Positive-pressure ventilation at moderately high frequency in newborn infants with respiratory distress syndrome (IRDS)

In 24 seriously ill newborn infants with respiratory distress syndrome (IRDS) and ensuing respiratory failure, high-frequency positive-pressure ventilation was administered. The mean gestational age of the infants was 32 +/- 3 weeks. In the infant ventilator employed, the compressible volume had been reduced in order to give higher flow rates but lower intratracheal pressures. The ventilation frequency was kept constant at 60-66 per min and the insufflation period at 32-35% of the ventilatory cycle. A positive end-expiratory pressure (PEEP) of 0.2-0.6 kPa was used. Arterial PCO2 was maintained at 4.0-5.3 kPa and PO2 at 8.5-10.5 kPa by adjusting the gas flow through the patient circuit, the peak tubing pressure, the PEEP and the oxygen concentration in inspired gas. High-frequency positive-pressure ventilation improved oxygenation and gave adequate alveolar ventilation in all infants, in most cases at a low peak pressure. Only one infant developed pneumothorax during intermittent positive pressure ventilation, and in no infant did bronchopulmonary dysplasia or retrolental fibroplasia occur. One infant died from intracranial hemorrhage during the ventilation period, giving a survival rate of 96%.     

Measurement of pulmonary status and surfactant protein levels during dexamethasone treatment of neonatal respiratory distress syndrome.

BACKGROUND: Early postnatal use of dexamethasone in infants with respiratory distress syndrome (RDS) has been shown effectively to improve pulmonary status and to allow early weaning off mechanical ventilation. However, the mechanisms to explain the beneficial effects of dexamethasone in ventilatory dependent preterm infants remain unclear. METHODS: A double blind, placebo controlled study was performed to determine the change in pulmonary ventilation of premature infants with RDS as a result of dexamethasone treatment, and to evaluate the effect of dexamethasone on the levels of surfactant-associated proteins A (SP-A) and D (SP-D) in the tracheal fluid from 34 premature infants with RDS and 29 control subjects. RESULTS: Dexamethasone treatment decreased fractional inspired oxygen concentration (FIO2), arterial carbon dioxide tension (PCO2), mean airway pressure (MAP), and facilitated successful weaning from mechanical ventilation. SP-A concentrations in the tracheal aspirates were increased at days 7 and 14, and SP-D concentrations were increased during the period from days 3 to 14 in the dexamethasone treated group compared with the control group. However, albumin levels in the tracheal aspirate samples were decreased after dexamethasone treatment over the period from days 3 to 14. There was an inverse correlation between PCO2 values and SP-A concentrations. CONCLUSIONS: These results suggest that early use of dexamethasone can improve pulmonary status and also increase SP-A and SP-D levels in the tracheal fluid in premature infants with RDS.     

Efficacy of a pneumonia prevention protocol in the reduction of ventilator-associated pneumonia in trauma patients

BACKGROUND: We hypothesized that implementing evidence-based ventilator-associated pneumonia (VAP) prevention (VAPP) strategies would decrease the incidence of VAP, and that VAP affects patient outcomes. METHODS: A prospective study was performed with 331 consecutive ventilated trauma patients in a level one university teaching hospital. The VAPP protocol was modified to include elevation of the head of the bed more than 30 degrees , twice-daily chlorhexidine oral cleansing, a once-daily respiratory therapy-driven weaning attempt, and conversion from a nasogastric to an orogastric tube whenever possible. Ventilator days were compared with occurrences of nosocomial pneumonia, as defined by the U.S. Centers for Disease Control National Nosocomial Infection Surveillance criteria. Patients with and without VAP were compared to discern the effect VAP has on outcome. RESULTS: In 2003, there were 1,600 days of ventilator support with 11 occurrences of VAP (6.9/1,000 ventilator days). In 2004, there were two occurrences of VAP in 703 days of ventilation (2.8/1,000 ventilator days). In the analysis of outcomes of the patients with and without VAP, there was a statistically significant difference in total hospital days (38.7 +/- 26.2 vs. 13.3 +/- 15.5), ICU days (27.8 +/- 12.6 vs. 7.5 +/- 9.7), ventilator days (21.1 +/- 9.8 vs. 6.0 +/- 10.3), Functional Independence Measures (7.25 +/- 2.3 vs. 10.8 +/- 1.8), and hospital charges ($371,416.70 +/- $227,774.31 vs. $138,317.39 +/- $208,346.64)(p < 0.05 for all). The mortality rate did not decrease significantly (20% vs. 7.5%; p = NS). The difference in the mean Injury Severity Score in the two groups was not significant (21.9 +/- 9.6 vs. 16.7 +/- 11.4 points) and thus could not account for the differences in outcomes. CONCLUSION: These data suggest that a VAPP protocol may reduce VAP in trauma patients. Ventilator-associated pneumonia may result in more hospital, ICU, and ventilator days and higher patient charges.     

Management of infants with large, unrepaired ventricular septal defects and respiratory infection requiring mechanical ventilation

OBJECTIVES: We sought to describe the hospital management and early outcome of critically ill infants presenting with large ventricular septal defects and pneumonia requiring mechanical ventilation at a referral center in a developing country. Infants with large ventricular septal defects who have pneumonia might present with respiratory failure requiring mechanical ventilation. In the developing world this presentation is relatively common, but few data exist describing patient management strategies. METHODS: Hospital data of consecutive infants admitted with large ventricular septal defects and pneumonia requiring mechanical ventilation were reviewed and analyzed. RESULTS: We identified 18 infants (mean age, 3.6 +/- 3.0 months). On admission, all the infants were significantly malnourished, and echocardiography showed bidirectional shunting (predominantly right-to-left shunting) in 6 infants. Thirteen (72%) patients improved with intensive medical management that included mechanical ventilation for 1 to 16 days (median, 6.5 days); unequivocal left-to-right shunting was subsequently documented by means of echocardiography in all 13 patients. Twelve patients underwent surgical repair, and 11 (91.6%) were discharged after median mechanical ventilation of 100 hours (range, 42-240 hours) and intensive care unit stay of 8 days (range, 4-15 days). Five of 6 unoperated patients died, 4 of them within a few hours of admission. One child with multiple ventricular septal defects was discharged and subsequently underwent pulmonary artery banding. CONCLUSION: Corrective cardiac surgery for selected critically ill infants with large ventricular septal defects, severe malnutrition, and pneumonia requiring mechanical ventilation is feasible and should be considered a viable management strategy.     

The role of high-frequency ventilation in post-traumatic respiratory insufficiency

Post-traumatic pulmonary insufficiency or the adult respiratory distress syndrome is not infrequently associated with multiple organ-system injury. Mortality presently approaches 50%. Mechanical ventilation (CMV) with continuous positive airway pressure (CPAP) remains the mainstay of therapy. High peak inspiration (PIP) and mean airway (PAW) pressure in association with the delivery of large, conventional mechanical breaths are major determinants of complications. The efficacy of HFV was evaluated in this patient population (45 patients, mean age, 32.7 +/- 14.4 years; range, 11-75). CMV was provided with a time-cycled ventilator delivering 12-15 cc/kg tidal volume and a mechanical rate adjusted to provide a PaCO2 38-42 torr for patients previously eucapneic. CPAP was titrated to achieve a preselected endpoint of an intrapulmonary shunt of less than equal to 15%. FIO2 was maintained at or below 0.45 whenever possible. The Trauma Index Score for the group was 8.8 +/- 2.4. CMV yielded a mechanical rate of 6.3 +/- 3.2 and a CPAP of 13.9 +/- 8.5 cm H2O. High-frequency ventilation was provided by either a solenoid-based jet ventilator (HFJV) or a pneumatic cartridge high-frequency pulse generator (HFPG). Measured and calculated hemodynamic and pulmonary variables were obtained prior to and 20 minutes after transition to HFV. Thirty-three patients received HFJV; 12 patients received HFPG. Data were evaluated with a paired t-test. All patients on HFJV demonstrated improved CO2 elimination with the same hemodynamic profiles. Those on HFPG demonstrated comparable gas exchange and hemodynamic profiles with lower CPAP/PIP. Where measured, PAW was significantly lower with HFPG when compared with CMV.     

Intermittent CPAP: A New Mode of Ventilation during General Anesthesia

Background: Airway pressure-release ventilation provides ventilation comparable to controlled mechanical ventilation (CMV), but with lower peak airway pressures and less deadspace ventilation. To obtain these advantages for patients administered general anesthesia, the authors (1) designed a mode similar to airway pressure-release ventilation, intermittent continuous positive airway pressure (CPAPI), and compared its efficiency with that of CMV; and (2) assessed the accuracy of end-tidal carbon dioxide tension (PET (CO)2) as a monitor of the partial pressure of carbon dioxide in arterial blood (PaCO2) during CPAPI compared with during CMV.

Methods: Twenty anesthetized, tracheally intubated patients received baseline CMV that produced a PETCO2 of approximately 35 mmHg and a pulse oximetry value > 90%. Patients were assigned to undergo alternating trials of CMV and CPAPI. During CPAPI, CPAP was applied to the airway, removed for 1 s, and reapplied at a rate equal to the ventilator rate during CMV. The difference between the carbon dioxide tension in arterial blood and end-tidal gas [P(a - ET)CO2] and the calculation of PaCO2/minute ventilation quantified the efficiency of ventilation. Data were summarized as mean +/- SD and compared using the Student's test.

Results: Peak airway pressure (13 +/- 2 vs. 23 +/- 5 cm H2 O; P < 0.001) and minute ventilation (3.5 +/- vs. 4.6 +/- 1.2 l/min; P < 0.0001) were lower during CPAPI than during CMV. The value for PaCO2/minute ventilation (11.1 +/- 2.9 vs. 7.9 +/- 2.6 mmHg [middle dot] 1-1 [middle dot] min-1; P < 0.0001) was greater during CPAPI. P(a - ET)CO2 was always greater during CMV (6.3 +/- 1.6 vs. 1.7 +/- 0.9 mmHg; P < 0.0001) and was never > 3.5 mmHg during CPAPI.     

Extracorporeal membrane oxygenation for neonatal respiratory failure. A report of 50 cases

From February 1985 through June 1987, 50 newborn infants in whom maximal ventilator therapy failed (80% predicted mortality) were treated with extracorporeal membrane oxygenation (ECMO) according to the following inclusion criteria: arterial oxygen tension less than 50 torr (alveolar-arterial oxygen gradient greater than 630 torr) for 2 hours or arterial oxygen tension less than 60 torr (alveolar-arterial oxygen gradient greater than 620 torr) for 8 hours. Criteria for exclusion from ECMO therapy included birth weight less than 2000 gm, gestational age less than 35 weeks, presence of intracranial hemorrhage, presence of other major congenital anomalies including cyanotic heart disease, and high levels of ventilatory support for more than 7 days. Mean birth weight was 3.28 +/- 0.56 kg, mean gestational age was 39.6 +/- 1.7 weeks, and mean age at the start of ECMO was 48.6 +/- 36.9 hours. Meconium aspiration, usually associated with persistent pulmonary hypertension, was the most common cause of pulmonary failure (62%). Mean pre-ECMO arterial oxygen tension during maximal ventilatory and pharmacologic support was 34.5 +/- 14.5 torr. Mean ventilatory support immediately before the institution of ECMO was as follows: peak inspiratory pressure 46.8 +/- 9.9 cm H2O, positive end-expiratory pressure 4.6 +/- 1.6 cm H2O, and intermittent mandatory ventilation rate 101.0 +/- 22.7 breaths/min with all patients receiving an inspired oxygen fraction of 1.0. Lung management to prevent pulmonary atelectasis during ECMO consisted of moderate levels of positive end-expiratory pressure (mean 10.3 +/- 2.6 cm H2O, range 8 to 14 in 94% of patients. Other mean ventilator parameters during ECMO were as follows: peak inspiratory pressure 22.8 +/- 1.6 cm H2O, intermittent mandatory ventilation rate 11.8 +/- 2.9, and inspired oxygen fraction 0.21. The overall long-term patient survival rate was 90%. Mean values for arterial blood gases and ventilator settings immediately after the discontinuation of ECMO were as follows: oxygen tension 78.4 +/- 22.1 torr, pH 7.39 +/- 0.10, carbon dioxide tension 37.4 +/- 10.7 torr, peak inspiratory pressure 25.2 +/- 3.9 cm H2O, positive end-expiratory pressure 5.6 +/- 1.2 cm H2O, and intermittent mandatory ventilation rate 41.3 +/- 12.6 with an inspired oxygen fraction of 0.42 +/- 0.17. Despite slightly higher levels of ventilator support (peak inspiratory pressure 46.8 versus 45.0 cm H2O, not significant) mean pre-ECMO oxygen tension was significantly lower than that reported from the National ECMO Registry (34.5 versus 42.0 torr, p less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)     

Lung transplantation in very young infants.

INTRODUCTION: Established successes with adult lung transplantation have laid the foundation for extension of this therapeutic modality to infants and children dying of end-stage pulmonary disease. The purpose of this report is to convey our experience with 19 infants undergoing lung transplantation before the age of 6 months. METHODS: Six patients with predominantly pulmonary vascular disease and 13 patients with primarily pulmonary parenchymal disease have undergone bilateral sequential lung transplantation at our institution since 1990. Mean age at transplant was 104 +/- 44 days, and mean weight was 4.9 +/- 1.6 kg. RESULTS: Although early mortality (32%, 6/19) was higher than that previously reported for older pediatric age groups, long-term survival was similar (44% at a maximum follow-up of 6 years). Although anastomotic complications and infections occurred at a rate approximating that seen in older pediatric age groups, episodes of acute rejection appear to occur with decreased frequency. Similarly, at a mean follow-up of 3 years, only 2 (15%) of 13 long-term survivors have evidence of bronchiolitis obliterans. The functional residual capacity, as measured on infant pulmonary function tests, has gradually increased as the children have grown, suggesting that lung growth is occurring. CONCLUSIONS: Bilateral lung transplantation is a viable alternative in infants dying of end-stage pulmonary disease. Efforts directed toward avoiding the complications that lead to early posttransplant mortality combined with the seemingly lower incidence of early and late rejection may provide long-term results better than those in other age groups.     

Prediction of successful primary closure of congenital abdominal wall defects using intraoperative measurements

To determine whether intragastric pressure (IGP) and central venous pressure (CVP) would reliably predict successful primary closure of congenital abdominal wall defects (omphalocele/gastroschisis) in newborn infants, we developed the following prospective intraoperative management protocol. Following a temporary trial of fascial closure, infants who had an IGP less than 20 mm Hg or an increase in CVP of less than 4 mm Hg were primarily closed. If IGP was greater than 20 mm Hg or if CVP increased by more than 4 mm Hg, the temporary closure of the abdomen was reopened and a prosthetic silo was placed. Ten infants who were less than 24 hours old and averaged 2.7 kg (range, 1.4 to 4.2 kg) and 37-weeks gestation (range, 32 to 41 weeks) were studied. Eight infants met criteria for primary closure. Their IGP averaged 14 +/- 4 mm Hg (+/- SD) (range, 8 to 19 mm Hg), and their increase in CVP averaged 1 +/- 2 mm Hg (range, -2 to 3 mm Hg). In the two infants who required staged repair, IGP averaged 25 +/- 1 mm Hg (+/- SD) (range, 24 to 25 mm Hg), and the increase in CVP averaged 7 +/- 1 mm Hg (range, 6 to 8 mm Hg). All patients were anesthetized with fentanyl (12.5 micrograms/kg) and paralyzed with metocurine (0.3 mg/kg) intraoperatively. There were no postoperative complications in either group of patients related to increased intraabdominal pressure, and all patients were extubated within 48 hours of the initial surgery. We conclude that the intraoperative measurement of changes in IGP and CVP can serve as a guide to the operative management of congenital abdominal wall defects and can reliably predict successful outcome following repair.     

Accuracy of end-tidal PCO2 measurements using a sidestream capnometer in infants and children ventilated with the Sechrist infant ventilator

To determine the accuracy of end-tidal PCO2 (PETCO2) measurements analyzed with a sidestream capnometer in infants and children whose lungs were ventilated with a Sechrist infant ventilator and an Ayre's t-piece, we compared PETCO2 measurements obtained from the proximal (PETCO2-p) and distal (PETCO2-d) ends of the tracheal tube to arterial PCO2 (PaCO2) in 37 healthy infants and children between 1.3 and 24.5 kg. Both PETCO2-p and PETCO2-d accurately approximated PaCO2, however, the mean (+/- SD) arterial to end-tidal PCO2 difference (delta(a-ET)PCO2) was significantly greater with proximal (1.27 +/- 1.54 mmHg) than with distal sampling (0.64 +/- 1.64 mmHg) (P less than 0.01). In the subgroup of patients who weighted less than 12 kg, the delta(a-ET)PCO2 using proximal gas sampling (1.94 +/- 1.29 mmHg) was also significantly greater than it was using distal sampling (0.74 +/- 1.31 mmHg) (P less than 0.001). We conclude that although statistically different, both proximal and distal estimates of PETCO2 provide acceptable estimates of PaCO2 in healthy infants and children who are ventilated with a Sechrist infant ventilator and an Ayre's t-piece system.     

Weaning from ventilator after cardiac operation using the Ciaglia percutaneous tracheostomy.

OBJECTIVE: To determine the predictors of weaning from mechanical ventilation after cardiac operation with the Ciaglia percutaneous dilatational tracheostomy (PDT) in our preliminary experience in the use of this technique. METHODS: We prospectively analysed 33 consecutive patients (mean age 70.9+/-12.7 years) who underwent PDT in our intensive care unit after cardiac operation. The investigation involved preoperative and postoperative clinical status, operative procedure, indication and timing for PDT. RESULTS: PDT was performed after a mean time of 7.7+/-5.0 consecutive days of translaryngeal intubation. Twenty-four (73%) patients were weaned from ventilator after a mean time of mechanical ventilation of 15.8+/-9.1 days. Time point of PDT was the only predictor of ventilator weaning (P=0.0029): there was significant association between PDT performed before the seventh consecutive day of translaryngeal intubation (early PDT) and successful weaning from ventilator (P=0.01; odds ratio=11.2, 95% confidence interval=1.2-104.3). Among the patients weaned from ventilator, those who underwent early PDT had significantly shorter times of mechanical ventilation, and intensive care unit and hospital stays than patients with later PDT (P=0.035, 0.011 and 0.0073, respectively). Nine (27%) patients died of their underlying disease while still being mechanically ventilated; another six (18%) spontaneously breathing but still incannulated patients died afterward. No major PDT-related complications were observed. Two minor peristomal bleedings and one self-resolving subcutaneous emphysema were recorded. CONCLUSIONS: Early PDT was a safe and effective method to wean from mechanical ventilation the cardiosurgical patients of this series.     

Respiratory paralysis to improve oxygenation and mortality in large newborn infants with respiratory distress

The nonsynchronous respiratory efforts of neonates with surgically correctable disorders may inhibit effective mechanical ventilation. The records of 25 infants treated with metocurine for muscular paralysis to improve mechanical ventilation were reviewed. All patients were greater than 35 (37.6 +/- 2.1) weeks gestation and 2.27 (2.98 +/- .47) kg. All required ventilatory support with an FiO2 of 100%. The mortality rate of this group of infants was 20% as compared with 73% (p < .001) in a similar group of 26 infants managed without paralysis. In 10 of the 25 infants treated with metocurine, pre- and 1 hr postparalysis paO2 values were available. The mean paO2 prior to paralysis was 62 (45--111) mm Hg and the mean post-paralysis paO2 was 144 (75--227) mm Hg, representing at 132% increase in paO2 (p < .001). The mean dosage for metocurine was 3.5 (1.45--6.79) mg/kg/day; however, those requiring paralysis for greater than 7 days showed a dramatically increasing requirement. These preliminary data suggest that respiratory paralysis reduces right-to-left shunting, improves paO2 and decreases mortality in large infants with severe respiratory distress requiring ventilatory support.     

Benefits and risks associated with the R100 high frequency oscillatory ventilator for patients with severe hypoxaemic respiratory failure

High frequency oscillatory ventilation has been shown to improve oxygenation of patients with severe respiratory failure. This prospective study examined the potential benefits and risks of the latest generation high frequency oscillatory ventilator (R100, Metran, Saitama, Japan), initiated when the target oxygenation could not be achieved by conventional mechanical ventilation in adult patients with severe hypoxaemic respiratory failure. Thirty-six patients with severe respiratory failure treated with the R100 high frequency oscillatory ventilator were considered. Pneumonia and exacerbation of interstitial pneumonia were the main causes of respiratory failure. The median time on conventional mechanical ventilation or airway pressure release ventilation prior to high frequency oscillatory ventilation was 9.3 hours (interquartile range 4.8 to 25). PaO2/FiO2 at 24 hours after initiation of high frequency oscillatory ventilation was significantly better than the PaO2/FiO2 at baseline (151.2 +/- 61.2 vs. 99.5 +/- 50.0, P = 0.0001). Refractory hypoxaemia within 24 hours was associated with a high risk of mortality (P = 0.0092) and 23 patients (64%), including 11 patients with exacerbation of interstitial pneumonia, died by 30 days. Of the 36 patients included in the study (including one who had developed pneumothorax before high frequency oscillatory ventilation), 12 (33%) developed barotrauma during the course of their intensive care unit stay. In the multivariate analysis, only exacerbation of interstitial pneumonia was a significant risk factor for barotrauma. In summary, the latest generation high frequency oscillatory ventilator could improve oxygenation in adult patients with life-threatening hypoxaemic respiratory failure but the incidence of barotrauma was substantial.     

Pulmonary vascular resistance after cardiopulmonary bypass in infants: effect on postoperative recovery

OBJECTIVE: We sought to define the contemporary clinical effect of increased pulmonary vascular resistance in infants after congenital heart operations with cardiopulmonary bypass. METHODS: Fifteen infants (median age, 0.31 years; median weight, 5.1 kg) underwent cardiac operations involving cardiopulmonary bypass (range, 49-147 minutes). Pulmonary vascular resistance was measured in the immediate postoperative period in the intensive care unit by means of the direct Fick principle, with respiratory mass spectrometry to measure oxygen consumption. The effect of ventilation with an inspired oxygen fraction of 0.65, with additional infusion of L -arginine, substance P, and inhaled nitric oxide, was assessed and subsequently correlated with the length of mechanical ventilation from the end of cardiopulmonary bypass to successful extubation. RESULTS: Overall, pulmonary vascular resistance at baseline (11.7 +/- 5.6 WU. m(2)) could be reduced to a minimum of 6.1 +/- 3.5 WU. m(2). The ventilatory time was 0.86 to 14.9 days (median, 1.75 days) and correlated directly with the lowest pulmonary vascular resistance value achieved during the pulmonary vascular resistance study (r (2) = 0.64, P <.01). The patient subgroup with mechanical ventilation of greater than 2 days had significantly higher pulmonary vascular resistance at all stages of the study protocol, and in this group there was a correlation of cardiopulmonary bypass time and ventilatory support time (r (2) = 0.48, P <.05). CONCLUSION: Increased pulmonary vascular resistance, either directly or as a surrogate of the systemic inflammatory response after cardiopulmonary bypass, continues to have a significant effect on postoperative recovery of infants after cardiac operations.     

Percutaneous dilatational tracheostomy

BACKGROUND: The aim of this study was to investigate the rate, timing, the incidence of complications of percutaneous dilatational tracheostomy (PDT) and its effects by on nosocomial pneumonia. METHODS: The study is a retrospective analysis of 104 patients (56 males, 48 females) > or = 18 years (54 +/- 19) who had undergone a PDT for respiratory failure during the five years 1998-2003. RESULTS: Among 238 patients requiring mechanical ventilation > or = 48 hours, 104 (43.7%) required PDT. PDT was performed after 4.3 +/- 2.3 days of ventilation and the disconnection from mechanical ventilation was 13.6 +/- 8.5 days. Lower airway tract infection was detected in 88 patients: 55 patients (62.5%) before PDT and in 33 patients (37.5%) after PDT. The nosocomial pneumonia was observed after 5.9 +/- 1.67 days of ventilation. CONCLUSIONS: Our results suggest that PDT was performed relatively early, with an acceptable complication rate and that our post-PDT nosocomial pneumonia incidence is low.     

Inguinal hernia repair in the perinatal period and early infancy: clinical considerations

Contemporary neonatal intensive care has resulted in survival of many seriously ill preterm and older infants that frequently present with symptomatic inguinal hernia. Controversy exists concerning timing and safety of early repair in prematures or other neonates, especially those hospitalized with concurrent illness. This study examines this topic by evaluating predisposing factors, presentation, and postoperative complications in 100 recent consecutive hernia repairs in previously hospitalized infants less than 2 months of age. There were 85 boys and 15 girls. Thirty percent were premature (less than 36 wks gestation). Forty-two infants were hospitalized for RDS with assisted ventilation in 16 infants, hydrocephalus and ventriculoperitoneal (VP) shunt in 7 infants, and congenital heart disease (CHD) in 19 infants. Clinical presentation was on the right side in 44 infants, bilateral in 42, and on the left side in 14. Incarceration occurred in 31 cases with nine babies having overt intestinal obstruction. The incidence of cryptorchidism was 12.9%. All (VP) shunt, CHD patients, and incarcerated cases were treated with preoperative antibiotics. Following discharge, 49 preterm or previously ill infants developed a symptomatic hernia at home and were readmitted. Nine full-term infants were treated as outpatients. Bilateral inguinal exploration was performed in 92 cases with second hernia or patent processus found in 81. Seven of eight with unilateral exploration had acute incarceration with obstruction at the time of the procedure. Three subsequently required a second hernia repair. Two infants with incarceration and cryptorchid testis or ovarian slider had gonadal infarction. There were eight postoperative complications.(ABSTRACT TRUNCATED AT 250 WORDS)     

"Acquired" lobar emphysema: a complication of respiratory distress in premature infants

Ten premature infants with respiratory distress developed a type of pulmonary lobar emphysema that is clinically and histologically distinct from interstitial or congenital lobar emphysema. In eight patients emphysema was noted in the right lower lobe, while in two the left upper lobe was affected. Five infants exhibited nonresolution of the emphysema and an inability to be weaned from ventilator support. Lung scans in these five infants showed absent or markedly decreased perfusion of the involved lobe. Lobectomy was necessary. Postoperatively, their respiratory status improved and they were successfully weaned from the ventilator. Five premature infants with identical radiographic emphysematous changes had normal lung scans. These infants did not require lobectomy and were also successfully weaned from the ventilator. Radiographic changes of lobar emphysema in these five infants completely resolved. Pathologic changes in the excised lobes were characteristic of bronchopulmonary dysplasia and obstructive intraalveolar emphysema. The long-term effects of positive pressure ventilation, oxygen, and suctioning techniques directed toward the right lower lobe may play an important role in the etiology of "acquired" lobar emphysema.     

The effect of extracorporeal membrane oxygenation on the survival of neonates with high-risk congenital diaphragmatic hernia: 45 cases from a single institution

At The Children's Hospital, Boston (TCH), in the 3 years before extracorporeal membrane oxygenation (ECMO) was available, infants with high-risk congenital diaphragmatic hernia (CDH) had a 47% survival rate. In February 1984, ECMO was introduced and offered to all high-risk CDH infants with a 100% predicted mortality. Since February 1984, 45 infants with high-risk CDH presented to TCH. Twenty-six (58%) were supported with ECMO; 19 (42%) never met the criteria for 100% predicted mortality and were supported with conventional mechanical ventilation (CMV). Overall survival was 49%. Nine (35%) of the 26 ECMO patients survived. Thirteen (68%) of the 19 CMV patients survived. Although there was no change in survival, there was a change in the cause of death. Deaths in the ECMO group were either early (n = 8, secondary to a complication of ECMO or lack of pulmonary improvement) or late (n = 9). The late deaths were infants who were successfully weaned from ECMO, never weaned from CMV, and who died secondary to complications of chronic lung disease.     

Treatment of pulmonary manifestations of gastroesophageal reflux in children two years of age or less

Apnea and worsening bronchopulmonary dysplasia as well as recurrent aspiration pneumonia have been found to be consequences of gastroesophageal reflux in infants and young children. Antireflux procedures are effective in preventing gastroesophageal reflux; however, the effect of this operation on the course of these respiratory problems in very young patients is not known. We reviewed the results in 51 patients 2 years of age or less who underwent an antireflux fundoplication for pulmonary problems attributable to severe gastroesophageal reflux unresponsive to medical treatment. Twenty-eight patients had recurrent episodes of aspiration pneumonia, 14 had nonimproving or worsening bronchopulmonary dysplasia, and 9 had unexplained apneic episodes. Seventy-three percent of these patients had coexisting congenital anomalies or acquired problems. No operative deaths and no major surgical complications occurred. There were eight late deaths occurring between 1 and 25 months postoperatively: three were due to associated congenital anomalies or acquired problems, three to sepsis, and two to sudden infant death syndrome. Of the 43 surviving children, 91 percent with preoperative recurrent aspiration pneumonia had no additional episodes after Nissen procedure. Eighty-eight percent of the infants with unexplained apneic episodes showed marked benefit and 83 percent of those with bronchopulmonary dysplasia had clinical improvement. There were no late problems attributed to the operation even when it was performed in preterm infants. Therefore, we recommend fundoplication for patients 2 years of age or less who have a persistent pulmonary problem attributed to gastroesophageal reflux that does not respond to medical therapy.     

Pulmonary gas exchange effects of nitroglycerin in canine edematous lungs

The authors determined the effects of nitroglycerin on pulmonary edema induced by oleic acid injury. Measurements of venous admixture (QVA/Qt) and shunt (Qs/Qt) using both oxygen and inert-gas-elimination methods were done before, during, and after nitroglycerin infusion, first during air ventilation and then during ventilation with 100 per cent oxygen. Nitroglycerin reduced mean blood pressure (MAP) approximately 30 per cent (P less 0.01) during both air and oxygen ventilation. During air ventilation, nitroglycerin caused PVR to decrease by 29 per cent (P less than 0.01) but caused no change in PVR during oxygen ventilation. Pa02 decreased from 64 +/- 8 torr (mean +/- SD) to 55 +/- 9 torr (P less than 0.01) with nitroglycerin infusion during air ventilation. The decrease in Pa02 was primarily due to an increase in QVA/Qt which increased from 28 +/- 12 per cent to 36 +/- 14 per cent (oxygen method) (P less than 0.05). Similarly, the inert gas QVA/Qt increased from 31 +/- 10 to 37 +/- 14 per cent (P less than 0.05). During oxygen ventilation, the effect of nitroglycerin on gas exchange was similar in direction but less in magnitude. These results provide evidence that nitroglycerin may cause significance impairment of pulmonary gas exchange when abnormal lung function is present and FI02 is low. The mechanism is most likely due to inhibition of hypoxic pulmonary vasoconstriction.