Mechanical Ventilation In Preterm Infants Research Articles

Increased incidence of sighs (augmented inspiratory efforts) during synchronized intermittent mandatory ventilation (SIMV) in preterm neonates

A reflex resulting in a deep, sigh-like inspiratory effort (augmented breath) is frequently triggered during synchronized mechanical ventilation in preterm infants. We studied the incidence of augmented inspiratory efforts and their effect on ventilation and lung compliance during conventional IMV and synchronized IMV (SIMV) in 15 preterm neonates (GA 26.7 +/- 1.5 wks (mean +/- SD), BW 925 +/- 222 g, age 1-8 days). Augmentation of spontaneous inspiratory effort was defined as an esophageal pressure deflection occurring coincident with a synchronized mechanical breath and exceeding the previous unassisted spontaneous effort by more than 50%. The incidence of augmented breaths was higher during SIMV (11.1 +/- 7.7%; P < 0.01) than during conventional IMV (5.1 +/- 6.1%). However, when the synchronized breaths were triggered late (200-300 msec) after the onset of inspiration, augmented breaths occurred no more frequently than during conventional IMV (6.0 +/- 4.7%). The incidence of augmented breaths correlated inversely with dynamic lung compliance (P = 0.014), but was not significantly influenced by a change in PEEP. Although inspiratory effort increased nearly three times during the augmented breaths, tidal volume increased only 12%. The change in tidal volume was limited because the augmented effort reached its maximal negativity only approximately 500 ms after the beginning of the synchronized, mechanical breath and at a time when the mechanical breath had already ended. For this reason the augmented effort did not contribute significantly to minute ventilation, but only prolonged inspiration. Dynamic lung compliance did not change significantly after an augmented breath. The results indicate that augmented inspiratory efforts are more common in preterm neonates ventilated with SIMV than with conventional IMV, but do not contribute significantly to ventilation.

Early continuous positive pressure in the labor room

Indication for intubation and mechanical ventilation in premature infants may be reduced by initiating continuous positive airway pressure (CPAP) in delivery room. Immediately after birth, respiratory support with CPAP was given to all infants with gestational age less than 32 weeks. In case of apnea or progressing symptoms with hypoxemia or carbonic acidosis, with PCO2 increasing to more than 60 mmHg, infants were treated with nasotracheal intubation and ventilation. One hundred and fifty one infants, with mean gestational age 29.6 +/- 1.9 weeks and mean birth weight 1,326 +/- 378 g were delivered in the obstetrical department of Marseille. In delivery room, 63% were treated with CPAP, and only 13% with nasotracheal intubation. The need for subsequent mechanical ventilation was reduced to 40% of the population. Surfactant therapy was used in 17% of this cohort. Two infants were given surfactant and extubated. Three of 14 deaths (9.2%) were caused by respiratory disease. Early CPAP reduces the indication of mechanical ventilation in premature infants. Incidence of pulmonary complications such as pneumothorax or bronchopulmonary dysplasia is low among those infants who require mechanical ventilation later. Early CPAP takes place in a general policy to decrease neonatal morbidity.

Influence of energy substrates on respiratory gas exchange during conventional mechanical ventilation of preterm infants

Objective: The purpose of this study was to determine the optimal parenteral feeding regimen for infants with compromised respiratory function. Methods: We studied the influence of varying the source of energy on respiratory gas exchange in 10 infants who were supported by mechanical ventilation and who received intravenous feedings. Two isoenergetic parenteral regimens were infused consecutively; the level of fat intake was varied inversely with that of glucose. Under similar ventilator settings, transcutaneous partial pressures of oxygen and carbon dioxide, as well as indirect calorimetry were measured during each regimen. Results: Despite the higher carbon dioxide production during the glucose-rich regimen (8.9 ± 0.7 vs 7.9 ± 0.4 ml/kg per minute, p <0.05 by analysis of variance), transcutaneous partial pressure of carbon dioxide remained unaffected, suggesting ventilatory compensation as documented by the increased ( p <0.002) alveolar ventilation. This was not associated with a detectable rise in oxygen consumption, but with a significant change in partial pressure of oxygen (77 ± 5 vs 66 ± 3 mm Hg, p <0.05). Conclusions: Ventilator-dependent infants with early and mild bronchopulmonary dysplasia, who receive intravenous feedings of a moderate load of glucose-based energy, can compensate for enhanced carbon dioxide production by increasing their respiratory drive, with a beneficial effect on oxygenation compared with that observed when energy is derived from lipid-based solutions. ( J PEDIATR 1995;126:619-24)

A multicenter randomized trial of high frequency oscillatory ventilation as compared with conventional mechanical ventilation in preterm infants with respiratory failure

A multicenter randomised trial was conducted in nine neonatal centers in Japan to re-evaluate the safety and the efficacy of high frequency oscillatory ventilation using the piston type oscillator (Hummingbird) in the treatment of respiratory failure in preterm infants weighing between 750 and 2000 g at birth. A total of 92 infants were enrolled in the study. Forty-six infants were allocated to high frequency oscillatory ventilation and 46 infants to conventional mechanical ventilation. There were no differences in sex, birth weight, gestation and Apgar score between groups. The study was begun 2.0 ± 1.6 h (mean ± S.D.) after birth in the high frequency oscillation group and 1.7 ± 1.5 h after birth in the conventional mechanical ventilation group. The absence of intraventricular hemorrhage was confirmed by echography in all cases before beginning ventilation. Mortality was similar in high frequency oscillatory ventilation and conventional mechanical ventilation (0 and 2%). The incidence of intraventricular hemorrhage was also similar in the high frequency and conventional mechanical ventilation groups (15 and 13% overall; 4 and 2% in grades III and IV, respectively). Nine percent of the infants in high frequency oscillatory ventilation and 13% in conventional mechanical ventilation developed bronchopulmonary dysplasia, but the difference was not significant. The frequency of air leaks was also equal in both groups. Periventricular leukomalacia was detected in 9% of infants on conventional mechanical ventilation and 2% on high frequency oscillation, but the difference was not significant. Mean airway pressure was significantly higher in the high frequency oscillatory ventilation group and the infants on high frequency oscillation showed a significantly higher arterial to alveolar oxygen tension ratio after 6 h of treatment. These results suggest that high frequency oscillatory ventilation does not increase the risk of severe complications such as air leaks, intraventricular hemorrhage or periventricular leukomalacia when it is used by experienced neonatologists. Indeed high frequency oscillatory ventilation helps provide better oxygenation with higher mean airway pressure without increasing the risk of bronchopulmonary dysplasia and severe complications such as air leaks and intraventricular hemorrhage.

Spontaneous Pneumopericardium in an Otherwise Healthy Full‐term Newborn

Neonatal pneumopericardium is usually a complication of mechanical ventilation in premature infants with respiratory distress syndrome. We report a full-term neonate who developed pneumopericardium after forceps delivery and mild asphyxia. The child was never ventilated and had no signs of parenchymal lung disease. The pneumopericardium resolved spontaneously. Although drainage of pneumopericardium is usually recommended, this may not always be necessary when there are no signs of cardiac tamponade.

Air Embolism From Mechanical Ventilation in Respiratory Distress Syndrome

Three cases of air embolism secondary to mechanical ventilation in premature infants with respiratory distress syndrome are presented, and its mechanism is discussed. A plausible mechanism for air in the hepatic veins occurring in most of these cases is also discussed. Many sudden unexplained deaths in premature infants on mechanical ventilation may be due to air embolism, which should be recognized as a component of neonatal "air-block syndrome."