Pulmonary arterial pressure in conscious and anaesthetized dogs

In 84 conscious mongrel dogs weighting 19.0 +/- 3.2 kg (x +/- s), the mean pressure in the pulmonary artery was found to be 14.2 +/- 3.1 mmHg. In 102 anaesthetized dogs weighting 19.9 +/- 3.2 kg, pulmonary arterial pressure was 14.3 +/- 2.8 mmHg and pressure in the abdominal aorta 121.3 +/- 16.9 mmHg ; the O2 saturation in the arterial blood recorded oximetrically at the same time was 91.9 +/- 1.3%. Statistical analysis of the data derived from a selection of 87 of these anaesthetized dogs (body=weight : 15-25 kg ; Sao2 : 90-94 % ; mean aortic pressure : 80-150 mmHg ; mean pulmonary arterial pressure : 9-19.5 mmHg) revealed a significant relation between pulmonary pressure and O2 saturation. No significant relation was demonstrable, however, between these pressures and the animals' body-weight. The lower limit of the normal range of mean pulmonary pressure was 8 mmHg and the upper limit 20 mmHg.