Hypoxia and myocardial ischaemia during peripheral angioplasty

We have used continuous ambulatory electrocardiography and concurrent monitoring of arterial oxygen saturation (SpO2) and non-invasive arterial pressure in a pilot study of 29 unsedated patients undergoing percutaneous peripheral vascular angioplasty. Twelve patients (Group 1) received oxygen 41 min-1 by Hudson mask during the procedure, the remaining 17 patients (Group 2) breathing air. Fourteen patients in Group 2 had an SpO2 of 94% or below during the procedure, compared with two patients in Group 1. Episodes of silent ischaemia were recorded during the procedure in one patient in Group 1 and five patients in Group 2. Administration of oxygen significantly reduced the incidence and severity of hypoxaemia, and may be responsible for the reduction in silent ischaemia.