Intensive care—a medical audit

A 4-year audit of one Intensive Care Unit, during which time 1718 patients were admitted, shows that allocating 1% of all acute beds for intensive care purposes is not adequate. This is reflected by the high mortality among the patients discharged from the unit. Sophisticated monitoring equipment led to a marked improvement in mortality rates in each group to which it was applied. Simple to use, automated, biochemical equipment was very cost effective for blood gas measurement but less so for electrolyte determinations. Intensive care is very labour intensive, but the cost benefit in terms of lives saved is large. It is suggested that audits of this type help to identify the consequences, including adverse consequences, of decisions by administrators.     

NITROUS OXIDE INHALATION DOES NOT INFLUENCE PLASMA CONCENTRATIONS OF (3-ENDORPHIN OR MET-ENKEPHALIN-LIKE IMMUNOREACTIVITY

The possibility that nitrous oxide releases endogenous opioidpeptides into the circulation has been tested in 10 pain-free,unstressed volunteers breathing 30% nitrous oxide in oxygen.Despite achieving plateau concentrations in venous blood, accompaniedby subjective effects, there were no significant changes inplasma concentrations of immunoreactive ß-endorphin,methionine-enkephalin or ACTH. These results indicate that,in the absence of nociceptive input, the effects of the inhalationof nitrous oxide are unrelated to alterations in peripheralconcentrations of these endogenous opioid peptides. ^*Present address: Hospital for Sick Children, Melbourne, Australia.     

CORTICOTROPHIN RELEASING FACTOR: RESPONSES IN NORMAL SUBJECTS AND PATIENTS WITH DISORDERS OF THE HYPOTHALAMUS AND PITUITARY

Synthetic CRF-41 has been given to 43 patients with hypothalamic, pituitary or adrenal diseases and contrasted with the responses in 20 normal subjects. In the normal subjects the mean increment in serum cortisol (± SE) was 276 ± 38 nmol/l; the increments showed a significant negative correlation with the basal serum cortisol levels (r= -0·56; P<0·02). The mean peak serum cortisol was 662 ± 34 nmol/1 and the mean peak corticosterone was 28·6 ± 3·8 nmol/1. There was a significant positive correlation between the peak serum corticosterone and cortisol concentrations (r= 0·84; P<0·0001). Dexamethasone pretreatment abolished the rise in cortisol in response to CRF-41. The peak serum cortisol following CRF-41 was not significantly different between the normal subjects and those patients with pituitary disease who had normal cortisol responses to insulin-induced hypoglycaemia. However, in individual patients the peak cortisol levels induced by hypoglycaemia were greater than, but significantly correlated with, those induced by 100 μg of CRF-41. Seven patients were ACTH deficient in response to hypoglycaemia, and of these six responded normally to CRF-41. Only one of these patients had a lesion clearly originating in the hypothalamus; four had pituitary tumours with suprasellar extensions and the remaining patient had idiopathic GH and ACTH deficiency. Our data suggest that these patients have a functional defect of ACTH secretion due to the failure of CRF to reach the corticotroph. Of the four patients with pituitary-dependent Cushing's disease who were on no treatment at the time of testing, three showed an exaggerated and one a normal response to CRF-41. These normal or enhanced responses of hypercortisolaemic patients with Cushing's syndrome contrast with the complete inhibition of the responses to CRF-41 in normal subjects given dexamethasone. In the treated patients with Cushing's syndrome     

SOME EFFECTS OF ANAESTHESIA AND SURGERY ON CARBOHYDRATE AND FAT METABOLISM

The effects of emotional stress, nitrous oxide and halothaneanaesthesia, a 1-minute period of hypoxia, and surgery, on theblood sugar, plasma free fatty acids (FFA) and insulin wereinvestigated. The emotional stress of being brought to the operatingtheatre and the stress of surgery seem to be more importantthan anaesthesia in causing a rise in blood sugar and plasmaFFA. There was a corresponding fall in levels of plasma insulin.The infusion of Phentolamine in two patients did not preventthe failure of insulin response to injected glucose during surgery.The clinical significance of this temporary state of glucoseintolerance is discussed. ^*Present address: Department of Biochemistry,Bristol University.     

A comparative study of the effects on colon function caused by feeding ispaghula husk and polydextrose

Polydextrose is a new soluble food ingredient which cannot be digested by intestinal enzymes and so may affect colonic function. Studies in healthy volunteers compared the effects of diet supplementation with 30 g/day polydextrose, a standard dose of 7 g/day ispaghula and two mixtures containing 2 g/day ispaghula with either 30 g/day polydextrose or 10 g/day polydextrose with a control period. During the 10-day periods, the mass, frequency and consistency of faeces were assessed as well as the whole-gut transit time, ease of defaecation, flatulence and palatability of the preparations. All preparations significantly increased the weekly faecal mass above control values (P less than 0.05) but there were no significant differences between the preparations. Transit time and stool frequency were not affected significantly by any of the preparations (P greater than 0.05). Both preparations supplying 30 g/day polydextrose softened stool consistency equally but the other preparations had no effect. All preparations caused flatulence and other gas-related problems but polydextrose caused more than ispaghula, even at the lowest dose of 10 g/day. More volunteers preferred taking the polydextrose drinks than the sachets of ispaghula which formed a viscous drink with water. Despite superior palatability and equally effective stool bulking, polydextrose is unlikely to be an alternative laxative to ispaghula because of the unacceptable levels of flatulence.     

A POSSIBLE MEANS OF RAPID COOLING IN THE EMERGENCY TREATMENT OF MALIGNANT HYPERPYREXIA

A possible means of rapid cooling in the emergency treatmentof malignant hyperpyrexia, peritoneal dialysis using a colddialysate, is described. Experimental observations in a youngman on a regular peritoneal dialysis regime showed that significantheat extraction can be obtained when either a cool (20 C) orcold (9 C) dialysis fluid is used. The maximum heat exchangeobserved was 17.5 kj/min when 2 litre of cold dialysate wasinstilled for a mean time of 10 min. This rate of heat exchangeis within the 10–40 kj/min range of excess heat productionthat occurs in malignant hyperpyrexia. Since peritoneal dialysisis, technically, a very quick and simple procedure, it is suggestedthat it might play a very useful role in the emergency treatmentof malignant hyperpyrexia. The dialysis treatment would alsocorrect some of the biochemical disturbances that occur in thiscondition.