Anesth Analg 1999;89:1269
© 1999 International Anesthesia Research Society
OBSTETRIC ANESTHESIA
Postpartum Tubal Ligation: Safety, Timing, and Other Implications for Anesthesia
Brenda A. Bucklin, MD*, and
Carl V. Smith, MD
Departments of
*Anesthesiology and
Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha, Nebraska
Address correspondence to Brenda Bucklin, MD, University of Nebraska Medical Center, Department of Anesthesiology, 984455 Nebraska Medical Center, Omaha, NE 68198-4455.
 |
Introduction
|
|---|
Tubal sterilization has emerged as the form of birth control most frequently used by women in the United States (1), and this procedure is often performed after vaginal or cesarean delivery. Several factors should be considered by the obstetrician and anesthesiologist before proceeding with postpartum tubal ligation. Although technically easier for obstetricians and more convenient for both patient and obstetrician, anesthetic concerns may influence the timing of postpartum tubal ligation. This article will review the timing and controversial issues surrounding postpartum tubal ligation.
 |
Timing of Tubal Sterilization
|
|---|
Recently, the American Society of Anesthesiologists Task Force on Obstetric Anesthesia published Practice Guidelines for Obstetric Anesthesia, including recommendations regarding postpartum tubal ligation (2). Because there was insufficient literature to evaluate the comparative benefits of local, spinal, epidural, or general anesthesia, these recommendations were based largely on clinical opinion. The task force concluded that, in many patients, postpartum tubal ligation can be performed safely.
Questions often arise from obstetricians and anesthesiologists regarding the timing of postpartum tubal ligation. With reductions in length of hospital stay after childbirth, tubal ligations are being performed earlier. Postpartum sterilization within 8 h of delivery is reasonable when the maternal medical history is uncomplicated and if the delivery was devoid of significant complications. Because the uterine fundus is located at the level of the umbilicus, access to the fallopian tubes is facilitated through a small subumbilical incision. Additional expense and time of interval sterilization is avoided, and infant separation minimized. A major disadvantage of postpartum sterilization after vaginal or cesarean delivery is that there may be inadequate time to properly assess the newborn. If the newborn requires resuscitation or is unexpectedly transferred to the neonatal intensive care unit, tubal ligation may be delayed for the consideration of a subsequent pregnancy.
Assessment of hemodynamic status and consideration of anesthetic risks are important for all patients undergoing postpartum tubal ligation; however, specific maternal risk factors have not been identified. Because physiologic changes of pregnancy resolve in the early postpartum period, the decision whether to proceed with sterilization in a high-risk patient must be considered when a subsequent pregnancy could contribute to maternal morbidity/mortality. Although postpartum tubal ligation in the preeclamptic patient has not been thoroughly evaluated, Vincent and Martin (3) reported the absence of profound hemodynamic alterations in response to spinal or epidural anesthesia in patients with preeclampsia undergoing postpartum tubal sterilization.
Another factor concerning the timing of tubal ligation is the adequacy of labor and delivery staffing. The American Society of Anesthesiologists Practice Guidelines for Obstetric Anesthesia (2) and the American College of Obstetricians and Gynecologists Committee Opinion on Postpartum Tubal Ligation (4) both state that such a procedure should not be performed when it compromises other aspects of patient care. Patients should understand that a desired and agreed-upon elective postpartum procedure cannot be guaranteed. Hospitals that commit to providing this service should have a mechanism to provide temporary increases in staffing in order to avoid canceling as few procedures as possible. Because temporary staffing increases could increase paid overtime, an alternative might be tubal sterilizations performed in other in-hospital operating room locations.
 |
What Is the Anesthetic Risk for Postpartum Tubal Ligation?
|
|---|
The true anesthetic risk for postpartum sterilization performed within 8 h of delivery is unknown. Although Hawkins et al. (5) reported characteristics of anesthesia-related deaths during obstetric delivery in the United States from 19791990, postpartum tubal ligation was not specifically identified as a risk for anesthesia-related complications. In 1983, Peterson et al. (6) estimated that three million tubal sterilizations had occurred between 1977 and 1981. Twenty-nine deaths (0.0000096%) were documented in this retrospective report, which included both interval and postpartum sterilizations. Eleven deaths (0.0000036%) were attributed to complications of general anesthesia, with hypoventilation causative or contributing to six of these deaths. None of the women whose deaths were attributed to hypoventilation had been tracheally intubated. The remaining deaths resulted from cardiorespiratory arrests of unknown cause. Applying a case-fatality rate for tubal sterilization procedures of 3.6/100,000 procedures (7), Peterson et al. concluded that the 29 deaths "may not represent all of the sterilization-attributable deaths that occurred from 1977 - 1981" and estimated that the report contains only "27% of the projected sterilization-attributable deaths." Other epidemiologic surveys, however, have also reported similarly low maternal mortality rates (810). Because much of this data includes laparoscopic and laparotomy sterilizations performed after the 8- postpartum period, it is difficult to separate the risk of sterilizations occurring within and after 8 h of delivery. Although the true anesthetic risk of tubal sterilization performed within 8 h of delivery is unknown, many sterilizations are performed within this time period, and reports of complications are rare.
 |
General Anesthesia for Postpartum Tubal Ligation
|
|---|
The Practice Guidelines for Obstetric Anesthesia suggests that the decision to use a particular anesthetic technique (i.e., regional versus general) should be individualized, based on anesthetic and/or obstetric risk factors and patient preference (2). The decision to provide general anesthesia within 8 h of delivery should be considered carefully. Reports of airway risk and difficult intubation in obstetrics almost always result from cesarean deliveries, with the incidence of failed intubation varying from 1 in 300 (11) to 1 in 750 (12) for patients undergoing cesarean delivery. However, the clinical circumstances of tubal sterilization and cesarean delivery are frequently different. Because emergency surgery has been identified as a risk factor for anesthesia-related maternal mortality (8), the urgency of cesarean delivery may contribute to overall airway difficulty. Although others have reported cases of failed intubation before nonemergent cesarean delivery (11), it is difficult to determine how situational differences contribute to overall airway risk. Although physiologic changes of pregnancy resolve rapidly after delivery, anecdotal reports suggest that airway changes can persist for an unspecified period after delivery as a result of maternal expulsive efforts (13), which may contribute to laryngeal edema and airway difficulty during postpartum tubal sterilization (13).
 |
Aspiration Risk and Postpartum Gastric Emptying
|
|---|
In addition to airway changes during pregnancy and the puerperium, delays in gastric emptying may persist during the early postpartum period. Although many techniques have been used to evaluate gastric emptying during the postpartum period, studies have produced conflicting results. Problems with these studies include small sample size, lack of control group measurements, intersubject variability, and differences in measurement techniques. Many of the studies also lack measurements during the 2- and 8-h postpartum period. Although postpartum gastric emptying studies often present technical and ethical challenges, several studies do provide clinically relevant information to anesthesiologists. Some reports suggest important contributors to delayed gastric emptying during labor and postpartum include solid food consumption (14,15) and intrapartum administration of parenteral (16,17) or epidural opioids (18,19).
The Practice Guidelines for Obstetric Anesthesia recommends that patients planning to have an elective postpartum tubal ligation within 8 h of delivery should have no oral intake of solid foods during labor and postpartum until the time of surgery (2). Ultrasound is useful for evaluating gastric emptying (20), and two real-time ultrasound studies (14, 15) support the above recommendation. Although these studies do not compare the emptying of solids and liquids and the pattern of emptying for solids does not predict the emptying pattern of liquids (20), data evaluating intrapartum gastric emptying of liquids are lacking. Carp et al. (14) evaluated stomach contents of nonpregnant, nonlaboring, and laboring parturients. A small subset of laboring patients who were receiving epidural local anesthetics without parenteral or epidural opioids underwent ultrasound scans every 2 h during labor and postpartum. Solid food was present throughout labor. Emptying occurred only 46 h after delivery. Another ultrasound study evaluated postpartum patients, nonpregnant volunteers, postpartum tubal ligation patients, and patients presenting for interval tubal sterilization (15). Comparisons of patients who underwent postpartum tubal ligation versus interval sterilization indicated that a greater number of postpartum tubal ligation patients had evidence of solid food at least 6 h after delivery. The authors concluded that a considerably greater number of postpartum patients had delayed gastric emptying and that women presenting for postpartum tubal sterilization may have solid food present in the stomach.
Several studies have suggested that additional postpartum delays occur when parenteral or epidural opioids are administered during labor. These studies have used epigastric impedance and paracetamol absorption to detect delays in gastric emptying. Although there are limitations associated with the paracetamol absorption technique, the technique is noninvasive and has been used to obtain much of the published gastric emptying data. Using the paracetamol technique, Nimmo et al. (16) measured the rate of gastric emptying in women during labor. Although this study lacked nonpregnant controls, gastric emptying was markedly delayed in women receiving opioid analgesia during labor when compared with laboring controls who had received nonopioid analgesia. The opioid inhibitory effect was not reversed with metoclopramide. Measurements in patients receiving opioid analgesia 25 days after delivery were similar to controls. OSullivan et al. (17) also demonstrated delayed gastric emptying in patients receiving parenteral opioid analgesia. This epigastric impedance study demonstrated delays occurring 60 min after delivery when patients had received meperidine and promethazine during labor. Although other studies have demonstrated delays in gastric emptying produced by epidural opioids during labor, these reports have not included postpartum data (18,19). Collectively, these studies confirm that additional delays in gastric emptying occur after intrapartum epidural or parenteral opioid administration. Unfortunately, postpartum gastric emptying studies after opioid administration are lacking. Whether intrapartum opioids contribute significantly to delayed gastric emptying within 8 h of delivery is unknown.
Several gastric-emptying related factors should influence the decision to proceed with general anesthesia for postpartum tubal ligation within 8 h of delivery. Although it is unclear when the risk of postpartum aspiration is reduced, solid food intake and intrapartum opioid administration may contribute to delays in postpartum gastric emptying. When patients refuse regional anesthesia and have a history of recent solid food intake or intrapartum opioids, sterilization may be delayed to improve alterations in gastric emptying. For aspiration prophylaxis, a nonparticulate antacid is frequently administered before postpartum tubal ligation (21). In patients with additional aspiration risk, e.g., diabetes or obesity, multi-drug prophylaxis with an H2-blocking drug and/or metoclopramide may be advantageous.
 |
Which Regional Anesthetic Is Best for Postpartum Tubal Ligation?
|
|---|
Choice of neuraxial anesthesia for postpartum tubal ligation will depend on patient preference, existence of a functional epidural catheter, and the interval from delivery to tubal sterilization. Some epidural catheters that have provided adequate analgesia for labor may prove inadequate for surgical procedures. Although a functioning epidural avoids general anesthesia, regional anesthetic failure within 8 h of delivery could result in general anesthesia when the risk of aspiration may remain at the levels seen during labor.
Epidural Reactivation
Several factors contribute to satisfactory epidural anesthesia for tubal ligation. The interval from delivery to tubal ligation is one factor affecting success of epidural reactivation. Viscomi and Rathmell (22) evaluated epidural reactivation after delivery and reported that 93% of catheters were functional for postpartum tubal ligation within 14 h of delivery. Only 68% of catheters, however, were functional during the next 4 h after delivery. These authors noted that additional time was also required in unsuccessful reactivations. Vincent and Reid (23) also evaluated success rates of epidural reactivation after delivery for tubal sterilization. Although the distance that the catheter was inserted into epidural space was not mentioned, a 100% success rate was reported within 8 h of delivery and a 55% success rate after 8 h. More recently, Goodman and Dumas (24) retrospectively examined the success rate of epidural reactivation based on the following delivery and tubal sterilization intervals: 1) <8 h; 2) 8 to <16 h; 3) 16 to <24 h; and 4) 24 h or more. Overall, 92% (129/140) of reactivations were successful with 80% successful reactivations occurring more than 24 h after delivery. Because studies of epidural reactivation have produced conflicting results, it is difficult to predict an interval that will guarantee successful reactivation. The Practice Guidelines for Obstetric Anesthesia suggest that epidural catheters placed for labor may be more likely to fail with longer postdelivery intervals (2). When postpartum tubal ligation is anticipated within several hours after delivery and the epidural catheter provided adequate labor analgesia, it is reasonable to attempt epidural reactivation. If the procedure is delayed beyond that time, epidural reactivation may fail. Although epidural replacement is one alternative when delivery to tubal ligation interval is prolonged, subarachnoid anesthesia may be a better alternative for such a time-limited procedure.
Technical Factors Influencing Successful Epidural Anesthesia for Tubal Ligation
In addition to the interval from delivery to tubal ligation, other technical factors affect the likelihood of successful epidural anesthesia. Epidural catheter movement can result in inadequate analgesia. An important factor affecting catheter dislodgement and satisfactory analgesia may be depth of original epidural catheter insertion. To minimize the risk of catheter dislodgement, especially in obese parturients, Hamilton et al. (25) suggested that patients assume an upright or lateral position from a flexed position before securing the catheter to the skin. These authors also recommended catheter insertion depths of at least 4 cm (25). DAngelo et al. (26) evaluated distance of single-port epidural catheters inserted into the epidural space in parturients and determined that catheters inserted 6 cm into the epidural space were more likely to remain functional when prolonged or cesarean delivery was anticipated compared with catheters inserted 24 cm into the epidural space, which often required replacement. In a prospective, randomized, double-blinded study, Beilen et al. (27) determined 5 cm epidural insertion depth was associated with the highest incidence of satisfactory analgesia in laboring women. Comparisons of single versus multi-orifice epidural catheters revealed that multi-orifice catheters provided superior analgesia and required less manipulation (28). Although the "walking epidural" and postpartum ambulation could effect the incidence of dislodgement and success of epidural reactivation, ambulation has not been evaluated as a causative factor for catheter dislodgement in postpartum patients.
Inadequate Epidural Anesthesia After Reactivation
Despite the best attempts, some patients with a preexisting epidural will require supplementation with local anesthetic infiltration, spinal anesthesia, a new epidural, or general anesthesia. When large amounts of local anesthetic have been administered epidurally and reactivation fails, spinal anesthesia is an alternative, although the safety of this is uncertain. Reports of high or total spinal anesthesia occurring when spinal anesthetics were administered within 30 min of large volumes of epidurally administered local anesthetics or saline have been published (2932). These results can be explained by several possible mechanisms. Beck and Griffiths (30) suggested that extensive blockade may result from a physical effect of the fluid volume in the epidural space. In that case report, the authors observed total spinal anesthesia when 2.5 mL hyperbaric 0.5% bupivacaine was injected after 15 mL of epidurally administered saline before cesarean delivery. Alternatively, subarachnoid passage of epidurally administered local anesthetics could occur, producing higher levels of spinal anesthesia. In addition, diffusion of epidurally administered local anesthetics to the subarachnoid space may augment subsequent spinal anesthetics. Although the appropriate spinal anesthetic dose is not predictable after unsuccessful attempts at epidural reactivation, reducing the subsequent spinal anesthetic dose or allowing sufficient time for resolution of the epidural blockade can result in satisfactory anesthesia without complications. Because caution should be used when administering spinal anesthesia after recent epidural reactivation, alternatives include: 1) repeating the epidural anesthetic with a short-acting local anesthetic (e.g., 3% 2-chloroprocaine); 2) allowing the block to recede and administering a single-injection spinal anesthetic; and 3) general anesthesia.
Careful bilateral sensory testing before surgical incision will aid in preventing intraoperative epidural failure. Occasionally, epidural catheters are adequate for labor but prove inadequate intraoperatively after reactivation. Because there are reports of successful tubal ligation performed under local anesthesia, patients with marginal epidural anesthesia may benefit from intraoperative subcutaneous and intraperitoneal local anesthetic supplementation (33). If the addition of sedation and local anesthetic injections are inadequate, conversion to general anesthesia may be necessary.
 |
Spinal Anesthesia for Tubal Ligation
|
|---|
Spinal anesthesia is often suggested to patients for postpartum tubal ligation. Spinal and epidural anesthetic requirements decrease during pregnancy and return to nonpregnant levels 3648 h after delivery (34). Abouleish (34) prospectively compared bupivacaine spinal anesthetic requirements in pregnant and postpartum patients. In postpartum patients, a 30% increase in spinal anesthetic requirements occurred 824 h after delivery (35). Because tubal sterilization procedures are of limited duration, short-acting spinal anesthetics are preferred. Hyperbaric lidocaine has often been used for postpartum tubal procedures. Although case reports of transient radicular irritation (3638) have raised questions of neurotoxicity, possibly related to hyperbaric spinal lidocaine, transient radicular irritation has not been reported in pregnant patients. Despite the Food and Drug Administrations alterations of the package insert recommending dilution of hyperbaric 5% lidocaine with cerebral spinal fluid or saline, several studies (3941) report the incidence of transient neurologic symptoms is not decreased by reducing the concentration of lidocaine from 5% to 2%. Although permanent neurologic damage has not been reported from single-injections of hyperbaric 5% lidocaine, practitioners will often choose other spinal anesthetics. One alternative to hyperbaric lidocaine might be subarachnoid meperidine. Because meperidine has local anesthetic properties and provides an agonist-mediated analgesia, it has been evaluated in postpartum patients requesting tubal ligation. Norris et al. (41) randomized 20 unpremedicated women to receive subarachnoid meperidine versus hyperbaric lidocaine for postpartum tubal ligation and reported that, although patients receiving subarachnoid meperidine experienced more pruritus, they also experienced better postoperative analgesia. Patients expressed equal satisfaction with both drugs, and there was a 10% incidence of spinal failure in each group. Although bupivacaine (hyperbaric or isobaric) is another alternative used by some anesthesiologists, prolonged recovery times limit its use for these time-limited procedures.
 |
Local Anesthesia for Tubal Ligation
|
|---|
Although tubal ligation can be performed under local anesthesia with sedation (33), the Practice Guidelines for Obstetric Anesthesia questions the effectiveness of this technique (2).
Recently, the American Society of Anesthesiologists Task Force on Obstetric Anesthesia published Practice Guidelines for Obstetric Anesthesia, including recommendations for postpartum tubal ligation. In many patients, tubal ligation can be performed safely within 8 h of delivery (2). In high-risk patients, the medical risks of a subsequent pregnancy must be weighed against those of postpartum sterilization. The Practice Guidelines for Obstetric Anesthesia suggests that epidural, spinal, or general anesthesia can be provided without affecting maternal complications (2). Although the true anesthetic risk of postpartum tubal ligation is unknown, there are few reports of complications. Because solid food intake and administration of parenteral or epidural opioids may contribute to delays in postpartum gastric emptying, the decision to provide general anesthesia for postpartum sterilization within several hours of delivery should be considered carefully. Although there is insufficient literature to evaluate the comparative benefits of each anesthetic technique, the timing of the procedure and the decision to use a particular anesthetic technique (i.e., regional versus general) should be individualized, based on anesthetic and/or obstetric risk factors and patient preference (2).
 |
Acknowledgments
|
|---|
The authors thank John H. Tinker, MD, for his editorial assistance.
 |
References
|
|---|
-
Piccino LJ, Mosher WD. Trends in contraceptive use in the United States: 19821995. Fam Plann Perspect 1998;30:410,46.
-
Practice Guidelines for Obstetrical Anesthesia: a report by the American Society of Anesthesiologists Task Force on Obstetrical Anesthesia. Anesthesiology 1999;90:60011.[Web of Science][Medline]
-
Vincent RD Jr, Martin RW. Postpartum tubal ligation after pregnancy complicated by preeclampsia or gestational hypertension. Obstet Gynecol 1996;88:11922.[Web of Science][Medline]
-
American College of Obstetricians and Gynecologists, Committee on Obstetric Practice. Committee opinion. No. 105, March 1992.
-
Hawkins JL, Koonin LM, Palmer SK, Gibbs CP. Anesthesia-related deaths during obstetric delivery in the United States, 19791990. Anesthesiology 1997;86:27784.[Web of Science][Medline]
-
Peterson HB, DeStefano F, Gubin GL, et al. Deaths attributable to tubal sterilization in the United States, 1977 to 1981. Gynecol 1983;146:1316.
-
Peterson HB, Destefano F, Greenspan JR, Ory HW. Mortality risk associated with tubal sterilization in United States hospitals. Am J Obstet Gynecol 1982;143:1259.[Web of Science][Medline]
-
Endler GC, Mariona FG, Sokol RJ, Stevenson LB. Anesthesia-related maternal mortality in Michigan, 1972 to 1984. Am J Obstet Gynecol 1988;159:18793.[Web of Science][Medline]
-
Rubin GL, Peterson HB, Rochat RW, et al. Maternal death after cesarean section in Georgia. Am J Obstet Gynecol 1981;139:6815.[Web of Science][Medline]
-
Syverson CJ, Chavkin W, Atrash HK, et al. Pregnancy-related mortality in New York City, 19801984: causes of death and associated risk factors. Gynecol 1991;164:6038.
-
Lyons G. Failed intubation: six years experience in a teaching maternity unit. Anaesthesia 1985;40:75962.[Web of Science][Medline]
-
Rocke DA, Murray WB, Rout CC, Gouws E. Relative risk analysis of factors associated with difficult intubation in obstetric anesthesia. Anesthesiology 1992;77:6773.[Web of Science][Medline]
-
Mackenzie AI. Laryngeal oedema complicating obstetric anaesthesia [letter]. Anaesthesia 1978;33:2717.[Web of Science][Medline]
-
Carp H, Jayaram A, Stoll M. Ultrasound examination of the stomach contents of parturients. Analg 1992;74:6837.[Abstract/Free Full Text]
-
Jayaram A, Bowen MP, Deshpande S, Carp HM. Ultrasound examination of the stomach contents of women in the postpartum period. Anesth Analg 1997;84:5226.[Abstract]
-
Nimmo WS, Wilson J, Prescott LF. Narcotic analgesics and delayed gastric emptying during labor. Lancet 1975;1:8903.[Web of Science][Medline]
-
OSullivan GM, Sutton AJ, Thompson SA, et al. Noninvasive measurement of gastric emptying in obstetric patients. Anesth Analg 1987;66:50511.[Abstract/Free Full Text]
-
Wright PMC, Allen RW, Moore J, Donnelly JP. Gastric emptying during lumbar extradural analgesia in labour: effect of fentanyl supplementation. Br J Anaesth 1992;68:24851.[Abstract/Free Full Text]
-
Ewah B, Yau K, King M, et al. Effect of epidural opioids on gastric emptying in labour. Int J Obstet Anesth 1993;2:1258.
-
Smout A, Horowitz M, Armstrong D. Methods to study gastric emptying. Dig Dis Sci 1994;39:130S2S.[Medline]
-
Hawkins JL. Postpartum tubal sterilization. In: Chestnut DH, ed. Obstetric anesthesia: principles and practice. St Louis:Mosby, 1994:44355.
-
Viscomi CM, Rathmell JP. Labor epidural catheter reactivation or spinal anesthesia for delayed postpartum tubal ligation: a cost comparison. J Clin Anesth 1995;7:3803.[Web of Science][Medline]
-
Vincent RD, Reid RW. Epidural anesthesia for postpartum tubal ligation using epidural catheters placed during labor. J Clin Anesth 1993;5:28991.[Web of Science][Medline]
-
Goodman EJ, Dumas SD. The rate of successful reactivation of labor epidural catheters for postpartum tubal ligation surgery. Reg Anesth Pain Med 1998;23:25861.[Web of Science][Medline]
-
Hamilton CL, Riley ET, Cohen SE. Changes in the position of epidural catheters associated with patient movement. Anesthesiology 1997;86:77884.[Web of Science][Medline]
-
DAngelo R, Berkebile BL, Gerancher JC. Prospective examination of epidural catheter insertion. Anesthesiology 1996;84:8893.[Web of Science][Medline]
-
Beilen Y, Bernstein HH, Zucker-Pinchoff B. The optimal distance that a multiorifice epidural catheter should be threaded into the epidural space. Anesth Analg 1995;81:3014.[Abstract]
-
DAngelo R, Foss ML, Livesay CH. A comparison of multiport and uniport epidural catheters in laboring patients. Anesth Analg 1996;84:12769.[Abstract]
-
Mets B, Broccoli E, Brown AR. Is spinal anesthesia after failed epidural anesthesia contraindicated for cesarean section? Anesth Analg 1993;77:62931.[Free Full Text]
-
Beck GN, Griffiths AG. Failed extradural anaesthesia for Caesarean section: complication of subsequent spinal block. Anaesthesia 1992;47:6902.[Web of Science][Medline]
-
Furst SR, Reisner LS. Risk of high spinal anesthesia following failed epidural block for cesarean delivery. J Clin Anesth 1995;7:714.[Web of Science][Medline]
-
Cruikshank DP, Laube DW, DeBacker LJ. Intraperitoneal lidocaine anesthesia for postpartum tubal ligation. Obstet Gynecol 1973;42:12730.[Web of Science][Medline]
-
Assali NS, Prytowsky H. Studies on autonomic blockade. II. Observations on the nature of blood pressure fall with high selective spinal anesthesia in pregnant women. J Clin Invest 1950;20:136775.
-
Abouleish EI. Postpartum tubal ligation requires more bupivacaine for spinal anesthesia than does caesarean section. Anesth Analg 1986;65:897900.[Abstract/Free Full Text]
-
Schneider M, Ettlin T, Kaufmann M, et al. Transient neurologic toxicity after hyperbaric subarachnoid anesthesia with 5% lidocaine. Anesth Analg 1993;76:11547.[Free Full Text]
-
Snyder R, Hui G, Flugstad P, Viarengo C. More cases of possible neurologic toxicity associated with single subarachnoid injections of 5% hyperbaric lidocaine [letter]. Analg 1994;78:411.[Web of Science][Medline]
-
Sjoestroem S, Blaess J. Severe pain in both legs after spinal anaesthesia with hyperbaric 5% lignocaine solution. Anaesthesia 1994;49:7002.[Web of Science][Medline]
-
Hampl KF, Schneider MC, Pargger H, et al. A similar incidence of transient neurologic symptoms after spinal anesthesia with 2% and 5% lidocaine. Anesth Analg 1996;83:10514.[Abstract]
-
Pollack JE, Neal JM, Stephenson CA, Wiley CE. Prospective study of the incidence of transient radicular irritation in patients undergoing spinal anesthesia. Anesthesiology 1996;84:13617.[Web of Science][Medline]
-
Freedman JM, Li DK, Drasner K, et al. Transient neurologic symptoms after spinal anesthesia: an epidemiologic study of 1,863 patients. Anesthesiology 1998;89:63341.[Web of Science][Medline]
-
Norris MC, Honet JE, Leighton BL, Arkoosh VA. A comparison of meperidine and lidocaine for spinal anesthesia for postpartum tubal ligation. Reg Anesth 1996;21:848.
Accepted for publication July 6, 1999.
|