Dr. Charles Collins,
Consultant Trainer in Anaesthesia, Health Services Partnership, Project International Nepal Fellowship, Nepal

Dr. Anek Gurung,
Specialist Anaesthetist, Western Regional Hospital, Pokhara, Nepal.

Potential Problems		General anaesthesia
Preoperative preparation		Intraoperative haemorrhage
Local anaesthesia		Special circumstances
Regional anaesthesia		Summary & References

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Caesarean section (LSCS) is one of the commonest operations performed in the developing world and is often carried out in difficult circumstances. As with any operation, the anaesthetist should first think about all the problems that may occur as it is always better to be prepared for trouble than to be taken by surprise.

The problems concern 5 areas:

1. The patients
2. The surgery (and the surgeon!)
3. The drugs (both anaesthetic drugs and any taken by the patient)
4. Equipment
5. The anaesthetist

1. Problems with the patients

Caesarean section is often said to be the unique situation where the anaesthetist has to deal with 2 patients under the same anaesthetic. The health of the baby has to be considered as well as that of the mother.

Risks to the mother. Changes in  maternal physiology are described elsewhere in this journal, as are problems associated with hypertensive disease of pregnancy. Any other significant concurrent disease, such as maternal diabetes or sickle cell disease, will have to be handled in the usual way. The important changes affecting anaesthesia are:

Pregnant women are at risk of hypoxia. They are more difficult to oxygenate than non-pregnant patients due to changes in their respiratory mechanics and they use the oxygen more quickly because of a higher metabolic rate. This situation can be made worse by other factors. Obesity makes control of the airway more difficult and interstitial fluid retention may make the larynx harder to visualise for successful intubation.

Although fluid retention is a feature of pregnancy, a more common problem is the risk of hypovolaemia either due to obstetric complications causing significant antepartum haemorrhage or, very commonly, prolonged labour leading to exhaustion and dehydration. This is particularly noticeable in the hot season.

The pregnant mother is at greater risk of pulmonary acid aspiration, as regurgitation of acidic stomach contents is more likely than in non-pregnant patients. This can lead to catastrophic aspiration pneumonitis.

The patient with hypertensive disease of pregnancy may have abnormal clotting function and multiple other complications of this disease.

Risks to the fetus include hypoxia and acidosis if placental blood flow is reduced. Since maternal blood pressure is maintained at the expense (if necessary) of placental perfusion, by the time a significant drop in maternal blood pressure has been measured the fetus has already suffered from reduced placental perfusion. The general condition of the fetus should be considered:

• What is the state of the fetus preoperatively?
• How significant is any "fetal distress"?
• Is there an obstetric complication, such as cord prolapse, that puts the fetus at imminent risk and requires the quickest possible intervention?
• Are there more than one fetus?

Risks to mother and fetus. Both need to be protected from the "supine hypotensive syndrome" (aorto-caval compression). This occurs when the maternal inferior vena cava and, to a lesser extent, the aorta are compressed by the gravid uterus if the mother is allowed to lie on her back.

2. Problems with the surgery

Ask yourself the following questions:

• Who is the surgeon, how experienced, how long does he expect to take and what incision is planned?
• Are blood and other intravenous fluids available?
• Is there a surgical complication such as placenta praevia that could cause serious intra-operative haemorrhage ?
• Does your surgeon lift the uterus right out of the abdominal cavity after delivery in order to suture it? (Under regional anaesthesia this is very uncomfortable and is rarely necessary.)

3. Problems with drugs

As with any patient, the pregnant woman may be taking drugs for concurrent diseases which have to be considered, e.g. steroids, anti diabetic medication. They may also be taking drugs that can react with anaesthetic drugs, e.g. antidepressant medication.

With all drugs, beware of the weight of the patient and try and weigh her if possible. Do not believe average doses quoted in textbooks but give drugs as mg/kg. This is particularly important in Asia where, in the authors' experience, fully grown women at term may only weigh 35 to 40kg.

There is a moderate reduction in psuedo-cholinesterase in pregnant women compared with the non-pregnant population (at least in Caucasians). This is more notable immediately post-partum. Although the initial dose of suxamethonium is the same, its effect may be prolonged. If suxamethonium has not been correctly stored it may not be fully effective.

Ketamine causes a rise in blood pressure. It should not be given to mothers with hypertension but is well worth considering if a mother is being resuscitated from hypovolaemia. Ergometrine, given to encourage uterine contraction immediately after delivery, frequently causes nausea and vomiting. It is better to use oxytocin in the awake patient having a regional or local anaesthetic.

• Are all general anaesthesia including emergency drugs available?

Drugs used for the anaesthetic may affect the fetus. Anaesthetic drugs cross the placenta and therefore a "deep" anaesthetic will sedate the baby and risk birth apnoea. Narcotics and sedatives should not be given to the mother prior to delivery. Gallamine crosses the placenta and will affect the fetus. Other neuromuscular blocking agents are safe.

4. Problems with equipment

• What anaesthetic equipment is available? Is there adequate oxygen , either in cylinders or as a functioning oxygen concentrator? Is the power supply reliable?
• Does the sucker work and is there a back up manually operated sucker?
• Does the table tilt and is there a suitable wedge available?
• Is there a range of equipment for difficult intubation: introducers, a range of laryngoscope blades and handles and endotracheal tubes ?
• Is there resuscitation equipment ready for the patient having a regional anaesthetic? What resuscitation equipment is ready for the baby?
• What sterile needles are available for spinal anaesthesia?
• Is there any monitoring equipment available ?

5. Problems with the anaesthetist

Finally, you should consider how experienced you are with any particular technique and how long you expect to take.

• Can you obtain the help of another anaesthetist?

This is a good policy if you are expecting a difficult intubation or other problems.

• Lastly, and probably as important as anything else, do you have a trained assistant?
• Do they know how to do cricoid pressure correctly?
• Are they strong enough to turn the patient on to her side if you get into trouble? Having considered all the potential difficulties, make a plan for your anaesthetic:

  Plan for Anaesthesia
  Preoperative preparation
  Perioperative	Induction
  	Maintenance
  	Recovery
  Postoperative care

   

  (Continued ...)

  
  

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