Efedrina versus fenilefrina: prevenção de hipotensão arterial durante anestesia raquídea para cesariana e efeitos sobre o feto / Efedrina versus fenilefrina: prevención de hipotensión arterial durante anestesia raquidea para cesárea y efectos sobre el feto / Ephedrine versus phenylephrine: prevention of hypotension during spinal block for cesarean section and effects on the fetus

JUSTIFICATIVA E OBJETIVOS: A hipotensão arterial durante a anestesia raquídea para cesariana deve-se ao bloqueio simpático e compressão aorto-cava pelo útero e pode ocasionar efeitos deletérios para o feto e a mãe. A efedrina e fenilefrina melhoram o retorno venoso após bloqueio simpático durante anestesia raquídea. O objetivo deste estudo foi comparar a eficácia da efedrina e da fenilefrina em prevenir e tratar a hipotensão arterial materna durante anestesia raquídea e avaliar seus efeitos colaterais e alterações fetais. MÉTODO: Sessenta pacientes, submetidas à anestesia raquídea com bupivacaína e sufentanil para cesariana, foram divididas aleatoriamente em dois grupos para receber, profilaticamente, efedrina (Grupo E, n = 30, dose = 10 mg) ou fenilefrina (Grupo F, n = 30, dose = 80 µg). Hipotensão arterial (pressão arterial menor ou igual a 80 por cento da medida basal) foi tratada com bolus de vasoconstritor com 50 por cento da dose inicial. Foram avaliados: incidência de hipotensão arterial, hipertensão arterial reativa, bradicardia e vômitos, escore de Apgar no primeiro e quinto minutos e gasometria do cordão umbilical. RESULTADOS: A dose média de efedrina foi 14,8 ± 3,8 mg e 186,7 ± 52,9 µg de fenilefrina. Os grupos foram semelhantes quanto aos parâmetros demográficos e incidência de vômitos, bradicardia e hipertensão arterial reativa. A incidência de hipotensão arterial foi de 70 por cento no Grupo E e 93 por cento no Grupo F (p < 0,05). O pH arterial médio do cordão umbilical e o escore de Apgar no primeiro minuto foram menores no grupo E (p < 0,05). Não houve diferença no escore do quito minuto. CONCLUSÕES: A efedrina foi mais eficiente que fenilefrina na prevenção de hipotensão arterial. Ambos os fármacos apresentaram incidência semelhante de efeitos colaterais. As repercussões fetais foram menos freqüentes com o uso da fenilefrina e apenas transitórias com a utilização da efedrina.

JUSTIFICATIVA Y OBJETIVOS: La hipotensión arterial durante la anestesia raquídea para cesárea se debe al bloqueo simpático y a la compresión aortocava por el útero y puede ocasionar efectos malignos para el feto y su madre. La efedrina y fenilefrina mejoran el retorno venoso después del bloqueo simpático durante la anestesia raquídea. El objetivo de este estudio fue comparar la eficacia de la efedrina y de la fenilefrina en prevenir y tratar la hipotensión arterial materna durante la anestesia raquídea y evaluar así sus efectos colaterales y las alteraciones fetales. MÉTODO: Sesenta pacientes, sometidas a la anestesia raquídea con bupivacaína y sufentanil para cesárea, se dividieron aleatoriamente en dos grupos para recibir, profilácticamente, efedrina (Grupo E, n = 30, dosis = 10mg) o fenilefrina (Grupo F, n = 30, dosis = 80 µg). Hipotensión arterial (presión arterial menor o igual a un 80 por ciento de la medida basal) fue tratada con bolo de vasoconstrictor con un 50 por ciento de la dosis inicial. Se evaluaron: incidencia de hipotensión arterial, hipertensión arterial reactiva, bradicardia y vómitos, puntuación de Apgar en el 1º y 5º minutos y gasometría del cordón umbilical. RESULTADOS: La dosis promedio de efedrina fue 14,8 mg (± 3,8) y 186,7 µg (± 52,9) de fenilefrina. Los grupos fueron similares en cuanto a los parámetros demográficos y a la incidencia de vómitos, bradicardia e hipertensión arterial reactiva. La incidencia de hipotensión arterial fue de un 70 por ciento en el Grupo E y un 93 por ciento en el Grupo F (p < 0,05). El pH arterial promedio del cordón umbilical y el puntaje de Apgar en el 1º minuto fueron menores en el grupo E (p < 0,05). No se registró diferencia en el puntaje del 5º minuto. CONCLUSIONES: La efedrina fue más efectiva que la fenilefrina en la prevención de la hipotensión arterial. Los dos fármacos presentaron una incidencia similar de efectos colaterales. Las repercusiones fetales fueron menos frecuentes...

BACKGROUND AND OBJECTIVES: Hypotension during spinal block for cesarean section is secondary to the sympathetic blockade and aorto-caval compression by the uterus and it can be deleterious to both the fetus and the mother. Ephedrine and phenylephrine improve venous return after sympathetic blockade during the spinal block. The objective of this study was to compare the efficacy of ephedrine and phenylephrine in the prevention and treatment of maternal hypotension during spinal block and to evaluate their side effects and fetal changes. METHODS: Sixty patients undergoing spinal block with bupivacaine and sufentanil for cesarean section were randomly divided in two groups to receive prophylactic ephedrine (Group E, n = 30, dose = 10 mg) or phenylephrine (Group P, n = 30, dose = 80 µg). Hypotension (blood pressure equal or lower than 80 percent of baseline values) was treated with bolus administration of the vasoconstrictor at 50 percent of the initial dose. The incidence of hypotension, reactive hypertension, bradycardia, and vomiting, and Apgar scores on the 1st and 5th minutes, and blood gases of the umbilical cord blood were evaluated. RESULTS: The mean dose of ephedrine used was 14.8 ± 3.8 mg and of phenylephrine was 186.7 ± 52.9 µg. Demographic parameters and the incidence of vomiting, bradycardia, and reactive hypertension were similar in both groups. Hypotension had an incidence of 70 percent in Group E and 93 percent in Group P (p < 0.05). The mean arterial pH of the umbilical cord blood and the Apgar score in the 1st minute were lower in Group E (p < 0.05). Differences in the Apgar score in the 5th minute were not observed. CONCLUSIONS: Ephedrine was more effective than phenylephrine in the prevention of hypotension. Both drugs had similar incidence of side effects. Fetal repercussions were less frequent with phenylephrine and were transitory with the use of ephedrine.

Is It Mandatory to Incise Immediately after Intubation in Cesarean Section? / 대한마취과학회지

BACKGROUND: If general anesthesia is used for cesarean section, important considerations include minimizing the duration of general anesthesia. One may think that skin incision should be started immediately after endotracheal intubation. If so, intra-operative awareness and perception of pain may occur due to light anesthesia. Allowing skin incision to be started 5 min after intubaton while administering 50% nitrous oxide and isoflurane 0.75%, we investigated the changes of BIS (bispectral index), and Apgar scores. METHODS: The investigation was carried out on 33 full-term ASA 1 or 2 patients underwent elective cesarean section under general anesthesia. If any fetal abnormalities were found, we excluded those cases. Premedication was omitted. After rapid sequence induction with sodium thiopental 4 mg/kg, succinylcholine 1 mg/kg, we made skin incision immediately after intubation in control group (n = 18) and 5 min after intubation in experimental group while administering 50% nitrous oxide and isoflurane 0.75%. Muscle relaxation was maintained with intravenous administration of atracurium 0.5 mg/kg. We measured BIS, mean arterial pressure (MAP), heart rate in 1 min interval from preinduction period to delivery and recorded Apgar scores 1 and 5 min after delivery, skin incision to delivery time and uterine incision to delivery time. And we counted the number of patients whose BIS values had been below 60 and 70 from skin incision to delivery in each group. RESULT: Apgar scores recorded 1 and 5 min after delivery did not show significant differences between control and experimental group. During the periods of abdominal wall traction, uterine incision and delivery, BIS values of experimental group were significantly lower than control group and moreover, tended to remain below 60 while those of control group during the same periods tended to be above 60 (P < 0.05). The number of patients of experimental group, whose BIS values had been below 60 from skin incision to delivery, was twice as much as that of control group (P < 0.05), but in case of BIS value below 70, there was no significant difference between control and experimental group. During the periods of skin incision and abdominal wall traction, the MAP's of experimental group were significantly lower than control group (P < 0.05). In cases of heart rate, skin incision to delivery time and uterine incision to delivery time, there were no significant differences between control and experimental group. CONCLUSION: Allowing the skin incision to be started 5 min after intubation while administering 50% nitrous oxide and isoflurane 0.75%, BIS values remained below 60 from abdominal wall traction to delivery, and anesthetics-induced fetal depression did not occur.

The Effect of Spinal Anesthesia for Cesarean Section on Hemodynamics in Patients with Severe Preeclampsia / 대한마취과학회지

BACKGROUND: Epidural anesthesia is thought to be relatively indicated for cesarean section in patients with severe preeclampsia. In contrast, avoidance of spinal anesthesia is recommended, postulating excessive hypotensive risks. In addition, general anesthesia is often avoided in this population because malignant hypertension following tracheal intubation is common and risks for difficult airway management are excessive. METHODS: In this study, we compared hemodynamic changes in patients with severe preeclampsia and normal pregnant women during spinal anesthesia for elective cesarean section. Spinal anesthesia was performed with 10 mg of 0.5% heavy bupivacaine mixed with 25 microgram fentanyl in 18 patients with severe preeclampsia and 17 normal pregnant women. We compared MAP, CI, and SVRI changes before and after spinal anesthesia. RESULTS: MAP responses following induction of spinal anesthesia for elective cesarean section in patients with severe preeclampsia and normal pregnant women showed a statistically significant decrease from 2 min after spinal anesthesia. CI responses following induction of spinal anesthesia in patients with severe preeclampsia showed a statistically significant increase from 8 min after and normal pregnant women also showed a statistically significant increase from 4 min after spinal anesthesia. SVRI responses from induction of spinal anesthesia in patients with severe preeclampsia and normal pregnant women showed a statistically significant decrease from 2 min after spinal anesthesia. Incidence of hypotension before delivery and used total dose of ephedrine during operation were statically insignificant between severe preeclamptic and normal pregnant women. CONCLUSIONS: We conclude that changes of MAP, CI and SVRI following spinal anesthesia for elective cesarean section in the severely preeclamptic and normal pregnant women are clinically similar. We suggest that spinal anesthesia for cesarean section is not contraindicated in the severely preeclamptic patient.

Comparison of Intrathecal Meperidine, Fentanyl, or Placebo Added to 0.5% Hyperbaric Bupivacaine for Cesarean Section / 대한마취과학회지

BACKGROUND: The addition of various opioids to 0.5% hyperbaric bupivacaine intrathecally seems to potentiate analgesic effects of bupivacaine and to prolong the duration of analgesia. We compared the effect of intrathecal meperidine 0.25 mg/kg and 0.5 mg/kg, fentanyl 0.15 microgram/kg, and placebo when administered together with 0.5% hyperbaric bupivacaine 9 mg for cesarean section. METHODS: Forty-four healthy term parturients were randomly allocated (n = 11 per group) to receive the test solution (1 ml) containing preservative-free normal saline (control group), fentanyl 0.15 microgram/kg, meperidine 0.25 mg/kg, or meperidine 0.5 mg/kg intrathecally, immediately followed by the injection of 0.5% hyperbaric bupivacaine 9 mg. We observed the effective postoperative analgesic duration (time to VAS > or = 4), quality of anesthesia and side effects. RESULTS: The effective postoperative analgesic duration significantly increased in the groups receiving opioid compared with the control group (P < 0.05); control group 101.4 +/- 28.6 min; fentanyl group 192.3 +/- 29.2 min; meperidine 0.25 mg/kg group 208.8 +/- 21.7 min; meperidine 0.5 mg/kg group 289.8 53.6 min (data expressed as mean +/- SD). The quality of anesthesia was excellent in 100% of the meperidine group but in 82% of the fentanyl group and 91% of the control group. The incidence of nausea and vomiting were higher in the meperidine 0.5 mg/kg group (73%) than in the remaining groups (P < 0.05). CONCLUSIONS: The addition of fentanyl 0.15 microgram/kg or meperidine 0.25 mg/kg to 0.5% hyperbaric bupivacaine 9 mg for spinal anesthesia improves intraoperative analgesia and provides analgesia into the immediate postoperative period with no adverse effects on mother or neonate.

The Effect of Prior Dural Puncture with a 27G Spinal Needle on Epidural Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: If started with segmental block, epidural anesthesia appears to have an inadequate sacral block in the early part of cesarean deliveries. A dural puncture using the combined spinal-epidural technique making an early sacral blockade might be a solution. METHODS: A prospective, randomized, double-blinded study was performed on forty patients who were divided into two groups (C, DP; n = 20, each). An epidural infusion of 25 ml of 2% lidocaine with epinephrine was given to the group C. A dural puncture with a 27G Whitacre needle was done before the epidural infusion in the group DP. Two-way sensory levels were checked for 15 min, just before the operation. The side effects and recovery variables were also compared between the groups. RESULTS: Initial wider cephalic block (P = 0.038, 0 min) followed by more caudal block (P = 0.023, 0.013; 5, 10 min after the completion of the epidural infusion, respectively) occurred in the DP group. After 10 min, there were no differences in both block levels. The number of dermatomes blocked was bigger in the DP group at 10 min after. Fewer patients in the DP group had nausea and/or vomiting (P = 0.044). CONCLUSIONS: Early spread of the sensory blockade, initial cephalic and then caudal, was due to the dural puncture by a 27G needle. This fast onset could make the parturients more comfortable in the early part of cesarean sections.

The Effects of Epidural "Top-up" on Spinal Block during Combined Spinal Epidural Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: Epidural "top-up" has been known to enhance spinal anesthesia in combined spinal-epidural anesthesia. Saline and local anesthetics were reported to have a volume effect when infused as epidural "top-up". In cesarean deliveries where high sensory block has been achieved using a combined spinal-epidural technique, we evaluated the effects of epidural "top-up" on the underlying spinal block. METHODS: Sixty-six parturients were allocated randomly into group C (control, n = 21), S (saline, n = 21), or B (bupivacaine, n = 24). Ten minutes after they received 8 mg of 0.5% hyperbaric bupivacaine intrathecally, nothing, 10 ml saline, or 10 ml of 0.25% bupivacaine were infused, respectively. The sensory level at 10 min, the maximal level and the time to reach it, and degrees of motor block and muscle relaxation were compared. We also investigated intraoperative side effects and postoperative findings in the PACU. RESULTS: There were significant changes in sensory level after epidural top-ups in the group S and B, but no differences in maximal height of sensory block and degree of muscle relaxation among the groups. Intraoperative pain was complained in fewer patients in the group B. Times to sensory and motor recovery were longer in patients of the group B. CONCLUSIONS: Eight milligrams of hyperbaric bupivacaine using a combined spinal-epidural technique was not sufficient for cesarean section. Epidural saline top-up showed volume effect, which didn't improve the spinal block. Epidural "top-up" of 0.25% 10 ml bupivacaine enhanced the spinal block and sustained the block postoperatively.

Adequate Target Concentration of Propofol and Fentanyl for Total Intravenous Anesthesia by Target-controlled Infusion during Cesarean Section / 대한마취과학회지

BACKGROUND: Propofol has been used for the induction and maintenance of obstetric anesthesia for its potential benefit of rapid recovery and less post-anesthetic complications. In order to determine the safe application of target-controlled infusion of propofol and fentanyl during Cesarean section under general anesthesia, we have investigated the adequate target concentrations of each drug using the bispectral index and hemodynamic parameters. METHODS: Ninety-two pregnant women who received Cesarean section under general anesthesia were enrolled in this study. After preoxygenation, anesthesia was induced with thiopental 4 mg/kg and succinylcholine 1 mg/kg, and intubation was done. Vecuronium 0.1mg/kg I.V. was applied for muscle relaxation, and mechanical ventilation was maintained with N2O/O2 (2 L/2 L)-enflurane. EtCO2 was maintained between 30 35 mmHg. After delivery of the fetus, propofol and fentanyl was infused by a computer-assisted continuous infusion system with air/O2 (2 L/2 L). The bispectral index was monitored perioperatively. This study proceeded in three stages. In the first stage, thirty women were studied for titration of the target effect-site concentration of propofol that could maintain a bispectral index between 40 60 while maintaining the target concentration of fentanyl at 1.5 ng/ml. In the second stage, forty-two women were randomly assigned into the four different groups (F25, F50, F75, F100) at target fentanyl concentrations of fentanyl of 0.25, 0.50, 0.75 and 1.0 ng/ml for each group respectively. The adequate target concentration of fentanyl was titrated. In the third stage, twenty women were studied for assessment of the adequacy of target concentrations of propofol and fentanyl prospectively. RESULTS: The target effect-site concentrations (Ce, 95% confidence interval) that could maintain 50% and 95% of patients hemodynamically stable with the bispectral index within 40-60 were 2.41 (2.27-2.55) microgram/ml and 3.15 (2.95-3.50) microgram/ml for propofol, 0.32 (0.13-0.46) ng/ml and 0.84 (0.66-1.29) ng/ml for fentanyl. The pre-anesthetic bispectral index was 97.1+/-1.2 and it decreased maximally to 39.5+/-6.47 after thiopental injection and increased maximally to 83.6+/-6.3 before delivery and it was 80.6+/-6.9 for eye-open to verbal command during recovery. CONCLUSIONS: The adequate target effect-site concentrations of propofol and fentanyl for the maintenance of total intravenous anesthesia during Cesarean section were determined and these concentrations were validated prospectively.

The Effect of Different Route of Preanesthetic Ranitidine on Gastric Acidity in Patients Undergoing Elective Cesarean Section / 대한마취과학회지

BACKGROUND: Aspiration of gastric contents is an ever -present risk in the use of general anesthesia, particularly in emergency and obstetric situations, and morbidity and mortality associated with this complication increases with the volume and acidity of the aspirate. Since direct inhibition of acid secretion may be a preferable method, we studied the effectiveness of ranitidine in increasing gastric pH. METHODS: Sixty patients scheduled for elective cesarean section under general anesthesia before midday were randomly divided into three groups. The control group (n=20) did not received preanesthetic ranitidine. Group I (n=20) received a slow intravenous injection of 50 mg ranitidine, one hour before surgery. Group II (n=20) received 150 mg ranitidine orally, both the night before surgery and the morning of surgery. RESULTS: Compared with the control group, the mean gastric pH increased significantly in group I and II (P<0.05). There was no significant difference of gastric pH between group I and II. CONCLUSIONS: The results of this study indicate that ranitidine is a useful agent in increasing the gastric pH in women undergoing elective cesarean section. Ranitidine administered intravenously and orally were equally effective means in increasing the gastric pH.

Comparison of Combined Spinal Epidural Anesthesia and Epidural Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: Epidural anesthesia (EA) has become most popular for cesarean section, but has some drawbacks such as incomplete block, inadequate muscle relaxation and delayed onset. Combined spinal epidural anesthesia (CSEA) has gained an increasing interest as it combines a reliability of the spinal block and the flexibility of an epidural block. We investigated the efficacy of CSEA which combines main spinal and supporting epidural anesthesia, comparing with pH adjusted EA, for cesarean section. METHODS: Sixty four pregnant women at full term were divided into two groups. Group 1 (n=32) received CSEA with 1.5~1.6 ml of 0.5% hyperbaric bupivacaine intrathecally, followed 10 minutes after by 10 ml of 0.25% plain bupivacaine through the epidural catheter. Group 2 (n=32) received EA with 20~25 ml of 2% lidocaine which was added 0.1 ml of 0.1% epinephrine, 100 microgram of fentanyl and 1.5 ml of 8.4% sodium bicarbonate. The quality and side effects of surgical anesthesia, neonatal state and postoperative course were compared between two groups. RESULTS: While 22% (7 cases) of Group 2 complained of intraoperative pain but none of Group 1 did (p=0.011). Muscle relaxation and motor block were much better in group 1 (p<0.001 and p=0.011 each). Significantly more women in group 2 had shivering (p=0.001) and they also had nausea and vomiting more, though that difference is not significant. Not only time to T4 (9.7 vs. 8.3 min., mean, p<0.001), but also stay at PACU, recovery of sensory and motor block and start of postoperative pain were all significantly shorter in Group 1. None of both groups had post-dural puncture headache (PDPH). CONCLUSIONS: We can conclude that CSEA, when combining main spinal and supporting epidural anesthesia, has greater efficacy and less side effects for cesarean section than pH adjusted EA.

The Effect of Anesthesia with Propofol-N2O on Neonate and Maternal Awareness during Cesarean Section / 대한마취과학회지

BACKGROUND: In anesthesia for cesarean section, there is an increased incidence of maternal awareness because a light plane of general anesthesia is chosen for fetal safety and rapid recovery. Propofol may be the choice if smooth induction and rapid maternal recovery are desired. Authors tried to know that propofol has properties which suggest that it might be useful alternative to thiopental and enflurane. METHODS: Forty patients in ASA class I or II scheduled for cesarean section were allocated randomly to either propofol (n=20) (P) or thiopental-enflurane (n=20) (T-E) group. Anesthesia was induced with propofol 2 mg/kg IV and maintained by continuous infusion of propofol 8 mg/kg/hr in P group and was induced with thiopental 4 mg/kg IV and maintained by inhalation of 1 vol% enflurane in T-E group. All patients received vecuronium 0.1 mg/kg and 50% N2O-O2. Blood pressure, heart rate, Apgar score, umbilical arterial blood gas analysis and the incidence of maternal awareness using the isolated forearm technique (IFT) were evaluated. RESULTS: Diastolic pressure was decreased in P group than T-E group at 10 min after delivery. Heart rate was increased in P group than T-E group at immediate after extubation (p<0.05). For apgar score, umbilical artery gas analysis and maternal awareness there were not significant differences between two groups. CONCLUSIONS: In comparison with thiopental-enflurane, propofol infusion (8 mg/kg/hr) coupled with N2O was proved to be clinically satisfactory anesthesia for cesarean section with no adverse effects on both mother and neonate.

The Evaluation of Intravenous Patient Controlled Analgesia and Continuous Epidural Analgesia for Pain Relief after Cesarean Delivery / 대한마취과학회지

BACKGROUND: Routine management of postoperative pain have been changed as a result of technological advances in drug delivery systems. The purpose of this study was to compare the effect of continuous epidural analgesia(CEA) system and intravenous patient controlled analgesia (IV-PCA) system for pain relief after cesarean delivery. METHODS: Sixty adult women were randomly assigned to receive analgesics either IV-PCA or CEA after cesarean delivery with general anesthesia for operation. IV-PCA group was received 30 mg intramuscular injection of ketorolac after awakening, followed by IV-PCA. PCA unit was filled with 60 ml; mixed with morphine 10 mg, fentanyl 1000 microgram, ketorolac 180 mg, and normal saline. It had a flow rate of 0.5 ml/hr and lockout interval was 15minutes. CEA group was received a bolus of epidural morphine 3mg and 8ml of 0.25% bupivacaine before the end of operation, followed by CEA. CEA unit was filled with 100 ml; mixed with morphine 4 mg, fentanyl 500 microgram, 0.5% bupivacaine 20 ml, and normal saline. It had a flow rate of 2ml/hr. The degree of analgesia was subjectively evaluated by a visual analogue scale(VAS). Patients were evaluated 0, 1, 2, 6, 12, 24, and 48hours after operation for pain relief, sedation, nausea, vomiting, pruritus, and respiratory rate. RESULTS: VAS pain score were significantly lower in CEA group than IV-PCA group at 0(8.0+/-1.4 vs 3.9+/-0.7), 1(4.4+/-1.3 vs 3.3+/-0.9) and 2hours(3.9+/-1.2 vs 3.3+/-0.8)(p<0.05). There were no apparent cases of respiratory depression and motor weakness of lower extrimity. Nausea or vomiting occurred in 7 patients(23%) of IV-PCA group, and occurred in 3 patients(10%) of CEA group. Pruritus occurred in 6 patients(20%) of IV-PCA group, and occurred in 11 patients (37%) of CEA group. Sedation occurred in 9 patients(30%) of IV-PCA group. Conculsions: We conclude that the CEA with small dose of morphine, fentanyl and bupivacaine is an easy and effective method for pain control after cesarean delivery.

Comparative Study of Spinal Anesthesia with 0.5% Hyperbaric Bupivacaine and 0.5% Hyperbaric Tetracaine in Cesarean Section / 대한마취과학회지

BACKGROUND: Marcaine is a recently introduced hyperbaric bupivacaine and may be suitable for spinal anesthetic solution in parturients undergoing cesarean section. Therefore, we have compared bupivacaine with tetracaine mostly used for spinal anesthesia in cesarean section, about maximum level of analgesia, the time taken to reach it, degree of motor block of lower extremities, degree of patient's satisfaction and cardiovascular variables. METHODS: Forty eight parturients were allocated to bupivacaine(n=26) or tetracaine(n=22) groups in random order. All patients received an infusion of lactated Ringer' solution(1,000 ml) and no premedication before spinal anesthesia. We used standardized techniques and injected the equal dose(10 mg) in equal volume(2 ml) intrathecally for spinal anesthesia. Maximum level of analgesia and time taken to reach it were checked by pinprick test, and degree of motor block was scored by Bromage scale. Blood pressure and heart rate were measured. RESULTS: There were no differences in maximum level of analgesia, motor block of low extremities, patient's satisfaction, blood pressure and heart rate between two groups. But the time taken to reach maximum level of analgesia was faster in the tetracaine group(8.3+/-2.3 min) than in the bupivacaine group(10.5+/-2.1 min)(p<0.05). The incidences of hypotension(systolic blood pressure<30% of preanesthesia value) were fewer in the bupivacaine(1 of 26) group than in the tetracaine group(6 of 22)(p<0.05). CONCLUSIONS: 0.5% hyperbaric bupivacaine reaches slower the maximum level of analgesia but induces fewer incidences of hypotension than 0.5% hyperbaric tetracaine. Therefore, hyperbaric bupivacaine is a safe and reliable anesthetic solution for spinal anesthesia in cesarean section.

Continuous Epidural Clonidine for Analgesia after Cesarean Section / 대한마취과학회지

BACKGROUND: Clonidine, an 2-adrenergic agonist, shows the analgesic effect and potentiates the analgesic effect of opioid. However, when it is injected with bolus technique, it reveals the short duration of inadequate analgesia and induces hypotension, bradycardia or sedation. We examined the analgesic and side effects of clonidine administered by continuous epidural infusion over 24 hrs, following epidural morphine injection. METHODS: Sixty parturients, scheduled for elective cesarean section under epidural anesthesia were randomly allocated into three groups. They received an infusion of saline alone (group 1, n= 20), clonidine 20 g/hr (group 2, n= 20), or 40 g/hr (group 3, n= 20) respectively, following epidural morphine 3 mg injection at the end of operation. The total doses and number of request for supplemental analgesic, blood pressure, heart rate, and degree of sedation were measured during 24 hrs. RESULTS: There were significant differences in pain relief between clonidine groups and group 1. The total doses and number of patient's request for supplemental analgesic in clonidine groups, compared to group 1 were significantly decreased (p<0.05), but no significant differences between the two clonidine groups. The diastolic pressure of group 3 was significantly lower than that of group 1 over 24 hrs, and that of group 2 at 18 hr, 24 hr (p<0.05). However, there was no severe hypotension, bradycardia or sedation in the three groups. CONCLUSION: Clonidine administered by continuous epidural infusion over 24 hrs enhances the analgesic effect of epidural morphine, and the infusion of clonidine with 20 g/hr rather than 40 g/hr shows minimal changes of blood pressure. Therefore, administration of epidural clonidine (20 g/hr) following epidural morphine may be considered as a regimen for pain management after cesarean section.

Effects of Intravenous Anesthetics on EEG Spectral Analysis during Cesarean Section / 대한마취과학회지

BACKGROUND: Anesthesia induces the spectral changes in EEG. Attempts to relate these spectral changes to adequacy of anesthesia have been hindered due to the complex waveforms of EEG. The objective of this investigation is to monitor the awareness of patients during cesarean section by means of EEG spectral analysis. METHODS: 20 patients for cesarean section aged from 24 to 39 and ASA class I or II, were maintained with O2(50%)-N2O(50%)-enflurane(0.8%). And they were administered with midazolam(0.07 mg/kg) in group I(n=6), fentanyl(1 microgram/kg) in group II(n=7), and fentanyl(2 microgram/kg) in group III(n=7) after birth. The density of each spectral band in EEG (delta 1-3.25 Hz, theta 3.5-7.75 Hz, alpha 8-12.15 Hz and beta 13-31.75Hz) was analyzed to derive total density, delta ratio and median power frequency. RESULTS: The spectral data demonstrated that the alpha rhythm was dominant in pre-induction period and beta rhythm was abundant both in the immediate post-induction period and after birth for all three groups. Delta ratio and median power frequency decreased after injection of midazolam and fentanyl in all three groups. None of patients could recall the memory about experience during cesarean section. CONCLUSIONS: These findings indicate that EEG spectral analysis is potentially useful to determine the changes of cerebroelectrical activity but difficult to monitor the awareness of patients during cesarean section.

Cardiovascular Blunting Effect of Magnesium Sulfate following Tracheal Intubation in Parturients undergoing Cesarean Section / 대한마취과학회지

Background; Tracheal intubation for cesarean section is usually performed with rapid sequence induction. Under this light stage of anesthesia, marked hypertensive changes of maternal hemodynamic responses following tracheal intubation may occur, which are the common cause of maternal and neonatal complications. We have studied the maternal cardiovascular blunting effect of magnesium sulfate following tracheal intubation in cesarean section. Methods; After obtaining the written informed consents, ninety ASA class I parturients scheduled for cesarean section were randomly allocated to one of three groups: group 1 received thiopental 4 mg/kg and succinylcholine 1.5 mg/kg, group 2 received fentanyl 1.5 microgramg/kg additionally, and group 3 received fentanyl 1.5 microgramg/kg and MgSO4 40 mg/kg additionally. Systolic, mean, diastolic blood pressure, and heart rate were measured before induction, immediately after intubation. Serum magnesium concentrations were measured before administering magnesium and near the end of surgery. Train of four ratio was monitored during whole period of anesthesia. Neonatal Apgar scores and neurologic and adaptive capacity scores (NACS) were checked. Results; Blood pressure changes were more stable in group 2 and group 3, especially group 3, than group 1 (p<0.05). No statistical differences were found in heart rate changes in all groups. No significant differences were noted in neuromuscular recoveries, neonatal Apgar scores and NACS. Conclusions; Magnesium sulfate may be successfully used for blunting the cardiovascular response to tracheal intubation in parturients undergoing general anesthesia for cesarean section.