High-frequency Oscillation Group Research Articles

Effect of high-frequency oscillation on reduction of atelectasis in perioperative patients: a prospective randomized controlled study

Background Atelectasis affects approximately 90% of anaesthetized patients, with laparoscopic surgery and pneumoperitoneum reported to exacerbate this condition. High-frequency oscillation therapy applies continuous positive pressure pulses to oscillate the airway, creating a pressure difference in small airways obstructed by secretions. This process helps reduce peak airway pressure, open small airways, and decrease atelectasis incidence, while also facilitating respiratory tract clearance. This study examines the efficacy of high-frequency oscillation on reduction of atelectasis in laparoscopic cholecystectomy (LC) patients under general anaesthesia, evaluated using lung ultrasound. Methods Sixty-four patients undergoing laparoscopic cholecystectomy were randomly divided into a control group and a high-frequency oscillation (HFO) group. Both groups underwent total intravenous anaesthesia under invasive arterial monitoring. The HFO group received a 10-minute continuous high-frequency oscillation therapy during surgery, while the control group received no intervention. Lung ultrasound evaluations were performed three times: five minutes post-intubation (T1), at the end of the surgery (T2), and before leaving the Post-Anaesthesia Care Unit (PACU; T3). Blood gas analysis was performed twice: prior to induction with no oxygen supply and before PACU discharge (oxygen supply off). Results The HFO group displayed a significantly lower incidence of atelectasis at T3 (57.5% vs. 90.3%, OR 6.88, 95%CI (1.74 to 27.24)) compared to the control group. Moreover, the HFO group’s PaO2 levels remained consistent with baseline levels before PACU discharge, unlike the control group. Although there was no significant difference in LUS scores between the groups at T1 (8.56 ± 0.15 vs. 8.19 ± 0.18, p = 0.1090), the HFO group had considerably lower scores at T2 (13.41 ± 0.17 vs.7.59 ± 0.17, p < 0.01) and T3 (13.72 ± 0.14 vs.7.25 ± 0.21, p < 0.01). Conclusion Our study indicates that high-frequency oscillation effectively reduces atelectasis in patients undergoing laparoscopic cholecystectomy. Additionally, it can mitigate the decline in oxygen partial pressure associated with atelectasis.

Longitudinal changes in lung function in very prematurely born young people receiving high-frequency oscillation or conventional ventilation from birth.

ObjectiveTo examine changes in lung function over time in extremely prematurely born adolescents.Working HypothesisChanges in lung function during adolescence would vary by ventilation mode immediately after birth.Study DesignLongitudinal follow‐up study.Patient Subject SelectionParticipants from the United Kingdom Oscillation Study who were randomized at birth to high‐frequency oscillation (HFO) or conventional ventilation (CV) were assessed at 11–14 years (n = 319) and at 16–19 years (n = 159).MethodologyForced expiratory flow (FEF), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and lung volumes including functional residual capacity (FRC) were reported as z‐scores. The diffusion capacity of the lungs for carbon monoxide (DLCO) was measured. Lung function trajectories were compared by mode of ventilation using mixed models. Changes in z‐scores were scaled to 5‐year average follow‐up.ResultsThere were significant changes in the mean FEF75, FEF50, FEF25, FEV1, FVC, and DLCO z‐scores within the CV and HFO cohorts, but no significant differences in the changes between the two groups. The mean FRC z‐score increased in both groups, with an average change of greater than one z‐score. The mean FEV1/FVC z‐score increased significantly in the CV group, but not in the HFO group (difference in slopes: p = 0.02). Across the population, deterioration in lung function was associated with male sex, white ethnicity, lower gestational age at birth, postnatal corticosteroids, oxygen dependency at 36 weeks postmenstrual age, and lower birth weight, but not ventilation mode.ConclusionsThere was little evidence that the mode of ventilation affected changes in lung function over time.

High frequency oscillatory ventilation versus conventional mechanical ventilation in pediatric acute respiratory distress syndrome: A randomized controlled study.

El-Nawawy A, Moustafa A, Heshmat H, Abouahmed A. High frequency oscillatory ventilation versus conventional mechanical ventilation in pediatric acute respiratory distress syndrome: A randomized controlled study. Turk J Pediatr 2017; 59: 130-143. The aim of this prospective randomized study is to compare the outcomes of the early use of either high frequency oscillation (HFO) or conventional mechanical ventilation (CMV) in patients with pediatric acute respiratory distress syndrome (PARDS). We allocated two hundred PARDS patients over 5 years in 1:1 ratio to either mode. The HFO group showed a significantly higher median partial arterial oxygen pressure to fraction of inspired oxygen (PaO2/FiO2) values after 24 hours of enrollment (p=0.011), higher oxygenation index (OI) decrease percent (p=0.004) and lower cross-over rates (p < 0.001), whereas no differences in 30-day mortality, length of stay (LOS) or ventilation days (p=0.77, p=0.28, p=0.65 respectively). The second day values (after 24 hours) of both OI and PaO < sub > 2 < /sub > /FiO < sub > 2 < /sub > were found to be more significant discriminators for mortality when compared to the baseline values (cutoff values > 8.5, ≤139 respectively). PARDS patients with baseline OI > 16 had a better chance of survival if initially ventilated with the HFO (p=0.004). Although the HFO mode appeared to be a safe mode with a significant better oxygenation improvement (after the first 24 hours) and fewer cross-over rates, it failed to show differences as regards mortality or LOS when compared to the CMV adopting protective lung strategy. In PARDS, HFO had a superior advantage in improving oxygenation, yet with no significant mortality improvement, as multi-organ dysfunction syndrome (MODS) was the most common cause of death in our study and not refractory hypoxemia which is the main problem in PARDS; highlighting that mortality in PARDS is multi-factorial and may not depend only on how fast oxygenation improves.

High frequency oscillation ventilation treats respiratory distress syndrome of premature

Objective To explore the application of high frequency oscillation in the area of respiratory distress syndrome (RDS) of premature. Methods A total of 101 cases with RDS of premature was collected who needed the machine support in neonatal intensive care unite (NICU) during 2010.11.01-2011.10.30. Forty one cases (high frequency oscillation group) received the high frequency oscillation, while 60 cases received the common ventilation (Control Mechanical Ventilation group; control group). The results of blood gas analysis were recorded before ventilation, after ventilation for 2 hours, after ventilation for 12 hours, and after ventilation for 24 hours. The chest X-Ray and the complication were examined. Results The result of the blood-gas before ventilation, after ventilation for 2 hours, after ventilation for 12 hours, and after ventilation for 24 hours, FIO2, PO2, PCO2, and Pa(A-a) were statistically analyzed, and F-value was 16.202, 14.764, 16.135, 8.434, P<0.01. For chest X-ray in high frequent oscillation group, there were 36 cases who had improved after ventilation 24 hours and all had improved after ventilation 72 hours; however, in common ventilation group, there were 30 cases who had improved after 24 hours and 50 cases had improved after 72 hours, χ2=15.372 and 7.584, P<0.01, there was statistical difference for two groups. However, there were not different in cerebral injury /healing damage and retinopathy of prematurity (ROP) for two groups. Conclusions High frequency oscillation is an effective way to treat RDS of premature. Key words: High-frequency ventilation; Respiratory distress syndrome, newborn/TH

NF‐kappaB in the lungs of premature rabbits during mechanical ventilation—comparison between conventional mechanical ventilation (CMV) and high‐frequency oscillation (HFO)

The purpose of this study is to compare pulmonary nuclear factor-kappaB (NF-kappaB) activity of conventional mechanical ventilation (CMV) with that of high-frequency oscillation (HFO) in premature rabbit lungs. For surfactant-depleted model, we used premature rabbits in order to exclude the effect of lung lavage on the activation of NF-kappaB. The premature rabbits were delivered at a gestational age of 27 days by hysterotomy. Both modes of the ventilator were set at the same MAP and FiO(2). We used animals that had PCO(2) levels of approximately 50-mmHg. Animals were sacrificed after 1-hr ventilation with CMV or HFO. Then activity of pulmonary NF-kappaB was assessed. We observed that NF-kappaB activity was higher in the lungs of CMV compared with those of HFO, as measured by Western blot analysis. The activity level of NF-kappaB in the lungs measured by ELISA was significantly higher in CMV group than in HFO group. We conclude that a higher level of NF-kappaB activation was associated with CMV when compared to HFO.

High-Frequency Oscillation and Chronic Lung Disease in Very Low Birth Weight Infants

To the Editor. The study by Rimensberger et al1 suggests that early institution of high-frequency oscillation (HFO) for the treatment of respiratory distress syndrome improves the pulmonary outcome in ventilated very low birth weight infants. Unfortunately, there are flaws in study design that limit the validity of this conclusion. First, the 2 study cohorts were not concurrent. Most of the infants in the experimental cohort treated with HFO were born in 1997 and 1998, whereas those in the historical control cohort treated with conventional mechanical ventilation were born in 1994 and 1995. Subtle differences in clinical management might have been unavoidable in the 2-year period that separates these cohorts and contributed to the difference in the pulmonary outcome. Second, the statistical basis for selecting the specific number of infants in each cohort is not provided. Without appropriate power analysis, the statistical validity of comparisons between cohorts is difficult to confirm. Third, the retrospective nature of the study raises questions about uncontrolled data collection and problems with data retrieval, both inherent problems of a retrospective study design. Fourth, what is most striking is that there is no discussion of the common complications, such as symptomatic patent ductus arteriosus and airway infection, both of which are strong contributors to the development of chronic lung disease. And fifth, there is no discussion of the nutritional management of the infants. Nutrition plays a big role in the process of healing from lung injury. Thus, although the zero incidence of chronic lung disease in very low birth weight infants ventilated with HFO appears to be a remarkable achievement indeed, the enthusiasm for accepting this conclusion is dampened by the flawed study design. The subtle message that a single ventilation strategy can eliminate chronic lung disease, a disease of diverse causes, is misleading. What is …

High frequency oscillation ventilation compared to conventional mechanical ventilation plus exogenous surfactant replacement in rabbits

OBJECTIVES: (a) to evaluate the effect on oxygenation and ventilation of rabbits with induced surfactant depletion when they are submitted to a conventional mechanical ventilation, plus a small dose of exogenous surfactant; (b) to compare this group with another group submitted to a High Frequency Oscillation (HFO) without exogenous surfactant administration.METHODS: Twenty New Zealand White rabbits weighing (-/+ 3 kg) were anaesthetized and artificially induced to a endogenous surfactant depletion by successively lung lavage with normal saline (aliquots of 25 ml/kg) until to reach a persistent PaO(2) less than 100 mmHg when submitted to a mechanical ventilation in a pressure control mode with a target tidal volume of 10ml/kg, PEEP of 5cm H(2)O, FiO(2) 1.0, respiratory rate 30/min, and inspiratory time of 0.65 s. Then the rabbits were divided in (a) CMV+S group, submitted to a conventional mechanical ventilation plus exogenous surfactant replacement; (b) HFO group, submitted to a High Frequency Oscillation Ventilation. Arterial blood gases were measured at control period, post lung lavage, 15, 16 and 120 minutes after treatment started. The groups were compared using Student t test.RESULTS: The post lung lavage PaO(2) in both groups was lower than 50mmHg (p=0.154), increasing after 15 min of treatment to 254 mmHg (CMV+S) and 288 mmHg (HFO, p=0.626). The PaO(2) at 60 and 120 minutes were higher (p=0.001) in the HFO group (431 e 431 mmHg) when compared with the CMV+S group, which showed a progressive fall (148 e 126 mmHg). At 60 minutes of treatment, the PaCO(2) was lower (p=0.008) in the CMV+S group (29 versus 41 mmHg).CONCLUSIONS: In ARDS animal model a protect mechanical ventilation strategy as HFO by itself promotes a fast and persistent increase in the oxygenation, with superior levels than those observed in animals treated with conventional mechanical ventilation plus exogenous surfactant replacement.

First intention high-frequency oscillation with early lung volume optimization improves pulmonary outcome in very low birth weight infants with respiratory distress syndrome.

The lack of decline in chronic lung disease of prematurity despite the generalized use of surfactant and alternative modes of ventilation such as high-frequency oscillation (HFO) has been attributed to some misunderstanding of how HFO has to be used. We used a new ventilatory strategy in very low birth weight (VLBW) infants, by initiating HFO immediately after intubation and attempting early lung volume optimization before surfactant was administered. The outcome of 32 VLBW infants, managed with first intention HFO over a period of 24 months (September 1, 1996 and August 31, 1998) was compared by chart review with 39 historical controls, consecutively managed with conventional mechanical ventilation (CMV) over a period of 24 months (January 1, 1994 and December 31, 1995). An 11-bed tertiary care pediatric and neonatal intensive care unit of a university teaching hospital. The 2 groups of patients were similar in demographic distribution of birth weight, gestational age, race, and gender. Patients on first intention HFO were ventilator-dependent (median [95% confidence interval]: 5 [3-6] vs 14 [6-23] days) and oxygen-dependent (12 [4-17] vs 51 [20-60] days) for a shorter time than patients on CMV. The incidence of chronic lung disease at 36 weeks of gestational age was significantly lower in the HFO group compared with the CMV group (0% vs 34%). First intention HFO with early lung volume optimization shortened the need for respiratory support and improved pulmonary outcome of VLBW infants with respiratory distress syndrome significantly.

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.