title: Risk factors in high altitude pulmonary oedema.
abstract: OBJECTIVE
  To identify the risk factors for high altitude pulmonary oedema.
  
  
  METHODS
  A case control study.
  
  
  METHODS
  The study was conducted in the Department of Medicine, Military Hospital, Rawalpindi during October 1998 to October 2000.
  
  
  METHODS
  One hundred serving army personnel between 20 to 50 years of age were divided in two groups. First group comprised of 50 patients who developed high altitude pulmonary oedema at 4000 meters height and above. Second group consisted of 50 control subjects who accompanied the patients. Detailed history was obtained regarding height of native dwelling, rate of ascent, amount of exertion and preceding respiratory tract infection. The findings of both the groups were compared and statistically analyzed by application of Pearson's chi-square test. Difference was considered significant when p-value was < 0.05.
  
  
  RESULTS
  All the subjects were male. Average age of the indexed group was 29.4(+/- 4) years as compared to 27(+/- 5) years in the control group. Six patients (12%) were highland dwellers whereas 44 patients (88%) were inhabitants of lower heights. Average rate of ascent from 4000 meters to 4500 meters of the indexed group was 5(+/- 2) days while in control group it was 10(+/- 3) days. Twenty cases (40%) had history of severe exertion whereas such history was not present in any of the control group subjects. Only 2 patients had signs and symptoms of preceding respiratory tract infection.
  
  
  CONCLUSIONS
  Rapid rate of ascent, extreme physical exertion, low height of native dwelling and preceding respiratory tract infection are important risk factors for the development of high altitude pulmonary oedema. Proper acclimatization with gradual ascent plays important role in preventing this potentially fatal condition.
authors.affiliation: Department of Medicine, Combined Military Hospital, Badin Cantt, Sindh, Pakistan.
authors.forename: Haroon
authors.initials: H
authors.lastname: Rashid
authors.forename: Shoaib Naiyar
authors.initials: SN
authors.lastname: Hashmi
authors.forename: Tassawar
authors.initials: T
authors.lastname: Hussain
mesh_terms: D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000453:epidemiology*; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D011654:Pulmonary Edema / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors