Safety of catheter-delivered plasmin in patients with acute lower extremity arterial or bypass graft occlusion: phase I results.

BACKGROUND: Current treatment of acute peripheral artery or bypass graft occlusion utilizes catheter-directed thrombolysis of a plasminogen activator (PA). Plasmin is a direct-acting thrombolytic with a striking safety advantage over PA in preclinical models. OBJECTIVES: To report the first use of purified plasmin for acute lower extremity arterial or bypass graft thrombosis in a phase I dose-escalation study of a catheter-delivered agent. METHODS: Eighty-three patients with non-embolic occlusion of infrainguinal native arteries or bypass grafts were enrolled (safety population) into seven sequential dose cohorts to receive 25-175 mg of plasmin by intrathrombus infusion over 5 h. Arteriograms were performed at baseline, 2 h, and 5 h, and subjects were monitored for 30 days for clinical outcomes and laboratory parameters of systemic fibrinolysis. RESULTS: Major bleeding occurred in four patients (4.8%), and minor bleeding alone in 13 (15.7%), with no trend towards more bleeding at higher dosages of plasmin. There was a trend towards lower plasma concentrations of fibrinogen, α(2) -antiplasmin and α(2) -macroglobulin with increasing doses of plasmin, but the nadir fibrinogen concentration was > 350 mg dL(-1) at the highest plasmin dose. Individual nadir values were above 200 mg dL(-1) in 82 of 83 subjects, and were not different in patients with or without bleeding. Thrombolysis (≥ 50%) occurred in 79% of subjects receiving 125-175 mg of plasmin, as compared with 50% who received 25-100 mg. CONCLUSIONS: Catheter-delivered plasmin can be safely administered to patients with acute lower extremity arterial occlusion at dosages of 25-175 mg.

The use of PDAs to collect baseline survey data: lessons learned from a pilot project in Bolivia.

We compared the use of personal digital assistants (PDAs) against the use of standard paper questionnaires for collecting survey data. The evaluation consisted of qualitative approaches to document the process of introducing PDAs. Fieldwork was carried out during June-July 2005 at 12 sites in Bolivia. Data collectors reacted positively to the use of the PDAs and noted the advantages and disadvantages of paper and PDA data collection. A number of difficulties encountered in the use of PDA technology serve as a warning for investigators planning its adoption. Problems included incompatible data files (which impeded the ability to interpret data), an inadequate back-up protocol, and lack of a good 'fit' between the technology and the study. Ensuring the existence of a back-end database, developing an appropriate and adequate back-up protocol, and assessing whether a technology 'fits' the project are important factors in weighing the decision to collect data using PDAs.

Creatinine clearance and adverse hospital outcomes in patients with acute coronary syndromes: findings from the global registry of acute coronary events (GRACE).

OBJECTIVE: To determine whether creatinine clearance at the time of hospital admission is an independent predictor of hospital mortality and adverse outcomes in patients with acute coronary syndromes (ACS). DESIGN: A prospective multicentre observational study, GRACE (global registry of acute coronary events), of patients with the full spectrum of ACS. SETTING: Ninety four hospitals of varying size and capability in 14 countries across four continents. PATIENTS: 11 774 patients hospitalised with ACS, including ST and non-ST segment elevation acute myocardial infarction and unstable angina. MAIN OUTCOME MEASURES: Demographic and clinical characteristics, medication use, and in-hospital outcomes were compared for patients with creatinine clearance rates of > 60 ml/min (normal and minimally impaired renal function), 30-60 ml/min (moderate renal dysfunction), and < 30 ml/min (severe renal dysfunction). RESULTS: Patients with moderate or severe renal dysfunction were older, were more likely to be women, and presented to participating hospitals with more comorbidities than those with normal or minimally impaired renal function. In comparison with patients with normal or minimally impaired renal function, patients with moderate renal dysfunction were twice as likely to die (odds ratio 2.09, 95% confidence interval 1.55 to 2.81) and those with severe renal dysfunction almost four times more likely to die (odds ratio 3.71, 95% confidence interval 2.57 to 5.37) after adjustment for other potentially confounding variables. The risk of major bleeding episodes increased as renal function worsened. CONCLUSION: In patients with ACS, creatinine clearance is an important independent predictor of hospital death and major bleeding. These data reinforce the importance of increased surveillance efforts and use of targeted intervention strategies in patients with acute coronary disease complicated by renal dysfunction.

Ciclo reprodutivo de Parauchenipterus striatulus (Pisces-Auchenipteridae) na represa de Riberäi das Lajes - RJ / Reproductive cycle of Parauchenipterus striatulus (Pesces-Auchenipteridae) in the Ribeiräo das Lajes reservoir - Brazil

Este trabalho teve como objetivo avaliar o ciclo reprodutivo do bagre de água doce Parauchenipterus striatulus, na represa de Ribeiräo das Lajes, Rio de Janeiro. Foram descritos aspectos morfológicos dos estádios de maturaçäo gonadal bem como variaçöes no índice gonadossomático, relaçäo peso: comprimento, fator de condiçäo gonadal. A amostragem dos peixes foi feita bimestralmente entre abril de 1996 e maio de 1997 com o uso de redes de espera de 100m de comprimento, 4m de altura e com malha entre 25 e 65mm de distância entrenós. Os 339 indivíduos capturados ao longo do período de amostragem corresponderam a 40 por cento do total de peixes. Cinco estádios de maturaçäo gonadal foram determinados por meio de análise macroscópica para ambos os sexos: imaturo, maturaçäo I, maturaçäo II, maduro, desovado (fêmeas) e esvaziado (machos). O índice gonadossomático foi mais elevado entre outubro e março para ambos os sexos, sugerindo amplo período de desova enquanto o fator de condiçäo atingiu seu máximo entre fevereiro a junho, mostrando uma relaçäo inversa entre essas duas características. A relaçäo peso-comprimento para machos foi de W=0,0095L3,0862 sobrescrito e fêmeas de W=0,0116L3,0126 sobrescrito, näo tendo sido encontradas diferenças significativas entre os coeficientes de alometria para ambos os sexos

Ciclo reprodutivo de Parauchenipterus striatulus (Pisces - Auchenipteridae) na represa de Ribeirão das Lajes - RJ

The objective of this work was to evaluate aspects related to the reproductive cycle of the armored catfish Parauchenipterus striatulus in Ribeirão das Lajes Reservoir, state of Rio de Janeiro, Brazil. Gonadal stage, morphology, variations in the gonadosomatic index, weight:length relationship, condition factor and gonadal condition were described. Fish sampling was carried out bi-monthly, between April 1996 and May 1997, using gill nets 100m long, 4m wide, and 25-65mm of mesh sizes gill nets. Three hundred and thirty-nine fishes, corresponding to 40% of the total number, were capture. Five maturation stages were determined by macroscopic analysis of both sexes: immature, mature I, mature II, ripe and spawned (females) or empty (males). The gonadosomatic index was higher from October to March for both sexes, suggesting an ample spawning period, while the condition factor was higher from February to June, showing an inverse relationship between these two characteristics. Weight:length relationship for males was W = 0.0095L3.0862 and for females W = 0.0116L3.0126, with no significant differences between sexes in the allometric coefficient.

Este trabalho teve como objetivo avaliar o ciclo reprodutivo do bagre de água doce Parauchenipterus striatulus, na represa de Ribeirão das Lajes, Rio de Janeiro. Foram descritos aspectos morfológicos dos estádios de maturação gonadal bem como variações no índice gonadossomático, relação peso:comprimento, fator de condição e condição gonadal. A amostragem dos peixes foi feita bimestralmente entre abril de 1996 e maio de 1997 com o uso de redes de espera de 100m de comprimento, 4m de altura e com malha entre 25 e 65mm de distância entrenós. Os 339 indivíduos capturados ao longo do período de amostragem corresponderam a 40% do total de peixes. Cinco estádios de maturação gonadal foram determinados por meio de análise macroscópica para ambos os sexos: imaturo, maturação I, maturação II, maduro, desovado (fêmeas) e esvaziado (machos). O índice gonadossomático foi mais elevado entre outubro e março para ambos os sexos, sugerindo amplo período de desova enquanto o fator de condição atingiu seu máximo entre fevereiro e junho, mostrando uma relação inversa entre essas duas características. A relação peso-comprimento para machos foi de W= 0,0095L3,0862 e fêmeas de W= 0,0116L3,0126, não tendo sido encontradas diferenças significativas entre os coeficientes de alometria para ambos os sexos.

[Gender differences and diabetic status in the relationship of blood apolipoprotein C-III, free fatty acids and triglycerides in subjects at risk for glucose intolerance]. / Diferencias según sexo y estado diabético en la relación entre apolipoproteína C-III y ácidos grasos libres con los triglicéridos séricos en sujetos a riesgo para intolerancia a la glucosa.

Insulin resistance and hyperinsulinemia can induce overproduction of triglyceride (TG) rich VLDL in the liver by increasing the availability of free fatty acids (FFA). Conversely, apolipoprotein C-III (apoC-III) is an inhibitor of the catabolism of TG-rich lipoproteins. To explore the relationship among FFA, apo C-III and TG in hyperinsulinemic subjects, we studied 103 individuals (63 women and 40 men) with a body mass index (BMI) 25 Kg/m2: 59 subjects with normal glucose tolerance (NGT), and 44 with newly diagnosed type 2 diabetes. After adjustment for age, BMI, fasting insulin and TG, FFA were significantly higher in women than in men and in subjects with diabetes compared with NGT. Subjects with diabetes had higher apo C-III levels compared to NGT, adjusted for age, sex and BMI, and that was largely accounted for by differences in insulin and TG levels. In addition, regression analysis in subjects with diabetes showed that TG were strongly associated with apo C-III in both men and women (r = 0.90 and 0.79, respectively; p < 0.001), while the association tended to be smaller between TG and FFA (r = 0.48, p < 0.05 in men and r = 0.45, p = 0.06 in women). Conversely, in individuals with NGT fasting TG was strongly associated with apo C-III in men (r = 0.83, p < 0.01) but not with FFA, while in women TG was associated with FFA (r = 0.39, p < 0.05) but not with apo C-III. In summary, elevated apo C-III was a predominant factor associated with elevated TG levels in NGT men and all subjects with type 2 diabetes, while FFA were more closely related with TG levels in NGT women.

Insulin response in a triethnic population: effects of sex, ethnic origin, and body fat. Miami Community Health Study.

OBJECTIVE: To assess sex and ethnic differences in hyperinsulinemia/insulin resistance and to examine the impact of percent body fat on such differences. RESEARCH DESIGN AND METHODS: A cross-sectional epidemiological study was performed in a normoglycemic population of African-Americans (n = 159), Cuban Americans (n = 128), and non-Hispanic whites (n = 207) who resided in Dade County, Florida, from 1990 to 1995. The insulin area under the curve (AUC) in response to a standard 75-g oral glucose tolerance test (OGTT) was used as an indicator of hyperinsulinemia/insulin resistance. Analysis of covariance was performed to compare sex and ethnic differences in the insulin AUC. Multiple linear regression was used to evaluate the independent correlates of the insulin AUC. RESULTS: After covariate adjustment for percent body fat, men displayed a significantly higher insulin AUC than did women (P < 0.001). African-Americans and Cuban-Americans each had a significantly higher insulin AUC than did non-Hispanic white participants (P = 0.01). Alcohol consumption was inversely related to AUC (P = 0.04). CONCLUSIONS: Despite the greater percentage of body fat in women, the insulin AUC was similar in women and men. After adjustment for the sex difference in percent body fat, women displayed a lower insulin AUC than did men, indicating enhanced insulin sensitivity. These differences by sex and ethnicity in insulin resistance are consistent with established differences in heart-disease risk (i.e., higher in men and African-Americans) and suggest that hyperinsulinemia/insulin resistance may partly underlie such differences.

Randomized, multicenter trial of inhaled nitric oxide and high-frequency oscillatory ventilation in severe, persistent pulmonary hypertension of the newborn.

BACKGROUND: Although inhaled nitric oxide (iNO) causes selective pulmonary vasodilation and improves oxygenation in newborn infants with persistent pulmonary hypertension, its effects are variable. We hypothesized (1) that the response to iNO therapy is dependent on the primary disease associated with persistent pulmonary hypertension of the newborn (PPHN) and (2) that the combination of high-frequency oscillatory ventilation (HFOV) with iNO would be efficacious in patients for whom either therapy alone had failed. METHODS: To determine the relative roles of iNO and HFOV in the treatment of severe PPHN, we enrolled 205 neonates in a randomized, multicenter clinical trial. Patients were stratified by predominant disease category: respiratory distress syndrome (n = 70), meconium aspiration syndrome (n = 58), idiopathic PPHN or pulmonary hypoplasia (excluding congenital diaphragmatic hernia) ("other": n = 43), and congenital diaphragmatic hernia (n = 34); they were then randomly assigned to treatment with iNO and conventional ventilation or to HFOV without iNO. Treatment failure (partial pressure of arterial oxygen [PaO2] < 60 mm Hg) resulted in crossover to the alternative treatment; treatment failure after crossover led to combination treatment with HFOV plus iNO. Treatment response with the assigned therapy was defined as sustained PaO2 of 60 mm Hg or greater. RESULTS: Baseline oxygenation index and PaO2 were 48 +/- 2 and 41 +/- 1 mm Hg, respectively, during treatment with conventional ventilation. Ninety-eight patients were randomly assigned to initial treatment with HFOV, and 107 patients to iNO. Fifty-three patients (26%) recovered with the initially assigned therapy without crossover (30 with iNO [28%] and 23 with HFOV [23%]; p = 0.33). Within this group, survival was 100% and there were no differences in days of mechanical ventilation, air leak, or supplemental oxygen requirement at 28 days. Of patients whose initial treatment failed, crossover treatment with the alternate therapy was successful in 21% and 14% for iNO and HFOV, respectively (p = not significant). Of 125 patients in whom both treatment strategies failed, 32% responded to combination treatment with HFOV plus iNO. Overall, 123 patients (60%) responded to either treatment alone or combination therapy. By disease category, response rates for HFOV plus iNO in the group with respiratory syndrome and the group with meconium aspiration syndrome were better than for HFOV alone or iNO with conventional ventilation (p < 0.05). Marked differences in outcomes were noted among centers (percent death or treatment with extracorporeal membrane oxygenation = 29% to 75%). CONCLUSIONS: We conclude that treatment with HFOV plus iNO is often more successful than treatment with HFOV or iNO alone in severe PPHN. Differences in responses are partly related to the specific disease associated with PPHN.

Transdermal clonidine for ameliorating tamoxifen-induced hot flashes.

PURPOSE: To determine the efficacy of transdermal clonidine for alleviating tamoxifen-induced hot flashes in women with a history of breast cancer. PATIENTS AND METHODS: A randomized, double-blind, crossover design was used in this prospective study. Women with a history of breast cancer who were receiving tamoxifen and suffering from hot flashes were potentially eligible for this protocol study. RESULTS: Clonidine did reduce hot-flash frequency to a degree that was statistically impressive (P < .0001), but clinically moderate (20% reduction from baseline). It also decreased hot-flash severity (P = .02, 10% reduction from baseline). Clonidine was related to increased mouth dryness (P < .001), constipation (P < .02), itchiness under the patch (P < .01), and drowsiness (P < .05). CONCLUSION: Better means are needed to alleviate hot flashes among patients in whom estrogen therapy is contraindicated.

Variable phenotypes in velocardiofacial syndrome with chromosomal deletion.

Velocardiofacial syndrome (VCF) has overlapping features with DiGeorge sequence; both result from a developmental field defect and probably represent contiguous gene deletion syndromes. The association of chromosome 22q11 deletion with DiGeorge sequence led us to do molecular analysis of chromosome 22 in 18 patients with VCF, who ranged in age from 6 to 42 years. All 18 patients had monosomy for the chromosome region 22q11. Retrospectively, we correlated the presence of the deletion with various clinical findings: 100% had cleft palate, 67% the facial phenotype, 83% cardiac disease, 94% learning disabilities, 70% ophthalmologic findings, 50% short stature, 22% psychiatric disorders, and 17% hypocalcemia. Both severely phenotypically affected and mildly affected patients had the deletion. These findings stress the importance of continued surveillance of all patients with VCF for the many medical problems that may not be present at initial diagnosis. We conclude that the presence of the gene deletion does not predict the phenotypic expression in VCF. Further studies to characterize the size of the gene deletion may facilitate better prediction of the phenotype.

Comparison of the lipid profiles of Cubans and other Hispanics with non-Hispanics.

We compared the plasma lipid profiles of Cuban Americans and other Hispanic-American subgroups with those of non-Hispanics. High-density lipoprotein cholesterol levels were lower and triglyceride levels were higher when Hispanic women were compared with non-Hispanic women, and this pattern was also apparent for men. The lower high-density lipoprotein cholesterol and higher triglyceride levels were consistent for both Cuban and non-Cuban Hispanics. There were higher waist-hip ratios and insulin levels in both Hispanic men and women. When allowances were made for these attributes in covariance analyses, the lipid differences were markedly diminished. These data suggest the lower high-density lipoprotein cholesterol and higher triglyceride levels are consistent across Hispanic subgroups and that this lipid pattern may be attributable at least in part to increased insulin resistance in Hispanics.

Bolus versus infusion regimens of etoposide and cisplatin in treatment of non-small cell lung cancer: a study of the North Central Cancer Treatment group.

In an effort to test clinically the hypothesis that the duration of cellular exposure to etoposide (VP-16) and cisplatin (CDDP) is an important determinant of cytotoxicity, we performed a phase III randomized trial comparing an outpatient bolus regimen of combined VP-16 and CDDP with a sequential infusion over 72 hours of these same two drugs. All patients had stage IV non-small cell lung cancer, and survival was the primary end point. Of 113 patients randomly allocated to the study, 108 were assessable for response, survival, and toxicity. A major response was observed in 20 (37%) of 54 patients on the bolus regimen and in 16 (30%) of 54 patients receiving infusion therapy. The median time to progression was 61 and 88 days for bolus and infusion therapy, respectively. The median survival time was 148 and 157 days, respectively (P = .71). Study results were not consistent with the possibility that infusion therapy could be associated with a 50% improvement in median survival, i.e. from 5 months to 7 1/2 months. Toxicity was primarily myelosuppression and was significantly greater with the infusion regimen. We conclude that infusion therapy as tested in this protocol with VP-16 and CDDP does not offer any advantage in response rate, time to disease progression, or survival as compared with bolus therapy. In addition, infusion therapy is associated with a greater degree of neutropenia and more treatment-related deaths.

Pulmonary function in preterm infants whose lungs were ventilated conventionally or by high-frequency oscillation.

To test the hypothesis that high-frequency ventilation may reduce the risk of barotrauma and thus the incidence of chronic pulmonary damage in preterm infants who need mechanical ventilation, we measured lung function before discharge in 53 infants who needed mechanical ventilation on the first day after birth and were randomly assigned to receive intermittent mandatory ventilation (n = 26) or to receive high-frequency oscillatory ventilation (n = 27). There were no significant differences between the groups in birth weight (mean +/- SD: 1010 +/- 240 vs 1030 +/- 230 gm), gestational age (29.1 +/- 2.0 vs 28.9 +/- 2.1 weeks), initial ventilatory support (mean airway pressure 7.2 +/- 1.8 vs 8.1 +/- 2.1 cm H2O; FiO2 0.62 +/- 0.24 vs 0.75 +/- 0.22), duration of mechanical ventilation (median (range): 6 (1 to 61) vs 10 (1 to 50) days) and duration of oxygen therapy (13 (1 to 109) vs 27 (4 to 227) days) for the intermittent mandatory ventilation group and the high-frequency oscillatory ventilation group, respectively. At the time of testing, weight was 1830 +/- 340 vs 1830 +/- 290 gm, and age was 68 +/- 24 vs 70 +/- 31 days. Respiratory flows were determined by pneumotachygraphy, esophageal pressure through a water-filled feeding tube, and functional residual capacity by N2 washout. Both groups had abnormal lung function with decreased lung compliance (1.65 +/- 0.51 vs 1.54 +/- 0.36 ml/cm H2O) and elevated pulmonary resistance (102 +/- 24 vs 107 +/- 36 cm H2O/L/sec). Functional residual capacity was in the normal range (30.6 +/- 6.0 vs 28.2 +/- 10.7 ml) in both groups. There were no significant differences in lung function between the two treatment groups. These results do not support the hypothesis that high-frequency oscillatory ventilation reduces the risk of lung damage in preterm infants.

Autosomal recessive inheritance in the Setleis bitemporal 'forceps marks' syndrome.

We present the clinical findings in two children with the Setleis bitemporal "forceps marks" syndrome. The striking features include the following: (1) bitemporal scarring, an anomaly that resembles forceps marks; (2) periorbital puffiness with wrinkling of the skin; (3) abnormalities of the eyebrows; (4) anomalies of the eyelashes; (5) flattening of the nasal bridge with a bulbous nasal tip; (6) increased mobility of the skin, associated with severely redundant facial soft tissue; and (7) normal growth and development. The evidence that suggests that this unusual syndrome is inherited in an autosomal recessive fashion includes the following: (1) seven of the patients have come from the relatively isolated towns of San Sebastian and Aguadilla in Puerto Rico; (2) two sets of affected siblings have been described, and, in both cases, the siblings' parents were normal; and (3) one of the children described herein is the product of a consanguineous mating. Although the pathogenetic mechanism is unknown, Setleis syndrome is clearly inherited as an autosomal recessive trait.

Gas trapping with high-frequency ventilation: jet versus oscillatory ventilation.

Gas trapping was evaluated during high-frequency jet ventilation (HFJV) and high-frequency oscillatory ventilation (HFOV) in nine adult rabbits under basal conditions and after instillation of a mixture of 20% human meconium (2 mL/kg). The anesthetized animals underwent tracheostomy and were placed inside a body plethysmograph. Respiratory compliance and resistance were calculated from airway pressure and simultaneous flow, and volume was measured with a pneumotachograph. Gas trapping was measured as the change in volume observed in the plethysmograph after clamping the jet or the oscillatory line at respiratory rates of 10 and 15 Hz and tidal volumes of 1.0 and 2.0 mL/kg. Mean airway pressure was similar with both ventilators. Inspiratory/expiratory ratios were 1:4 at 10 Hz and 1:2 at 15 Hz with HFJV, and 1:1 during HFOV. Under all conditions, gas trapping was significantly greater with HFJV than with HFOV. More gas trapping was observed with higher tidal volume (2 mL/kg) and respiratory rate (15 Hz) during HFJV, before and after meconium instillation. After meconium instillation, gas trapping during HFJV at 15 Hz and tidal volume 2 mL/kg decreased significantly (32.7 +/- 10.4 to 24.9 +/- 10.3; P less than 0.05), compared with basal conditions. This finding may be explained by the shorter time constant of the respiratory system after meconium instillation (0.118 vs 0.083 seconds, P less than 0.01). Thus gas trapping was significantly greater with HFJV than with HFOV, a difference most likely related to the active expiratory phase of HFOV.

Use of barbiturate therapy in severe perinatal asphyxia: a randomized controlled trial.

The possible cerebral sparing effect of thiopental was evaluated in 32 severely asphyxiated neonates randomly assigned to either a thiopental treatment or control group. All infants had neurologic manifestations of asphyxia and required assisted ventilation. Thiopental was begun at a mean age of 2.3 hours and was given as a constant infusion that delivered 30 mg/kg over 2 hours. Treatment was continued at a lower dose for 24 hours. Seizure activity occurred in 76% of infants given thiopental and 73% of control infants at a mean age of 1.5 and 2.5 hours, respectively. Although initial arterial blood pressure was similar in both groups, hypotension occurred in 88% of treated and 60% of control infants. The amount of blood pressure support required was significantly greater (P less than 0.005) in the thiopental treatment group. Three infants died in the control group, and five in the treatment group. Developmental assessment was performed at a minimum of 12 months of age in 22 infants. There were no significant differences in neurologic, cognitive, or motor outcome between groups. Deteriorating performance over time was a consistent trend in both groups. These findings indicate that treatment of severe perinatal asphyxia with thiopental does not appear to have a cerebral sparing effect and may be associated with significant arterial hypotension.

Further delineation of Weaver syndrome.

Seven new cases of Weaver syndrome are described, including the first reported case in an adult. Overgrowth is usually but not always present. The combination of characteristic facies and developmental delay, with the peculiar radiographic findings of accelerated dysharmonic osseous maturation and splaying of the distal long bones, is diagnostic of Weaver syndrome.

Conventional vs high-frequency jet ventilation in a piglet model of meconium aspiration: comparison of pulmonary and hemodynamic effects.

The pulmonary and cardiovascular effects of high-frequency jet (HFJV) and conventional (CV) ventilation were evaluated in a piglet model of meconium aspiration. A mixture of 20% human meconium and 0.9% saline solution was instilled deep into the trachea of 10 piglets, after which either HFJV or CV was administered for 4 hours. Arterial blood gases, cardiac output, mean pulmonary and systemic arterial pressures, pulmonary and systemic vascular resistances, and pulmonary mechanics were compared between groups. During the 4 hours of ventilation, PaO2 and PaCO2 were not statistically different between groups. The peak inspiratory pressure necessary to maintain PaCO2 in the preset range was approximately half as much in the HFJV group as in the CV group (P less than 0.002). Mean airway pressure was lower in the HFJV group only during the second hour (P less than 0.03). Cardiac output, mean aortic and pulmonary artery pressures, systemic and pulmonary vascular resistance, dynamic lung compliance, and pulmonary resistance were not statistically different between groups. Our results suggest that HFJV may be more effective than CV in the early stages of meconium aspiration syndrome because HFJV allows more efficient ventilation and adequate oxygenation at lower peak inspiratory pressures.