Volume-controlled intermittent mandatory ventilation in preterm infants with hypoxemic episodes. Effects of volume-guaranteed synchronized intermittent mandatory ventilation in preterm infants recovering from respiratory failure. Impact of targeted-volume ventilation on lung inflammatory response in preterm infants with respiratory distress syndrome (RDS). Patient-initiated, pressure-regulated, volume-controlled ventilation compared with intermittent mandatory ventilation in neonates: a prospective, randomised study. Randomised trial of volume controlled versus time cycled, pressure limited ventilation in preterm infants with respiratory distress syndrome. Long term follow-up of very low birthweight infants from a neonatal volume versus pressure mechanical ventilation trial. Effects of volume-targeted synchronized intermittent mandatory ventilation on spontaneous episodes of hypoxemia in preterm infants. Pressure-regulated volume control ventilation vs synchronized intermittent mandatory ventilation for very low-birth-weight infants: a randomized controlled trial. Impact of volume guarantee ventilation on arterial carbon dioxide tension in newborn infants: a randomised controlled trial. Volume guarantee: stability of tidal volume and incidence of hypocarbia. Is there an advantage of using pressure support ventilation with volume guarantee in the initial management of premature infants with respiratory distress syndrome? A pilot study.
To test the hypothesis in ventilated very low birth weight infants with frequent hypoxemic episodes that volume-controlled synchronized intermittent mandatory ventilation (SIMV) vs. pressure-controlled SIMV reduces by at least 20% the time with hypoxemia (defined as SpO(2)<80%).
                Randomized cross-over design.
                University-based tertiary neonatal intensive care unit.
                15 mechanically ventilated very low birth weight infants with frequent hypoxemic episodes.
                The infants were exposed in random order to volume-controlled and pressure-controlled SIMV for 4 h each. The target tidal volume during volume-controlled SIMV was matched to the tidal volume measured during pressure-controlled SIMV. FIO(2) was adjusted using uniform criteria to maintain SpO(2) within the target range (SpO(2) 80-92%).
                Primary outcome measure was the time with an SpO(2)<80%. Although tidal volume was maintained better during desaturations with volume-controlled SIMV, there was neither a significant difference in time with an SpO(2)<80% (expressed as proportion of total experimental time; median, interquartile range)-volume-control 10.6% (9.2-13.7%) vs. pressure-control 10.8% (8.3-13.3%)-nor in FIO(2) exposure. During volume-controlled SIMV the infants spent less time with an SpO(2) above the target range and had fewer associated bradycardias.
                Volume-controlled SIMV did not decrease the time with an SpO(2)<80%, although tidal volume was better maintained during these episodes and bradycardias were less frequent than with pressure-controlled SIMV in this population of very low birth weight infants with frequent hypoxemic episodes. Volume guarantee (synchronized intermittent mandatory ventilation [SIMV]+VG) is a novel mode of SIMV for automatic adjustment of the peak inspiratory pressure to ensure a minimum set mechanical tidal volume (V(T mech)). The objective of this study was to compare the effects of SIMV+VG with conventional SIMV on ventilation and gas exchange in a group of very low birth weight infants recovering from acute respiratory failure.
                Nine infants were initially studied during 2 consecutive 60-minute ventilatory modalities of conventional SIMV (ventilator settings by clinical team) and SIMV+VG 4.5 (V(T mech) set at 4.5 mL/kg) in random order. Eight additional infants were studied during the same ventilatory modalities plus 1 additional epoch consisting of SIMV+VG 3.0 (V(T mech) set at 3.0 mL/kg).
                Peak inspiratory pressure was significantly lower during SIMV+VG 3.0. Mean airway pressure, V(T mech), number of large V(T mech) (>7 mL/kg), and mechanical minute ventilation (V'(E)) were reduced during SIMV+VG 4.5 compared with SIMV and were further reduced during SIMV+VG 3.0. Spontaneous V'(E) increased during SIMV+VG 4.5 and was even higher during SIMV+VG 3.0. The resulting total V'(E) was higher during both SIMV+VG modes compared with SIMV. Arterial oxygen saturation by pulse oximetry, transcutaneous carbon dioxide tension, and fraction of inspired oxygen did not differ significantly, although transcutaneous carbon dioxide tension increased slightly during SIMV+VG 3.0.
                The short-term use of SIMV+VG resulted in automatic weaning of the mechanical support and enhancement of the spontaneous respiratory effort while maintaining gas exchange relatively unchanged in comparison to conventional SIMV. Volutrauma and pulmonary inflammation are thought to be the most important predisposing factors of chronic lung disease (CLD), a major complication of prematurity. A new option in patient-triggered ventilation (PTV), the volume guarantee (VG), a volume-targeted ventilation, seems to be a promising approach in reducing the risk of CLD, by limiting lung inflammatory injury and volutrauma. Our aim was to evaluate lung inflammatory response in preterm infants with respiratory distress syndrome (RDS), mechanically ventilated with and without VG, as measured by proinflammatory cytokines (IL-6, IL-8, and TNF-alpha) in tracheobronchial aspirate (TA) fluid. Fifty-three preterm infants (GA = 25-32 weeks) with RDS were randomized at birth to be ventilated using pressure support ventilation (PSV) with VG (Vt = 5 ml/kg) (n = 30) and without VG (n = 23) (Draeger Babylog 8000 Plus, 5.n). IL-6, IL-8, and TNF-alpha were determined by ELISA in TA samples on days 1, 3, and 7 of life. We observed a significant difference (ANOVA) in IL-8 and IL-6 levels on day 3 between the two groups (P < 0.05), and an increasing significative trend in IL-8 values in PSV group (P < 0.05). Mechanical ventilation lasted longer in the PSV group (12.3 +/- 3 vs. 8.8 +/- 3 days) (P = no significance). In conclusion, these preliminary data suggest a role for volume-targeted ventilatory strategy in reducing acute inflammatory response in preterm infants with RDS. Further studies are required in order to define whether this ventilatory strategy prevents lung injury.
                Copyright 2004 Wiley-Liss, Inc. To compare the effects of patient-initiated, pressure-regulated, volume-controlled ventilation (PRVC) with pressure-preset intermittent mandatory ventilation (IMV) in neonates with respiratory failure.
                Randomised, prospective study.
                Intensive care unit (14 beds) in a 300-bed paediatric teaching hospital.
                60 neonates with respiratory distress syndrome (RDS) or congenital pneumonia, weighing < 2500 g and requiring mechanical ventilation.
                Ventilatory support until extubation via either IMV (n = 30) or PRVC (n = 27). In PRVC, the tidal volume (VT) was preset and pressure-controlled breaths delivered with peak inspiratory pressure values adapted to achieve the preset VT.
                Main outcome measures were duration of ventilation and incidence of bronchopulmonary dysplasia (BPD). Pulmonary air leaks and intraventricular haemorrhage (IVH) were considered major adverse effects. Demographic data, ventilation parameters and arterial/alveolar oxygen tension ratio were similar at randomisation. Duration of ventilation and incidence of BPD were not decreased by the use of PRVC. Air leaks occurred in 3 neonates in the PRVC group and in 7 babies treated with IMV (NS). The incidence of IVH grade > II was lower in babies treated with PRVC (p < 0.05). In a subgroup of neonates weighing < 1000 g, the duration of ventilation and incidence of hypotension were reduced in the PRVC group (p < 0.05).
                Patient-initiated, pressure-regulated, volume-controlled ventilation can be safely used in neonates and may contribute to a lower incidence of complications. Fifty preterm infants weighing 1200 g or more with clinical and radiographic evidence of respiratory distress syndrome, requiring both mechanical ventilation and exogenous surfactant replacement, were randomly allocated to receive either volume controlled ventilation or time cycled, pressure limited ventilation. Tidal volume delivery in each group was deliberately controlled at 5-8 ml/kg so that the only difference between the two groups was the ventilatory modality, the manner in which tidal volume was delivered. The rest of the ventilatory management and clinical care was done according to protocol. The two modes of ventilation were compared by determining the time required to achieve pre-determined success criteria, based on either the alveolar-arterial oxygen gradient or the mean airway pressure as a standard against which the speed of weaning could be objectively assessed. Infants randomised to volume controlled ventilation met success criteria sooner and had a shorter duration of mechanical ventilation. These babies also had a significantly lower incidence of intraventricular haemorrhages and abnormal periventricular echodensities on ultrasound scans. Volume controlled ventilation seems to be both safe and effective in this group of patients. A previous randomised trial showed volume controlled ventilation (VCV) was efficacious in ventilating very preterm and extremely low birthweight babies.
                To compare long term survival, pulmonary morbidities and gross neurodevelopmental outcomes of babies randomised to either VCV or pressure limited ventilation (PLV) for treatment of respiratory distress syndrome.
                Masked evaluation of health status, including frequency of respiratory illness, use of medications, hospital admissions, and gross neurodevelopmental status were obtained using a structured parental questionnaire and verification from medical records.
                94 of 109 children (86%) survived to discharge. Three died after discharge (2 VCV, 1 PLV). Modality of ventilation did not affect overall mortality; seven VCV children died (12%) versus 11 PLV (21%) (OR 0.5 (95% CI 0.1 to 1.4), p = 0.13). Respiratory abnormalities were present in 32 (37%), and 26 (30%) required hospital readmission. There was no significant difference in readmission rates between the two groups: VC 13/45 (29%) and PLV 19/40 (47%) (OR 0.4 (0.1 to 1.1), p = 0.07). Modality of ventilation did not affect frequency of respiratory illness: VC 12 (27%) and PLV 14 (35%) (OR 0.46 (0.1 to 1.1), p = 0.09). However, significantly fewer VCV children (13%, n = 6) compared to PLV children (32%, n = 13) required treatment with inhaled steroids/bronchodilators (OR 0.3 (0.1 to 0.9), p = 0.04). Nine children had severe neurodevelopmental disability (cerebral palsy, blindness, deafness) (9.8%; 3 VCV, 6 PLV 6) (OR 0.4 (0.09 to 1.7)).
                The efficacy of VCV in very preterm and low birth babies appears to be maintained on longer term evaluation. BACKGROUND: Hypoxemic episodes in ventilated preterm infants are frequently caused by reduced ventilation due to a decrease in lung volume and acute worsening of respiratory mechanics. OBJECTIVE: To compare the efficacy of conventional time-cycled, pressure-limited flow synchronized intermittent mandatory ventilation (SIMV) and volume-targeted SIMV (VT-SIMV) in reducing the frequency and severity of these episodes. METHODS: SIMV and VT-SIMV were compared in preterm infants with frequent spontaneous episodes of hypoxemia. VT-SIMV was provided with the Draeger Babylog 8000plus ventilator in volume-guarantee mode. Results: In all, 32 infants (birth weight 668 +/- 126 g, gestational age 24.8 +/- 1.1 weeks, age 37.5 +/- 17.3 days) were studied during 2-hour periods of SIMV and VT-SIMV in random sequence. In an initial phase, a group of 12 infants was supported during VT-SIMV with a target tidal volume of 4.5 ml/kg (VT-SIMV 4.5). A planned interim analysis did not show differences in frequency and duration of hypoxemia between VT-SIMV 4.5 and SIMV, and the initial phase was stopped. In a second phase of the study, 20 infants were studied while supported with a target tidal volume of 6.0 ml/kg during VT-SIMV (VT-SIMV 6.0). In the second phase of the study, the frequency of the hypoxemic episodes did not change but the mean episode duration was shorter during VT-SIMV compared to SIMV. The proportion of mechanical breaths with small tidal volumes (< or =3 ml/kg) was reduced during VT-SIMV 6.0 versus SIMV, while the peak inspiratory pressure and mean airway pressure were increased. Conclusion: VT-SIMV did not reduce the frequency of hypoxemic episodes, but VT-SIMV 6.0 was effective in reducing the duration of the hypoxemic episodes. To test the hypothesis that pressure-regulated volume control (PRVC), an assist/control mode of ventilation, would increase the proportion of very low-birth-weight infants who were alive and extubated at 14 days of age as compared with synchronized intermittent mandatory ventilation (SIMV).
                Ventilated infants with birth weight of 500 to 1249 g were randomized at less than 6 hours of age either to pressure-limited SIMV or to PRVC on the Servo 300 ventilator (Siemens Electromedical Group, Danvers, Mass). Infants received their assigned mode of ventilation until extubation, death, or meeting predetermined failure criteria.
                Mean +/- SD birth weights were similar in the SIMV (888 +/- 199 g, n = 108) and PRVC (884 +/- 203 g, n = 104) groups. No differences were detected between SIMV and PRVC groups in the proportion of infants alive and extubated at 14 days (41% vs 37%, respectively), length of mechanical ventilation in survivors (median, 24 days vs 33 days, respectively), or the proportion of infants alive without a supplemental oxygen requirement at 36 weeks' postmenstrual age (57% vs 63%, respectively). More infants receiving SIMV (33%) failed their assigned ventilator mode than did infants receiving PRVC (20%). Including failure as an adverse outcome did not alter the overall outcome (39% of infants in the SIMV group vs 35% of infants in the PRVC group were alive, extubated, and had not failed at 14 days).
                In mechanically ventilated infants with birth weights of 500 to 1249 g, using PRVC ventilation from birth did not alter time to extubation. To compare the effects of the two modes of ventilation, synchronous intermittent positive pressure ventilation (SIPPV) and SIPPV with Volume Guarantee (VG), on arterial carbon dioxide tension (PaCO(2)) immediately after neonatal unit admission.
                Randomised study of ventilation mode for premature inborn infants admitted to two tertiary neonatal units. After admission, infants were randomised to receive either SIPPV or VG using a Dräger Babylog 8000 plus ventilator. In the SIPPV group, peak airway pressure was set clinically. In the VG group, desired tidal volume was set at 4 ml/kg, with the ventilator adjusting peak inspiratory pressure to deliver this volume. The study was completed once the first arterial PaCO(2) was available, with the desirable range defined as 5-7 kPa.
                PaCO(2) was significantly higher in the VG group (VG: 5.7 kPa, SIPPV: 4.9 kPa; p=0.03). The VG group had fewer out-of-range PaCO(2) values (VG: 42%, SIPPV: 57%) and fewer instances of hypocarbia <5 kPa (VG: 32%, SIPPV: 57%) but neither difference achieved statistical significance. Regression analysis showed PaCO(2) was negatively correlated with gestation (r=-0.41, p=0.01) and also with the mode of ventilation (r=0.32, p<0.05). In the VG group, all infants 23-25 weeks' gestation had out-of-range PaCO(2) values. VG significantly reduced the incidence of out-of-range PaCO(2) and hypocarbia in infants over 25 weeks' gestation (VG: 27%, SIPPV: 61%; p<0.05).
                Using this strategy, VG appears feasible in the initial stabilisation of infants over 25 weeks' gestation, with a halving of the incidence of hypocarbia. In the small number of babies studied below this gestation, VG was not found to be effective. Excessive tidal volume (V(T)) can lead to lung injury, hypocarbia, and neurologic damage. Volume guarantee (VG) uses exhaled V(T) as the control variable to reduce the risk of volutrauma and more closely control PaCO(2). Our objective was to test the hypothesis that VG combined with assist/control (A/C) will maintain PaCO(2) and V(T) within target range more consistently than assist/control alone during the first 72 hr of life in ventilated preterm infants. Eligible infants were randomly assigned to A/C + VG or A/C alone. Data were recorded directly from the pressure and volume module of the Draeger Babylog 8000+ ventilator. Arterial blood gases were obtained every 2-6 hr, as clinically indicated. In A/C, inspiratory pressure was adjusted to achieve a V(T) of 4-6 ml/kg. In VG, the target V(T) was 5 ml/kg. Subsequent adjustments were made by the clinical team in response to arterial blood gas measurements (ABG). Proportion of breaths and PaCO(2) values outside the target range were compared by chi(2), and continuous variables by t-test. There were no differences in demographic or baseline ventilator variables between the 18 infants in the two groups. For 1,805/11,950 breaths (15.1%), V(T) was > target with A/C + VG, vs. 2,503/9,853 (25.4%) with A/C (P < 0.001). V(T) was < target for 21.7% of breaths with A/C + VG, vs. 35.7% with A/C (P < 0.001). Twenty percent of PaCO(2) values were < target, with A/C + VG vs. 36.3% with A/C, P < 0.05. The proportion of PaCO(2) values > target was similar in the two groups. Oxygenation and mean pH were not different. No complications related to mechanical ventilation were observed. In conclusion, VG significantly reduced hypocarbia and excessively large V(T). This suggests the potential to reduce pulmonary and neurologic complications of mechanical ventilation. Larger studies are needed to establish safety and demonstrate such benefits.
                Copyright 2004 Wiley-Liss, Inc. To evaluate the feasibility of using the pressure support ventilation with volume guarantee (PSV-VG) as an initial ventilatory mode in preterm infants with respiratory distress syndrome (RDS) after surfactant treatment to achieve accelerated weaning of peak inspiratory pressure (PIP) and mean airway pressure (MAP).
                Initial 24-hour ventilatory parameters were compared in two groups of preterm infants managed by PSV-VG and the synchronized intermittent mandatory ventilation (SIMV) mode in a randomized controlled pilot study after surfactant treatment for RDS. A total of 16 babies were randomized to PSV-VG (1198+/-108 g [mean+/-SEM]; 27.9+/-0.6 weeks) and 18 babies to SIMV (birth weight 1055+/-77 g; gestational age 27.4+/-0.5 weeks). Repeated measures analysis of variance was used to compare serial values of PIP and MAP in the two groups.
                The PIP and MAP decreased over time (p<0.001) during the first 24 hours after surfactant administration in both groups but the decrease in MAP was faster in the SIMV group compared to PSV-VG group (p=0.035). The median numbers of blood gases during the first 24 hours were four and two in the SIMV and PSV-VG groups, respectively (p<0.001). The overall outcomes were not significantly different between the two groups.
                PSV-VG did not offer any ventilatory advantage over SIMV in the initial management of surfactant-treated premature newborns with RDS except for minimizing the number of blood gases.
Infants ventilated using VTV modes had reduced death and chronic lung disease compared with infants ventilated using PLV modes. Further studies are needed to identify whether VTV modes improve neurodevelopmental outcomes and to compare and refine VTV strategies.