High frequency oscillatory ventilation compared with conventional mechanical ventilation in adult respiratory distress syndrome: a randomized controlled trial [ISRCTN24242669]. The Provo multicenter early high-frequency oscillatory ventilation trial: improved pulmonary and clinical outcome in respiratory distress syndrome. Flow-cycled versus time-cycled sIPPV in preterm babies with RDS: a breath-to-breath randomised cross-over trial. Comparison of high-frequency chest wall oscillation and oscillating positive expiratory pressure in the home management of cystic fibrosis: a pilot study. [Noninvasive positive pressure ventilation for acute respiratory failure in chronic obstructive pulmonary disease in a general respiratory ward]. Prospective, randomized comparison of high-frequency oscillatory ventilation and conventional mechanical ventilation in pediatric respiratory failure. A prospective randomized, controlled trial comparing synchronized nasal intermittent positive pressure ventilation versus nasal continuous positive airway pressure as modes of extubation. Multicentre randomised controlled trial of high against low frequency positive pressure ventilation. Oxford Region Controlled Trial of Artificial Ventilation OCTAVE Study Group. Noninvasive ventilation as a systematic extubation and weaning technique in acute-on-chronic respiratory failure: a prospective, randomized controlled study.
To compare the safety and efficacy of high frequency oscillatory ventilation (HFOV) with conventional mechanical ventilation (CV) for early intervention in adult respiratory distress syndrome (ARDS), a multi-centre randomized trial in four intensive care units was conducted.
                Patients with ARDS were randomized to receive either HFOV or CV. In both treatment arms a priority was given to maintain lung volume while minimizing peak pressures. CV ventilation strategy was aimed at reducing tidal volumes. In the HFOV group, an open lung strategy was used. Respiratory and circulatory parameters were recorded and clinical outcome was determined at 30 days of follow up.
                The study was prematurely stopped. Thirty-seven patients received HFOV and 24 patients CV (average APACHE II score 21 and 20, oxygenation index 25 and 18 and duration of mechanical ventilation prior to randomization 2.1 and 1.5 days, respectively). There were no statistically significant differences in survival without supplemental oxygen or on ventilator, mortality, therapy failure, or crossover. Adjustment by a priori defined baseline characteristics showed an odds ratio of 0.80 (95% CI 0.22-2.97) for survival without oxygen or on ventilator, and an odds ratio for mortality of 1.15 (95% CI 0.43-3.10) for HFOV compared with CV. The response of the oxygenation index (OI) to treatment did not differentiate between survival and death. In the HFOV group the OI response was significantly higher than in the CV group between the first and the second day. A post hoc analysis suggested that there was a relatively better treatment effect of HFOV compared with CV in patients with a higher baseline OI.
                No significant differences were observed, but this trial only had power to detect major differences in survival without oxygen or on ventilator. In patients with ARDS and higher baseline OI, however, there might be a treatment benefit of HFOV over CV. More research is needed to establish the efficacy of HFOV in the treatment of ARDS. We suggest that future studies are designed to allow for informative analysis in patients with higher OI. To compare the hospital course and clinical outcome of preterm infants with respiratory distress syndrome treated with surfactant and managed with high-frequency oscillatory ventilation (HFOV) or conventional mechanical ventilation (CV) as their primary mode of ventilator support.
                A prospective randomized clinical trial.
                Three community-based level III neonatal intensive care units.
                A total of 125 neonates who were 35 weeks or less estimated gestation requiring intubation and assisted ventilation for respiratory distress syndrome with arterial to alveolar oxygen ratio less than .50.
                Patients were randomized to continue CV (61 patients) or be changed to HFOV (64 patients) after exogenous surfactant administration (100 mg/kg). HFOV was used in a strategy to promote lung recruitment and maintain lung volume. Protocol respiratory care guidelines were followed; otherwise routine care was provided by each neonatal intensive care unit.
                No differences were noted in demographic features between the two study groups. The study population birth weight was 1.51 +/- .47 kg (mean +/- SD), gestational age was 30.9 +/- 2.5 weeks, and study entry age was 2 to 3 hours. Patients randomized to HFOV demonstrated the following significant findings compared with CV-treated patients: vasopressor support was less intensive; surfactant redosing was not as frequent; oxygenation improved more rapidly and remained higher during the first 7 days; fewer infants required prolonged supplemental oxygen or ventilator support; treatment failure was reduced; more patients survived without chronic lung disease at 30 days; need for continuous supplemental oxygen at discharge was less; frequency of necrotizing enterocolitis illness was lower; there were fewer abnormal hearing tests; and hospital costs were decreased. No differences were seen between the two study groups in the frequency or severity of patent ductus arteriosus, air leak, retinopathy of prematurity, or intraventricular hemorrhage. Length of hospital stay and survival to discharge were similar for HFOV- and CV-treated infants.
                When used early with a lung recruitment strategy, HFOV after surfactant replacement resulted in clinical outcomes consistent with a reduction in both acute and chronic lung injury. Benefit was evident for preterm infants both less than or equal to 1 kg and more than 1 kg. In addition, early HFOV treatment may have had a more global effect on patient health throughout the hospitalization, resulting in reduced morbidity and decreased health care cost. Few data exist about patient-triggered ventilation techniques in neonatal critical care. Our aim was to compare pressure-limited synchronised intermittent positive pressure (or assist/control) ventilation (sIPPV) in the classical time-cycled (TC-sIPPV) mode against flow-cycled (FC-sIPPV) modality. In this latter, typical sIPPV full respiratory support is provided but both the initiation and the end of inflation are determined by the infant's spontaneous respiratory efforts by using airway flow changes.
                A third-level neonatal intensive care unit.
                Ten preterm babies (<32 weeks' gestation) were randomised to receive 1 h FC-sIPPV followed by 1 h TC-sIPPV or the inverse shift, according to a computer-created randomisation table. Eligible babies had hyaline membrane disease and received 200 mg/kg surfactant at least 6 h before the study period. Respiratory mechanics, ventilatory and vital parameter data were registered real time.
                FC-sIPPV resulted in lower-rate volume ratio, pressure x rate product, mean airway pressure and heart rate; tidal volume and oxygen saturation were higher (all p<0.001). Spontaneous inspiratory time was lower than usually set by the physician and it was directly correlated to birth weight (rho = 0.5, p = 0.001) and gestational age (rho = 0.32, p = 0.001). No differences were noticed in the mechanics and blood gas and vital parameters during the two study phases.
                FC-sIPPV may safely result in a better patient ventilator synchrony. Inspiratory time usually set in neonatal critical care is higher than that decided by the baby during spontaneous effort. This should be considered when establishing time-cycled ventilation. Enhanced airway clearance is thought to result in better-maintained pulmonary function in cystic fibrosis (CF). Postural drainage, percussion, and vibration (PDPV) have been the primary airway clearance technique (ACT) employed in CF for over 40 years. Two new airway clearance modalities are high-frequency chest wall oscillation (HFCWO) and oscillating positive expiratory pressure (OPEP). This pilot study was undertaken to evaluate the efficacy of these techniques during home use, assess patient satisfaction with them as compared to PDPV, and assess the feasibility of performing a definitive comparative trial. The prospective, randomized, multicenter crossover trial was conducted at three urban academic CF Care Centers. Twenty-nine CF patients, 9-39 years of age, participated. Subjects performed 4 weeks each of HFCWO and OPEP following 2-week lead-in/washout periods. Spirometry, lung volumes, National Institutes of Health and Petty Scores, and a satisfaction survey were performed at baseline and after each treatment period. An ACT preference survey was completed at the conclusion of the study. Twenty-four subjects completed both therapies. There were no statistically significant differences between therapies for spirometry, lung volumes, or clinical scores. No significant safety issues arose during the study period. Compliance between therapies was similar. Significant differences among therapies existed in patient satisfaction. Given a choice of therapy, 50% of subjects chose HFCWO, 37% OPEP, and 13% PDPV. This study suggests that HFCWO and OPEP are safe and as effective as patients' routine therapies when used for airway clearance in a home setting. Patient satisfaction and preference differ among ACTs and should be considered when prescribing home therapy. A definitive, multi-center, comparative study evaluating long-term efficacy of these techniques is feasible.
                Copyright 2001 Wiley-Liss, Inc. In patients with acute exacerbations of chronic obstructive pulmonary disease (COPD), noninvasive ventilatory support (NPPV) with bilevel positive airway pressure (BiPAP) may improve clinical and physiological parameters. The present study used a randomized, prospective design to evaluate the possible benefits of NPPV plus standard therapy versus standard therapy alone in patients admitted with acute hypercapnic respiratory failure in a respiratory unit of a tertiary hospital.
                Forty-one patients were included in the study. Of them, 20 were randomly allocated to receive NPPV with a standard mask connected to a BiPAP ventilatory assist device (Respironics Inc, Murrysville, PA) and 21 to standard therapy. Both groups had similar characteristics upon their admission in the hospital.
                The use of noninvasive ventilation significantly reduced the respiratory rates and improved the conscious level within the first 2 h (p < 0.001). There were significant differences in PaCO2 and pH (p < 0.05) at 6 h of treatment. The need for intubation was 5% in the NPPV group vs 14% in the control group. The length of hospital stay was significantly shorter in the NPPV group (7 vs 10 days; p < 0.01). Nasal NPPV was well tolerated and complications were uncommon and mild.
                Early use of noninvasive ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease leads to a more rapid improvement of physiological variables. Moreover, it is possible to apply this treatment in a general respiratory ward. To compare the effectiveness of high-frequency oscillatory ventilation with conventional mechanical ventilation in pediatric patients with respiratory failure.
                Five tertiary care pediatric intensive care units.
                A prospective, randomized, clinical study with crossover.
                Seventy patients with either diffuse alveolar disease and/or airleak syndrome were randomized to receive high-frequency oscillatory ventilation or conventional mechanical ventilation.
                Patients randomized to receive high-frequency oscillatory ventilation were managed, using a strategy that consisted of aggressive increases in mean airway pressure to attain the "ideal" lung volume and to achieve an arterial oxygen saturation of > or = 90%, with an FIO2 of < or = 0.6. Patients who were randomized to receive conventional mechanical ventilation were treated with a strategy that utilized increases in end-expiratory pressure and inspiratory time to increase mean airway pressure and to limit increases in peak inspiratory pressure. Target blood gas values were the same for both groups. Crossover to the alternate ventilator was required if the patient met defined criteria for treatment failure.
                Physiologic data and ventilatory parameters were collected prospectively at predetermined intervals after randomization. Airleak Scores were derived daily, based on the chest radiograph and the patient's clinical condition. In the high-frequency oscillatory ventilation group, the PaO2/PAO2 ratio increased significantly and the oxygenation index (mean airway pressure x FIO2 x 100/PaO2) decreased significantly over time. There were no differences between the groups in duration of mechanical ventilation, frequency of airleak, Airleak Scores, or 30-day survival rates. Significantly fewer patients treated with high-frequency oscillatory ventilation required supplemental oxygenation at 30 days compared with patients managed with conventional ventilation. When ventilatory subgroups were compared, the patients managed with high-frequency oscillation only had significantly better ranked outcomes than patients managed with conventional ventilation only.
                Our results indicate that high-frequency oscillatory ventilation, utilizing an aggressive volume recruitment strategy, results in significant improvement in oxygenation compared with a conventional ventilatory strategy designed to limit increases in peak airway pressures. Furthermore, despite the use of higher mean airway pressures, the optimal lung volume strategy used in this study was associated with a lower frequency of barotrauma, as indicated by requirement for supplemental oxygen at 30 days, and improved outcome compared with conventional mechanical ventilation. To determine whether synchronized nasal intermittent positive pressure ventilation (SNIPPV) would decrease extubation failure compared with nasal continuous positive airway pressure (NCPAP) in preterm infants being ventilated for respiratory distress syndrome (RDS).
                Infants who were </=34 weeks' gestational age and who were ventilated for RDS were randomized to either SNIPPV or NCPAP after extubation. The criteria for extubation were peak inspiratory pressure of </=16 cm H(2)O, positive end expiratory pressure of </=5 cm H(2)O, intermittent mandatory ventilation rate of 15 to 25, and fraction of inspired oxygen </=0.35. Pulmonary function tests (PFT) were obtained before extubation. After extubation, blood gases were monitored for a minimum of 72 hours. Success was defined as remaining in the selected mode of treatment or demonstrating improvement (switching to oxyhood/nasal cannula/room air) by 72 hours.
                Thirty-two (94%) of 34 infants were extubated successfully with the use of SNIPPV versus 18 (60%) of 30 with the use of NCPAP (P <.01). There was no difference in apnea/bradycardia episodes in the 2 groups during the 72-hour study period. Among 55 infants who had PFT, 80% (8 of 10) with dynamic lung compliance of >/=0.5 mL/kg/cm H(2)O and expiratory airway resistance of </=70 cm H(2)O/L/s were extubated successfully. In infants with poor lung function (dynamic lung compliance: <0.5 mL/kg/cm H(2)O; expiratory airway resistance: >70 cm H(2)O/L/s), successful extubation was seen in 93% (27 of 29) in the SNIPPV group and 60% (15 of 25) in the NCPAP group. When weight was controlled for at the time of extubation, the odds of success in the SNIPPV group were 21.1 times higher (95% confidence interval: 3.4, 130.1) than that of the NCPAP group.
                SNIPPV is more effective than NCPAP in weaning infants with RDS from the ventilator. PFT may be useful in predicting successful extubation. A total of 346 infants aged less than 72 hours were randomly allocated to be treated either by high frequency positive pressure ventilation (HFPPV; rate fixed at 60/minute throughout treatment and initial inspiratory:expiratory (I:E) ratio 1:2, increased to 1:1 if necessary) or by low frequency positive pressure ventilation (LFPPV; rate less than or equal to 40/minute and initial I:E ratio usually 1:1, both decreasing during weaning). The main hypotheses were that HFPPV reduces pneumothorax, chronic lung disease and death before discharge in all infants, as well as those with hyaline membrane disease, and that it reduces the incidence of later neurodevelopmental complications in infants of less than 33 weeks' gestation. Among all the infants the rate of pneumothorax was 19% in the HFPPV group and 26% in the LFPPV group (p = 0.13; odds ratio 0.7, 95% confidence intervals (CI) 0.4 to 1.1); there was no difference in mortality or the incidence of chronic lung disease. In infants of less than 33 weeks' gestation there were no differences in adverse neurodevelopmental outcomes. Among the subgroup of 237 infants with hyaline membrane disease, median fractional inspired oxygen at the time of entry to the trial was 0.6 in the HFPPV group and 0.7 in the LFPPV group, indicating that many had moderately severe disease. In patients with hyaline membrane disease HFPPV was associated with a lower rate of pneumothorax (18% in the HFPPV group compared with 33% in the LFPPV group, p = 0.013, odds ratio 0.5, 95% CI 0.3 to 0.8, with no differences in mortality, or in duration of intubation or supplementary oxygen in survivors. As used in this study, HFPPV was the preferred ventilator regimen for infants with hyaline membrane disease. Prolonged duration of endotracheal mechanical ventilation (ETMV) is associated with an increased morbidity and mortality in intensive care unit (ICU) patients. The aim of this study was to assess the usefulness of noninvasive ventilation (NIV) as a systematic extubation and weaning technique to reduce the duration of ETMV in acute-on-chronic respiratory failure (ACRF). Among 53 consecutively intubated patients admitted for ACRF, we conducted a prospective, randomized controlled trial of weaning in 33 patients who failed a 2-h T-piece weaning trial (2 h-WT) although they met simple criteria for weaning. Conventional invasive pressure support ventilation (IPSV) was used as the control weaning technique in 16 patients (IPSV group), and NIV was applied immediately after extubation in 17 patients (NIV group). The two weaning groups were similar for type of chronic respiratory failure (CRF), pulmonary function data, age, Simplified Acute Physiology Score (SAPS II), and severity of ACRF on admission. The characteristics of the two groups were also similar at randomization. In the IPSV group, 12 of 16 patients (75%) were successfully weaned and extubated, versus 13 of 17 (76.5%) in the NIV group (p = NS). NIV like IPSV significantly and similarly improved gas exchange in relation to that achieved during 2 h-WT (p < 0.05). The duration of ETMV was significantly shorter in the NIV (4.56 +/- 1.85 d) than in the IPSV group (7.69 +/- 3.79 d) (p = 0. 004). NIV also reduced the mean period of daily ventilatory support, but increased the total duration of ventilatory support related to weaning (3.46 +/- 1.42 d, versus 11.54 +/- 5.24 d with NIV; p = 0. 0001). Most patients in the IPSV group developed complications related to ETMV and/or the weaning process, but the difference was not significant (nine of 16 versus six of 17). The durations of ICU and hospital stays and the 3-mo survival were similar in the two groups. In conclusion, NIV permits earlier removal of the endotracheal tube than with conventional IPSV, and reduces the duration of daily ventilatory support without increasing the risk of weaning failures. NIV should be considered as a new and useful systematic approach to weaning in patients with ACRF who are difficult to wean.
Compared to conventional ventilation, benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in air leak and a shorter duration of ventilation, respectively. In none of the trials was complex respiratory monitoring undertaken and thus it is not possible to conclude that the mechanism of producing those benefits is by provocation of synchronized ventilation. Further trials are needed to determine whether synchronized ventilation is associated with other benefits, but optimisation of trigger and ventilator design with respect to respiratory diagnosis is encouraged before embarking on further trials. It is essential newer forms of triggered ventilation are tested in adequately powered randomised trials with long-term outcomes before they are incorporated into routine clinical practice.