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The critical thermal maximum (the colonic temperature of heat-induced convulsion and righting reflex loss) and thermoregulatory response of male mice were examined following I, exposure to colonic temperature (Tco) 42 degrees C; II, a single exposure to the critical thermal maximum (Tco 44 degrees C); AND III, acclimation at ambient temperatures of 15 or 30 degrees C for 14 days. The critical thermal maximum (CTM) was greater in 30 degrees C acclimated mice than 15 degrees C acclimated mice but was unchanged in mice surviving exposure to Tco 42 degrees C or the CTM. The heating time to apparent breakdown of thermoregulation coincident with an explosive rise in the Tco during exposure to ambient temperature 40.8 degrees C was increased (100%) during the 48-h period following exposure to Tco 42 degrees. It appeared that mice exposed to severe, short-term heat stress (Tco 42 degrees) undergo a compensatory increase in their thermoregulatory cooling capacity with little or no change in the upper temperature tolerated. The animals did, however, exhibit the capability for adaptive adjustments of the upper thermal limit during extended exposure to the more prolonged and less severe environmental heat stress of acclimation at 30 degrees C.

Background Venous thromboembolism (VTE) occurs frequently in critically ill patients without heparin prophylaxis. Although heparin prevents VTE, VTEs occur frequently despite prophylaxis. A higher heparin dosage may be more effective for preventing VTE. Methods A retrospective study was conducted using the Premier Incorporated Perspective Database to evaluate comparatively the effects of different heparin prophylaxis dosing strategies in the critically ill patient. Critically ill adult patients who were mechanically ventilated for at least 1 day and had an intensive care unit (ICU) length of stay of at least 2 days were included. Patients received 5000 units of heparin either twice/day or 3 times/day. The primary outcome was development of a new VTE. Key secondary outcomes included clinically important bleeding, thrombocytopenia, and mortality. Patients were propensity matched to control for confounding. Multivariable analysis was conducted for VTE risk factors. Results The study included 30,800 patients from 374 hospitals who were propensity matched by heparin dosage. New VTE occurred in 6.16% of patients treated with 3 times/day heparin versus 6.23% with twice/day heparin (p=0.8). No significant differences in the incidence of pulmonary embolism (0.91% vs 0.8%, p=0.29) or deep vein thrombosis (5.56% vs 5.70% p=0.59) were observed between the two types of heparin dosing. No differences were observed between the two types of heparin dosing in in‐hospital mortality (15.8% vs 15.15%), bleeding (0.23% vs 0.33%), or thrombocytopenia (5.19% vs 5.34%, p>0.08 for all), respectively. Risk factors associated with VTE included intraabdominal and urinary tract infections, loop diuretics, malnutrition, obesity, thrombocytopenia, paralytics, vasopressors, female sex, peripheral vascular disease, sepsis, neutropenia, and end‐stage renal disease. Antiplatelet therapy, heart failure, diabetes, and substance abuse were associated with reduced VTE (p<0.05 for all). Conclusions In critically ill patients, prophylactic dosing of heparin 3 times/day versus twice/day was not associated with differences in new VTE or safety outcomes. Several modifiable VTE risk factors were identified.

As-needed oral hydralazine is frequently prescribed for acute blood pressure lowering with administration thresholds often less than what are used to define acute severe hypertension. Many patients are prescribed PRN antihypertensive medication instead of being continued on their home regimens, and most patients do not have the intensity of their home regimens increased. Providers need to be educated about the use of PRN antihypertensive medication for the management of severe asymptomatic hypertension in the hospital setting.