Anesthesia for tubal ligation

Published on 07/02/2015 by admin

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Last modified 22/04/2025

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Anesthesia for tubal ligation

Scott A. Gammel, MD

Tubal ligations are performed either as an interval (not postpartum) procedure or as an immediate postpartum procedure using local, regional, or general anesthesia.

Interval tubal ligations

Laparoscopy is the most common surgical approach for interval tubal ligations. Anesthetic considerations include those related to pneumoperitoneum, head-down positioning (with related cardiovascular and pulmonary changes), and other potential complications.

Pneumoperitoneum is performed via a needle inserted at the lower margin of the umbilicus (a relatively avascular and thin portion of the abdominal wall). An incorrectly placed needle can lead to insufflation of the abdominal wall, retroperitoneum, mesentery, omentum, or bowel. CO2 is the gas of choice to perform pneumoperitoneum because it is highly soluble, is rapidly absorbed postoperatively, and provides a margin of safety if injected intravascularly. N2O is less soluble and is not eliminated as quickly, but its use is associated with less peritoneal and diaphragmatic irritation and less postoperative shoulder pain.

Head-down (Trendelenburg) positioning is associated with brachial plexus injury if shoulder rests are used (as a result of clavicular compression of nerve roots); however, current guidelines recommend that shoulder rests not be used for patients in the Trendelenburg position. Because the Trendelenburg position results in decreased functional residual capacity, decreased pulmonary compliance, and altered stomach position, tracheal intubation will reduce the risk of pulmonary aspiration and atelectasis. Mainstem intubation may result from cephalad shift of the mediastinum and carina.

Cardiovascular changes result from increased intraabdominal pressure, patient position, anesthesia, and hypercarbia. Decreases in cardiac output, increased peripheral and pulmonary vascular resistance, increased arterial pressure, and arrhythmias may result.

Respiratory changes include decreased vital capacity, decreased functional residual capacity, increased blood volume, and decreased pulmonary compliance, which can lead to atelectasis. Peak inspiratory pressures increase. A significant increase in arterial CO2 (15% to 25%) and decrease in pH occur during general anesthesia when CO2 is used for insufflation because of absorption of CO2 from the pneumoperitoneum. Spontaneous ventilation can also lead to significant hypercarbia.

Other complications include hemorrhage, (accounting for almost half of complications), cardiac arrhythmias (some of which may result from reflex increases in vagal tone from peritoneal stretching or electrocautery of fallopian tubes), gas embolism, pneumothorax, pneumomediastinum, pneumopericardium, and mesenteric ischemia. Complications from creation of pneumoperitoneum and placement of trocars are more common with laparoscopy performed for tubal ligation than with laparoscopy for gastrointestinal surgery.

Anesthetic techniques

General anesthesia

After intravenous induction takes place, O2, N2O, and an inhaled anesthetic agent are used to maintain anesthesia. This is supplemented with short-acting opioids and neuromuscular blocking agents.

Common postoperative complications of general anesthesia are abdominal and shoulder pain and postoperative nausea and vomiting (PONV). Increasing the volume of infused preoperative and intraoperative fluids reduces the incidence of PONV and improves hemodynamic response to pneumoperitoneum and postoperative recovery.

Metoclopramide (10-20 mg, administered intravenously 15-30 min before induction) and droperidol (0.5-1.0 mg, administered 3-6 min before induction) are synergistic in decreasing nausea, vomiting, and recovery time. Droperidol alone (0.625-2.15 mg) administered after intubation is an effective antiemetic for outpatient tubal ligation, and its use shortens time in the postanesthesia care unit. Ondansetron (4-8 mg, administered intravenously) before induction also significantly reduces the incidence of PONV.

Postpartum tubal ligation

The American Society of Anesthesiologists provides published guidelines concerning postpartum tubal ligations in section VI of their “Practice Guidelines for Obstetric Anesthesia” (Box 190-1). In addition to following these guidelines, it is prudent to also check the patient’s preoperative hemoglobin level because determining blood loss at delivery may be difficult.

Box 190-1   Summary of Postpartum Tubal Anesthesia Guidelines from American Society of Anesthesiologists Practice Guidelines for Obstetric Anesthesia

Anesthetic techniques

General anesthesia

The increased risk of aspiration occurring in the postpartum period probably warrants the prophylactic use of an H2-receptor antagonist, nonparticulate antacid, and metoclopramide with rapid sequence induction and application of cricoid pressure for the postpartum woman undergoing tubal ligation.

Halogenated inhaled anesthetic agents cause dose-related uterine relaxation and, therefore, increase the risk of hemorrhage, especially in multiparous women. The reduced minimum alveolar concentration of an inhaled anesthetic agent that occurs in the postpartum period returns to normal 12 to 36 h after delivery. Propofol anesthesia (induction and maintenance) provides a lower incidence of PONV and rapid awakening, with low concentrations in breast milk 4 and 8 h postoperatively.

Plasma cholinesterase activity is significantly lower in postpartum women than in women who are not postpartum, even compared with pregnant women; therefore, blockade with succinylcholine, rocuronium, mivacurium, or vecuronium is prolonged in the postpartum period; however, when the dose of rocuronium is based on lean body mass, blockade is not prolonged. Neuromuscular blockade is unchanged with atracurium and is shortened with cisatracurium. Metoclopramide inhibits plasma cholinesterase and prolongs succinylcholine neuromuscular blockade by 100% to 200%.

Neuraxial anesthesia

Neuraxial anesthesia for postpartum tubal sterilizations provides excellent operating conditions and is the most common anesthetic technique used for this indication in the United States. Airway risk (obstruction, hypoventilation, and aspiration) is significantly reduced, as compared with general anesthesia. A T4 block provides excellent operating conditions and pain relief. A T10 block may be inadequate, especially if it is difficult to mobilize the uterus during surgery. Sedation that prolongs postoperative amnesia should be avoided to improve early maternal-neonate interaction and bonding.

Although epidural catheters used for labor are more likely to fail when used for tubal ligation if surgery is delayed for more than 10 h after delivery, success rates are still high for up to 24 h after delivery. Postpartum use of an epidural catheter is more likely to be successful when a multiorifice catheter is placed 4 to 6 cm into the epidural space and secured to the patient’s skin while her back is not flexed.

Starting 18 h postpartum, there is a progressive decrease in dermatomal spread of epidural anesthesia, compared with the spread in patients given epidurals for cesarean section. At 36 h postpartum, there is no significant difference in spread between women who have recently delivered and nonpregnant patients.

Spinal anesthesia has a very positive risk-benefit profile. The risk of local anesthetic toxicity is almost nil compared with epidural anesthesia. Rapidity of onset (and offset) and density of block are very favorable. The risk of postdural puncture headache when using small-gauge or pencil-point-design spinal needles is low and may be no different than with epidural anesthesia.

Local anesthetic requirements (which are lessened by 30% in pregnant women) return to nonpregnant levels within 12 to 36 h after delivery and appear to be associated with rapid decline in progesterone levels. There is a faster onset, higher level, and longer duration of spinal anesthesia in term patients than in young gynecologic patients. There is also a progressive decline in duration of block during the first 3 days postpartum.

Cardiovascular effects are markedly decreased in postpartum patients (no aortocaval compression and maternal autotransfusion at delivery), as compared with pregnant women. The need for treatment of hypotension after spinal anesthesia is lower (<10%), compared with patients undergoing cesarean section (>80%).

To avoid the transient neurologic symptoms associated with the use of hyperbaric lidocaine and hyperbaric bupivacaine, preservative-free meperidine (intrathecal formulation) at a dose of 1 mg/kg based on the patient’s prepregnant weight (usual range 50-80 mg) may be used. The onset time of intrathecal meperidine is 3 to 5 min, with a duration of 30 to 60 min. The use of 60 mg of meperidine or 70 mg of 5% lidocaine have similar rates of PONV and patient satisfaction, but meperidine provides a notably longer postoperative analgesia. Pruritus occurs more often with meperidine.

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