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M Keszler

Publications and source records attributed to M Keszler.

28 records · Page 2Linked to original sources
PubMed1991

Multicenter controlled trial comparing high-frequency jet ventilation and conventional mechanical ventilation in newborn infants with pulmonary interstitial emphysema.

One hundred forty-four newborn infants with pulmonary interstitial emphysema were stratified by weight and severity of illness, and randomly assigned to receive treatment with high-frequency jet ventilation (HFJV) or rapid-rate conventional mechanical ventilation (CV) with short inspiratory time. If criteria for treatment failure were met, crossover to the alternate ventilatory mode was permitted. Overall, 45 (61%) of 74 infants met treatment success criteria with HFJV compared with 26 (37%) of 70 treated with CV (p less than 0.01). Eighty-four percent of patients who crossed over from CV to HFJV initially responded to the new treatment, and 45% ultimately met success criteria on HFJV. In contrast, only 9% of those who crossed over from HFJV to CV responded well to CV (p less than 0.01), and the same 9% ultimately met success criteria (p less than 0.05). Therapy with HFJV resulted in improved ventilation at lower peak and mean airway pressures, as well as more rapid radiographic improvement of pulmonary interstitial emphysema, in comparison with rapid-rate CV. Survival by original assignment was identical. When survival resulting from rescue by the alternate therapy in crossover patients was excluded, the survival rate was 64.9% for HFJV, compared with 47.1% for CV (p less than 0.05). The incidence of chronic lung disease, intraventricular hemorrhage, patent ductus arteriosus, airway obstruction, and new air leak was similar in both groups. We conclude that HFJV, as used in this study, is safe and is more effective than rapid-rate CV in the treatment of newborn infants with pulmonary interstitial emphysema.

Bronchopulmonary Dysplasia↗
PubMed1989

Pulmonary management during extracorporeal membrane oxygenation.

Traditional lung management during extracorporeal membrane oxygenation (ECMO) calls for low inspiratory and expiratory pressures with low ventilator rate to achieve lung rest. However, rapid weaning of pressures to severely injured lungs commonly leads to marked increase in pulmonary opacification as seen on chest x-ray and loss of volume. We postulated that a sufficiently high level of PEEP could prevent this deterioration. Forty-six newborns, who required ECMO therapy for refractory respiratory failure, were maintained on 8 to 14 cm H2O PEEP. The peak pressure was 20 to 24 cm H2O, rate 10 to 15 breath/min, and FIO2 0.21. Forty-one (89%) of 46 patients survived to discharge. The duration of ECMO was significantly decreased compared to the national average (82.4 +/- 43 vs. 117.5 +/- 59 h). The lungs of most patients remained adequately expanded and free of severe pulmonary opacification. Eleven of 40 patients did show significant worsening of chest x-ray compared to baseline, but only one of 18 who were on PEEP of greater than or equal to 12 cm H2O showed such deterioration. No unexpected complications were encountered. These data suggest that the use of high PEEP during ECMO safely prevents deterioration of lung function and promotes more rapid lung recovery. PEEP levels of 12 to 14 cm H2O appear to be most effective.

Extracorporeal Membrane Oxygenation↗
PubMed1989

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)

Extracorporeal Membrane Oxygenation↗
PubMed1988

Lung pathology after high frequency jet ventilation combined with low rate intermittent mandatory ventilation in a canine model of meconium aspiration.

The microscopic appearance of lungs subjected to six hours of conventional ventilation (CV), standard high frequency jet ventilation (HFJV), and HFJV combined with low rate intermittent mandatory ventilation (CHFJV) was studied in 22 mongrel puppies. A lung injury model was created by insufflating 4 ml/kg of a 20% mixture of meconium into the trachea. The animals were initially ventilated at the same mean airway pressure (Paw). Subsequently, if PCO2 fell below 20 torr, peak and mean airway pressures were reduced. A scoring system was devised which assigned 0-3 points for each of eight lung injury parameters, and a total lung injury score (TLIS) was calculated. CHFJV resulted in significantly less bronchopneumonia and edema, when compared to CV. A consistent, though not significant, trend toward lesser injury scores in CHFJV animals was noted for several other parameters. Six of eight lungs exposed to CV had TLIS greater than 5 compared to only 1 of 9 ventilated by CHFJV. (P = 0.02). It is concluded that CHFJV may have a protective effect on the lung, perhaps because effective gas exchange is achieved with a lower pressure amplitude and at lower Paw.

Animals↗
PubMed1986

Combined high-frequency jet ventilation in a meconium aspiration model.

To evaluate the effectiveness of high-frequency jet ventilation (HFJV) in the treatment of meconium aspiration, 28 puppies were assigned randomly to one of three ventilator techniques. After aspiration of 4 ml/kg of 20% meconium and baseline measurements on conventional ventilation (CV), the animals were ventilated for 6 h with either CV, HFJV, or HFJV combined with slow conventional ventilation (combined HFJV). Arterial and mixed venous blood gases, systemic and pulmonary arterial pressures, pulmonary capillary wedge pressure, and cardiac output were measured. Combined HFJV proved superior to the other two techniques, resulting in significantly better oxygenation and ventilation at a lower mean airway pressure (Paw). Oxygenation with standard HFJV was comparable to CV, producing Paw and PCO2 values intermediate between those of CV and combined HFJV. There were no significant intergroup differences in cardiac output or the incidence of pneumothorax. Improved gas exchange was attributed to alveolar recruitment and prevention of atelectasis. Alteration of the distribution and/or clearance of meconium may also be important.

Animals↗
PubMed1983

Pseudohypoaldosteronism.

Shortly after birth, a 1,860-g premature male newborn with respiratory distress syndrome had brisk diuresis, rapid weight loss, and severe hyponatremia despite aggressive Na+ and fluid replacement. The serum cortisol level was normal, and the 17-OH progesterone concentration was low. He did not show any response to treatment with dexamethasone and desoxycorticosterone acetate. Results of renal function studies were within the normal range for his gestational age. The serum aldosterone level and plasma renin activity were grossly elevated, confirming the diagnosis of pseudohypoaldosteronism. This uniquely early and dramatic presentation was attributed to immaturity of the proximal renal tubule at 32 weeks' gestation. The subsequent improvement paralleled the rapid maturation of the kidney after birth.

Aldosterone↗
PubMed1982

Effects of conventional and high frequency jet ventilation on lung parenchyma.

Despite the increasing acceptance of high frequency jet ventilation (HFJV), very little work has been done to determine if lung damage results from its use. We performed an experimental study to compare the effects of conventional ventilation with those of HFJV on the lung parenchyma of anesthetized dogs. Thirteen animals were studied for periods ranging from 2-24 h. Using a double-lumen Carlen's endotracheal tube, each animals's lungs were ventilated simultaneously but independently, one with conventional ventilation, the other with HFJV. No gross or microscopic evidence of atelectasis or barotrauma was noted in either group. Less hyperaeration was seen in the majority of jet ventilated lungs compared to the conventionally ventilated. In no case did the jet ventilated side show more damage than the control. We concluded that it is possible to use HFJV for 24 h without apparent parenchymal lung damage. Reduced hyperaeration is identified as a possible advantage of HFJV over conventional methods.

Animals↗
PubMedDate not supplied

Oxygen delivery with a single cannula tidal flow venovenous system for extracorporeal membrane oxygenation.

Venovenous tidal flow perfusion for extracorporeal membrane oxygenation via a single lumen cannula in the right atrium avoids the sacrifice of a carotid artery inherent in venoarterial systems, and eliminates the problems of two cannula venovenous perfusion. Oxygen delivery and hemodynamic effects of a single cannula, single lumen system with tidal flows directed by alternating tubing occluders were studied in six newborn lambs to define optimal system performance and possible adverse hemodynamic effects. The ratio of drainage to infusion time was fixed at 2:1 to avoid excessive reinfusion pressures. Total length of the in/out cycle was varied from 2-6 sec, resulting in a cycling frequency of 30 to 10 cycles/min and a tidal volume of 17-50 ml. Systemic arterial, mixed venous, and pre and post oxygenator partial pressure of oxygen and oxygen saturation were measured. Recirculation, oxygen delivery, and effective bypass flow (total flow--recirculated flow) were calculated. With slower cycling frequency, recirculation progressively fell, and effective flow and oxygen delivery increased (p < 0.001 for each parameter across the cycle length). In these animals, oxygen delivery was limited by low oxygen carrying capacity (mean hemoglobin, 8.1 g/dl). The authors concluded that with longer cycles, the system minimizes recirculation without apparent adverse hemodynamic consequences, achieving sufficient effective bypass flow to assure adequate oxygen delivery when hemoglobin levels are normal.

Animals↗
PubMedDate not supplied

Dose-dependent evaluation of the effects of nebulized furosemide on pulmonary function in ventilated preterm infants.

OBJECTIVE: We have previously shown that a single dose of nebulized furosemide improves tidal volume and pulmonary compliance for up to a 2-hour study period. This study is undertaken in order to find out (a) whether increasing the dose of nebulized furosemide from 1 to 2 mg/kg of body weight will further improve the pulmonary mechanics in premature infants with evolving chronic lung disease and (b) whether the effects of a single dose of nebulized furosemide last beyond 2 hours. STUDY DESIGN: The effect of nebulized furosemide on pulmonary mechanics was studied at a mean postnatal age of 24 days (range 14 to 50 days) in 13 premature infants, 24 to 28 weeks' gestational age, who had been dependent on mechanical ventilation since birth. Furosemide was administered by nebulization at doses of 1 and 2 mg/kg of body weight, in random order, on two separate days 24 hours apart. Pulmonary function studies were performed before and 2, 4, and 6 hours after the nebulization. Urine was collected for 6 hours immediately before and for 6 hours after the nebulization. RESULTS: Furosemide by nebulization at 1 and 2 mg/kg of body weight resulted in significant improvement in tidal volume and compliance. There was no difference in the magnitude of response between the two doses. Neither 1 nor 2 mg/kg of body weight of nebulized furosemide had any effect on airway resistance. The improvement was maximum for up to 4 hours and lasted for up to 6 hours after the nebulization and was not associated with diuresis or increased excretion of urinary electrolytes. CONCLUSION: A single dose of nebulized furosemide improves pulmonary function for up to 6 hours after its administration. Increasing the dose from 1 to 2 mg/kg of body weight results in no further improvement in the pulmonary function. The pulmonary effects of nebulized furosemide are independent of its diuretic action.

Aerosols↗