Patra et al noted that emetic symptoms were reduced in patients who developed post-spinal hypotension after being given 100% oxygen, thus implicating hypoxaemia at the emetic centre as a probable causative factor. There were no significant changes between the two groups with respect to maternal pulse rate, respira tory rate and oxygen saturation. Ephedrine was used in this study as the vasopressor of choice because it was readily available and on the basis that it does not appre ciably affect uterine blood flow unlike the pure alpha adrenergic agonist phenylephrine which causes increase in uterine artery resistance and may reduce placental blood flow despite effective treatment of maternal hypotension