Are We Afraid of General Anesthesia for Cesarean Section?

Are we afraid of general anesthesia for cesarean section? I remember when I was in school, I learned from the lecture that there are 3 reasons for avoiding GA besides decreased patient’s satisfaction and sleepy baby with GA. They are (1) difficult airway management (2) increased risk for aspiration (3) increased risk for uterine atony. I remember the thoughts of putting the mom to sleep was scary when I was on the OB rotation because we were taught that it was more likely to run into difficult airway situations. During my whole month of OB rotation, I had one case that truly required general anesthesia.  We all know that the parturients are considered full stomach and induction of RSI with CP is the same as for other non-OB patients with full stomach. For the uterine atony, we have different types of drugs to improve uterine atony.  The point of  my story is that in reality, our biggest concern is to encounter a difficult airway.

Is our concern legitimate?  Well, all the retrospective reviews were conducted back in the 80’s. For instance, back in 1980, there was 3 million deliveries in the country and C/S rate was about 16.5%. Most of the c-section cases were emergent and urgent cases, and fewer were elective cases compared to today. In addition, some of the non-anesthesia trained providers such as ED physician were involved in providing anesthesia. Furthermore, the airway devices available back then were limited to Mac/Miller and fiber bronchoscope. Hence, the number of difficult airway encountered was significantly higher than today.

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It is evident that ….difficult/failed intubation accounts for the majority of maternal deaths associated with anesthesia and regional anesthesia rarely causes deaths.

There is ….only one certain way of avoiding complications during anesthesia and that is the substitution of regional anesthesia.

Moir D, et al Obstetric Anesthesia and Analgesia 1986

As we can see, after 1980, it is ingrained in the community that it is likely to run into difficult airway situation in obstetric population and hence spinal/epidural is a safer choice for the mother and baby. ACOG also recommended regional anesthesia for c-section when possible. However, regional anesthesia is not without risk itself.Based on insurance claims from 1990-2003, general anesthesia for c-section had 28 cased that caused maternal death/brain damage whereas regional anesthesia had 41 cases. In the 41 cases of regional cases, 80% of cases were due to high neuraxial block and there was a delay in recognizing and/or treating sequelae of the high block.

High regional block – the failed intubation of the new millennium?
As deaths from failed intubation decline, a new emerges: high spinal.
Anesthesiology. 1992 Jul;77(1):67-73.

Relative risk analysis of factors associated with difficult intubation in obstetric anesthesia.

In this study listed above, 1500 cases were general anesthesia for c/s. All intubation performed by anesthesia residents and failed intubation was 1:750. And subsequent intubation was performed successfully by attending anesthesiologists. There was no failed intubation even with Mallampati IV. Among the 76 Mallampati IV patients, 5 were considered difficult. With our modern airway adjuncts such as glide, Macgrath, the complication associated with difficult airway is actually very low.  For example, grade 3/4 view with regular blade is converted to grade I/II with glide. In addition, LMA has also been proven to be useful in OB difficult airway management. Furthermore, monitoring is much more advanced compared to 1980’s. Pulse oximetry wasn’t readily available in every OR back in the 1980’s.

In summary, difficult airway is not necessarily increased in parturients particularly with the help of new airway adjuncts. We shouldn’t be afraid of ghost that belonged in the past! images

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