Weather and chinook winds in relation to spontaneous pneumothoraces.

Background: Spontaneous pneumothorax (SP) results from the rupture of blebs or emphysematous bullae. Rapid changes in weather may precipitate this process. The city of Calgary is well suited to examine the effects of weather and specifically the rapid changes in weather associated with a chinook event and the occurrence of SP.

Methods: We performed a retrospective chart review of all cases of SP in the Calgary Health Region from 2001 to 2005. We obtained local hourly weather data over the same period from Environment Canada. We then compared the rates of SP on chinook and nonchinook days. Further, we compared mean daily temperature, humidity, wind speed and atmospheric pressure on chinook and nonchinook days.

Results: In all, 220 SP events from 149 patients occurred during the 4.5-year study period. There was no significant difference in the rate of SP on chinook days versus nonchinook days (p = 0.80). Similarly, there was no significant difference in the rate of SP in each of the 4 seasons (p = 0.30). We observed significantly higher average wind speed and lower mean atmospheric pressure on days with SP versus days without (p = 0.009, p = 0.020, respectively). There was no difference in mean temperature or mean relative humidity when comparing days with SP versus days without.

Conclusion: We found no association between SP and chinook events. We observed significantly higher wind speeds and lower atmospheric pressures on days with SP versus days without.