The Role of Temperature Control in Emergency Medicine

More than 150 million visits are made to emergency rooms (ERs) across the U.S. annually. Barring paramedics, ERs are the first point of contact for a wide range of cases, from heat and cold-related conditions to advanced-stage illnesses. They were even at the forefront of the campaign against COVID-19 by isolating suspected infection cases.

Competent personnel are a given in an effective ER, but equally important are its facilities. One of them is temperature control, which ensures a comfortable environment for treating patients and maintaining situational awareness. If anything, its role in emergency medicine may be more than what public knowledge suggests.

Passive Cooling and Rewarming

Thermoregulation, the mechanism by which the body regulates its temperature at 98.6 +0.9°F (37 +0.5°C), is performed in several ways. The hypothalamus and its network of afferent and efferent sensors are responsible for keeping the ideal core temperature for maintaining homeostasis or overall stability.

Heat and cold-related diseases occur when thermoregulation can’t maintain the ideal core temperature on its own. While sweat cools the body, it also expends the body’s water and salt reserves. A lack of immediate replenishment can result in dehydration and, if the core temperature exceeds 105.8°F (41°C), an increased risk of cardiac arrest.

The same applies when the body produces heat, which dissipates to a cooler environment (as per thermodynamics). As heat is lost to the extreme cold, the body temperature drops. When it goes below 95°F (35°C), hypothermia sets in.

First responders to heat and cold-related emergencies initiate rapid cooling or rewarming during the patient’s transit. These include but aren’t limited to intravenous fluids and ice packs. For rewarming, first responders use heat packs, heated blankets, and air warmers.

That said, the immediate vicinity won’t always be an ideal place to administer treatment. Given the lethal risks of heatstroke and hypothermia, such cases should be brought to a controlled environment like the emergency room. Doing so allows medical practitioners to deliver more comprehensive treatment under the effects of passive cooling or rewarming.

In the absence of a permanent medical facility, a field hospital can simulate the same ideal conditions using a custom environmental control unit (ECU). Facility managers can specify the required specs from British thermal unit (Btu) output to mobility add-ons for their uses. Work with nothing short of an experienced ECU solutions provider for the best results.

Positive and Negative Pressure Isolation

Infectious diseases are as prevalent in emergency cases as other conditions. As such, ER personnel are trained in standard precautions to mitigate the spread of the likes of HIV or pneumonia. Examples include wearing surgical masks, disinfecting instruments and work surfaces, and maintaining an immunization schedule.

Despite these measures, handling patients with infectious diseases requires additional transmission-based precautions. One of these measures includes quartering patients in isolation rooms to lower the risk of healthcare-associated infections among other patients.

Isolation rooms mitigate infection spread through one of two methods: positive pressure and negative pressure. Rooms that maintain positive pressure prevent pathogens from entering, while rooms that maintain negative pressure prevent pathogens from escaping.

International guidelines suggest isolation rooms maintain a positive or differential pressure of at least 10 Pa (relative to the outside environment). This requires rapid air exchanges, which can cause discomfort to the patient due to resulting draughts. This is where active temperature control comes in.

Under ANSI/ASHRAE/ASHE 170-2008, isolation rooms must maintain a temperature range between 70 and 75°F (21.1 and 23.9°C) and a relative humidity of 60%. This is more or less the same temperature range in most parts of a hospital, which is ideal for ensuring sterility. Certain areas like intensive care units may adhere to different values.

Temperature control is also essential to compensate for heat transfer from the isolation room’s enclosure. The walls’ relatively high heat transfer coefficient translates to better heat flow into the room, which can be another source of discomfort for the patient (depending on the weather).

Drug Efficacy Preservation

Proper storage became a major topic of discussion during the rollout of the first batch of COVID-19 vaccines. As effective as their mRNA structure has been, they start degrading at temperatures upward of 77°F (25°C). In other words, normal climate, let alone extreme, poses a risk to the vaccine’s efficacy.

Prior to mass inoculations, the vaccines had to be stored in a storage solution capable of generating ultra-low temperatures. The Pfizer-BioNTech vaccine, for instance, demands cold storage conditions of around 100°F below zero (-73°C).

The effectiveness of temperature control isn’t limited to vaccines but also to medicines in general. Heat and cold alter the chemical structure of medications, not only rendering them ineffective but also, in some cases, harmful. For example, heat exposure causes aspirin to break down into vinegar and salicylic acid, which are known to irritate the stomach lining.

Preserving drug efficacy is as vital in emergency medical services (EMS) as maintaining readiness. To satisfy this, storage should adhere to guidelines under the United States Pharmacopoeia-National Formulary code.

• Insulated storage with active cooling and heating functionality
• Climate-controlled storage for portable medical carrying cases
• Facility-based storage for environmentally sensitive medications
• Time-temperature monitoring for specific medication packages
• Stock rotation plan based on the climate in the area of operation
• Best practices for parking EMS vehicles (e.g., in a garage, under the shade)

Similar to medication storage in other fields, EMS employs three tiers of storage.

• Room Temperature Storage: The majority of medications can be stored in regular storage media, such as medicine cabinets and portable carrying cases, provided room temperature (68-75°F or 20-23.9°C) can be maintained.
• Refrigerated Storage: Medications like injectables and liquid antibiotics must be stored in temperatures between 36 and 46°F (2.2 and 7.8°C). The storage can be in the form of onboard refrigerators or containers with frozen ice packs.
• Frozen Storage: This form of storage is often found in an EMS facility instead of an EMS vehicle due to the demand for below-zero storage conditions. Frozen storage usually operates as low as 5°F (-15°C), though it can be much lower for vaccines.

Proper temperature control allows first responders to avoid the worst-case scenario of administering ineffective treatment onsite. It also avoids costly drug wastage.

Medical Equipment Maintenance

In March, a hospital in Australia conducted dozens of surgeries on children using surgical equipment stored in a room with above-threshold humidity levels. Whereas the threshold is 30-60% relative humidity (RH), the room in said hospital registered at 70% RH.

None of the patients reportedly suffered any adverse effects, other than one patient who contracted an infection (it’s unclear if it was from the humid equipment). Surgeries for the rest of the day the issue was raised were rescheduled and completed without incident.

Healthcare authorities warn against improper RH levels in a clinical or hospital setting. A moist environment is a breeding ground for infectious entities and affects the function of lifesaving medical equipment. According to the Food and Drug Administration, medical devices and supplies exposed to high heat and RH levels might cause the following:

• Improper operation due to voltage fluctuations
• Decreased efficacy of lab reagents and test kits
• Decreased shelf-life of vital medical supplies
• Compromised packaging of sterile products

Temperature is a key factor in humidity. Warm indoor air holds a higher concentration of water vapor, which then traps more heat. As warm air drifts into a cooler environment, the vapor condenses into droplets. Without effective temperature control, the resulting damp patches can promote unwanted growths or corrode sensitive equipment components.

RH levels are rather consistent across areas of a clinic or hospital and change by season. Current recommendations are at 50-60% in colder months and 40-50% in warmer months. Under existing guidelines on temperature control, the ideal target temperature range is between 68 and 78.8°F (20 and 26°C).

It isn’t uncommon for healthcare facilities to lower RH to as low as 20%, accounting for the local climate (in this case, a dry climate). However, considering that ample climate control must also factor infection control into account, the absolute minimum can be somewhere around 35%. On the other hand, the maximum is almost always at 60%.

Ambient temperature is by no means the only factor influencing RH. Problems maintaining proper RH levels are mainly credited to issues with the HVAC system, such as insufficient heating and cooling or slow air exchange. The management is responsible for ensuring the HVAC system’s continued and optimal function. 

Key Takeaways

Temperature control contributes to effective emergency treatment in several ways.

• Adequate temperature helps manage heat and cold-related illnesses by facilitating passive cooling and rewarming, leading to favorable patient outcomes.
• Proper temperature control provides comfort to patients confined in positive and negative pressure isolation rooms, resulting in improved outcomes.
• Climate-controlled medicine storage preserves the efficacy of drugs and vaccines by protecting them from exposure to excess heat or cold.
• Maintaining sterility in medical devices and supplies relies on temperature control to limit infectious growth and breakdown of sensitive equipment parts.

Without this, saving lives in adverse environments may be next to impossible. Heatstroke and hypothermia would be more dangerous, or drugs and medical supplies wouldn’t work when paramedics need them to.

SAHIL BATRA

Hi, I’m the Founder and Developer of Paramedics World, a blog truly devoted to Paramedics. I am a Medical Lab Tech, a Web Developer and Bibliophiliac. My greatest hobby is to teach and motivate other peoples to do whatever they wanna do in life.