Analgesia following caesarean section does not differ in basics from analgesia for a lower abdominal operation in a young and, usually fit, individual. The positive attitude of the patient, however, is of assistance in achieving good results and early mobility.
If spinal anaesthesia is used, it is my practice to use parenteral analgesia. My preference is for opiate patient controlled analgesia (PCA) with oral NSAIDs to control 'afterpains'. NSAIDs can cause uterine atony (and increase uterine bleeding) and should only be used if no other contraindication exists (peptic ulcer, asthma, renal disease, allergy). Ketorolac is an alternative, especially if opioids cause nausea (1, 2) .
If epidural anaesthesia is used it should be continued for postoperative analgesia, a method of pain relief equal or superior to others (3, 4, 5). Although some dispute this (6, 7), the majority opinion favours a mixture of an opioid and bupivacaine(less than or equal to 0.125 %) (8, 9, 10). It is important to use a loading dose followed by a maintenance infusion or maintenance PCA to produce the best results (11). Effect and vital signs need to be monitored regularly. The Prince Henry Hospital pain scale (7) (Figure 99.1)provides an objective measure. A pain score of 0 or 1 should be achieved using this scale.
The choice of opioid is also disputed, but all high intrinsic activity opioids are effective (Figure 99.2). Morphine has the lowest ratio of epidural:systemic dose (Figure 99.3) and the best quality of analgesia (11) but, also, the highest incidence of delayed respiratory depression and the slowest onset. Fentanyl is widely used and alfentanil is considered optimal by some (11).
Important adverse effects of these techniques include delayed respiratory depression, urinary retention, hypotension, drowsiness, nausea, vomiting and itch.
References:
1. Merry AF et al. Br J Anaesth 69:92-4, 1992
2. Bonnet F and Vesinet C. Cahiers dAnesthesiologie 42:191-4, 1994.
3. Cohen SE and Woods WA. Anesthesiology 58:500-4, 1983.
4. Perriss BW et al., Br J Anaesth 64:355-7, 1990.
5. Salomaki TE et al., Anesthesiology 75:790-5, 1991.
6. Badner NH et al., Can Anesth Soc J 39:330-6,1992.
7. Torda TA et al., Br J Anaesth 74:35-40, 1995.
8. Millon D et al., Ann Fr dAnesth Reanim 2:273-9, 1983.
9. Gaffud MP et al., Anesthesiology 65:331-4, 1986.
10. Paech MJ et al., Anaesth Int Care 18:22-30, 1990.
11. Chrubasik J, Chrubasik S, Mather L, Postoperative Epidural Opioids, Springer, Berlin, 1993.