Conventional versus High-Frequency Chest Wall Oscillation Care among Critically Ill Patients: A Comparative Nursing Evaluation of Respiratory Outcomes

Shimaa Abdelnaby Kamel^1*, Mogedda Mohamed Mehany¹, Marwan Nasreldin Mohammed², Naglaa Ahmed Ahmed¹

¹Department of Critical Care and Emergency Nursing, Faculty of Nursing, Assiut University, 2072350 Assiut Governorate, Egypt

²Department of Chest Diseases and Tuberculosis, Faculty of Medicine, Assiut University, 2072350 Assiut Governorate, Egypt

Corresponding Author Email ID: shimaa1993@aun.edu.eg

ABSTRACT

Background: The critical care nurse plays a significant role in applying airway clearance methods, including conventional chest wall physiotherapy as well as High-Frequency Chest Wall Oscillation (HFCWO), which became a therapeutic modality to mobilize mucus in different respiratory pathologies. Objectives: To evaluate respiratory outcomes following application of conventional versus high-frequency chest wall oscillation care among critically ill patients. Methods: A quasi-experimental research design was conducted at the respiratory Intensive Care Unit (ICU), Assiut University Hospital, Egypt, on a purposive sample of 60 adult critically ill patients. Patients were selected and assigned to two groups: 30 in the conventional group and 30 in the HFCWO group. Tools: Three tools were utilized in this study I. Clinical and Demographic Profile. II. Respiratory system assessment. III. Patients’ Outcomes. Results: As regards arterial blood gases, there were significant time effects for Partial Pressure of Oxygen in Arterial Blood (PaO₂) and Arterial Oxygen Saturation (SaO₂). Significant time × group interactions were observed for both variables, indicating greater improvement in the HFCWO group. There were significant differences in volume of secretion on the fourth (p=0.042*) and seventh (p=0.017*) days. Additionally, the HFCWO group's ICU stay was shorter than that of the conventional group, with a statistically significant difference (p=0.032*). Conclusion: HFCWO therapy was more effective in improving respiratory outcomes and decreasing the length of ICU stay than conventional chest physiotherapy. These results support replication of this study using a larger probability sample in several hospitals in Upper Egypt.

Keywords: Critically Ill Patients; High-Frequency Chest Wall Oscillation; Nursing Evaluation; Respiratory Outcomes

INTRODUCTION

Many critically ill patients often have an increased risk for respiratory infection, sputum retention and a greater number of them may require intubation and mechanical ventilation. Since the inflammatory response increases the production and accumulation of mucus in the airways, conventional and unconventional techniques of secretion removal are used (Costa et al., 2026). Chronic Obstructive Pulmonary Disease (COPD) is a clinical disease that is characterized by persistent coughing, excessive secretions, and shortness of breath. The key characteristics are abnormal overproduction of mucus, which often contributes to a decrease in symptom stability and patients becoming vulnerable to repeated disease exacerbations despite optimal drug treatment (Mari et al., 2025). Exacerbations also worsen quality of life and increase the likelihood of future episodes (Huang et al., 2025).

COPD is a progressive respiratory disorder and predominantly affects smokers and individuals older than 40 years, with prevalence increasing with advancing age. It remains a major global cause of morbidity and mortality (Singh et al., 2023). According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), quitting smoking is one of the most effective methods to prevent and manage COPD. It lowers exposure and treatment-related expenses (Ilyas & Iram, 2017). Overall, despite advances in management, further improvement is still needed to enhance treatment effectiveness and prognosis, particularly during exacerbations (Khan et al., 2023).

Management of airway clearance has been a key component of treatment to facilitate mobilization and removal of pulmonary secretions, which is essential for managing acute respiratory diseases as well as maintaining respiratory health. Effective airway clearance starts with identifying secretions in the airway and ends with expectoration (Gipsman et al., 2023). Conventional chest physiotherapy, positive expiratory pressure-based systems, modified postural drainage, or therapeutic positioning are airway clearance techniques. Furthermore, mechanically assisted modalities like high-frequency chest wall oscillation and high-frequency chest wall compression have become more clinically useful in mucus mobilization and expectoration by applying rapid oscillatory or percussion forces to the thoracic wall (Marin et al., 2024).

HFCWO delivers external chest compression through an inflatable vest connected to an air-pulse generator. By applying oscillations at varying frequencies, the technique enhances mucus mobilization from both central and peripheral airways (Rai & Sharma, 2026). HFCWO has been effectively used in patients with COPD (Costa et al., 2026). HFCWO appears to be more effective in improving pulmonary function and exercise tolerance, particularly in advanced stages of obstructive disease (Tahir et al., 2026).

The critical care nurse has a vital role in the patient's care who is receiving HFCWO care through continuous assessment of the hemodynamic status and monitoring oxygenation, breath rate, sounds, cough effectiveness, degree of dyspnea, and characteristics of respiratory secretions before, during, and after care as well as delivering tailored education on disease management and self-care strategies to reduce the risk of exacerbations (Wang et al., 2025). In addition, nurses are responsible for ensuring correct device application; adjusting parameters; and monitoring patient tolerance and comfort, as well as potential adverse effects such as desaturation, fatigue, or hemodynamic instability. Nurses’ conceptualization and integration of impaired airway clearance within the nursing process are very heterogeneous (Gaspar et al., 2024).

Despite these reported benefits, limited evidence is available regarding the effectiveness of HFCWO in patients with COPD, particularly from a nursing perspective. Therefore, this study aimed to evaluate the use of HFCWO in patients with COPD admitted to the respiratory intensive care unit.

Significance of the Study

In the respiratory ICU at Assiut University Hospital, patients commonly suffer from dyspnea and ineffective airway clearance. Accordingly, some patients receive conventional chest physiotherapy, and others receive HFCWO care, who show more respiratory improvement, as evidenced by the medical records of patients from May 2023 to May 2024 of Assiut University Hospital Record. Initiation of HFCWO therapy showed a substantial reduction in the number of hospitalizations and improved quality of life and lung function (Quissesa et al., 2021). Focused pulse HFCWO therapy improved respiratory function and quality of life in patients with moderate to severe COPD, enhanced daily activity performance, and reduced exacerbation rates (Pestelli et al., 2024).

Aim of the Study

To evaluate respiratory outcomes following application of conventional versus high-frequency chest wall oscillation care among critically ill patients.

Research Hypothesis

H₀: Patients who are using a high-frequency chest wall oscillation device will not exhibit any change in respiratory function or ICU stay compared to those who are receiving conventional chest physiotherapy.

H₁: Patients who are using a high-frequency chest wall oscillation device will exhibit more improvement in respiratory function compared to those who are receiving conventional chest physiotherapy.

H₂: Patients who are using a high-frequency chest wall oscillation device will exhibit a shorter ICU stay than those who are receiving conventional chest physiotherapy.

METHODOLOGY

Study Design

The study was conducted by using a quasi-experimental research design.

Setting

The study was conducted at the respiratory intensive care unit at Assiut University Hospital, Egypt.

Sample

A purposive sample of sixty adult patients who met the eligibility criteria was assigned sequentially to the conventional group first, followed by the HFCWO group, with thirty patients in each group from August 2024 to March 2025.

Inclusion criteria

All oriented non-mechanically ventilated critically ill patients who were newly admitted with age (18 to ≤ 65 yrs), diagnosed with exacerbation of COPD, and suffered from dyspnoea or difficult airway clearance (Saad et al., 2023).

Exclusion criteria

Patients with brain death, pulmonary oedema, pulmonary embolism, terminal stage of cancer, or subcutaneous emphysema.

The sample size was calculated according to the study's findings by Farag and Mariam (2018). By comparing two means of SaO2 pre and post intervention with a power of 80% and an alpha 5%. The mean difference was 2.3, with a standard deviation of 3.8 in the conventional group and 2.2 in the HFCWO group. It was calculated that the minimum sample size required is 30 for each group.

Figure 1: Flowchart of Patient’s Selection Criteria

Study Tools

Three tools were utilized by the researcher after reviewing the related literature.

Tool I

Clinical and Demographic Profile Ge et al. (2023); it was developed by the researcher and included.

Part I

Patient characteristics and clinical data, such as age, gender, and clinical presentation. It also included the Smoking Index formula, which is determined by multiplying the number of years of smoking by the number of cigarettes smoked daily (Philippe et al., 2025).

Part II

Laboratory measurements, which included results of Arterial Blood Gases (ABGs), pH, PaO₂, Partial Pressure of Arterial Carbon Dioxide (PaCO₂), Bicarbonate Ion (Arterial Bicarbonate) (HCO₃⁻), and SaO₂.

Tool II

Respiratory system assessment by Huang et al. (2022); it was developed by the researcher and included three parts.

Part I

Respiratory system assessment sheet, which was designed by a researcher to monitor respiratory rate, Fraction of Inspired Oxygen (FiO₂), and Oxygen Saturation by Pulse Oximetry (SpO₂). Moreover, the number of secretions was classified according to Karinja et al. (2015) into the following categories: 0 (absent), 1 (<6 ml), 2 (6-10 ml), or 3 (>10 ml) if present.

Part II

The 5-point Likert scale for dyspnea (5PLS); it was adopted from Weber et al. (2014). This psychometric tool measures breathlessness on a relative ordinal scoring system as (1) absence of dyspnea, (2) mild shortness of breath, (3) moderate shortness of breath, (4) severe shortness of breath and (5) the worst possible shortness of breath.

Part III

Cough Symptom Score (CSS) is the measure, which was adopted from Hsu et al. (1994) and used by Jakusova and Brozmanova (2023). The CSS was a two-part questionnaire considering the frequency and severity of coughing during the day and at night. Results were scored from 0 to 5, with 0 indicating no cough; 1 indicating cough for one short period; 2 indicating cough for more than two short periods; 3 indicating frequent coughing which did not interfere with usual daytime activities; 4 indicating frequent coughing that did not interfere with usual daytime activities; and 5 indicating distressing coughs most of the day.

Tool III

Patients' outcomes tool, which included expected patients' outcomes in terms of duration of ICU stay.

Procedure

The study included preparatory, implementation, and evaluation phases.

Preparatory Phase

In this phase official permissions were documented by hospital authorities at the respiratory intensive care unit and the faculty of nursing.

A panel of five critical care and emergency specialists assessed the content validity of tool I and tool II, part one, for appropriateness and clarity. 0.92 was the Content Validity Index (CVI).

The reliability of the study tools was assessed using Cronbach’s alpha. Tool I (α = 0.735) and Tool II (part one) (α = 0.761). The 5-point dyspnea scale (Tool II, part two) is a validated clinical tool, although Cronbach’s alpha was not reported in its original validation. Tool II (part three) (α = 0.928). Tool III included objective clinical outcomes, such as ICU stay, and did not require internal consistency testing.

The pilot study was implemented with six patients (10%) before implementation to evaluate objectivity and clarity of tools, required no modifications and excluded to prevent any potential bias.

Implementation Phase

Data Collection

The studied sample fulfilled the research criteria and was allocated into the conventional group and HFCWO group.

The conventional group received the conventional chest physiotherapy (vibration or percussion) twice daily for 7 consecutive days.

The HFCWO group received care with an available HFCWO device (Seoil Pacific Corp. company). Patients were seated comfortably, and parameters were adjusted on percussor mode, inhale pressure (40cm H₂o), oscillatory frequency (450 CPM), I:E ratio (1:2), and time set (30 minutes). Then patients performed deep breathing and coughing to expectorate secretions twice daily for 7 consecutive days and were assessed until discharge.

The HFCWO device is easy to use and time-efficient, offering a practical alternative to conventional chest physiotherapy. It consists of an air pulse generator and an inflatable vest that receives air pulses, which compress the chest wall and help in mobilizing tracheal mucus. Assessment of patient files pre-intervention for the following data: age, gender, clinical presentation, and smoking history; smokers are classified as follows: mild smoker is SI ≤ 200, moderate smoker is 200 < SI < 400 and heavy smoker is SI ≥ 400. During the implementation period, in collaboration with the nursing staff, the researcher evaluated and recorded results of ABGs, respiratory rate, SpO₂, FiO₂, presence and number of secretions, if present. Also, presence or absence of dyspnea by using the 5-point Likert scale for dyspnea, daytime and nighttime cough symptoms by using CSS pre-intervention, 4^th, and 7^th day.

Evaluation Phase

Each included patient in this study was evaluated for all assessed tools for improvement of overall respiratory outcomes pre-intervention, on the 4^th, and on the 7^th day and evaluated for length of ICU stay.

Statistical Analysis

Statistical analyses were performed using IBM SPSS Statistics version 26. Categorical variables were presented as frequencies and percentages and compared using the chi-square test or Fisher’s exact test, as appropriate. Continuous variables were expressed as mean ± standard deviation for normally distributed data or median (interquartile range) for non-normally distributed data, and an independent samples t-test or Mann–Whitney U test was used for analysis. Repeated measures ANOVA was used for repeated measurements. A p-value < 0.05 was considered statistically significant.

Ethical Considerations

The researchers obtained ethical clearance from the Ethical Research Committee of the Faculty of Nursing, Assiut University, Egypt, with ethical code 1120240830 on 1^st July 2024.

RESULTS

Table 1: Baseline Demographics and Clinical Characteristics of Patients in HFCWO and Conventional Groups

Item		HFCWO group (n=30)	Conventional group (n=30)	p-value	Test	Effect Size	CI 95%	Interpretation
Age Groups	18 to < 30 yrs.	2(6.7%)	2(6.7%)	0.437	Chi-square test χ²(3) = 2.72	Cramér’s V = 0.21	0.00 to 0.44	Small effect
	30 to < 40 yrs.	2(6.7%)	6(20%)
	40 to < 50 yrs.	8(26.7%)	5(16.7%)
	50 to ≤ 65 yrs.	18(60%)	17(56.7%)
Gender	Male	18(60%)	21(70%)	0.589	Fisher’s exact	Phi = 0.105	- 0.15 to 0.35	Small effect
	Female	12(40%)	9(30%)
Smoking Status	Non-smokers	12(40%)	18(60%)	0.033*	Chi-square test χ²(3) = 8.71	Cramér’s V = 0.38	0.14 to 0.58	Moderate effect
	Mild	6(20%)	0(0%)
	Moderate	4(13.3%)	7(23.3%)
	Heavy	8(26.7%)	5(16.7%)
Length of ICU Stays (days)		8 (IQR 3)	9 (IQR 5)	0.032*	Mann-Whitney U	r = 0.28	0.02 to 0.49	Small–moderate effect

*Statistically significant difference, p<0.05, Values are presented as n (%) for categorical variables and median Interquartile Range (IQR) for continuous variables, Between-group comparisons used Chi-square test, Fisher’s exact test, or Mann–Whitney U test as appropriate, Effect sizes with 95% confidence intervals are reported

Table 1 clarifies that baseline demographic characteristics were largely similar between the HFCWO and conventional groups. However, there is a statistically significant difference between both groups regarding Smoking history (p = 0.033*). The HFCWO group experienced a shorter ICU stay than those in the convntional group (p = 0.032*).

Figure 2: Comparison of Clinical Presentation between the High-Frequency Chest Wall Oscillation (HFCWO) Group and Conventional Group at Admission

Figure 2 compares the percentages of patients presenting with cough, fever, wheezing, and chest pain at admission in the HFCWO and conventional groups. Patients could present with more than one symptom; therefore, percentages are not mutually exclusive. No statistically significant differences between the two groups (p > 0.05). Cough was the most common symptom in both groups.

Table 2: Comparison of Arterial Blood Gas Parameters between the HFCWO and Conventional Groups over Time

(ABGs)	Group (n=30)	Pre intervention	4^th day	7^th day	p (Time)	p (Interaction)	p (group)	Effect Size (η²)	Interpretation
pH	HFCWO Group	7.34 ± 0.10	7.38 ± 0.07	7.39 ± 0.06	0.002	0.859	0.019	0.113	Significant effect (time+group)
	Conventional Group	7.38 ± 0.12	7.42 ± 0.07	7.42 ± 0.04
	CI 95%	-0.87 to 0.15	-0.85 to 0.20	-0.82 to 0.17
PaO₂ _(mmHg)	HFCWO Group	72.53 ±21.03	83.23 ± 16.40	85.90 ± 14.92	0.020	0.033	0.013	0.078	Significant improvement
	Conventional Group	72.53 ± 12.96	73.57 ± 15.33	72.77 ± 11.04
	CI 95%	-8.86 to 8.86	3.91 to 15.40	7.55 to 18.70
PaCO₂ _(mmHg)	HFCWO Group	60.13 ± 19.05	58.32 ± 16.48	60.67 ± 18.41	0.453	0.658	0.200	0.014	Non-Significant
	Conventional Group	57.40 ± 23.68	53.29 ± 17.71	53.64 ± 10.81
	CI 95%	-8.82 to14.28	-0.53 to10.58	0.40 to 14.46
HCO₃⁻ _(mEq/L)	HFCWO Group	33.63 ± 8.80	35.98 ± 14.51	36.38 ± 8.63	0.303	0.603	0.401	0.020	Non-Significant
	Conventional Group	33.05 ± 10.27	33.97 ± 8.64	33.52 ± 6.89
	CI 95%	-4.68 to 5.84	-3.24 to 7.26	-2.62 to 8.33
SaO₂ _(%)	HFCWO Group	90.13 ± 6.66	94.30 ± 3.54	93.23 ± 5.67	< 0.001	0.022	0.331	0.145	Significant time × group interaction
	Conventional Group	91.57 ± 3.13	92.30 ± 3.87	95.70 ± 2.67
	CI 95%	-3.25 to 0.37	-0.40 to 3.60	-4.92 to 0.01

*Statistically significant difference, p<0.05

Table 2 presents significant time effects for PaO₂ and SaO₂. Significant time × group interactions were observed for both variables, indicating greater improvement in the HFCWO group. However, pH showed a significant group effect without interaction, while PaCO₂ and HCO₃⁻ showed no significant differences. Effect sizes ranged from small to large, with the greatest effect observed for SaO₂.

Table 3: Respiratory Assessment Parameters in HFCWO and Conventional Groups

Group		HFCWO group (n=30)	Conventional group (n=30)	P-value	Median Difference	Effect size (r)	CI 95%	Interpretation
Pre intervention	Respiratory Rate (breaths/min)	25 (3.3)	26.5 (6)	0.152	-1.50	0.18	-0.07 to 0.41	Small effect
	SpO₂ (%)	90.5 (4)	91 (5.5)	0.727	- 0.50	0.04	-0.21 to 0.29	Trivial effect
	FiO₂ (%)	40 (15)	40 (10)	0.041*	0.00	0.26	0.01 to 0.49	Small effect
4^th day	Respiratory Rate (breaths/min)	21 (2.5)	21 (4.3)	0.715	0.00	0.05	-0.20 to 0.30	Trivial effect
	SpO₂ (%)	94 (3.3)	93 (4.3)	0.352	1.00	0.12	-0.14 to 0.37	Small effect
	FiO₂ (%)	31 (9)	35 (9)	0.529	- 4.00	-0.08	-0.17 to 0.33	Trivial effect
7^th day	Respiratory Rate (breaths/min)	23 (4.3)	24 (5.5)	0.004*	- 1.00	-0.37	0.12 to 0.58	Moderate effect
	SpO₂ (%)	93 (1.3)	92 (4.3)	0.055	1.00	0.25	-0.01 to 0.49	Small effect
	FiO₂ (%)	28 (7)	28 (4)	0.969	0.00	0.01	-0.24 to 0.26	No effect

*Statistically significant difference, p<0.05, Data are presented as median Interquartile Range (IQR), Mann–Whitney U test

Table 3 indicates that respiratory assessment parameters were generally comparable between the two groups. However, the HFCWO group demonstrated a significantly lower respiratory rate than the conventional group (p = 0.004*) on 7th day, while no significant between-group differences were observed for SpO₂ or FiO₂.

Table 4: Comparison between the Two Groups Regarding the Number of Secretions across the Assessment Days

Number of Secretions		HFCWO group (n=30)	Conventional group (n=30)	p-value	df
Pre-intervention	< 6 ml	7 (23.3%)	11 (36.7%)	0.104	2
	6 – 10 ml	19 (63.30%)	19 (63.30%)
	> 10 ml	4 (13.3%)	0 (0.0%)
At 4^th day	No Secretion	1 (3.3%)	4 (13.3%)	0.042*	3
	< 6 ml	18 (60.0%)	12 (40.00%)
	6 – 10 ml	6 (20.0%)	13 (43.3%)
	> 10 ml	5 (16.7%)	1 (3.3%)
At 7^th day	No Secretion	18 (60%)	11 (36.67%)	0.017*	3
	< 6 ml	5 (16.7%)	15 (50%)
	6 – 10 ml	7 (23.3%)	3 (10%)
	> 10 ml	0 (0.0%)	1 (3.33%)

*Statistically significant difference, p<0.05, Fisher’s exact test

Table 4 demonstrates that there were significant differences in the volume of secretions observed on the fourth and seventh days (p = 0.042* and 0.017*, respectively), indicating greater improvement in secretion clearance among patients in the HFCWO group compared with the conventional group.

Table 5: Comparison between the Two Groups Regarding the 5-point Likert Scale for Dyspnoea

The 5-point Likert scale for dyspnoea		HFCWO group (n=30)	Conventional group (n=30)	p-value	df
Pre-intervention	Moderate Shortness of Breath	11 (36.7%)	6 (20%)	0.217	2
	Severe Shortness of Breath	16 (53.3%)	23 (76.7%)
	The Worst Possible Shortness of Breath	3 (10.0%)	1 (3.3%)
At 4^th Day	Absence of Dyspnoea	4 (13.3%)	0 (0.0%)	0.018*	2
	Mild Shortness of Breath	21 (70.0%)	17 (56.7%)
	Moderate Shortness of Breath	5 (16.7%)	13 (43.33%)
At 7^th Day	Absence of Dyspnoea	24 (80.0%)	15 (50.0%)	0.011*	4
	Mild Shortness of Breath	1 (3.3%)	10 (33.33%)
	Moderate Shortness of Breath	2 (6.7%)	3 (10.0%)
	Severe Shortness of Breath	2 (6.7%)	2 (6.7%)
	The Worst Possible Shortness of Breath	1 (3.3%)	0 (0.0%)

*Statistically significant difference, p<0.05, Fisher’s exact test

Table 5 demonstrates that baseline dyspnoea scores were comparable between the two groups. Significant improvements in dyspnoea were observed in the HFCWO group compared with the conventional group on 4^th day (p = 0.018*) and 7^th day (p = 0.011*).

Table 6: Comparison between the Two Groups in Relation to Cough Symptom Score (daytime)

Cough Symptom Score (daytime)		HFCWO Group (n=30)	Conventional Group (n=30)	p-value	df
Pre-intervention	Cough for More Than 2 Short Periods	1 (3.3%)	0 (0.0%)	1.000	3
	Frequent Coughing Which Did Not Interfere with Usual Daytime Activities	19 (63.30%)	20 (66.70%)
	Frequent Coughing Which Did Interfere with Usual Daytime Activities	7 (23.3%)	6 (20.0%)
	Distressing Coughs Most of the Day	3 (10.0%)	4 (13.3%)
At 4^th day	No Cough During the Day	1 (3.3%)	0 (0.0%)	0.012*	4
	Cough for One Short Period	7 (23.3%)	0 (0.0%)
	Cough for More Than Two Short Periods	17 (56.7%)	21 (70.0%)
	Frequent Coughing, Which Did Not Interfere with Usual Daytime Activities	5 (16.7%)	9 (30.0%)
At 7^th day	No Cough During the Day	15 (50.0%)	9 (30.0%)	0.006*	4
	Cough for One Short Period	14 (46.7%)	12 (40.00%)
	Cough for More Than Two Short Periods	0 (0.0%)	8 (26.7%)
	The Frequent Coughing did not Interfere with Regular Daytime Activities.	0 (0.0%)	1 (3.3%)
	Distressing Coughs Most of the Day	1 (3.3%)	0 (0.0%)

*Statistically significant difference; p<0.05; Fisher’s exact test

Table 6 indicates that patients in the HFCWO group showed significantly greater improvement in daytime cough symptoms than those in the conventional group on the fourth and seventh assessment days (p < 0.05). Regarding night-time cough symptoms, no significant differences were observed between both groups throughout the intervention period (p > 0.05), although both groups demonstrated gradual improvement over time.

*Statistically significant difference; p<0.05

Figure 3: Comparison of Patients' Outcomes between the HFCWO and Conventional Groups

Figure 3 demonstrates a statistically significant difference in patients' outcomes between the HFCWO and conventional groups (p = 0.027*). Most patients were transferred to the chest ward, with a higher proportion in the HFCWO group (73.33%) than in the conventional group (66.66%).

DISCUSSION

This study emphasized the critical role of nursing assessment and intervention in optimizing the effectiveness of HFCWO therapy, which has been used as adjunctive treatment to improve lung function since it has demonstrated safety, tolerability, and improved compliance among patients with excessive secretions (Marin et al., 2024). Therefore, this study was to evaluate respiratory outcomes following application of conventional versus high-frequency chest wall oscillation care among critically ill patients.

Considering the statistical analysis, no statistically significant difference was observed between the groups regarding gender distribution (p > 0.05). Most patients were in age group (50 to ≤ 65 yrs.). Moreover, most of both groups were men (60% in the HFCWO group and 70% in the conventional group). These findings were in line with Samir et al. (2024), who found that the approximately 51 to 60 years age range was observed in nearly half of the study group (48.9%) and (62.2%) of the control group, and the majority of them were males. From the researcher's opinion, COPD seems to be more common in males, patients with a history of smoking, or advanced age. Smoking history analysis showed that the smoking status in the HFCWO and conventional groups was statistically significant (p = 0.033*) as non-smokers were represented in a higher percentage in the conventional group (60% compared to 40%). This observation was contrary to Farag and Mariam (2018), who found no statistically significant variation in the smoking status among the groups under study in terms of pack-years (p = 0.32).

Through continuous nursing monitoring of respiratory parameters, there were significant time effects for PaO₂ and SaO₂. Significant time × group interactions were observed for both variables, indicating greater improvement in the HFCWO group. These results agreed with Cheng et al. (2022), who reported the improvement of post-intervention PaO₂ and a decrease in PaCO₂ (p < 0.05). Also, these findings were agreed with by Farag and Mariam (2018), who mentioned that post-treatment assessment for both HFCWO and Flutter groups demonstrated that oxygenation parameters (PaO₂, SaO₂%) were significantly improved. Nevertheless, this was contrary to Longhini et al. (2020), who did not find any differences in ABGs among studied groups. These findings highlight that the success of HFCWO therapy is strongly influenced by skilled nursing care. After seven days of intervention, the HFCWO group showed a lower respiratory rate with a statistically significant difference (p = 0.004*) compared with another group. This is similar to Reda et al. (2024), who mentioned that “Additionally, a significant difference in RR was found in this study between the conventional group and the intervention group (who got both manual chest physical therapy and a cough assist device) (p = 0.004*).”

Nursing assessment before, during, and after treatment includes evaluation of cough effectiveness and secretion characteristics. It was observed that the management of secretions became better by 4^th and 7^th day (p = 0.042* and 0.017*), respectively. 60% Of the HFCWO group displayed no distinguishable secretions versus (36.67%) in the conventional group at 7^th day. This is inconsistent with Quissesa et al. (2021), who associated high-frequency oscillation with the best airway clearance, and also supported by Wang and Leng (2026), who stated that the sputum volume of patients on postoperative days 2, 3, 4, and 5 in the study group was significantly lower than that in the control group (p < 0.05). However, these results contradicted those of Lin et al. (2017), who reported that “no statistically significant difference in sputum volume was observed between the two groups (p = 0.085)”.

On the topic of dyspnea, these results revealed that the HFCWO group showed improvement of dyspnea severity over the conventional group on 4^th and 7^th days with statistically significant differences (p = 0.018* and 0.011*), respectively. These findings agreed with Ahmed et al. (2024), who stated that compared to the Lung Flute, HFCWO provides more significant improvements in pulmonary function and exertional dyspnoea in post-COVID men with COPD. But these results were contrary to Huang et al. (2022), who found that the severity of dyspnea did not significantly improve in COPD patients following the HFCWO.

In addition, the HFCWO group experienced greater improvement in daytime cough symptoms compared to the conventional group on the 4^th and 7^th days, with statistically significant differences (p = 0.012* and 0.006*), respectively. These findings were supported by Farag & Mariam (2018), who stated that the dyspnea score, coughing, and mucus production were considerably enhanced in the HFCWO and Flutter groups. Expectoration and airway clearance are facilitated by adjunctive treatment with either HFCWO or Flutter devices.

But night-time cough symptoms were statistically unchanged between two groups. From a researcher's point of view, this may be due to physiological changes that occur during sleep, including congestion, immobility, or changes in respiratory mechanics. Patients who received HFCWO care had a shorter ICU stay than those in the conventional group, with statistical significance (p = 0.032*). Cheng et al. (2022) observed similar results, showing that “Group A (Intervention Group)” patients exhibited a significantly shorter length of stay than “Group B (Control Group)” with p values < 0.05. However, Lee et al. (2011) observed no statistically meaningful group differences in length of stay.

Limitations

A major limitation of this study was the small sample size, which may have reduced the statistical power and limited the generalizability of the findings. The number of eligible patients was restricted by the inclusion criteria, as most patients admitted to the respiratory ICU required mechanical ventilation and prolonged ICU stays, while many others were discharged within five days of ICU admission. In addition, some eligible patients declined to participate. Therefore, the findings should be interpreted with caution.

Future Scope

Further research should involve larger and more representative samples to confirm these findings, clarify the effectiveness of HFCWO in critically ill patients with different respiratory conditions, and improve the generalizability of the results. Future studies should also focus on establishing evidence-based treatment protocols and evaluating the long-term effects of HFCWO on respiratory function.

CONCLUSION

This study demonstrated that HFCWO was more effective than conventional chest physiotherapy in improving respiratory and clinical outcomes among patients with COPD admitted to the respiratory intensive care unit. Patients in the HFCWO group showed significant improvements in dyspnea scores, respiratory rate, daytime cough symptoms, and secretion clearance. They were also more likely to be transferred to the respiratory unit and had a shorter ICU length of stay. These findings contribute to nursing knowledge by supporting the use of HFCWO as an evidence-based airway clearance for critically ill patients with COPD. Integrating HFCWO into routine nursing care may improve patient outcomes.

CRediT Authorship Contribution Statement

Sh.A.K.: Conceptualization, methodology, data curation, formal analysis, writing – original draft. M.M.M: Supervision, data curation, revision and editing. M.N.M.: Supervision, revision and editing. N.A.A.: Clinical supervision, data curation and editing.

AI Assistance Declaration

The authors declare that generative AI tools (such as ChatGPT) were used only for language enhancement and grammar correction during the preparation of this manuscript. The authors carefully revised the content and will take full responsibility for the final version of the manuscript.

Conflict of Interest

There were no competing interests among the authors.

ACKNOWLEDGEMENT

The authors truly appreciated all patients, doctors, and nurses who participated in this study at the respiratory ICU.

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