Canadian Journal of Anesthesia, Vol 28, 550-555, Copyright © 1981 by Canadian Anesthesiologists' Society

Single Versus Multiple Pulmonary Emboli: Different Haemodynamic and Blood Gas Results

¹ Department of Anaesthesia, University of Toronto, St. Michael's Hospital, 30 Bond Street, Toronto, Ontario, M5B 1W8

Address Correspondence and reprint requests to: Dr. W.H. Noble, Dept of Anaesthesia, St. Michael's Hospital, 30 Bond Street, Toronto, Ontario M5B 1W8

We evaluated haemodynamic and blood gas changes following the intravenous infusion of starch microemboli (63-74µ). Comparisons were made between dogs receiving a single embolus and dogs receiving an equal quantity of embolus divided into small doses given at 30 minute intervals (multiple emboli). The most significant finding was that the same quantity of embolus produces different effects. In the dogs receiving a single embolus of 150 mg·kg^-1 of starch, Pa_o2 fell from 11.3 to 7.6 kPa (85 to 57 torr)(p < 0.025) and Q^·_s/Q^·_t increased from 11 to 34 per cent (p < 0.01). In the multiple emboli dogs, after a total dose of 150 mg·kg^-1 of starch, there was a small but not significant fall in Pa_o2 from 11.6 to 10.8 kPa (87 to 81 torr), and Q^·_s/Q^·_t did not change significantly. In the single embolus dogs Q^· increased significantly after an embolus of 100 mg·kg^-1 of starch (p < 0.05). After a single embolus of 150 mg·kg^-1, Q^· was variable; 3 dogs showed a decrease, and 2 an increase, however the mean change was not significant. In the multiple emboli dogs, Q^· decreased significantly (p < 0.005).

Key Words: EMBOLISM, pulmonary, haemodynamic effects, blood gas effects