Caesarean section is the surgical delivery of the foetus. There seems to be quite a variety in the incidence of this approach for delivery.
Foetal compromise e.g.
Umbilical cord prolapse
Maternal compromise e.g.
Failure to progress
High risk for vaginal delivery
High risk uterine scar
These indications are divided into 4 categories based on the urgency of the situation:
Emergency - Immediate threat to life of mother or foetus
Urgent - Maternal or foetal compromise that isn’t immediately life threatening
Scheduled - No compromise but early delivery is needed
Emergency - Category 1 Indications may induced: prolonged foetal bradycardia, uterine rupture, umbilical cord prolapse. The delivery of the foetus should be done as soon as possible. A target time of ‘decision to delivery’ is put at 30 minutes. In many of these cases a general anaesthetic is the anaesthetic choice due to the increased speed. However, as with many things in medicine this category remains a spectrum and each case will provide a variety of factors that impact on the risk vs benefit decisions.
Urgent - Category 2 In general, these patients need fairly rapid intervention but there is more time to achieve this safely. There is less clear guidance on the ‘decision to delivery’ time here, but a figure of 75 minutes is frequently used. There is usually time to provide regional anaesthesia in these case.
Category 3 & 4 These deliveries are both on a relatively planned basis and the timing of the C-section should reflect this to optimise the provision of safe care.
The usual surgical approach is via a lower segment incision. This has the advantages of:
Better cosmetic appearance
Reduced intraoperative complications e.g. bleeding
Reduced pain post op
A vaginal birth is possible in future pregnancies
Other incisions may be required depending on certain obstetric or surgical factors e.g. transverse lie of foetus, placental position. In many of these case, future attempts at vaginal delivery are advised against due to the increased risk of uterine rupture. The incisions applied to the skin and uterus need not necessarily be in the same plane. Previous abdominal surgery may make the surgical process more complicated and time consuming.
The steps are:
Skin incision (as above)
Sharp dissection of subcutaneous tissue down to rectus sheath
Transverse incision of rectus sheath with scalpel and then extended
Facial sheath separated from rectus muscle
Vertical division of the rectus muscles
Opening of the parietal peritoneum
Separation of the utero-vesical peritoneum to allow access to the lower segment of the uterus
Transverse incision of the outer layers of the uterus, followed by blunt (finger) dissection down to avoid foetal injury
Delivery of the baby - fundal pressure is needed
Oxytocin 5 units is administered by the anaesthetist after delivery to aid placental contraction
Delivery of the placenta by cord traction
Suturing of uterine incision
Cleaning of paracolic gutters with swab
Closure of the rectus sheath
Closure of skin (+ subcutaneous tissue if a lot of it)
In some cases where delivery is difficult, extension of the incision into the upper part of the uterus may be needed. This may be either a ‘J’ incision or and ‘inverted-T’ incision.
Some parts of the procedure are more stimulating than others and worth warning the patient about during regional anaesthesia:
Rectus sheath stretching
Cleaning of paracolic gutters
If the uterus needs to be exteriorised (sometimes needed for repair) then this can be very uncomfortable.
Urinary tract injury
Bleeding is a common feature of C-section, but usually within the realms of the anticipatory physiological changes of pregnancy (an average of 500ml). Other visceral damage is rare, but an increased risk if there has been previous abdominal surgery due to the adhesional changes. Routine bladder catheterisation is an important preoperative step to reduce the size of the bladder and reduce the risk of injury.
There are several options for provision of anaesthesia for C-section:
Combined spinal epidural
The approach will be guided by a number of factors including; urgency, maternal preference, maternal/obstetric comorbidity.
In general, neuraxial anaesthesia is the method of choice. It has several significant advantages over general anaesthesia here:
Improved maternal safety - the risk of aspiration and ventilatory difficulty is higher
Reduced neonatal sedation
Presence at the time of delivery (maternal and paternal)
Better post op analgesia and mobilisation
Contraindications apply to regional techniques e.g. coagulopathy, CVS instability
Time (although spinal anaesthesia can often be performed very quickly)
The balance of these advantages and disadvantages means that the vast majority of C-sections are performed under a regional technique, and this approach is generally promoted. Careful assessment still needs to be applied to see if there are factors that may alter the risk vs benefit balance for each patient.
Links & References
Birnbach, D. Browne, I. Anaesthesia for obstetric, in: Miller’s Anaesthesia (7th ed).
Allman, K. Wilson, I (eds). Oxford handbook of anaesthesia (3rd ed). 2012. Oxford University Press
Heazell, A. Clift, J (eds). Obstetrics for anaesthetists. 2008. Cambridge University Press.
Levy, D. Anaesthesia for caesarean section. BJA CEPD reviews. 2001. 1(6):171-176
McGlennan, A. Mustafa, A. General anaesthesia for caesarean section. CEACCP. 2009. 9(5): 148-151.