High-frequency Oscillatory Ventilation Treatment Research Articles

The effect of high-frequency oscillatory ventilator combined with pulmonary surfactant in the treatment of neonatal respiratory distress syndrome.

Objective:To investigate the efficacy of high-frequency oscillatory ventilation (HFOV) combined with pulmonary surfactant (PS) in the treatment of neonatal respiratory distress syndrome (NRDS).Methods:This study is a retrospective clinical study. Seventy-two NRDS neonates were selected as the subjects from November 2019 to November 2020, and divided into observation group (40 cases, HFOV treatment) and control group (32 cases, conventional mechanical ventilation treatment). All cases were treated with PS and comprehensive treatment. The therapeutic effect, arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), Percentage of inhaled oxygen concentration (FiO2), mean arterialpressure, oxygenation index (OI), and complications were compared in the 2 groups.Results:The total effective rate of the observation group was 90.0%, significantly higher than that of the control group. After treatment, the observation group has higher PaO2 levels and lower levels of PaCO2, mean arterial pressure, FiO2, and OI than the control group. There was no significant difference in the incidence of complications between the 2 groups.Conclusion:HFOV combined with PS has a significant effect on NRDS, which can improve the arterial blood gas index without increasing the incidence of complications.

Association between the IL-6 polymorphisms and coal workers’ pneumoconiosis in a Chinese Hui population

ObjectiveTo determine whether polymorphisms in IL-6 and IL-12 contribute to the etiology of coal workers’ pneumoconiosis (CWP) in a Chinese Hui population, and to evaluate the efficacy and safety of high frequency oscillatory ventilation (HFOV) in the treatment of CWP.IntroductionGenes and the environments interplay in the development of CWP, and the association between the potential functional polymorphisms in many genes and CWP have been reported.MethodsWe genotyped the IL-6-634C/G (rs1800796) and IL-12B-1188A/C (rs3212227) polymorphisms in a case-control study including 160 CWP patients and 150 dust-exposed control subjects of Chinese Hui population, and analyzed the associations between these genetic variants and CWP risk. We also evaluated the efficacy and safety of HFOV for whole lung lavage (WLL) in the treatment of CWP.ResultsCarrying the C allele of IL-6-634C/G (rs1800796) was associated with decreased risk of CWP ( p < 0.05). No significant differences in allele or genotype frequencies of IL-12B-1188A/C was found between the CWP cases and control subjects ( p > 0.05). Compared with CWP patients with routine WLL, CWP patients received HFOV showed better pulmonary functions. HFOV treatment also yield a significant higher efficient rate (97.50%) than WLL treatment (81.25%, p = 0.001). CWP patients receiving HFOV and WLL treatment both showed significantly increased serum contents of Clara cell protein 16 (CC16) and superoxide dismutase (SOD), and decreased serum contents of serum malonaldehyde (MDA). While the increasing of CC16 and SOD, and decreasing of MDA in patients receiving HFOV was more noticeable than patients receiving WLL.ConclusionsTaking together, the −634C/G polymorphisms in IL-6 play a role in the etiology of CWP. HFOV, when applied in CWP patients, significant improves their pulmonary functions.

Effect of postoperative administration of inhaled nitric oxide combined with high-frequency oscillatory ventilation in infants with acute hypoxemic respiratory failure and pulmonary hypertension after congenital heart surgery: A retrospective cohort study.

To evaluate the effect of inhaled nitric oxide (iNO) combined with high-frequency oscillatory ventilation (HFOV) in the treatment of infants with acute hypoxemic respiratory failure (AHRF) and pulmonary hypertension (PH) after congenital heart surgery. A retrospective study was conducted on 63 infants with AHRF and PH after congenital heart surgery in our cardiac intensive care unit (CICU) from January 2020 to March 2021. A total of 24 infants in the A group were treated with HFOV combined with iNO, and 39 infants in the B group were treated with HFOV. Relevant clinical data were collected. Comparing the two groups, the improvement of the oxygenation index, PaO2 and PaO2 /FiO2 was more obvious for patients in the A group than for those in the B group after intervention (p < .05). Reexamination on the third day after the initiation of HFOV treatment indicated that the systolic pulmonary artery pressure in the A group was significantly lower than that in the B group (p < .05). In addition, the duration of mechanical ventilation and the length of CICU stay in the A group were shorter than those in the B group (p < .05). However, complications between the two groups were not statistically significant. No important adverse effects arose. For infants with AHRF and PH after congenital heart surgery, iNO combined with HFOV is superior to HFOV alone to improve oxygenation, decrease pulmonary pressure, and shorten the duration of mechanical ventilation and the length of CICU stay, with no adverse effects.

Therapeutic effects and outcomes of rescue high-frequency oscillatory ventilation for premature infants with severe refractory respiratory failure

Despite wide application of high frequency oscillatory ventilation (HFOV) in neonates with respiratory distress, little has been reported about its rescue use in preterm infants. We aimed to evaluate the therapeutic effects of HFOV in preterm neonates with refractory respiratory failure and investigate the independent risk factors of in-hospital mortality. We retrospectively analyzed data collected prospectively (January 2011–December 2018) in four neonatal intensive care units of two tertiary-level medical centers in Taiwan. All premature infants (gestational age 24–34 weeks) receiving HFOV as rescue therapy for refractory respiratory failure were included. A total of 668 preterm neonates with refractory respiratory failure were enrolled. The median (IQR) gestational age and birth weight were 27.3 (25.3–31.0) weeks and 915.0 (710.0–1380.0) g, respectively. Pre-HFOV use of cardiac inotropic agents and inhaled nitric oxide were 70.5% and 23.4%, respectively. The oxygenation index (OI), FiO2, and AaDO2 were markedly increased after HFOV initiation (all p < 0.001), and can be decreased within 24–48 h (all p < 0.001) after use of HFOV. 375 (56.1%) patients had a good response to HFOV within 3 days. The final in-hospital mortality rate was 34.7%. No association was found between specific primary pulmonary disease and survival in multivariate analysis. We found preterm neonates with gestational age < 28 weeks, occurrences of sepsis, severe hypotension, multiple organ dysfunctions, initial higher severity of respiratory failure and response to HFOV within the first 72 h were independently associated with final in-hospital mortality. The mortality rate of preterm neonates with severe respiratory failure remains high after rescue HFOV treatment. Aggressive therapeutic interventions to treat sepsis and prevent organ dysfunctions are the suggested strategies to optimize outcomes.

An observational, prospective, multicenter study on rescue high-frequency oscillatory ventilation in neonates failing with conventional ventilation.

BackgroundTo achieve gas exchange goals and mitigate lung injury, infants who fail with conventional ventilation (CV) are generally switched to high-frequency oscillatory ventilation (HFOV). Although preferred in many neonatal intensive care units (NICUs), research on this type of rescue HFOV has not been reported recently.MethodsAn online registry database for a multicenter, prospective study was set to evaluate factors affecting the response of newborn infants to rescue HFOV treatment. The study population consisted of 372 infants with CV failure after at least 4 hours of treatment in 23 participating NICUs. Patients were grouped according to their final outcome as survived (Group S) or as died or received extracorporeal membrane oxygenation (ECMO) (Group D/E). Patients’ demographic characteristics and underlying diseases in addition to their ventilator settings, arterial blood gas (ABG) analysis results at 0, 1, 4, and 24 hours, type of device, ventilation duration, and complications were compared between groups.ResultsHFOV as rescue treatment was successful in 58.1% of patients. Demographic and treatment parameters were not different between groups, except that infants in Group D/E had lower birthweight (BW) (1655 ± 1091 vs. 1858 ± 1027 g, p = 0.006), a higher initial FiO2 setting (83% vs. 72%, p < 0.001), and a higher rate of nitric oxide exposure (21.8% vs. 11.1%, p = 0.004) in comparison to infants who survived (Group S). The initial cut-offs for a successful response on ABG were defined as pH >7.065 (OR: 19.74, 95% CI 4.83–80.6, p < 0.001), HCO3 >16.35 mmol/L (OR: 1.06, 95% CI 1.01–1.1, p = 0.006), and lactate level <3.75 mmol/L (OR: 1.09%95 CI 1.01–1.16, p = 0.006). Rescue HFOV duration was associated with retinopathy of prematurity (p = 0.005) and moderate or severe chronic lung disease (p < 0.001), but not with patent ductus arteriosus or intraventricular hemorrhage, in survivors (p > 0.05).ConclusionRescue HFOV as defined for this population was successful in more than half of the patients with CV failure. Although the response was not associated with gestational age, underlying disease, device used, or initial MV settings, it seemed to be more effective in patients with higher BW and those not requiring nitric oxide. Initial pH, HCO3, and lactate levels on ABG may be used as predictors of a response to rescue HFOV.

Clinical Study of High Frequency Oscillatory Ventilation on Neonatal Respiratory Distress Syndrome

To investigate the clinical effect of high frequency oscillatory ventilation (HFOV) in neonatal respiratory distress syndrome (NRDS). Forty-six children with NRDS who were treated in Neonatal Intensive Care Unit (NICU) from January 2015 to December 2016 were selected as study subjects, 34 in study group (HFOV) and 12 in control group (SIMV), both groups were given basic and PS treatment, blood gas analysis and clinical treatment before and after treatment were compared indicators. Compared with SIMV group, HFOV group had faster blood gas analysis and treatment and fewer complications. HFOV and PS combined treatment of neonatal respiratory distress syndrome obvious effect, high safety, worthy of clinical promotion and use.

Effect of high frequency oscillatory ventilation on EVLW and lung capillary permeability of piglets with acute respiratory distress syndrome caused by pulmonary and extrapulmonary insults.

The effect of high frequency oscillatory ventilation (HFOV) at early stage on hemodynamic parameters, extravascular lung water (EVLW), lung capillary permeability, CC16 and sICAM-1 in piglets with pulmonary or extrapulmonary acute respiratory distress syndrome (ARDS) was explored. Central vein pressure (CVP) and pulse indicator continuous cardiac output (PiCCO) were monitored in 12 anesthetized and intubated healthy piglets. Pulmonary ARDS (ARDSp) and extrapulmonary ARDS (ARDSexp) models were respectively established by lung lavage of saline solution and intravenous injection of oleic acid. Then the piglets received HFOV for 4 h. EVLW index (EVLWI), EVLW/intratroracic blood volume (ITBV) and pulmonary vascular permeability index (PVPI) were measured before and after modeling (T0 and T1), and T2 (1 h), T3 (2 h), T4 (3 h) and T5 (4 h) after HFOV. CC16 and sICAM-1 were also detected at T1 and T5. Results showed at T1, T3, T4 and T5, EVLWI was increased more significantly in ARDSp group than in ARDSexp group (P<0.05). The EVLWI in ARDSp group was increased at T1 (P=0.008), and sustained continuously within 2 h (P=0.679, P=0.216), but decreased at T4 (P=0.007) and T5 (P=0.037). The EVLWI in ARDSexp group was also increased at T1 (P=0.003), but significantly decreased at T3 (P=0.002) and T4 (P=0.019). PVPI was increased after modeling in both two groups (P=0.004, P=0.012), but there was no significant change within 4 h (T5) under HFOV in ARDSp group, while PVPI showed the increasing trends at first, then decreased in ARDSexp group after HFOV. The changes of EVLW/ITBV were similar to those of PVPI. No significant differences were found in ΔEVLWI (P=0.13), ΔPVPI (P=0.28) and ΔEVLW/ITBV between the two groups (P=0.63). The significant decreases in both CC16 and sICAM-1 were found in both two groups 4 h after HFOV, but there was no significant difference between the two groups. It was concluded that EVLWI and lung capillary permeability were markedly increased in ARDSp and ARDSexp groups. EVLW could be decreased 4 h after the HFOV treatment. HFOV, EVLW/ITBV and PVPI were increased slightly at first, and then decreased in ARDSexp group, while in ARDSp group no significant difference was found after modeling. No significant differences were found in the decreases in EVLW and lung capillary permeability 4 h after HFOV.

High-frequency oscillatory ventilation in children with hematologic neoplasms and other causes induced acute hypoxic respiratory failure

Objective To evaluate the significance of high-frequency oscillatory ventilation (HFOV) used in acute hypoxic respiratory failure (AHRF) children, failing to conventional ventilation. Methods This was a retrospective study of AHRF children ventilated by HFOV from January 2011 to September, 2013. All patients were initially treated by conventional mechanical ventilation (CMV), and changed to be treated by HFOV if the patient met to one of the following criteria after the CMV parameters of PIP>30 mmH2O (1 cmH2O＝0.098 kPa) or PEEP>10 cmH2O with FiO2100%: (1) SpO2 80 mmHg); (3) serious air leakage (mediastinal emphysema or pneumothorax). The following parameters were recorded: patient′s gender, age, living PICU time, CMV ventilation time, HFOV ventilation time. We reviewed ventilation parameter settings (MAP, ΔP, F, FiO2), oxygenation index (PaO2/FiO2, OI), arterial blood gas, heart rate, blood pressure at different time points including late CMV (H0), 2 h after HFOV (H2), 6 h after HFOV (H6), 12 h after HFOV (H12), 24 h after HFOV (H24) and 48 h after HFOV (H48), respectively. Various indexes at different time points were compared between survival group and death group, oncology group and no-oncology group. Results PaO2 at H2 compared with H0 had significant improvement[76.9 (61.9~128.0) mmHg vs 50.1 (49.5~68.0) mmHg, P＝0.006]。PaO2/FiO2 at H2, H48 had significant improvement compared with those at H0, H24[94.9 (66.8~138.9) mmHg vs 68.0 (49.5~86.8) mmHg, P＝0.039; 135.0 (77.6~240.0) mmHg vs 90.7 (54.6~161.7) mmHg, P＝0.023)]. All children′s systolic pressure, diastolic blood pressure, heart rate at various time points had no difference (P>0.05). Compared to death group (n＝14), PaO2/FiO2, OI at H6, H12, H24, H48 in survival group (n＝9) had significant improvement (P<0.05). Compared to oncology group (n＝10), OI at H2, H6 in no-oncology group (n＝10) had significant improvement [(19.2 (13.9~26.6) vs 33.8 (19.7~48.3), P＝0.049; 16.0 (8.4~27.1) vs 28.9 (20.9~38.9), P＝0.027)], and mean airway pressure between two groups at H2, H6, H12 had significant improvement (P<0.05). Mortality had no significant differcence between two groups (4/10 vs 10/13, P＝0.086). Conclusion HFOV used in children with AHRF which had failed with CMV ventilation can improve the patient′s PaO2 and OI. Heart rate and blood pressure are stable during HFOV treatment. Oncology group patients needed higher initial MAP to improve oxygenation than no-oncology group patients when changed to HFOV treatment, but the mortality showed no difference between two groups. Key words: High-frequency oscillatory ventilation; Acute hypoxemic respiratory failure; Acute respiratory distress syndrome; Children

Adapted ECMO criteria for newborns with persistent pulmonary hypertension after inhaled nitric oxide and/or high-frequency oscillatory ventilation

Early prediction of extracorporeal membrane oxygenation (ECMO) requirement in term newborns with persistent pulmonary hypertension (PPHN), partially responding to inhaled nitric oxide (iNO) and/or high-frequency oscillatory ventilation (HFOV), based on oxygenation parameters. This was a retrospective cohort study in 53 partial responders from among 133 term newborns with PPHN born between 2002 and 2007. Alveolar-to-arterial oxygen gradient (AaDO₂) values were determined in these 53 partial responders during the initial 72 h of iNO and/or HFOV treatment and compared between newborns who ultimately did (n = 11) and did not (n = 42) need ECMO. Over 72 h, partial responders not requiring ECMO showed a more profound AaDO₂ decrease than those who needed ECMO (median decline 242.5 mmHg, IQR 144 to 353 mmHg, vs. 35 mmHg, IQR -15 to 123 mmHg; p = 0.0007). A decline of <123 mmHg over 72 h predicted the need for ECMO (sensitivity 82 %, specificity 79 %). At 72 h, AaDO₂ was significantly lower in partial responders without the need for ECMO than in those who did need ECMO (median 369 mmHg, IQR 258 to 478 mmHg, vs. 570 mmHg IQR 455 to 590 mmHg; p = 0.0008). An AaDO₂ >561 mmHg at 72 h predicted the need for ECMO (sensitivity 64 %, specificity 95 %, positive predictive value 78 %). In term newborns with PPHN partially responding to iNO and/or HFOV, oxygenation-based prediction of the need for ECMO appears to be possible after 72 h. ECMO centers are encouraged to develop their own prediction model in order to prevent both lung damage and unnecessary ECMO runs.

Early application of high frequency oscillatory ventilation in ‘H1N1 influenza’ related ARDS is associated with better outcome: a retrospective study

Dear Editor, High frequency oscillatory ventilation (HFOV) is an accepted therapy for refractory hypoxemia in acute respiratory distress syndrome (ARDS). There is a paucity of data for use of HFOV for 2009 H1N1 influenza ARDS and whether early application of HFOV decreases mortality in this subgroup of patients with severe ARDS. We performed a retrospective analysis of 19 patients who received HFOV as a rescue therapy for 2009 H1N1 influenza with severe ARDS to study the outcome predictors. Deenanath Mangeshkar Hospital ethics committee has approved use of HFOV as a rescue therapy in severe ARDS and consent was obtained from next of kin. Inclusion criteria were the presence of severe ARDS (PaO2/FiO2 100) due to H1N1 influenza virus infection, the application of a maximal support of conventional mechanical ventilation (PEEP equal or greater than 12 cm H2O), and the use of HFOV as a rescue therapy. Patients who received HFOV treatment for less than 24 h were excluded from the analysis. Out of the 19 patients studied, 10 survived (52 %). Patients were divided into survivors and non-survivors Demographic variables, baseline gas exchange and ventilation variables were comparable. Average age and APACHE II score were 30.21 ± 9.60 years 13.25 ± 1.90, respectively. Average tidal volume and plateau pressure on conventional ventilation prior to initiation of HFOV were 6.12 ± 1.26 ml/kg of predicted body weight and 27.21 ± 3.85 cm H2O, respectively. In the whole cohort there was a significant improvement in PaO2/FiO2 at 24 h, after initiation of HFOV (77.89 ± 32.50 vs. 121.78 ± 37.94, p = 0.005). Earlier application of HFOV was the only significant independent predictor of survival (p = 0.045) on multivariate logistic regression analysis. Survival odds ratio was 7.05 (95 % CI, 1.04–47.78) for every day of reduced conventional ventilation. Cox regression analysis of survival rates adjusted for APACHE II score, oxygenation index and time from symptom onset to hospital contact indicated a decrease in survival with increasing duration of conventional ventilation (Fig. 1, Table 1). Our findings are in general agreement with the literature on ARDS in adults. Terragni et al. [1] has shown that even with a lung protective strategy, ventilator induced lung injury is possible. Matthias David et al., had suggested that, an increased conventional ventilation period of more then 3 days prior to HFOV was associated with higher mortality [2]. A recent meta-analysis had reaffirmed this suggestion [3]. However, Casper Bollen et al, [4] had suggested that prolonged conventional ventilation prior to HFOV is not associated with higher mortality. Patients in this case series, randomized to the HFOV group had received conventional ventilation at higher tidal volumes (9.30 ± 2.20 ml/kg of predicted body weight), prior to initiation of HFOV. Limiting the duration of volume controlled ventilation before HFOV may confer a benefit by pre-empting ventilator induced lung injury in these patients. A limitation of our case series is a small sample size. However, it may provide useful insight into management of severe ARDS related to

Adapted Ecmo Entry Criteria for Newborns with Persistent Pulmonary Hypertension (PPHN) Following Treatment with Inhaled Nitric Oxide (INO) and/or High-Frequency Oscillatory Ventilation (HFOV)

Background and Aim: ECMO entry criteria were developed before introduction of iNO and/or HFOV as conservative treatment in newborns with PPHN. Its use reduces ECMO need in good responders. In partial responders it will prolong the conservative treatment and delay starting of ECMO, which may induce lung damage. The aim of this study is to identify AaDO2 values in early stage which will predict the newborns, who will fail treatment with iNO and/or HFOV and ECMO is ultimately needed. Methods: In a retrospective study (2002-2007) 134 term newborns with PPHN were included. In 57 partial responders, we determined the differences in the decline of AaDO2 during 72h of iNO and/or HFOV treatment and in the value of AaDO2 after these 72h between newborns that ultimately did (n=11) and did not (n=46) need ECMO. Results: After 72h, partial responders not requiring ECMO showed a more profound AaDO2 decrease compared to those who ultimately needed ECMO (median decline 259 (IQR 145-357) vs. 35 (IQR -15-123) mmHg; p=0.0004). A decline < 123 mmHg in 72h predicted ECMO need (sensitivity 82%, specificity 80%). At 72h, AaDO2 was significantly lower in partial responders without ECMO need (335 (IQR 246-470) vs. 570 (IQR 455-590) mmHg; p=0.0006). An AaDO2 > 561 mmHg at 72h predicted ECMO need (sensitivity 64%, specificity 95%). Conclusions: Term newborns with PPHN showing an AaDO2 > 561 mmHg or a decline in AaDO2 < 123 mmHg (20%) compared to baseline after 72h of iNO and/or HFOV treatment should be considered candidates for ECMO.

Observation on High-frequency oscillatory ventilation in the treatment of severe neonatal respiratory distress syndrome

Objective To evaluate the effectives of high-frequency oscillatory ventilation (HFOV)in the treatment of severe NRDS.Methods The severe NRDS who failed to response to conventional mechanical ventilation (CMV) were changed to HFOV treatment.Ventilator parameters and blood gas analysis were compared before and after treatment.Results Among thirty patients,19 cases were significantly improved and 11 cases were failed,the success rate was 63％.Nineteen patients with HFOV,the main ventilator parameters and blood gas results such as FiO2 ( 0 h:0.87 ± 0.09 vs 3 h:0.67 ± 0.10,6 h:0.54 ±0.08,12h:0.44 ±0.08),MAP[0 h:(14.47 ±1.17) mbar vs 3 h:(13.79 ± 1.03) mbar,6 h:(13.26 ±1.05) mbar,12 h:( 12.37 ±0.83) mbar],f[0 h:(7.26 ±0.56) Hz vs 3 h:(7.89 ±0.57) Hz,6 h:(8.42±0.51 ) Hz,12 h:(9.26 ±0.45) Hz] and PaCO2 [0 h:(9.69 ±0.86) kPa vs 3 h:(6.00 ±0.55) kPa,6 h:(5.62 ± 1.03)kPa,12 h:(5.47 ±0.55)kPa] were decreased while pH(0 h:7.21 ±0.06 vs 3 h:7.35 ±0.07,6 h:7.39 ±0.07,12 h:7.40 ±0.06) and PaO2[0 h:(5.46 ±0.82)kPa vs 3 h:(7.92 ± 1.13)kPa,6 h:(9.25 ± 0.99)kPa,12 h:(9.20 ± 0.96)kPa] were significantly increased compared with before treatment ( P ＜ 0.05).Conclusions The patients of severe NRDS who failed to response to CMV were treated with HFOV,some patients received a significant effect with HFOV treatment. Key words: High-frequency ventilation/MT; Respiratory distress syndrome, newborn/TH

Decreased use of neonatal extracorporeal membrane oxygenation (ECMO): how new treatment modalities have affected ECMO utilization.

Over the last decade, several new therapies, including high-frequency oscillatory ventilation (HFOV), exogenous surfactant therapy, and inhaled nitric oxide (iNO), have become available for the treatment of neonatal hypoxemic respiratory failure. The purpose of this retrospective study was to ascertain to what extent these modalities have impacted the use of neonatal extracorporeal membrane oxygenation (ECMO) at our institution. Patients from 2 time periods were evaluated: May 1, 1993 to November 1, 1994 (group 1) and May 1, 1996 to November 1, 1997 (group 2). During the first time period (group 1), HFOV was not consistently used; beractant (Survanta) use for meconium aspiration syndrome (MAS), persistent pulmonary hypertension of the newborn (PPHN), and pneumonia was under investigation; and iNO was not yet available. During the second time period (group 2), HFOV and beractant treatment were considered to be standard therapies, and iNO was available to patients with oxygenation index (OI) >/=25 x 2 at least 30 minutes apart, or on compassionate use basis. Patients were included in the data collection if they met the following entry criteria: 1) OI >15 x 1 within the first 72 hours of admission; 2) EGA >/=35 weeks; 3) diagnosis of MAS, PPHN or sepsis/pneumonia; 4) <5 days of age on admission; and 5) no congenital heart disease, diaphragmatic hernia, or lethal congenital anomaly. Of the 49 patient in group 1, 21 (42.8%) required ECMO therapy. Of these ECMO patients, 14 (66.6%) had received diagnoses of MAS or PPHN. Only 3 of the patients that went on to ECMO received beractant before the initiation of bypass (14.3%). All ECMO patients in group 1 would have met criteria for iNO had it been available. Of all patients in group 1, 18 (36.7%) were treated with HFOV, and 13 (26.5%) received beractant. Of the 47 patients in group 2, only 13 (27.7%) required ECMO therapy (compared with group 1). Of these ECMO patients, only 5 (38.5%) had diagnoses of MAS or PPHN, with the majority of patients (61.5%) requiring ECMO for sepsis/pneumonia, with significant cardiovascular compromise. Only 5 of these ECMO patients, all outborn, did not receive iNO before cannulation because of the severity of their clinical status on admission. Of all patients in group 2, 41 (87.2%) were treated with HFOV (compared with group 1), 42 (89.3%) received beractant (compared with group 1), and 18 (44.7%) received iNO. The results indicate that ECMO was used less frequently when HFOV, beractant and iNO was more commonly used. The differences in treatment modalities used and subsequent use of ECMO were statistically significant. We speculate that, in this patient population, the diagnostic composition of neonatal ECMO patients has changed over time.

Exhaled Nitric Oxide Increases During High Frequency Oscillatory Ventilation in Rabbits

This study compared the effects of high frequency oscillatory ventilation (HFOV) and intermittent mandatory ventilation (IMV) on the homeostasis of nitric oxide (NO) in the lower respiratory tract of healthy rabbits. The mechanisms underlying a putative stretch response of NO formation in the airways were further elucidated. Male New Zealand White rabbits were anaesthetized, tracheotomized and ventilated with IMV or HFOV in random order. Total NO excretion increased from 9.6 +/- 0.8 nl min-1 (mean +/- S.E.M.) during IMV to 22.6 +/- 2.7 nl min-1 during HFOV (P < 0.001). This increase was not explained by changes of functional residual capacity ([Delta]FRC). A similar increase in NO excretion during HFOV was seen in isolated buffer-perfused lungs under constant circulatory conditions (P < 0. 05, n = 4). Intratracheal mean CO2 and NO concentrations, measured at 2.5, 5, 7.5 and 10 cm below tracheostomy, increased significantly with increasing distance into the lung during both IMV and HFOV (P < 0.001 for each comparison). At every intratracheal location of the sampling catheter, particularly low in the airways, both CO2 and NO concentrations were significantly higher during HFOV than during IMV (P < 0.01 for each comparison). We conclude that HFOV increases pulmonary NO production in healthy rabbits. Increased stretch activation of the respiratory system during HFOV is suggested as a possible underlying mechanism. The increase in mean airway NO concentrations may have biological effects in the respiratory tract. Whether it can account for some of the benefits of HFOV treatment needs to be considered.

The Provo Multicenter Early High-frequency Oscillatory Ventilation Trial: Improved Pulmonary and Clinical Outcome in Respiratory Distress Syndrome

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.

High-Frequency Oscillatory Ventilation and Extracorporeal Membrane Oxygenation for the Treatment of Acute Neonatal Respiratory Failure

Forty-six (92%) outborn and four (8%) inborn term or near-term neonates were admitted for extracorporeal membrane oxygenation (ECMO) treatment to a neonatal intensive care unit between July 1, 1985, and November 1, 1987. All infants had PAO2-PaO2 greater than or equal to 600 mm Hg in spite of aggressive conventional ventilatory and pharmacologic therapy. All patients were offered rescue treatment with high-frequency oscillatory ventilation (HFOV), and only if there was no improvement in PAO2-PaO2 with HFOV were infants treated using ECMO. Four patients died before receiving an adequate trial of HFOV and before emergency ECMO support could be initiated; 21 patients, all of whom survived to hospital discharge, responded to HFOV; 25 patients ultimately required ECMO therapy for cardiopulmonary support, with 22 (88%) surviving to discharge. Neonates responding to HFOV were of slightly younger gestational age (38 +/- 2 weeks vs 40 +/- 2 weeks, mean +/- SD; P less than .001) and more frequently had clinical evidence of pneumonia (11 of 21 vs 2 of 25; P less than .002). There was no statistically significant difference in outcome with respect to the number of ventilator days, hospital days, or survival between patients responding to HFOV and patients who required ECMO. Morbidity was increased in ECMO patients, with bleeding abnormalities, seizures, and renal failure occurring more frequently than in HFOV-treated infants. Overall, 92% (46 of 50) of the patients were treated with a staged protocol using HFOV before ECMO. A total of 46% (21 of 46) responded to HFOV treatment alone and did not require ECMO therapy.(ABSTRACT TRUNCATED AT 250 WORDS)