Cosmas van de Ven

Relative Analgesic Potencies of Ropivacaine and Bupivacaine for Epidural Analgesia in Labor Implications for Therapeutic Indexes

Background The minimum local analgesic concentration (MLAC) has been defined as the median effective local analgesic concentration in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to assess the relative analgesic potencies of epidural bupivacaine and ropivacaine by determining their respective minimum local analgesic concentrations. Methods Seventy-three parturients at Results The minimum local analgesic concentration of ropivacaine was 0.111% wt/vol (95% confidence interval, 0.100-0.122), and the minimum local analgesic concentration of bupivacaine was 0.067% wt/vol (95% confidence interval, 0.052-0.082). Ropivacaine was significantly less potent than bupivacaine, with a potency ratio of 0.6 (95% confidence interval, 0.49-0.74). No difference in motor effects was observed. Conclusion Ropivacaine was significantly less potent than bupivacaine for epidural analgesia in the first stage of labor.

Hyperkinetic borderline hypertension in Tecumseh, Michigan

Of 691 healthy (untreated) villagers of Tecumseh, Michigan (average age 32.6 years), 99 had a clinical blood pressure exceeding 140/90 mmHg. Thirty-seven per cent of these borderline hypertensives had increased heart rate, cardiac index, forearm blood flow and plasma norepinephrine. These subjects had elevated self-determined home blood pressure (average of 14 measurements). The present hyperkinetic borderlines had elevated blood pressure at 5, 8, 21 and 23 years of age and their parents also had higher blood pressure. The prevalence of high blood pressure in Tecumseh, its long history, elevated blood pressure readings outside the physicians office and family background of hypertension, suggests that the hyperkinetic state is a significant clinical condition. Previous studies on hospital-based populations proved that the hyperkinetic state is caused by an excessive autonomic drive. The association of the hyperkinetic state with elevated norepinephrine in this study suggests that a sympathetic hyperactivity is present in a large proportion of unselected subjects with mild blood pressure elevation.

Relative Analgesic Potencies of Levobupivacaine and Ropivacaine for Epidural Analgesia in Labor

Background The minimum local analgesic concentration has been defined as the median effective local analgesic concentration (EC50) in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to assess the relative analgesic potencies of epidural levobupivacaine and ropivacaine by determination of their respective minimum local analgesic concentrations. Methods Parturients at 7 cm of cervical dilation or less who requested epidural analgesia were allocated to one of two groups in this double-blind, randomized, prospective study. After lumbar epidural catheter placement, 20 ml of the test solution was given: levobupivacaine (n = 35) or ropivacaine (n = 35). The concentration of local anesthetic was determined by the response of the previous patient in that group to a higher or lower concentration using up–down sequential allocation. Analgesic efficacy was assessed using 100-mm visual analog pain scale scores, with 10 mm or less within 30 min defined as effective. An effective result directed a 0.01% wt/vol decrement for the next patient. An ineffective result directed a 0.01% wt/vol increment. Results Of 105 women enrolled, 35 were excluded, leaving 70 for analysis. The minimum local analgesic concentration of levobupivacaine was 0.087% wt/vol (95% CI, 0.081–0.094%), and the minimum local analgesic concentration of ropivacaine was 0.089% wt/vol (95% CI, 0.075–0.103%). Levobupivacaine and ropivacaine were of similar potency with a ropivacaine:levobupivacaine potency ratio of 0.98 (95% CI, 0.80–1.20). No difference in motor effects was observed. Conclusions This study demonstrated that levobupivacaine and ropivacaine are of similar potency for epidural analgesia in the first stage of labor.

Effect of Intravenous versus Epidural Fentanyl on the Minimum Local Analgesic Concentration of Epidural Bupivacaine in Labor

Background The minimum local analgesic concentration (MLAC) has been defined as the median effective local analgesic concentration (EC50) in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to determine the relative local anesthetic sparing efficacies of intravenous and epidural fentanyl by comparison of their effects on the MLAC of bupivacaine. Methods In this double-blind, randomized, prospective study, 84 parturients at ≤ 7-cm cervical dilation who requested epidural analgesia were allocated to one of two groups. After lumbar epidural catheter placement, 20 ml bupivacaine (n = 44) or bupivacaine with 3 &mgr;g/ml (60 &mgr;g) fentanyl (n = 40) was administered. The plain bupivacaine group then received 60 &mgr;g intravenous fentanyl. The bupivacaine–fentanyl group received intravenous saline. The concentration of bupivacaine was determined by the response of the previous patient in that group to a higher or lower concentration using up–down sequential allocation. Analgesic efficacy was assessed using 100-mm visual analog pain scores, with ≤ 10 mm within 30 min defined as effective. Results The MLAC of bupivacaine–intravenous fentanyl was 0.064% wt/vol (95% confidence interval, 0.049–0.080), and the MLAC of bupivacaine–epidural fentanyl was 0.034% wt/vol (95% confidence interval, 0.017–0.050). Epidural fentanyl significantly increased the analgesic potency of bupivacaine by a factor of 1.88 (95% confidence interval, 1.09–3.67) compared with intravenous fentanyl. The epidural fentanyl group demonstrated significantly higher dermatomal spread (P = 0.0064) and increased pruritus (P = 0.01). Conclusions Epidural fentanyl significantly reduced the MLAC of bupivacaine when compared with intravenous fentanyl for the parturients in this study. The significantly enhanced local anesthetic sparing, dermatomal level, and pruritus with epidural fentanyl suggest a primarily spinal site of action.

Seasonal influenza A (H1N1) infection in early pregnancy and second trimester fetal demise

A second trimester fetal demise followed influenza-like illness in early pregnancy. Influenza A virus (H1N1) was identified in maternal and fetal tissue, confirming transplacental passage. These findings suggested a causal relationship between early exposure and fetal demise. Management of future influenza outbreaks should include evaluation of products of conception associated with fetal loss.

Effect of epidural epinephrine on the minimum local analgesic concentration of epidural bupivacaine in labor

Background The minimum local analgesic concentration (MLAC) has been defined as the median effective local analgesic concentration in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to determine the local anesthetic–sparing efficacy of epidural epinephrine by its effect on the MLAC of bupivacaine. Methods In this double-blind, randomized, prospective study, 70 parturients who were at 7 cm or less cervical dilation and who requested epidural analgesia were allocated to one of two groups. After lumbar epidural catheter placement, 20 ml bupivacaine (n = 35) or bupivacaine with epinephrine 1:300,000 (n = 35) was administered. The concentration of bupivacaine was determined by the response of the previous patient in that group to a higher or lower concentration using up–down sequential allocation. Analgesic efficacy was assessed using 100-mm visual analog pain scores, with 10 mm or less within 30 min defined as effective. Results The MLAC of bupivacaine alone was 0.091% wt/vol (95% confidence interval, 0.081–0.102). The addition of epinephrine 1:300,000 (66.7 &mgr;g) resulted in a significant reduction (P < 0.01) in the MLAC of bupivacaine to 0.065% wt/vol (95% confidence interval, 0.047–0.083). The lowest maternal blood pressure was significantly lower in the bupivacaine–epinephrine group (P = 0.03). There were statistically significant reductions in fetal heart rate (P = 0.011) in the bupivacaine–epinephrine group that were not clinically significant. Conclusions The addition of epidural epinephrine 1:300,000 (66 &mgr;g) resulted in a significant 29% reduction in the MLAC of bupivacaine. Coincident reductions in fetal heart rate and maternal blood pressure were also observed that were not clinically significant.

Service use data analysis of pre-pregnancy psychiatric and somatic diagnoses in women with hyperemesis gravidarum

Introduction. The purpose of this study was to redress weaknesses in past studies of a psychogenic etiology for hyperemesis gravidarum (HG) by (1) estimating from a known population what proportion of HG cases also have psychiatric diagnoses, (2) determining if psychiatric disorder preceded HG, and (3) re-considering whether non-pregnancy somatic conditions also precede HG. Methods. We analyzed insurance data for all 11,016 members who gave birth to singletons in 2000–2004, 208 of whom had HG. Results. Prevalence of HG was 1.8% overall, 3.8% with one psychiatric diagnosis, 5.8% with >1 psychiatric diagnosis. One in 10 HG cases had pre-pregnancy depression, anxiety, or substance abuse diagnoses. One in five HG cases had either a psychiatric or a somatic condition (e.g., chronic pelvic pain, dysmenorrhea) diagnosis prior to pregnancy. Pre-pregnancy psychiatric diagnosis doubled the adjusted odds of HG. Combined psychiatric and somatic diagnoses quadrupled the adjusted odds of HG. Discussion. Vomiting is a non-specific sign that may have multiple etiologies. For 10–20% of HG sufferers, vomiting may be a physical comorbidity of a psychiatric condition occurring in the context of pregnancy. Psychobiological research with HG cases with past or current psychiatric diagnoses is needed to consider plausible mechanisms.

Obstetric management of 219 infants with hypoplastic left heart syndrome

OBJECTIVE The objective of this study was to describe the obstetric parameters from 219 deliveries of infants with hypoplastic left heart syndrome. STUDY DESIGN The Pediatric Cardiovascular Surgery Database at the University of Michigan was searched, and cases of neonates with the diagnosis of hypoplastic left heart syndrome were found. Obstetric records were then reviewed. RESULTS One hundred sixty-one infants (74%) were delivered vaginally and 58 (26%) were delivered by the cesarean route. The mean gestational age at delivery was 38.9 weeks. Mean Apgar scores at 1 and 5 minutes were 7 and 8, respectively. Ninety percent were delivered at term and 10% were delivered before 37 weeks. The diagnosis of hypoplastic left heart syndrome was made antenatally in 82 cases (37%) and neonatally in 137 cases (63%). In the antenatal group the mean gestational age at diagnosis was 27 weeks. Karyotype analysis was performed in 32 of all cases (15%), with 8 fetuses revealing an abnormal karyotype. Seven cases were 45,X and 1 was trisomy 21. CONCLUSION Staged reconstruction surgery has markedly improved survival for neonates born with isolated hypoplastic left heart syndrome. Our review suggests that, aside from determining the karyotype, no further obstetric interventions seem warranted. While awaiting spontaneous labor at term, the planned mode of delivery should be vaginal, with cesarean delivery performed for routine obstetric indications only.

Critical care in obstetrics: pregnancy-specific conditions

This chapter summarizes the clinical presentation, pathophysiology, evaluation and management of six commonly encountered complications unique to pregnancy that require critical care management: obstetric haemorrhage; pre-eclampsia/HELLP (haemolysis-elevated liver enzymes-low platelets) syndrome; acute fatty liver of pregnancy; peripartum cardiomyopathy; amniotic fluid embolism; and trauma.

Outcome of infants with hypoplastic left heart and Turner syndromes.

OBJECTIVE To report the obstetric and neonatal outcomes of ten infants with hypoplastic left heart syndrome in association with Turner syndrome. METHODS The Pediatric Cardiovascular Surgery database at the University of Michigan was searched from 1990 to 1997, and obstetric and neonatal records of neonates with hypoplastic left heart syndrome and Turner syndrome were reviewed. RESULTS There were 406 cases of hypoplastic left heart syndrome admitted during 8 years, of which ten (2.5%) also had Turner syndrome. Nine infants were delivered at term and one at 36 weeks. The mean (+/- standard deviation [SD]) gestational age at delivery was 38 +/- 1.2 weeks, and mean (+/-SD) birth weight was 2991 +/- 438 g. Delivery was vaginal in all cases, and no infant had an Apgar score at 5 minutes less than 7. Karyotype was 45, X in seven cases, and 45, X mosaic in three. Most infants had dysmorphic features at birth. All ten infants had first-stage reconstruction surgery for hypoplastic left heart syndrome. Only two survived and underwent second-stage palliation; both are alive currently, although with significant medical problems. CONCLUSION For infants with hypoplastic left heart and Turner syndromes, regular obstetric management appears appropriate. Although staged reconstruction surgery has improved survival for neonates with isolated hypoplastic left heart syndrome, for those with Turner syndrome, survival appears markedly reduced.