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Biomedical subjects

R MacDonald

Publications and source records attributed to R MacDonald.

At least 91 records · Page 5Linked to original sources

Comparison of extradural buprenorphine and extradural morphine after caesarean section.

Fifty-seven women received extradural morphine 3 mg, buprenorphine 0.18 mg or buprenorphine 0.09 mg after elective Caesarean section carried out under extradural bupivacaine. Supplementary sublingual buprenorphine was available on demand. Ten-centimetre visual analogue pain scores were completed regularly; emesis, pruritus and urinary retention were recorded for 24 h. Patients who received buprenorphine 0.09 mg had more pain, and required more supplementary analgesia, than those who received morphine 3 mg. Pain scores and analgesic requirements after buprenorphine 0.18 mg were not significantly different from either of the other two groups. Emesis was not significantly different in the three groups. More itching occurred after morphine 3 mg and buprenorphine 0.18 mg than after buprenorphine 0.09 mg; pruritus of the face, legs and perineum was more common after morphine than buprenorphine. Twenty-eight percent of patients without a urinary catheter developed retention of urine. Seventy-five to 84% of patients were satisfied with analgesia during the first day after operation. Analgesia and adverse effects were similar when morphine 3 mg or buprenorphine 0.18 mg was given extradurally after Caesarean section.

Buprenorphine↗

Obstetric anaesthetic services in the Yorkshire region.

A survey of obstetric anaesthetic services in the Yorkshire region, where about 44,500 deliveries take place annually, showed that inadequacies exist in the service to patients. A 24 hour epidural service is available in only nine of 19 consultant units, and in about seven units patients may have to wait up to half an hour for an anaesthetist to be available for an obstetric emergency. Additional consultant anaesthetic sessions are urgently required as well as centralisation of some units.

Anesthesia, Epidural↗

Expression of the c-myc protooncogene in human prostatic carcinoma and benign prostatic hyperplasia.

We have examined the level of c-myc transcripts in prostate tissue obtained from patients with both benign prostatic hyperplasia and adenocarcinoma of the prostate. A significantly higher level of c-myc transcripts is observed in patients with adenocarcinoma (P less than 0.05). In addition, a subset of patients with adenocarcinoma had levels of c-myc transcripts 2-fold higher than the mean level for this group. These preliminary results indicate that the investigation of c-myc levels as a prognostic indicator in prostatic carcinoma is warranted.

Acid Phosphatase↗

Obstetric epidural analgesia and postural hypotension.

Supine and erect arterial pressures were measured daily for six to seven days after delivery in 100 patients, of whom 50 had received epidural analgesia. There was no difference in the magnitude of postural hypotension between the epidural and control groups on any day after delivery, although in both groups the hypotension was greater during the first two days due almost entirely to changes in systolic arterial pressure. The incidence of dizziness on standing was similar in both groups (9%). Thus postural hypotension is no more common in women who have received epidural analgesia than in others. All patients should be helped out of bed after delivery, and any patient who experiences dizziness should have her blood pressure measured until the dizziness disappears.

Adolescent↗

Suxamethonium apnoea associated with plasmaphoresis.

A patient is reported who developed suxamethonium apnoea as a result of reduction in serum cholinesterase activity secondary to both pregnancy and plasmaphoresis. Had the enzyme studies been carried out before operation, regional rather than general, anaesthesia would have been used. In order to avoid the problems associated with prolonged paralysis we recommend the measurement of cholinesterase activity in all patients who have undergone plasmaphoresis and in whom anaesthesia involving the use of suxamethonium is contemplated.

Adult↗

Red cell 2,3-diphosphoglycerate and oxygen affinity.

The ease with which haemoglobin releases oxygen to the tissues is controlled by erythrocytic 2,3-diphosphoglycerate (2,3-DPG) such that an increase in the concentration of 2,3-DPG decreases oxygen affinity and vice versa. This review article describes the synthesis and breakdown of 2,3-DPG in the Embden-Meyerof pathway in red cells and briefly explains the molecular basis for its effect on oxygen affinity. Interaction of the effects of pH, Pco2, temperature and 2,3-DPG on the oxyhaemoglobin dissociation curve are discussed. The role of 2,3-DPG in the intraerythrocytic adaptation to various types of hypoxaemia is described. The increased oxygen affinity of blood stored in acid-citrate-dextrose (ACD) solution has been shown to be due to the decrease in the concentration of 2,3-DPG which occurs during storage. Methods of maintaining the concentration of 2,3-DPG in stored blood are described. The clinical implication of transfusion of elderly people, anaemic or pregnant patients with ACD stored blood to anaesthetically and surgically acceptable haemoglobin concentrations are discussed. Hypophosphataemia in association with parenteral feeding reduces 2,3-DPG concentration and so increases oxygen affinity. Since post-operative use of intravenous fluids such as dextrose or dextrose/saline also lead to hypophosphataemia, the addition of inorganic phosphorus to routine post-operative intravenous fluid may be advisable. Disorders of acid-base balance effect oxygen affinity not only by the direct effect of pH on the oxyhaemoglobin dissociation curve but by its control of 2,3-DPG metabolism. Management of acid-base disorders and pre-operative aklalinization of patients with sickle cell disease whould take account of this. It is known that anaesthesia alters the position of the oxyhaemoglobin dissociation curve, but it is thought that this is independent of any effects which anaesthetic agents may have on 2,3-DPG concentration. In vitro manipulation of 2,3-DPG concentration with steroids has already been carried out. Elucidation of the role of 2,3-DPG in the control of oxygen affinity may ultimately lead to iatrogenic manipulation of oxygen affinity in vivo.

Acid-Base Imbalance↗