Shock index (SI) is defined as the heart rate (HR) divided by systolic blood pressure (SBP). It has been studied in patients either at risk of or experiencing shock from a variety of causes: trauma, hemorrhage, myocardial infarction, pulmonary embolism, sepsis, and ruptured ectopic pregnancy. While HR and SBP have traditionally been used to characterize shock in these patients, they often appear normal in the compensatory phase of shock and can be confounded by factors such as medications (eg, antihypertensives, beta-agonists). SI >1.0 has been widely found to predict increased risk of mortality and other markers of morbidity, such as need for massive transfusion protocol activation and admission to intensive care units. Recent research has aimed to study the use of SI in patients immediately on arrival to the emergency department (ED). In this review, we summarize the literature pertaining to use of SI across a variety of settings in the management of ED patients, in order to provide context for use of this measure in the triage and management of critically ill patients.
Simulation-based mastery learning using a substantial asynchronous component is an effective way for senior medical students to learn and retain EM clinical skills. This method can be adapted to other skill training necessary for residency readiness.
Context: Carbohydrate ingestion has recently been associated with elevated core temperature during exercise in the heat when testing for ergogenic effects. Whether the association holds when metabolic rate is controlled is unclear. Such an effect would have undesirable consequences for the safety of the athlete.Objective: To examine whether ingesting fluids containing carbohydrate contributed to an accelerated rise in core temperature and greater overall body heat production during 1 hour of exercise at 306C when the effort was maintained at steady state.Design: Crossover design (repeated measures) in randomized order of treatments of drinking fluids with carbohydrate and electrolytes (CHO) or flavored-water placebo with electrolytes (PLA). The beverages were identical except for the carbohydrate content: CHO 5 93.7 6 11.2 g, PLA 5 0 g.Setting: Research laboratory.Patients or Other Participants: Nine physically fit, endurance-trained adult males.
Intervention(s):Using rectal temperature sensors, we measured core temperature during 30 minutes of rest and 60 minutes of exercise at 65% of maximal oxygen uptake (V O 2 max) in the heat (30.66C, 51.8% relative humidity). Participants drank equal volumes (1.6 L) of 2 beverages in aliquots 30 minutes before and every 15 minutes during exercise. Volumes were fixed to approximate sweat rates and minimize dehydration.Main Outcome Measure(s): Rectal temperature and metabolic response (V O 2 , heart rate).Results: Peak temperature, rate of temperature increase, and metabolic responses did not differ between beverage treatments. Initial hydration status, sweat rate, and fluid replacement were also not different between trials, as planned.Conclusions: Ingestion of carbohydrate in fluid volumes that minimized dehydration during 1 hour of steady-state exercise at 306C did not elicit an increase in metabolic rate or core temperature.Key Words: rectal temperature, glucose, fructose, thermoregulation, heat stress
Key PointsN Fluid ingestion is a strategy that minimizes dehydration and attenuates the rise in core temperature by maintaining plasma volume. Carbohydrate-electrolyte drinks are often used for this strategy.N The gradient between body temperature and the environment may also be a factor when investigators determine if the effect of extreme environmental conditions, exercise duration and intensity, carbohydrate dose, and compromised hydration status should be considered.N Under controlled conditions, elevated core temperature did not appear to be a risk when beverages containing carbohydrate were ingested at a rate sufficient to maintain hydration during steady-state exercise. E xercise in warm, humid environments increases core body temperature and can cause heat storage in the body. Heat storage increases sweat rate, which may induce dehydration. Independent of hydration status, severe heat storage promotes fatigue and increases the risk of exertional heat stroke. Fluid ingestion is a strategy that minimizes dehydration and attenuates the rise in core temperature by main...
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