Branko M. Weiss

Outcome of pulmonary vascular disease in pregnancy: a systematic overview from 1978 through 1996

OBJECTIVES Published reports were reviewed to evaluate the characteristics of peripartal management and the late pregnancy outcome in women with pulmonary vascular disease (PVD). BACKGROUND Pulmonary hypertension poses one of the highest risks for maternal mortality, but actual data on the maternal and neonatal prognosis in this group are lacking. METHODS Reports published from 1978 through 1996 of Eisenmengers syndrome (n = 73), primary pulmonary hypertension (PPH) (n = 27) and secondary vascular pulmonary hypertension (SVPH) (n = 25) complicating late pregnancy were included and analyzed using logistic regression analysis. RESULTS Maternal mortality was 36% in Eisenmengers syndrome, 30% in PPH and 56% (p < 0.08 vs. other two groups) in SVPH. Except for three prepartal deaths due to Eisenmengers syndrome, all fatalities occurred within 35 days after delivery. Neonatal survival ranging from 87% to 89% was similar in the three groups. Previous pregnancies, timing of the diagnosis and hospital admission, operative delivery and diastolic pulmonary artery pressure were significant univariate (p < 0.05) maternal risk factors. Late diagnosis (p = 0.002, odds ratio 5.4) and late hospital admission (p = 0.01, odds ratio 1.1 per week of pregnancy) were independent predictive risk factors of maternal mortality. CONCLUSIONS In the last two decades maternal mortality was comparable in patients with Eisenmengers syndrome and PPH; however, it was relevantly higher in SVPH. Maternal prognosis depends on the early diagnosis of PVD, early hospital admission, individually tailored treatment during pregnancy and medical therapy and care focused on the postpartal period.

Outcome of cardiovascular surgery and pregnancy: A systematic review of the period 1984-1996 ☆ ☆☆

The outcomes of cardiovascular operations during pregnancy, at delivery, and post partum were reviewed from published material in the period 1984-1996. Surgery during pregnancy resulted in fetal-neonatal morbidity and mortality of 9% and 30%, respectively, and in maternal morbidity and mortality of 24% and 6%, respectively. Duration of pregnancy at surgery and duration and temperature of cardiopulmonary bypass did not influence fetal-neonatal outcome. Maternal complications and mortality of surgery immediately after delivery were 29% and 12%, respectively, and for surgery performed with a postpartum interval the respective rates were 38% and 14%. Hospitalization after week 27 of gestation and extreme emergency contributed significantly to poor maternal outcome. Maternal deaths were reported in 9% of valvular procedures and in 22% of aortic or arterial dissection repairs and pulmonary embolectomies. Fetal-neonatal risks of maternal surgery during pregnancy are high and unpredictable. Maternal risks of cardiovascular procedures during pregnancy are moderate, significantly increase if an operation is performed at or after delivery, and, overall, should be considered as higher than those in nonpregnant cardiovascular surgical patients.

Risk and benefit of low systemic heparinization during open heart operations

Heparin surface-coated perfusion equipment with improved thromboresistance was evaluated in 104 consecutive patients undergoing open heart operation in a prospective, randomized trial with low versus full systemic heparinization. Surgical procedures included coronary artery revascularization in 47 of 54 (87%) for low versus 44 of 50 patients (88%; not significant [NS]) for full, valve repair/replacement in 8 of 54 (15%) for low versus 5 of 50 patients (10%; NS) for full, left ventricular aneurysm repair in 1 of 54 (2%) for low versus 2 of 50 patients (4%; NS) for full, and other in 3 of 54 (6%) for low versus 3 of 50 patients (6%; NS) for full. Cross-clamp time was 39.2 +/- 10.7 minutes for low versus 39.5 +/- 10.5 minutes for full (NS). Cardiopulmonary bypass time was 68.6 +/- 20.1 minutes for low versus 69.3 +/- 16.6 minutes for full (NS). Lowest activated coagulation time during perfusion was 255 +/- 75 seconds for low versus 537 +/- 205 seconds for full (p < 0.0005). In the low group, the target activated coagulation time of more than 180 seconds was not reached during perfusion in 4 of 54 patients (7%), the lowest value being 164 seconds. No oxygenator failure occurred. Hospital mortality was 0 of 54 (0%) for low versus 1 of 50 patients (2%) for full (NS). Bleeding required surgical revision in 0 of 54 (0%) for low versus 4 of 50 patients (8%) for full (p = 0.05). Drainage (24 hours) was 790 +/- 393 mL for low versus 1,039 +/- 732 mL for full (p < 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Electromyographic Comparison of Obturator Nerve Block to Three-in-one Block

Obturator nerve block during spinal, epidural, or general anesthesia without muscle relaxants has been recommended for transurethral surgery to prevent thigh adductor muscle contractions during operative electrocautery.We investigated the effectiveness of direct obturator and 3-in-1 nerve motor blocks in 44 patients undergoing transurethral surgery during spinal anesthesia with isobaric bupivacaine. Patients were randomly assigned to receive 3-in-1 block with 40 mL (n = 13) or 50 mL (n = 11) of 1.5% lidocaine plus epinephrine, or direct obturator nerve block with 10 mL of 2% lidocaine plus epinephrine (n = 20). After both direct obturator and 3-in-1 blocks, compound muscle action potential (CMAP) testing of the obturator nerve was performed at 1-10-s intervals for 10 min. In patients given direct obturator nerve block (n = 20), CMAP amplitude decreased by 88.8 +/- 21% (mean +/- SD) from baseline. In contrast, 3-in-1 block reduced the evoked CMAP amplitude by 7.4 +/- 19% (P < 0.05). Peak lidocaine plasma levels of 1.6 +/- 0.2 micro gram/mL (range 1.0-2.8 micro gram/mL) were reached 60-90 min after the block in those patients receiving 50 mL of local anesthetic. The 3-in-1 technique fails to predictably result in effective motor block of the obturator nerve and thus may not prevent inadvertent thigh adductor muscle contractions during transurethral surgery. A direct approach to the obturator nerve is significantly more effective in producing motor block, and even when given in larger than recommended dosages it results in subtoxic peak plasma lidocaine concentrations. (Anesth Analg 1995;81:529-33)

Pregnant patient with primary pulmonary hypertension : Inhaled pulmonary vasodilators and epidural anesthesia for cesarean delivery

Address reprint requests to Dr. Weiss: Department of Anesthesiology, University Hospital, Raemistr 100, CH-8091 Zurich, Switzerland. Address electronic mail to: branko.weiss@ifa.usz.ch plicated delivery of a neonate. She refused treatment at that time. During her second pregnancy, at 15 weeks’ gestation, Doppler echocardiography showed a right atrial diameter of 6.2 cm (normal diameter, 2.2-4.1 cm), a short-axis end-diastolic diameter of the right ventricle of 5.1 cm (normal, 1.9 4.0 cm), a right ventricle with eccentric hypertrophy and fractional area shortening of 3396, and a small, normally contracting left ventricle. The patient was lost to further follow-up examinations and reappeared at 31 weeks’ gestation, severely dyspneic at rest and with dilated neck veins and lower limb edema. Ultrasonograph showed a growth-retarded fetus. The patient’s systemic arterial pressure (AP) was 108/69 mmHg, with a regular heart rate of 94 beatshin. Electrocardiography showed a sinus rhythm, prominent P waves in V,-V,, and a partial right bundle branch block. Oxygen saturation by pulse oximetry (Sp,,) of 88% increased to more than 94% with supplemented nasal oxygen. Hemoglobin was 11.4 g/dl, and platelet count was 177 1030 /~ l . Radial artery and thermodilution pulmonary artery catheters were inserted to test the response to nitric oxide (NO) and to oxygen breathing at inspiratory fraction ( F I ~ ] ~ ) of 1.0. Nitric oxide (40 ppm) failed to improve pulmonary hemodynamics, but oxygen breathing slightly decreased pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) and the catheters were removed. Dalteparin (Fragmin; Pharm Upjohn, Stockholm, Sweden), a lowmolecular-weight heparin, was administered subcutaneously at 5,000 and 7,500 IU/day. .The patient received digoxin, magnesium for its tocolitic properties, and betamethasone at 31 weeks and 32 weeks of gestation to promote fetal lung maturation. Continued right-sided heart dilatation (atrial diameter = 6.3 cm, end-diastolic ventricular diameter = 5.4 cm) and a decrease of right ventricular fractional arrd shortening to 25?4 were found at 32 weeks’ gestation. Ultrasound biometry showed insufficient fetal growth, and the decision was made to proceed with cesarean delivery at 34 weeks’ gestation. In the operating room, the patient was placed in a supine position with left uterine displacement. Radial artery, thermodilution pulmonary artery, and lumbar epidural (L2-3) catheters were placed during local anesthesia. After baseline measurements, 6 I/min 0, by mask increased Sp,,, from 90 to 96%. The hemodynamic parameters, hemo

Intercostal Nerve Block for Lumpectomy: Superior Postoperative Pain Relief with Bupivacaine

STUDY OBJECTIVES To investigate whether equipotent doses of lidocaine and bupivacaine were equally effective for intercoastal nerve blockade (ICNB) and whether a lower amount of lidocaine would be comparably effective. To see whether plasma levels of lidocaine with and without epinephrine and of plain bupivacaine would reach toxic ranges. Finally, to evaluate the duration of postoperative analgesia following general anesthesia and regional anesthesia with two different local anesthetics. DESIGN Randomized, double-blind study, with control group administered general anesthesia. SETTING Gynecologic operating room of a university hospital. PATIENTS 48 adult ASA physical status I and II otherwise healthy patients undergoing lumpectomy. INTERVENTIONS 36 patients received ICNB of T3-T6 unilaterally using either 4 ml/segment of 1.5% lidocaine with epinephrine 3.75 micrograms/ml (n = 10, Group A), 4 ml/segment of 2% lidocaine with epinephrine 5 micrograms/ml (n = 13, Group B), or 4 ml/segment of plain 0.5% bupivacaine (n = 13, Group C). The control group consisted of 12 patients (Group D) who received a general anesthetic using propofol, alfentanil, and nitrous oxide in oxygen for induction and maintenance of anesthesia. MEASUREMENTS AND MAIN RESULTS In all three ICNB groups, the highest plasma concentrations were reached after 5 to 10 minutes following ICNB--i.e., a lidocaine plasma level of 2.77 +/- 0.5 micrograms/ml (mean +/- SEM) in Group A, a lidocaine plasma level of 2.78 +/- 0.2 micrograms/ml in Group B, and a bupivacaine plasma level of 1.44 +/- 0.2 micrograms/ml in Group C. There were no significant differences in plasma levels between 1.5% lidocaine and 2% lidocaine. For the first 90 minutes after surgery, higher postoperative pain scores were found in the control group than in the ICNB groups. Notably longer-lasting postoperative pain relief was achieved with plain bupivacaine. The number of women requiring postoperative analgesic medication, the time of first request, and the total amount of analgesic drugs administered during the 24 hours postoperatively were significantly lower in the regional anesthesia groups than in the general anesthesia group (p < 0.05). CONCLUSIONS ICNB is an alternative to general anesthesia for female breast surgery. Both lidocaine with epinephrine and plain bupivacaine in the doses used did not raise venous plasma concentrations to levels considered potentially toxic. With respect to duration of postoperative pain relief and analgesic drug request, the local anesthetics (in particular, bupivacaine) were found to be superior to general anesthesia.

Cyanotic congenital heart disease and pregnancy: Natural selection, pulmonary hypertension, and anesthesia

Pregnancy carries substantial maternal and fetal risks in patients with uncorrected or palliatively corrected cyanotic congenital heart disease (CHD). In tricuspid valve Ebsteins anomaly, pregnancy is well tolerated. Maternal mortality in tetralogy of Fallot seems to be less than 10%, but it exceeds 50% in Eisenmengers syndrome and primary pulmonary hypertension (PPH). Maternal hematocrit greater than 60%, arterial oxygen saturation lower than 80%, right ventricular hypertension, and syncopal episodes are poor prognostic signs. Maternal risk could be reduced by vaginal delivery. Continuous monitoring of arterial and central venous pressure, electrocardiography, and pulse oximetry are recommended for every anesthetic procedure. The use of a pulmonary artery catheter is controversial and probably should be avoided in parturients with cyanotic CHD or PPH. The choice of anesthetic technique and drugs per se is of secondary importance and should be governed by individual preferences. Titration of anesthetic drugs, general anesthesia with controlled ventilation, or, preferably, regional anesthesia with spontaneous breathing should be used cautiously to avoid worsening of the preexisting condition. Prevention of excessive erythrocytosis, volume and blood loss substitution, cardiocirculatory pharmacologic support, prophylaxis of infective endocarditis, and judicious use of anticoagulant drugs should be applied as indicated by the type and presentation of CHD. Poor outcome of pregnancy in PPH requires an early consideration of heart-lung or lung transplantation. Multidisciplinary team effort and prolonged monitoring in the intensive care unit are mandatory to ensure a favorable outcome for cyanotic CHD and PPH parturients.

Superior hemodynamics in left heart bypass without systemic heparinization

Open-chest left heart bypass was performed in 10 canine experiments (30 +/- 9 kg) by a servo controlled roller pump for 6 h at a pump flow of 50 ml/min per kg bodyweight. The surfaces of the tubing sets were either standard (with systemic heparinization) or with end-point attached heparin (no systemic heparin). Besides continuous monitoring of hemodynamics, a standard battery of blood samples was taken before bypass, after 10 min and every hour thereafter. There is no evidence of increased fibrin production in the group with end-point attached heparin surfaces perfused without systemic heparinization. Superior hemodynamics in left heart bypass performed without systemic heparinization appear to be due to improved hemostasis, reduced blood loss and therefore reduced transfusion requirements. Left heart bypass with heparin-coated equipment has been successfully used for resection of a thoracoabdominal aneurysm in six patients.

Perioperative course and recovery after heparin-coated cardiopulmonary bypass : Low-dose versus high-dose heparin management

OBJECTIVE To compare two heparin managements for a cardiopulmonary bypass (CPB) procedure with heparin-coated equipment. The hypothesis was that a lower heparin dose may reduce blood loss and homologous transfusion requirements and influence the speed of postoperative recovery. DESIGN Prospective, randomized, and open study. SETTING Operating room and intensive care unit in a university hospital. PARTICIPANTS Twenty-four patients undergoing first-time elective coronary artery surgery. INTERVENTIONS Heparin-coated CPB equipment (Duraflo II; Baxter-Bentley) was used in all patients. The study group (n = 12) received low-dose (100 IU/kg i.v. and 0 to 1,000 IU/L priming; target level of activated coagulation time [ACT] over 180 seconds during CPB; suction in a red cell washing device); and the control group (n = 12) received high-dose (300 IU/kg i.v. and 5,000 IU/L priming; ACT over 480 seconds; standard cardiotomy suction) heparin management. MEASUREMENTS AND MAIN RESULTS ACT remained above 200 seconds after the initial heparin dose in the study group for the CPB duration up to 99 minutes. In 11 of 12 patients in the control group, additional heparin was required during CPB. Total doses of heparin and protamine (mean 8,017 v 50,508 IU and 83 v 325 mg, respectively; p < 0.0001), volume of homologous blood transfusion (median 600 v 1450 mL; p < 0.025), and blood products exposure (median 0.5 v 5.0 units/patients; p < 0.05) were significantly lower in the study group. Postoperative chest drainage showed a trend to lower volume loss (median 705 v 930 mL; p < 0.08) in patients managed with low-dose heparin. Oxygenator resistance during CPB, perioperative laboratory analyses (oxygen and metabolic data, hematocrit, platelet count, prothrombin, thrombin, activated partial thromboplastin time, fibrinogen, D-dimers, creatine kinase, and myocardial band of creatine kinase concentration), fluid balance, and the time periods required for extubation, stay in the intensive care unit, and hospital discharge were not different between the groups. There were no evidences of myocardial infarction in any of 24 patients, and all recovered after the procedure. CONCLUSION Low-dose heparin management enabled uneventful procedures with heparin-coated CPB equipment, significantly decreased protamine and homologous blood requirements, but did not reduce chest drainage or influence the postoperative course and recovery in patients after coronary artery surgery.

The Time Course of Gastric pH Changes Induced by Omeprazole and Ranitidine: A 24-Hour Dose-Response Study

The time-course of the effects of single-dose acid-reducing therapy in surgical patients is not known. Therefore, a prospective, randomized trial compared the effects of single-dose administration of omeprazole or ranitidine on gastric pH in 52 patients undergoing lower abdominal surgery. The two drugs were administered intravenously in random fashion after placement of a gastric electrode for continuous 24-h pH monitoring. In patients receiving omeprazole 20 mg (n = 13) and 40 mg (n = 13), gastric pH >or=to 2.5 was achieved after a median of 80 (range 15-269) min and 40 (6-102) min (P = not significant [NS]), whereas in those receiving ranitidine 25 mg (n = 13) and 50 mg (n = 13), this pH was reached after a median of 32 (15-82) and 44 (16-84) min, respectively (P = NS). Over the first 24 h postoperatively, gastric pH remained less than 2.5 for a significantly longer time (1060 min vs 611 min), and more than 4.0 for a significantly shorter time (240 min vs 780 min) after omeprazole 20 mg than after ranitidine 50 mg. There were no other significant differences among treatment groups regarding the duration of gastric pH less than 2.5, between 2.5 and 4.0, and more than 4.0. In all treatment groups, the gastric pH returned to the baseline value of < 2.0 within 18 h. We conclude that when it is desired that gastric pH be more than 4.0 for at least 3 h, a single dose of ranitidine 25 mg or 50 mg should be administered 30-45 min prior to induction of anesthesia. (Anesth Analg 1995;80:975-9)