Benefits and risks of manual hyperinflation in intubated and mechanically ventilated intensive care unit patients: a systematic review

Manual and ventilator hyperinflation parameters used by intensive care physiotherapists in Sri Lanka: An online survey

INTRODUCTION

Hyperinflation is a common procedure to clear secretion, increase lung compliance and enhance oxygenation in mechanically ventilated patients. Hyperinflation can be provided as manual hyperinflation (MHI) or ventilator hyperinflation (VHI), where outcomes depend upon the methods of application. Hence it is crucial to assess the application of techniques employed in Sri Lanka due to observed variations from recommended practices.

OBJECTIVE

This study is aimed to evaluate the application and parameters used for MHI and VHI by physiotherapists in intensive care units (ICUs) in Sri Lanka.

METHODOLOGY

An online survey was conducted among physiotherapists who are working in ICUs in Sri Lanka using WhatsApp groups and other social media platforms.

RESULTS

A total of 96 physiotherapists responded. The survey comprised of three sections to obtain information about socio-demographic data, MHI practices and VHI practices. Most of the respondents (47%) worked in general hospitals and 74% of participants had a bachelor's degree in physiotherapy; 31.3% had 3-6 years of experience; 93.8% used hyperinflation, and 78.9% used MHI. MHI was performed routinely and as needed to treat low oxygen levels, abnormal breath sounds, and per physician orders while avoiding contraindications. Self-inflation bags are frequently used for MHI (40.6%). Only a few participants (26%) used a manometer or tracked PIP. In addition to the supine position, some participants (37.5%) used the side-lying position. Most physiotherapists followed the recommended MHI technique: slow squeeze (57.3%), inspiratory pause (45.8%), and quick release (70.8%). VHI was practised by 19.8%, with medical approval and it was frequently performed by medical staff compared to physiotherapists. Treatment time, number of breaths, and patient positioning varied, and parameters were not well-defined.

CONCLUSION

The study found that MHI was not applied with the recommended PIP, and VHI parameters were not identified. The study indicates a need to educate physiotherapists about current VHI and MHI practice guidelines.

Nursing Practice of Airway Care Interventions and Prone Positioning in ICU Patients with COVID-19-A Dutch National Survey

Background: Airway care interventions and prone positioning are used in critically ill patients with coronavirus disease 2019 (COVID-19) admitted to the intensive care unit (ICU) to improve oxygenation and facilitate mucus removal. At the onset of the COVID-19 pandemic, the decision-making process regarding the practice of airway care interventions and prone positioning was challenging. Objective: To provide an overview of the practice of airway care interventions and prone positioning during the second wave of the pandemic in the Netherlands. Method: Web-based survey design. Seventy ICU nurses, each representing one intensive care in the Netherlands, were contacted for participation. Potential items were generated based on a literature search and formulated by a multidisciplinary team. Questions were pilot tested for face and construct validity by four intensive care nurses from four different hospitals. Results: The response rate was 53/77 (69%). This survey revealed widespread use of airway care interventions in the Netherlands in COVID-19 patients, despite questionable benefits. Additionally, prone positioning was used in invasively and non-invasively ventilated patients. Conclusions: The use of airway care interventions and prone positioning is time consuming and comes with the production of waste. Further research is needed to assess the effectiveness, workload, and environmental impact of airway care interventions and prone positioning.

Benefits and risks of ventilator hyperinflation in mechanically ventilated intensive care patients: A systematic review and meta-analysis

OBJECTIVES

Patients requiring mechanical ventilation in the intensive care unit (ICU) have diminished respiratory defences and are at high risk of respiratory compromise, leading to an increased risk of pulmonary infection and prolonged ventilation. Ventilator hyperinflation (VHI) is an airway clearance technique used by physiotherapists and is suggested to improve respiratory mechanics. The objective of this study was to review the evidence for the benefits and risks of VHI in intubated and mechanically ventilated patients in the ICU.

REVIEW METHOD USED

We conducted a systematic review.

DATA SOURCES

We searched PubMed, Embase, CINAHL, CENTRAL, and Scopus from inception to 31st May 2022 for all randomised control trials evaluating VHI in intubated and mechanically ventilated adults in the ICU.

REVIEW METHODS

Two authors independently performed study selection and data extraction. Individual study risk of bias was assessed using the Physiotherapy Evidence Database scale, and certainty in outcomes was assessed using the Grading of Recommendations, Assessment, Development and Evaluations framework.

RESULTS

We included 10 studies enrolling 394 patients. Compared to standard care, VHI had significant effects on sputum clearance (Standardise mean difference: 0.36, 95% confidence interval [CI]: 0.12 to 0.61; very low certainty), static pulmonary compliance (mean difference [MD]: 4.77, 95% CI: 2.40 to 7.14; low certainty), dynamic pulmonary compliance (MD: 1.59, 95% CI: 0.82 to 2.36; low certainty) and oxygenation (MD: 0.28, 95% CI: 0.01 to 0.55; low certainty). No significant adverse events or immediate side effects relating to VHI were reported. There is a paucity of data available on the effects of VHI on clinical outcomes including mechanical ventilation duration, ICU length of stay, and mortality.

CONCLUSIONS

Our findings suggest VHI has potential short-term respiratory benefits including increased secretion clearance, pulmonary compliance, and oxygenation, with no immediate adverse effects in intubated and mechanically ventilated ICU patients. However, there remains limited data on the longer term influence of VHI on clinical outcomes, and further research to inform clinical practice is needed.

REGISTRATION

This study is registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022341421).

Systemic and Cerebral Effects of Physiotherapy in Mechanically Ventilated Subjects

BACKGROUND

Physiotherapy may result in better functional outcomes, shorter duration of delirium, and more ventilator-free days. The effects of physiotherapy on different subpopulations of mechanically ventilated patients on respiratory and cerebral function are still unclear. We evaluated the effect of physiotherapy on systemic gas exchange and hemodynamics as well as on cerebral oxygenation and hemodynamics in mechanically ventilated subjects with and without COVID-19 pneumonia.

METHODS

This was an observational study in critically ill subjects with and without COVID-19 who underwent protocolized physiotherapy (including respiratory and rehabilitation physiotherapy) and neuromonitoring of cerebral oxygenation and hemodynamics. PaO2 /FIO2 , PaCO2 , hemodynamics (mean arterial pressure [MAP], mm Hg; heart rate, beats/min), and cerebral physiologic parameters (noninvasive intracranial pressure, cerebral perfusion pressure using transcranial Doppler, and cerebral oxygenation using near-infrared spectroscopy) were assessed before (T0) and immediately after physiotherapy (T1).

RESULTS

Thirty-one subjects were included (16 with COVID-19 and 15 without COVID-19). Physiotherapy improved PaO2 /FIO2 in the overall population (T1 = 185 [108-259] mm Hg vs T0 = 160 [97-231] mm Hg, P = .02) and in the subjects with COVID-19 (T1 = 119 [89-161] mm Hg vs T0 = 110 [81-154] mm Hg, P = .02) and decreased the PaCO2 in the COVID-19 group only (T1 = 40 [38-44] mm Hg vs T0 = 43 [38-47] mm Hg, P = .03). Physiotherapy did not affect cerebral hemodynamics, whereas increased the arterial oxygen part of hemoglobin both in the overall population (T1 = 3.1% [-1.3 to 4.9] vs T0 = 1.1% [-1.8 to 2.6], P = .007) and in the non-COVID-19 group (T1 = 3.7% [0.5-6.3] vs T0 = 0% [-2.2 to 2.8], P = .02). Heart rate was higher after physiotherapy in the overall population (T1 = 87 [75-96] beats/min vs T0 = 78 [72-92] beats/min, P = .044) and in the COVID-19 group (T1 = 87 [81-98] beats/min vs T0 = 77 [72-91] beats/min, P = .01), whereas MAP increased in the COVID-19 group only (T1 = 87 [82-83] vs T0 = 83 [76-89], P = .030).

CONCLUSIONS

Protocolized physiotherapy improved gas exchange in subjects with COVID-19, whereas it improved cerebral oxygenation in non-COVID-19 subjects.

Physiotherapy practice for hospitalized patients with COVID-19

OBJECTIVE

To identify the indications for physiotherapy and to evaluate physiotherapy practices in patients with COVID-19 admitted to the ICU (on mechanical ventilation) or to the ward (spontaneously breathing).

METHODS

An online, 50-item survey was completed by physiotherapists who had been treating hospitalized patients with COVID-19 in Brazil.

RESULTS

Of the 644 physiotherapists who initiated the survey, 488 (76%) completed it. The main reasons for indications for physiotherapy in both settings reported as "very frequently" and "frequently" both in the ICU and the ward by most respondents were oxygenation improvement (> 95%) and prevention of general complications (> 83%). Physical deconditioning was considered an infrequent indication. When compared with mobilization strategies, the use of respiratory interventions showed great variability in both work settings, and techniques considered effective were underutilized. The most frequently used respiratory techniques in the ICU were positioning (86%), alveolar recruitment (73%), and hard/brief expiratory rib cage compression (46%), whereas those in the ward were active prone positioning (90%), breathing exercises (88%), and directed/assisted cough (75%). The mobilization interventions reported by more than 75% of the respondents were sitting on the edge of the bed, active and resistive range of motion exercises, standing, ambulation, and stepping in place.

CONCLUSIONS

The least common reason for indications for physiotherapy was avoidance of deconditioning, whereas oxygenation improvement was the most frequent one. Great variability in respiratory interventions was observed when compared with mobilization therapies, and there is a clear need to standardize respiratory physiotherapy treatment for hospitalized patients with COVID-19.

Effect of positioning and expiratory rib-cage compression on atelectasis in a patient who required prolonged mechanical ventilation: a case report

BACKGROUND

Pulmonary complications can be caused by intraoperative mechanical ventilation. In particular, prolonged mechanical ventilation is associated with a high mortality rate, a risk of pulmonary complications, prolonged hospitalization, and an unfavorable discharge destination. Pre- and postoperative rehabilitation are important for the resolution of pulmonary complications in acute cases. However, there has been a lack of studies on interventions for pulmonary rehabilitation of patients with chronic pulmonary complications caused by prolonged mechanical ventilation. Accordingly, we describe the effect of pulmonary rehabilitation in such a patient.

CASE PRESENTATION

We examined a 63-year-old Japanese woman with hypoxic-ischemic encephalopathy after subarachnoid hemorrhage who required prolonged mechanical ventilation. Radiographic and computed tomographic images revealed atelectasis of the right upper lobe. In addition, this atelectasis reduced the tidal volume, minute volume, and oxygen saturation and caused an absence of breath sounds in the right upper lobe during auscultation. We aimed to ameliorate the patient's atelectasis and improve her ventilation parameters by using positioning and expiratory rib-cage compression after endotracheal suctioning. Specifically, the patient was seated in Fowler's position, and mild pressure was applied to the upper thorax during expiration, improving her inspiratory volume. Immediately, breath sounds were audible in the right upper lobe. Furthermore, resolution of the patient's atelectasis was confirmed with chest radiography performed on the same day. In addition, her ventilation parameters (tidal volume, minute volume, and oxygen saturation) improved.

CONCLUSIONS

Our results indicate that physical therapists should consider application of specific positioning and expiratory rib-cage compression in patients who exhibit atelectasis because of prolonged mechanical ventilation.

An Update on Cardiorespiratory Physiotherapy during Mechanical Ventilation

Physiotherapists are integral members of the multidisciplinary team managing critically ill adult patients. However, the scope and role of physiotherapists vary widely internationally, with physiotherapists in some countries moving away from providing early and proactive respiratory care in the intensive care unit (ICU) and focusing more on early mobilization and rehabilitation. This article provides an update of cardiorespiratory physiotherapy for patients receiving mechanical ventilation in ICU. Common and some more novel assessment tools and treatment options are described, along with the mechanisms of action of the treatment options and the evidence and physiology underpinning them. The aim is not only to summarize the current state of cardiorespiratory physiotherapy but also to provide information that will also hopefully help support clinicians to deliver personalized and optimal patient care, based on the patient's unique needs and guided by accurate interpretation of assessment findings and the current evidence. Cardiorespiratory physiotherapy plays an essential role in optimizing secretion clearance, gas exchange, lung recruitment, and aiding with weaning from mechanical ventilation in ICU. The physiotherapists' skill set and scope is likely to be further optimized and utilized in the future as the evidence base continues to grow and they get more and more integrated into the ICU multidisciplinary team, leading to improved short- and long-term patient outcomes.

Effect of manual hyperinflation on recurrent atelectasis in a ventilator-dependent C3 complete spinal cord injury patient: A case report

CLINICAL CASE

We present here the case of a ventilator-dependent 76-year-old man with C3 complete spinal cord injury (SCI) who presented with recurrent left lung atelectasis managed with manual hyperinflation (MH). Atelectasis was primarily assessed with chest X-ray (CXR). Additional monitoring included blood gas analysis, serum procalcitonin, and the Modified Borg Dyspnea Scale (MBS), as an objective measure of reported dyspnea. We found that MH successfully reversed the radiographic appearance of atelectasis after the first treatment and maintained this effect for the duration of the 2-week intervention period as well as at 2 weeks of follow-up post-intervention. Furthermore, MH decreased the patient's oxygen requirements and was associated with a decrease in serum procalcitonin. Clinically, the patient reported reduced subjective dyspnea post-MH, which was reflected as an improvement on the MBS. We conclude that MH may represent a therapeutic modality for consideration in the routine management of recurrent atelectasis in mechanically ventilated patients.

Effects of manual hyperinflation with rib cage compression and endotracheal suctioning on arterial blood gas parameters in mechanically ventilated patients at a university hospital, Egypt

Background

Manual hyperinflation and expiratory rib cage compression are methods of chest physiotherapy. They are commonly applied but their value and their early utilization managing mechanically ventilated remain questionable. The purpose of the study was to investigate the effects of manual hyperinflation with rib cage compression and endotracheal suctioning on arterial blood gas parameters in mechanically ventilated patients.

Results

Seventy mechanically ventilated patients at a teaching hospital in Egypt were assigned to the clinical trial study. The age of more than half of the studied samples ranged between 60 and 69 years with a mean age of 53.64 ± 16.44 years. Initially, the ABG parameters were assessed. Then, the patients were exposed to manual hyperinflation for 5 min and 20 min external expiratory chest compression followed by endotracheal suctioning. Later, ABG parameters were assessed again and compared to the initial one. The findings revealed significant differences in ABG parameters before and after completion of MHI and ERCC and ETT suctioning in relation to PaO2 (t = 3.892) and SaO2 (t= 5.904). Also, it showed significant improvement in PaO2 and SaO2 after the completion of interventions, while no significant differences were found in other ABG parameters. This study was registered retrospectively with an ISRCTN number 39983 on 5/6/2021.

Conclusion

Applying manual hyperinflation with rib cage compression and endotracheal suctioning improved mainly the arterial oxygenation parameters in mechanically ventilated patients despite no significant changes observed in other ABG parameters.

Manual hyperinflation in children

Manual hyperinflation is used in neonatal and pediatric intensive care units to promote expiratory flow bias, but there is no consensus on the benefits of the technique. Thus, a review that presents supporting evidence is necessary. This study aims to review the literature on the manual hyperinflation maneuver in neonatal and pediatric intensive care units to analyze the evidence for this technique in terms of the forms of application (associated with other techniques or not), its safety, the performance of manual resuscitators and the influence of the physical therapist's experience, in addition to evaluating the methodological quality of the identified articles. A search was performed in the following databases: Web of Science, ScienceDirect, PubMedⓇ, Scopus, CINAHL and SciELO. Two researchers independently selected the articles. Duplicate studies were assessed, evaluated by title and abstract and then read in full. The quality of the articles was analyzed using the PEDro scale. Six articles were included, two of which had high methodological quality. The main results provided information on the contribution of the positive end-expiratory pressure valve to increasing lung volumes and the use of chest compressions to optimize expiratory flow bias, the negative influence of operator experience on the increase in peak inspiratory flow, the performance of different manual resuscitators when used with the technique and the safety of application in terms of maintaining hemodynamic stability and increasing peripheral oxygen saturation. The available studies point to a positive effect of the manual hyperinflation maneuver in children who are admitted to intensive care units. Registration PROSPERO: CRD42018108056.

Airway Care Interventions for Invasively Ventilated Critically Ill Adults-A Dutch National Survey

Airway care interventions may prevent accumulation of airway secretions and promote their evacuation, but evidence is scarce. Interventions include heated humidification, nebulization of mucolytics and/or bronchodilators, manual hyperinflation and use of mechanical insufflation-exsufflation (MI-E). Our aim is to identify current airway care practices for invasively ventilated patients in intensive care units (ICU) in the Netherlands. A self–administered web-based survey was sent to a single pre–appointed representative of all ICUs in the Netherlands. Response rate was 85% (72 ICUs). We found substantial heterogeneity in the intensity and combinations of airway care interventions used. Most (81%) ICUs reported using heated humidification as a routine prophylactic intervention. All (100%) responding ICUs used nebulized mucolytics and/or bronchodilators; however, only 43% ICUs reported nebulization as a routine prophylactic intervention. Most (81%) ICUs used manual hyperinflation, although only initiated with a clinical indication like difficult oxygenation. Few (22%) ICUs used MI-E for invasively ventilated patients. Use was always based on the indication of insufficient cough strength or as a continuation of home use. In the Netherlands, use of routine prophylactic airway care interventions is common despite evidence of no benefit. There is an urgent need for evidence of the benefit of these interventions to inform evidence-based guidelines.

Alveolar Recruitment Maneuver Reduces Cerebral Oxygen Saturation and Cerebral Blood Flow Velocity in Patients During Carotid Endarterectomy

BACKGROUND This study aimed to determine the effects of alveolar recruitment maneuver (RM) on cerebral oxygen saturation and cerebral blood velocity in patients undergoing carotid endarterectomy (CEA) before clamping of the carotid artery. MATERIAL AND METHODS In this crossover exploratory study, all patients were randomized to undergo an RM (30 cmH₂O of continuous airway pressure for 30 s) and a "sham" maneuver (SM; 5 cmH₂O for 30 s), followed by an alternative intervention after a 5-min equilibration period. Near-infrared spectroscopy (NIRS) was used to monitor regional cerebral oxygen saturation (rSO₂), and transcranial Doppler ultrasonography (TCD) to evaluate blood velocity of the middle cerebral artery (V-MCA). Changes in rSO₂, V-MCA, mean arterial pressure (MAP), and heart rate (HR) in response to the 2 interventions were compared. RESULTS A total of 59 patients underwent the study procedure. RM reduced rSO₂, V-MCA, MAP, and HR, but these variables slightly changed during SM. A significant drop in rSO₂ was observed immediately after RM compared with the baseline value (68.51±4.4% vs 64.12±5.15%; P<0.001). The decrease in rSO₂ was higher during the RM than during the SM (-6±4% vs 1±2%; P<0.001). Similarly, change in V-MCA was more significant in response to RM than SM (-26±19% vs 19±16%; P<0.001). The V-MCA value changed from 39 cm/s to 29 cm/s after RM. In addition, V-MCA of the ipsilateral to the surgical side decreased more obviously than the contralateral side (-26±19% vs -20±17%; P=0.001). CONCLUSIONS An RM at 30 cmH₂O of continuous airway pressure for 30 s decreased rSO₂ and V-MCA. In addition, MAP and HR were affected.

Efficacy of Respiratory Physiotherapy Interventions for Intubated and Mechanically Ventilated Adults with Pneumonia: A Systematic Review and Meta-Analysis

Purpose: A systematic review was conducted to investigate the effect of respiratory physiotherapy on mortality, quality of life, functional recovery, intensive care length of stay, duration of ventilation, oxygenation, secretion clearance, and pulmonary mechanics for invasively ventilated adults with pneumonia. Method: Five databases were searched for randomized trials published between January 1995 and November 2018. Study quality was assessed using a standardized Joanna Briggs Institute critical appraisal tool, and Review Manager software was used to pool the studies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to evaluate the level of certainty of the evidence. Results: A total of 14 studies of moderate quality included 251 subjects with pneumonia. Eight studies were pooled for meta-analysis. Interventions that increased inspiratory volume appeared to benefit secretion clearance by nearly 2 grams (mean difference [MD] 1.97; 95% CI: 0.80, 3.14; very low GRADE evidence) and increase static lung compliance immediately after treatment by more than 5 millilitres/centimetre H20 (MD 5.40 mL/cm H2O; 95% CI: 2.37, 8.43; very low GRADE evidence) or by more than 6 millilitres/centimetre H2O after a 20- to 30-minute delay (MD 6.86 mL/cm H2O; 95% CI: 2.86, 10.86; very low GRADE evidence). No adverse events were found. Conclusions: Respiratory physiotherapy that increases tidal volume may benefit secretion clearance and lung compliance in invasively ventilated adults with pneumonia, but its impact on other outcomes, including mortality, length of stay, and other patient-centred outcomes, is unclear, and further research is required.

Efficacy of manual hyperinflation on arterial blood gases in patients with ventilator-associated pneumonia

Background

Tracheal intubation exposes mechanically ventilated patients to serious pulmonary complications such as ventilator-associated pneumonia (VAP). This study was conducted to compare the efficacy of manual hyperinflation in supine versus lateral decubitus position on arterial blood gases (ABG) in patients with VAP. Forty-two patients with ventilator-associated pneumonia with age range from 40 to 60 years were selected. They were randomly divided into two equal groups: group A who received manual hyperinflation from supine position and group B who received manual hyperinflation from lateral decubitus position (upper most affected). Both groups received respiratory physiotherapy. The patients received 2 sessions per day for 6 days. Outcome measures were arterial blood gases (PaO₂, PaCO₂, PaO₂/FiO₂, and SaO₂). They were assessed before the 1st morning session (pre), at day 3 (post 1), and at day 6 (post 2).

Results

After sessions, significant changes of measured variables (PaO₂, PaCO₂, PaO₂/FiO₂, and SaO₂) were obtained in both groups (P < 0.05, in all variables) and by comparison between groups post-intervention; a significant difference was observed between both groups in measures of oxygenation in favor of group B (P < 0.05), whereas there was a non-significant difference in the PaC02 between both groups (post 1 P = 0.52 and post 2 P = 0.33).

Conclusion

It was concluded that effect of the bag squeezing on arterial blood gases in patients with ventilator-associated pneumonia from lateral decubitus position was more effective than from supine position.

Trial registration

PACTR, PACTR201909817075549. Registered October 21, 2018—retrospectively registered

https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=4655

Physical Therapy and Rehabilitation in Chronic Obstructive Pulmonary Disease Patients Admitted to the Intensive Care Unit

Chronic obstructive pulmonary disease (COPD) is a progressive lung condition that affects a person's ability to exercise and undertake normal physical function due to breathlessness, poor physical fitness, and muscle fatigue. Patients with COPD often experience exacerbations due to pulmonary infections, which result in worsening of their symptoms, more loss of function, and often require hospital treatment or in severe cases admission to intensive care units. Recovery from such exacerbations is often slow, and some patients never fully return to their previous level of activity. This can lead to permanent disability and premature death.Physical therapists play a key role in the respiratory management and rehabilitation of patients admitted to intensive care following acute exacerbation of COPD. This article discusses the key considerations for respiratory management of patients requiring invasive mechanical ventilation, providing an evidence-based summary of commonly used interventions. It will also explore the evidence to support the introduction of early and structured programs of rehabilitation to support recovery in both the short and the long term, as well as active mobilization, which includes strategies to minimize or prevent physical loss through early retraining of both peripheral and respiratory muscles.

A Review on Cough Augmentation Techniques: Assisted Inspiration, Assisted Expiration and Their Combination

Cough is an important mechanism of airway clearance. In patients who present weak and ineffective cough, augmentation techniques aim to assist or simulate the maneuver. These techniques target different phases of the cough cycle, mainly the inspiratory and expiratory phases, through assisted inspiration, assisted expiration and their combination. They include the manual hyperinflation, ventilator hyperinflation, glossopharyngeal breathing, manually assisted cough and mechanical insufflator-exsufflator, each applied individually or in different combinations. The aim of this review is to investigate the effectiveness and safety of cough augmentation techniques. Findings support that all commonly used techniques can theoretically improve airway clearance, as they generate higher cough peak flows compared to unassisted cough. Still, the studies assessing cough augmentation present considerable limitations and the direct comparison of different techniques is challenging. Current evidence indicate that cough peak flow shows higher increase with the combination of assisted inspiration and expiration, and improvement is greater in patients with lower unassisted values. Associated adverse events are infrequent.

Acute effects of ventilator hyperinflation with increased inspiratory time on respiratory mechanics: randomized crossover clinical trial

Objective

To evaluate the effects of ventilator hyperinflation on respiratory mechanics.

Methods

A randomized crossover clinical trial was conducted with 38 mechanically ventilated patients with pulmonary infection. The order of the hyperinflation and control (without changes in the parameters) conditions was randomized. Hyperinflation was performed for 5 minutes in pressure-controlled ventilation mode, with progressive increases of 5cmH₂O until a maximum pressure of 35cmH₂O was reached, maintaining positive end expiratory pressure. After 35cmH₂O was reached, the inspiratory time and respiratory rate were adjusted so that the inspiratory and expiratory flows reached baseline levels. Measurements of static compliance, total resistance and airway resistance, and peak expiratory flow were evaluated before the technique, immediately after the technique and after aspiration. Two-way analysis of variance for repeated measures was used with Tukey's post hoc test, and p < 0.05 was considered significant.

Results

Ventilator hyperinflation increased static compliance, which remained at the same level after aspiration (46.2 ± 14.8 versus 52.0 ± 14.9 versus 52.3 ± 16.0mL/cmH₂O; p < 0.001). There was a transient increase in airway resistance (6.6 ± 3.6 versus 8.0 ± 5.5 versus 6.6 ± 3.5cmH₂O/Ls^-1; p < 0.001) and a transient reduction in peak expiratory flow (32.0 ± 16.0 versus 29.8 ± 14.8 versus 32.1 ± 15.3Lpm; p <0.05) immediately after the technique; these values returned to pretechnique levels after tracheal aspiration. There were no changes in the control condition, nor were hemodynamic alterations observed.

Conclusion

Ventilator hyperinflation promoted increased compliance associated with a transient increase in airway resistance and peak expiratory flow, with reduction after aspiration.

Effect of inspiratory rise time on sputum movement during ventilator hyperinflation in a test lung model

OBJECTIVES

Physiotherapists may use ventilator hyperinflation to enhance secretion clearance for intubated patients. This study investigated the effects of altering percentage inspiratory rise time (IRT) on sputum movement, ratio of peak inspiratory to expiratory flow rate (PIF:PEF ratio) and net peak expiratory flow (PEF) during ventilator hyperinflation in a test lung model.

DESIGN

Laboratory-based bench study.

INTERVENTIONS

Simulated sputum (two viscosities) was inserted into clean, clear tubing and connected between a ventilator and a resuscitation bag. Thirty-six ventilator hyperinflation breaths were applied for each 5% incremental increase in IRT between 0% and 20%.

MAIN OUTCOME MEASURES

The primary outcome was sputum displacement (cm). Secondary outcomes included PIF:PEF ratio and net PEF.

RESULTS

Significant cephalad sputum movement of 2.42cm (1.59 to 3.94) occurred with IRT between 5% and 20%, compared with caudad movement of 0.53 cm (0.31 to 1.53) at 0% IRT (median sputum movement difference 3.7cm, 95% confidence interval 2.2 to 4.8, P<0.001). Incremental increases in IRT percentage produced linear enhancements in PIF:PEF ratio and net PEF for both sputum concentrations (P<0.001). However, once the critical threshold for PIF:PEF ratio of 0.9 was achieved, the distance of sputum movement remained consistent for all IRT values exceeding 5%.

CONCLUSIONS

Significant increases in sputum movement occurred when IRT percentage was lengthened to achieve the optimal PIF:PEF ratio, irrespective of sputum viscosity. This provides a theoretical rationale for therapists to consider this technique when treating mechanically ventilated patients. As no additional sputum movement was seen beyond the critical PIF:PEF ratio threshold, a low IRT percentage may potentially be used to achieve effective sputum movement.

A comparison of the effects of manual hyperinflation and ventilator hyperinflation on restoring end-expiratory lung volume after endotracheal suctioning: A pilot physiologic study

PURPOSE

Endotracheal suctioning (ES) of mechanically ventilated patients decreases end-expiratory lung volume (EELV). Manual hyperinflation (MHI) and ventilator hyperinflation (VHI) may restore EELV post-ES but it remains unknown which method is most effective. The primary aim was to compare the efficacy of MHI and VHI in restoring EELV post-ES.

MATERIALS AND METHODS

ES was performed on mechanically ventilated intensive care patients, followed by MHI or VHI, in a randomised crossover design. The washout period between interventions was 1 h. End-expiratory lung impedance (EELI), measured by electrical impedance tomography, was recorded at baseline, during ES, during hyperinflation and 1, 5, 15 and 30 min post-hyperinflation.

RESULTS

Nine participants were studied. ES decreased EELI by 1672z (95% CI, 1204 to 2140) from baseline. From baseline, MHI increased EELI by 1154z (95% CI, 977 to 1330) while VHI increased EELI by 769z (95% CI, 457 to 1080). Five minutes post-VHI, EELI remained 528z (95% CI, 4 to 1053) above baseline. Fifteen minutes post-MHI, EELI remained 351z (95% CI, 111 to 592) above baseline. At subsequent time-points, EELI returned to baseline.

CONCLUSIONS

MHI and VHI effectively restore EELV above baseline post-ES and should be considered post suctioning.

Selecting the best ventilator hyperinflation technique based on physiologic markers: A randomized controlled crossover study

BACKGROUND

Ventilator hyperinflation (VHI) is effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated subjects; however, there are no recommendations for the best ventilator settings to perform the technique.

OBJECTIVE

To compare six modes of VHI, concerning physiological markers of efficacy and safety criteria to support the selection of optimal settings.

METHODS

Thirty mechanically ventilated patients underwent six modes of VHI in a randomized order. The delivered volume, expiratory flow bias criteria, overdistension, patient-ventilator asynchronies and hemodynamic variables were assessed during the interventions.

RESULTS

Volume-controlled ventilation with inspiratory flow of 20 lpm (VC-CMV20) and pressure support ventilation (PSV) achieved the best effectiveness scores (P < 0.05). The target peak pressure of 40 cmH₂O was associated with a high incidence of overdistension. PSV showed a lower incidence of patient-ventilator asynchronies.

CONCLUSIONS

The modes VC-CMV20 and PSV are the most effective for VHI. Alveolar overdistension and patient-ventilator asynchronies must be considered when applying VHI.

Multimodality respiratory physiotherapy reduces mortality but may not prevent ventilator-associated pneumonia or reduce length of stay in the intensive care unit: a systematic review

QUESTION

In intubated adult patients receiving mechanical ventilation, does multimodality respiratory physiotherapy prevent ventilator-associated pneumonia, shorten length of intensive care unit (ICU) stay, and reduce mortality?

DESIGN

A systematic review with meta-analysis of randomised controlled trials.

PARTICIPANTS

Intubated adult patients undergoing mechanical ventilation who were admitted to an intensive care unit.

INTERVENTION

More than two respiratory physiotherapy techniques such as positioning or postural drainage, manual hyperinflation, vibration, rib springing, and suctioning.

OUTCOMES MEASURES

Incidence of ventilator-associated pneumonia (VAP), duration of ICU stay, and mortality.

RESULTS

Five trials were included in the meta-analysis. Random-effects models were used to calculate pooled weighted mean difference (WMD) for length of ICU stay and pooled risk ratio (RR) for incidence of VAP, and fixed-effects model was used to calculate pooled RR for mortality. The effect on the incidence of VAP was unclear (RR 0.73 in favour of multimodality respiratory physiotherapy, 95% CI 0.38 to 1.07). The effect on length of stay was also unclear (WMD -0.33days shorter with multimodality respiratory physiotherapy, 95% CI -2.31 to 1.66). However, multimodality respiratory physiotherapy significantly reduced mortality (RR 0.75, 95% CI 0.58 to 0.92).

CONCLUSION

Multimodality respiratory physiotherapy appeared to reduce mortality in ICU patients. It was unclear whether this occurred via a reduction in the incidence of VAP and/or length of stay because the available data provided very imprecise estimates of the effect of multimodality respiratory physiotherapy on these outcomes. These very imprecise estimates include the possibility of very worthwhile effects on VAP incidence and length of ICU stay; therefore, these outcomes should be the focus of further investigation in rigorous trials.

REGISTRATION

PROSPERO CRD42018094202. [Pozuelo-Carrascosa DP, Torres-Costoso A, Alvarez-Bueno C, Cavero-Redondo I, López Muñoz P, Martínez-Vizcaíno V (2018) Multimodality respiratory physiotherapy reduces mortality but may not prevent ventilator-associated pneumonia or reduce length of stay in the intensive care unit: a systematic review. Journal of Physiotherapy 64: 222-228].

Effects of manual hyperinflation, clinical practice versus expert recommendation, on displacement of mucus simulant: A laboratory study

Introduction

Manual hyperinflation (MH), a maneuver applied in mechanically ventilated patients to facilitate secretion removal, has large variation in its performance. Effectiveness of MH is usually evaluated by its capacity to generate an expiratory flow bias. The aim of this study was to compare the effects of MH—and its resulting flow bias—applied according to clinical practice versus according to expert recommendation on mucus movement in a lung model simulating a mechanically ventilated patient.

Methods

Twelve physiotherapists were asked to apply MH, using a self-inflating manual resuscitator, to a test lung as if to remove secretions under two conditions: according to their usual clinical practice (pre-instruction phase) and after verbal instruction to perform MH according to expert recommendation was given (post-instruction phase). Mucus simulant movement was measured with a photodensitometric technique. Peak inspiratory flow (PIF), peak inspiratory pressure (P_IP), inspiratory time (T_INSP), tidal volume (V_T) and peak expiratory flow (PEF) were measured continuously.

Results

It was found that MH performed post-instruction delivered a smaller V_T (643.1 ± 57.8 ml) at a lower P_IP (15.0 ± 1.5 cmH₂O), lower PIF (38.0 ± 9.6 L/min), longer T_INSP (1.84 ±0.54 s) and lower PEF (65.4 ± 6.7L/min) compared to MH pre-instruction. In the pre-instruction phase, MH resulted in a mean PIF/PEF ratio of 1.73 ± 0.38 and mean PEF-PIF difference of -54.6 ± 28.3 L/min, both out of the range for secretion removal. In the post-instruction phase both indexes were in the adequate range. Consequently, the mucus simulant was moved outward when MH was applied according to expert recommendation and towards the test lung when it was applied according to clinical practice.

Conclusions

Performance of MH during clinical practice with PIF higher than PEF was ineffective to clear secretion in a lung model simulating a mechanically ventilated patient. In order to remove secretion, MH should result in an adequate expiratory flow bias.

A survey of clinicians regarding respiratory physiotherapy intervention for intubated and mechanically ventilated patients with community-acquired pneumonia. What is current practice in Australian ICUs?

RATIONALE, AIMS, AND OBJECTIVES

Community-acquired pneumonia (CAP) is a common cause for intensive care unit (ICU) admission resulting in high morbidity and mortality. There is a paucity of evidence regarding respiratory physiotherapy for intubated and mechanically ventilated patients with CAP, and anecdotally clinical practice is variable in this cohort. The aims of this study were to identify the degree of variability in physiotherapy practice for intubated adult patients with CAP and to explore ICU physiotherapist perceptions of current practice for this cohort and factors that influence physiotherapy treatment mode, duration, and frequency.

METHOD

A survey was developed based on common aspects of assessment, clinical rationale, and intervention for intubated and mechanically ventilated patients. Senior ICU physiotherapists across 88 Australian public and private hospitals were recruited.

RESULTS

The response rate was 72%. Respondents (n = 75) stated their main rationale for providing a respiratory intervention were improved airway clearance (98%, n = 60/61), alveolar recruitment (74%, n = 45/61), and gas exchange (33%, n = 20/61). Respondents estimated that average intervention lasted between 16 and 30 minutes (70% of respondents, n = 41/59) and would be delivered once (44%) or twice (44%) daily. Results indicated large variability in reported practice; however, trends existed regarding positioning in alternate side-lying (81%, n = 52/64) or affected lung uppermost (83%, n = 53/64) and use of hyperinflation techniques (81%, 52/64). Decisions regarding duration were reported to be based on sputum volume (95%), viscosity (93%) and purulence (88%), cough effectiveness (95%), chest X-ray (87%), and auscultation (84%). Sixty percent reported that workload and staffing affected intervention duration and frequency. Intervention time was more likely increased when there was greater staffing (P = .03).

CONCLUSION

Respiratory physiotherapy treatment varies for intubated patients with CAP. Further research is required to determine what is considered best practice for this patient population.

Manual ventilation and open suction procedures contribute to negative pressures in a mechanical lung model

INTRODUCTION

Removal of pulmonary secretions in mechanically ventilated patients usually requires suction with closed catheter systems or flexible bronchoscopes. Manual ventilation is occasionally performed during such procedures if clinicians suspect inadequate ventilation. Suctioning can also be performed with the ventilator entirely disconnected from the endotracheal tube (ETT). The aim of this study was to investigate if these two procedures generate negative airway pressures, which may contribute to atelectasis.

METHODS

The effects of device insertion and suctioning in ETTs were examined in a mechanical lung model with a pressure transducer inserted distal to ETTs of 9 mm, 8 mm and 7 mm internal diameter (ID). A 16 Fr bronchoscope and 12, 14 and 16 Fr suction catheters were used at two different vacuum levels during manual ventilation and with the ETTs disconnected.

RESULTS

During manual ventilation with ETTs of 9 mm, 8 mm and 7 mm ID, and bronchoscopic suctioning at moderate suction level, peak pressure (P_PEAK) dropped from 23, 22 and 24.5 cm H₂O to 16, 16 and 15 cm H₂O, respectively. Maximum suction reduced P_PEAK to 20, 17 and 11 cm H₂O, respectively, and the end-expiratory pressure fell from 5, 5.5 and 4.5 cm H₂O to -2, -6 and -17 cm H₂O. Suctioning through disconnected ETTs (open suction procedure) gave negative model airway pressures throughout the duration of the procedures.

CONCLUSIONS

Manual ventilation and open suction procedures induce negative end-expiratory pressure during endotracheal suctioning, which may have clinical implications in patients who need high PEEP (positive end-expiratory pressure).

Chest physiotherapy in mechanically ventilated patients without pneumonia-a narrative review

A beneficial adjuvant role of chest physiotherapy (CPT) to promote airway clearance, alveolar recruitment, and ventilation/perfusion matching in mechanically ventilated (MV) patients with pneumonia or relapsing lung atelectasis is commonly accepted. However, doubt prevails regarding the usefulness of applying routine CPT in MV subjects with no such lung diseases. In-depth narrative review based on a literature search for prospective randomized trials comparing CPT with a non-CPT strategy in adult patients ventilated for at least 48 h. Six relevant studies were identified. Sample size was small. Various CPT modalities were used including body positioning, manual chest manipulation (mobilization, percussion, vibration, and compression), and specific techniques such as lung hyperinflation and intrapulmonary percussion. Control subjects mostly received general nursing care and tracheal suction. In general, CPT was safe and supportive, yet had debatable or no significant impact on any relevant patient outcome parameter, including pneumonia. Current evidence does not support "prophylactic" CPT in adult MV patients without pneumonia.

Lung hyperinflation by mechanical ventilation versus isolated tracheal aspiration in the bronchial hygiene of patients undergoing mechanical ventilation

OBJECTIVE

To determine the efficacy of lung hyperinflation maneuvers via a mechanical ventilator compared to isolated tracheal aspiration for removing secretions, normalizing hemodynamics and improving lung mechanics in patients on mechanical ventilation.

METHODS

This was a randomized crossover clinical trial including patients admitted to the intensive care unit and on mechanical ventilation for more than 48 hours. Patients were randomized to receive either isolated tracheal aspiration (Control Group) or lung hyperinflation by mechanical ventilator (MVH Group). Hemodynamic and mechanical respiratory parameters were measured along with the amount of aspirated secretions.

RESULTS

A total of 50 patients were included. The mean age of the patients was 44.7 ± 21.6 years, and 31 were male. Compared to the Control Group, the MVH Group showed greater aspirated secretion amount (3.9g versus 6.4g, p = 0.0001), variation in mean dynamic compliance (-1.3 ± 2.3 versus -2.9 ± 2.3; p = 0.008), and expired tidal volume (-0.7 ± 0.0 versus -54.1 ± 38.8, p = 0.0001) as well as a significant decrease in peak inspiratory pressure (0.2 ± 0.1 versus 2.5 ± 0.1; p = 0.001).

CONCLUSION

In the studied sample, the MVH technique led to a greater amount of aspirated secretions, significant increases in dynamic compliance and expired tidal volume and a significant reduction in peak inspiratory pressure.

Effect of Inspiratory Time and Lung Compliance on Flow Bias Generated During Manual Hyperinflation: A Bench Study

BACKGROUND

Manual hyperinflation can be used to assist mucus clearance in intubated patients. The technique's effectiveness to move mucus is underpinned by its ability to generate flow bias in the direction of expiration, and this must exceed specific thresholds. It is unclear whether the inspiratory times commonly used by physiotherapists generate sufficient expiratory flow bias based on previously published thresholds and whether factors such as lung compliance affect this.

METHODS

In a series of laboratory experiments, we applied manual hyperinflation to a bench model to examine the role of 3 target inspiratory times and 2 lung compliance settings on 3 measures of expiratory flow bias.

RESULTS

Longer inspiratory times and lower lung compliances were associated with improvements in all measures of expiratory flow bias. In normal compliance lungs, achievement of the expiratory flow bias thresholds were (1) never achieved with an inspiratory time of 1 s, (2) rarely achieved with an inspiratory time of 2 s, and (3) commonly achieved with an inspiratory time of 3 s. In lower compliance lungs, achievement of the expiratory flow bias thresholds was (1) rarely achieved with an inspiratory time of 1 s, (2) sometimes achieved with an inspiratory time of 2 s, and (3) nearly always achieved with an inspiratory time of 3 s. Peak inspiratory pressures exceeded 40 cm H2O in normal compliance lungs with inspiratory times of 1 s and in lower compliance lungs with inspiratory times of 1 and 2 s.

CONCLUSIONS

Inspiratory times of at least 3 s with normal compliance lungs and at least 2 s with lower compliance lungs appear necessary to achieve expiratory flow bias thresholds during manual hyperinflation. Inspiratory times shorter than this may lead to excessive peak inspiratory pressures. Verification of these findings in relation to the movement of mucus should be examined in further bench or animal models and/or human clinical trials.

Hyperinflation deteriorates arterial oxygenation and lung injury in a rabbit model of ARDS with repeated open endotracheal suctioning

Background

Hyperinflation (HI) is performed following open endotracheal suctioning (OES), whose goals include: to stimulate a cough, recover oxygenation and improve compliance. However, it may also induce unintended consequences, including: lung stress and strain, failure to maintain high distending pressure, and subsequently cycling recruitment and derecruitment. Here, our aim was to investigate the effects of hyperinflation after repeated OES on sequential alteration of arterial oxygenation and lung injury profile using a saline lavage-induced surfactant depleted ARDS rabbit model.

Methods

Briefly, 30 Japanese White Rabbits were anesthetized and ventilated in pressure-controlled setting with a tidal volume of 6-8 ml/kg. Animals were divided into four groups, i.e.; Control, ARDS, OES, and HI. Saline-lavage-induced lung injury was induced except for Control group. Thereafter, rabbits were ventilated with positive-end expiratory pressure (PEEP) at 10 cm H₂O. The ARDS group received ventilation with the same PEEP without derecruitment. As intervention, OES and HI were performed in ARDS animals. OES was performed for 15 seconds at 150 mm Hg, whereas HI was performed with PEEP at 0 cm H₂O and peak inspiratory pressure at +5 cm H₂O for a minute. Total duration of the experiment was for 3 hours. OES and HI were performed every 15 minutes from beginning of the protocol.

Results

PaO₂ was maintained at about 400 mm Hg in both control and ARDS groups for the duration of this study, while in both OES and HI groups, PaO₂ decreased continuously up to 3 hours, dropped to a mean (±SD) of 226 ± 28.9 and 97.0 ± 30.7 mmHg at 3 h, respectively. HI group had the lowest PaO₂ in the present investigation. Histological lung injury score was the highest in HI group than other three groups. Pulmonary TNF-α and IL-8 levels were the highest in HI group compared to other groups, but without significant alterations at circulatory level in all the experimental groups.

Conclusions

We show in the present study that hyperinflation following repeated OES deteriorate arterial oxygenation and the severity of lung injury in a rabbit model of ARDS undergoing mechanical ventilation.

The effect of mechanical ventilator settings during ventilator hyperinflation techniques: a bench-top analysis

Ventilator hyperinflations are used by physiotherapists for the purpose of airway clearance in intensive care. There is limited data to guide the selection of mechanical ventilator modes and settings that may achieve desired flow patterns for ventilator hyperinflation. A mechanical ventilator was connected to two lung simulators and a respiratory mechanics monitor. Peak inspiratory (PIFR) and expiratory flow rates (PEFR) were measured during manipulation of ventilator modes (pressure support ventilation [PSV], volume-controlled synchronised intermittent mandatory ventilation [VC-SIMV] and pressure-controlled synchronised intermittent mandatory ventilation [PC-SIMV]) and ventilator settings (including set tidal volume, positive end-expiratory pressure, inspiratory flow rate, inspiratory pause, pressure support, inspiratory time and/or inflation pressure). Additionally, each trial was conducted with high (0.05 l/cmH2O) and low (0.01 l/cmH2O) compliance settings on the lung simulators. Each trial was dichotomised into success or failure under three categories (attainment of PIFR-PEFR less than or equal to 0.9, PEFR/PIFR greater than 17 l/min, PEFR greater than or equal to 40 l/min). A total of 232 trials were conducted (96 VC-SIMV, 96 PC-SIMV, 40 PSV). A greater proportion of VC-SIMV trials were ceased due to high peak inspiratory pressures (35%). However, VC-SIMV trials were more likely to be successful at meeting all three outcome measures (26 VC-SIMV trials, 7 PC-SIMV trials, 0 PSV trials). It was found that manipulation of settings in VC-SIMV mode appears more successful than PSV and PC-SIMV for ventilator hyperinflations.

Clinical effects of specialist and on-call respiratory physiotherapy treatments in mechanically ventilated children: A randomised crossover trial

OBJECTIVES

The study investigated treatment outcomes when respiratory physiotherapy was delivered by non-respiratory on-call physiotherapists, compared with specialist respiratory physiotherapists.

DESIGN

Prospective, randomised crossover trial.

SETTING

Paediatric, tertiary care hospital in the United Kingdom.

PARTICIPANTS

Mechanically ventilated children requiring two physiotherapy interventions during a single day were eligible. Twenty two physiotherapists (10 non-respiratory) and 93 patients were recruited.

INTERVENTIONS

Patients received one treatment from a non-respiratory physiotherapist and another from a respiratory physiotherapist, in a randomised order. Treatments were individualised to the patients' needs, often including re-positioning followed by manual lung inflations, chest wall vibrations and endotracheal suction.

MAIN OUTCOME MEASURES

The primary outcome was respiratory compliance. Secondary outcomes included adverse physiological events and clinically important respiratory changes (according to an a priori definition).

RESULTS

Treatments delivered to 63 patients were analysed. There were significant improvements to respiratory compliance (mean increase [95% confidence intervals], 0.07 and 0.08ml·cmH2O(-1)·kg(-1) [0.01 to 0.14 and 0.04 to 0.13], p<0.01, for on-call and respiratory physiotherapists' treatments respectively). Case-by-case, there were fewer clinically important improvements following non-respiratory physiotherapists' treatments compared with the respiratory physiotherapists' (n=27 [43%] versus n=40 [63%], p=0.03). Eleven adverse events occurred, eight following non-respiratory physiotherapists' treatments.

CONCLUSIONS

Significant disparities exist in treatment outcomes when patients are treated by non-respiratory on-call physiotherapists, compared with specialist respiratory physiotherapists. There is an urgent need for targeted training strategies, or alternative service delivery models, to be explored. This should aim to address the quality of respiratory physiotherapy services, both during and outside of normal working hours.

CLINICAL TRIAL REGISTRATION NUMBER

Clinicaltrials.gov, NCT01999426.

Guideline implementation powered by feedback and education improves manual hyperinflation performance

AIM

To determine whether a literature-based guideline, powered by educational meetings and individual feedback, improves manual hyperinflation (MH) performance by intensive care unit (ICU) nurses.

BACKGROUND

MH is frequently applied in intubated and mechanically ventilated ICU patients. MH is a complex intervention, and large variation in its performance has been found.

MATERIALS AND METHODS

First, a literature-based guideline on MH was developed. The intervention consisted of education of this guideline and individual feedback. Before and 3 months after the intervention, ICU nurses performed MH maneuvers in a skills laboratory. Data collected included applied volumes, peak inspiratory flows (PIF) and peak expiratory flows (PEF), and the use of inspiratory holds.

RESULTS

Eighty nurses participated. Decrease of PIF was not statistically significant. PEF increased from 52 ± 7 to 83 ± 23 L/min (P < 0·01). PIF to PEF ratio decreased from 1·4 [1·1-1·7] to 0·8 [0·6-1·1] (P < 0·01). Peak inspiratory pressures decreased from 40 ± 14 to 19 ± 6 cm H2 O (P < 0·01). The proportion of nurses applying inspiratory holds increased from 14% to 58%; use of rapid release of the resuscitation bag, considered mandatory, increased from 4% to 61%.

CONCLUSION

Implementation of a literature-based guideline on MH, powered by educational meetings and individual feedback, improves MH performance by ICU nurses.

RELEVANCE TO CLINICAL PRACTICE

If it is decided to practice MH in the care of the intubated and mechanical ventilated patient, a standardized, uniform performed MH procedure is a prerequisite.

Year in review 2012: Critical Care--Respirology

Acute respiratory failure is a dominant feature of critical illness. In this review, we discuss 17 studies published last year in Critical Care. The discussion focuses on articles on several topics: respiratory monitoring, acute respiratory distress syndrome, noninvasive ventilation, airway management, secretion management and weaning.

[Risk of barotrauma when using non-reinhalation Waters valves: a comparative study on bench test]

OBJECTIVE

Manual ventilation is delivered in the operating room or the intensive care unit to intubated or non-intubated patients, using non-rebreathing systems such as the Waters valve. New generation Waters valves are progressively replacing the historic Waters valve. The aim of this study was to evaluate maximal pressure delivered by these 2 valves.

TYPE OF STUDY

Bench test.

MATERIAL AND METHOD

Thirty-two different conditions were tested, according to 2 oxygen flow rates (10 and 20L/min), without (static condition) or with manual insufflations (dynamic condition) and 4 valve expiratory opening pressures. The primary endpoint was maximal pressure measured at the exit of the valve, connected to a model lung and a bench test.

RESULTS

Measured pressures were different for most evaluated conditions. Increasing oxygen flow from 10 to 20L/min increased maximal pressure for both valves. Increasing valve expiratory opening pressure induced a significant increase in maximal pressure for the new generation valve (from 4 to 61cmH2O in static conditions and from 18 to 68cmH2O in dynamic conditions). For the historic valve, maximal pressure increased significantly but remained below 15cmH2O in both static and dynamic conditions.

CONCLUSION

Use of new generation Waters valves should be different from historic Waters valves. Indeed, barotrauma could be caused by badly adapted valve expiratory opening pressure settings.

Experimental study on the efficiency and safety of the manual hyperinflation maneuver as a secretion clearance technique

OBJECTIVE

To evaluate, in a lung model simulating a mechanically ventilated patient, the efficiency and safety of the manual hyperinflation (MH) maneuver as a means of removing pulmonary secretions.

METHODS

Eight respiratory therapists (RTs) were asked to use a self-inflating manual resuscitator on a lung model to perform MH as if to remove secretions, under two conditions: as routinely applied during their clinical practice; and after receiving verbal instructions based on expert recommendations. In both conditions, three clinical scenarios were simulated: normal lung function, restrictive lung disease, and obstructive lung disease.

RESULTS

Before instruction, it was common for an RT to compress the resuscitator bag two times, in rapid succession. Proximal pressure (Pprox) was higher before instruction than after. However, alveolar pressure (Palv) never exceeded 42.5 cmH₂O (median, 16.1; interquartile range [IQR], 11.7-24.5), despite Pprox values as high as 96.6 cmH₂O (median, 36.7; IQR, 22.9-49.4). The tidal volume (VT) generated was relatively low (median, 640 mL; IQR, 505-735), and peak inspiratory flow (PIF) often exceeded peak expiratory flow (PEF), the median values being 1.37 L/s (IQR, 0.99-1.90) and 1.01 L/s (IQR, 0.55-1.28), respectively. A PIF/PEF ratio < 0.9 (which theoretically favors mucus migration toward the central airways) was achieved in only 16.7% of the maneuvers.

CONCLUSIONS

Under the conditions tested, MH produced safe Palv levels despite high Pprox. However, the MH maneuver was often performed in a way that did not favor secretion removal (PIF exceeding PEF), even after instruction. The unfavorable PIF/ PEF ratio was attributable to overly rapid inflations and low VT.