The Role of an Ingestible Telemetric Thermometer in Preventing Exertional Heat Stroke, for a Patient with Healed Massive Burns Running the 2007 London Marathon
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JBUR-3302; No. of Pages 7 burns xxx (2010) xxx–xxx available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/burns Case report The role of an ingestible telemetric thermometer in preventing exertional heat stroke, for a patient with healed massive burns running the 2007 London marathon Ryckie G. Wade a, Peter Dziewulski b, Bruce M. Philp b,* a University of East Anglia, Norwich, United Kingdom b St. Andrew’s Centre, Broomfield Hospital, Chelmsford, United Kingdom article info external fixator. He required multiple surgical procedures to heal his burn wounds including free flap reconstruction of his Article history: forehead, and later free flap nasal reconstruction. He was Accepted 12 May 2010 discharged from hospital after 150 days. As a previous Ironman triathlete, the patient was deter- mined to return to competitive sports and began training for the London marathon 2007, 12 months after his initial injuries. 1. Introduction He was fitted with an Otto Bock Hydraulic Knee and O˝ ssur Flex-Foot to run. In addition, he used a lightweight below- Adequate thermoregulation relies upon an intact dermis and elbow prosthesis with a body powered split-hook terminal epidermis [1,2]. Cutaneous vessels dilate to dissipate heat device. However, the inability to sweat in burn injured and (‘‘dry heat loss’’ via conduction, convection and radiation) and grafted areas meant that he required a method of monitoring constrict in order to retain heat. Dermal sweat glands are vital his core temperature whilst exercising, in order to take adnexal structures required for heat loss during exercise via appropriate action to avoid hyperthermia. To monitor core evaporation (‘‘wet heat loss’’). It is generally believed that temperature, the CorTempTM ingestible telemetric sensor by extensive thermal damage to the integumentary system HQ Inc. was purchased at a cost of £1314.76 (Fig. 1). impairs thermoregulation for a variety of reasons. In 2007, the patient completed the London marathon in 7 h and 14 min (Fig. 2). The ingestible telemetric thermometer was ingested 4 h prior to exercise to ensure adequate readings 2. Case history thereafter and to remove interference from intake of foods or liquids. The device took serial recordings of his core In April 2004, a 38-year-old civil engineer injured in a road temperature (8C) and time elapsed. A PolarTM S625 sports  traffic accident, sustained 75% full thickness flame burns to watch was used to record heart rate (beats/min; bpm). A his face, scalp, left chest and back, and circumference burns of GarminTM ForerunnerTM personal GPS device was used to his left arm and both legs. His injuries were complicated by record speed. This data was transmitted to and recorded on an smoke inhalation and a fracture of the left femoral shaft. external device which he carried. He was also able to tag and The patient underwent immediate total burn excision, categorise the data by pace as either ‘‘Run’’, ‘‘Walk’’ or ‘‘Rest’’ trans-radial/ulnar amputation of the left forearm and a left and usually employed the order or running, then walking and disarticulation knee amputation and full body escharotomy then resting if his core temperature did not normalise whilst and fasciotomy. The left femoral fracture was treated with an walking. The data presented in Tables 1 and 2 were analysed * Corresponding author at: Department of Plastic reconstructive and Burns Surgery, St. Andrew’s Centre, Broomfield Hospital, CM1 7ET Chelmsford, United Kingdom. Tel.: +44 1245 516122. E-mail addresses: [email protected] (R.G. Wade), [email protected] (P. Dziewulski), [email protected] (B.M. Philp). 0305-4179/$36.00 # 2010 Published by Elsevier Ltd and ISBI. doi:10.1016/j.burns.2010.05.012 Please cite this article in press as: Wade RG, et al. The role of an ingestible telemetric thermometer in preventing exertional heat stroke, for a patient with healed massive burns running the 2007 London marathon. Burns (2010), doi:10.1016/j.burns.2010.05.012 JBUR-3302; No. of Pages 7 2 burns xxx (2010) xxx–xxx with SPSS v17.0 (Chicago, IL) for means, standard deviations (SD), Pearson’s correlation coefficients and compared with two-tailed paired-samples t-tests. One-way ANOVA was performed with Bonferroni correction to compare resting, walking and running core temperature and average heart rate. Significance was set at the 5% level. The patient’s start core temperature (at 0 min) was 37.39 8C. His mean core temperature for the marathon was 39.18 8C (+1.79 8C); mean running core temperature was 39.26 8C (+1.87 8C) and walking was 39.16 8C (+1.77 8C). The patient took six rest periods when his core temperature reached 39.5 8C – this allowed him to cool by a mean of 0.39 8C over a mean of 11 min and 7 s, per rest. The patient completed the marathon with a core temperature of 39.70 8C (+2.31 8C from baseline), which took over 3 h to return to baseline. There was a statistically significant positive correlation between marathon time elapsed and core temperature (r = 0.295, p = 0.049). As he ran, there was a positive correlation between time and core temperature (r = 0.288, p = 0.233). When the patient slowed to a walk, there was a negative correlation between core temperature and time (r = 0.023, À p = 0.929). Furthermore, when the patient stopped to rest, there was a negative correlation between core temperature and time (r = 0.273, p = 0.29). À During the marathon, the patient’s mean HR was 163 bpm (SD = 13). His mean heart rate when running was 172 bpm, when walking was 162 bpm and when resting was 144 bpm. Interestingly, there was a negative correlation between marathon time elapsed and average heart rate (r = 0.170, À p = 0.265), which became statistically significant when we controlled for ‘‘running’’ (r = 0.675, p = 0.001) and ‘‘walking’’ À (r = 0.588, p = 0.13) paces. However, as expected there was a À positive correlation between heart rate and time spent ‘‘resting’’ (r = 0.464, p = 0.354). There was no statistically significant difference between core temperature when resting and walking ( p = 0.301), resting and running ( p = 0.242) or walking and running ( p = 0.239) with paired t-tests. ANOVA demonstrated no significant difference between the pace (walking, running or resting) and core temperature ( p = 0.329) or heart rate ( p = 0.210). 3. Discussion Previous studies have shown that persons with healed massive burns (>40% TBSA) have a reduced ability to dissipate heat, especially during exercise [3,4]. Although other areas of normal skin may sweat excessively, heat is produced faster than it can be dispelled and core temperature rises [3–7]. Skin temperature is inversely proportional to core temperate tolerance, however, little is known about the alterations in the thermoregulatory physiology of persons with healed massive burns. During a marathon, skin temperature is directly related to Fig. 1 – The CorTempTM ingestible telemetric thermometer external conditions including ambient temperature, humidity as compared to a standard mercury thermometer (top), the and air motion [8,9]. Conversely, core temperature is essen- external recording device with example pills in relative tially independent of environmental conditions [10] and size (middle) and a cross section of the pill showing the mostly dependent on metabolic rate [11]. Metabolic rate is inner components (bottom). proportional to the amount of energy expended and the specific heat of 1 kg of healthy body tissue which approx- Please cite this article in press as: Wade RG, et al. The role of an ingestible telemetric thermometer in preventing exertional heat stroke, for a patient with healed massive burns running the 2007 London marathon. Burns (2010), doi:10.1016/j.burns.2010.05.012 JBUR-3302; No. of Pages 7 burns xxx (2010) xxx–xxx 3 Fig. 2 – The patient crossing the finishing line with his teammate, of the London Team Triathlon 2007. imates to 3.5 kJ/8C/kg. During a typical marathon, heat subconsciously regulate their pace according to afferent production in a healthy adult rises exponentially and without feedback from tissues and the environment, in order to dissipation, core temperature would reach fatal levels within optimise muscle/skin blood flow, normalise their core 5 km/10 min [12]. It is unknown whether such physiological temperature and enhance performance [21]. We therefore parameters are mirrored in patients with healed burns or how hypothesise that patients with impaired thermoregualtion metabolic rate varies. Our patient usually ran for 5–10 min who wish to exercise maximally may safely do so in an inverse before having to stop/slow, which suggests that his ability to manner, by continuously monitoring their core temperature dissipate heat was significantly impaired. Further research and thereafter, consciously regulating their pace to avoid into exercise capacity is needed and how capacity relates to hyperthermia. TBSA. Marathon runners with healthy skin architecture com- Sweating is the most efficient means of heat loss (by monly finish a race with core temperatures of 38.5–39.5 8C, but evaporation) and largely unaffected by other physiological can have (rectal) core temperatures in excess of 40 8C [15,22– parameters. Vasodilatation is the inadequate alternative (by 24]. Recent trials on Ironman Triatheles found that (rectal) core convection), although maintenance of a blood pressure is a temperatures increased by only 1 8C from baseline [25] as quintessential prerequisite [13,14] and thus, vasodilatation is compared to novice athletes whose core temperatures only possible in well hydrated individuals, with normal skin frequently exceeded 40 8C [24]. Duffield et al. [19] reported architecture.