Objectives: To study the effects of fiberoptic bronchoscopy (FOB) at an altitude of 2250 m on arterial blood gases (ABG) and cardiac rhythm abnormality.
Methods: Fifty consecutive patients undergoing fiberoptic bronchoscopy were evaluated for the arterial blood gases and cardiac rhythm changes at Shimla (a moderate altitude of 2250 m), where there is a state of ambient hypoxia.
Results: The changes were noted in five stages ranging from the levels before the procedure till 15 minutes after the completion of the procedure. The mean fall in PaO2 levels in this study was 8 +/- 2.45 mm Hg and the fall was maximum at the end of procedure. Both smokers and nonsmokers showed a significant fall but the fall was more severe in smokers. The mean fall in SaO2 in this study was 3%. The increase in heart rate and blood pressure during FOB was significant as compared to baseline levels. There was no significant change in PH, PaCO2, HCO3. The commonest rhythm abnormality noted was sinus tachycardia which was well tolerated. No major cardiac arrhythmia was noted. It was further seen that the duration of the procedure and type of special procedure undertaken did not effect the levels significantly. Cyanosis was the commonest complication encountered (36%) and was seen more frequently in smokers and those with age more than 40 years. It was observed during the induction of bronchoscope and also during the further negotiation of the bronchoscope into the smaller branches of bronchial tree.
Conclusion: The changes in ABG and cardiac rhythm are comparable to the studies at sea level except the increased incidence of cyanosis.