Pressure-regulated volume control vs volume control ventilation in infants after surgery for congenital heart disease.

The objective of this investigation was to compare how two modes of positive pressure ventilation affect cardiac output, airway pressures, oxygenation, and carbon dioxide removal in children with congenital heart disease in the immediate postoperative period. The investigation used a one group pretest-post-test study design and was performed in the pediatric cardiac intensive care unit in a university-affiliated children's hospital. Nine infants were enrolled immediately after repair of tetralogy of Fallot (2) or atrioventricular septal defects (7) with mean weight = 5.5 kg (4.2-7.3 kg). Children were admitted to the pediatric cardiothoracic intensive care unit after complete surgical repair of their cardiac defect and stabilized on a Siemen's Servo 300 ventilator in volume control mode (VCV1) (volume-targeted ventilation with a square flow wave pattern). Tidal volume was set at 15 cc/kg (total). Hemodynamic parameters, airway pressures and ventilator settings, and an arterial blood gas were measured. Patients were then changed to pressure-regulated volume control mode (PRVC) (volume-targeted ventilation with decelerating flow wave pattern) with the tidal volume set as before. Measurements were repeated after 30 minutes. Patients were then returned to volume control mode (VCV2) and final measurements made after 30 minutes. The measurements and results are as follows: After correction of congenital heart defects in infants, mechanical ventilation using a decelerating flow wave pattern resulted in a 19% decrease in peak inspiratory pressure without affecting hemodynamics, arterial oxygenation, or carbon dioxide removal.

Diastolic function in neonates after the arterial switch operation: effects of positive pressure ventilation and inspiratory time.

OBJECTIVE: To determine the effects positive pressure ventilation have on left ventricular diastolic function in neonates after the arterial switch operation. DESIGN: Prospective case series. SETTING: Pediatric cardiac and multidisciplinary intensive care units in two university-affiliated children's hospitals. PATIENTS AND PARTICIPANTS: The patient population consisted of 12 neonates weighing 2.5-4.2 kg with D-transposition of the great arteries (DTGA) who underwent arterial switch operation. INTERVENTIONS: All patients were mechanically ventilated in a volume-targeted mode with a square wave flow pattern. The positive end-expiratory pressure was held constant. A long inspiratory time was set by extending it over three cardiac cycles. MEASUREMENTS AND RESULTS: Pulsed Doppler measurements of left ventricular diastolic function were performed during the following cardiac cycles: (1) the last diastolic period of expiration (E(L)), (2) first, second and third diastolic periods of inspiration (I1, I2, I3) and (3) the first diastolic period of expiration (E(F)). Doppler measurements of peak E wave, peak A wave, E area/A area, E area fraction, A area fraction, 0.33 area fraction and the deceleration time were made. Doppler tracings were digitized and the data obtained from three sequential study periods were averaged. Data were statistically analyzed using the repeated measures analysis of variance procedure. During (I1), there was a 21% increase in the peak E wave (0.53+/-0.06 vs 0.64+/-0.08 m/s, p < 0.01) and 28% increase in peak A wave (0.47+/-0.07 vs 0.60+/-0.08 m/s, p < 0.01) compared to (E(L)). There was a 24% increase in total area under the E and A waves when I1 was compared to E(L) (0.059+/-0.008 vs 0.073+/-0.009, p < 0.01) and there was no change in mitral valve deceleration time. Compared to the initial diastolic period during inspiration (I1), the third diastolic period during inspiration (I3) had a 38% decrease in peak E (0.64+/-0.08 vs 0.40+/-0.05 m/s, p < 0.01) and 33% decrease in peak A (0.60+/-0.09 vs 0.40+/-0.05 m/s, p < 0.01). In addition, there was a 16% reduction in total area under the E and A waves (0.073+/-0.009 vs 0.061+/-0.008, p < 0.01). There were no changes in the other diastolic indexes that reflect changes in ventricular compliance or relaxation. CONCLUSIONS: In neonates with transposition of the great arteries (TGA) after the arterial switch operation, positive pressure ventilation augments left ventricular filling during the early phase of inspiration. Prolonging the inspiratory time over three cardiac cycles results in a reduction in left ventricular filling during the third diastolic period. There were no changes in the other diastolic indexes that reflect changes in ventricular compliance or relaxation.

Lipids and stability of menopausal status in middle-aged women within two years.

In the whole population total cholesterol (TC) was unchanged within two years. The triglyceride (TG) level increased significantly, but HDLC increased too between 1996 and 1998. The increase of TG concentration was significantly in the stable group only, whereas the increase of HDLC concentration was observed in both groups. "Depressed mood" and "anxiety" seem to have a positive influence on the TC levels.

High-frequency oscillatory ventilation in pediatric respiratory failure: a multicenter experience.

OBJECTIVE: The use of high-frequency oscillatory ventilation (HFOV) has increased dramatically in the management of respiratory failure in pediatric patients. We surveyed ten pediatric centers that frequently use high-frequency oscillation to describe current clinical practice and to examine factors related to improved outcomes. DESIGN: Retrospective, observational questionnaire study. SETTING: Ten tertiary care pediatric intensive care units. PATIENTS: Two hundred ninety patients managed with HFOV between January 1997 and June 1998. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were classified according to presence or absence of preexisting lung disease, symptomatic respiratory syncytial virus infection, or presence of cyanotic heart disease or residual right-to-left intracardiac shunt. In addition, patients for whom HFOV acutely failed were analyzed separately. Those patients with preexisting lung disease were significantly smaller, had a significantly higher incidence of pulmonary infection as the triggering etiology, and had a significantly greater duration of conventional ventilation before institution of HFOV compared with patients without preexisting lung disease. Stepwise logistic regression was used to predict mortality and the occurrence of chronic lung disease in survivors. In patients without preexisting lung disease, the model predicted a 70% probability of death when the oxygenation index (OI) after 24 hrs was 28 in the immunocompromised patients and 64 in the patients without immunocompromise. In the immunocompromised patients, the model predicted a 90% probability of death when the OI after 24 hrs was 58. In survivors without preexisting lung disease, the model predicted a 70% probability of developing chronic lung disease when the OI at 24 hrs was 31 in the patients with sepsis syndrome and 50 in the patients without sepsis syndrome. In the patients with sepsis syndrome, the model predicted a 90% probability of developing chronic lung disease when the OI at 24 hrs was 45. CONCLUSIONS: Given the number of centers involved and the size of the database, we feel that our results broadly reflect current practice in the use of HFOV in pediatric patients. These results may help in deciding which patients are most likely to benefit from aggressive intervention by using extracorporeal techniques and may help identify high-risk populations appropriate for prospective study of innovative modes of supporting gas exchange (e.g., partial liquid breathing or intratracheal pulmonary ventilation).

Chest pain in pediatrics.

Chest pain in the pediatric population is a common and mostly benign occurrence. A thorough history and physical examination are usually all that are necessary in excluding the rare, life-threatening causes of chest pain. These rare, life-threatening events require immediate evaluation, treatment, and subspecialty consultation. Idiopathic chest pain is the most common diagnosis, and the symptoms are typically chronic. laboratory testing is usually nondiagnostic, costly, and burdensome to patients and therefore unnecessary. A long-term, trusting relationship with the patients and their families is needed to reassure them and allow symptoms to resolve.

Aortic arch complex anomalies: 20-year experience with symptoms, diagnosis, associated cardiac defects, and surgical repair.

To better understand the clinical presentation and surgical management of children with aortic arch complex anomalies ("vascular rings"), a retrospective study was performed on patients who presented to Children's National Medical Center between the years 1969 and 1989. A total of 59 patients were identified ranging in age at admission from birth to 14 years, of whom 35 (59%) were male and 24 (41%) female. Patients were classified into four major subtypes based on their surgical anatomy, with 29 (49%) patients having right aortic arch and left ductus/ligamentum arteriosus, 21 (36%) double aortic arch, 6 (10%) anomalous left pulmonary artery, and 3 (5%) arch artery anomaly (no ring); 19 patients (32%) had associated cardiac defects. The mean (+/-SD) age at onset of symptoms was 4.6 +/- 14.0 months, and the age at surgical repair was 18 +/- 34 months. There were no intraoperative mortalities, but two late deaths occurred. Three (5%) patients had a surgical complication. In contrast to previous studies, the incidence of nonring lesions was lower and associated cardiac defects higher. Forty-nine percent of patients had symptoms present at birth, and patients with associated cardiac disease did not present earlier than those without. In patients with right aortic arch and left ductus/ligamentum arteriosus, few had an anomalous left subclavian artery. Finally, equal dominance of the arches was most frequent in patients with double aortic arch. Aortic arch complex anomalies present symptomatically in a variety of ways, and noninvasive methods are used to identify the specific lesion and associated cardiac defects. Surgical repair is associated with low or no mortality in patients with uncomplicated aortic arch complex anomalies.

Ultrasound evaluation of piglet diaphragm function before and after fatigue.

Clinically, a noninvasive measure of diaphragm function is needed. The purpose of this study is to determine whether ultrasonography can be used to 1) quantify diaphragm function and 2) identify fatigue in a piglet model. Five piglets were anesthetized with pentobarbital sodium and halothane and studied during the following conditions: 1) baseline (spontaneous breathing); 2) baseline + CO2 [inhaled CO2 to increase arterial PCO2 to 50-60 Torr (6.6-8 kPa)]; 3) fatigue + CO2 (fatigue induced with 30 min of phrenic nerve pacing); and 4) recovery + CO2 (recovery after 1 h of mechanical ventilation). Ultrasound measurements of the posterior diaphragm were made (inspiratory mean velocity) in the transverse plane. Images were obtained from the midline, just inferior to the xiphoid process, and perpendicular to the abdomen. M-mode measures were made of the right posterior hemidiaphragm in the plane just lateral to the inferior vena cava. Abdominal and esophageal pressures were measured and transdiaphragmatic pressure (Pdi) was calculated during spontaneous (Sp) and paced (Pace) breaths. Arterial blood gases were also measured. Pdi(Sp) and Pdi(Pace) during baseline + CO2 were 8 +/- 0.7 and 49 +/- 11 cmH2O, respectively, and decreased to 6 +/- 1.0 and 27 +/- 7 cmH2O, respectively, during fatigue + CO2. Mean inspiratory velocity also decreased from 13 +/- 2 to 8 +/- 1 cm/s during these conditions. All variables returned to baseline during recovery + CO2. Ultrasonography can be used to quantify diaphragm function and identify piglet diaphragm fatigue.

Late follow-up of balloon angioplasty in children with a native coarctation of the aorta.

Between May 1984 and April 1993, 59 children underwent balloon angioplasty of a native coarctation at our institution. The follow-up protocol included a cardiac catheterization 1 to 2 years after angioplasty, which was performed in 90% of patients with > or = 2 years follow-up. Angioplasty caused an acute decrease in peak systolic gradient from 46 +/- 2 to 15 +/- 2 mm Hg, without early aneurysm or emergent surgical intervention in any patient. Based on follow-up data, a satisfactory result was obtained in 38 patients (64%; 70% confidence limit: 58% to 71%), defined as a residual systolic gradient < 20 mm Hg and no aneurysm. In these patients the gradient decreased acutely from 43 +/- 2 to 9 +/- 1 mm Hg, was 6 +/- 1 mm Hg at follow-up catheterization, and 9 +/- 2 mm Hg by clinical evaluation 4.4 +/- 0.3 years after angioplasty. Twenty-one patients (36%; 70% confidence limit: 29% to 42%) had an unsatisfactory result due to a residual gradient > or = 20 mm Hg (n = 19) or aneurysm formation (n = 3), or both. Restenosis occurred in 6 patients, and occurred more in infants than in children > or = 12 months of age (3 of 5 infants vs 3 of 41 children, p = 0.01). Thus, balloon angioplasty provides an effective initial treatment strategy for native coarctation in most children aged > 12 months.

High-frequency jet ventilation for respiratory failure after congenital heart surgery.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is considered when respiratory failure (RF) persists despite increasing conventional mechanical ventilation (CMV). High-frequency jet ventilation (HFJV) can improve ventilation with comparable mean airway pressure (PAW) to that found on CMV. This study was undertaken to determine whether HFJV is an effective treatment and alternative to ECMO for RF after congenital heart surgery. METHODS AND RESULTS: HFJV was instituted in nine patients ranging in age from 6 days to 3.3 years with congenital heart disease meeting pulmonary criteria for ECMO. Indications for HFJV were pulmonary hypertension (six), adult-type respiratory distress syndrome (two), and pneumonitis (one). Seven patients (77%) were placed on HFJV within 24 hours of operation, and two patients required HFJV 2 weeks after operation. HFJV resulted in resolution of RF in eight of nine patients (89%). After 1 hour of HFJV, the arterial pH increased from 7.40 +/- 0.1 to 7.56 +/- 0.1 (p < 0.05) and the PaCO2 decreased from 44 +/- 15 to 29 +/- 12 mm Hg (p < 0.05). During HFJV there was no change in PaO2, although the FIO2 decreased from 0.99 +/- 0.0 to 0.73 +/- 0.2 (p < 0.05). There was no change in PAW, peak inspiratory pressures, positive end-expiratory pressures, heart rate, or mean arterial blood pressure during HFJV when compared with CMV. Mean duration of HFJV was 43 hours. Four patients were extubated and discharged from the hospital. Two patients were extubated but died from sepsis. Two patients had resolution of RF, but one died at reoperation and one from multisystem organ failure. The patient who failed HFJV therapy was placed on ECMO and died. CONCLUSIONS: This study suggests that HFJV improves ventilation and is an alternative to ECMO in patients with RF after surgery for congenital heart disease.