Comparative before-after study of fever prevention versus targeted temperature management following out-of-hospital cardiac arrest

Background

International guidelines for neuroprotection following out-of-hospital cardiac arrest (OHCA) recommend fever prevention ahead of routine temperature management. This study aimed to identify any effect of changing from targeted temperature management to fever prevention on neurological outcome following OHCA.

Methods

A retrospective observational cohort study was conducted of consecutive admissions to an ICU at a tertiary OHCA centre. Comparison was made between a period of protocolised targeted temperature management (TTM) to 36 °C and a period of fever prevention.

Results

Data were available for 183 patients. Active temperature management was administered in 86/118 (72%) of the TTM cohort and 20/65 (31%) of the fever prevention group. The median highest temperature prior to the start of temperature management was significantly lower in the TTM group at 35.6 (IQR 34.9-36.2) compared to 37.9 °C (IQR 37.7-38.2) in the fever prevention group (adjusted p < 0.001).There was no difference in the proportion of patients discharged with Cerebral Performance Category 1 or 2 between the groups (42% vs. 40%, p = 0.88). Patients in the fever prevention group required a reduced duration of noradrenaline (36 vs. 46 h, p = 0.03) and a trend towards a reduced duration of propofol (37 vs. 56 h, p = 0.06).In unadjusted analysis, use of active temperature management (irrespective of group) appeared to be associated with decreased risk of poor outcome (OR = 0.43, 95% CI 0.23-0.78) but after adjustment for patient age, presenting rhythm, witnessed arrest and duration of CPR, this was no longer significant (OR = 0.93, 95% CI 0.37-2.31, p = 0.88).

Conclusion

Switching from TTM to fever prevention following OHCA was associated with similar rates of neurological outcomes, with a possible decrease in sedation and vasopressor requirements.

Relationship between rate of digestion of foods and post-prandial glycaemia

The amount of carbohydrate released at 1 and 5 h by digestion in vitro of 2 g carbohydrate portions of 14 foods by human digestive juices was compared with the area under the 2-h blood glucose response curve when 50 g carbohydrate portions were fed to groups of five to ten healthy volunteers. A significant relationship was found between the amounts of sugars and oligosaccharides liberated at 1 and 5 h and the food blood glucose area expressed as a percentage of the blood glucose area for 50 g glucose (r = 0.8627 and 0.8618, p less than 0.001). A significant relationship was also found between the glycaemic index and the food fibre content (p less than 0.02) and between the glycaemic index and the glucose trapping capacity of the foods (p less than 0.05). Legumes as a group liberated 56% less sugars and oligosaccharides (p less than 0.01) than the eight cereal foods over 5 h. It is suggested that such studies in vitro may help to identify food of use for diabetic patients, and at the same time throw further light on factors which affect post-prandial glycaemia.

Effect of acarbose on the 24-hour blood glucose profile and pattern of carbohydrate absorption

Acarbose (Bay g 5421) is a powerful alpha-glucoside hydrolase inhibitor of potential value in the treatment of diabetes and hypoglycemic dumping syndrome after gastric surgery. The extent of its use may be limited by symptoms produced by carbohydrate malabsorption. To minimize these, the action of low doses of acarbose on 24-h blood glucose profiles and hydrogen evolution have been studied on four ambulant volunteers on control diets, after exclusion of sucrose and also after addition of guar in an attempt to enhance the therapeutic effect. Replacement of dietary sucrose by starch abolished significant hydrogen evolution in the morning after low doses of acarbose but did not reduce its effectiveness in decreasing the mean three-meal blood glucose area by 41% (P less than 0.002). Addition of hydrated guar to this diet reduced the mean three-meal glucose area after acarbose further by 72% (P less than 0.001) but increased hydrogen evolution. The results suggest that acarbose will be both effective and acceptable given at low dose when the dietary carbohydrate is starch.

Scope and specificity of acarbose in slowing carbohydrate absorption in man

Fifty-gram carbohydrate tolerance tests were performed on healthy volunteers to test the activity and specificity of an alpha-glucoside hydrolase inhibitor, acarbose (BAY g 5421). Two hundred milligrams acarbose reduced the area under the blood glucose response curve by 89% (P less than 0.001) after sucrose by 80% (P less than 0.002) after starch, by 19% (N.S.) after maltose, with no effect on glucose. Breath hydrogen measurements indicated an almost complete malabsorption of the sucrose. At 50 mg acarbose, some reduction in blood glucose and insulin response to sucrose was still seen, but no significant hydrogen production. It is suggested that at lower doses, acarbose may prolong the time course over which carbohydrate is absorbed as does dietary fiber; as with fiber, it may be a useful adjunct to diabetic therapy.

Lack of effect of refining on the glycemic response to cereals

The blood glucose response to feeding whole and fiber-depleted cereals and cereal products was studied in healthy volunteers. No difference was seen between white and wholemeal bread and spaghetti or between white and brown rice. This lack of effect of cereal fiber on postprandial blood glucose levels suggests that the reported beneficial long-term effects of cereal-based, “natural,” high fiber diets on diabetic control must be due to other aspects of the diet or to a different effect of fiber.

Glycemic index of foods: a physiological basis for carbohydrate exchange

The determine the effect of different foods on the blood glucose, 62 commonly eaten foods and sugars were fed individually to groups of 5 to 10 healthy fasting volunteers. Blood glucose levels were measured over 2 h, and expressed as a percentage of the area under the glucose response curve when the same amount of carbohydrate was taken as glucose. The largest rises were seen with vegetables (70 +/- 5%), followed by breakfast cereals (65 +/- 5%), cereals and biscuits (60 +/- 3%), fruit (50 +/- 5%), dairy products (35 +/- 1%), and dried legumes (31 +/- 3%). A significant negative relationship was seen between fat (p less than 0.01) and protein (p less than 0.001) and postprandial glucose rise but not with fiber or sugar content.

Effect of guar crispbread with cereal products and leguminous seeds on blood glucose concentrations of diabetics

To compare the effect on blood glucose concentrations of guar incorporated into crispbreads with that of unprocessed high-fibre foods groups of four to six diabetics took a total of seven test breakfasts on separate days. By comparison with a breakfast of wholemeal bread and cheese, guar crispbread combined with bread reduced the area under the glucose response curve to 51% (p < 0.05); bread and soya beans reduced the area to 65% (p < 0.05); guar crispbread with soya beans to 25% (p < 0.002); and soya beans with lentils to 29% (p < 0.002). Porridge and cornflake breakfasts showed no difference. The favourable results with leguminous seeds may not make such meals more acceptable than meals of guar products, but a combination of leguminous seeds and guar may allow smaller and more acceptable amounts of both to be used.

Exceptionally low blood glucose response to dried beans: comparison with other carbohydrate foods

Normal volunteers took 50-g carbohydrate portions of eight varieties of dried legumes and 24 common foods drawn from grains, cereals and pasta, breakfast cereals, biscuits, and tuberous vegetables. Both the mean peak rise in blood glucose concentrations and mean area under the glucose curve of the subjects who ate beans were at least 45% lower than those of subjects who ate the other foods. These results suggest a potentially valuable role for dried leguminous seeds in carbohydrate exchanges for individuals with impaired carbohydrate tolerance.