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M Keszler

Publications and source records attributed to M Keszler.

At least 19 recordsLinked to original sources
PubMed2001

Patient-ventilator interactions in new modes of patient-triggered ventilation.

Recently, synchronized modes of conventional mechanical ventilation became available for neonatal ventilatory support, but there has been little information regarding details of patient-ventilator interactions during pressure support, volume support, or any other volume-targeted modes of synchronized ventilation in newborn infants. Our objective was to obtain comparative data on patient-ventilator interactions and stability of delivered tidal volume (V(T)) for the different modes of synchronized mechanical ventilation in stable ventilated newborn infants. We examined the effects of pressure support ventilation (PSV) and volume guarantee (VG) modes of a prototype Dräger Babylog ventilator on peak and mean airway pressures (PIP and Paw), inspiratory time (t(in)), and V(T) in 23 ventilated newborn infants. Twelve infants were studied while on assist/control (AC) and 11 on synchronized intermittent mandatory ventilation (SIMV). Mean birth weight was 1,650 +/- 1,180 g, gestational age 31 +/- 6 weeks, and age at time of study was 19 +/- 26 days. Data for 400-600 breaths from each infant were downloaded directly from the ventilator pressure and volume-monitoring module, and analyzed using ANOVA for repeated measures. Mean values and breath-to-breath variability were compared for 20-min periods of AC or SIMV followed by PSV, PSV+VG, and back to baseline AC or SIMV. PSV and PSV+VG led to shorter t(in) and thus to lower Paw, compared to AC. Mean PIP was similar across all AC modes but more variable during VG, reflecting the servocontrol of PIP. V(T) did not differ between AC modes, but was significantly less variable with VG added. PSV and PSV+VG led to lower and less variable PIP and Paw, compared to SIMV, because t(in) was shorter and every breath was supported in PSV and PSV+VG. V(T) was similar in SIMV, PSV, and PSV+VG, but less variable with PSV+VG. Arterial blood gas tensions were similar across all ventilation modes. We conclude that the ventilator prototype functioned as intended. Breath-to-breath tidal volume variability was significantly reduced in VG modes, although not completely eliminated.

Blood Gas Analysis↗
PubMed2001

Neonatal high-frequency ventilation. Past, present, and future.

High-frequency ventilation has become established as an effective treatment modality in a variety of clinical situations. The laboratory and clinical investigations of these techniques have contributed tremendously to our understanding of the pathophysiology of respiratory failure and the important concept of maintaining adequate lung volume. Clinicians have come to appreciate better the factors involved in lung injury and the potential for damage to distant organs. The place of HFV in the therapeutic armamentarium will undoubtedly continue to evolve in the years to come. Of particular interest is the advent of advanced modes of fully synchronized and volume-targeted conventional mechanical ventilatory modes, along with the trend to use smaller tidal volumes and higher levels of PEEP with conventional ventilation. With these developments there seems to be a certain convergence of HFV and tidal ventilation that is the logical result of our improved understanding of respiratory pathophysiology. The available controlled trials of HFV versus tidal ventilation do not clearly differentiate whether improved outcomes are the result of HFV per se, or a reflection of the effects of optimizing lung volume, a benefit that may not be unique to HFV.

Animals↗
PubMed2000

Low-dose nitric oxide therapy for persistent pulmonary hypertension of the newborn. Clinical Inhaled Nitric Oxide Research Group.

BACKGROUND: Inhaled nitric oxide improves gas exchange in neonates, but the efficacy of low-dose inhaled nitric oxide in reducing the need for extracorporeal membrane oxygenation has not been established. METHODS: We conducted a clinical trial to determine whether low-dose inhaled nitric oxide would reduce the use of extracorporeal membrane oxygenation in neonates with pulmonary hypertension who were born after 34 weeks' gestation, were 4 days old or younger, required assisted ventilation, and had hypoxemic respiratory failure as defined by an oxygenation index of 25 or higher. The neonates who received nitric oxide were treated with 20 ppm for a maximum of 24 hours, followed by 5 ppm for no more than 96 hours. The primary end point of the study was the use of extracorporeal membrane oxygenation. RESULTS: Of 248 neonates enrolled, 126 were randomly assigned to the nitric oxide group and 122 to the control group. Extracorporeal membrane oxygenation was used in 78 neonates in the control group (64 percent) and in 48 neonates in the nitric oxide group (38 percent) (P=0.001). The 30-day mortality rate in the two groups was similar (8 percent in the control group and 7 percent in the nitric oxide group). Chronic lung disease developed less often in neonates treated with nitric oxide than in those in the control group (7 percent vs. 20 percent, P=0.02). The efficacy of nitric oxide was independent of the base-line oxygenation index and the primary pulmonary diagnosis. CONCLUSIONS: Inhaled nitric oxide reduces the extent to which extracorporeal membrane oxygenation is needed in neonates with hypoxemic respiratory failure and pulmonary hypertension.

Administration, Inhalation↗
PubMed1999

Dorsal penile nerve block vs topical placebo for circumcision in low-birth-weight neonates.

OBJECTIVE: To investigate the efficacy and safety of dorsal penile nerve block (DPNB) and eutectic mixture of lidocaine (EMLA) for palliation of pain associated with circumcision in low-birth-weight infants. DESIGN: Randomized, blinded, controlled trial. SETTING: Intensive care nursery (step down unit) at Georgetown University Medical Center, Washington, DC. PARTICIPANTS: Fifty neonates with weights of 1600 to 2500 g at the time of circumcision who were discharged from the hospital between May 1994 and June 1995 were randomly assigned to the DPNB, EMLA, or control group. Twenty-five infants who were otherwise eligible were excluded because of parental refusal of consent to participate. INTERVENTIONS: Infants in the DPNB and EMLA groups received anesthesia with subcutaneous injection of 1% lidocaine hydrochloride or topical EMLA, respectively. The control group received sham anesthesia with topical placebo (acid mantle cream). MAIN OUTCOME MEASURES: Changes in physiologic variables (heart rate, blood pressure, oxygen saturation, and respiratory rate) and behavioral score 20 minutes before, during, and 5 and 20 minutes after circumcision between DPNB and control groups. Surgical complications and adverse effects were also monitored. RESULTS: Fifty infants were enrolled in the study: 19 randomized to the DPNB group, 19 to the control group, and 12 to the EMLA group. Enrollment into the EMLA group was suspended early because of redness and blistering of the foreskin in 2 infants, and this entire group was excluded from further analysis. The clinical course was similar in all groups of infants. All circumcisions were performed without complication or technical difficulty. Statistically significant differences were noted in heart rate, respiratory rate, and behavioral score when comparing the DPNB group with controls during and after circumcision. CONCLUSION: Dorsal penile nerve block is safe and effective in controlling pain associated with circumcision in low-birth-weight infants.

Circumcision, Male↗
PubMed1998

Variations in transfusion practice in neonatal intensive care.

OBJECTIVE: To compare the transfusion practices between two neonatal intensive care units (NICUs) to assess the impact of local practice styles on the timing, number, and total volume of packed red cell transfusions in very low birth weight infants. To derive multivariate models to describe practice and to identify potential areas for improvement in the future. METHODOLOGY: We reviewed phlebotomy losses and transfusion rates between two NICUs (A and B) for 270 consecutive admissions of birth weight < 1500 g. We stratified for birth weight and for illness severity by the Score for Neonatal Acute Physiology (SNAP). Measures of short-term outcome were compared. We derived multivariate models to describe and compare the practices in the two NICUs. RESULTS: Patients in NICU A had smaller phlebotomy losses than those in NICU B. A lower percentage of the patients in NICU A (65% vs 87%) received transfusions, but they tended to receive a greater total volume per kg per patient (67 mL/kg vs 54.8 mL/kg). Transfusion timing differed between the NICUs; in NICU A only approximately one-half of their transfusions occurred in the first 2 weeks, whereas in NICU B almost 70% of the transfusions were given in this time period. Multivariate models showed that phlebotomy losses were significantly related to lower gestational age (GA) and higher SNAP. Hospitalization in NICU B resulted in 10.7 cc of additional losses relative to NICU A for a comparable GA and illness severity score. The volume of blood transfused per kilogram of body weight was a function of GA, SNAP, and hospital. Care practices in NICU A added an additional 19 cc of transfused volume in the first 14 days of life, and an additional 26 cc thereafter when adjusted for GA and SNAP. These differences in phlebotomy and transfusion were not associated with differences in the days of oxygen therapy or mechanical ventilation, the oxygen requirement at 28 days, the incidence of chronic lung disease, or the rate of growth by day 28. CONCLUSIONS: We identified significant differences in phlebotomy and transfusion practices between two NICUs. We found no differences in short-term outcome, suggesting that the additional use of blood in one of the NICUs was discretionary rather than necessary. Our multivariate models can be used to characterize and quantify transfusion and phlebotomy practices. By predicting which patients are likely to require multiple transfusions, clinicians can target patients for erythropoietin therapy and identify those patients for whom donor exposure can be reduced by a unit of blood for multiple use. The models may help in monitoring changes in practice as they occur.

Blood Transfusion↗
PubMed1997

Pulmonary function changes after nebulised and intravenous frusemide in ventilated premature infants.

AIMS: To compare the effects of a single dose of frusemide administered either intravenously or by nebulisation on pulmonary mechanics in premature infants with evolving chronic lung disease. METHODS: The effect of frusemide on pulmonary mechanics was studied at a median postnatal age of 23 (range 14-52) days in 19 premature infants at 24 to 30 weeks gestational age, who had been dependent on mechanical ventilation since birth. Frusemide (1 mg/kg/body weight) was administered, in random order, intravenously and by nebulisation, on two separate occasions 24 hours apart. Pulmonary function studies were performed before and at 30, 60, and 120 minutes after administration of frusemide. Urine was collected for six hours immediately before and for six hours after administration of frusemide. RESULTS: Nebulised frusemide increased the tidal volume 31 (SE 11.5)% and compliance 34 (SE 12)% after two hours, whereas no change in either was noted for up to two hours after intravenous frusemide administration. Neither intravenous nor nebulised frusemide had any effect on airway resistance. Six hour urine output increased from a mean (SE) of 3.3 (0.4) ml/kg/hour to 5.9 (0.8) ml/kg/hour following intravenous frusemide administration while nebulised frusemide had no effect on urine output. Urinary sodium, potassium, and chloride losses were also significantly higher after intravenous frusemide, whereas nebulised frusemide did not increase urinary electrolyte losses. CONCLUSION: Single dose nebulised frusemide improves pulmonary function in premature infants with evolving chronic lung disease without adverse effects on fluid and electrolyte balance.

Administration, Inhalation↗
PubMed1997

Multicenter controlled clinical trial of high-frequency jet ventilation in preterm infants with uncomplicated respiratory distress syndrome.

OBJECTIVE: To test the hypothesis that high-frequency jet ventilation (HFJV) will reduce the incidence and/or severity of bronchopulmonary dysplasia (BPD) and acute airleak in premature infants who, despite surfactant administration, require mechanical ventilation for respiratory distress syndrome. DESIGN: Multicenter, randomized, controlled clinical trial of HFJV and conventional ventilation (CV). Patients were to remain on assigned therapy for 14 days or until extubation, whichever came first. Crossover from CV to HFJV was allowed if bilateral pulmonary interstitial emphysema or bronchopleural fistula developed. Patients could cross over to the other ventilatory mode if failure criteria were met. The optimal lung volume strategy was mandated for HFJV by protocol to provide alveolar recruitment and optimize lung volume and ventilation/perfusion matching, while minimizing pressure amplitude and O2 requirements. CV management was not controlled by protocol. SETTING: Eight tertiary neonatal intensive care units. PATIENTS: Preterm infants with birth weights between 700 and 1500 g and gestational age <36 weeks who required mechanical ventilation with FIO2 >0.30 at 2 to 12 hours after surfactant administration, received surfactant by 8 hours of age, were <20 hours old, and had been ventilated for <12 hours. Outcome Measures. Primary outcome variables were BPD at 28 days and 36 weeks of postconceptional age. Secondary outcome variables were survival, gas exchange, airway pressures, airleak, intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), and other nonpulmonary complications. RESULTS: A total of 130 patients were included in the final analysis; 65 were randomized to HFJV and 65 to CV. The groups were of comparable birth weight, gestational age, severity of illness, postnatal age, and other demographics. The incidence of BPD at 36 weeks of postconceptional age was significantly lower in babies randomized to HFJV compared with CV (20.0% vs 40.4%). The need for home oxygen was also significantly lower in infants receiving HFJV compared with CV (5.5% vs 23.1%). Survival, incidence of BPD at 28 days, retinopathy of prematurity, airleak, pulmonary hemorrhage, grade I-II IVH, and other complications were similar. In retrospect, it was noted that the traditional HFJV strategy emphasizing low airway pressures (HF-LO) rather than the prescribed optimal volume strategy (HF-OPT) was used in 29/65 HFJV infants. This presented a unique opportunity to examine the effects of different HFJV strategies on gas exchange, airway pressures, and outcomes. HF-OPT was defined as increase in positive end-expiratory pressure (PEEP) by >/=1 cm H2O from pre-HFJV baseline and/or use of PEEP of >/=7 cm H2O. Severe neuroimaging abnormalities (PVL and/or grade III-IV IVH) were not different between the CV and HFJV infants. However, there was a significantly lower incidence of severe IVH/PVL in HFJV infants treated with HF-OPT compared with CV and HF-LO. Oxygenation was similar between CV and HFJV groups as a whole, but HF-OPT infants had better oxygenation compared with the other two groups. There were no differences in PaCO2 between CV and HFJV, but the PaCO2 was lower for HF-LO compared with the other two groups. The peak inspiratory pressure and DeltaP (peak inspiratory pressure-PEEP) were lower for HFJV infants compared with CV infants. CONCLUSIONS: HFJV reduces the incidence of BPD at 36 weeks and the need for home oxygen in premature infants with uncomplicated RDS, but does not reduce the risk of acute airleak. There is no increase in adverse outcomes compared with CV. HF-OPT improves oxygenation, decreases exposure to hypocarbia, and reduces the risk of grade III-IV IVH and/or PVL.

Bronchopulmonary Dysplasia↗
PubMed1994

Treatment of persistent pulmonary hypertension of the newborn without hyperventilation: an assessment of diffusion of innovation.

OBJECTIVE: The treatment of neonates with persistent pulmonary hypertension of the newborn (PPHN) is controversial with no consensus on diagnostic criteria or treatments. Hyperventilation has been the therapeutic mainstay. However, two widely variant alternative approaches have been proposed: ventilation without induced alkalosis, or more aggressive therapies such as high frequency ventilation or extracorporeal membrane oxygenation. We wished to determine the extent to which these alternative treatments have diffused into practice. METHODS: A forced choice questionnaire was mailed to a sample representing 10% of 3740 practicing neonatologists. Sixty percent of those surveyed responded. Data on treatment practices was tabulated. Subanalyses with respect to training era, practice site, and geographic region were performed. RESULTS: In patients with meconium aspiration syndrome, without evidence of PPHN, 36% described their initial management as hyperventilation. If PPHN was confirmed, hyperventilation was used in 90% of patients by 44% of the respondents. Muscular paralysis and inotropic support were also used frequently. Alkali and vasodilator infusion were used less frequently. The gentle ventilation strategy proposed by Wung and James at Columbia Babies Hospital was used infrequently by 47% of respondents. Gentle ventilation was used more frequently by board-certified neonatologists than those not certified. No significant differences in practice were identified by geographic region or era of training. When standard treatment failed, only 40% of the respondents utilized rescue treatments such as high frequency ventilation or extracorporeal membrane oxygenation. CONCLUSIONS: This study documents that gentle ventilation, an easily and inexpensively adopted innovation, has not diffused into practice significantly while more expensive high technology treatments, such as high frequency ventilation and extracorporeal membrane oxygenation, have penetrated more significantly.

Diffusion of Innovation↗
PubMed1993

Ultrasound guidance of suprapubic bladder aspiration in neonates.

We performed a prospective, randomized trial comparing ultrasound guidance of suprapubic bladder aspiration with unguided aspiration. The acquisition of urine improved with ultrasound guidance from 60% to 96.4%. The number of needle insertions decreased and the amount of urine obtained increased. Ultrasonography is a useful tool for bladder aspiration.

Drainage↗
PubMed1993

Extracorporeal membrane oxygenation: an adjunct in the management of the neonate with severe respiratory distress and congenital urinary tract anomalies.

Severe respiratory distress is the major cause of perinatal mortality associated with congenital urinary tract anomalies or severe obstructive uropathy, and is often accompanied by oligohydramnios. In the past the prognosis in these high risk cases was extremely poor. We review our recent experience in 3 neonates with severe respiratory distress and congenital urinary tract anomalies who were successfully managed with extracorporeal membrane oxygenation, of whom 2 had posterior urethral valves and 1 had bilateral solid renal dysplasia. The use of extracorporeal membrane oxygenation for life threatening respiratory distress in the neonate associated with congenital uropathy is not limited to our experience. A review of the National Neonatal Extracorporeal Membrane Oxygenation Registry for neonates with urological indications for extracorporeal membrane oxygenation revealed 10 interventions with 9 survivors, for a survival rate of 90%. Extracorporeal membrane oxygenation may provide cardiopulmonary support during a period of immature circulation, allowing pulmonary parenchymal and vascular maturation as well as preventing iatrogenic barotrauma.

Extracorporeal Membrane Oxygenation↗
PubMed1992

A prospective, multicenter, randomized study of high versus low positive end-expiratory pressure during extracorporeal membrane oxygenation.

To test the hypothesis that increased positive end-expiratory pressure (PEEP) could prevent deterioration of pulmonary function and lead to more rapid recovery of lung function, we randomly assigned 74 patients undergoing extracorporeal membrane oxygenation (ECMO) at four centers to receive either high (12 to 14 cm H2O) or low (3 to 5 cm H2O) PEEP. The two groups were similar in terms of weight, gestational age, diagnosis, and pre-ECMO course. All other aspects of care were identical. Dynamic lung compliance was measured at baseline and every 12 hours. Radiographs of the chest were obtained daily. Survival rates were similar in the two groups: 36 of 40 for low PEEP and 34 of 34 for high PEEP. The duration of ECMO therapy was 97.4 +/- 36.3 hours in the high-PEEP group and 131.8 +/- 54.5 hours in the low-PEEP group (p less than 0.01). Dynamic lung compliance throughout the first 72 hours of ECMO was significantly higher in patients receiving high PEEP. Radiographic appearance of the lungs correlated well with lung compliance: patients receiving high PEEP had significant deterioration of the radiographic score less frequently than those receiving low PEEP. High PEEP also was associated with significantly fewer complications. We conclude that PEEP of 12 to 14 cm H2O safely prevents deterioration of pulmonary function during ECMO and results in more rapid lung recovery than traditional lung management with low PEEP.

Extracorporeal Membrane Oxygenation↗
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↗