Core warming of a burn patient during excision to prevent hypothermia

An integrative literature review of factors contributing to hypothermia in adults during the emergent (ebb) phase of a severe burn injury

BACKGROUND

During the emergent (ebb) phase (first 72 h), the adult person with a severe burn experiences loss of body heat, decreased metabolism, and poor tissue perfusion putting them at risk of hypothermia, increased morbidity, and mortality. Therefore, timely and targeted care is imperative.

AIM

The aim of this integrative literature review was to develop a framework of the factors contributing to hypothermia in adults with a severe burn injury during the emergent (ebb) phase.

METHODS

An integrative review of research literature was undertaken as it provides an orderly process in the sourcing and evaluation of the literature. Only peer reviewed research articles, published in scholarly journals were selected for inclusion (n = 26). Research rigor and quality for each research article was determined using JBI Global appraisal tools relevant to the methodology of the selected study.

FINDINGS

Contributing factors were classified under three key themes: Individual, Pre-hospital, and In-hospital factors.

CONCLUSION

The structured approach enabled the development of an evidence-based framework identifying factors contributing to hypothermia in adults with a severe burn injury during the emergent (ebb) phase and adds knowledge to improve standardized care of the adult person with a severe burn injury.

Perioperative targeted temperature management of severely burned patients by means of an oesophageal temperature probe

BACKGROUND

Hypothermia in severely burned patients is associated with a significant increase in morbidity and mortality. The use of an oesophageal heat exchanger tube (EHT) can improve perioperative body temperatures in severely burned patients. The aim of this study was to investigate the intraoperative warming effect of oesophageal heat transfer in severe burn patients.

METHODS

Single-centre retrospective study performed at the Burns Centre of the University Hospital Zurich. Between January 2020 and May 2021 perioperative temperature management with EHT was explored in burned patients with a total body surface area (TBSA) larger than 30%. Data from patients, who received perioperative temperature management by EHT, were compared to data from the same patients during interventions performed under standard temperature management matching for length and type of intervention.

RESULTS

A total of 30 interventions (15 with and 15 without EHT) in 10 patients were analysed. Patient were 38 [26-48] years of age, presented with severe burns covering a median of 50 [42-64] % TBSA and were characterized by an ABSI of 10 [8-12] points. When receiving EHT management patients experienced warming at 0.07 °C per minute (4.2 °C/h) compared to a temperature loss of - 0.03 °C per minute (1.8 °C/h) when only receiving standard temperature management (p < 0.0001). No adverse or serious adverse events were reported.

CONCLUSION

The use of an oesophageal heat transfer device was effective and safe in providing perioperative warming to severely burned patients when compared to a standard temperature management protocol. By employing an EHT as primary temperature management device perioperative hypothermia in severely burned patients can possibly be averted, potentially leading to reduced hypothermia-associated complications.

Current understanding of thermo(dys)regulation in severe burn injury and the pathophysiological influence of hypermetabolism, adrenergic stress and hypothalamic regulation—a systematic review

Background

In this systematic review, we summarize the aetiology as well as the current knowledge regarding thermo(dys)regulation and hypothermia after severe burn trauma and aim to present key concepts of pathophysiology and treatment options. Severe burn injuries with >20% total body surface area (TBSA) affected commonly leave the patient requiring several surgical procedures, prolonged hospital stays and cause substantial changes to body composition and metabolism in the acute and long-term phase. Particularly in severely burned patients, the loss of intact skin and the dysregulation of peripheral and central thermoregulatory processes may lead to substantial complications.

Methods

A systematic and protocol-based search for suitable publications was conducted following the PRISMA guidelines. Articles were screened and included if deemed eligible. This encompasses animal-based in vivo studies as well as clinical studies examining the control-loops of thermoregulation and metabolic stability within burn patients

Results

Both experimental animal studies and clinical studies examining thermoregulation and metabolic functions within burn patients have produced a general understanding of core concepts which are, nonetheless, lacking in detail. We describe the wide range of pathophysiological alterations observed after severe burn trauma and highlight the association between thermoregulation and hypermetabolism as well as the interactions between nearly all organ systems. Lastly, the current clinical standards of mitigating the negative effects of thermodysregulation and hypothermia are summarized, as a comprehensive understanding and implementation of the key concepts is critical for patient survival and long-term well-being.

Conclusions

The available in vivo animal models have provided many insights into the interwoven pathophysiology of severe burn injury, especially concerning thermoregulation. We offer an outlook on concepts of altered central thermoregulation from non-burn research as potential areas of future research interest and aim to provide an overview of the clinical implications of temperature management in burn patients.

Factors contributing to the restoration of normothermia after hypothermia in people with a major burn injury in the first 24 h of hospital admission

BACKGROUND

People with burn injury experiencing hypothermia are at risk of serious complications such as shock, multisystem organ failure, and death. There is limited information available for health professionals with regard to factors that contribute to restoration of normothermia after hypothermia in people with a major burn injury.

OBJECTIVE

The aim of the study was to identify factors that contribute to normothermia restoration after hypothermia in people with 10% or more total body surface area (TBSA) burn in the first 24 h of admission to a burn care hospital.

METHODS

The study was guided by the Gearing Framework for retrospective chart audit. The sample comprised medical charts of all adult people (n = 113) with a burn injury more than 10% of their TBSA admitted to a single-site burn care hospital intensive care unit in Victoria, Australia, between May 31, 2013, and June 1, 2015. Descriptive statistics were used to describe the sample, and logistic regression was conducted to predict variables contributing to return to normothermia in people with burn injury. Charts with incomplete data were excluded.

FINDINGS

The sample (n = 50) recorded a median initial temperature on admission to the emergency department (ED) of 35.4°C (range = 31.9-37.2°C) and took on an average of 6.2 (standard deviation [SD] = 4.96) hours to return to normothermia (36.5°C). Women took around 6 h longer than men to return to normothermia (mean = 11.14 h, SD = 5.58; mean = 5.38 h, SD = 4.41). Positive correlations were noted between TBSA%, the length of time between admission to the ED and the intensive care unit, and the hours taken to reach normothermia. Regression analysis suggests the initial recorded temperature on admission to the ED was the main predictor of the time body temperature takes to return to normothermia (β = .513, p < .001).

CONCLUSION

This study provides information for practice changes by highlighting the need for guidelines and education programs for health professionals to ensure the delivery of optimum care to people with burn injury.

[Target Temperature Control in Patients with Burns]

Severe burns lead to a persistent hypermetabolic response of the organism with significantly increased resting energy turnover, multi-organ dysfunction, muscle breakdown and increased risk of infection. Elevated core and skin temperatures are characteristic. A further increase in the metabolic rate can be triggered by heat losses, for which these patients are particularly predisposed due to high heat dissipation via evaporation of moisture and impairment of the thermoregulatory and insulating properties of the burnt skin. This is especially true in all treatment situations with exposure to large, uncovered skin surfaces, such as primary care, dressing changes in the intensive care unit and surgery with extensive sterile operating field. It has been shown that hypothermia is associated with numerous risks for the burn patient. Consistent heat management with measurement of the core body temperature and application of external and internal heat protection measures is recommended. Traditionally, an increase in room temperature is used here. However, this effective measure is limited by the resilience of the intensive care practitioners and the surgeons. To avoid perioperative hypothermia, strict surgical planning with limitation of the duration of surgery and close intraoperative communication about the risk of hypothermia are of particular importance.The differentiation between accepted temperature increase and infectious fever is often only possible by the inclusion of further examination findings. The criterion for sepsis is a temperature above 39 °C or below 36.5 °C.

Glucose Metabolism in Burns-What Happens?

Severe burns represent an important challenge for patients and medical teams. They lead to profound metabolic alterations, trigger a systemic inflammatory response, crush the immune defense, impair the function of the heart, lungs, kidneys, liver, etc. The metabolism is shifted towards a hypermetabolic state, and this situation might persist for years after the burn, having deleterious consequences for the patient's health. Severely burned patients lack energy substrates and react in order to produce and maintain augmented levels of glucose, which is the fuel "ready to use" by cells. In this paper, we discuss biological substances that induce a hyperglycemic response, concur to insulin resistance, and determine cell disturbance after a severe burn. We also focus on the most effective agents that provide pharmacological modulations of the changes in glucose metabolism.

Effects of a hot ambient operating theatre on manual dexterity, psychological and physiological parameters in staff during a simulated burn surgery

OBJECTIVES

Hot environmental conditions can result in a high core-temperature and dehydration which can impair physical and cognitive performance. This study aimed to assess the effects of a hot operating theatre on various performance, physiological and psychological parameters in staff during a simulated burn surgery.

METHODS

Due to varying activity levels, surgery staff were allocated to either an Active (n = 9) or Less-Active (n = 8) subgroup, with both subgroups performing two simulated burn surgery trials (CONTROL: ambient conditions; 23±0.2°C, 35.8±1.2% RH and HOT: 34±0°C, 28.3±1.9% RH; 150 min duration for each trial), using a crossover design with four weeks between trials. Manual dexterity, core-temperature, heart-rate, sweat-loss, thermal sensation and alertness were assessed at various time points during surgery.

RESULTS

Pre-trials, 13/17 participants were mildly-significantly dehydrated (HOT) while 12/17 participants were mildly-significantly dehydrated (CONTROL). There were no significant differences in manual dexterity scores between trials, however there was a tendency for scores to be lower/impaired during HOT (both subgroups) compared to CONTROL, at various time-points (Cohen's d = -0.74 to -0.50). Furthermore, alertness scores tended to be higher/better in HOT (Active subgroup only) for most time-points (p = 0.06) compared to CONTROL, while core-temperature and heart-rate were higher in HOT either overall (Active; p<0.05) or at numerous time points (Less-Active; p<0.05). Finally, sweat-loss and thermal sensation were greater/higher in HOT for both subgroups (p<0.05).

CONCLUSIONS

A hot operating theatre resulted in significantly higher core-temperature, heart-rate, thermal sensation and sweat-loss in staff. There was also a tendency for slight impairment in manual dexterity, while alertness improved. A longer, real-life surgery is likely to further increase physiological variables assessed here and in turn affect optimal performance/outcomes.

User-Centred Healing-Oriented Conditions in the Design of Hospital Environments

Design approaches towards energy efficient hospitals often result in a deteriorated indoor environmental quality, adverse health and comfort outcomes, and is a public health concern. This research presents an advanced approach to the design of a hospital environment based on a stimulative paradigm of healing to achieve not only healthy but also comforting conditions. A hospital room for severely burn patient was considered as one of the most demanding spaces. The healing environment was designed as a multi-levelled, dynamic process including the characteristics of users, building and systems. The developed integral user-centred cyber-physical system (UCCPS) was tested in a test room and compared to the conventional system. The thermodynamic responses of burn patients, health care worker and visitor were simulated by using modified human body exergy models. In a healing environment, UCCPS enables optimal thermal balance, individually regulated according to the user specifics. For burn patient it creates optimal healing-oriented conditions with the lowest possible human body exergy consumption (hbExC), lower metabolic thermal exergy, lower sweat exhalation, evaporation, lower radiation and convection. For healthcare workers and visitors, thermally comfortable conditions are attained with minimal hbExC and neutral thermal load on their bodies. The information on this is an aid in integral hospital design, especially for future extensive renovations and environmental health actions.

Important Developments in Burn Care

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Explain the epidemiology of severe burn injury in the context of socioeconomic status, gender, age, and burn cause. 2. Describe challenges with burn depth evaluation and novel methods of adjunctive assessment. 3. Summarize the survival and functional outcomes of severe burn injury. 4. State strategies of fluid resuscitation, endpoints to guide fluid titration, and sequelae of overresuscitation. 5. Recognize preventative measures of sepsis. 6. Explain intraoperative strategies to improve patient outcomes, including hemostasis, restrictive transfusion, temperature regulation, skin substitutes, and Meek skin grafting. 7. Translate updates in the pathophysiology of hypertrophic scarring into novel methods of clinical management. 8. Discuss the potential role of free tissue transfer in primary and secondary burn reconstruction.

SUMMARY

Management of burn-injured patients is a challenging and unique field for plastic surgeons. Significant advances over the past decade have occurred in resuscitation, burn wound management, sepsis, and reconstruction that have improved outcomes and quality of life after thermal injury. However, as patients with larger burns are resuscitated, an increased risk of nosocomial infections, sepsis, compartment syndromes, and venous thromboembolic phenomena have required adjustments in care to maintain quality of life after injury. This article outlines a number of recent developments in burn care that illustrate the evolution of the field to assist plastic surgeons involved in burn care.

Use of an Esophageal Heat Exchanger to Maintain Core Temperature during Burn Excisions and to Attenuate Pyrexia on the Burns Intensive Care Unit

Introduction. Burns patients are vulnerable to hyperthermia due to sepsis and SIRS and to hypothermia due to heat loss during excision surgery. Both states are associated with increased morbidity and mortality. We describe the first use of a novel esophageal heat exchange device in combination with a heater/cooler unit to manage perioperative hypothermia and postoperative pyrexia. Material and Methods. The device was used in three patients with full thickness burns of 51%, 49%, and 45% body surface area to reduce perioperative hypothermia during surgeries of >6 h duration and subsequently to control hyperthermia in one of the patients who developed pyrexia of 40°C on the 22nd postoperative day due to E. coli/Candida septicaemia which was unresponsive to conventional cooling strategies. Results. Perioperative core temperature was maintained at 37°C for all three patients, and it was possible to reduce ambient temperature to 26°C to increase comfort levels for the operating team. The core temperature of the pyrexial patient was reduced to 38.5°C within 2.5 h of instituting the device and maintained around this value thereafter. Conclusion. The device was easy to use with no adverse incidents and helped maintain normothermia in all cases.

Maintenance of normothermia during burn surgery with an intravascular temperature control system: a non-randomised controlled trial

BACKGROUND

Hypothermia remains one of the major factors limiting surgery in extensively burned patients. We evaluated the effectiveness of an intravascular rewarming technique using CoolGard 3000™ system and Icy™ catheter to maintain normothermia during surgeries of severe burned patients and compared these findings to a historical control group.

METHODS

This was a controlled non-randomised trial conducted between March 2008 and August 2009. Patients with burns greater than or equal to 40% of the total body surface area were included. Before the first burn excision, the Icy™ catheter was placed in the inferior vena cava via the femoral vein. Warming was then initiated and maintained until the bladder temperature reached over 37.5°C. The bladder temperature was recorded every 30min during surgery and for the first hour post-operatively and compared to a historical control group.

RESULTS

We enrolled 4 patients and 11 surgeries in the CoolGard™ group and compared them to 3 patients and 10 surgeries in the historical cohort. All intraoperative bladder temperatures from T=30 were statistically different in the two groups. In the CoolGard™ group, no patient became hypothermic and no surgery was aborted because the patient's temperature had rapidly fallen below the threshold temperature (35.5°C). No device-related complication was reported.

CONCLUSION

The use of an intravenous warming catheter is a novel approach to maintain normothermia during surgery in burn victims and may be more effective than traditional methods.

Comparing ambient, air-convection, and fluid-convection heating techniques in treating hypothermic burn patients, a clinical RCT

Background

Hypothermia in burns is common and increases morbidity and mortality. Several methods are available to reach and maintain normal core body temperature, but have not yet been evaluated in critical care for burned patients. Our unit's ordinary technique for controlling body temperature (Bair Hugger^®+ radiator ceiling + bed warmer + Hotline^®) has many drawbacks e.g.; slow and the working environment is hampered.

The aim of this study was to compare our ordinary heating technique with newly-developed methods: the Allon™2001 Thermowrap (a temperature regulating water-mattress), and Warmcloud (a temperature regulating air-mattress).

Methods

Ten consecutive burned patients (> 20% total burned surface area and a core temperature < 36.0°C) were included in this prospective, randomised, comparative study. Patients were randomly exposed to 3 heating methods. Each treatment/measuring-cycle lasted for 6 hours. Each heating method was assessed for 2 hours according to a randomised timetable. Core temperature was measured using an indwelling (bladder) thermistor. Paired t-tests were used to assess the significance of differences between the treatments within the patients. ANOVA was used to assess the differences in temperature from the first to the last measurement among all treatments. Three-way ANOVA with the Tukey HSD post hoc test and a repeated measures ANOVA was used in the same manner, but included information about patients and treatment/measuring-cycles to control for potential confounding. Data are presented as mean (SD) and (range). Probabilities of less than 0.05 were accepted as significant.

Results

The mean increase, 1.4 (SD 0.6°C; range 0.6-2.6°C) in core temperature/treatment/measuring-cycle highly significantly favoured the Allon™2001 Thermowrap in contrast to the conventional method 0.2 (0.6)°C (range -1.2 to 1.5°C) and the Warmcloud 0.3 (0.4)°C (range -0.4 to 0.9°C). The procedures for using the Allon™2001 Thermowrap were experienced to be more comfortable and straightforward than the conventional method or the Warmcloud.

Conclusions

The Allon™2001 Thermowrap was more effective than the Warmcloud or the conventional method in controlling patients' temperatures.

Catheter related venous thrombosis with cooling and warming catheters: two case reports

INTRODUCTION

Intravascular cooling and warming catheters are among a range of proliferating technologies used for temperature control. Complications related to the use of these devices are few, and no definitive evidence has been presented thus far to indicate any differences in complication rates between these balloon catheters and other central vein catheters. We report two cases of cooling and warming catheter-related venous thrombosis. They are the both first ones report of this kind in the literature.

CASE PRESENTATION

The first case was a 17-year-old man admitted with severe head trauma. On day 6, he presented with severe intracranial hypertension, requiring increased medical treatment: mannitol osmotherapy, barbiturate-induced coma, and mild therapeutic hypothermia. A double-lumen Alsius CoolLine catheter was placed in the inferior veina cava via the left femoral vein and active cooling was begun. On day 10, physical examination of the left inguinal area and echo-doppler revealed catheter-related thrombophlebitis with left iliocaval vein occlusion. The second case was a 42-year-old man admitted with a severe burn. On day 2, the patient was taken to the operating room for the first staged excision of his burn wounds. A triple lumen Alsius Icy catheter was placed in the inferior vena cava via the right femoral vein and active core warming of the patient was begun. From day 2 to day 7, active core warming of the patient was maintained. On day 7, he presented with a septic thrombophlebitis. Echo-doppler revealed a 4-cm-long thrombus at the femoral catheter site with complete blood flow obstruction and blood cultures and catheter tip were positive for methicillin-resistant Staphylococcus aureus.

CONCLUSION

Although generally considered safe, cooling and warming catheters can be associated with mechanical complications such as catheter-related venous thrombosis. Intensivists who use these devices should be aware of this possible complication. Finally, as with any other invasive catheter, to reduce the risk of complications, the catheter should be removed promptly when no longer needed.

Catheter related venous thrombosis with cooling and warming catheters: two case reports

Introduction

Intravascular cooling and warming catheters are among a range of proliferating technologies used for temperature control. Complications related to the use of these devices are few, and no definitive evidence has been presented thus far to indicate any differences in complication rates between these balloon catheters and other central vein catheters. We report two cases of cooling and warming catheter-related venous thrombosis. They are the both first ones report of this kind in the literature.

Case presentation

The first case was a 17-year-old man admitted with severe head trauma. On day 6, he presented with severe intracranial hypertension, requiring increased medical treatment: mannitol osmotherapy, barbiturate-induced coma, and mild therapeutic hypothermia. A double-lumen Alsius CoolLine catheter was placed in the inferior veina cava via the left femoral vein and active cooling was begun. On day 10, physical examination of the left inguinal area and echo-doppler revealed catheter-related thrombophlebitis with left iliocaval vein occlusion. The second case was a 42-year-old man admitted with a severe burn. On day 2, the patient was taken to the operating room for the first staged excision of his burn wounds. A triple lumen Alsius Icy catheter was placed in the inferior vena cava via the right femoral vein and active core warming of the patient was begun. From day 2 to day 7, active core warming of the patient was maintained. On day 7, he presented with a septic thrombophlebitis. Echo-doppler revealed a 4-cm-long thrombus at the femoral catheter site with complete blood flow obstruction and blood cultures and catheter tip were positive for methicillin-resistant Staphylococcus aureus.

Conclusion

Although generally considered safe, cooling and warming catheters can be associated with mechanical complications such as catheter-related venous thrombosis. Intensivists who use these devices should be aware of this possible complication. Finally, as with any other invasive catheter, to reduce the risk of complications, the catheter should be removed promptly when no longer needed.

Hypothermia during burn surgery and postoperative acute lung injury in extensively burned patients

BACKGROUND

Respiratory dysfunction remains one of the major complications after burn surgery in extensively burned patients. We evaluated the relationship between the invasiveness of burn surgery and acute lung injury (ALI).

METHODS

Patients admitted to our burn unit between 2006 and 2007 with burns greater than or equal to 30% of the total body surface area without severe inhalation injury were entered into this study. Of sixteen patients (mean age, 49.4 +/- 19.3 years, total body surface area 46.0% +/- 14.9%) who underwent burn surgery (3-6 days postburn), vital signs, hemodynamic parameters, blood gas analysis, and peak inspiratory pressure were recorded. Lung injury severity (LIS) score was serially determined. Bronchoalveolar lavage (BAL) was performed before and 24 hour postoperatively.

RESULTS

Body temperature and LIS score preoperatively (baseline) were 37.1 degrees C +/- 0.9 degrees C and 3.8 degrees C +/- 2.2 degrees C, respectively. LIS score increased with increased polymorphonuclear neutrophil in BAL 24 hour postoperatively in 7 of 10 patients with intraoperative temperature decreasing more than 1 degrees C. Extent of excision (20.3% +/- 6.7%), transfusion (4.3 +/- 3.0 units), or duration of surgery (147 +/- 49 minutes) alone did not show significant correlation with the development of ALI postoperatively.

CONCLUSION

In patients with severe burn injury, hypothermia during surgery despite aggressive intraoperative warming is significantly correlated with the development of ALI with increased polymorphonuclear neutrophil in BAL and may reflect the severity of invasiveness.