|Year : 2021 | Volume
| Issue : 1 | Page : 24-28
Cold injuries in the glacial regions of India
Priya Ranjan, Aditya Pawar, Anant Kumar Naik, Saurabh Bhardwaj, Pawan Sharma
Department of Surgery, Army Field Hospital, Pratppur, Leh & Ladakh, India
|Date of Submission||25-May-2020|
|Date of Decision||21-Jun-2020|
|Date of Acceptance||24-Sep-2020|
|Date of Web Publication||22-Jun-2021|
Maj (Dr). Aditya Pawar
Department of Surgery, Field Hospital, Pratappur, Leh, Ladakh - 194 401, Leh & Ladakh
Source of Support: None, Conflict of Interest: None
Background: Personnel deployed at an altitude ranging from 9000 ft to 23,000 ft are exposed to sub-zero temperatures up to −40°C. These conditions lead to the development of various cold injuries which presents in varying grades and severity. Aim: The aim of this study is to study the epidemiological trends and assess risk factors/conditions those are contributing to the development of cold weather injuries (CWI) at extreme cold climate in high altitude areas. Methodology: This is a retrospective, observational study on cold injury cases evacuated from the northern glaciers of India. The data were collected and tabulated in MS-Excel sheets, and analysis was done using percentage, mean, median, linear regression, and P value calculation. SPSS statistical analysis software version 23 was employed for generating the results. P < 0.05 was considered for statistically significant. Results: The annual incidence of cold injuries calculated for troops deployed at high altitude (>9000 feet) with extreme cold climate is 6.4/1000/year. The average duration of exposure for the development of CWI was found to be 4.85 h with a standard deviation = 2.88 h. Statistically significant association was found between the median temperatures and number of cold injury cases evacuated monthly with a strong negative coefficient of correlation (Pearson's) value r = −0.8214, and P = 0.001063. No correlation was found between the severity of frostbites and duration of exposure as the coefficient of correlation r (Pearson's) was weakly positive with a value of 0.19 and statistically not significant with P = 0.127. Conclusion: This study highlights the magnitude of problem, high risk zones, and predisposing activities. Statistical association has been drawn between altitude, temperature and duration of exposure with burden of cold injury. This study provides an insight with respect to associations and risk factors for the development of CWI, in Indian perspective and may be beneficial for better planning and preventive measures to reduce burden of CWI.
Keywords: Cold injuries, frostbites, high altitude
|How to cite this article:|
Ranjan P, Pawar A, Naik AK, Bhardwaj S, Sharma P. Cold injuries in the glacial regions of India. J Mar Med Soc 2021;23:24-8
| Introduction|| |
This is an original study performed at a peripheral field hospital, located at 10,000 ft. This forward medical echelon caters for casualties evacuated from extreme cold climate in high altitude area and adjoining areas of responsibility, thus providing us with a unique opportunity to study and manage cold weather injuries (CWI).
Once believed to be condition peculiar only to military personnel and wars, it has over a period of time involved civilian population engaging in various outdoor activities primarily mountaineering. Although it is true that the maximum information of cold injuries does come from accounts of war and many medical terminology of present use were coined by military doctors managing them. The earliest records of mass cold injuries comes from the accounts of Xenophon, a young Athenian officer whose army sustained heavy tolls from cold inclement weather while retreating from Armenia in the winters of 401–400 BC. Hannibal similarly suffered massive losses during his invasion in North Italy, when they marched across the Alps into the valley of Po, in 218 BC. Barron Larrey, Surgeon in Chief of Napoleon's army who made very important observations during his experiences in Russian Invasion, in the winters of 1812–1813. It was he who proposed that the repeated re-warming and re-freezing cycles have a deleterious outcome on the survival of tissue.
Thus, it is an extremely important condition for surgeons working in peripheral hospitals. The personnel deployed at an altitude ranging from 9000 ft to 23,000 ft are exposed to sub-zero temperatures up to −40°C. These conditions lead to he development of various cold injuries which presents in varying grades and severity. Thus, the importance of studying the epidemiological pattern cannot be emphasized more as it will help in understanding the various risk factors/conditions and trends that may contribute in the development of CWI.
| Methodology|| |
This is a retrospective, observational study conducted at peripheral field hospital located at an altitude of 10,000 ft. The study group included all the defence personnel evacuated as cases of cold injuries, from this region, which is part of the northern glaciers of India. Patients were evacuated from the various altitudes ranging from 9,000ft to 23000ft and were exposed to extreme cold climatic conditions ranging from −39°C to +15°C. The effective temperatures were even lower considering the strong wind chill factors that are prevalent in this terrain. Cold injury data were collected from the cold injury register, admission and discharge register, and clinical case sheets being maintained at our hospital. A total of 64 cases were studied, who were evacuated between June 2018 and May 2019. All cases that were initially referred as cold injury cases but were eventually given a different diagnosis after being evaluated by the author were excluded from the study. The cold injury cases were divided into various grades as per the clinical classification. They were classified into Chilblains and Frostbites. Frost bites were further subdivided into four grades of severity, i.e., Grade I to Grade IV [Table 1], in increasing order of severity. However, in a certain cases where we encountered dubious presentation and clinical dilemma, we categorized such cases as borderline Grade III and borderline Grade IV. Three sectors with high burden of cases have been designated with alphabets “X” “A” and “B,” due to confidentiality reasons.
The data were tabulated in MS-Excel sheets and analysis was done using mean, median, percentage, linear regression and P value calculation. SPSS statistical analysis software version 23 (IBM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp.) was employed for generating the results. P < 0.05 was considered statistically significant.
| Results|| |
In our study, the overall annual incidence of CWI calculated for personnel deployed at extreme cold climate in high altitude area and adjoining area of responsibility was calculated to be 6.4/1000/year. Incidence from sectors which were main contributors to cases of CWI, Sector X, A and B, was noted to be 15.15/1000/year.
The age group of our cohort ranged from 20 years to 43 years old. We noted that majority of individuals were <30 –year old. It was assessed that 75% (n = 48) patients were <30-year-old, 17% (n = 11) patients were in the age group of 30–39 years, whereas only 8% (n = 5) cases were reported to be more than 40 years old. The average age was calculated to be 27.14 years, and the median age was found to be 25 years.
The relation of number of casualties evacuated with the altitude was studied, and we noticed an increase in the number of cold injury cases with respect to altitude. Of the total casualties, 48% (n = 31) patients were evacuated from the altitude above 15,000 ft, i.e., Stage III. Thirty-nine percent (n = 25) cases were evacuated from Stage II (>12,000–≤15,000 ft), and only 13% (n = 8) were evacuated from <12,000 ft i.e., Stage I [Table 2].
|Table 2: Table depicting number of cold weather injuries cases with respect to altitude|
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We recorded the minimum, maximum, and median temperatures for all months and co-related these temperatures with number of casualties being evacuated each month. We found a strong negative correlation with Pearson's value r = −0.8214 i.e., higher number of cold injuries were recorded in month of minimum median temperature. This data is statistically significant with and P = 0.001063.
It was brought out in our study that the most common reason for developing cold injuries was when individuals participated in long duration treks. Majority, 52% of cases were affected from cold injuries during such treks/link movements. Twenty-four percent of casualties were contributed each from post activities and training activities [Figure 1].
The mean duration of exposure which leads to development of cold injury was calculated to be 4.85 h (n = 38) with a standard deviation (SD) = 2.88 h. However, no correlation was found between the severity of frostbites and duration of exposure as the coefficient of correlation r (Pearson's) was weakly positive with a value of 0.19 and statistically not significant with P = 0.127.
We recorded a total of 64 cases of cold injuries of which 53 (83%) cases were of frost bite, 7 (11%) cases were diagnosed with chilblains and only 4 (6%) cases of frost nip were recorded.
Of the 53 cases of frostbites recorded we further assessed the composition of injuries in various grades of severity namely Grades I, II, III and IV, as per the clinical guidelines [Table 1]. However in cases with clinical dilemma we classified certain cases as “borderline” where overlapping of clinical features and suspicious presentation were encountered. We noted 31 cases of Grade II and less severity. A total of 19 cases were recorded in borderline Grade-III and Grade-III category. Only two cases for borderline Grade-IV and Grade-IV, each were recorded [Figure 2].
It has been brought out in our study that 59%(n = 38) patients of cold injuries had involvement of hands. Thirty three percent (n = 21) patients had feet involvement and only 8% (n = 5) cases had facial involvement. There were no cases of both upper and lower limb involvement [Figure 3].
Of all the cold injuries involving extremities, 71% (n = 42) cases had only one extremity involved and 29% (n = 17) cases had more than one extremity involved.
It was also noted that of all the extremity involvement 58% (n = 34) cases had more than one digits involved and 42% (n = 8) cases had only one digit involved.
Our analysis also reiterates the fact that winter months (December, January and February) contributed to the bulk of casualties with 87% cases being evacuated during these 3 months. This corroborated well with the data on months with peak minimum and lowest median temperatures [Figure 4] and [Table 3].
|Table 3: Monthly temperature variations across the year with corresponding Cold weather injuries burden|
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|Figure 4: Distribution of cold injury cases with respect to seasonal variation|
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We also noted that only two individuals out of 64 (3.12%) cases were smokers. No individual had any previous history of cold injuries
| Discussion|| |
In our study, we calculated the annual Incidence for personnel exposed to extreme cold climate at high altitude area of Northern glaciers of India, to be 6.4/1000/year. The annual Incidence rates calculated for hostile sectors namely X, A and B came out to be 15.15/1000/year. This data fares well as compared to 10 year study on the epidemiology of CWI in British Antarctic Survey personnel from 1986 to 1995, which showed an incidence rate of 65.6/1000/year. Another study done on Finnish men entering military service between July 1995 and January 1996 was done which noted an annual occurrence 2.2%.
We have been able to document a strong association between sub zero temperatures and the number of cold injury cases. We have calculated a strong negative Pearson's coefficient of co-relation r = −0.8214, signifying lower temperatures with higher number of cold injury. These results were statistically significant with a P = 0.001063. It may not be a novel finding but we have not come across similar data in our review of literature and hence it is worth highlighting.
The average age for personnel being affected by cold injuries in high altitudes and glacier was calculated to be 27.14 years, with a median age of 25 years. This data corroborates with the study published on mountaineering population by Harirchi et al., which revealed a mean age of 29.4 years However theses figures can be misleading as our sample size is not standardised with respect to age, with higher number of younger troops (<30yrs) as compared to other age groups.
It was also observed that the burden of CWI increased with increased in altitude. We recorded the maximum cases (48%) of cold injuries being evacuated from altitudes >15,000 ft. However, in the study done by Harirchi et al., they detected maximum cold injury cases from the altitude 9186–12,992 ft. This result is possibly due maximum expedition to peaks ranging in this altitude as discussed in their study.
The area in our study has high altitude and glaciers. It has been divided into many sectors, some of which are considered extremely hostile and inhabitable due to accessibility, wind chill factors, altitudes and other reasons and there are other sectors which are relatively better. The hostile sectors contributed to majority of cold injury cases i.e., 78%. Sector A and B are in general considered to be extremely hostile and inhabitable whereas the location X is a relatively better location, but still the high number of cold injuries contributed can be explained by the 3 weeks long tough survival course which each personnel has to undergo before being deployed in extreme cold conditions at high altitude area.
It has been clearly brought out in our study that 52% cases of cold injuries have happened while participating in long duration treks/link movement either during induction/de-induction process. Thus, this should be considered as a definite risk factor as it leads to long duration of exposure to inclement weather conditions. Long duration of trekking in snow logged paths leads to fatigability, dehydration and sweating. Also while on link movements, people are exposed to high wind chill factors as there are often no temporary shelters between two camps. The mean duration of exposure for development of cold injury was calculated to be 4.85 h with a SD = 2.88 h. However, no correlation was found between the severity of frostbites and duration of exposure as the coefficient of correlation r (Pearson's) was weakly positive with a value of 0.19 and statistically not significant with P = 0.127.
The most common cold injury recorded in our study is frostbite, contributing to 83% (n = 53) cases. Chilblains was noted in 11% of cases while frost nip in 7% of cases. This corroborates with the study done by Cattermole on the epidemiology of CWI in British Antarctic Survey personnel from 1986 to 1995 in which he recorded 95% of injuries were due to frostbite, 3% were hypothermia and 2% trench foot.
We noted 24% cases with Grade-I, [Picture 1] 33% Grade-II, 35% Grade-III (including both borderline and definite cases) and 8% cases of Grade-IV [Picture 2] frostbite injuries. The diagnosis for grade of injury has been made clinically by the author for all cases as he was the treating surgeon for all the cases recorded using clinical guidelines as per [Table 1], hence subjective variation can be considered negligible. Our data revealed a higher number of deeper injuries as compared to other studies, like the study by Harirchi et al. noted 83% of cases with grade-I injury. However, study done by Hota and Singh on 236 patients evacuated from similar terrain revealed 25.59% of Grade-I, 49.76% of Grade-II, 22.27% of Grade-III and 2.36% of Grade-IV frostbite cases. Similarly study done by Hashmi et al. on cases evacuated from Karokaram Ranges in Pakistan has revealed up to 92% cases with Grade-II and above injuries.
We also noted that the 59% (n = 38) cases had involvement of hands and 33% (n = 21) cases had foot involvement with only 8% (n = 5) cases with facial injuries. Of these 71% (n = 42) cases had only one extremity involved while rest 29% (n = 17) cases had more than one extremity involved. It was noted that individuals with only one extremity involved, 60% had only one digit involved while rest 40% cases had multiple digits involved. In Alaska (1990–95) frostbites occurred in the head region in 39.1% of the cases, in hands in 27.9% of the cases, and in the feet in 24.9% of the cases. While a study done in US military suggested that the most common site for frostbite were feet followed by hands and lastly face.
Our analysis also reiterates the fact that winter months (December, January and February) contributed to the bulk of casualties with 87% cases from these 3 months. This corroborated well with the data on months with peak minimum and lowest median temperatures.
| Conclusion|| |
This study has generated results by drawing statistically relevant correlation between cold injury cases, altitude and temperature. We were able to establish a strong negative co-relation (r = −0.8214) between temperature and burden of cold injury cases. These results were statistically significant with and P = 0.001063. This study also showed that with an increase in altitude the number of CWI cases also increased. The mean duration of exposure for development of cold injuries has been evaluated to be 4.85 h in susceptible individuals. This data is our interesting finding and also has significant implication in planning of moves and establishment of intermediate shelters between two distanced locations. However no significant association was established between duration of exposure with severity of CWI which suggests that the effect of various confounding factors like genetic predisposition, individual susceptibility, effective temperatures, direct/indirect and contact with snow/metal and others, will have to be considered to establish a logical co-relation between severity and duration of exposure, which is presently beyond the scope of this study. We noted that a large number of casualties are being reported from location X, at an altitude of 12,000 ft. Such high numbers of frostbite cases at this altitude, could be attributed to tough and relentless survival training imparted to these personnel. A detailed review of the practices and curriculum with timely breaks in between can possibly help in reducing the number of casualties. Casualties from difficult Sectors A and B have primarily happened during long trek movement of personnel while induction/de-induction process in the winter months of December, January and February. These induction and de-induction movements are done by negotiating treacherous terrains which are even more difficult when fresh snow is encountered in the winter months. These conditions leads to longer duration of treks causing dehydration, sweating and fatigue which are known risk factors for CWI.,
Necessary review and amendments in the planning of movements, preventive measures in the form of modern protective gears like electrically heated gloves/mittens and taking in account risk factors of altitude, temperature, and activities as brought out in this study can go a long way in reducing the casualty load of CWI. Also more studies to assess and objectively define the role of genetic predisposition, individual susceptibility, effective and ambient temperatures, hydration and nutritional status, fatigue, direct and indirect contact with snow/metal needs to be evaluated in more controlled studies. This will prevent disablement of trained man power due to weather and will also lead to decrease in financial burden incurred in evacuation, management and rehabilitation.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3]