Anaesthesia for LSCS
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Regional anesthesia such as spinal or epidural anesthesia is preferred over general anesthesia for cesarean sections due to lower risks for both mother and baby. Spinal anesthesia provides rapid onset but a finite duration, while epidural anesthesia allows for gradual onset and better control of sensory levels via a catheter. Both techniques require careful management of hypotension through fluid administration and vasopressors. Neuraxial opioids can enhance analgesia without negatively impacting the neonate. The goals are to provide adequate anesthesia and analgesia for surgery and postoperatively while maximizing safety for mother and baby.
Anaesthesia for LSCS
- 1. Anaesthesia For LSCS Dr. Himanshu Jangid
- 2. Indications for a LSCS The most common indications for cesarean delivery include “failure to progress,” non-reassuring fetal status, cephalopelvic disproportion, malpresentation, prematurity, and previous uterine surgery.
- 3. Problems Due To Physiological Changes The pregnant uterus compresses the vena cava and the aorta and obstructs blood flow. The conscious patient can respond by improving her position, but under general anaesthesia this is impossible. Spinal or epidural anaesthesia considerably worsens the problem due to the sympathetic blockade produced. By tilting the patient to the left by about 15 degrees the pressure from the uterus on the vena cava is reduced. This can be achieved by tilting the operating table or by placing a wedge under the patient's right buttock.
- 4. Problems Due To Physiological Changes Diminished tone in the lower oesophageal sphincter in later pregnancy the raised intra-abdominal pressure altered gastro-oesophageal angle make gastric reflux more likely. In labour the administration of opioids markedly slows gastric emptying. During induction of anaesthesia passive regurgitation of stomach contents into the pharynx may occur, and lead to aspiration pneumonia.
- 5. Problems Due To Physiological Changes This is likely if the pH of the stomach contents is less than 3 (very acidic) and more that 30 mls of fluid is aspirated. Minimized by using local anaesthesia instead of general anaesthesia when possible, by reducing food intake in labour to minimise stomach contents and by a careful rapid sequence induction of anaesthesia using cricoid pressure The stomach acid should also be neutralised if a Caesarean section is planned. An intravenous H2 blocker such as ranitidine or cimetidine is effective but takes an hour to work. An antacid such as 30mls of 0.3 Molar sodium citrate is reliable if given immediately before induction of anaesthesia and will last about 1 hour
- 6. Problems Due To Physiological Changes There is a greater increase in plasma volume than red cell mass causing dilutional anaemia. Cardiac output is increased. Patients with cardiac disease (either congenital or valvular) are at particular danger during pregnancy.
- 7. Problems Due To Physiological Changes There is a decrease in the resting lung volume caused by pressure from the enlarged uterus, There is an increase in the basal metabolic rate. Oxygen reserves are therefore diminished Hypoxia develops rapidly if airway problems occur.
- 8. Problems Due To Physiological Changes Many drugs used in anaesthesia cross the placental barrier Thus may affect the fetus, particularly opioids such as morphine and sedatives such as diazepam. During anaesthesia these drugs should be avoided until the umbilical cord has been clamped.
- 9. Goals General goals in choosing anesthesia are (1) the safety of the mother; (2) the safety of the baby; (3) the comfort of the mother (4) the ability to perform the surgery under that anesthetic technique.
- 10. Choice of Anaesthesia The choice of anesthesia for cesarean section is determined by multiple factors indication for operating, its urgency, patient and obstetrician preferences, and the skills of the anesthetist.
- 11. Choices for Anaesthesia Neuraxial Anesthesia Spinal Anesthesia Epidural Anesthesia CSE Continous spinal General Anaesthesia
- 12. Regional vs General Anaesthesia Regional anesthesia has become the preferred technique General anesthesia has been associated with higher maternal mortality. Deaths associated with general anesthesia related to airway problems, such as inability to intubate, inability to ventilate, or aspiration pneumonitis, whereas deaths associated with regional anesthesia are related to excessively high neural blockade local anesthetic toxicity.
- 13. Regional vs General Anaesthesia Advantages of regional anesthesia include (1) Less neonatal exposure to potentially depressant drugs, (2) A decreased risk of maternal pulmonary aspiration, (3) An awake mother at the birth of her child, with the father also present if desired, and (4) The option of using spinal opioids for postoperative pain relief. The choice between spinal and epidural anesthesia is often based on physician preferences.
- 15. Spinal Anaesthesia Advantages It has a very rapid onset and provides a dense neural block. Little risk of local anesthetic toxicity and minimal transfer of drug to the fetus. Failures (including incomplete or patchy blocks) are very infrequent with spinal anesthesia. Disadvantages The finite duration of anesthesia A higher incidence of hypotension.
- 16. Spinal Anaesthesia Hyperbaric solutions : adjust block height by adjusting table position. Despite achieving an adequate (T4) block, some degree of visceral discomfort during cesarean section, particularly in situations in which the obstetrician exteriorizes the uterus. The quality of the spinal anesthesia can be improved by the addition of epinephrine, morphine,fentanyl, or sufentanil.
- 17. Spinal Anaesthesia Hyperbaric bupivacaine is the most commonly used agent Its duration of action of 1.5 to 2 hours is well matched to the duration of surgery in most cases. Most practitioners now use a set dose of hyperbaric bupivacaine. Neither patient height, weight, nor body mass index appears to correlate with block height. Doses above 15 mg significantly increase the risk of complications, including high block, and are not recommended.
- 18. Spinal Anaesthesia Epinephrine 0.1 mg can enhance the quality of the block Adding 12.5–25 mcg of fentanyl or 5–10 mcg of sufentanil to the local anesthetic solution enhances the intensity of the block and prolongs its duration without adversely affecting neonatal outcome. Addition of preservative-free morphine, 0.2–0.3 mg, can prolong postoperative analgesia up to 24 h but requires special monitoring for delayed postoperative respiratory depression.
- 19. Spinal Anaesthesia Cesarean section requires a T4 sensory level. Because of the associated high sympathetic blockade, all patients should receive a 1000- to 1500-mL bolus of lactated Ringer's injection prior to neural blockade. Crystalloid boluses do not consistently prevent hypotension but can be helpful in some patients. Smaller volumes (250–500 mL) of colloid solutions, such as albumin or hetastarch, are more effective.
- 20. Spinal Anaesthesia After injection of the anesthetic, the patient is placed supine with left uterine displacement; supplemental oxygen (40–50%) is given; blood pressure is measured every 1–2 min until it stabilizes. Intravenous ephedrine, 10 mg, should be used to maintain systolic blood pressure > 100 mm Hg. Small intravenous doses of phenylephrine, 25–100 mcg, or an infusion up to 100 mcg/min may also be used safely.
- 21. Spinal Anaesthesia Some studies suggest less neonatal acidosis with phenylephrine compared to ephedrine. Prophylactic administration of ephedrine (5 mg intravenous or 25 mg intramuscular) has been advocated by some clinicians for spinal anesthesia, as precipitous hypotension may be seen but is not recommended for most patients because of a risk of inducing excessive hypertension.
- 22. Spinal Anaesthesia Hypotension following epidural anesthesia typically has a slower onset. Slight Trendelenburg positioning facilitates achieving a T4 sensory level and may also help prevent severe hypotension. Extreme degrees of Trendelenburg may interfere with pulmonary gas exchange.
- 23. Epidural Anaesthesia Epidural anesthesia is preferred over spinal anesthesia by some clinicians because of the more gradual decrease in blood pressure associated with epidural anesthesia. Continuous epidural anesthesia also allows better control over the sensory level. Epidural anesthesia for cesarean section is generally most satisfactory when an epidural catheter is used.
- 24. Epidural Anaesthesia The catheter facilitates achieving an initial T4 sensory level, allows supplementation if necessary, and provides an excellent route for postoperative opioid administration. After a negative test dose, a total of 15–25 mL of local anesthetic is injected slowly in 5-mL increments.
- 25. Epidural Anaesthesia Lidocaine 2% (with or without 1:200,000 epinephrine) or chloroprocaine 3% is most commonly used. Addition of fentanyl, 50–100 mcg, or sufentanil, 10–20 mcg, greatly enhances the intensity of the block and prolongs its duration without adversely affecting neonatal outcome. sodium bicarbonate (7.5% or 8.4% solution) to local anesthetic solutions to increase the concentration of the nonionized free base and produce a faster onset and more rapid spread of epidural anesthesia. (1 mEq/10 mL of lidocaine and 0.05 mEq/10 mL of bupivacaine or ropivacaine)
- 26. Epidural Anaesthesia If pain develops as the sensory level recedes, additional local anesthetic is given in 5-mL increments to maintain a T4 sensory level. "Patchy" anesthesia prior to delivery of the baby can be treated with 10–20 mg of intravenous ketamine or 30% nitrous oxide. After delivery, intravenous opioid supplementation may also be used, provided excessive sedation and loss of consciousness are avoided.
- 27. Epidural Anaesthesia Pain that remains intolerable and unresponsive to these measures necessitates general anesthesia with endotracheal intubation. Nausea can be treated intravenously with ondansetron 4 mg or metoclopramide 10 mg.
- 28. Epidural Anaesthesia Epidural morphine, 5 mg, at the end of surgery provides good to excellent pain relief postoperatively for 6–24 h. An increased incidence (3.5–30%) of recurrent herpes simplex labialis infection has been reported 2–5 days following epidural morphine in some studies. Postoperative analgesia can also be provided by continuous epidural infusions of fentanyl, 25–75 mcg/h, or sufentanil, 5–10 mcg/h, at a volume rate of approximately 10 mL/h. Epidural butorphanol, 2 mg, can also provide effective postoperative pain relief, but marked somnolence is often a troublesome side effect.
- 29. CSE Technique Provides rapid onset of dense surgical anesthesia while allowing the ability to prolong the block with an epidural catheter. Because the block can be supplemented at any time, the CSE technique allows the use of smaller doses of local spinal anesthetics thus reduce the incidence of high spinal block and hypotension. Potential problems of the CSE technique for cesarean delivery include an inability to test the catheter, the possibility of a failed epidural catheter after spinal injection, the risk of enhanced spread of previously injected spinal drug after use of the epidural catheter.
- 30. CSE Technique The classic technique required the use of large-bore epidural needles; newer techniques use a 32-gauge microcatheter inserted through a 26-gauge spinal needle. Abandoned after withdrawal of these catheters by the FDA. The advantages of continuous spinal anesthesia, however, remain, and macrocatheters (e.g., placing an epidural catheter intrathecally) can be used in high-risk parturients.
- 31. Continuous spinal anesthesia To perform continuous spinal anesthesia, the anesthesiologist pierces the dura with an epidural needle and then threads the epidural catheter 3 to 4 cm within the intrathecal space. Catheter placement can be tested by aspiration of CSF. Because a catheter is being used, smaller doses can be given in an incremental fashion. Such administration is particularly advantageous in high-risk parturients such as those with cardiac disease, respiratory disease, morbid obesity, and neuromuscular disease.
- 32. Continuous spinal anesthesia To reduce the risk of headache after this technique, The epidural needle should be turned so that it is parallel to the dural fibers at the time of insertion. Leaving the epidural catheter in situ for more than 12 hours Injecting a bolus of preservative-free normal saline before removal of the catheter.
- 34. General Anaesthesia Advantages: It can be given very quickly, blood pressure is more easily controlled, breathing is more easily controlled once the ability to breathe for the patient is obtained. On patients with bleeding and clotting abnormalities, patients with neurological problems, patients with infections that might be spread to the spinal area if regional anesthesia is done, etc.
- 35. General Anaesthesia Disadvantages: the mother is unconscious and therefore unable to participate in the process of birth or interact with the baby once it is delivered. After the operation, general anesthesia wears off relatively quickly and can result in greater postoperative pain.
- 36. Pre operative preparation Prophylaxis against severe nonparticulate aspiration pneumonia with 30 mL of 0.3 M sodium citrate 30–45 min prior to induction. Intravenous ranitidine, 50 mg, and/or metoclopramide, 10 mg, 1–2 h prior to induction; such factors include morbid obesity, symptoms of gastroesophageal reflux, a potentially difficult airway, or emergent surgical delivery without an elective fasting period. Premedication with oral omeprazole, 40 mg, at night and in the morning also appears to be highly effective in high-risk patients
- 37. Pre operative preparation Although anticholinergics theoretically may reduce lower esophageal sphincter tone, premedication with a small dose of glycopyrrolate (0.1 mg) helps reduce airway secretions and should be considered in patients with a potentially difficult airway.
- 38. Pre operative preparation Caesarean sections are frequently performed as emergencies in unprepared patients. The procedure may be complicated by an unfasted patient, fetal distress, severe haemorrhage, pre-eclampsia etc. Prepare and check equipment for obstetric anesthesia in advance, so that your apparatus and drugs are immediately to hand. This saves valuable time in an urgent case. Particular attention should be paid to the function of the laryngoscopes, the endotracheal tube and cuff, and the suction apparatus.
- 39. Suggested Technique of General Anesthesia for Cesarean Section 1. Administer a nonparticulate antacid. Additional agents such as metoclopramide or an H2 blocker should be considered in patients at high risk for aspiration or failed intubation. 2. Apply routine monitors, including electrocardiography, pulse oximetry, and capnography. Ensure that suction is functioning and that equipment to correct failed intubation is readily available. 3. Position the patient in a manner to achieve left uterine displacement and optimal airway position. 4. De-nitrogenate with a high flow of oxygen for 3-5 minutes or 4 vital capacity breaths.
- 40. Technique of General Anesthesia After the drapes are applied and the surgeon is ready, initiate a rapid-sequence induction with thiopental, 4.0-5.0 mg/kg, and succinylcholine, 1.0-1.5 mg/kg. Apply cricoid pressure and continue until correct position of the endotracheal tube is verified and the cuff is inflated.
- 41. Technique of General Anesthesia In hypotensive crises, ketamine, 1.0-1.5 mg/kg, should be substituted for thiopental. A defasciculating dose of muscle relaxant is not necessary. 6. Ventilate with 50% oxygen and 50% nitrous oxide and a volatile anesthetic as necessary. Maintain normocarbia and use muscle relaxation as necessary with either a nondepolarizing muscle relaxant or succinylcholine infusion.
- 42. Technique of General Anesthesia 7. After delivery, increase nitrous oxide to 70%, discontinue or reduce the volatile anesthetic, and administer an opioid and a benzodiazepine. Add oxytocin to intravenous fluids. 8. Insert an orogastric tube before completion of surgery. 9. Reverse neuromuscular blockade as necessary at completion of surgery. 10. Extubate when the patient is awake, the anesthesia is adequately reversed, and the patient is following commands.
- 43. Failed Intubation Physical changes associated with pregnancy, including weight gain, enlarged breasts, oropharyngeal edema Mallampati class 4 airway, a short neck, protruding maxillary incisors, and mandibular recession, can complicate endotracheal intubation.
- 44. Failed Intubation drill Failed intubation drill. An appropriate course of action is as follows: Maintain cricoid pressure. Oxygenate using the facemask. Turn the patient on to the left side into a head down position and allow her to wake up. Proceed with local anaesthetic block when the patient has regained consciousness. If the operation is needed very urgently (eg for fetal distress or an antepartum haemorrhage), re-establish spontaneous respiration after the suxamethonlum has worn off, and continue the anaesthetic under a facemask using nitrous oxide, oxygen and halothane or an ether based technique. If problems are encountered with the airway, it may be necessary to wake the patient up and use a regional technique. At all times ensure that the patient is well oxygenated.
- 46. Pre eclampsia Preeclampsia has been defined as hypertension occurring after 20 weeks’ gestation or in the early postpartum period and returning to normal within 3 months after delivery or onset after 20 weeks’ gestation and at least one of the following: • Proteinuria higher than 300 mg/24 hr • Oliguria or a serum-plasma creatinine ratio greater than 0.09 mmol/L • Headaches with hyperreflexia, eclampsia, clonus, or visual disturbances • Increased liver enzymes, plasma glutathione S-transferase-alpha 1-1, or serum alanine aminotransferase or right abdominal quadrant pain • Thrombocytopenia, increased lactate dehydrogenase (LDH), hemolysis, disseminated intravascular coagulation (DIC) • Intrauterine growth retardation
- 47. Pre eclampsia Clinical Features The upper airway may become edematous in a preeclamptic woman and result in the potential for airway compromise or difficulty in intubation, Pulmonary edema occurs in up to 3% of these patients. The cardiovascular effects of preeclampsia 1. Hyperdynamic circulation, high cardiac output, normal to increased systemic vascular resistance (SVR), and normal or slightly decreased blood volume and filling pressures 2. Normal cardiac output and lower filling pressures, but increased SVR 3. Highly elevated SVR, but reduced blood volume and decreased left ventricular function
- 48. Pre eclampsia Treatment The mainstay of therapy in preeclampsia is control of hypertension, prevention of seizures, and delivery of the fetus. Hydralazine and labetalol are commonly used as antihypertensives Other agents include nitroglycerin, nifedipine, and esmolol. Sodium nitroprusside may also be used, but only in the short term because of a risk of cyanide toxicity in the fetus.
- 49. Pre eclampsia Magnesium sulfate is the drug of choice for seizure control and prevention of recurrent eclamptic seizures. Initial dosing is 4 g MgSO4 given intravenously over a 10-minute period, followed by a maintenance infusion at 1 g/hr. In the presence of renal failure, the rate of infusion should be modified by evaluating serum magnesium levels. Magnesium has a narrow therapeutic index, with serum levels between 2 and 3.5 mmol/L being safe and effective.
- 50. Anesthetic management Anesthetic management of a preeclamptic patient includes a detailed preanesthetic assessment that focuses on the severity of the condition, associated features and systemic involvement, evaluation of the airway, fluid status, and blood pressure control. Investigations should include a complete blood cell count, renal profile, and liver function tests.
- 51. Anesthetic management Coagulation studies should be performed. However, before considering neuraxial analgesia or anesthesia, a recent platelet count should be evaluated. DIC may require the administration of whole blood, platelets, fresh frozen plasma, and cryoprecipitate. Initiation of neuraxial analgesia during DIC is contraindicated.
- 52. Anesthetic management Neuraxial (epidural, spinal and combined spinal-epidural) techniques offer many advantages for labor analgesia and can be safely administered to the parturient with preeclampsia. Dilute epidural infusions of local anesthetic plus opioid produce adequate sensory block without motor block or clinically significant sympathectomy. the risk of a failed endotracheal intubation must be weighed against the risk of transient hypotension when deciding between general and regional anesthesia for cesarean delivery for the patients with severe preeclampsia-eclampsia.
- 53. CONCLUSION To summarize, general anesthesia should be utilized only for a true emergency when the situation will not allow any other options. Regional anesthesia (either spinal or epidural) offers an effective means of anesthesia for cesarean section while allowing the mother to remain awake The regional techniques also offer some advantages for the control of pain after the operation. As with any anesthetic, make sure you discuss the options, risks and benefits with a anesthesiologist who know your individual condition and situation.
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