Just as prospective differentiation between true emergencies and calls for subacute patients is critical to the delivery of prehospital care, retrospective differentiation is critical to research and quality improvement. Determining the acuity of patients based on the type of care they received could complement the vital-sign-based instruments currently popular, yet imperfect. The study aim was to create a consensus definition of time-dependent care and a list of time-dependent interventions in paramedicine.

The study was a Delphi approach consisting of four rounds of voting by a bi-provincial panel of 22 Canadian key informants representing medical first responders, paramedics, and physicians – first to agree on a definition of time-dependent care – then to categorize 29 clinical and 34 pharmacological interventions.

Based on the consensus definition of “A majority of patients who should receive the intervention, according to provincial protocols, would suffer a direct prejudice to their health or safety if the intervention, provided on its own, was not performed within eight minutes of the initial call,” the panel reached consensus on 52 of 63 interventions (82.5%), of which 17 (32.7%) were voted time-dependent (11 clinical [64.7%] and six pharmacological [35.3%]). Clinical interventions included airway suction or de-obstruction, cricothyrotomy, positive pressure ventilation, chest decompression, cardiopulmonary resuscitation, defibrillation, cardioversion, pacing, and hemorrhage control. Pharmacological interventions included medication classed as sympathomimetics, caloric agents, antiarrhythmic agents, anticonvulsants, or tranquilizers.

The panel reached a consensus on a definition of time-dependent care and used this to identify prehospital interventions that could serve as an instrument to improve care and system performance.

Thermal protective clothing (TPC) protects firefighters from physical threats associated with structural firefighting. However, it also limits the release of body heat generated, which can result in hyperthermia and dehydration. Despite the prevalence of winter structure fires in the United States, there is a paucity of cold-weather firefighting research.

This study documented physiological responses to moderate-intensity exercise in a cold environment while wearing TPC with the hypothesis that while exercising in firefighting TPC, a cold environment would maintain normal core body temperature and decrease extremity temperature compared to a thermal neutral environment.

Fourteen firefighters (two females; 30.9 [SD = 8.1] years) participated in both a thermal neutral (20°C) and cold (-8°C) condition simulation. Each subject was outfitted with a heart rate (HR) monitor, eight surface temperature sensors, and a core temperature (Tc) capsule prior to donning TPC. For each condition, subjects walked on a treadmill in an environmental chamber to simulate the common firefighting work intervals of two 20-minute sessions, with a short rest in between, followed by a 20-minute rehabilitation period. Body temperatures, HR, respiratory rate (RR), rate of perceived exertion (RPE), and thermal sensation, comfort, and preference were recorded during exercise and recovery.

Core temperature, HR, RR, and RPE increased during exercise in both conditions. Mean skin temperature (MST) rose during the thermal neutral condition but not during the cold condition. Overall, Tc (0.3 [SD = 0.4]°C; P = .0142), HR (26.3 [SD = 8.36] BPM), RR (3.56 [SD = 5.6] BPM), RPE (2.0 [SD = 1.9]), and MST (3.4 [SD = 1.2]°C) were all higher at the end of the neutral condition compared to the cold condition. During recovery, most measures returned to baseline after approximately five-to-20 minutes in both conditions, but they recovered more slowly in the thermal neutral condition.

Moderate-intensity exercise in TPC increased physiological and perceptual measures more in a thermal neutral environment than a cold environment. Recovery was faster following the cold condition. This may allow firefighters to work for longer durations or recover faster, possibly allowing for fewer crews on scene. However, this study did not account for the risk of other cold induced conditions due to prolonged exposure, such as frostbite. Further investigations should be conducted on cold weather firefighting and its impact on firefighters to establish guidelines and standard operating procedures.