Abstract
Objectives
Our aim is to investigate the effects of a innovative modular prone positioning tools on patients with acute respiratory distress syndrome (ARDS) caused by COVID-19 during awake prone positioning (AW-PP).
Methods
This prospective randomized controlled study initially enrolled 168 patients with COVID-19 due to ARDS. However, 92 were subsequently disqualified, leaving 76 patients who were randomly assigned to either the observation group (n = 38) or the control group (n = 38). The observation group utilized innovative modular prone positioning tools for non-invasive respiratory support (NIRS), while the control group used soft pillows for the same treatment. Data were collected on comfort levels, adverse events, and efficacy indicators. Additionally, the comfort, incidence of adverse events, and treatment efficacy in both groups were evaluated.
Results
The observation group had shorter the daily duration spent on executing the AW-PP (2.74 ± 0.86 min vs. 4.64 ± 1.02 min, P < 0.001), longer the daily total AW-PP (8.52 ± 1.01 h vs. 6.03 ± 0.66 h, P < 0.001), longer the daily duration until the first position adjustment (59.89 ± 12.73 min vs. 36.57 ± 8.69 min, P < 0.001), and lower the daily frequency of position adjustments during the AW-PP (11.03 ± 2.67 vs. 17.95 ± 2.58, P < 0.001) in comparison with the control group. No significant differences were observed in intubation rates, mortality, the daily number of hours under HFNO and NIV, escalated to NIV from HFNO, and hospital length of stay between the groups (P > 0.05). However, the observation group experienced significantly fewer adverse events, including kinking NIRS circuit, pain, shortness of breath, dizziness, and pressure ulcers (P < 0.05).
Conclusion
Innovative modular prone positioning tools improved efficiency, comfort, and reduced adverse events during AW-PP but did not affect intubation rates or mortality.
Supplementary Information
The online version contains supplementary material available at 10.1186/s40001-024-02252-1.
Keywords: Innovative modular prone positioning tools, Awake prone position, Acute respiratory distress syndrome, COVID-19, Randomized controlled trial
Introduction
Acute respiratory distress syndrome (ARDS) is a life-threatening condition primarily characterized by refractory hypoxemia and acute respiratory failure [1–3], posing a significant threat to patient survival [4–6]. Between 20% and 41% of severe COVID-19 patients develop ARDS, with a mortality rate exceeding 30% [7–9]. Prone positioning (PP) during mechanical ventilation improves the ventilation-perfusion ratio [10–12], increases lung volume [13, 14], promotes uniform pleural pressure distribution [15], enhances lung recruitment, and reduces ventilator-induced lung injury [16, 17]. These effects ultimately improve oxygenation and reduce mortality in ARDS patients. As a result, PP is now recommended in several guidelines for moderate-to-severe ARDS [18, 19]. In healthcare systems overwhelmed by COVID-19, PP has also been widely used for non-intubated, spontaneously breathing ARDS patients, significantly enhancing oxygenation and reducing mortality [20, 21].
Since the onset of the COVID-19 pandemic, awake prone positioning (AW-PP) has gained widespread acceptance for non-intubated, spontaneously breathing patients with ARDS [22]. Recommended by medical societies, AW-PP is recognized for its potential benefits, low risk, and ease of implementation, particularly as a non-invasive alternative to intubation in overwhelmed healthcare settings [23, 24]. The ESICM guidelines suggest that AW-PP improves oxygenation and reduces the need for invasive mechanical ventilation in non-intubated COVID-19 patients [25]. Studies on acute hypoxemic respiratory failure have demonstrated AW-PP efficacy in enhancing oxygenation and reducing intubation rates [8, 26–29]. Furthermore, large-scale meta-analyses and observational studies suggest that AW-PP not only lowers intubation rates in COVID-19-related hypoxemia but may also reduce mortality, supporting its role in managing respiratory failure [30, 31].
AW-PP in ARDS patients likely involves mechanisms similar to those in intubated patients, such as improved ventilation-perfusion matching, enhanced lung recruitment, and reduced mechanical strain, all of which optimize gas exchange, reduce ventilator-associated lung injury, and contribute to better clinical outcomes, including lower mortality and faster recovery [32, 33]. While intubated patients typically benefit more from prolonged prone positioning due to mechanical ventilation that improves oxygenation and reduces extracorporeal membrane oxygenation (ECMO) dependence, non-intubated patients face challenges in maintaining the position for extended periods due to reliance on spontaneous breathing [28, 34–36]. Non-intubated patients are at higher risk for discomfort, respiratory distress, hemodynamic instability, positional hypotension, and gastrointestinal complications, complicating AW-PP management and highlighting the need for further research to optimize its use in this group.
Patient adherence to AW-PP varies significantly, even in ICU settings, where daily duration varies from 1–2 hours to 8–10 hours [32]. Most studies report patients tolerate prone positioning for 2 to 3 h per session [27, 35, 36]. Eperatti et al. recommend a minimum of 6 h per day to reduce intubation risk, and at least 8 h to lower mortality risk [36]. However, the implementation of AW-PP remains challenging, with only 43% of patients able to adhere to the recommended plan of at least 6 h of prone positioning daily [35]. Recent evidence suggests longer durations of prone positioning are linked to better outcomes, indicating that maximizing the duration of prone positioning, as tolerated by the patient, can optimize therapeutic benefits [31, 36, 37].
Traditional prone positioning with soft pillows presents several challenges [38]. Soft pillows, although initially supportive, compress over time, increasing pressure on sensitive areas such as the eye sockets, chest, and abdomen. This leads to discomfort, conjunctival congestion, pressure injuries, and respiratory restrictions. Frequent repositioning, necessary to alleviate discomfort, increases the risk of skin breakdown and complicates the management of NIRS systems, potentially causing NIRS circuit kinks, mask misalignment, and airflow obstruction, which can undermine respiratory support. Additionally, manual repositioning places extra strain on healthcare workers, diverting attention from other critical tasks. These issues underscore the limitations of soft pillows in prolonged prone positioning, particularly in ARDS patients. To address these issues, we developed an innovative modular prone positioning tool designed for prone ventilation in ARDS patients, particularly those with COVID-19. The primary objectives were to improve patient comfort and minimize complications through the innovative modular prone positioning tools during AW-PP, while also providing a clinical reference for the safe and effective implementation of NIRS.
Materials and methods
Aim
The aim of this pilot study was to assess the effects of innovative modular prone positioning tools in patients with COVID-19 due to ARDS during AW-PP.
Design and setting
This study was a single-center, parallel randomized controlled trial conducted at Shanghai Fourth People’s Hospital affiliated to Tongji University.Participants were recruited between February 2023 to May 2024 using convenience sampling. This study was conducted in accordance with the Declaration of Helsinki and was approved by the Medical Ethics Committee of Shanghai Fourth People’s Hospital (No. SYLL2023008, Date of approval: 2 February 2023). This study was registered at the Chinese Clinical Trial Registry (No. ChiCTR2300068220). All the patients provided written informed consent.
sample size calculation
The sample size for this study was calculated using G*Power 3.1.9.2 software, informed by preliminary experimental data and prior clinical experience. The primary aim in this study was to assess improvements in patient comfort during prone positioning for COVID-19-induced ARDS. To detect statistically significant differences in comfort levels, we established a target power of 90% and an alpha level of 0.05. Based on effect sizes reported in comparable studies, including Minnis et al [39], which documented a median comfort improvement of 0.5 with a standard deviation of 1.2, we estimated an effect size of 0.75 for this study. This estimation ensured alignment with observed clinical outcomes and enhanced statistical robustness. Given these parameters, a minimum of 35 participants per group was required. Accounting for a potential 10% dropout rate, the final sample size was adjusted to 38 participants per group, totaling 76.
Participants
The included criteria were as follows: (1) older than 18 years of age; (2) had COVID-19 confirmed by positive SARS-CoV-2 reverse transcription polymerase chain reaction testing on nasopharyngeal or oropharyngeal swabs; (3) the X-ray examination confirmed multiple ground-glass opacities and infiltrates in both lungs; (4) hypoxemic respiratory failure; (5) HFNO or NIV for respiratory support and a PaO2/FiO2-ratio of less than 150 mmHg for more than an hour.
The exclusion criteria were as follows: (1) supplementing oxygen with a method besides HFNO or NIV; (2) the use of intravenous sedation during the prone position; (3) inability to assume prone, endotracheal intubation is immediately necessary; (4) severe hemodynamic instability; (5) previously had COVID-19 pneumonia intubation; (6) pregnant, pressure sores, currently experiencing pain or discomfort; (7) unable to comprehend study material either in writing or orally.
Randomization and blinding
An independent researcher randomized participants in a 1:1 ratio into either the control group or observation group using random sequences generated by SAS Statistics version 9.4 (SAS Institute Inc., Cary, NC). The assignments were placed in sequentially numbered, opaque-sealed envelopes to conceal participant allocation. Due to the nature of the intervention, it was not possible to blind the patients, caregivers, or therapists after group assignment. However, outcome assessors and data statisticians remained blinded to treatment allocation until all data analysis was completed.
Study intervention and protocol for NIRS usage
In the observation group, innovative modular prone positioning tools—including a head pad, chest pad, elbow pads, knee pad, and ankle pads—were used to facilitate NIRS (Fig. 1). These modular tools underwent rigorous testing, including X-ray inspection, flame retardancy assessments, non-toxicity evaluation, anti-static testing, and antimicrobial verification, to ensure compliance with strict medical device safety standards, guaranteeing patient safety (Supplement 1). The positioning procedure involved several steps: the head was supported by a head pad, the chest by a chest pad, and the extremities by elbow, knee, and ankle pads (Fig. 2). In the control group, NIRS was applied using soft pillows placed under the head, chest, knees, and ankles, with the patient's arms positioned either parallel to the sides of the body or alongside the head (Fig. 3). Patients in both groups were recommended to maintain the prone position for as long as they could tolerate it, with a target of at least 6 h per day. Based on prior studies indicating that longer durations improve oxygenation and reduce the need for intubation [36]. However, adjustments were made based on patient tolerance, clinical condition, and the occurrence of adverse events.
Fig. 1.
Innovative modular prone positioning tools
Fig. 2.
Implementation protocol for AW-PP using innovative modular prone positioning tools
Fig. 3.
The control group used traditional prone ventilation positioning therapy
Patients in both groups received NIRS through either HFNO or NIV based on their clinical conditions. HFNO was the initial therapy for all patients, delivering oxygen at a flow rate tailored to maintain adequate oxygen saturation levels (> 90%). Patients were escalated to NIV if they exhibited signs of deteriorating respiratory function, such as increasing respiratory rate (> 30 breaths per minute), persistent hypoxemia (SpO₂ < 88% despite HFNO), or clinical signs of respiratory distress. NIV was administered exclusively using facemasks as the interface, with parameters adjusted to achieve a positive end-expiratory pressure (PEEP) of 6 ~ 8 cm H₂O and a fraction of inspired oxygen (FiO₂) adjusted to maintain SpO₂ > 90%. The total daily hours of HFNO and NIV use were recorded for each patient. The criteria for switching between HFNO and NIV were consistent across both groups, and all escalations to NIV were documented.
The protocol required daily prone positioning sessions to continue until one of the following criteria was met: intubation, death, or clinical improvement, defined as the use of a standard nasal cannula or open face mask with an oxygen flow rate of ≤ 5 L/min for 12 h. Attending clinicians were permitted to withdraw patients from the trial at any time if they deemed prone positioning unsafe.
Standard care was provided to both groups throughout the study period in accordance with clinical practices at the participating hospitals. Intravenous sedation was not permitted during the study. The decision to intubate was ultimately at the discretion of the attending clinician, while adhering to local regulations. Although the use of prone positioning was a routine part of care for mechanically ventilated COVID-19 patients with moderate to severe ARDS, there was no standardized protocol for positioning after intubation.
Data collection
A total of 4 physicians and 8 nurses were designated as quality controllers, ensuring that at least one was on duty during each shift. Data collection followed standardized training on evaluation criteria, timing, and recording methods to ensure consistency in assessments. Data on sex, age, BMI, comorbidities (including obesity, hypertension, cardiovascular disease, diabetes, chronic pulmonary disease, and chronic kidney disease), NIRS type, HFNO flow rate, PEEP (NIV), FiO2, SpO2, PaO2, PaO2/FiO2, and SpO2/FiO2 were recorded at the time of enrollment. Additionally, the daily duration spent on executing the AW-PP, the daily total AW-PP, the daily duration until the first position adjustment and the daily frequency of position adjustments during the AW-PP were continuously recorded by healthcare providers using case report forms. Daily records included intubation status, mortality, hospital length of stay (LOS), daily number of hours under HFNO or NIV, escalated from HFNO to NIV and symptoms such as kinking NIRS circuit, pain, shortness of breath, dizziness, and pressure ulcers. All anonymized data were entered into a secure electronic case report form (OpenClinica®, OpenClinica LLC, Waltham, MA, USA).
Outcome measures
The primary outcomes included the daily duration spent on executing the AW-PP, the daily total AW-PP, the daily duration until the first position adjustment, and the daily frequency of position adjustments during the AW-PP. The secondary outcomes include daily number of hours under HFNO and NIV, escalated to NIV, hospital LOS, intubation rates, mortality, and adverse events within 30 days of enrollment. Adverse events included kinking NIRS circuit, pain, shortness of breath, dizziness, and pressure ulcers. The daily duration spent on executing the AW-PP was defined as the time from initiating AW-PP to achieving the desired position. The daily total AW-PP refers to the cumulative time spent in the AW-PP within a 24 h period. The daily duration until the first position adjustment was the duration a patient remained prone before the first postural change, while the daily frequency of position adjustments during the AW-PP referred to the number of postural changes required during AW-PP. A postural adjustment was defined as any body position change maintained for at least 5 min to alleviate discomfort, involving movements of the head, shoulders, hips, or legs. The daily number of hours under NIV or HFNO refers to the cumulative hours within a 24 h period during which the patient received either NIV or HFNO, from the initiation of therapy until the clinical outcome (escalation to invasive ventilation, intubation, or improvement and weaning from NIV or HFNO).
Adverse events were assessed as follows: kinking NIRS circuit was defined as any bending, twisting, or compression of HFNO or NIV circuit that impeded airflow. Pain assessment was conducted using the Visual Analog Scale (VAS), with a threshold of greater than 3 points for recording. If a patient presents with symptoms such as shortness of breath, difficulty breathing, or chest tightness, oxygen saturation is measured concurrently to further assess their condition. A reading below 95% is considered indicative of desaturation, which may help explain the symptoms reported by the patient. The dizziness assessment is based on a subjective scale reported by the patient, similar to a pain scale. Patients rate their dizziness from 0 to 10, with 0 indicating no dizziness and 10 indicating the most severe dizziness. Scores greater than 3 are recorded. Pressure ulcer severity is assessed according to the staging criteria established by the National Pressure Ulcer Advisory Panel (NPUAP) and the European Pressure Ulcer Advisory Panel (EPUAP) [19].
Statistical analysis
Statistical analysis was performed using SPSS Statistics, version 22.0 (SPSS Inc., Chicago, IL, USA). Continuous variables were expressed as mean ± standard deviation (SD) for normally distributed data or as medians with interquartile ranges (25th to 75th percentiles) for skewed distributions. Normality was assessed using the Kolmogorov–Smirnov test, and homogeneity of variance was evaluated with Bartlett's test. For group comparisons, the chi-square test (or Fisher's exact test when appropriate) was used for categorical data, while the unpaired t-test (or Wilcoxon rank-sum test, depending on the data distribution) was applied to continuous variables. Clinical and demographic variables were compared between the observation and control groups. A P-value of < 0.05 was considered statistically significant.
Results
We randomly assigned 76 of the 168 patients who were eligible for evaluation between February 2023 to May 2024 to either the control group (38 patients) or the observation group (38 patients) (Fig. 4). No patients lost to follow-up. The baseline characteristics were equally distributed amongst these two study groups (Table 1).
Fig. 4.
CONSORT flow diagram of randomized and analyzed participants
Table 1.
Baseline characteristics of the study participants
| control group (n = 38) | observation group (n = 38) | P | |
|---|---|---|---|
| Sex (males/females) | 22/16 | 26/12 | 0.342 |
| Age (years), mean ± SD | 61.87 ± 7.82 | 59.63 ± 8.77 | 0.286 |
| BMI (kg/m2), mean ± SD | 28.53 ± 2.54 | 27.97 ± 3.26 | 0.232 |
| Obesity (BMI ≥ 30 kg/m2), n (%) | 8 (21) | 12 (32) | 0.297 |
| Hypertension,n (%) | 17 (45) | 22 (58) | 0.251 |
| Chronic cardiovascular disease, n (%) | 17 (45) | 13 (34) | 0.348 |
| Diabetes, n (%) | 16 (42) | 11 (29) | 0.231 |
| Chronic pulmonary disease, n (%) | 4 (11) | 6 (16) | 0.497 |
| Chronic kidney disease, n (%) | 3 (8) | 2 (5) | 0.644 |
| NIRS typen,n(%) | 0.169 | ||
| HFNO | 27 (71) | 32 (84) | |
| NIV(facemask) | 11 (29) | 6 (16) | |
| Flow rate (HFNO) (%), mean ± SD | 45.00 ± 3.86 | 45.53 ± 3.64 | |
| PEEP (NIV), mean ± SD | 6.97 ± 0.82 | 7.34 ± 1.21 | 0.126 |
| FiO2 (%), mean ± SD | 67.37 ± 8.91 | 69.47 ± 7.24 | 0.262 |
| SpO2 (%), mean ± SD | 90.97 ± 2.91 | 91.39 ± 3.00 | 0.536 |
| PaO2 (kPa), mean ± SD | 8.69 ± 0.66 | 8.80 ± 0.57 | 0.451 |
| PaO2/FiO2 ratio,mean ± SD | 13.13 ± 2.05 | 12.79 ± 1.51 | 0.419 |
| SpO2/FiO2 ratio,mean ± SD | 137.28 ± 18.08 | 133.04 ± 15.48 | 0.276 |
BMI: Body mass index, NIRS non-invasive respiratory support, HFNO High-flow Nasal Oxygen, NIV Non-invasive ventilation; PEEP positive end-expiratory pressure
The observation group had shorter the daily duration spent on executing the AW-PP (2.74 ± 0.86 min vs. 4.64 ± 1.02 min, P < 0.001), longer the daily total AW-PP (8.52 ± 1.01 h vs. 6.03 ± 0.66 h, P < 0.001), longer the daily duration until the first position adjustment (59.89 ± 12.73 min vs. 36.57 ± 8.69 min, P < 0.001), and lower the daily frequency of position adjustments during the AW-PP (11.03 ± 2.67 vs. 17.95 ± 2.58, P < 0.001) in comparison with the control group (Table 2).
Table 2.
Outcomes for the study cohort
| control group (n = 38) | observation group (n = 38) | P | |
|---|---|---|---|
| Daily duration spent on executing the AW-PP (minutes), mean ± SD | 4.64 ± 1.02 | 2.74 ± 0.86 | < 0.001 |
| Daily total AW-PP (hours),mean ± SD | 6.03 ± 0.66 | 8.52 ± 1.01 | < 0.001 |
| Daily duration until the first position adjustment (minutes), mean ± SD | 36.57 ± 8.69 | 59.89 ± 12.73 | < 0.001 |
| Daily frequency of position adjustments during the AW-PP(n),mean ± SD | 17.95 ± 2.58 | 11.03 ± 2.67 | < 0.001 |
| daily number of hours under HFNO (hours),mean ± SD | 4.34 ± 1.08 | 3.88 ± 1.16 | 0.122 |
| daily number of hours under NIV (hours),mean ± SD | 4.98 ± 0.66 | 5.60 ± 1.15 | 0.175 |
| Escalated to NIV (n),% | 9 (33.3) | 7 (21.9) | 0.324 |
| Hospital LOS(days),mean ± SD | 19.13 ± 4.70 | 17.84 ± 5.97 | 0.299 |
| Intubation, n (%) | 11 (28.9) | 9 (23.7) | 0.602 |
| mortality, n (%) | 6 (15.8) | 4 (10.5) | 0.497 |
| Adverse events | |||
| Kinking NIRS circuit,n (%) | 23 (60.5) | 5 (13.2) | < 0.001 |
| Pain, n (%) | 21 (55.3) | 7 (18.4) | 0.001 |
| Shortness of breath,n (%) | 9 (23.7) | 2 (5.3) | 0.022 |
| Dizziness, n (%) | 5 (13.2) | 0 (0) | 0.021 |
| Pressure ulcers, n (%) | 26 (68.4) | 7 (18.4) | < 0.001 |
| Stage | |||
| I, n (%) | 18 (47.4) | 6 (15.8) | 0.003 |
| II, n (%) | 8 (21.1) | 1 (2.6) | 0.013 |
| Site | |||
| Face, n (%) | 12 (31.6) | 3 (7.9) | 0.009 |
| Chest, n (%) | 21 (55.3) | 5 (13.2) | < 0.001 |
| Knee, n (%) | 7 (18.4) | 1 (2.6) | 0.025 |
| Other, n (%) | 2 (5.3) | 0 (0) | 0.152 |
AW-PP awake prone positioning, HFNO High-flow Nasal Oxygen, NIV Non-invasive ventilation, LOS length of stay, NIRS non-invasive respiratory support
No significant differences in intubation rates (9 vs. 11, P = 0.602) and mortality rates (4 vs. 6, P = 0.602) were found between both groups. No significant differences in the daily number of hours under HFNO (3.88 ± 1.16 h vs.4.34 ± 1.08 h, P = 0.122), the daily number of hours under NIV (5.60 ± 1.15 h vs.4.98 ± 0.66 h, P = 0.175), escalated to NIV (7 vs. 9, P = 0.324) and hospital LOS (17.84 ± 5.97d vs.19.13 ± 4.70d, P = 0.299) were found between both groups (Table 2).
However, in terms of adverse events, the observation group showed lower kinking NIRS circuit (5 vs. 23, P < 0.001), pain (7 vs. 21, P = 0.001), shortness of breath (2 vs. 9, P = 0.022), dizziness (0 vs. 5, P = 0.021), and pressure ulcer incidence (7 vs. 26, P < 0.001) than the control group (Table 2). Especially with regards to the stage and the site of pressure ulcer, the two groups of patients had a predominance of stage I and stage II, and the observation group showed lower stage I (6 vs.18, P = 0.003) and stage II (1 vs.8, P = 0.013) than the control group. In addition, the observation group exhibited lower incidence of ulcers to the face (3 vs.12, P = 0.009), chest (5 vs.21, P < 0.001), and knees (1 vs.7, P = 0.025) in comparison with the control group (Table 2).
Discussion
This randomized controlled trial investigated the effects of innovative modular prone positioning tools on patients with ARDS induced by COVID-19 during the acute phase of AW-PP. The primary outcomes demonstrated significant improvements in patient comfort and a reduction in adverse events, including kinking NIRS circuit, pain, pressure injuries, and dizziness, in the observation group when compared to those using traditional soft pillows. However, despite these positive outcomes, no significant differences were observed between the two groups regarding intubation rates or mortality.
Prolonged use of AW-PP has been shown to improve symptoms and reduce mortality in ARDS patients with COVID-19, but it often caused discomfort and adverse effects such as pressure injuries, pain, and dizziness [35]. In clinical practice, intravenous sedatives were routinely administered during AW-PP to provide analgesia, enhance patient comfort, and minimize physical movement [40]. However, the use of prolonged or high-dose sedatives was associated with several adverse reactions, including respiratory suppression, hypotension, tachycardia, electrolyte imbalances, and cognitive decline [41].To alleviate patient discomfort and reduce the risk of adverse events such as pressure injuries and nerve damage, various prone positioning tools, including soft pillows, cushions, and frames, were employed. For example, Minnis et al. demonstrated that the Tony support system, a polyurethane foam cushion, effectively reduced the incidence of pressure marks and neuropraxias, while also minimizing the risk of orbital and maxillofacial injuries during prone positioning for spinal surgeries and chronic pain procedures [39]. Similarly, Ruhland et al. reported that polyurethane cushions applied to the thorax, pelvis, and head successfully reduced pressure injuries in ARDS patients undergoing AW-PP [42]. Additionally, Sun et al. showed that protective orbital cushions could prevent orbital compartment syndrome [43]. Despite these findings, no randomized controlled trials had specifically evaluated the efficacy of prone positioning tools in improving patient comfort and mitigating adverse events during prone ventilation. This gap in the literature highlighted the need for further investigation into the role of these tools in optimizing patient outcomes during AW-PP.
The innovative modular prone positioning tools developed in our team address key challenges associated with traditional prone positioning, such as discomfort and pressure injuries. The toolset consists of five components: a head pad, chest pad, elbow pads, knee pads, and ankle pads, each designed to enhance patient comfort and reduce complications during prolonged prone positioning, especially in ARDS patients receiving NIRS. The head pad features a U-shaped recess that evenly distributes the head's weight across the face, reducing orbital pressure and the risk of intraocular congestion. The chest pad minimizes pressure on the chest and abdomen, alleviating dyspnea and dizziness. The elbow, knee, and ankle pads provide targeted support to the extremities, preventing localized pressure injuries and promoting comfort by allowing natural positioning of the limbs. Together, these modular components reduce pressure-related complications, improve patient adherence to prone positioning, and support effective respiratory management.
The ergonomic design of the modular prone positioning tools played a pivotal role in significantly enhancing patient comfort. The results of this study indicate that patients in the observation group had a significantly longer daily total AW-PP time, a longer daily duration until the first position adjustment, and fewer daily position adjustments during the AW-PP. The innovative modular prone positioning tools, made from medium- and high-density sponge materials, were designed to align with human biomechanics, providing support for key body areas such as the head, chest, elbows, knees, and ankles. These tools enhances patient comfort through several key mechanisms. Firstly, it optimizes body positioning, ensuring proper alignment to avoid discomfort caused by misaligned posture. Secondly, the tool redistributes pressure across the body, alleviating localized stress, particularly in the chest, abdomen, and pelvis, which reduces discomfort compared to traditional prone positioning. Additionally, it improves respiratory function and circulation by preventing excessive compression of the chest and abdominal cavity. Finally, the ergonomic design minimizes strain on muscles and joints, thereby reducing physical fatigue during prolonged use. These combined features not only significantly increase patient comfort, particularly for those requiring extended prone positioning, but also reduce the physical workload for caregivers by minimizing the need for frequent repositioning.
In our study, HFNO was the initial mode of respiratory support for the majority of patients, with escalation to NIV for those experiencing persistent hypoxemia or respiratory distress. Both groups adhered to a standardized NIRS protocol, ensuring comparability, and the escalation rate from HFNO to NIV was similar between the groups. Despite this, the observation group experienced significantly fewer adverse events, including facial and chest pressure ulcers, even among patients who required NIV escalation. This suggests that the modular prone positioning tools effectively mitigated the risks typically associated with prolonged NIV, such as skin breakdown and facial injuries. While no significant differences in the daily number of hours under HFNO and NIV use were observed between the groups, the observation group had notably fewer pressure ulcers, highlighting the protective role of the modular tools in redistributing pressure and reducing the risk of skin injuries, particularly in areas vulnerable to prolonged interface contact, such as the face and chest. This finding underscores the critical role of ergonomic design in reducing pressure-related complications during prone ventilation, emphasizing the need to incorporate patient comfort and skin integrity into the management of ARDS, particularly when both HFNO and NIV are essential components of care.
Traditional prone positioning often resulted in kinking of the NIRS circuit due to pressure and misalignment, which subsequently compromised respiratory support. To address this issue, we developed an innovative modular prone positioning tools that incorporated a U-shaped headrest. This design effectively prevented face-bed contact, thereby reducing the pressure and misalignment on the NIRS circuit and minimizing the risk of kinking. Results show a significantly lower incidence of kinking NIRS circuit in the observation group compared to the control group, ensuring stable NIRS circuit alignment and improving treatment safety and efficacy. In addition, the traditional prone position is associated with a high incidence of pain, dyspnea, and dizziness, primarily due to pressure on the chest, abdomen, and joints, which impairs ventilation, circulation, and overall comfort [44]. Chest compression restricts lung expansion, contributing to breathing difficulties, while pressure on the face and neck can induce dizziness, particularly in patients with musculoskeletal or cardiovascular comorbidities [45]. Our study shows that a novel prone position device significantly reduces these complications. By redistributing body weight and improving alignment, the device alleviates pressure on critical areas, enhancing respiratory mechanics and circulation. This results in better lung expansion, reduced cardiovascular strain, and improved patient comfort. These findings suggest that this new tool can enhance patient safety and comfort during prone positioning, with potential applications in musculoskeletal and respiratory rehabilitation.
Prolonged prone positioning has been associated with improved oxygenation and reduced intubation rates [31, 36, 37]. However, no significant differences in intubation or mortality rates were observed in this study. This lack of impact on clinical outcomes may be attributed to two key factors. First, the study was primarily designed to detect differences in patient comfort during AW-PP, with a sample size calculation ensuring sufficient power (90%) for this objective, but lacking the power to detect differences in secondary outcomes like mortality and intubation, which require larger sample sizes due to their lower incidence. Second, the similar durations of NIRS modalities and the absence of substantial differences in oxygenation strategies between the groups likely limited the observed impact on primary clinical outcomes. Despite these factors, the modular prone positioning tools demonstrated significant reductions in adverse events, such as pain, dizziness, and pressure ulcers, indicating that their primary benefit lies in improving patient comfort and safety. This may enhance adherence to the prone positioning protocol, thereby mitigating complications associated with prolonged positioning. However, the tools did not directly influence the clinical trajectory of ARDS, where disease severity, comorbidities, and respiratory support strategies are more decisive in determining outcomes.
Limitations
This study represents the first attempt to evaluate the impact of innovative modular prone positioning tools on comfort and adverse effects in patients with ARDS secondary to COVID-19 during AW-PP. While the findings of this RCT suggest potential benefits for broader clinical application, several limitations must be acknowledged. First, the small sample size and single-center design may introduce biases and limit the generalizability of the results. Larger, multicenter RCTs with diverse patient populations are needed to confirm these findings and enhance external validity. Second, the study lacked a comprehensive quantitative analysis of how the tools improve comfort and reduce adverse effects. Future research should incorporate objective and multidimensional evaluations to better assess these outcomes. Third, potential confounding variables, such as baseline patient conditions and levels of caregiver assistance, were not fully controlled. Their influence on the results highlights the need for more rigorous control in subsequent studies. Finally, the study focused on short-term outcomes and did not assess long-term measures like functional recovery or quality of life, limiting the understanding of the tools' sustained benefits. Future studies should include longitudinal follow-up to capture a broader range of outcomes. In summary, while this study offers valuable initial insights, further research with larger samples, multicenter designs, and comprehensive assessments is essential to validate these findings and support the broader clinical adoption of these tools.
Conclusion
Our study demonstrated that the innovative modular prone positioning tool successfully extended the duration patients could maintain the awake prone position while significantly improving their comfort. The tool also effectively reduced adverse events such as pain, respiratory discomfort, dizziness, and pressure ulcers. However, it did not lead to significant improvements in critical clinical endpoints, such as intubation rates or mortality. These findings suggest that while the tool improves patient care during prone positioning, it does not directly influence key clinical outcomes. Future multicenter studies with larger cohorts are needed to further validate these findings and support the broader clinical implementation of the modular tools.
Supplementary Information
Author contributions
DH was primarily responsible for the study conception, oversight of clinical implementation, and the analysis of results. HT and WS coordinated the patient recruitment, clinical interventions, and data analysis. JW and ZY assisted with data collection, patient assessments, and performed statistical analysis. LX contributed to the literature review and manuscript revision. CJ, AZ and XK. provided critical guidance on the study design, supervised the research process, and played a pivotal role in the manuscript revision and final approval. All authors contributed to the interpretation of results and reviewed the final manuscript before submission.
Funding
This work was supported by the Research Launch Project of The Fourth People's Hospital Affiliated to Tongji University (Grant Number: sykyqd02001) and the Guiding Projects of Fujian Science and Technology Department (Grant number:2023Y0101).
Availability of data and materials
No datasets were generated or analysed during the current study.
Declarations
Ethics approval and consent to participate
The studies involving human participants were reviewed and approved by the Medical Ethics Committee of Shanghai Fourth People’s Hospital (No. SYLL2023008). The patients/participants provided their written informed consent to participate in this study. For the publication of any potentially identifiable photos or data in this article, the individual(s)' written informed consent has been obtained.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Dunbing Huang, Huan Tian and Wei Song have contributed equally to this work.
Contributor Information
Cai Jiang, Email: jiangcai88@126.com.
Anren Zhang, Email: anren0124@tongji.edu.cn.
Xiaohua Ke, Email: kxh22@tongji.edu.cn.
References
- 1.Schieffer E, Schieffer B, Li X. The race for ACE: targeting angiotensin-converting enzymes (ACE) in SARS-CoV-2 infection. J Renin Angiotensin Aldosterone Sys. 2022;2022:2549063. 10.1155/2022/2549063. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Sifaat M, Patel P, Sheikh R, et al. Cardiorenal disease in COVID-19 patients. J Renin Angiotensin Aldosterone Sys. 2022;2022:4640788. 10.1155/2022/4640788. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Abid A, Khan MA, Lee B, et al. Ocular distribution of the renin-angiotensin-aldosterone system in the context of the SARS-CoV-2 pandemic. J Renin Angiotensin Aldosterone Sys. 2022;2022:9970922. 10.1155/2022/9970922. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Bos LDJ, Ware LB. Acute respiratory distress syndrome: causes, pathophysiology, and phenotypes. Lancet. 2022;400:1145–56. 10.1016/S0140-6736(22)01485-4. [DOI] [PubMed] [Google Scholar]
- 5.Luoyi H, Yan P, Qihong F, et al. Relationship between angiotensin-converting enzyme insertion/deletion polymorphism and the risk of COVID-19: a meta-analysis. J Renin Angiotensin Aldosterone Sys. 2023;2023:3431612. 10.1155/2023/3431612. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Atiku SM, Kasozi D, Campbell K, et al. Single nucleotide variants (SNVs) of angiotensin-converting enzymes (ACE1 and ACE2): a plausible explanation for the global variation in COVID-19 prevalence. J Renin Angiotensin Aldosterone Sys. 2023;2023:9668008. 10.1155/2023/9668008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Meyer NJ, Gattinoni L, Calfee CS. Acute respiratory distress syndrome. Lancet. 2021;398:622–37. 10.1016/S0140-6736(21)00439-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Coppo A, Bellani G, Winterton D, et al. Feasibility and physiological effects of prone positioning in non-intubated patients with acute respiratory failure due to COVID-19 (PRON-COVID): a prospective cohort study. Lancet Respir Med. 2020;8:765–74. 10.1016/S2213-2600(20)30268-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Sansoè G, Aragno M, Anand V. New viral diseases and new possible remedies by means of the pharmacology of the renin-angiotensin system. J Renin Angiotensin Aldosterone Sys. 2023;2023:3362391. 10.1155/2023/3362391. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Henderson AC, Sá RC, Theilmann RJ, et al. The gravitational distribution of ventilation-perfusion ratio is more uniform in prone than supine posture in the normal human lung. J Appl Physiol. 1985;2013(115):313–24. 10.1152/japplphysiol.01531.2012. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Fossali T, Pavlovsky B, Ottolina D, et al. Effects of prone position on lung recruitment and ventilation-perfusion matching in patients with COVID-19 acute respiratory distress syndrome: a combined CT scan/electrical impedance tomography study. Crit Care Med. 2022;50:723–32. 10.1097/CCM.0000000000005450. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Wang Y-X, Zhong M, Dong M-H, et al. Prone positioning improves ventilation-perfusion matching assessed by electrical impedance tomography in patients with ARDS: a prospective physiological study. Crit Care. 2022;26:154. 10.1186/s13054-022-04021-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Dilken O, Rezoagli E, Yartaş Dumanlı G, et al. Effect of prone positioning on end-expiratory lung volume, strain and oxygenation change over time in COVID-19 acute respiratory distress syndrome: a prospective physiological study. Front Med. 2022;9:1056766. 10.3389/fmed.2022.1056766. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Malbouisson LM, Busch CJ, Puybasset L, et al. Role of the heart in the loss of aeration characterizing lower lobes in acute respiratory distress syndrome CT Scan ARDS Study Group. Am J Respir Crit Care Med. 2000;161:2005–12. [DOI] [PubMed] [Google Scholar]
- 15.Walter T, Ricard J-D. Extended prone positioning for intubated ARDS: a review. Crit Care. 2023;27:264. 10.1186/s13054-023-04526-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Guerin C, Baboi L, Richard JC. Mechanisms of the effects of prone positioning in acute respiratory distress syndrome. Intensive Care Med. 2014;40:1634–42. [DOI] [PubMed] [Google Scholar]
- 17.Atiku SM, Kasozi D, Campbell K, et al. Single nucleotide variants (SNVs) of angiotensin-converting enzymes (ACE1 and ACE2): a plausible explanation for the global variation in COVID-19 prevalence. J Renin Angiotensin Aldosterone Sys. 2023;2023:96680088. 10.1155/2023/9668008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Fan E, Del Sorbo L, Goligher EC, et al. An official american thoracic society/european society of intensive care medicine/society of critical care medicine clinical practice guideline: mechanical ventilation in adult patients with acute respiratory distress syndrome. Am J Respir Crit Care Med. 2017;195:1253–63. 10.1164/rccm.201703-0548ST. [DOI] [PubMed] [Google Scholar]
- 19.Cho Y-J, Moon JY, Shin E-S, et al. Clinical practice guideline of acute respiratory distress syndrome. Tuberc Respir Dis (Seoul). 2016;79:214–33. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Papazian L, Munshi L, Guérin C. Prone position in mechanically ventilated patients. Intensive Care Med. 2022;48:1062–5. 10.1007/s00134-022-06731-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Slessarev M, Cheng J, Ondrejicka M, et al. Patient self-proning with high-flow nasal cannula improves oxygenation in COVID-19 pneumonia. Can J Anaesth. 2020;67:1288–90. 10.1007/s12630-020-01661-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Li J, Luo J, Pavlov I, et al. Awake prone positioning meta-analysis group awake prone positioning for non-intubated patients with COVID-19-related acute hypoxaemic respiratory failure: a systematic review and meta-analysis. Lancet Respir Med. 2022;10:573–83. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Nasa P, Azoulay E, Khanna AK, et al. Expert consensus statements for the management of COVID-19-related acute respiratory failure using a Delphi method. Crit Care. 2021;25:106. 10.1186/s13054-021-03491-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Serpa Neto A, Checkley W, Sivakorn C, et al. Pragmatic recommendations for the management of acute respiratory failure and mechanical ventilation in patients with COVID-19 in low and middle-income countries. Am J Trop Med Hyg. 2021;104:60–71. 10.4269/ajtmh.20-0796. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Grasselli G, Calfee CS, Camporota L, et al. ESICM guidelines on acute respiratory distress syndrome: definition, phenotyping and respiratory support strategies. Intensive Care Med. 2023;49:727–59. 10.1007/s00134-023-07050-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Thompson AE, Ranard BL, Wei Y, et al. Prone positioning in awake, nonintubated patients with COVID-19 hypoxemic respiratory failure. JAMA Intern Med. 2020;180:1537–9. 10.1001/jamainternmed.2020.3030. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Elharrar X, Trigui Y, Dols A-M, et al. Use of prone positioning in nonintubated patients with COVID-19 and hypoxemic acute respiratory failure. JAMA. 2020;323:2336–8. 10.1001/jama.2022.7993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Scaravilli V, Grasselli G, Castagna L, et al. Prone positioning improves oxygenation in spontaneously breathing nonintubated patients with hypoxemic acute respiratory failure: A retrospective study. J Crit Care. 2015;30:1390–4. 10.1016/j.jcrc.2015.07.008. [DOI] [PubMed] [Google Scholar]
- 29.Ding L, Wang L, Ma W, et al. Efficacy and safety of early prone positioning combined with HFNC or NIV in moderate to severe ARDS: a multi-center prospective cohort study. Crit Care. 2020;24:28. 10.1186/s13054-020-2738-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Perez-Nieto OR, Escarraman-Martinez D, Guerrero-Gutierrez MA, et al. Awake prone positioning and oxygen therapy in patients with COVID-19: the APRONOX study. Eur Respir J. 2022;59:371. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Ehrmann S, Li J, Ibarra-Estrada M, et al. Awake prone positioning for COVID-19 acute hypoxaemic respiratory failure: a randomised, controlled, multinational, open-label meta-trial. Lancet Respir Med. 2021;9:1387–95. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Chiumello D, Chiodaroli E, Coppola S, et al. Awake prone position reduces work of breathing in patients with COVID-19 ARDS supported by CPAP. Ann Intensive Care. 2021;11:179. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Grieco DL, Delle Cese L, Menga LS, et al. Physiological effects of awake prone position in acute hypoxemic respiratory failure. Crit Care. 2023;27:315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Guérin C, Reignier J, Richard JC, et al. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med. 2023;368(23):2159–68. [DOI] [PubMed] [Google Scholar]
- 35.Cao W, He N, Luo Y, et al. Awake prone positioning for non-intubated patients with COVID-19-related acute hypoxic respiratory failure: a systematic review based on eight high-quality randomized controlled trials. BMC Infect Dis. 2023;23:415. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 36.Esperatti M, Busico M, Fuentes NA, et al. Argentine collaborative group on high flow and prone positioning. impact of exposure time in awake prone positioning on clinical outcomes of patients with COVID-19-related acute respiratory failure treated with high-flow nasal oxygen: a multicenter cohort study. Crit Care. 2022;26(1):16. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37.Ibarra-Estrada M, Li J, Pavlov I, et al. Factors for success of awake prone positioning in patients with COVID-19-induced acute hypoxemic respiratory failure: analysis of a randomized controlled trial. Crit Care. 2022;26:84. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38.Girard R, Baboi L, Ayzac L, et al. The impact of patient positioning on pressure ulcers in patients with severe ARDS: results from a multicentre randomised controlled trial on prone positioning. Intensive Care Med. 2014;40:397–403. 10.1007/s00134-013-3188-1. [DOI] [PubMed] [Google Scholar]
- 39.Minnis P, Walmsley C, Da Silva E. Evaluation of a prone support cushion for use in chronic pain procedures and prone position surgery. J Clin Anesth. 2021;72: 110307. 10.1016/j.jclinane.2021.110307. [DOI] [PubMed] [Google Scholar]
- 40.Zhang H, Tan J, Zhang H, et al. Efficacy and safety of dexmedetomidine in the prone position in elderly patients with pneumonia: a prospective, double-blind. Randomized Controll Study Lung. 2024;202:553–60. 10.1007/s00408-024-00735-w. [DOI] [PubMed] [Google Scholar]
- 41.Alwakeel M, Wang Y, Torbic H, et al. Impact of sedation practices on mortality in COVID-19-associated adult respiratory distress syndrome patients: a multicenter retrospective descriptive study. J Intensive Care Med. 2024;39:646–54. 10.1177/08850666231224395. [DOI] [PubMed] [Google Scholar]
- 42.Ruhland J, Dähnert E, Zilezinski M, et al. Pressure injury prevention in patients in prone position with acute respiratory distress syndrome and COVID-19. Crit Care Nurse. 2023;43:46–54. 10.4037/ccn2023559. [DOI] [PubMed] [Google Scholar]
- 43.Sun L, Hymowitz M, Pomeranz HD. Eye protection for patients with COVID-19 undergoing prolonged prone-position ventilation. JAMA Ophthalmol. 2021;139:109–12. 10.1001/jamaophthalmol.2020.4988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 44.Wright AD, Flynn M. Using the prone position for ventilated patients with respiratory failure: a review. Nurs Crit Care. 2011;16:19–27. 10.1111/j.1478-5153.2010.00425.x. [DOI] [PubMed] [Google Scholar]
- 45.González-Seguel F, Pinto-Concha JJ, Aranis N, et al. Adverse events of prone positioning in mechanically ventilated adults with ARDS. Respir Care. 2023;66:1898–911. 10.4187/respcare.09194. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
No datasets were generated or analysed during the current study.