Instantaneous responses to high-frequency chest wall oscillation in patients with acute pneumonic respiratory failure receiving mechanical ventilation

Abstract

Background:Endotracheal intubation and prolonged immobilization of patients receiving mechanical ventilation may reduce expectoration function. High-frequency chest wall oscillation (HFCWO) may ameliorate airway secretion movement; however, the instantaneous changes in patients’ cardiopulmonary responses are unknown. Moreover, HFCWO may influence ventilator settings by the vigorous oscillation. The aim of this study was to investigate these issues.Methods:Seventy-three patients (52 men) aged 71.5 ± 13.4 years who were intubated with mechanical ventilation for pneumonic respiratory failure were recruited and randomly classified into 2 groups (HFCWO group, n = 36; and control group who received conventional chest physical therapy (CCPT, n = 37). HFCWO was applied with a fixed protocol, whereas CCPT was conducted using standard protocols. Both groups received sputum suction after the procedure. Changes in ventilator settings and the subjects’ responses were measured at preset intervals and compared within groups and between groups.Results:Oscillation did not affect the ventilator settings (all P > 0.05). The mean airway pressure, breathing frequency, and rapid shallow breathing index increased, and the tidal volume and SpO2 decreased (all P < 0.05). After sputum suction, the peak airway pressure (Ppeak) and minute ventilation decreased (all P < 0.05). The HFCWO group had a lower tidal volume and SpO2 at the end of oscillation, and lower Ppeak and tidal volume after sputum suction than the CCPT group.Conclusions:HFCWO affects breathing pattern and SpO2 but not ventilator settings, whereas CCPT maintains a steadier condition. After sputum suction, HFCWO slightly improved Ppeak compared to CCPT, suggesting that the study extends the indications of HFCWO for these patients in intensive care unit. (ClinicalTrials.gov number NCT02758106, retrospectively registered.)

Chest physiotherapy improves lung aeration in hypersecretive critically ill patients: a pilot randomized physiological study

“…Various mechanisms of action have been proposed for HFCWO: (1) augmentation of the expiratory flow, which increases the annular flow of mucus towards the oropharynx when exceeding by more than 10% the inspiratory peak flow [ 16 – 18 ]; (2) improvement of mucus rheological (spinnability and viscoelastic) properties [ 19 , 20 ]; (3) increase of ciliary motility by reflected stimulation of vagus nerve, in particular when the applied oscillations range between 11 and 15 Hz [ 21 ]; and (4) enhancement of the gas-liquid transport [ 16 , 22 ]. Recent findings showed that HFCWO, when compared to conventional physiotherapy, improves the amount of aerated lung regions and oxygenation of intubated patients in intensive care unit (ICU) [ 23 , 24 ].…”

Effects of High-Frequency Chest Wall Oscillation Expectoration System on Pulmonary Rehabilitation and Cortisol Function in Patients with Severe AECOPD

“…AECOPD has a complex pathogenesis, mostly involving viral or bacterial infections [22]. Increased serum levels of WBCs and interleukins suggest the presence of lower airway bacterial colonization, and abnormal inflammatory factors aggravate the disease [23].…”

Heat and moisture exchanger used in a cardiothoracic surgery intensive care unit: Airway resistance and changing interval

“…Airway secretions and sputum, which block the HMEs, may cause a sudden increase in airway resistance and eventually death. [ 27 ] Physicians and nurses in the ICU must inspect, if there are stains in the HMEs. The HMEs must be changed immediately, if stain occurs at any time.…”