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Biomedical subjects

A L Forrest

Publications and source records attributed to A L Forrest.

14 recordsLinked to original sources

The clinical and metabolic responses to early surgical treatment for hyperthyroid Graves' disease: a comparison of three pre-operative treatment regimens.

We have compared the clinical and metabolic responses of three groups of patients undergoing subtotal thyroidectomy for hyperthyroid Graves' disease. These patients were prepared for surgery with propranolol alone, propranolol plus potassium iodide or the long acting beta-adrenoceptor antagonist nadolol plus potassium iodide. Pre-treatment with potassium iodide reduced serum T4 to normal or subnormal in all patients. Patients in the propranolol group had significantly higher pulse rates and temperatures after operation and one patient developed an exacerbation of the hypermetabolic state. The perioperative rise in serum cortisol and blood glucose was delayed in patients in the propranolol group and this was also noted in one severely hyperthyroid patient on propranolol + potassium iodide. Nadolol was administered once daily as compared to multiple daily doses with propranolol. Despite this, plasma nadolol levels were consistently higher throughout the perioperative period while propranolol levels in patients on both propranolol alone and propranolol + potassium iodide were highly variable and sometimes undetectable. We conclude that, in the rapid preparation of patients with hyperthyroid Graves' disease for surgery, the combination of nadolol + potassium iodide has significant advantages over the other two regimens.

Adult↗

Patient monitoring in the operating theatre. A comparison of practice between 1976 and 1983.

The vital importance of patient monitoring during anaesthesia is well recognised. There is little information available, however, on the actual practice of instrumental monitoring in the operating theatre. This study examined present-day practice and compared it with that of 1976. The main findings were an increase in frequency of electrocardiographic monitoring, especially for non-major surgery, and a smaller increase in blood pressure recording. Monitoring of other variables remained essentially unchanged. Possible reasons for this are given and suggestions made for improvements.

Adolescent↗

Beta-adrenoceptor blockade and anaesthesia for thyroidectomy.

The administration of beta-adrenoceptor blocking drugs in the pre-operative preparation and operative management of thyrotoxic patients undergoing subtotal thyroidectomy is reviewed. Particular reference is made to some of the recent advances and it is emphasised that there has been a considerable reduction in the incidence of problems following judicious use of these drugs. The choice of anaesthetic technique employed for thyroidectomy is less important than the degree of control of thyrotoxicosis by the beta-adrenoceptor blocking drug. Propranolol has proved safe and effective for the majority of patients. The longer acting agent nadolol is easier to administer, particularly in the peri-operative period. Patients are rendered less thyrotoxic and safety thereby enhanced by adding potassium iodide for 10 days preoperatively. The combination of nadolol and potassium iodide offers real advantages in the preparation of the thyrotoxic patient for surgery.

Adrenergic beta-Antagonists↗

Nadolol and potassium iodide in combination in the surgical treatment of thyrotoxicosis.

With the two aims of rapidly reducing circulating thyroid hormone levels and controlling the symptoms of thyrotoxicosis, we have prepared 17 thyrotoxic patients for subtotal thyroidectomy, using a combination of potassium iodide administered for 10 days and the long acting beta-adrenoceptor antagonist nadolol. All 17 patients had normal serum thyroxine levels after 10 days of such treatment although 10 still showed elevation of serum tri-iodothyronine and considerable elevation in the most severely toxic patient. All patients were, however, clinically euthyroid preoperatively. Nadolol was administered once daily, hence avoiding the problems of drug administration in the immediate postoperative period, and plasma nadolol concentrations were high throughout the perioperative period. Serum thyroxine and tri-iodothyronine levels were significantly lower and reverse tri-iodothyronine levels higher 24 h postoperatively than before operation. All patients remained stable throughout the perioperative period. We conclude that this regimen has a number of advantages in the preparation of patients for thyroidectomy, in reducing the degree of thyrotoxicosis, in convenience of drug administration and in ensuring adequate circulating concentrations of beta-adrenoceptor antagonist whilst still retaining a relatively short preoperative phase of drug treatment.

Adrenergic beta-Antagonists↗

Propranolol in the surgical treatment of hyperthyroidism, including severely thyrotoxic patients.

The perioperative course of 44 hyperthyroid patients prepared for surgery with propranolol alone, including 11 with severe thyrotoxicosis was compared to that of 20 euthyroid patients prepared for surgery with carbimazole. Conventional propranolol at a dosage of 160 mg/day was frequently insufficient to produce a high degree of beta-adrenergic blockade, particularly in severely thyrotoxic patients. A greater than 25 per cent reduction in sitting pulse rate was associated with a high degree of beta-blockade. The clinical course of patients with mild or moderate thyrotoxicosis was similar to that of the patients prepared with carbimazole. In contrast, the course of severely thyrotoxic patients was complicated and, in addition to a higher preoperative propranolol dosage, these patients commonly required supplemental propranolol after operation. Although thyroid crisis did not occur in any patient, we cannot recommend the use of propranolol alone for the severely thyrotoxic patient.

Adult↗

Altered endocrine response to partial thyroidectomy in propranolol-prepared hyperthyroid patients.

The endocrine response to partial thyroidectomy in a group of twenty hyperthyroid patients prepared with propranolol alone was compared to that of a matched control group of ten euthyroid patients. In propranolol-prepared patients the glucose response to surgery was reduced (P less than 0.05) for up to 4 h post-operatively and biochemical hypoglycaemia was noted in one patient. Both thyroxine and triiodothyronine (T3) fell significantly, associated with a marked rise in reverse T3. Growth hormone levels were higher (P less than 0.05) both pre- and post-operatively in propranolol-prepared patients, whereas prolactin levels, although similar pre-operatively, were lower (P less than 0.05) in these patients post-operatively. Cortisol and ACTH levels were lower (P less than 0.05) both before and following thyroidectomy in propranolol-prepared patients. These results suggest that the endocrine response to surgical stress is markedly altered in propranolol-prepared hyperthyroid patients.

Adrenocorticotropic Hormone↗

Reports by anaesthetists to procurators-fiscal: analysis of "anaesthetic deaths" over 10 years in four Scottish teaching hospitals.

Review of 489 "anaesthetic deaths" reported to procurators-fiscal over 10 years disclosed only 30 that were thought to justify such reporting. Most of the remainder occurred in patients so desperately ill at the time of operation that death was expected. Postmortem examinations ordered by the Crown authorities in nearly all cases were probably largely unrewarding and mostly unnecessary. The results suggest that the present regulation on reporting should be revised to focus more attention on the few deaths that occur in patients who have no apparent contraindication to anaesthesia or operation.

Adult↗

Patient monitoring in the operating theatre.

Anaesthetised patients are monitored to ensure their safety. Simple clinical observations must not be replaced by electronic instruments--these provide an extension of the clinical senses. The choice of parameters for monitoring is discussed. The design of the Ninewells main operating theatre suite is described. An 8-channel bourne in the base of the theatre table conveys patient signals to a 4-channel recorder in a monitoring laboratory. Outputs are displayed on a wall mounted display in theatre. Two-way speech intercommunication exists with monitoring technician and students.

Anesthesia↗