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Three Part Question

In [patients with thermal burns, who haven't had immediate first aid cooling], does [delayed application of first aid cooling], [improve wound healing]?

Clinical Scenario

A 38 year old man was brought to our Emergency Department (ED), one and a half hours following flame burns to his forearms while working in woods. He hadn't had first aid cooling. Partial thickness burns were diagnosed. I wondered whether delayed application of first aid cooling, as part of his treatment in ED, would improve his wound healing.

Search Strategy

Medline and EMBASE using NHS Evidence Advanced Search
[exp burn*.ti] AND ["first aid".ti.ab OR "firstaid".ti.ab] AND [delay*.ti.ab OR duration.ti.ab] AND Limited to English language.

In addition reference lists were reviewed to identify additional papers not found in the computerised search.

Search Outcome

18 papers were found of which 14 were irrelevant. One was over 30 years old and had delayed the treatment only for 2 minutes. Could not find any trials done on human subjects.

The 3 remaining papers are shown in the table in chronological order.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Cuttle L et al August 2010 Australia	Porcine model with deep partial thickness burns (40 pigs with 2 burns on each)	Experimental animal study	Re-epithelialisation at 2 & 3 weeks post-burn.	After 2 weeks, the 3 hr delay tap water cooling re-epithelialised significantly faster compared to control (p=0.04) at 3 weeks.	Sample size is questionable, may be under powered. Didn't describe the allocation (randomisation & concealment) in to treatment subgroups and how large they were. One animal was euthanised during surgery & 4 wounds were excluded as being superficial. This could have affect the intension-to-treat analysis. People, who did weekly wound cleaning & dressing change, were not blinded to the firstaid treatment. This could have influenced the final outcome. Only the outcome measurers were blinded and doesn't confirm that they were not involved in earlier phases of treatment, to prevent bias on outcome measurements. Significance of effectiveness was discribed using p values only, whithout demonstrating the confidence intervals. No comments were found on wound infection.
			% & thickness of Organising granulation tissue (OGT/scar tissue) at 6 weeks.	1 & 3 hr delay treatments had less contracted wounds compared to control (p=0.03). No significant difference in average %OGT & thickness among various delays of firstaid. However, the distribution of %OGT was significantly different among treatments. Control wounds had consistently higher %OGT, while delayed firstaided wounds had a larger proportion with lower %OGT (p=0.04)
			Cosmetic appearance at 6 weeks.	No significant difference among various delays of treatment.
Rajan V. et al July 2009 Australia	Porcine model of partial thickness burns. (12 pigs with 4 wounds on each)	Experimental animal study	Core temperature	Didn't fall below 35degrees C throughout the cooling process.	Sample size is questionable, may be under powered. Delayed firstaid(FA)cooling was compared against immediate FA, rather than no FA. Followed up only for 9 days, which is rather too short.
			Mean burn surface area (BSA) at days 1 & 9	Mean BSA of all wounds improved between day 1 & 9. The decrease in BSA reached statistical significance in immediate & 60min delayed firstaided groups (p<0.05)
			Histologic assessment of burn depth at days 1 & 9	No significant difference in burn depth rating between immediate, 5min, 20min & 60min delayed firstaid groups (p>0.05). Change in burn depth between Day 1 to 9 in each treatment group showed no overall significant difference (p>0.05)
Venter T.H.J et al November 2007 South Africa	Porcine model with deep dermal burns (10 pigs with 4 wound on each)	Experimental animal study	Clinical & histological assessment of wounds for damage & subsequent healing at intervals upto 3 weeks	30min delayed cooling with tap water showed less wound damage almost similar to immediate cooling. Immediate cooling with ice water, caused more wound damage than 30min delayed ice water cooling.	Sample size is questionable, may be under powered. Clinical & histological wound assessors were not blinded for the treatments. Statistical significance of results were not demonstrated.

Comment(s)

Literature evidences that considerable proportion of patients with burns present to EDs without pre-hospital first aid cooling [4, 5]. Delayed cooling was not commented in a recently published review of first aid treatments for burns [6]. Therefore, it is a clinically valid question to rise whether delayed cooling of burns in ED is worthwhile. There are no human studies performed on this topic. Pig skin has shown to be a clinically relevant model for human skin & wound healing. Currently available evidences are based on experimental studies done on pigs, with variable quality. All of them points to the conclusion that delayed application of first aid cooling have beneficial effects on wound healing. Cooling with tap water has shown to be more effective than ice water (1-8 degrees C). In another porcine model study, tap water cooling for 20minutes has shown statistically significant improvement in burn depth, compared to non-cooling & 5min, 10min & 30min cooling durations [7]. A carefully designed human study, ideally a PRCT, on this topic is warranted. However, consideration of a control group without cooling would be an ethical dilemma.

Editor Comment

KMJ

Clinical Bottom Line

Cooling with running tap water for 20minutes is evidenced as the best first aid cooling method. It would be beneficial to cool burnt wounds, which are not pre-hospital cooled, in ED using running tap water for 20 minutes.

References

1. Cuttle L et al The optimal duration and delay of first aid treatment for deep partial thickness burn injuries Burns August 2010, vol./is. 36/5 (673-9)
2. Rajan V. et al Delayed cooling of an acute scald contact burn injury in a porcine model: Is it worthwhile? Journal of Burn Care & Research July 2009, vol./is. 30/4 (729-34)
3. Venter T.H.J et al Cooling of the burn wound:The ideal temperature of the coolant Burns November 2007, vol./is.33/7(917-22)
4. Rawlins JM, Khan AA, Shenton AF, Sharpe DT. Epidemiology and outcome analysis of 208 children with burns attending an emergency department. Paediatric Emergency Care 2007; 23(5): (289-293)
5. Chipp E, Walton J, Gorman DF, Moiemen NS. A 1 year study of burn injuries in a British Emergency Department. Burns 2008; 34(4): (516-520)
6. Cuttle L, Pearn J, McMillan JR, Kimble RM. A review of first aid treatments for burn injuries. Burns 2009; 35(6): (768-775)
7. Bartlett N, Yuan J, Holland AJ, Harvey JG et al. Optimal duration of cooling for an acute scald contact burn injury in a porcine model. Journal of Burn Care & Research 2008; 29(5): (828-834)