Summary of papers describing case series and experimental cooling models
| Author, date, and country | Patient group and interventions | Study type | Outcomes | Key results | Comments |
|---|---|---|---|---|---|
| BCU, Body cooling unit; Tre, rectal temperature; Tty, tympanic temperature; Tc, core temperature. | |||||
| Wyndham et al,20 1959, South Africa | 6 healthy volunteers exercised until Tre 40°C, cooled by immersion or evaporation | Within subject crossover trial | Cooling time to Tre 38.3°C, cooling rate (fall in Tc) over 60 min | Fastest mean cooling time 50 min, rate 0.07°C/min, with evaporative cooling | Small numbers. Applicable to heat stroke patients? |
| Weiner & Khogali,21 1980, UK | 6 healthy volunteers exercised until Tty 39.5°C, then cooled by immersion in 15°C water, cold air spray or warm air spray (BCU) | Within subject crossover trial | Reduction in Tty of 2.0°C (to 37.5°C) | Cooling time 6.5 min (rate 0.31°C/min) with BCU, 18.4 min (rate 0.11°C/min) with immersion | Small numbers. Methodology not explained in detail. Tympanic measurement used. Applicable to heat stroke patients? |
| Kielblock et al,22 1986, South Africa | 5 healthy volunteers exercised until Tre reached 2°C above baseline, then subjected to different methods of cooling (see results) | Within subject crossover trial | Reduction in Tre of 2.0°C (to baseline) | Mean cooling time 73.6 min (cold packs), 59.8 min (evaporative cooling); p<0.01. Combined: 53.6 min or 0.04°C/min (no difference) | Small numbers. Methodology not explained in detail. Applicable to heat stroke patients? |
| Clapp et al,23 2001, USA | 5 healthy volunteers exercised until Tre 38.8°C, then subjected to different methods of cooling (see results) | Within subject crossover trial | Cooling rate (fall in Tc) over 30 min | Mean cooling rates 0.25°C/min (torso immersion), 0.16°C/min (hand and feet immersion) and 0.11°C/min (fan) | Small numbers. Not compared with standard of care. Low target temperature. Applicable to heat stroke patients? |
| Mitchell et al,24 2001, USA | 10 healthy volunteers exercised to preset limits, then cooled using 4 methods (see results) | Within subject crossover trial | Cooling rate (fall in Tc) during two 12 min cooling periods | Mean cooling rates 0.02–0.05°C/min, no difference between passive cooling and fan or spray assisted cooling | Study not designed to look at heatstroke model. Inadequate temperature rise and cooling times to assess treatments |
| Khogali & Weiner,13 1980, Kuwait | 18 heatstroke patients cooled in a BCU | Case series | Cooling time to Tre<38°C. Mortality | Cooling times ranged from 30 to 300 min. 2 patients died. Calculated mean cooling rate 0.05°C/min | Data on cooling rates not given |
| Hart et al,14 1982, USA | 28 classical heatstroke patients. All cooled by iced water immersion or ice massage if immersion not possible | Case series | Cooling time to Tre<102°F (38.89°C) | 26 out of 28 cooled within 30 min, all within 45 min | Different intervention (immersion v massage) not defined in study group. No numerical data given. Study designed to primarily look at other parameters |
| Vicario et al,6 1986, USA | 39 heatstroke patients, cooled by various means depending on physician preference | Case series | Temperature reduction over first hour, mortality | 69% cooled to T<38.9°C within 60 min. Mortality 21%, lower when cooled faster | Case series looking at prognosis depending on cooling times, rather than comparing methods |
| Graham et al,15 1986, USA | 14 classical heatstroke patients, cooled by evaporative methods. Ice also used around torso | Case series | Cooling time to Tre<39.4°C, mortality | Cooling times ranged from 34 to 89 min, median 60 min. 1 patient died | Cooling methods not well defined: mixed methods. Cooling rates not calculable |
| Al-Aska et al,16 1987, Saudi Arabia | 25 classical heatstroke patients cooled with simplified cooling bed | Case series | Cooling time to Tre<39°C | Mean cooling time 40 min (rate 0.09°C/min) with simplified cooling bed | Methods not well described: brief letter |
| Poulton & Walker,17 1987, USA | 3 heatstroke patients (2 exertional, 1 classical), cooled by helicopter downdraft | Case series | Cooling time to T<38.5°C | Mean cooling time 24 min, rate 0.10°C/min | Methods not adequately described. Only mean data given |
| Costrini,18 1990, USA | 27 patients with exertional heat illness, all cooled by iced water immersion | Case series | Cooling time to Tre<39°C, mortality | Mean cooling time 19.2 min or rate 0.15°C/min. No deaths | Methods not adequately described. Only mean data given |
| Horowitz,19 1989, USA | Heatstroke patient cooled by iced peritoneal lavage | Case report | Cooling rate. No end point given | Cooling rate 0.11°C/min during lavage cycle. Patient survived | Case report. Evaporative cooling also used |