Hypertensive disorders of pregnancy among women with cardiovascular disease in Norway: A historical cohort study.

INTRODUCTION: Women with cardiovascular disease may be at increased risk of hypertensive disorders of pregnancy (HDP). We aimed to: (1) Investigate the occurrence of HDP in a cohort of pregnant women with cardiovascular disease and compare it with the occurrence in the general population. (2) Assess the association between maternal cardiovascular risk and risk of HDP. MATERIAL AND METHODS: We reviewed clinical data on a cohort of 901 pregnancies among 708 women with cardiovascular disease who were followed at the National Unit for Pregnancy and Heart Disease and gave birth at Oslo University Hospital between 2003 and 2018. The exposure under study was maternal cardiovascular risk, classified as low, moderate, or high based on a modified classification by the World Health Organization. The main outcome of interest was HDP, which included pre-eclampsia and gestational hypertension. The proportion of HDP cases in the general population in the same period was extracted from the Medical Birth Registry of Norway. We used logistic regression to estimate crude and adjusted odds ratios (OR) of HDP, with associated 95% confidence intervals (CIs), for women with moderate- and high cardiovascular risk compared to women with low risk. RESULTS: The occurrence of HDP in the study cohort was 12.1% (95% CI: 10.0%-14.4%) and varied between 8.7% (95% CI: 6.5%-11.3%) in the low-risk group, 15.7% (95% CI: 11.1%-21.4%) in the moderate-risk group, and 22.2% (95% CI: 15.1%-30.8%) in the high-risk group. By contrast, the nationwide occurrence of HDP was 5.1% (95% CI: 5.1%-5.2%). In the study cohort, the proportions of pregnancies with gestational hypertension and pre-eclampsia were similar (6.3% and 5.8%, respectively). Compared to pregnancies with low cardiovascular risk, the adjusted OR of HDP was 2.04 (95% CI: 1.21-3.44) in the moderate-risk group and 2.99 (95% CI: 1.73-5.18) in the high-risk group. CONCLUSIONS: The occurrence of hypertensive disease of pregnancy in the study cohort was more than doubled compared to the general population in Norway. The risk of HDP increased with maternal cardiovascular risk group. We recommend taking into account maternal cardiovascular risk group when assessing risk and prophylaxis of HDP.

Haemodynamic effects of remifentanil during induction of general anaesthesia with propofol. A randomised trial.

BACKGROUND: Remifentanil may have a dose-dependent haemodynamic effect during the induction of general anaesthesia combined with propofol. Our objective was to investigate whether systolic arterial blood pressure (SAP) was reduced to a greater extent when the remifentanil dose was increased. METHODS: This randomised, double-blind, dose-controlled study was conducted at the Day Surgery Unit of Haugesund Hospital, Norway. Ninety-nine healthy women scheduled for gynaecological surgery were randomly allocated in a 1:1:1 ratio to receive remifentanil induction with a low, medium or high dose corresponding to maximum effect-site concentrations (Ce) of 2, 4 and 8 ng/mL. The induction dose of propofol was 1.8 mg/kg, with a Ce of 2.9 µg/mL. Anaesthesia was induced using target-controlled infusion. After 150 s of sedation, a bolus of remifentanil and propofol was administered. Baseline was defined as 55-5 s before the bolus dose, and the total observation time was 450 s. We used beat-to-beat haemodynamic monitoring with LiDCOplus. The primary outcome variable was the maximum decrease in SAP within 5 min after bolus administration of remifentanil and propofol. Absolute and relative changes from baseline to minimal values and the area under the curve (AUC) were used as effect measures. Comparisons of groups were performed using analysis of variance (ANOVA). RESULTS: Median remifentanil doses were 0.75, 1.5 and 3.0 µg/kg in the low-, medium- and high-dose groups, respectively. The absolute changes (mean ± standard deviation) in SAP in the low-, medium- and high-dose groups of remifentanil were -39 ± 9.6 versus -43 ± 9.1, and -41 ± 10 mmHg, respectively. No difference (95% confidence interval) in the absolute change in SAP was observed between the groups (ANOVA, p = .29); medium versus low dose 3.7 (-2.0, 9.4) mmHg, and high versus medium dose -2.2 (-8.0; 3.5) mmHg. The relative changes from baseline to minimum SAP values were -30% versus -32% versus -32% (p = .52). The between-group differences in the AUC were not statistically significant. Relative changes in heart rate (-20% vs. -21% vs. -21%), stroke volume (-19% vs. -16% vs. -16%), cardiac output (-32% vs. -32% vs. -32%), systemic vascular resistance (-24% vs. -27% vs. -28%), and AUC were not statistically significant. CONCLUSION: This trial demonstrated major haemodynamic changes during the induction of anaesthesia with remifentanil and propofol. However, we did not observe any statistically significant differences between low, medium or high doses of remifentanil when using continuous invasive high-accuracy beat-to-beat monitoring.

Cardiorespiratory fitness in women after severe pre-eclampsia.

AIMS: To objectively study cardiorespiratory fitness (CRF) and physical activity (PA) and to evaluate limiting factors of exercise intolerance associated with poor CRF after severe pre-eclampsia. METHODS: In this single-centre, cross-sectional study, CRF was measured as peak oxygen uptake (VO2peak) during a cardiopulmonary exercise test (CPET) on a treadmill in women 7 years after severe pre-eclampsia. Ninety-six patients and 65 controls were eligible to participate. Cardiac output (CO) was measured by impedance cardiography. PA was measured using accelerometers. RESULTS: In 62 patients and 35 controls (mean age 40 ± 3 years), the VO2peak (in mL·kg-1·min-1) values were 31.4 ± 7.2 and 39.1 ± 5.4, respectively (p<0.01). In the patients, the COpeak was (9.6 L·min-1), 16% lower compared to controls (p<0.01). Twelve patients (19%) had a cardiac limitation to CPET. Twenty-three (37%) patients and one (3%) control were classed as unfit, with no cardiopulmonary limitations. The patients demonstrated 25% lower PA level (in counts per minute; p<0.01) and 14% more time being sedentary (p<0.01), compared with the controls. Twenty-one patients (34%) compared with four (17%) controls did not meet the World Health Organization's recommendations for PA (p=0.02). Body mass index and PA level accounted for 65% of the variability in VO2peak. CONCLUSION: Significantly lower CRF and PA levels were found in patients on long-term follow-up after severe pre-eclampsia. CPET identified cardiovascular limitations in one third of patients. One third appeared unfit, with adiposity and lower PA levels. These findings highlight the need for clinical follow-up and exercise interventions after severe pre-eclampsia.

High prevalence of pre-eclampsia in women with coarctation of the aorta.

Aims: The aim was to study pregnancy outcomes in women with coarctation of the aorta (CoA) and associations to hypertensive disorders of pregnancy. Maternal morbidity and mortality are higher in women with heart disease and pre-eclampsia. Chronic hypertension, frequently encountered in CoA, is a risk factor for pre-eclampsia. Methods and results: Clinical data from the National Unit for Pregnancy and Heart Disease database was reviewed for pregnant women with CoA from 2008 to 2021. The primary outcome was hypertensive pregnancy disorders. The secondary outcomes were other cardiovascular, obstetric, and foetal complications. Seventy-six patients were included, with a total of 87 pregnancies. Seventeen (20%) patients were treated for chronic hypertension before pregnancy. Fifteen (20%) patients developed pre-eclampsia, and 5 (7%) had pregnancy-induced hypertension. Major adverse cardiac events developed in four (5%) patients, with no maternal or foetal mortality. Maternal age at first pregnancy [odds ratio (OR) 1.37], body mass index before first pregnancy (OR 1.77), and using acetylsalicylic acid from the first trimester (OR 0.22) were statistically significantly associated with pre-eclampsia. At follow-up (median) 8 years after pregnancy, 29 (38%) patients had anti-hypertensive treatment, an increase of 16% compared to pre-pregnancy. Five (7%) patients had progression of aorta ascendens dilatation to >40 mm, seven (9%) had an upper to lower systolic blood pressure gradient >20 mmHg, and six (8%) had received CoA re-intervention. Conclusion: Pre-eclampsia occurred in 20% of women with CoA in their first pregnancy. All pre-eclamptic patients received adequate anti-hypertensive treatment. All CoA patients were provided multi-disciplinary management, including cardiologic follow-up, to optimize maternal-foetal outcomes.

Hemodynamic effects of a low versus a high dose of propofol during induction of anesthesia. A randomized trial.

BACKGROUND: Hypotension is common after anesthesia induction with propofol and is associated with increased morbidity. It is important to examine the effects of the proposed interventions to limit preventable hypotension, as suggested by the reduction in the dose of propofol. Our objective was to investigate whether a high dose of propofol is inferior to a low dose with respect to changes in systolic arterial blood pressure (SAP). METHODS: This randomized, double-blind, dose-controlled, non-inferiority study included 68 healthy women scheduled for gynecological surgery at the Day Surgery Unit, Haugesund Hospital, Norway. The patients were randomly allocated 1:1 to a low or high dose (1.4 mg/kg total body weight (TBW) versus 2.7 mg/kg TBW of propofol corresponding to maximal effect site concentrations (Ce) of 2.0 µg/mL versus 4.0 µg/mL. The dose of remifentanil was 1.9-2.0 µg/kg TBW, with maximal Ce of 5.0 ng/mL. The patients were observed for 450 s from the start of the infusions. The first 150 s was the sedation period, after which a bolus of propofol and remifentanil was administered. Baseline was defined as 55-5 s before the bolus doses. LiDCOplus was used for invasive beat-to-beat hemodynamic monitoring of changes in SAP, heart rate (HR), cardiac output (CO), stroke volume (SV), and systemic vascular resistance (SVR). A difference of 10 mmHg in the change in SAP was considered to be clinically important. RESULTS: The SAP change difference for low versus high dose was -2.9 mmHg (95% CI -9.0-3.1). The relative changes for low versus high dose were SAP -31% versus -36%, (p < .01); HR -24% versus -20%, (p = .09); SVR -20% versus -31%, (p < .001); SV -16% versus -20%, (p = .04); and CO -35% versus -32%, (p = .33). CONCLUSION: A high dose of propofol was not inferior to a low dose, and a reduction in the dose of propofol did not result in clinically important attenuation of major hemodynamic changes during induction in healthy women. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03861364, January 3, 2019.

Maternal beta-blocker dose and risk of small-for gestational-age in women with heart disease.

INTRODUCTION: Beta-blockers are prescribed for many pregnant women with heart disease, but whether there is a dose-dependent effect on fetal growth remains to be examined. We aimed to investigate if antenatal beta-blocker use and dose were associated with delivering a small-for-gestational-age infant among women with heart disease. MATERIAL AND METHODS: Our cohort included women with heart disease who delivered at Oslo University Hospital between 2006 and 2015. Maternal heart disease was classified into modified WHO risk scores. Women with beta-blocker treatment were dichotomized into whether they had been treated with a low or high dose based on clinical factors. We compared the risk of delivering a small-for-gestational-age infant in women exposed to high doses, low doses, or with no exposure to antenatal beta-blockers while adjusting for severity of maternal heart disease in logistic regression models. RESULTS: Of a total of 540 pregnancies among women with heart disease, 163 (30.2%) were exposed to beta-blocker treatment. The majority were treated with metoprolol (86.5%). Almost twice as many babies in the beta-blocker group were small-for-gestational-age, compared with the non-exposed group (19.8 vs 9.5%, P < 0.001). Women using a high-dose beta-blocker had a five-fold increased risk of delivering a small-for-gestational-age infant compared with non-exposure (adjusted odds ratio [aOR] 4.89, 95% confidence interval [CI] 2.22-10.78, P < 0.001). Women using a low dose of beta-blocker had a two-fold increased risk of delivering a small-for-gestational-age infant; however, the confidence interval included the null (aOR 1.75, 95% CI 0.83-3.72, P = 0.143). Results when restricting the analyses to metoprolol showed the same pattern, but with attenuation of risks. CONCLUSIONS: We found a five-fold increased risk of delivering a small-for-gestational-age infant in women with heart disease treated with a high dose of beta-blocker, and a two-fold increased risk among those treated with a low dose, showing an apparent dose-response relation. Close monitoring of fetal growth is warranted among women with heart disease treated with beta-blockers. As drug therapy in pregnancy concerns both mother and fetus, an optimum balance for both should be the goal.

Haemodynamic stability after paracervical block: A randomized, controlled, double-blind study comparing bupivacaine-adrenaline with bupivacaine.

BACKGROUND: Paracervical block is widely used in gynaecological interventions on cervix and uterus. Many surgeons add adrenaline 100 µg or pitressin 3-5 IU in a total volume of 10-20 mL to reduce total blood loss. We wanted to examine haemodynamic stability in healthy patients given bupivacaine with and without adrenaline. METHODS: In this randomised, double-blinded, controlled study, 30 healthy women scheduled for cervical conisation got a paracervical block using bupivacaine 50 mg with adrenaline 100 µg (BA-group, n = 14) or without adrenaline (B-group, n = 16) after induction of general anaesthesia. LiDCOplus was used for minimally invasive haemodynamic monitoring. Changes in cardiac output (CO) and systolic blood pressure (SBP) were the primary outcome. Changes in heart rate (HR), stroke volume (SV), and systemic vascular resistance (SVR) were secondary outcome variables. Area under the curve (AUC) ratios and change from baseline to maximal values were used as effect measures comparing the two groups. RESULTS: The AUC-ratio for CO and SBP was 2.50 (P < 0.001) and 1.70 (P = 0.03), respectively. For HR, SV, and SVR the AUC-ratio was 1.59 (P < 0.01), 1.52 (P < 0.001), and 0.90 (P = 0.14), respectively. CO increased 68% (standard deviation (SD) 42%, P < 0.001), HR increased 41% (SD 26%, P < 0.001), and SV increased 26% (SD 17%, P < 0.001) from baseline to maximal values after 70-90 seconds in the BA-group. CONCLUSION: Paracervical block with bupivacaine 50 mg and adrenaline 100 µg may give haemodynamic instability in healthy females and is not recommended if haemodynamic side effects are to be avoided.

The Analgesic Effect of Ultrasound-Guided Quadratus Lumborum Block After Cesarean Delivery: A Randomized Clinical Trial.

BACKGROUND: Landmark and ultrasound-guided transversus abdominis plane blocks have demonstrated an opioid-sparing effect postoperatively after cesarean delivery. The more posterior quadratus lumborum (QL) might provide superior local anesthetic spread to the thoracolumbar fascia and paravertebral space. The aim of our study was to evaluate the efficacy of the QL block after cesarean delivery. METHODS: A randomized, double-blind, controlled trial was performed. Forty parturients undergoing cesarean delivery received bilateral ultrasound-guided QL blocks with either 2 mg/mL ropivacaine or saline postoperatively. All patients received spinal anesthesia with bupivacaine and sufentanil and a postoperative analgesic regimen of paracetamol, ibuprofen, and ketobemidone administered by a patient-controlled analgesic pump. The ketobemidone consumption and time of each dose administered were recorded. The primary outcome was ketobemidone consumption during the first 24 hours postoperatively. Secondary and exploratory analyses compared repeated measures of pain scores, nausea, and fatigue, and total differences in time until patients were able to stand and able to walk 5 m, and the interaction between the effective analgesic score and time. RESULTS: All 40 patients completed the trial, 20 in each group. The cumulative ketobemidone consumption in 24 hours was reduced in the active group compared with the control group (P = .04; ratio of means = 0.60; 95% confidence interval, 0.37-0.97). The effective analgesic scores were significantly better in the treatment group compared with the placebo group both at rest (P < .01) and during coughing (P < .01). CONCLUSIONS: QL block with ropivacaine reduces the postoperative ketobemidone consumption and pain intensity as a part of a multimodal analgesic regimen that excludes neuraxial morphine.

Hemodynamics of Phenylephrine Infusion Versus Lower Extremity Compression During Spinal Anesthesia for Cesarean Delivery: A Randomized, Double-Blind, Placebo-Controlled Study.

BACKGROUND: Phenylephrine infusion is the current first-line choice for prevention of spinal hypotension during cesarean delivery. The optimal dosage regimen is still undetermined. A mechanical alternative, lower limb wrapping, has been examined in a few small studies showing moderate success. In this trial, we compared the effect of leg wrapping with low-dose phenylephrine infusion and with placebo treatment on systolic arterial blood pressure during spinal anesthesia for cesarean delivery. METHODS: In this randomized, double-blinded, placebo-controlled study, healthy women received either phenylephrine (n = 38; initial bolus of 0.25 µg kg and infusion of 0.25 µg kg min), leg wrapping (n = 38), or no treatment (control; n = 36) during spinal anesthesia for elective cesarean delivery. LiDCOplus was used for continuous minimally invasive hemodynamic monitoring. The extent of decrease in systolic arterial blood pressure (for 13 minutes after spinal induction) was the primary outcome. Cardiac output, systemic vascular resistance, stroke volume, heart rate, neonatal acid-base status, and Apgar score were secondary outcome variables. Mixed model analysis of continuous hemodynamic trends during the first 13 minutes after induction of spinal anesthesia was performed. RESULTS: In the phenylephrine group, the decrease in systolic arterial blood pressure was significantly less (difference in rate of change, 0.09 mm Hg 5 s; 95% confidence interval, 0.02-0.16; P = 0.013); systemic vascular resistance (P < 0.001) was significantly higher; stroke volume (P = 0.41) was similar; and heart rate (P = 0.002) and cardiac output (P < 0.001) were significantly lower compared with the leg wrapping group. Compared with control, the leg wrapping group had a significantly smaller decrease in systolic arterial blood pressure (0.39 mm Hg 5 s; 95% confidence interval, 0.32-0.46; P < 0.001), higher stroke volume (P < 0.001), and higher cardiac output (P = 0.001). CONCLUSIONS: An initial bolus of phenylephrine followed by a low-dose phenylephrine infusion was superior to leg wrapping and no intervention for the prevention of hypotension during spinal anesthesia for cesarean delivery. Phenylephrine prevented hypotension primarily by restoring systemic vascular resistance and did not cause hypertension or a clinically relevant reduction in cardiac output. Leg wrapping prevented hypotension compared with no intervention by limiting modest early spinal anesthesia-mediated venodilation.

The role of cardiac output monitoring in obstetric anesthesia.

PURPOSE OF REVIEW: Haemodynamic monitoring in obstetric patients has evolved during the last decade, with the development of minimally invasive and noninvasive continuous cardiac output (CO) monitors. This review focuses on recent articles that improve our understanding of physiology and haemodynamic changes during spinal anaesthesia in healthy pregnant women, and pathophysiology in women with preeclampsia and other cardiovascular disease. RECENT FINDINGS: Recent research findings in healthy women focus on the haemodynamic changes due to aortocaval compression, fluid administration, vasopressor therapy, and oxytocin during spinal anaesthesia for caesarean delivery. In preeclampsia, the haemodynamics of early versus late-onset disease and fluid management have been the subject of considerable investigation. Case reports suggest that invasive monitoring in combination with echocardiography is preferable for clinical management of high-risk obstetrics cases with unstable haemodynamics. SUMMARY: In healthy women, left lateral tilt remains an important clinical intervention during caesarean delivery, and phenylephrine is an essential early adjunct to fluid therapy. Noradrenaline may have a clinical benefit in selected patients. Carbetocin has similar haemodynamic effects to oxytocin. Haemodynamic changes associated with delivery per se may be minor compared with those due to oxytocin. Uncomplicated severe preeclampsia is usually associated with a normal to raised CO. Early-onset preeclampsia may be associated with more vasoconstriction and lower CO than late-onset disease. Passive leg raising may be useful to judge fluid responsiveness, and lung ultrasound may predict pulmonary oedema in preeclampsia. Further research is warranted to study the area of circulatory changes during delivery and the postpartum period, in healthy and preeclamptic women.

Changes in blood pressure and cardiac output during cesarean delivery: the effects of oxytocin and carbetocin compared with placebo.

BACKGROUND: Little is known about maternal hemodynamics after Cesarean delivery. Uterine contractions may increase cardiac output. Oxytocin is the first-line treatment for uterine atony, although the effects of the long-acting oxytocin analogue carbetocin are comparable with that of oxytocin. The authors analyzed the effects of i.v. oxytocin 5 U, carbetocin 100 µg, and placebo on hemodynamics, uterine tone, adverse events, and blood loss after Cesarean delivery. METHODS: This was a randomized, double-blinded, placebo-controlled, parallel-group comparison of carbetocin and oxytocin after elective Cesarean delivery of singletons under spinal anesthesia (n = 76). Continuously measured invasive systolic arterial pressure was the primary outcome measure. RESULTS: The mean systolic arterial pressure decrease was 28 mmHg (95% CI, 22-34) after oxytocin and 26 mmHg (95% CI, 20-31) after carbetocin. The decrease was greatest after 80 (95% CI, 71-89) and 63 s (95% CI, 55-72), respectively (P = 0.006). The differences were nearly undetectable after 2.5 min, although the effect of carbetocin was slightly greater than placebo (P < 0.001). The group differences in systolic arterial pressure decreased over 5 min and were gone at 1 h. Heart rate and cardiac output increased in all three groups. Stroke volume increased after oxytocin and carbetocin but was unchanged after placebo. CONCLUSIONS: The hemodynamic side effects of oxytocin 5 U and carbetocin 100 µg were comparable. The lack of an increase in stroke volume in the placebo group challenges the theory that uterine contraction causes autotransfusion of uterine blood, leading to an increase in preload.

Changes in blood pressure during healthy pregnancy: a longitudinal cohort study.

OBJECTIVE: To study longitudinally changes in blood pressure (BP) and heart rate (HR) during healthy pregnancies and to evaluate the influence of parity, pregestational overweight, and excessive weight gain. METHODS: A prospective longitudinal cohort study of 57 healthy white women with singleton pregnancies. BP and HR were measured repeatedly at gestational age 14-16 weeks, 22-24 weeks, 30-32 weeks, 36 weeks, and 6 months postpartum using both an oscillometric measurement device (Dinamap) and finger arterial pressure (Finometer PRO). RESULTS: SBP, DBP, and mean arterial pressure (MAP) reached a statistically significant trough at gestational age 22-24 weeks using both measurement devices. When compared with the nonpregnant measurement, SBP at gestational age 22-24 weeks was 6.2 mmHg [95% confidence interval (95% CI) 1.3-11.2] lower measured by Finometer and 7.2 mmHg (95% CI 4.2-10.1) lower measured by Dinamap. DBP and MAP were 8.9 mmHg (95% CI 4.6-13.2) and 9.8 mmHg (95% CI 5.3-14.2) lower measured by Finometer. Measured by Dinamap, DBP and MAP were 4.5 mmHg (95% CI 1.7-7.3) and 5.4 mmHg (95% CI 2.8-7.9) lower at gestational age 22-24 weeks when compared with the nonpregnant state. SBP was significantly higher in women with pregestational BMI at least 25 kg/m with both measurement devices (both P < 0.05). There were no differences in SBP, DBP, or MAP depending on parity or excessive weight gain. CONCLUSION: BP measured repeatedly by two different noninvasive devices during pregnancy and postpartum showed a statistically significant drop in mid-pregnancy, followed by a progressive increase until term.

Maternal haemodynamic changes during spinal anaesthesia for caesarean section.

PURPOSE OF REVIEW: Maternal haemodynamic changes during spinal anaesthesia for caesarean section have traditionally been evaluated by noninvasive blood pressure and heart rate. Recent publications have addressed the importance of cardiac output measurement in the assessment of the maternal circulation. In this review, a physiological approach is suggested for the prevention and treatment of haemodynamic instability during caesarean section in healthy women and in those with preeclampsia or cardiac disease. RECENT FINDINGS: A better understanding of the maternal haemodynamic effects of spinal anaesthesia and the effects of vasopressors has emerged from the monitoring of cardiac output during caesarean section in healthy women and in those with severe preeclampsia or cardiac disease. Based on maternal physiological arguments, phenylephrine is the vasopressor of choice in healthy pregnant women. New work demonstrating cardiac dysfunction in some women with severe preeclampsia has implications for risk assessment and anaesthesia. Recent publications suggest that combined spinal-epidural and continuous spinal anaesthesia is well tolerated in pregnant women with cardiac disease. SUMMARY: The most frequent response to spinal anaesthesia for elective caesarean section is a marked decrease in systemic vascular resistance and partial compensation from increased stroke volume and heart rate. Early administration of phenylephrine by bolus or continuous infusion is indicated in most cases. Recent work has expanded our knowledge of the therapeutic range of phenylephrine and indicates that the heart rate response to vasopressors is a good surrogate marker for cardiac output. Further research should examine haemodynamic changes during spinal anaesthesia in high-risk pregnant women with early onset preeclampsia or cardiac disease.

Continuous invasive blood pressure and cardiac output monitoring during cesarean delivery: a randomized, double-blind comparison of low-dose versus high-dose spinal anesthesia with intravenous phenylephrine or placebo infusion.

BACKGROUND: Prevention of hemodynamic instability during cesarean delivery during spinal anesthesia has been the aim of several studies. Noninvasive monitoring has been used in all previous studies. This is the first study in healthy pregnant women with continuous invasive recording of arterial blood pressure, cardiac output, and systemic vascular resistance. The aim of this randomized trial was to compare the effects of two different intrathecal doses of bupivacaine, with or without intravenous phenylephrine infusion, on cardiac output and systolic blood pressure. METHODS: In this double-blinded study, 80 healthy women scheduled to undergo elective cesarean delivery were randomly assigned to one of four different groups receiving 7 mg spinal bupivacaine with or without a concomitant low-dose infusion of phenylephrine (0.25 microg . kg(-1) . min(-1)) or 10 mg spinal bupivacaine with or without phenylephrine infusion. All patients had 4 microg sufentanil added to the spinal solution and had cohydration with 750 ml saline, 0.9%. RESULTS: The low-dose spinal bupivacaine group with intravenous phenylephrine infusion was the most stable group regarding all hemodynamic variables. The authors found significant differences between this group and the group that was given the high dose of bupivacaine with intravenous placebo infusion regarding cardiac output (P = 0.005), systemic vascular resistance (P < 0.0001), and systolic blood pressure (P = 0.012). CONCLUSIONS: This study shows that low-dose bupivacaine (with sufentanil), combined with a low-dose infusion of phenylephrine and moderate cohydration, gives the best hemodynamic stability during spinal anesthesia for cesarean delivery.