 patients with moderate to severe GPH. Systolic arterial pressure exceeded baseline values for the first 5 min after tracheal intubation in the lignocaine group, with a peak increase of 31.6 (SEM 3.6) mm Hg at 2 min after intubation, but no mean increase in pressure occurred in the two other groups. Following intubation, six of 24 mothers in the alfentanil group, six of 21 in the lignocaine group and one of 24 in the magnesium group (P less than 0.05) exhibited a systolic arterial pressure (SAP) greater than 180 mm Hg sustained for 2 min or more. Alfentanil caused the least change in heart rate, but resulted in significant fetal depression.

Alfentanil↗
PubMed1991

Priming of pancuronium with magnesium.

Magnesium inhibits the release of acetylcholine from the motor nerve terminal and thus potentiates the action of the non-depolarizing neuromuscular blocking drugs. We have examined the possibility that this effect might enhance the speed of onset of non-depolarizing block with pancuronium. Following the administration of pancuronium 100 micrograms kg-1, 95% depression of thumb twitch occurred in 68.3 (SD 25.9) s in magnesium-pretreated subjects and in 73.7 (19.5) s in a group given a priming dose (10 micrograms kg-1) of pancuronium. Tracheal intubation was performed after 97.8 (22.5) s in the magnesium group and in 121.0 (37.5) s in the control group (ns). It is concluded that pretreatment with magnesium does not usefully increase the speed of onset of action of pancuronium.

Adult↗
PubMed1991

Attenuation of the pressor response to tracheal intubation by magnesium sulphate with and without alfentanil in hypertensive proteinuric patients undergoing caesarean section.

The pressor response to tracheal intubation is known to be exaggerated in patients with gestational proteinuric hypertension (GPH). We have studied the effect of pretreatment with magnesium sulphate 40 mg kg-1 or 30 mg kg-1 with alfentanil 7.5 micrograms kg-1 on this pressor response in 38 patients with moderate to severe GPH. The magnesium-alfentanil combination produced better control of arterial pressure and heart rate than magnesium alone, although both techniques provided good cardiovascular control. There was no significant difference in fetal outcome between groups. Both pretreatment methods produced satisfactory control of catecholamine release.

Adult↗