Bradycardia in a newborn with accidental severe hypothermia: treat or don’t touch? A case report

Background Hypothermia significantly affects mortality and morbidity of newborns. Literature about severe accidental hypothermia in neonates is limited. We report a case of a neonate suffering from severe accidental hypothermia. An understanding of the physiology of neonatal thermoregulation and hypothermia is important to decide on treatment. Case presentation A low-birth-weight newborn was found with severe accidental hypothermia (rectal temperature 25.7 °C) due to prolonged exposure to low ambient temperature. The newborn presented bradycardic, bradypnoeic, lethargic, pale and cold. Bradycardia, bradypnea and impaired consciousness were interpreted in the context of the measured body temperature. Therefore, no reanimation or intubation was initiated. The newborn was closely monitored and successfully treated only with active and passive rewarming. Conclusion Clinical parameters such as heart frequency, blood pressure, respiration and consciousness must be interpreted in light of the measured body temperature. Medical treatment should be adapted to the clinical presentation. External rewarming can be a safe and effective measure in neonatal patients.

Bradycardia in Accidental Severe Hypothermia in a Newborn: Treat or Don’t Touch? A case report

BackgroundHypothermia significantly affects mortality and morbidity of newborns. Literature about severe accidental hypothermia in neonates is limited. We present a case of a neonate suffering from severe accidental hypothermia. An understanding of the physiology of neonatal thermoregulation and hypothermia is important to decide on treatment.Case presentationWe report a case of severe accidental hypothermia (rectal temperature 25.7°C) in a hypothropic newborn due to prolonged exposure to low ambient temperature. The newborn presented bradycardic, bradypneic, lethargic, pale and cold. Bradycardia, bradypnea and consciousness were interpreted in the context of the measured body temperature. Therefore, no reanimation or intubation was initiated. The newborn was closely monitored and successfully treated only with active and passive rewarming. ConclusionClinical parameters such as heart frequency, blood pressure, respiration and consciousness must be interpreted in light of the measured body temperature. Medical treatment should be adapted to the clinical presentation. External rewarming can be a safe and effective measure in neonatal patients.

Prehospital interventions to prevent hypothermia in trauma patients: a scoping review

Objective: The aim of this review is to map the prehospital rewarming measures used to prevent hypothermia among trauma victims. Background: Hypothermia is responsible for an increase of the mortality and morbidity in trauma victims and its recognition and early treatment are crucial for the victim’s haemodynamic stabilisation. Prehospital interventions are particularly important, especially those that target bleeding control, haemodynamic stability, and safe body temperature. Registered nurses may be pivotal to prevention and minimisation of the dangerous effects of hypothermia. Study design and methods: A scoping review was used to identify articles from several online databases from 2010 to 2018. Studies in English, Spanish, and Portuguese were included. Two reviewers performed data extractions independently. Results: Seven studies were considered eligible for this review: two quantitative research studies, one qualitative research study, and four literature reviews. Rewarming measures can be divided into two main groups: passive rewarming, which includes the use of blankets, positioning the response unit to act as a windbreak, removing the patients’ wet clothes, drying the patient’s body, and increasing the ambient temperature; and active rewarming which includes the use of heating pads, heated oxygen, warmed intravenous fluids, peritoneal irrigation, arteriovenous rewarming, and haemodialysis. Discussion: Active measures reported by the included studies were always used as a complement to the passive measures. Active rewarming produced an increase in core temperature, and passive rewarming was responsible for intrinsic heat-generating mechanisms that will counteract heat loss. Patients receiving passive warming in addition to active warming measures presented a statistically significant increase in body core temperature as well as an improvement in the discomfort caused by cold. Conclusion: Rewarming measures seem to be essential for the prevention of hypothermia and to minimise the discomfort felt by the patient. In many countries registered nurses can play important roles in the prehospital context of trauma victim’s assistance. Greater understanding of these roles is necessary to the development of better practices.

Bradycardia in elderly patient: look at the body temperature

ABSTRACT We describe a case of a 83-year-old man who presented to the Emergency Department for bradycardia and reduced level of consciousness. His conditions had progressively worsened in the last few days and bradycardia induced his relatives to call on emergency team. He presented with hypoxia, cough, bradycardia and a reduced Glasgow Coma Scale value. The body temperature was not detected by standard thermometer and the electrocardiogram showed sinus bradycardia with prominent Osborne wave in the lateral precordial leads. His rectal temperature was 30.1 °C and the diagnostic work up showed a right lung pneumonia. He underwent active and passive rewarming treatment and sepsis treatment. Electrocardiographic abnormalities disappeared after rewarming and the patient was admitted to sub-intensive care unit.

A Guideline-Based Policy to Decrease Intensive Care Unit Admission Rates for Accidental Hypothermia

Rationale: Despite guidelines advising passive rewarming for mild accidental hypothermia (AH), patients are frequently admitted to intensive care unit (ICU) for active rewarming using a forced-air warming device. We implemented a new policy at our institution aimed at safely reducing ICU admissions for AH. We analyzed our practice pre- and post-policy intervention and compared our experiences with acute care hospitals in Connecticut. Methods: A retrospective chart review was performed on 203 participants with AH identified by primary and secondary discharge codes. Our new policy recommended passive rewarming on the medical floors for mild hypothermia (>32°C) and ICU admission for moderate hypothermia (<32°C). Practices of other Connecticut hospitals were obtained by surveying ICU nurse managers and medical directors. Results: Over a 3-year period, prior to rewarming policy change, 64% (n = 92) of patients with AH were admitted to ICU, with a mean ICU length of stay (LOS [SD]) of 2.75 (2.2) days. After the policy change, over a 3-year period, 15% (n = 9) were admitted to ICU ( P < .001), with an ICU LOS of 2.11 (0.9) days ( P = 0.005). In both groups with AH, altered mental status, infection, and acute alcohol intoxication were the most common diagnoses at presentation. Alcohol intoxication was more prevalent in the post-policy intervention group, pre 17% versus post 46% ( P < .001). No complications such as dermal burns or cardiac arrhythmias were noted with forced-air warming device use during either time period. Among the 29 hospitals surveyed, 20 used active rewarming in ICU or intermediate care units and 9 cared for patients on telemetry units. Most hospitals used active external rewarming for core body temperature of <35°C; however, 37% of hospitals performed active rewarming at temperatures >35°Cor lacked a policy. Conclusions: Reserving forced-air warming devices for the treatment of moderate-to-severe hypothermia (<32°C) significantly reduced ICU admissions for AH.

Passive rewarming from torpor in hibernating bats: minimizing metabolic costs and cardiac demands

Endothermic arousal from torpor is an energetically costly process and imposes enormous demands on the cardiovascular system, particularly during early stage arousal from low body temperature (Tb). To minimize these costs many bats and other heterothermic endotherms rewarm passively from torpor using solar radiation or fluctuating ambient temperature (Ta). Because the heart plays a critical role in the arousal process in terms of blood distribution and as a source of heat production, it is desirable to understand how the function of this organ responds to passive rewarming and how this relates to changes in metabolism and Tb. We investigated heart rate (HR) in hibernating long-eared bats ( Nyctophilus gouldi) and its relationship to oxygen consumption (V̇o2) and subcutaneous temperature (Tsub) during exposure to increasing Ta compared with endogenous arousals at constant low Ta. During passive rewarming, HR and V̇o2 remained low over a large Tsub range and increased concurrently with increasing Ta (Q10 2.4 and 2.5, respectively). Absolute values were higher than during steady-state torpor but below those measured during torpor entry. During active arousals, mean HR and V̇o2 were substantially higher than during passive rewarming at corresponding Tsub. In addition, partial passive rewarming reduced the cost of arousal from torpor by 53% compared with entirely active arousal. Our data show that passive rewarming considerably reduces arousal costs and arousal time; we suggest this may also contribute to minimizing exposure to oxidative stresses as well as demands on the cardiovascular system.

Characteristics of tree hollows used by Australian birds and bats

Many hundreds of species of wildlife worldwide are dependent on tree hollows (cavities) for their survival. I reviewed the published literature for hollow-using Australian birds and microbats to document their tree-hollow requirements and to guide future research and management. Such information is vital to the conservation of these species. The hollow requirements of only 35 of 114 hollow-using bird species and 15 of 42 hollow-using microbat species were documented in some detail. This overall paucity of information limits the ability to manage for the future requirements of species. However, some generalisations can guide management until further studies are conducted. Most species used a variety of available tree species, and the extensive use of dead trees probably reflects the high likelihood of these trees containing hollows. Birds (other than large parrots) and bats chose hollow entrances of a size close to body width. Large parrots require large hollows, with a preference for large vertical spouts and trunk hollows. Few birds or bats demonstrated an absolute requirement for high (>10 m) tree hollows, with most (70%) using some hollows with entrances ≤5 m above ground. Temperature has been postulated to influence roost selection among microbats because it enables passive rewarming from torpor and there is some evidence from Australian bats to support this. Many studies suggest a future shortage of hollow-bearing trees. Currently, artificial hollows appear to be the most likely interim solution to address this. Knowledge of the natural hollow requirements of species can be used to refine artificial-hollow designs. An increase in research effort is needed to address the many gaps in knowledge that currently exist. Priorities for research include (1) many additional studies to document the characteristics of the hollow-bearing trees used by species of microbat, (2) the need to conduct long-term bioregional studies of hollow-bearing tree attrition to help identify where management responses are most needed and (3) investigating whether fire plays a significant role in the creation of tree hollows of a range of size classes and therefore may have a management use. Such information has broad relevance because it will provide ecological insight that can be applied to the management of hollow-using birds and bats elsewhere in the world.

Fueling shivering thermogenesis during passive hypothermic recovery

In humans, the relative importance of oxidative fuels for sustaining shivering during passive hypothermic recovery or rewarming is still unclear. The main goals of this study were 1) to quantify the respective contributions of lipids and carbohydrates (CHO) during passive rewarming and 2) to determine the effects of precooling exercise on the pattern of fuel utilization. With indirect calorimetry methodologies, changes in fuel metabolism were quantified in nonacclimatized adult men shivering to rewarm from moderate hypothermia (core temperature ∼34.5°C) not following (Con) or following a precooling exercise at 75% V̇o2max for 15 min (Pre-CE). As hypothermic individuals shiver to normothermia, results showed that CHO dominate at all shivering intensities above 50% Shivpeak, while lipids were preferred at lower intensities. This change in the relative importance of CHO and lipids to total heat production was dictated entirely by modulating CHO oxidation rate, which decreased by as much as 10-fold from the beginning to the end of rewarming (from 1,611 ± 396 to 141 ± 361 mg/min for Con and 1,555 ± 230 to 207 ± 261 mg/min for Pre-CE). In contrast, lipid oxidation rate remained constant and low (relatively to maximal rates at exercise) throughout rewarming, averaging 183 ± 141 for Con and 207 ± 118 mg lipids/min for Pre-CE. In addition, this pattern of fuel selection remained the same between treatments. We concluded that fuel selection is regulated entirely by changes in CHO oxidation rate. Further research should focus on establishing the exact regulatory processes involved in achieving this large upregulation of CHO utilization rate following hypothermia.

Influence of skeletal muscle glycogen on passive rewarming after hypothermia

To examine the influence of muscle glycogen on the thermal responses to passive rewarming subsequent to mild hypothermia, eight subjects completed two cold-water immersions (18 degrees C), followed by 75 min of passive rewarming (24 degrees C air, resting in blanket). The experiments followed several days of different exercise-diet regimens eliciting either low (LMG; 141.0 +/- 10.5 mmol.kg.dry wt-1) or normal (NMG; 526.2 +/- 44.2 mmol.kg.dry wt-1) prewarming muscle glycogen levels. Cold-water immersion was performed for 180 min or to a rectal temperature (Tre) of 35.5 degrees C. In four subjects (group A, body fat = 20 +/- 1%), postimmersion Tre was similar to preimmersion Tre for both trials (36.73 +/- 0.18 vs. 37.26 +/- 0.18 degrees C, respectively). Passive rewarming in group A resulted in an increase in Tre of only 0.13 +/- 0.08 degrees C. Conversely, initial rewarming Tre for the other four subjects (group B, body fat = 12 +/- 1%) averaged 35.50 +/- 0.05 degrees C for both trials. Rewarming increased Tre similarly in group B during both LMG (0.76 +/- 0.25 degrees C) and NMG (0.89 +/- 0.13 degrees C). Afterdrop responses, evident only in those individuals whose body core cooled during immersion (group B), were not different between LMG and NMG. These data support the contention that Tre responses during passive rewarming are related to body insulation. Furthermore these results indicate that low muscle glycogen levels do not impair rewarming time nor alter after-drop responses during passive rewarming after mild-to-moderate hypothermia.