We commend Dr. Lofsky's recent review of 22 anesthesiology claims after maternal arrest "Doctors Company Reviews Maternal Arrests Cases," APSF Newsletter, 2007;22(2):28). However, we believe there were some very important omissions. In particular, failure to mention the critical importance for most parturients of cesarean delivery within 4-5 minutes of maternal cardiac arrest, when appropriately performed ACLS has failed to restore circulation. Dr. Lofsky presents data suggesting that the fetus may be more resistant to maternal hypoxia and hypotension than the mother and concludes that this "reaffirms the importance of the anesthesiologist's primary focus being the welfare of the mother." She further cautions, "This raises the question as to whether maternal resuscitation should ever be intentionally delayed in order to expedite delivery of the fetus." We are concerned that readers may take this to mean that immediate or early cesarean delivery would impede resuscitation and be harmful to the mother.
The best chance of fetal survival is maternal survival. While clinicians usually appreciate the fetal benefit from expeditious perimortem cesarean delivery, many are not aware that immediate delivery may also prove life-saving to the mother.1 Following delivery beneficial changes include immediate relief of aortocaval compression by the gravid uterus with consequent improved venous return and aortic output, improved pulmonary mechanics, and decreased oxygen demand. In 1968, Katz et al.2 first demonstrated the fetal benefit of perimortem cesarean delivery within 5 minutes of cardiac arrest. More recently, they performed a 20-year review of maternal cardiac arrests described in the literature and found that in 12 out of 18 cases in which hemodynamic status was reported, maternal pulse and blood pressure returned immediately after cesarean delivery and in no case was there deterioration of the maternal condition with the cesarean delivery.3 The American Heart Association's 2005 guidelines state that when maternal cardiac arrest is not immediately reversed by BLS and ACLS: "The resuscitation leader should consider the need for an emergency hysterotomy (cesarean delivery) protocol as soon as a pregnant woman develops cardiac arrest."4 They further emphasize
"The critical point to remember is that you will lose both mother and infant if you cannot restore blood flow to the mother's heart. Note that 4 to 5 minutes is the maximum time rescuers will have to determine if the arrest can be reversed by BLS and ACLS interventions. The rescue team is not required to wait for this time to elapse before initiating emergency hysterotomy."4
Only when uterine size corresponds to a gestational age less than 20 weeks is immediate delivery unlikely to benefit the mother. Between 20 and 23 weeks (before fetal viability), urgent cesarean delivery is likely to benefit only the mother; after 24 weeks it may benefit both mother and fetus. Even when delivery cannot be accomplished within 5 minutes, performing it as soon as is feasible usually will confer maternal benefit and may result in a healthy fetus.2 The underlying cause of the cardiac arrest and the severity and duration of maternal and fetal compromise prior to arrest will also impact outcome.
Thirteen of the 22 arrests in the current series occurred after institution of regional anesthetic block (unintentional subarachnoid block in 7 out of 8 labor epidural catheter placements and spinal anesthesia for cesarean delivery in 5 cases). Resuscitation can be extremely difficult in the presence of high spinal anesthesia. Respiratory depression rapidly ensues, while the extensive sympathectomy causes massive vasodilation and block of the cardio-accelerator nerves (T1 to T4), severely impairing venous return and cardiac output. Combined with aortocaval compression caused by the gravid uterus and the low cardiac output state achievable by CPR, there may be minimal or no venous return or cardiac output until delivery is accomplished.
Dr. Lofsky highlights the difficulties and delays associated with transporting patients in extremis to the operating room. Cesarean delivery within 4-5 minutes of cardiac arrest and starting resuscitation may require that it be performed in the patient's room, or wherever the arrest occurs. It is noteworthy that, in the only case in Dr. Lofsky's series where the mother survived without neurologic impairment, the anesthesiologist immediately ventilated the patient with an Ambu-bag and the obstetrician accomplished a crash cesarean delivery within minutes while still in the labor room. We realize that some obstetricians believe that perimortem cesarean delivery always merits transfer to the operating room, even when a parturient is in cardiac arrest.5 However, as Dr. Lofsky describes, transferring a patient undergoing ACLS is logistically challenging and time-consuming, will almost certainly result in interruption of chest compressions and monitoring, and overall will probably decrease maternal and fetal survival.2,3 To optimize maternal survival and the chance of good neurologic outcome, institutions and medical personnel should make advance preparations designed to facilitate urgent cesarean delivery in non-operating room locations in this circumstance. Of course, CPR and ACLS should be continued throughout delivery, wherever this occurs.
The 22 cases of maternal arrest reviewed in this series should be a reminder that ACLS and CPR for parturients must be better taught to practitioners at all levels. Critical ACLS modifications for pregnant patients include always maintaining left uterine displacement of at least 15-30 degrees; placing the rescuer's hands several cm higher on the sternum to obtain better cardiac output with compressions; and, most important, consideration for immediate cesarean delivery in a patient who has not responded after 4-5 minutes of ACLS.4 Familiarity with the most recent American Heart Association's recommendations for management of cardiac arrest associated with pregnancy4 should be mandatory for all medical or nursing personnel who potentially provide care to pregnant women.
I appreciate Drs. Carvalho and Cohen's discussion of the issues raised in my article. It does not seem to me that our views are mutually exclusive. My questioning a delay in maternal resuscitation to facilitate delivery was a response to the 7 cases in which mothers were transported out of their labor rooms prior to the institution of full BCLS and/or ACLS measures, although they were in arrest on arrival in the OR. Many of the nurses and anesthesia providers involved in those claims explained the urgency to transport as related to their concerns about a possibly dying fetus. Attention appeared to initially focus primarily on the non-reassuring fetal heart tones caused by maternal cardio-respiratory compromise, rather than on the mother's resuscitation.
I agree that we might need to reemphasize all alternatives for accomplishing cesarean section deliveries necessitated by maternal arrest (which is soon accompanied by fetal distress). With the design of many labor and delivery wards, it may simply be unreasonable to expect to get an unstable patient undergoing resuscitation onto the OR table within the 4 to 5 minute window described above. The one "near miss" case described in my article was unique both because the C-section was accomplished expeditiously in the labor room and because there was both immediate and uninterrupted resuscitation of the mother by the anesthesia provider.
Notably, 3 mothers in the series sustained brain damage even though their respiratory arrests occurred after the cesarean delivery of their babies. There were allegations in those cases that monitoring was inadequate and resuscitation provided too late. Timing appears to be critical and immediate resuscitation attempts imperative. I believe we are all in agreement that there should not be a delay in making an initial attempt to ventilate a mother and support her blood pressure for the sole reason of transporting her somewhere else. Within those first 4 to 5 minutes of maternal resuscitation, it is still A,B,C (Airway, Breathing, and Circulation) before D (Delivery).1