Intrapulmonary percussive ventilation improves the outcome of patients with acute exacerbation of chronic obstructive pulmonary disease using a helmet

Clinical application of intrapulmonary percussive ventilation: A scoping review

Impaired respiratory function secondary to acute or chronic respiratory disease poses a significant clinical and healthcare burden. Intrapulmonary percussive ventilation (IPV) is used in various clinical settings to treat excessive airway secretions, pulmonary atelectasis, and impaired gas exchange. Despite IPV's wide use, there is a lack of clinical guidance on IPV application which may lead to inconsistency in clinical practice. This scoping review aimed to summarise the clinical application methods and dosage of IPV used by clinicians and researchers to provide guidance. A two-staged systematic search was conducted to retrieve studies that used IPV in inpatient and outpatient settings. MEDLINE, EMBASE, CINAHL, Scopus, and Google scholar were searched from January 1979 till 2022. Studies with patients aged ≥16 years and published in any language were included. Two reviewers independently screened the title and abstract, reviewed full text articles, and extracted data. Search yielded 514 studies. After removing duplicates and irrelevant studies, 25 studies with 905 participants met the inclusion criteria. This is the first scoping review to summarise IPV application methods and dosages from the available studies in intensive care unit (ICU), acute inpatient (non-ICU), and outpatient settings. Some variations in clinical applications and prescribed dosages of IPV were noted. Despite variations, common trends in clinical application and prescription of IPV dosages were observed and summarised to assist clinicians with IPV intervention. Although an evidence-based clinical guideline could not be provided, this review provides detailed information on IPV application and dosages in order to provide clinical guidance and lays a foundation towards developing a clinical practice guideline in the future.

Intrapulmonary percussive ventilation via Mini-Trach II in critical care: a case report

Background

Intrapulmonary percussive ventilation (IPV) facilitates the mobilization and clearance of bronchial secretions. Cricothyroidotomy using a Mini-Trach II device is a minimally invasive method used for secretion clearance. To our knowledge, there are no previous reports regarding IPV combined with Mini-Trach II.

Case presentation

An 82-year-old man underwent controlled mechanical ventilation and IPV via an endotracheal tube to treat atelectasis following emergency surgical repair of a traumatic diaphragm laceration. He underwent cricothyroidotomy using Mini-Trach II for ensuring airway management after extubation. On resumption, IPV through a mouthpiece or face mask was unsuccessful owing to air leakage from his mouth. However, IPV via the already inserted Mini-Trach II could deliver the percussion flow and led to a marked improvement in his condition.

Conclusion

This experience indicates that Mini-Trach II is beneficial as a minimally invasive interface for IPV that can deliver percussion flow efficiently.

Effect of intrapulmonary percussive ventilation on intensive care unit length of stay, the incidence of pneumonia and gas exchange in critically ill patients: A systematic review

Background

Pulmonary complications such as pneumonia, pulmonary atelectasis, and subsequent respiratory failure leading to ventilatory support are a common occurrence in critically ill patients. Intrapulmonary percussive ventilation (IPV) is used to improve gas exchange and promote airway clearance in these patients. The current evidence regarding the effectiveness of intrapulmonary percussive ventilation in critical care settings remains unclear. This systematic review aims to summarise the evidence of the effectiveness of intrapulmonary percussive ventilation on intensive care unit length of stay (ICU-LOS) and respiratory outcomes in critically ill patients.

Research question

In critically ill patients, is intrapulmonary percussive ventilation effective in improving respiratory outcomes and reducing intensive care unit length of stay.

Methods

A systematic search of intrapulmonary percussive ventilation in intensive care unit (ICU) was performed on five databases from 1979 to 2021. Studies were considered for inclusion if they evaluated the effectiveness of IPV in patients aged ≥16 years receiving invasive or non-invasive ventilation or breathing spontaneously in critical care or high dependency units. Study titles and abstracts were screened, followed by data extraction by a full-text review. Due to a small number of studies and observed heterogeneities in the study methodology and patient population, a meta-analysis could not be included in this review. Outcomes of interest were summarised narratively.

Results

Out of 306 identified abstracts, seven studies (630 patients) met the eligibility criteria. Results of the included studies provide weak evidence to support the effectiveness of intrapulmonary percussive ventilation in reducing ICU-LOS, improving gas exchange, and reducing respiratory rate.

Interpretation

Based on the findings of this review, the evidence to support the role of IPV in reducing ICU-LOS, improving gas exchange, and reducing respiratory rate is weak. The therapeutic value of IPV in airway clearance, preventing pneumonia, and treating pulmonary atelectasis requires further investigation.

Feasibility and safety of intrapulmonary percussive ventilation in spontaneously breathing, non-ventilated patients in critical care: A retrospective pilot study

Background

Intrapulmonary percussive ventilation is used in various clinical settings to promote secretion clearance, reverse or treat atelectasis and improve gas exchange. Despite a few studies reporting the use of intrapulmonary percussive ventilation in critical care, the available data remain insufficient, contributing to weaker evidence toward its effectiveness. Also, there is a paucity of studies evaluating the safety and feasibility of intrapulmonary percussive ventilation application in critical care. This retrospective pilot study has evaluated the safety and feasibility of intrapulmonary percussive ventilation intervention in non-intubated patients admitted to an intensive care unit.

Methods

The medical records of 35 subjects were reviewed, including 22 subjects who received intrapulmonary percussive ventilation intervention and 13 subjects matched for age, sex, and primary diagnosis who received chest physiotherapy. The records were audited for feasibility, safety, changes in oxygen saturation, chest X-ray changes, and intensive care unit length of stay.

Results

A total of 104 treatment sessions (IPV 65 and CPT 39) were delivered to subjects admitted with a range of respiratory conditions in critical care. Subjects completed 97% of IPV sessions. No major adverse events were reported with intrapulmonary percussive ventilation intervention. Intensive care unit length of stay in the intrapulmonary percussive ventilation group was 9.6 ± 6 days, and in the CPT group, it was 11 ± 9 days (p = 0.59). Peripheral oxygen saturation pre to post intervention was 92% ± 4 to 96% ± 4 in IPV group and 95% ± 4 to 95% ± 3 in the CPT group.

Conclusion

Application of intrapulmonary percussive ventilation intervention was feasible and safe in non-ventilated adult patients in critical care.

Acute Lobar Atelectasis

Lobar atelectasis (or collapse) is an exceedingly common, rather predictable, and potentially pathogenic companion to many forms of acute illness, postoperative care, and chronic debility. Readily diagnosed by using routine chest imaging and bedside ultrasound, the consequences from lobar collapse may be minor or serious, depending on extent, mechanism, patient vulnerability, abruptness of onset, effectiveness of hypoxic vasoconstriction, and compensatory reserves. Measures taken to reduce secretion burden, assure adequate secretion clearance, maintain upright positioning, reverse lung compression, and sustain lung expansion accord with a logical physiologic rationale. Both classification and logical approaches to prophylaxis and treatment of lobar atelectasis derive from a sound mechanistic knowledge of its causation.

The effect of intrapulmonary percussive ventilation in pediatric patients: A systematic review

BACKGROUND

Intrapulmonary percussive ventilation (IPV) is frequently used in clinical practice to enhance sputum evacuation and lung recruitment. However, the evidence in different respiratory pathologies, especially in children, is still lacking. This systematic review aims to enlist the effectiveness of IPV as an airway clearance technique in pediatric patients.

DATA SOURCES

A systematic literature search was performed in PubMed, Web of Science, and the Cochrane Library databases.

STUDY SELECTION

Studies were included if the subjects suffered from a respiratory disease requiring airway clearance and the mean age of the sample was <18 years. After screening, nine articles remained for further analysis.

RESULTS

Three of the nine articles examined patients with cystic fibrosis (CF). No significant differences in lung function or expectorated mucus were found compared to conventional chest physiotherapy. On the other hand, significant beneficial results were found for the treatment or prevention of atelectasis in non-CF patients using IPV. Similar results were seen when comparing therapies for neuromuscular/neurological patients. One study found that IPV reduced hospital stay and improved the clinical status of children with acute bronchiolitis compared to no physiotherapy. Severe adverse events did not occur in the included studies.

CONCLUSION

A limited number of studies investigated IPV in the pediatric population. Despite the heterogeneity across the studies and the small sample sizes, the results seem promising. IPV is suggested to be a safe and effective alternative for airway clearance. Future research is required to confirm these results and to further analyze the possible benefits in different respiratory pathologies.

Noninvasive ventilation in acute respiratory failure: which recipe for success?

Noninvasive positive-pressure ventilation (NPPV) to treat acute respiratory failure has expanded tremendously over the world in terms of the spectrum of diseases that can be successfully managed, the locations of its application and achievable goals.

The turning point for the successful expansion of NPPV is its ability to achieve the same physiological effects as invasive mechanical ventilation with the avoidance of the life-threatening risks correlated with the use of an artificial airway.

Cardiorespiratory arrest, extreme psychomotor agitation, severe haemodynamic instability, nonhypercapnic coma and multiple organ failure are absolute contraindications for NPPV. Moreover, pitfalls of NPPV reduce its rate of success; consistently, a clear plan of what to do in case of NPPV failure should be considered, especially for patients managed in unprotected setting. NPPV failure is likely to be reduced by the application of integrated therapeutic tools in selected patients handled by expert teams.

In conclusion, NPPV has to be considered as a rational art and not just as an application of science, which requires the ability of clinicians to both choose case-by-case the best “ingredients” for a “successful recipe” (i.e.patient selection, interface, ventilator, interface,etc.) and to avoid a delayed intubation if the ventilation attempt fails.

Safety and effectiveness of the high-frequency chest wall oscillation vs intrapulmonary percussive ventilation in patients with severe COPD

Purpose

Chest physiotherapy is an important tool in the treatment of COPD. Intrapulmonary percussive ventilation (IPV) and high-frequency chest wall oscillation (HFCWO) are techniques designed to create a global percussion of the lung which removes secretions and probably clears the peripheral bronchial tree. We tested the hypothesis that adding IPV or HFCWO to the best pharmacological therapy (PT) may provide additional clinical benefit over chest physiotherapy in patients with severe COPD.

Methods

Sixty patients were randomized into three groups (20 patients in each group): IPV group (treated with PT and IPV), PT group with (treated with PT and HFCWO), and control group (treated with PT alone). Primary outcome measures included results on the dyspnea scale (modified Medical Research Council) and Breathlessness, Cough, and Sputum scale (BCSS), as well as an evaluation of daily life activity (COPD Assessment Test [CAT]). Secondary outcome measures were pulmonary function testing, arterial blood gas analysis, and hematological examinations. Moreover, sputum cell counts were performed at the beginning and at the end of the study.

Results

Patients in both the IPV group and the HFCWO group showed a significant improvement in the tests of dyspnea and daily life activity evaluations (modified Medical Research Council scale, BCSS, and CAT) compared to the control group, as well as in pulmonary function tests (forced vital capacity, forced expiratory volume in 1 second, forced expiratory volume in 1 second/forced vital capacity%, total lung capacity, residual volume, diffusing lung capacity monoxide, maximal inspiratory pressure, maximal expiratory pressure) and arterial blood gas values. However, in the group comparison analysis for the same variables between IPV group and HFCWO group, we observed a significant improvement in the IPV group maximal inspiratory pressure, maximal expiratory pressure, BCSS, and CAT. Similar results were observed in changes of sputum cytology with reduction of inflammatory cells (neutrophils and macrophages).

Conclusion

The two techniques improved daily life activities and lung function in patients with severe COPD. IPV demonstrated a significantly greater effectiveness in improving some pulmonary function tests linked to the small bronchial airways obstruction and respiratory muscle strength and scores on health status assessment scales (BCSS and CAT) as well as a reduction of sputum inflammatory cells compared with HFCWO.

Effects of intrapulmonary percussive ventilation on airway mucus clearance: A bench model

AIM

To determine the ability of intrapulmonary percussive ventilation (IPV) to promote airway clearance in spontaneously breathing patients and those on mechanical ventilation.

METHODS

An artificial lung was used to simulate a spontaneously breathing patient (Group 1), and was then connected to a mechanical ventilator to simulate a patient on mechanical ventilation (Group 2). An 8.5 mm endotracheal tube (ETT) connected to the test lung, simulated the patient airway. Artificial mucus was instilled into the mid-portion of the ETT. A filter was attached at both ends of the ETT to collect the mucus displaced proximally (mouth-piece filter) and distally (lung filter). The IPV machine was attached to the proximal end of the ETT and was applied for 10-min each to Group 1 and 2. After each experiment, the weight of the various circuit components were determined and compared to their dry weights to calculate the weight of the displaced mucus.

RESULTS

In Group 1 (spontaneously breathing model), 26.8% ± 3.1% of the simulated mucus was displaced proximally, compared to 0% in Group 2 (the mechanically ventilated model) with a P-value of < 0.01. In fact, 17% ± 1.5% of the mucus in Group 2 remained in the mid-portion of the ETT where it was initially instilled and 80% ± 4.2% was displaced distally back towards the lung (P < 0.01). There was an overall statistically significant amount of mucus movement proximally towards the mouth-piece in the spontaneously breathing (SB) patient. There was also an overall statistically significant amount of mucus movement distally back towards the lung in the mechanically ventilated (MV) model. In the mechanically ventilated model, no mucus was observed to move towards the proximal/mouth piece section of the ETT.

CONCLUSION

This bench model suggests that IPV is associated with displacement of mucus towards the proximal mouthpiece in the SB patient, and distally in the MV model.

Early use of noninvasive techniques for clearing respiratory secretions during noninvasive positive-pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease and hypercapnic encephalopathy: A prospective cohort study

Noninvasive positive-pressure ventilation (NPPV) might be superior to conventional mechanical ventilation (CMV) in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPDs). Inefficient clearance of respiratory secretions provokes NPPV failure in patients with hypercapnic encephalopathy (HE). This study compared CMV and NPPV combined with a noninvasive strategy for clearing secretions in HE and AECOPD patients.The present study is a prospective cohort study of AECOPD and HE patients enrolled between October 2013 and August 2015 in a critical care unit of a major university teaching hospital in China.A total of 74 patients received NPPV and 90 patients received CMV. Inclusion criteria included the following: physician-diagnosed AECOPD, spontaneous airway clearance of excessive secretions, arterial blood gas analysis requiring intensive care, moderate-to-severe dyspnea, and a Kelly-Matthay scale score of 3 to 5. Exclusion criteria included the following: preexisting psychiatric/neurological disorders unrelated to HE, upper gastrointestinal bleeding, upper airway obstruction, acute coronary syndromes, preadmission tracheostomy or endotracheal intubation, and urgent endotracheal intubation for cardiovascular, psychomotor agitation, or severe hemodynamic conditions.Intensive care unit participants were managed by NPPV. Participants received standard treatment consisting of controlled oxygen therapy during NPPV-free periods; antibiotics, intravenous doxofylline, corticosteroids (e.g., salbutamol and ambroxol), and subcutaneous low-molecular-weight heparin; and therapy for comorbidities if necessary. Nasogastric tubes were inserted only in participants who developed gastric distension. No pharmacological sedation was administered.The primary and secondary outcome measures included comparative complication rates, durations of ventilation and hospitalization, number of invasive devices/patient, and in-hospital and 1-year mortality rates.Arterial blood gases and sensorium levels improved significantly within 2 hours in the NPPV group with lower hospital mortality, fewer complications and invasive devices/patient, and superior weaning off mechanical ventilation. Mechanical ventilation duration, hospital stay, or 1-year mortality was similar between groups.NPPV combined with a noninvasive strategy to clear secretions during the first 2 hours may offer advantages over CMV in treating AECOPD patients complicated by HE.

Effectiveness of airway clearance techniques in children hospitalized with acute bronchiolitis

OBJECTIVE

To evaluate the effectiveness of two airway clearance techniques (ACT's) in children <24 months hospitalized with mild to moderate bronchiolitis.

DESIGN

One hundred and three children were randomly allocated to receive one 20-min session daily, either assisted autogenic drainage (AAD), intrapulmonary percussive ventilation (IPV), or bouncing (B) (control group), ninety-three finished the study.

OUTCOME MEASURES

Mean time to recovery in days was our primary outcome measure. The impact of the treatment and the daily improvement was also assessed by a validated clinical and respiratory severity score (WANG score), heart rate (HR), and oxygen saturation (SaO₂ ).

RESULTS

Mean time to recovery was 4.5 ± 1.9 days for the control group, 3.6 ± 1.4 days, P < 0.05 for the AAD group and 3.5 ± 1.3 days, P = 0.03 for the IPV group. Wang scores improved significantly for both physiotherapy techniques compared to the control group.

CONCLUSION

Both ACT's reduced significantly the length of hospital stay compared to no physiotherapy. Pediatr Pulmonol. 2017;52:225-231. © 2016 Wiley Periodicals, Inc.

Intrapulmonary Percussive Ventilation as a Lung Recruitment Strategy in Brain-Dead Organ Donors

OBJECTIVE

To determine the strength of the evidence evaluating the effectiveness of intrapulmonary percussive ventilation (IPV) as a safe alternative or adjunctive therapy to traditional chest physiotherapy (CPT) among potential organ donors.

DATA SOURCES

Literature search conducted from February 2015 to November 2015 using PubMed, Cumulative Index of Nursing and Allied Health Literature, Scopus, and bibliographies of pertinent articles. Search Terms: Intrapulmonary percussive ventilation, chest physiotherapy, chest wall oscillation, organ donors, and ventilation.

STUDY SELECTION

Articles in English from 1994 to present directly compared IPV to CPT or conventional (no) therapy.

DATA EXTRACTION

Association of Critical-Care Nurses Levels of Evidence was used to determine the strength of evidence. Level B and level C articles were reviewed.

DATA SYNTHESIS

No studies were found using IPV in the donor population. Results from studies using IPV in other populations indicated IPV had no adverse effects, improved sputum clearance and oxygenation, and reduced atelectasis and pneumonia in patients with artificial airways.

CONCLUSION

Intrapulmonary percussive ventilation may be a safe and effective alternative or adjunctive to CPT therapy and improve the number of lungs available for transplantation. Clinical research is essential to determine the effectiveness of this therapy for lung recruitment in the donor population.

Timing of noninvasive ventilation failure: causes, risk factors, and potential remedies

Background

Identifying the predictors of noninvasive ventilation (NIV) failure has attracted significant interest because of the strong link between failure and poor outcomes. However, very little attention has been paid to the timing of the failure. This narrative review focuses on the causes of NIV failure and risk factors and potential remedies for NIV failure, based on the timing factor.

Results

The possible causes of immediate failure (within minutes to <1 h) are a weak cough reflex, excessive secretions, hypercapnic encephalopathy, intolerance, agitation, and patient-ventilator asynchrony. The major potential interventions include chest physiotherapeutic techniques, early fiberoptic bronchoscopy, changing ventilator settings, and judicious sedation. The risk factors for early failure (within 1 to 48 h) may differ for hypercapnic and hypoxemic respiratory failure. However, most cases of early failure are due to poor arterial blood gas (ABGs) and an inability to promptly correct them, increased severity of illness, and the persistence of a high respiratory rate. Despite a satisfactory initial response, late failure (48 h after NIV) can occur and may be related to sleep disturbance.

Conclusions

Every clinician dealing with NIV should be aware of these risk factors and the predicted parameters of NIV failure that may change during the application of NIV. Close monitoring is required to detect early and late signs of deterioration, thereby preventing unavoidable delays in intubation.

Airway clearance techniques for chronic obstructive pulmonary disease

BACKGROUND

Cough and sputum production are common in chronic obstructive pulmonary disease (COPD) and are associated with adverse clinical outcomes. Airway clearance techniques (ACTs) aim to remove sputum from the lungs, however evidence of their efficacy during acute exacerbations of COPD (AECOPD) or stable disease is unclear.

OBJECTIVES

To assess the safety and efficacy of ACTs for individuals with AECOPD and stable COPD.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials from inception to October 2011, and PEDro in October 2009.

SELECTION CRITERIA

We included randomised parallel trials and randomised cross-over trials which compared an ACT to no treatment, cough or sham ACT in participants with investigator-defined COPD, emphysema or chronic bronchitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently conducted data extraction and assessed the risk of bias. We analysed data from studies of AECOPD separately from stable COPD, and classified the effects of ACTs as 'immediate' (less than 24 hours), 'short-term' (24 hours to eight weeks) or 'long-term' (greater than eight weeks). One subgroup analysis compared the effects of ACTs that use positive expiratory pressure (PEP) to those that do not.

MAIN RESULTS

Twenty-eight studies on 907 participants were included in the review. Study sample size was generally small (range 5 to 96 people) and overall quality was generally poor due to inadequate blinding and allocation procedures. Meta-analyses were limited by heterogeneity of outcome measurement and inadequate reporting of data.In people experiencing AECOPD, ACT use was associated with small but significant short-term reductions in the need for increased ventilatory assistance (odds ratio (OR) 0.21, 95% confidence interval (CI) 0.05 to 0.85; data from four studies on 171 people), the duration of ventilatory assistance (mean difference (MD) -2.05 days, 95% CI -2.60 to -1.51; mean duration for control groups seven days; data from two studies on 54 people) and hospital length of stay (MD -0.75 days, 95% CI -1.38 to -0.11; mean duration for control groups nine days; one study on 35 people). Data from a limited number of studies revealed no significant long-term benefits of ACTs on the number of exacerbations or hospitalisations, nor any short-term beneficial effect on health-related quality of life (HRQoL) as measured by the St. George's Respiratory Questionnaire (SGRQ) total score (MD -2.30, 95% CI -11.80 to 7.20; one study on 59 people).In people with stable COPD, data from single studies revealed no significant short-term benefit of ACTs on the number of people with exacerbations (OR 3.21, 95% CI 0.12 to 85.20; one study on 30 people), significant short-term improvements in HRQoL as measured by the SGRQ total score (MD -6.10, 95% CI -8.93 to -3.27; one study on 15 people) and a reduced long-term need for respiratory-related hospitalisation (OR 0.27, 95% CI 0.08 to 0.95; one study on 35 participants).The magnitude of effect of PEP-based ACTs on the need for increased ventilatory assistance and hospital length of stay was greater than for non-PEP ACTs, however we found no statistically significant subgroup differences. There was one report of vomiting during treatment with postural drainage and head-down tilt.

AUTHORS' CONCLUSIONS

Evidence from this review indicates that airway clearance techniques are safe for individuals with COPD and confer small beneficial effects on some clinical outcomes. Consideration may be given to the use of airway clearance techniques for patients with COPD in both acute and stable disease, however current studies suggest that the benefits achieved may be small.

Comparison of noninvasive ventilation by sequential use of mask and helmet versus mask in acute exacerbation of chronic obstructive pulmonary disease: a preliminary study

BACKGROUND

Noninvasive positive pressure ventilation (NPPV) using a face mask is the ventilatory mode of choice in selected patients experiencing acute exacerbation of chronic obstructive pulmonary disease (COPD). A high incidence of intolerance limits the use of this approach.

OBJECTIVE

To evaluate the sequential use of mask and helmet during NPPV in patients with severe exacerbation of COPD in order to reduce the intolerance to these devices.

METHODS

Fifty-three patients ventilated for the first 2 h with NPPV by mask were studied. If gas exchange and clinical status improved, they were randomized to continue on NPPV by mask or helmet. Physiological parameters were measured at admission, after the first 2 h on NPPV by mask, 4 h after randomization and at discharge. Need for intubation, ventilatory assistance, length of stay (LOS) and complications were recorded.

RESULTS

After the first 2 h of NPPV, gas exchange and clinical parameters improved in 40 patients. Four hours after randomization, PaCO(2) was lower in the mask group than in the helmet group. Nine patients in the mask group and 2 in the helmet group failed NPPV, 8 and 1, respectively, owing to intolerance. Time of noninvasive ventilation and LOS were lower in the mask than in the helmet group.

CONCLUSIONS

In patients with acute exacerbation of COPD and undergoing NPPV, the sequential use of a mask and helmet diminished the incidence of failure. Under the present experimental conditions, the use of a helmet increased LOS and the duration of artificial ventilation.

Hypercapnic encephalopathy syndrome: a new frontier for non-invasive ventilation?

According to the classical international guidelines, non-invasive ventilation is contraindicated in hypercapnic encephalopathy syndrome (HES) due to the poor compliance to ventilatory treatment of confused/agitated patients and the risk of aspirative pneumonia related to lack of airways protection. As a matter of fact, conventional mechanical ventilation has been recommended as "golden standard" in these patients. However, up to now there are not controlled data that have demonstrated in HES the advantage of conventional mechanical ventilation vs non-invasive ventilation. In fact, patients with altered mental status have been systematically excluded from the randomised and controlled trials performed with non-invasive ventilation in hypercapnic acute respiratory failure. Recent studies have clearly demonstrated that an initial cautious NPPV trial in selected HES patients may be attempt as long as there are no other contraindications and the technique is provided by experienced caregivers in a closely monitored setting where ETI is always readily available. The purpose of this review is to report the physiologic rationale, the clinical feasibility and the still open questions about the careful use of non-invasive ventilation in HES as first-line ventilatory strategy in place of conventional mechanical ventilation via endotracheal intubation.

Gas distribution in a two-compartment model ventilated in high-frequency percussive and pressure-controlled modes

PURPOSE

To demonstrate in a two-compartment heterogeneous mechanical model of the lung how different loads applied to one compartment, while the other is kept constant, would modify gas distribution between the two pathways under high-frequency percussive ventilation (HFPV). Additionally, these results were compared with those generated in the same model by pressure-controlled ventilation (PCV).

METHODS

Analysis was based on a Siemens lung simulator, representing a fixed branch of the system with an elastance equal to 45 cmH(2)O/L and a resistance of 20 cmH(2)O/L/s, and a single-compartment lung simulator, representing a variable pathway of the model, presenting three elastic loads varying between 35 and 85 cmH(2)O/L and three resistive loads varying between 5 and 50 cmH(2)O/L/s. Each simulator represented one compartment of the model connected to a central airway that was ventilated with either a volumetric diffusive respirator (VDR-4; Percussionaire Corporation, Sandpoint, ID, USA) or a Siemens Servo 900c ventilator. Flow and pressures were measured in each branch of the model under nine conditions representing the combinations of three elastic and three resistive loads (variable branch) while the loads in the other pathway were kept constant.

RESULTS

HFPV was able to avoid hyperinflation and reduce tidal volume in a bicompartmental heterogeneous lung model. Under HFPV, gas distribution between the two compartments was not constrained by their time constants. PCV yielded gas distribution as determined by the time constant of each compartment.

CONCLUSIONS

HFPV accommodated volume distribution without overinflating compartments with low time constants, thus possibly presenting a potential protective behavior in mechanically heterogeneous lungs.

Early fiberoptic bronchoscopy during non-invasive ventilation in patients with decompensated chronic obstructive pulmonary disease due to community-acquired-pneumonia

INTRODUCTION

Inefficient clearance of copious respiratory secretion is a cause of non-invasive positive pressure ventilation (NPPV) failure, especially in chronic respiratory patients with community-acquired-pneumonia (CAP) and impaired consciousness. We postulated that in such a clinical scenario, when intubation and conventional mechanical ventilation (CMV) are strongly recommended, the suction of secretions with fiberoptic bronchoscopy (FBO) may increase the chance of NPPV success. The objective of this pilot study was, firstly, to verify the safety and effectiveness of early FBO during NPPV and, secondly, to compare the hospital outcomes of this strategy versus a CMV-based strategy in patients with decompensated chronic obstructive pulmonary disease (COPD) due to CAP who are not appropriate candidates for NPPV because of inefficient mucous clearance and hypercapnic encephalopathy (HE).

METHODS

This is a 12-month prospective matched case-control study performed in one respiratory semi-intensive care unit (RSICU) with expertise in NPPV and in one intensive care unit (ICU). Fifteen acutely decompensated COPD patients with copious secretion retention and HE due to CAP undergoing NPPV in RSICU, and 15 controls (matched for arterial blood gases, acute physiology and chronic health evaluation score III, Kelly-Matthay scale, pneumonia extension and severity) receiving CMV in the ICU were studied.

RESULTS

Two hours of NPPV significantly improved arterial blood gases, Kelly and cough efficiency scores without FBO-related complications. NPPV avoided intubation in 12/15 patients (80%). Improvement in arterial blood gases was similar in the two groups, except for a greater PaO2/fraction of inspired oxygen ratio with CMV. The rates of overall and septic complications, and of tracheostomy were lower in the NPPV group (20%, 20%, and 0%) versus the CMV group (80%, 60%, and 40%; P < 0.05). Hospital mortality, duration of hospitalisation and duration of ventilation were similar in the two groups.

CONCLUSIONS

In patients with decompensated COPD due to CAP who are candidates for CMV because of HE and inability to clear copious secretions, NPPV with early therapeutic FBO performed by an experienced team is a feasible, safe and effective alternative strategy.

High-frequency percussive ventilation improves perioperatively clinical evolution in pulmonary resection

OBJECTIVE

During thoracotomy, positive end-expiratory pressure is applied to the dependent lung and continuous positive airway pressure (CPAP) inflates the nondependent lung to avoid hypoxemia. These methods do not allow the removal of produced secretions. We hypothesized that high-frequency percussive ventilation(HFPV) can improve both conditions and reduce hospital length of stay in these patients.

DESIGN

Randomized prospective study.

SETTING

University Hospital.

PATIENTS

Fifty-three consecutive patients undergoing elective pulmonary partial resection were enrolled. Nine were excluded because of surgical reasons.

INTERVENTIONS

The nondependent lung was ventilated with HFPV in 22 patients and other 22 received CPAP. In both groups,the dependent lung was ventilated with continuous mechanical ventilation.

MEASUREMENT AND MAIN RESULTS

Cardiocirculatory variables and blood gas analysis were measured during surgery. Postoperatively,all patients underwent chest physiotherapy, and SpO2,body temperature, the amount of sputum produced, and chest radiography were recorded. Before nondependent lung re-expansion,HFPV patients presented higher PaO2 than CPAP group (p = 0.020). The amount of secretions was higher in chronic obstructive pulmonary disease patients treated with HFPV than in those who received CPAP (199 and 64 mL, respectively, p = 0.028). HFPV increased by 5.28 times the chance of sputum production by chronic obstructive pulmonary disease patients (chi(2) = 46.66, p < 0.0001; odds ratio = 5.28). A patient treated with HFPV had a 3.14-fold larger chance of being discharged earlier than a CPAP-treated subject (likelihood ratio = 11.5, p = 0.0007).

CONCLUSIONS

Under the present settings, HFPV improved oxygenation in one-lung ventilation during pulmonary resection. Postoperatively, it decreased the length of stay and increased the removal of secretions in comparison with CPAP.

Severe Legionella pneumonia successfully treated by independent lung ventilation with intrapulmonary percussive ventilation

A case of severe Legionella pneumonia was successfully treated by independent lung ventilation (ILV) with intrapulmonary percussive ventilation (IPV). A 57-year-old man with lobar pneumonia was intubated and mechanically ventilated because of his deteriorating respiratory status. The diagnosis of Legionella pneumonia was made on the fourth day after admission and appropriate antibiotic therapy was commenced. On the fifth hospital day, ILV was commenced because the right unaffected lung was over-distended, his haemodynamic state was unstable and his left lung was producing copious amounts of purulent sputum. His right lung was ventilated and his left lung was treated with IPV owing to the existence of massive atelectasis. After treatment with antibiotics and ILV combined with IPV, his respiratory and haemodynamic status gradually improved. On the tenth day after admission, ILV was changed to conventional bilateral ventilation. The patient was extubated on the sixteenth hospital day and discharged from the intensive care unit 30 days after admission. The combination of ILV and IPV was therapeutically effective during the acute phase of unilateral severe Legionella pneumonia.

Effect of intrapulmonary percussive ventilation on expiratory flow limitation in chronic obstructive pulmonary disease patients

PURPOSE

The aims of this prospective study were (1) to select, after weaning and extubation, chronic obstructive pulmonary disease (COPD) patients with expiratory flow limitation (EFL) measured by the negative expiratory pressure method and (2) to assess, in these patients, the short-term (30 minutes) physiologic effect of a session of intrapulmonary percussive ventilation (IPV).

MATERIALS AND METHODS

All COPD patients who were intubated and needed weaning from mechanical ventilation were screened after extubation. The patients were placed in half-sitting position and breathed spontaneously. The EFL and the airway occlusion pressure after 0.1 second (P0.1) were measured at the first hour after extubation. In COPD patients with EFL, an IPV session of 30 minutes was promptly performed by a physiotherapist accustomed to the technique. Expiratory flow limitation, gas exchange, and P0.1 were recorded at the end of the IPV session.

RESULTS

Among 35 patients studied after extubation, 25 patients presented an EFL and were included in the study. Intrapulmonary percussive ventilation led to a significant improvement in EFL, respectively, before and 30 minutes after IPV (65.4 +/- 18.2 vs 35.6 +/- 22.8; P < .05). Three patients were not expiratory flow limited after IPV. Intrapulmonary percussive ventilation led to a significant decrease in P0.1 (3.9 +/- 1.6 vs 2.8 +/- 1.1; P < .05). Thirty minutes of IPV led to a significant increase in Pao(2) and pH and a decrease in Paco(2) and respiratory rate (P < .05).

CONCLUSION

In COPD patients, a session of IPV allowed a significant reduction of EFL and of P01 and a significant improvement of gas exchange.