202410192201
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Tags: Obstetrics
Caesarean section
Caesarean delivery (CD) is the most performed inpatient surgery worldwide
Enhanced Recovery After Caesarean (ERAC) builds upon ERAS principles to address the unique needs and challenges of obstetric patients
Sedative agents
Sedating medications are typically avoided during CD to limit depressant effects for the fetus and maternal amnesia. However, small doses of sedative medications such as midazolam 0.02 mg/kg IV or 30-50% nitrous oxide may be safely administered when needed
Abx prophylaxis
Single dose first-generation cephalosporins (e.g., IV cefazolin 1 - 2g for patients <80 kg or >80 kg respectively) are the first-line antibiotic unless allergies exist. A higher dose is recommended (IV cefazolin 3g) for patients >120 kg
Alternatively, a single-dose combination of clindamycin and an aminoglycoside can be administered preoperatively
Antibiotic prophylaxis is recommended for all CDs within 60 minutes before the start of surgery unless the patient is already receiving antibiotics with an equivalent spectrum coverage, e.g., for chorioamnionitis
If not administered, such as in an emergency, antibiotics should be given as soon as possible after surgical incision. Surgical antimicrobial standards further dictate redosing antibiotics within 2 half-lives of the agent or at >1500 mL blood loss
Neuraxial block
Neuraxial anaesthesia is recommended for CD by SOAP, the Obstetric Anaesthetists' Association, American Pain Society and the National Institute for Health and Care Excellence
Bupivacaine, a long-acting local anesthetic, is the most common intrathecal agent used for CD. The hyperbaric form co-administered with opioids (ED95 11.2 mg for success) and isobaric form (ED95 13 mg for success) are similarly effective, although some evidence suggests more rapid sensory block onset with the hyperbaric formulation
Long-acting opioids such as intrathecal morphine produce postoperative analgesia lasting 13 - 33 hours
Intrathecal fentanyl and ITM are the preferred neuraxial adjuvants to local anaesthetic agents for CD anesthesia and analgesia. A dose-response study showed that 50 mcg ITM was as effective as 100 and 150 mcg
although the 50-mcg morphine dose has shown similar effectiveness to the 100 and 150 mcg dose with less pruritus and also likely less risk of respiratory depression, higher doses may benefit patients anticipated to have more severe pain, such as patients with a history of chronic pelvic pain
A meta-analysis concluded that high doses >100 mcg were more likely to be associated with adverse side effects
It is important to identify women with increased risk of respiratory depression, as they might require more intensive postoperative monitoring after ITM. The rate of clinically significant respiratory depression following contemporary doses of ITM is 1.08-1.63 per 10,000
Testing adequacy of block
The onset of sensory blockade to cold occurs before and at a higher level than pinprick, and both before and higher than touch, corresponding to inhibition of C, A delta and A beta fibers respectively
Cold > pinprick > touch
Evidence of S1 block (plantar flexion) is common with spinal anesthesia but infrequent with epidural anesthesia
Inadequate sacral anesthesia may be present if normal ankle motor function is observed and is likely to result in intraoperative pain
Neuraxial anaesthesia induced hypotension in CS
Intra-op pain during Caesarean section
IONV
Steps to prevent intra- and postoperative nausea and vomiting include avoiding hypotension, avoiding uterine exteriorization and administering a combination of prophylactic IV agents, including a 5-HT3 antagonist such as ondansetron 4 mg, or a glucocorticoid such as dexamethasone 4 to 8 mg
General anaesthesia for Caesarean section
SOAP guideline
The 25 interventions that SOAP recommends are:
- limiting the duration of fasting;
- nonparticulate liquid carbohydrate loading;
- patient education;
- promotion of breastfeeding and maternal-infant bonding;
- hemoglobin optimisation;
- prevention and treatment of hypotension caused by spinal anesthesia;
- maintenance of normothermia;
- optimising uterotonic administration;
- antibiotic prophylaxis;
- initiation of multimodal analgesia;
- IONV/PONV prophylaxis;
- intravenous (IV) fluid optimisation;
- delayed umbilical cord clamping;
- venous thromboembolism prophylaxis,
- encouraging rest periods;
- early mobilisation;
- early urinary catheter removal;
- early oral intake;
- facilitating early discharge;
- anaemia remediation;
- breastfeeding support;
- multimodal analgesia;
- glucose control;
- promotion of the return of bowel function
ERAS guideline
The ERAS Society has few recommendations specific to CD. They include delayed cord-clamping, prioritizing a transverse uterine hysterotomy, use of subcuticular sutures, and removal of the urinary catheter in the immediate postoperative period
Multimodal analgesia
‘Gold standard’ analgesia regimen recommendations for caesarean delivery summary (PROSPECT guideline)
| Pre-operative |
|---|
| Intrathecal morphine 50–100 μg or diamorphine ≤ 300 μg |
| Alternatively epidural morphine 2–3 mg or diamorphine ≤ 2–3 mg |
| Oral paracetamol |
| Intra-operative after delivery |
| Intravenous paracetamol if not administered pre-operatively |
| Intravenous non-steroidal anti-inflammatory drug |
| Intravenous dexamethasone |
| If intrathecal morphine not used, local anaesthetic wound infiltration (single shot) or continuous wound infusion and/or regional analgesia techniques (fascial plane blocks such as transversus abdominis plane blocks and quadratus lumborum blocks) |
| Post-operative |
| Oral or intravenous paracetamol |
| Oral or intravenous non-steroidal anti-inflammatory drugs |
| Opioid for rescue or when other recommended strategies are not possible (e.g. contra-indications to regional anaesthesia) Analgesic adjuncts include transcutaneous electrical nerve stimulation |
| Surgical technique |
| Joel-Cohen incision |
| Non-closure of peritoneum |
| Abdominal binders |
| PROSPECT guidelines recommend the use of postpartum epidural analgesia for OUD, due to the significantly increased postoperative opioid requirements expected. |
Current evidence suggests that the relatively low occurrence of chronic pain after CD compared to other surgical procedures may be attributed to factors such as neuraxial anaesthesia and potential protective effects from endogenous oxytocin secretion
Neuraxial anaesthesia during CD, particularly when intrathecal opioids are administered, may play a role in preventing the development of chronic pain, although current evidence does not support the role of intrathecal morphine (ITM) for this purpose
Opioids analgesics
Oral opioids such as oxycodone or hydrocodone should be preferentially prescribed unless the patient is intolerant of oral intake since greater opioid side effects are associated with the IV route of administration
Non-opioids analgesics
paracetamol & NSAID safe for breast feeding
NSAIDs should be prescribed in a scheduled manner rather than as-needed, as this strategy has been shown to reduce opioid consumption following caesarean delivery
Dexamethasone
Intravenous dexamethasone during CD has been associated with better pain scores and prolonged analgesia with reduced need for further anti-emetics
Gabapentin
Gabapentin exerts its analgesic effect by modulating the activity of voltage-gated calcium channels and enhancing GABA inhibitory neurotransmission. These mechanisms are thought to reduce pain signaling and dampen the central sensitization associated with postoperative pain
not much use in CS
Nerve blocks
TAP block
↓ pain if no ITM in first 24h
?? in the presence of ITM
QL block
↓ pain if no ITM
Would infiltration / catheters
no additional benefit if ITM present