Use of a continuous glucose sensor in an extracorporeal life support circuit

BACKGROUND

Standard care for infants on extracorporeal life support (ECLS) relies on intermittent measurement of blood glucose (BG); however, this can lead to significant changes in BG that go unrecognized for several hours. The present study was designed to assess performance and clinical applicability of a subcutaneous glucose sensor technology modified for use as a blood-contacting sensor within the ECLS circuit.

METHODS

Twelve children, aged 3 years or less, requiring ECLS support were studied. Three continuous glucose sensors (Medtronic MiniMed) were inserted into hubs placed in line with the ECLS circuit. Blood glucose was assessed with a laboratory analyzer (BG(LAB); Bayer Rapidlab 860) approximately every 5 h (mean 4.9 ± 3.3 h) with more frequent samples obtained with a bedside monitor (HemoCue) as needed. Sensor current (I(SIG)) was transmitted to a laptop computer and retrospectively calibrated using BGLAB. Sensor performance was assessed by mean absolute relative difference (MARD), linear regression slope and intercept, and correlation, all with BGLAB as reference.

RESULTS

The BGLAB averaged 107.6 ± 36.4 mg/dl (mean ± standard deviation) ranging from 58 to 366 mg/dl. The MARD was 11.4%, with linear regression slope (0.86 ± 0.030) and intercept (9.0 ± 3.2 mg/dl) different from 1 and 0, respectively (p < .05), and correlation (r² = 0.76; p < .001). The system was not associated with any adverse events, and placement and removal into the hubs was easily accomplished. Instances in which more frequent BG values were obtained using a bedside HemoCue (BGHEMO) monitor showed the sensor to respond rapidly to changes.

CONCLUSIONS

We conclude that continuous sensors can be adapted for use in an ECLS circuit with accuracy similar to or better than that achieved with the subcutaneous site. Continuous glucose monitoring in this population can rapidly detect changes in BG that would not otherwise be observed. Further studies will be needed to assess the benefit of continuous glucose monitoring in this population.

Thoracoscopic repair of congenital diaphragmatic hernia: intraoperative ventilation and recurrence

INTRODUCTION

Thoracoscopic repair of congenital diaphragmatic hernia (CDH) has been described, but its efficacy and safety have not been validated. The aim was to compare our experience of thoracoscopy with laparotomy repair.

METHODS

After ethics approval, we reviewed the notes of neonates with CDH operated in our institution between 2003 and 2008. Two historical groups were compared: infants who underwent laparotomy (2003-2008) or thoracoscopy (2007-2008). Data were compared by t test or Mann-Whitney tests.

RESULTS

Thirty-five children had open repair of CDH, and 13 had thoracoscopic repair. Groups were homogeneous for age and weight. Five (38%) neonates who had thoracoscopy were converted to open for surgical difficulties (n = 4) and O(2) desaturation (n = 1). Patch repair was used in 12 (34%) open and 6 (46%) thoracoscopic repairs. End-tidal CO(2) was significantly elevated during thoracoscopy, but this was not reflected in arterial CO(2) or pH. There were 3 (8%) recurrences after open repair and 2 (25%) after thoracoscopy (P = .19).

CONCLUSION

Thoracoscopic repair of CDH is feasible. Arterial blood gases should be closely monitored. Despite higher EtCO(2), conversion to open was mainly because of difficult repair. A randomized trial is necessary to assess the effect of thoracoscopy on ventilation and recurrences.

Serum monocyte chemotactic protein-1 levels in congenital diaphragmatic hernia

To measure serum monocyte chemotactic protein-1 (MCP-1) in patients with congenital diaphragmatic hernia (CDH) and investigate its relationship to the development of persistent pulmonary hypertension (PPH). Serum MCP-1 was measured in 13 neonates with high risk for CDH at the time of diagnosis and postoperatively, and in five age-matched controls using an ELISA system. The 13 CDH subjects were divided into four groups according to the presence of PPH and outcome. Group I (severe-pre group): subjects with severe PPH who died prior to surgery (n = 5); Group II (mild-pre group): subjects with mild PPH controlled by medications (n = 8); Group IIa (severe-post group): subjects who subsequently developed severe PPH postoperatively and died (n = 3); and Group IIb (mild-post group): subjects who continued to have mild PPH controlled by medications. We also examined nitrofen-induced hypoplastic lungs from five rat fetuses with CDH and five control lung specimens for MCP-1 using immunohistochemistry. Mean serum MCP-1 in Group I was (1038.0 +/- 95.8 pg/ml), which was significantly higher than Group II (444.9 +/- 39.7 pg/ml) (P < 0.0001) and controls (147.3 +/- 11.3 pg/ml) (P < 0.0001). Postoperatively, Group IIa was significantly higher than Group IIb from 24 to 120 h postoperatively (P < 0.001). In Group IIb serum MCP-1 did not rise at all between 24 and 120 h postoperatively. Hypoplastic fetal rat CDH lungs had strong expression of MCP-1 compared with control lungs. Up-regulated expression and high circulating levels of MCP-1 in CDH patients with PPH suggest that MCP-1 may play a role in the development of PPH in CDH.

Administration of prenatal betamethasone suppresses the adrenal-hypophyseal axis in newborns with congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a condition that is characterized by pulmonary hypoplasia and pulmonary hypertension. Prenatal betamethasone often is administered to fetuses with CDH to improve pulmonary function. In this study, the authors investigate the possible role of the adrenal-hypophyseal axis in CDH in an animal model and subsequently in human infants with CDH.

METHODS

Twin fetal sheep underwent creation of DH or a sham thoracotomy, and levels of plasma and lung ACTH and plasma cortisol were compared. For the human studies, plasma levels of ACTH, cortisol, and DHEA were measured in cord blood samples collected from 9 CDH (5 that received prenatal betamethasone) and compared with those of 14 normal newborns. In both studies, ACTH and cortisol levels were determined by radioimmunoassay (RIA). Human (DHEA) levels were determined by ELISA.

RESULTS

Plasma ACTH and cortisol levels were elevated in fetal DH sheep compared with sham-operated controls; however, levels of ACTH in lung tissues were not different. Human newborns with CDH who have been exposed to prenatal steroids have significantly lower plasma ACTH, cortisol, and DHEA levels than normal newborns and CDH newborns not exposed to prenatal betamethasone.

CONCLUSIONS

In an ovine model of CDH, the adrenal-hypophyseal axis appears up-regulated in DH fetuses compared with sham-operated animals. Conversely, the adrenal-hypophyseal axis in human CDH newborns appears normal but is suppressed by the administration of prenatal betamethasone.

Factors influencing survival in newborns with congenital diaphragmatic hernia: the relative role of timing of surgery

PURPOSE

Controversy persists regarding the factors influencing survival in patients with congenital diaphragmatic hernia (CDH), in particular, the role of timing of surgery. The authors therefore sought to determine such factors and to assess the relative role of timing of surgery on outcome.

METHODS

All CDH newborns 1991 through 2002 (n = 111) were divided into those undergoing repair before ("early" n = 35), or after ("late" n = 76) 48 hours. A multivariate analysis was performed to determine the relative impact of various factors on survival rate.

RESULTS

Overall survival rate was 64%. There was no effect on survival of heart rate, temperature, systolic blood pressure, age, extracorporeal membrane oxygenation use, mesh use, infections, or intracranial hemorrhage, and there was no difference between early (68%) or late (62%) repair (P =.2). Initial pCO2 greater than 50, pO2 less than 40, cardiac defects, or renal failure significantly decreased survival rate.

CONCLUSIONS

Significant factors influencing survival rate in patients with CDH include cardiac defects, renal failure, and the initial blood gases and not the timing of surgery. CDH repair should be based on the optimization of clinical parameters as opposed to a specific time period to improve outcome.

Impact of a current treatment protocol on outcome of high-risk congenital diaphragmatic hernia

BACKGROUND

There is considerable debate regarding the optimal management of congenital diaphragmatic hernia (CDH) in high-risk infants (those cases presenting with respiratory distress within 2 hours of birth or those diagnosed prenatally). The aim of this study was to analyze patient outcomes using a new treatment protocol for CDH in a tertiary care non-extracorporeal membrane oxygenation (ECMO) neonatal unit.

METHODS

The records of 78 consecutive neonates with CDH presenting to Bambino Gesù Children's Hospital from 1996 to 2001 were analyzed retrospectively. Of these infants, 70 high-risk patients were identified (prenatal diagnosis or respiratory distress requiring intubation and assisted ventilation within 2 hours after birth), regardless of associated anomalies, medical condition on presentation, or degree of pulmonary hypoplasia. A prenatal diagnosis was made in 46 of 70 (66%) patients. Associated lethal malformations were present in 6 of the children (8.5%). The patients were placed in 3 historical groups: group 1, 19 patients from 1996 to 1997, group 2, 22 patients from 1998 to 1999, and group 3, 29 patients from 2000 to 2001. In the first 2 groups, a new protocol was introduced using inhaled nitric oxide (iNO) and high-frequency oxygen ventilation (HFOV). In the third group, gentle ventilation and permissive hypercarbia were also used routinely. Mortality and severe morbidity--defined as O2 requirement at discharge, need for a tracheostomy, neurologic impairment, or bilateral hearing loss-were evaluated when the patients were at 6 months old. Univariate analysis was performed.

RESULTS

The 3 groups were comparable with respect to predictive risk factors such as side of hernia, prenatal diagnosis, polyhydramnios, stomach and liver in the thorax, associated lethal malformations, and patch. Overall survival rate significantly increased from 47% (9 of 19) in group 1 and 50% (11 of 22) in group 2 to 90% (26 of 29) in group 3 (P =.02). None of the 19 patients in group 1 had severe morbidity compared with 2 of 22 (9%) patients in group 2 and 2 of 29 (7%) patients in group 3. Hearing loss was observed in 4 patients. Mortality rate and preoperative pneumothorax significantly decreased in group 3 compared with groups 1 and 2 (P =.03 and P =.00, respectively).

CONCLUSIONS

(1) The application of new treatment protocol for CDH, using gentle ventilation and permissive hypercarbia, produced a significant increase in survival with concomitant decrease in morbidity. (2) The rate of pneumothorax was significantly decreased by the introduction of permissive hypercarbia and gentle ventilation. (3) As more infants survive CDH without the use of ECMO, severe long-term sequelae of CDH can be recognized in these children.

Increased levels of circulating adhesion molecules in neonates with congenital diaphragmatic hernia complicated by persistent pulmonary hypertension

The aim of this study was to determine circulating levels of adhesion molecules in serum from patients with congenital diaphragmatic hernia (CDH) to investigate the relationship between soluble ICAM-1, ELAM-1, and VCAM-1 liberated by activated vascular endothelium and the development of persistent pulmonary hypertension (PPH) in patients with CDH. We measured serum levels of ICAM-1, ELAM-1, and VCAM-1 in 20 high-risk neonates with CDH at the time of diagnosis (11 with PPH and 9 without PPH) and 7 age-matched controls using ELISA system. We further examined the lungs of 5 patients with CDH complicated by PPH who died during resuscitation and stabilization, and three control lung specimens for the expression of adhesion molecules using immunohistochemistry. The mean serum ICAM-1 levels in CDH patients with PPH (227.0+/-98.9 ng/ml) were increased compared with levels in CDH patients without PPH (140.29+/-37.4 ng/ml; p<0.05) and controls (130.0+/-23.8 ng/ml; p<0.05). Mean serum ELAM-1 levels in CDH patients with PPH (116.5+/-19.2 ng/ml) were significantly increased compared with levels in CDH patients without PPH (79.3+/-27.9 ng/ml; p<0.01) and controls (58.4+/-14.5 ng/ml; p<0.001). Mean serum VCAM-1 levels in CDH patients with PPH (1596.9+/-460.4 ng/ml) were significantly higher compared with levels in CDH patients without PPH (1069.3+/-444.6 ng/ml; p<0.01) and controls (838.0+/-171.2 ng/ml; p<0.001). But serum adhesion molecule levels in CDH patients without PPH were no different from controls statistically. Pulmonary vascular endothelial cells from CDH lung with PPH had strong expression of adhesion molecules compared with controls. Up-regulated expression of adhesion molecules on the endothelium of pulmonary vessels and high circulating levels of adhesion molecules in CDH patients with PPH suggest that adhesion molecules may play a role in the development of PPH in CDH.

Is adrenomedullin involved in the pathophysiology of persistent pulmonary hypertension of the newborn?

Although adrenomedullin (ADM) is a potent vasodilating peptide reported to play a possible role in the mechanisms of fetal lung differentiation and maturation, the ADM blood level in fetuses and in neonates with persistent pulmonary hypertension (PPHN) and pulmonary hypoplasia is not known. Therefore, we examined 15 patients with PPHN: 10 with congenital diaphragmatic hernia, four with congenital cystic adenomatoid malformation of the lung, and one with misalignment of pulmonary vessels with alveolar capillary dysplasia. Eight surgical patients with neonatal conditions such as intestinal atresia served as controls. Blood samples were drawn from the umbilical artery and vein at birth, and arterial blood was drawn from patients with PPHN on the 3rd and 6th days after birth. Plasma levels of ADM were measured by radiometric assay. Plasma levels of ADM in the umbilical artery and vein were elevated in patients with PPHN compared with controls, and in all groups the levels in the umbilical vein were higher than those in the umbilical artery. The arterial levels in patients with poor prognoses were elevated on the 3rd and 6th days after birth compared with those in survivors. These results indicate that ADM may be involved in the pathophysiology of PPHN and in the mechanisms of lung differentiation and/or maturation.

Prenatal sonographic chest and lung measurements for predicting severe pulmonary hypoplasia in left-sided congenital diaphragmatic hernia

To assess the prenatal evaluation of lung hypoplasia in congenital diaphragmatic hernia (CDH), we attempted to measure the right lung area/thorax area ratio (rLT ratio) in normal fetuses and in seven cases of left-sided CDH. In addition, we analyzed early neonatal blood gas data, which were compared with the prenatal evaluation. The rLT ratio was significantly (p<0.05) higher in normal fetuses (0.27+/-0.02) than in CDH (0.14+/-0.18). The values of PaO(2), arterial-alveolar oxygen difference (A-aDO(2)) and oxygenation index (OI) showed no significant relationship with the rLT ratio in CDH at the early neonatal period. Three infants with CDH survived and showed significant higher values of rLT ratio compared with those in nonsurvived infants (p<0.05). All of the rLT ratios in nonsurvived infants were <0.11. PaO(2) at the early neonatal period was significantly (p<0.05) higher, and both A-aDO(2) and OI were significantly (p<0.05) lower in survived infants than in nonsurvived infants. These results indicated that prenatal evaluation of rLT ratio is useful to predict the severity of lung hypoplasia in infants with left-sided CDH, and blood gas analysis at early neonatal period is also useful to predict the neonatal outcome.

Multicenter analysis of platelet transfusion usage among neonates on extracorporeal membrane oxygenation

OBJECTIVE

Multiple platelet transfusions are invariably given to neonates on extracorporeal membrane oxygenation (ECMO), and no alternative to repeated transfusions exists. Before any alternatives, such as administration of thrombopoietic stimulators, could be contemplated, data regarding the number of platelet transfusions received by neonatal ECMO patients is needed, and the mechanisms that cause the thrombocytopenia of these patients must be better defined. As a step toward determining this, we analyzed the use of platelet transfusions in this group of neonates. We conducted a historic cohort study of neonates who were treated with ECMO to determine the number of platelet units received as a function of 1) days on ECMO, 2) medical diagnosis for which ECMO was instituted, and 3) type of ECMO used (venovenous [VV] vs venoarterial [VA]).

METHODS

We reviewed the hospital records of all neonates who were admitted to the neonatal intensive care units at Shands Children's Hospital, Arnold Palmer Hospital for Children and Women, and Tampa General Hospital and treated with ECMO between January 1, 1995, and June 30, 2000. Data were expressed as the number of platelet transfusions versus number of days on ECMO, diagnosis for which ECMO was instituted, and type of ECMO used.

RESULTS

Of the 234 ECMO patients, 81 were placed on VV, 138 were placed on VA, and 15 were converted from VV to VA. The average number of platelet transfusions received per day was 1.3 and varied by diagnosis and by type of ECMO. Neonates with meconium aspiration and sepsis required more platelet transfusions per day than neonates with other conditions. Infants who were converted from VV to VA required more transfusions per day (mean: 1.57) than did patients on VA (1.47) or VV (1.06).

CONCLUSIONS

Platelet transfusions among neonates on ECMO are dependent of their medical diagnosis; they average 1.3 transfusions per day and are higher on VA than VV ECMO.

Adrenocortical insufficiency in infants with congenital diaphragmatic hernia: a pilot study

BACKGROUND/PURPOSE

Prior reports have documented that premature infants do not have normal serum levels of cortisol. In contrast, full-term infants usually have adequate cortisol levels. The stress response in critically ill infants may be vital to their recovery. The purpose of this pilot study was to determine whether critically ill full-term infants with congenital diaphragmatic hernia (CDH) show a subnormal adrenal stress response.

METHODS

Random serum cortisol levels in infants with CDH (n = 10) were measured using fluorescent polarization immunoassay. In addition, serum cortisol levels were measured after exogenous adrenocorticotropic hormone stimulation (Cosyntropin stimulation test).

RESULTS

Six of the 10 infants studied died. Most (79%) of the cortisol levels were subnormal (<7 microgm/dL). Although no significant differences in mean cortisol levels from terminally ill infants compared with surviving infants were detected, survivors tended to have higher cortisol levels. Cosyntropin stimulation resulted in inappropriately low cortisol levels in 2 of the 4 fatally ill patients tested (<30 microgm/dL) and normal responses in the 2 survivors tested.

CONCLUSIONS

Infants born with CDH may have an inadequate adrenal stress response despite a life-threatening anomaly. A large-scale prospective study may be warranted to confirm this apparent association. Corticosteroid therapy may be beneficial in this population of patients.

Detrimental effects of standard medical therapy in congenital diaphragmatic hernia

OBJECTIVE

To evaluate the impact of a nonstandard ventilation strategy on survival in congenital diaphragmatic hernia (CDH).

BACKGROUND

Despite recent advances, including nitric oxide, CDH remains an unsolved problem with a mortality rate of 35% to 50%. Hyperventilation and alkalization remain common therapies.

METHODS

In 1992, the authors prospectively abandoned hyperventilation and alkalization. Patients are lightly sedated and ventilated with the lowest pressure providing adequate chest movement, and the rate is set to patient comfort. Nitric oxide and extracorporeal membrane oxygenation (ECMO) are reserved for life-threatening instability. Surgical repair is delayed 1 to 5 days. Sixty consecutive patients are compared with 29 previous patients treated with hyperventilation and alkalization, 13 before and 16 after the availability of ECMO.

RESULTS

Overall, 47 of 60 patients (78%) in study era 3 survived compared with 2 of 13 (15%) in the hyperventilation era and 7 of 16 (44%) in the hyperventilation/ECMO era (p < 0.0001). The disease severity and the incidence of associated anomalies did not differ between groups. To compare management strategies, patients who had treatment withheld because of lethal associated conditions were then removed from analysis. Peak inspiratory pressure and arterial pH were lower (p < 0.0001) and Paco2 was higher (p < 0.05) in era 3 than in the previous eras. The rate of pneumothorax (1.9%) decreased (p < 0.0001). In era 3, survival was 47 of 53 (89%) treated patients, and 23 of 25 inborn patients with isolated CDH survived (92%).

CONCLUSIONS

Nonstandard ventilatory support of patients with CDH has led to significantly improved survival rates. This study sets a survival benchmark and strongly suggests the negative effects of hyperventilation and alkalization.

Retinol status of newborn infants with congenital diaphragmatic hernia

The etiology of congenital diaphragmatic hernia (CDH) is not yet known. Studies in the literature from 1941 have reported that nutritional deficiency of vitamin A during pregnancy could lead to CDH, associated or not with other malformations in young rats. More recently, possible correlations between expression patterns of cellular retinoid-binding protein and retinoic-acid receptors and morphologic effects of vitamin A deficiency have been suggested. The purpose of this study was to verify in human newborns the possible link between vitamin A deficiency and CDH previously observed in experimental animals. Blood samples were obtained during the first hours after birth from 11 term CDH newborns and 11 healthy controls matched for gestational age, and also from 7 mothers in each group, for a total of 7 newborn-mother pairs of matched CDH-controls. Plasma retinol was measured by high-performance liquid chromatography and retinol-binding protein (RBP) by nephelometry. In the 11 matched CDH-control newborns, plasma retinol and RBP levels in CDH newborns were 50% less than control values (P< 0.0002 and <0.006, respectively); in contrast, retinol levels in CDH mothers were significantly higher than those of control mothers (P < 0.005). The observation that the plasma concentrations of retinol and RBP are low in infants with CDH relative to controls may be clinically very relevant and may help to elucidate the mechanism of development of this congenital anomaly.

Is delayed surgery really better for congenital diaphragmatic hernia?: a prospective randomized clinical trial

Delayed surgery has become widely accepted in the management of congenital diaphragmatic hernia after comparing outcomes only with historical retrospective controls. It was the aim of this study to compare early and delayed hernia repair in a randomized prospective clinical trial. Fifty-four infants were randomized to receive either early repair (within 4 hours of admission) or delayed repair (more than 24 hours after birth). The survival rate was higher for the delayed group (57% v 46%), but the difference was not significant (difference: -11; 95% confidence limits: -37.5, 15.5). There were no significant differences between the two groups with respect to length of hospital stay, ventilator dependency, or survival time. Recorded preoperative risk factors were similar for the two groups. Eight infants in the delayed repair group died without having undergone surgery. The optimum time for surgery still needs clarification.

Timing of repair of congenital diaphragmatic hernia requiring extracorporeal membrane oxygenation support

Treatment of congenital diaphragmatic hernia (CDH) has undergone a revolutionary change in philosophy, from previous urgent repair to the present practice of stabilization and delayed repair. However, when extracorporeal membrane oxygenation (ECMO) is required, many people believe that the risk of postoperative pulmonary hypertension (PPHN) mandates hernia repair while on ECMO. This report details the experience in two ECMO centers with stabilization, ECMO if required, and CDH repair post-ECMO. All CDH patients symptomatic in the first hour of life with a gestational age of at least 34 weeks during the period were reviewed retrospectively. Standard criteria were used to select patients for ECMO. High-frequency jet or oscillating ventilators and nitric oxide were not routinely available throughout the study period, but were used in some of the more recent patients. A total of 60 patients presented to the two centers; 24 cases were stabilized with conventional management, repair of the CDH was done elective, and survival was 100%. Eight patients were referred after having repair elsewhere; six survived (75%). The two deaths were attributable to associated lethal lesions--complex cyanotic heart disease and alveolar capillary dysplasia. Eight patients who required ECMO were managed with the intention of repairing the defect on ECMO. Four survived (50%). Two patients died before repair. Twenty patients were managed with ECMO, with the intention of repairing the defect after decannulation. Overall survival was 13 (65%), deaths were caused by pre-ECMO hypoxia, pulmonary insufficiency, and associated cardiac disease. No patient had recurrent pulmonary hypertension after late repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Nucleated erythrocyte count in newborn infants with left-sided congenital diaphragmatic hernia: relationship with the need for extracorporeal membrane oxygenation and survival

Inadequate cardiac output in fetuses with left-sided congenital diaphragmatic hernia may cause chronic hypoxia and increased erythropoiesis. Postnatal nucleated erythrocyte counts were measured in 28 newborn infants with left-sided congenital diaphragmatic hernia who were eligible for extracorporeal membrane oxygenation (ECMO). Nucleated erythrocyte counts were lowest in infants who survived without ECMO, intermediate in survivors requiring ECMO, and highest in infants who died despite ECMO.

Plasma endothelin levels in congenital diaphragmatic hernia

Persistent pulmonary hypertension (PPH) together with pulmonary hypoplasia accounts for high mortality among patients with congenital diaphragmatic hernia (CDH). Endothelin (ET) is a recently described endothelium-derived vasoconstrictor peptide with a potent and sustained effect. The authors examined plasma ET levels in eight patients with CDH who had respiratory distress at birth and in 15 age-matched controls. The plasma ET levels were measured using a highly sensitive and specific enzyme immunometeric assay (EIA) preoperatively, intraoperatively, and 24 and 48 hours postoperatively. The mean preoperative plasma ET level (53.9 +/- 21.1 pg/mL) of the patients was significantly (P < .01) higher than that of controls (5.9 +/- 4.5 pg/mL). Two patients who died before operation had plasma ET levels of 60 pg/mL and 82 pg/mL, respectively. Three patients who had PPH postoperatively continued to have high ET levels, and at 48 hours, the mean plasma ET level in these patients was 33 pg/mL. In contrast, in the three patients who survived after repair of CDH, the mean plasma ET level at 48 hours was 1.3 pg/mL. The authors further examined the lungs of two patients who died before operation for the expression of ET, using immunocytochemistry. Pulmonary endothelial cells had strong ET staining compared with control tissues. These findings suggest that ET may be a pathophysiological mediator of pulmonary hypertension in patients with CDH.

[Prognostic factors in congenital diaphragmatic hernia. Can they modify our therapeutic approach?]

Mortality rate from congenital diaphragmatic hernia (CDH) is still high despite current therapeutic advances. For some time now we have been looking for prognostic parameters which be enable us to determine, in the prenatal and postnatal period, the patients who will die from their pulmonary hypoplasia in spite of treatment and those who will survive. The authors review 94 newborns with CDH diagnosed during the first 24 hours of life. The following prognostic parameters were studied: preoperative arterial gases, position of stomach, right or left sided hernia, liver in thorax and presence of postoperative pneumothorax. All these factors were related to mortality. The arterial gases were the most sensitive factor. Eighty per cent of patients with poor gasometric prognosis died. Thoracic stomach is also a poor prognostic parameter with a 76.7% mortality rate, however we think this does not justify prenatal surgical measures. The remaining parameters were not significant with regard to mortality.

[Results of extracorporeal membrane oxygenation (ECMO) and perspectives for the asphyctic newborn infant]

Extracorporeal life support with membrane oxygenation (ECMO) has been successfully introduced into the management of asphyctic neonates. Two case studies are given to show the importance of this method in antenatal obstetric management.

Relation between arterial hypoxemia and plasma eicosanoids in neonates with congenital diaphragmatic hernia

Pulmonary hypertension is a major source of morbidity and mortality in infants born with congenital diaphragmatic hernia (CDH). Increased pulmonary vascular resistance leads to right-to-left shunting, which is evident as decreases in the PaO2 measured in postductal arterial blood. Thromboxane A2 (TXA2), a vasoconstrictor, and prostacyclin (prostaglandin I2, PGI2), a vasodilator, have been studied as possible mediators of pulmonary hypertension in certain conditions of the newborn, including congenital diaphragmatic hernia (CDH). The goal of our study was to determine the association of TXA2 and PGI2 levels with hypoxemia in infants born with CDH. Eleven newborn infants with severe respiratory insufficiency (birth weight 2.0-4.1 kg; gestational age 32-42 weeks) were studied 0-5 days after surgical repair of CDH. Umbilical artery samples were collected for arterial blood gas determinations and radioimmunoassay of thromboxane B2 (TXB2) and 6-keto prostaglandin F1 alpha (6-keto-PGF1 alpha), stable metabolites of TXA2 and PGI2, respectively. Postductal arterial hypoxemia (reflected by a low a-A ratio, the ratio of oxygen tension in arterial blood to that in the alveolus) was associated with increases in TXB2 (r = -0.71, P = 0.004) and 6-keto-PGF1 (r = -0.65, P = 0.017). The a-A ratio also correlated inversely with TXB2/6-keto-PGF1 alpha (r = -0.50, P = 0.01), suggesting an increased influence of the vasoconstrictor TXA2.(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital diaphragmatic hernia: predictors of severity in the ECMO era

Infants with congenital diaphragmatic hernia (CDH) demonstrate a wide range of anatomic and physiologic abnormalities, making it difficult to compare the efficacy of new forms of therapy such as extracorporeal membrane oxygenation (ECMO) among institutions. This study was undertaken to determine whether any predictors of severity could be identified in the ECMO era. The charts of all patients with CDH treated at this institution since 1984, when ECMO became available. (n = 110), were reviewed. Infants were considered high risk and included in this study if they presented with respiratory distress within the first 6 hours of life (n = 94). In order to focus on predictors of pulmonary insufficiency, patients who died of nonpulmonary causes or had other significant congenital anomalies were excluded from this review, leaving 59 patients for analysis. All the infants during this period had intensive pharmacological and ventilatory support. When needed, ECMO was offered postoperatively from 1984 to 1987, and preoperatively from 1987 to the present. Forty-five of 59 had a best postductal PO2 (BPDPO2) greater than 100 mm Hg, and 41 of these responders survived (91%). Fourteen patients had a BPDPO2 less than 100 mm Hg and only one survived (7%) (P = .0001). Mean BPDPO2 between survivors with or without ECMO, and nonsurvivors were also significantly different (P = .001). To incorporate ventilatory information, an oxygenation/ventilation index was devised: [OVI = PO2/(mean airway pressure x respiratory rate) x 100]. Differences in OVI between these three groups were also significant. When analyzing the data by the method proposed by Bohn (PCO2 v VI), no correlation between ventilatory parameters and outcome was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital diaphragmatic hernia: impact of prostanoids in the perioperative period

A prospective study of 10 neonates with congenital diaphragmatic hernia and five controls to determine the importance of prostanoid concentrations perioperatively and the relation with persistent pulmonary hypertension (PPH) is reported. In neonates with congenital diaphragmatic hernia postoperative concentrations of the vasoconstrictor thromboxane B2 rose significantly and were higher during episodes of PPH; this rise may provoke PPH and subsequent right to left shunting.

Ventilation parameters and arterial blood gases as a prediction of hypoplasia in congenital diaphragmatic hernia

Attempts to predict the degree of pulmonary hypoplasia associated with congenital diaphragmatic hernia have been made by evaluating the ventilation parameters and the arterial blood gasses of these patients. A CO2 index as a predictor of outcome, which correlates the PaCO2 with the ventilation index, was recently proposed. However, in this study the postductal PaO2 was a better predictor of survival. And the so-called "honeymoon period" was a better indicator of the efficacy of extracorporeal membrane oxygenation (ECMO) than the CO2 index. Nineteen patients were evaluated; 11 were treated with ECMO, and eight were not considered suitable for ECMO.