Evidence That Intravenous Vasopressors Can Affect Rostral Spread of Spinal Anesthesia in Pregnancy

2004 ◽  
Vol 101 (1) ◽  
pp. 28-33 ◽  
Author(s):  
David W. Cooper ◽  
Leo Jeyaraj ◽  
Ryan Hynd ◽  
Rebekah Thompson ◽  
Tim Meek ◽  
...  
Keyword(s):  
Spinal Anesthesia ◽  
Cesarean Delivery ◽  
Epidural Space ◽  
Systolic Arterial Pressure ◽  
Light Touch ◽  
Double Blind ◽  
Touch Sensation ◽  
Upper Level ◽  
Combined Spinal Epidural Anesthesia ◽  
In Pregnancy

Background The authors have previously observed an apparent association between rostral spread of spinal anesthesia and choice of intravenous vasopressor given to maintain maternal systolic arterial pressure during cesarean delivery. This study tested the hypothesis that an intravenous infusion of phenylephrine can reduce rostral spread of spinal anesthesia in pregnancy, compared with ephedrine. Methods The study was randomized and double blind. It compared phenylephrine 100 microg/ml (phenylephrine group, n = 30), and ephedrine 3 mg/ml (ephedrine group, n = 30), given by infusion, to prevent maternal hypotension during combined spinal-epidural anesthesia for cesarean delivery. Two ml intrathecal plain levobupivacaine, 0.5%, combined with 0.4 ml intrathecal fentanyl, 50 microg/ml, and 10 ml epidural saline was given with the patient in the sitting position. The upper level of neural blockade to cold and light touch sensation was recorded at 10 and 20 min postspinal. Epidural space pressure was recorded at 5, 10, 15, and 20 min. Results At 20 min, the upper dermatome blocked to cold sensation was median T3 (interquartile range, T2-T4) for the phenylephrine group, compared with T1 (T1-T2) for the ephedrine group (P = 0.001). At 20 min, the upper dermatome blocked to light touch sensation was median T5 (T4-T8) for the phenylephrine group, compared with T3 (T2-T6) for the ephedrine group (P = 0.009). The mean epidural space pressure in the phenylephrine group was 16 (13-19) mmHg, compared with 16 (13-18) mmHg in the ephedrine group (P = 0.63). Conclusions This study provides evidence that intravenous phenylephrine can decrease rostral spread of spinal anesthesia in pregnancy, compared with intravenous ephedrine. Further work is required to investigate possible mechanisms and to assess its clinical significance.

Phenylephrine Added to Prophylactic Ephedrine Infusion during Spinal Anesthesia for Elective Cesarean Section

2001 ◽  
Vol 95 (3) ◽  
pp. 668-674 ◽  
Author(s):  
Frédéric J. Mercier ◽  
Edward T. Riley ◽  
Willard L. Frederickson ◽  
Sandrine Roger-Christoph ◽  
Dan Benhamou ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Spinal Anesthesia ◽  
Cesarean Delivery ◽  
Elective Cesarean Section ◽  
Hyperbaric Bupivacaine ◽  
Double Blind ◽  
Elective Cesarean ◽  
American Society ◽  
Spinal Hypotension

Background Because ephedrine infusion (2 mg/min) does not adequately prevent spinal hypotension during cesarean delivery, the authors investigated whether adding phenylephrine would improve its efficacy. Methods Thirty-nine parturients with American Society of Anesthesiologists physical status I-II who were scheduled for cesarean delivery received a crystalloid preload of 15 ml/kg. Spinal anesthesia was performed using 11 mg hyperbaric bupivacaine, 2.5 microg sufentanil, and 0.1 mg morphine. Maternal heart rate and systolic blood pressure were measured at frequent intervals. A vasopressor infusion was started immediately after spinal injection of either 2 mg/min ephedrine plus 10 microg/min phenylephrine or 2 mg/min ephedrine alone. Treatments were assigned randomly in a double-blind fashion. The infusion rate was adjusted according to systolic blood pressure using a predefined algorithm. Hypotension, defined as systolic blood pressure less than 100 mmHg and less than 80% of baseline, was treated with 6 mg ephedrine bolus doses. Results Hypotension occurred less frequently in the ephedrine-phenylephrine group than in the ephedrine-alone group: 37% versus 75% (P = 0.02). Ephedrine (36+/-16 mg, mean +/- SD) plus 178+/-81 microg phenylephrine was infused in former group, whereas 54+/-18 mg ephedrine was infused in the latter. Median supplemental ephedrine requirements and nausea scores (0-3) were less in the ephedrine-phenylephrine group (0 vs. 12 mg, P = 0.02; and 0 vs. 1.5, P = 0.01, respectively). Umbilical artery pH values were significantly higher in the ephedrine-phenylephrine group than in the group that received ephedrine alone (7.24 vs. 7.19). Apgar scores were similarly good in both groups. Conclusion Phenylephrine added to an infusion of ephedrine halved the incidence of hypotension and increased umbilical cord pH.

ED50and ED95of Intrathecal Hyperbaric Bupivacaine Coadministered with Opioids for Cesarean Delivery

2004 ◽  
Vol 100 (3) ◽  
pp. 676-682 ◽  
Author(s):  
Yehuda Ginosar ◽  
Edward Mirikatani ◽  
David R. Drover ◽  
Sheila E. Cohen ◽  
Edward T. Riley
Keyword(s):  
Cesarean Delivery ◽  
Intrathecal Morphine ◽  
Low Doses ◽  
Hyperbaric Bupivacaine ◽  
Double Blind ◽  
Elective Cesarean ◽  
Dose Ranging ◽  
Combined Spinal Epidural Anesthesia ◽  
Spinal Epidural ◽  
Speed Of Onset

Background Successful cesarean delivery anesthesia has been reported with use of small doses (5-9 mg) of intrathecal bupivacaine coadministered with opioids. This double-blind, randomized, dose-ranging study determined the ED50 and ED95 of intrathecal bupivacaine (with adjuvant opioids) for cesarean delivery anesthesia. Methods Forty-two parturients undergoing elective cesarean delivery with use of combined spinal-epidural anesthesia received intrathecal hyperbaric bupivacaine in doses of 6, 7, 8, 9, 10, 11, or 12 mg in equal volumes with an added 10 microg intrathecal fentanyl and 200 microg intrathecal morphine. Sensory levels (pinprick) were evaluated every 2 min until a T6 level was achieved. The dose was a success(induction) if a bilateral T6 block occurred in 10 min; otherwise, it was a failure(induction). In addition to being a success(induction), the dose was a success(operation) if no intraoperative epidural supplement was required; otherwise, it was a failure(operation). ED50 and ED95 for both success(induction) and success(operation) were determined with use of a logistic regression model. Results ED50 for success(induction) and success(operation) were 6.7 and 7.6 mg, respectively, whereas the ED95 for success(induction) and success(operation) were 11.0 and 11.2 mg. Speed of onset correlated inversely with dose. Although no clear advantage for low doses could be demonstrated (hypotension, nausea, vomiting, pruritus, or maternal satisfaction), this study was underpowered to detect significance in these variables. Conclusions The ED95 of intrathecal bupivacaine under the conditions of this study is considerably in excess of the low doses proposed for cesarean delivery in some recent publications. When doses of intrathecal bupivacaine less than the ED95, particularly near the ED50, are used, the doses should be administered as part of a catheter-based technique.

Fetal and Maternal Effects of Phenylephrine and Ephedrine during Spinal Anesthesia for Cesarean Delivery

2002 ◽  
Vol 97 (6) ◽  
pp. 1582-1590 ◽  
Author(s):  
David W. Cooper ◽  
Mark Carpenter ◽  
Paul Mowbray ◽  
William R. Desira ◽  
David M. Ryall ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Spinal Anesthesia ◽  
Cesarean Delivery ◽  
Systolic Arterial Pressure ◽  
Nausea And Vomiting ◽  
Combination Group ◽  
Routine Practice ◽  
The Mean ◽  
Fetal Acidosis ◽  
Group 1

Background In our routine practice, we observed a reduced incidence of fetal acidosis (umbilical artery pH < 7.20) at cesarean delivery during spinal anesthesia when a combination of phenylephrine and ephedrine was used as first line vasopressor therapy, compared with using ephedrine alone. Methods The study was randomized and double blind. It compared phenylephrine 100 microg/ml (phenylephrine group), ephedrine 3 mg/ml (ephedrine group), and phenylephrine 50 microg/ml combined with ephedrine 1.5 mg/ml (combination group), given by infusion, to maintain maternal systolic arterial pressure at baseline during spinal anesthesia for elective cesarean delivery. Results Fetal acidosis was less frequent in the phenylephrine group (1 of 48) (P = 0.004) and less frequent in the combination group (1 of 47) (P = 0.005) than in the ephedrine group (10 of 48). The mean systolic arterial pressure was similar for the three groups: Phenylephrine group median 98% (IQR 94-103) of baseline, ephedrine group 100% (96-106) and combination group 101% (97-108) (P = 0.11). The mean heart rate was higher in the ephedrine group (median 107% [IQR 99-118] of baseline) than in the phenylephrine group (88% [82-98]) (P < 0.0001), or the combination group (96% [86-102]) (P < 0.0001). Nausea and vomiting were less frequent in the phenylephrine group (nausea 17%, vomiting 0%) than in the ephedrine group (nausea 66%, vomiting 36%) (P < 0.0001), or the combination group (nausea 55%, vomiting 18%) (P < 0.0001). Conclusions Giving phenylephrine alone by infusion at cesarean delivery was associated with a lower incidence of fetal acidosis and maternal nausea and vomiting than giving ephedrine alone. There was no advantage to combining phenylephrine and ephedrine because it increased nausea and vomiting, and it did not further improve fetal blood gas values, compared with giving phenylephrine alone.

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