In Reply:—
Dr. Beilin does not consider the use of phenylephrine infusions to be justified given the “minor” consequences of hypotension during spinal anesthesia for cesarean delivery. We disagree. One should not underestimate the importance of hypotension and its prevention. Dr. Beilin contends that serious adverse effects from hypotension are “almost nonexistent.” However, history warns us that major complications can indeed occur when hypotension is inadequately managed.1Dr. Beilin cited several articles2–4to support his contention, but careful reading of these reveals somewhat different messages. Macarthur2reported that “several reviews of maternal anesthetic deaths identified inadequately treated maternal hypotension as the major source of spinal anesthesia's morbidity and mortality.” Desalu and Kushimo3attributed low Apgar scores in some neonates in their study to relatively long durations of hypotension and stated that hypotension should be avoided in pregnant patients. Juhani and Hannele4emphasized the high incidence of minor complications and recommended that “hypotensive periods should be prevented.” Surprisingly, Dr. Beilin suggests that hypotension is not associated with neonatal acidosis or low Apgar scores. Datta et al. 5showed just such an association more than 20 yr ago. More recently, concern has been expressed that spinal anesthesia depresses fetal pH and base excess.6We believe the most important cause of this is hypotension and the way that it is treated.7
Dr. Beilin trivializes the seriousness of nausea and vomiting. Nausea and vomiting can cause significant distress to the patient and can interfere with surgery.8We regard its prevention as an important clinical indicator of quality of care. Examination of closed claims has emphasized the prominence of “minor” injuries including emotional distress in obstetric anesthesia cases,9and thus, there may also be medicolegal implications. Pulmonary aspiration has occurred;9that's pretty dangerous.
Dr. Beilin describes treatment of hypotension as “straightforward.” The large volume of research dedicated to this subject argues otherwise. There remain major controversies over the choice, dose, timing, and methods of administration of vasopressors and fluids. Dr. Beilin implies that it is sufficient to wait for hypotension to occur and then treat it with small boluses of ephedrine. It was the inadequacy of this very approach that several years ago stimulated us to direct research toward finding a better way.10
We make no excuses for our aggressive approach to the prevention of hypotension. Our work indicates that this provides the best outcomes for mother and baby.11Although, as stated in our article, we do advocate some caution with phenylephrine infusions because of the potential for blood pressure to transiently increase above baseline, we disagree that use of direct intraarterial blood pressure monitoring is necessary when using this technique in healthy patients. From our experience11–15of many years of using infusions of α agonists in many hundreds of patients, we have found measurement of noninvasive blood pressure every minute until delivery together with continuous monitoring of heart rate to be quite sufficient and, contrary to Dr. Beilin's opinion, quite practical. We have not found small transient increases in blood pressure and relative slowing of maternal heart rate to be harmful. Arguably, this is a safer physiologic state than profound vasodilation with marked tachycardia, the likely alternative. Furthermore, in clinical practice, with continuous heart rate monitoring and the freedom to titrate the phenylephrine infusion without the strict constraints of a study protocol, hypertension is less of a problem.
No treatment is perfect. But make not the mistake of underestimating the disease.
*The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China. warwick@cuhk.edu.hk
