A survey of manual hyperinflation in Australian hospitals

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.

Benefits of secretion clearance with high frequency percussive ventilation in tracheostomized critically ill patients: a pilot study

Clearance of secretions remains a challenge in ventilated patients. Despite high-frequency percussive ventilation (HFPV) showing benefits in patients with cystic fibrosis and neuromuscular disorders, very little is known about its effects on other patient categories. Therefore, we designed a physiological pilot study investigating the effects on lung aeration and gas exchange of short HFPV cycles in tracheostomized patients undergoing mechanical ventilation. Electrical impedance tomography (EIT) was recorded at baseline (T0) by a belt wrapped around the patient's chest, followed by the HFPV cycle lasting 10 min. EIT data was collected again after the HFPV cycle (T1) as well as after 1 h (T2) and 3 h (T3) from T0. Variation from baseline of end-expiratory lung impedance (∆EELI), tidal variation (TIV) and global inhomogeneity index (GI) were computed. Arterial blood was also taken for gas analysis. HFPV cycle significantly improved the ∆EELI at T1, T2 and T3 when compared to baseline (p < 0.05 for all comparisons). The ratio between arterial partial pressure and inspired fraction of oxygen (PaO₂/FiO₂) also increased after the treatment (p < 0.001 for all comparison) whereas TIV (p = 0.132) and GI (p = 0.114) remained unchanged. Short cycles of HFPV superimposed to mechanical ventilation promoted alveolar recruitment, as suggested by improved ∆EELI, and improved oxygenation in tracheostomized patients with high load of secretion.Trial Registration Prospectively registered on www.clinicaltrials.gov (NCT05200507; dated 6th January 2022).

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

Background

Besides airway suctioning, patients undergoing invasive mechanical ventilation (iMV) benefit of different combinations of chest physiotherapy techniques, to improve mucus removal. To date, little is known about the clearance effects of oscillating devices on patients with acute respiratory failure undergoing iMV. This study aimed to assess (1) the effects of high-frequency chest wall oscillation (HFCWO) on lung aeration and ventilation distribution, as assessed by electrical impedance tomography (EIT), and (2) the effect of the association of HFCWO with recruitment manoeuvres (RM).

Methods

Sixty critically ill patients, 30 classified as normosecretive and 30 as hypersecretive, who received ≥ 48 h of iMV, underwent HFCWO; patients from both subgroups were randomized to receive RM or not, according to two separated randomization sequences. We therefore obtained four arms of 15 patients each. After baseline record (T0), HFCWO was applied for 10 min. At the end of the treatment (T1) or after 1 (T2) and 3 h (T3), EIT data were recorded. At the beginning of each step, closed tracheobronchial suctioning was performed. In the RM subgroup, tracheobronchial suctioning was followed by application of 30 cmH₂O to the patient’s airway for 30 s. At each step, we assessed the change in end-expiratory lung impedance (ΔEELI) and in tidal impedance variation (ΔTIV), and the center of gravity (COG) through EIT. We also analysed arterial blood gases (ABGs).

Results

ΔTIV and COG did not differ between normosecretive and hypersecretive patients. Compared to T0, ΔEELI significantly increased in hypersecretive patients at T2 and T3, irrespective of the RM; on the contrary, no differences were observed in normosecretive patients. No differences of ABGs were recorded.

Conclusions

In hypersecretive patients, HFCWO significantly improved aeration of the dorsal lung region, without affecting ABGs. The application of RM did not provide any further improvements.

Trial registration

Prospectively registered at the Australian New Zealand Clinical Trial Registry (www.anzctr.org.au; number of registration: ACTRN12615001257550; date of registration: 17th November 2015).

Ventilator hyperinflation determined by peak airway pressure delivered: A randomized crossover trial

AIM

The aim of this study was to see if a more sophisticated ventilator hyperinflation protocol might result in more sputum clearance compared to manual hyperinflation.

BACKGROUND

Hyperinflation has been used to mobilize lung secretions in mechanically ventilated patients in the intensive care unit setting for almost 50 years. In the past decade, rather than using a bag external to the ventilator circuit to deliver hyperinflation (known as "bagging" or "manual hyperinflation"), a new technique has evolved using existing ventilator circuitry (known as "ventilator hyperinflation"). One conservative ventilator hyperinflation protocol has demonstrated equivalence with manual hyperinflation in sputum clearance.

DESIGN

A randomized crossover study.

METHOD

Patients received manual hyperinflation and ventilator hyperinflation in two randomly ordered treatments on the same day by the same physiotherapist, using a ventilator hyperinflation protocol involving titration of hyperinflation according to airway pressure.

RESULTS

Between 2013 and 2018, 48 patients were enrolled in the study. Physiotherapy treatment using ventilator hyperinflation yielded significantly more wet weight sputum (median 2.84 g, IQR 1.81, 4.22) than treatment using manual hyperinflation (median 1.5 g, IQR 0.73, 2.31, P < .001), without significant differences in secondary measures.

CONCLUSIONS

A more sophisticated approach to the titration of the volume delivered using ventilator hyperinflation relative to the airway pressure resulted in greater wet weight sputum cleared during physiotherapy treatment.

RELEVANCE TO CLINICAL PRACTICE

The results presented in this paper demonstrate that the application of ventilator hyperinflation using peak airway pressure rather than tidal volume may be superior in facilitating sputum clearance and improved oxygenation without patient harm.

Comparison of bronchial hygiene techniques in mechanically ventilated patients: a randomized clinical trial

OBJECTIVE

To compare the effects of vibrocompression and hyperinflation with mechanical ventilator techniques alone and in combination (hyperinflation with mechanical ventilator + vibrocompression) on the amount of aspirated secretion and the change in hemodynamic and pulmonary parameters.

METHODS

A randomized clinical trial with critically ill patients on mechanical ventilation conducted in the intensive care unit of a university hospital. The patients were randomly allocated to receive one of the bronchial hygiene techniques for 10 minutes (vibrocompression or hyperinflation with mechanical ventilator or hyperinflation with mechanical ventilator + vibrocompression). Afterwards, the patients were again randomly allocated to receive either the previous randomly allocated technique or only tracheal aspiration. The weight of aspirated secretions (in grams), ventilatory mechanics and cardiopulmonary data before and after the application of the techniques were analyzed. The tracheal reintubation frequency and time and mortality on mechanical ventilation were also evaluated.

RESULTS

A total of 93 patients (29 vibrocompression, 32 hyperinflation with mechanical ventilator and 32 hyperinflation with mechanical ventilator + vibrocompression) on mechanical ventilation for more than 24 hours were included. The hyperinflation with mechanical ventilator + vibrocompression group was the only one that presented a significant increase in aspirated secretions compared to tracheal aspiration alone [0.7g (0.1 - 2.5g) versus 0.2g (0.0 - 0.6g), p value = 0.006].

CONCLUSION

Compared to tracheal aspiration alone, the combination of hyperinflation with mechanical ventilator + vibrocompression techniques was most efficient for increasing the amount of aspirated secretions.

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.

Manual hyperinflation and the role of physical therapy in intensive care and emergency units

Abstract Introduction: Although manual hyperinflation (MHI) is a physical therapy technique commonly used in intensive care and emergency units, there is little consensus about its use. Objective: To investigate the knowledge of physical therapists working in intensive care and emergency units about manual hyperinflation. Methods: Data were collected through self-administered questionnaires on manual hyperinflation. Data collection took place between September 2014 and January 2015, in Itabuna and Ilhéus, Bahia, Brazil. Results: The study sample was composed of 32 physical therapists who had between 4 months and 10 years working experience. All respondents affirmed that they used the technique in their professional practice. However, only 34.4% reported it to be a routine practice. 90.6% stated that the most common patient position during manual hyperinflation is “supine”. Participants were almost unanimous (93.8%) in citing secretion removal and cough stimulation as perceived benefits of MHI. High peak airway pressure was identified as being a precaution to treatment with MHI by 84.4% of participants, whilst 100% of the sample agreed that an undrained pneumothorax was a contraindication to MHI. Conclusion: The most common answers to the questionnaire were: supine position during MHI; secretion removal and cough stimulation as perceived benefits; high peak airway pressure as a precaution; and an undrained pneumothorax as a contraindication.

Indications for manual lung hyperinflation (MHI) in the mechanically ventilated patient with chronic obstructivepulmonary disease

Manual lung hyperinflation (MHI) can enhance secretion clearance, improve total lung/thorax compliance and assistin the resolution of acute atelectasis. To enhance secretion clearance in the intubated patient, the evidence highlights the need to maximize expiratory flow. Chronic pulmonary diseases such as chronic obstructive pulmonary disease(COPD) have often been cited as potential precautions and/or contra-indications to the use of manual lung hyperinflation (MHI). There is an absence of evidence on the effects of MHI in the patient with COPD. Research on the effects of mechanical ventilation in the patient with COPD providesa useful clinical examination of the effect of positive pressure on cardiac and pulmonary function. The potential effects of MHI in the COPD patient group were extrapolated on the basis of the MHI and mechanical ventilation literature. There is the potential for MHI to have both detrimental and beneficial effects on cardiac and pulmonary functionin patients with COPD. The potential detrimental effects of MHI may include either, increased intrinsic peep throughinadequate time for expiration by the breath delivery rate, tidal volume delivered or through the removal of appliedextemal PEEP thereby causing more dynamic airway compression compromising downward expiratory flow, which may also retard bronchial mucus transport. MHI may also increase right ventricular after load through raised intrathoracic pressures with lung hyperinflation, and may therefore impair right ventricular function in patients with evidence of cor pulmonale. There is the potential for beneficial effectsfrom MHI in the intubated COPD patient group (i.e., secretion clearance), but further research is required, especially on the effect of MHI on inspiratory and expiratory flowrate profiles in this patient group. The more controlled delivery of lung hyperinflation through the use of the mechanical ventilator may be a more optimal means of providinglunghyperinflation and shouldbe furtherinvestigated.

National Profile of Physical Therapists in Critical Care Units of Sri Lanka: Lower Middle-Income Country

BACKGROUND

The availability and role of physical therapists in critical care is variable in resource-poor settings, including lower middle-income countries.

OBJECTIVE

The aim of this study was to determine: (1) the availability of critical care physical therapist services, (2) the equipment and techniques used and needed, and (3) the training and continuous professional development of physical therapists.

METHODS

All physical therapists working in critical care units (CCUs) of state hospitals in Sri Lanka were contacted. The study tool used was an interviewer-administered telephone questionnaire.

RESULTS

The response rate was 100% (N=213). Sixty-one percent of the physical therapists were men. Ninety-four percent of the respondents were at least diploma holders in physical therapy, and 6% had non-physical therapy degrees. Most (n=145, 68%) had engaged in some continuous professional development in the past year. The majority (n=119, 56%) attended to patients after referral from medical staff. Seventy-seven percent, 98%, and 96% worked at nights, on weekends, and on public holidays, respectively. Physical therapists commonly perform manual hyperinflation, breathing exercises, manual airway clearance techniques, limb exercises, mobilization, positioning, and postural drainage in the CCUs. Lack of specialist training, lack of adequate physical therapy staff numbers, a heavy workload, and perceived lack of infection control in CCUs were the main difficulties they identified.

LIMITATIONS

Details on the proportions of time spent by the physical therapists in the CCUs, wards, or medical departments were not collected.

CONCLUSIONS

The availability of physical therapist services in CCUs in Sri Lanka, a lower middle-income country, was comparable to that in high-income countries, as per available literature, in terms of service availability and staffing, although the density of physical therapists remained very low, critical care training was limited, and resource limitations to physical therapy practices were evident.

Performance of manual hyperinflation: consistency and modification of the technique by intensive care unit nurses during physiotherapy

AIMS AND OBJECTIVES

To assess the consistency and safety of manual hyperinflation delivery by nurses of variable clinical experience using a resuscitator bag during physiotherapy treatment.

BACKGROUND

Manual hyperinflation involves the delivery of larger than normal gas volumes to intubated patients and is routinely used by nurses in collaboration with physiotherapists for the management of retained sputum. The aim is to deliver slow deep breaths with an inspiratory hold without unsafe airway pressures, lung volumes or haemodynamic changes. In addition, nursing staff should be able to 'feel' differences in resistance and adjust their technique accordingly.

DESIGN

Prospective observational study utilising the simulation of a mechanically ventilated patient.

METHODS

Thirty-three nurses delivered manual hyperinflation to a SimMan3G mannequin who had three distinct lung scenarios applied (normal; asthma; Acute Respiratory Distress Syndrome) in randomised order during simulated physiotherapy treatment. Respiratory rate, tidal volume (Vt ), mean inspiratory flow rate (Vt /Ti), and peak airway pressure data were generated.

RESULTS

Over all scenarios, mean respiratory rate = 12·3 breaths/minute, mean Vt  = 638·6 mls, mean inflation time = 1·3 seconds and peak airway pressure exceeded 40 cm H2 O in 41% of breaths, although only in 10% of breaths during the 'normal' lung scenario.

CONCLUSIONS

Experienced nurses were able to manually hyperinflate 'normal' patients in a simulated setting safely. Despite their knowledge of barotrauma, unsafe airway pressures were delivered in some scenarios.

RELEVANCE TO CLINICAL PRACTICE

Training with regard to safe airway pressures, breath hold and adequate volumes is recommended for all nurses undertaking the procedure. Nurses and physiotherapists must closely monitor the patient's condition during manual hyperinflation thereby recognising changes with regard to lung compliance and airway resistance, with nurses responding by altering their technique. The addition of a pressure manometer in the circuit may improve patient safety when performing manual hyperinflation.

Chest compression with a higher level of pressure support ventilation: effects on secretion removal, hemodynamics, and respiratory mechanics in patients on mechanical ventilation

OBJECTIVE

To determine the efficacy of chest compression accompanied by a 10-cmH2O increase in baseline inspiratory pressure on pressure support ventilation, in comparison with that of aspiration alone, in removing secretions, normalizing hemodynamics, and improving respiratory mechanics in patients on mechanical ventilation.

METHODS

This was a randomized crossover clinical trial involving patients on mechanical ventilation for more than 48 h in the ICU of the Porto Alegre Hospital de Clínicas, in the city of Porto Alegre, Brazil. Patients were randomized to receive aspiration alone (control group) or compression accompanied by a 10-cmH2O increase in baseline inspiratory pressure on pressure support ventilation (intervention group). We measured hemodynamic parameters, respiratory mechanics parameters, and the amount of secretions collected.

RESULTS

We included 34 patients. The mean age was 64.2 ± 14.6 years. In comparison with the control group, the intervention group showed a higher median amount of secretions collected (1.9 g vs. 2.3 g; p = 0.004), a greater increase in mean expiratory tidal volume (16 ± 69 mL vs. 56 ± 69 mL; p = 0.018), and a greater increase in mean dynamic compliance (0.1 ± 4.9 cmH2O vs. 2.8 ± 4.5 cmH2O; p = 0.005).

CONCLUSIONS

In this sample, chest compression accompanied by an increase in pressure support significantly increased the amount of secretions removed, the expiratory tidal volume, and dynamic compliance. (ClinicalTrials.gov Identifier:NCT01155648 [http://www.clinicaltrials.gov/]).

Manual hyperinflation combined with expiratory rib cage compression for reduction of length of ICU stay in critically ill patients on mechanical ventilation

OBJECTIVE

Although manual hyperinflation (MH) is widely used for pulmonary secretion clearance, there is no evidence to support its routine use in clinical practice. Our objective was to evaluate the effect that MH combined with expiratory rib cage compression (ERCC) has on the length of ICU stay and duration of mechanical ventilation (MV).

METHODS

This was a prospective randomized controlled clinical trial involving ICU patients on MV at a tertiary care teaching hospital between January of 2004 and January of 2005. Among the 49 patients who met the study criteria, 24 and 25 were randomly assigned to the respiratory physiotherapy (RP) and control groups, respectively. Of those same patients, 6 and 8, respectively, were later withdrawn from the study. During the 5-day observation period, the RP patients received MH combined with ERCC, whereas the control patients received standard nursing care.

RESULTS

The two groups were similar in terms of the baseline characteristics. The intervention had a positive effect on the duration of MV, as well as on the ICU discharge rate and Murray score. There were significant differences between the control and RP groups regarding the weaning success rate on days 2 (0.0% vs. 37.5%), 3 (0.0% vs. 37.5%), 4 (5.3% vs. 37.5%), and 5 (15.9% vs. 37.5%), as well as regarding the ICU discharge rate on days 3 (0% vs. 25%), 4 (0% vs. 31%), and 5 (0% vs. 31%). In the RP group, there was a significant improvement in the Murray score on day 5.

CONCLUSIONS

Our results show that the use of MH combined with ERCC for 5 days accelerated the weaning process and ICU discharge.

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

Introduction

Manual hyperinflation (MH), a frequently applied maneuver in critically ill intubated and mechanically ventilated patients, is suggested to mimic a cough so that airway secretions are mobilized toward the larger airways, where they can easily be removed. As such, MH could prevent plugging of the airways.

Methods

We performed a search in the databases of Medline, Embase, and the Cochrane Library from January 1990 to April 2012. We systematically reviewed the literature on evidence for postulated benefits and risks of MH in critically ill intubated and mechanically ventilated patients.

Results

The search identified 50 articles, of which 19 were considered relevant. We included 13 interventional studies and six observational studies. The number of studies evaluating physiological effects of MH is limited. Trials differed too much to permit meta-analysis. It is uncertain whether MH was applied similarly in the retrieved studies. Finally, most studies are underpowered to show clinical benefit of MH. Use of MH is associated with short-term improvements in lung compliance, oxygenation, and secretion clearance, without changes in outcomes. MH has been reported to be associated with short-term and probably clinically insignificant side effects, including decreases in cardiac output, alterations of heart rates, and increased central venous pressures.

Conclusions

Studies have failed to show that MH benefits critically ill intubated and mechanically ventilated patients. MH is infrequently associated with short-term side effects.

Ventilator versus manual hyperinflation in clearing sputum in ventilated intensive care unit patients

The aim of hyperinflation in the ventilated intensive care unit patient is to increase oxygenation, reverse lung collapse and clear sputum. The efficacy and consistency of manual hyperventilation is well supported in the literature, but there is limited published evidence supporting hyperventilation utilising a ventilator. Despite this, a recent survey established that almost 40% of Australian tertiary intensive care units utilise ventilator hyperinflation. The aim of this non-inferiority cross-over study was to determine whether ventilator hyperinflation was as effective as manual hyperinflation in clearing sputum from patients receiving mechanical ventilation using a prescriptive ventilator hyperinflation protocol. Forty-six patients received two randomly ordered physiotherapy treatments on the same day by the same physiotherapist. The efficacy of the hyperinflation modes was measured by sputum wet weight. Secondary measures included compliance, tidal volume, airway pressure and PaO2/FiO2 ratio. There was no difference in wet weight of sputum cleared using ventilator hyperinflation or manual hyperinflation (mean 3.2 g, P=0.989). Further, no difference in compliance (P=0.823), tidal volume (P=0.219), heart rate (P=0.579), respiratory rate (P=0.929) or mean arterial pressure (P=0.593) was detected. A statistically significant difference was seen in mean airway pressure (P=0.002) between techniques. The effect of techniques on the PaO2/FiO2 response ratio was dependent on time (interaction P=0.024). Physiotherapy using ventilator hyperinflation cleared a comparable amount of sputum and was as safe as manual hyperinflation. This research describes a ventilator hyperinflation protocol that will serve as a platform for continued discussion, research and development of its application in ventilated patients.

Manual hyperinflation partly prevents reductions of functional residual capacity in cardiac surgical patients--a randomized controlled trial

INTRODUCTION

Cardiac surgery is associated with post-operative reductions of functional residual capacity (FRC). Manual hyperinflation (MH) aims to prevent airway plugging, and as such could prevent the reduction of FRC after surgery. The main purpose of this study was to determine the effect of MH on post-operative FRC of cardiac surgical patients.

METHODS

This was a randomized controlled trial of patients after elective coronary artery bypass graft and/or valve surgery admitted to the intensive care unit (ICU) of a university hospital. Patients were randomly assigned to a "routine MH group" (MH was performed within 30 minutes after admission to the ICU and every 6 hours thereafter, and before tracheal extubation), or a "control group" (MH was performed only if perceptible (audible) sputum was present in the larger airways causing problems with mechanical ventilation, or if oxygen saturation (SpO2) dropped below 92%). The primary endpoint was the reduction of FRC from the day before cardiac surgery to one, three, and five days after tracheal extubation. Secondary endpoints were SpO2 (at similar time points) and chest radiograph abnormalities, including atelectasis (at three days after tracheal extubation).

RESULTS

A total of 100 patients were enrolled. Patients in the routine MH group showed a decrease of FRC on the first post-operative day to 71% of the pre-operative value, versus 57% in the control group (P = 0.002). Differences in FRC became less prominent over time; differences between the two study groups were no longer statistically significant at Day 5. There were no differences in SpO2 between the study groups. Chest radiographs showed more abnormalities (merely atelectasis) in the control group compared to patients in the routine MH group (P = 0.002).

CONCLUSIONS

MH partly prevents the reduction of FRC in the first post-operative days after cardiac surgery.

TRIAL REGISTRATION

Netherlands Trial Register (NTR): NTR1384. http://www.trialregister.nl.

Comparison of flow rates produced by two frequently used manual hyperinflation circuits: a benchtop study

BACKGROUND

Manual hyperinflation is a treatment technique commonly used by physiotherapists in intensive care units to reverse or prevent atelectasis and mobilize airway secretions in intubated patients. The aim of this study was to determine which of the Magill (Rusch Manufacturing Ltd, Craigavon, UK) or Mapleson-C (CIG DF 655, CIG Medishield, Sydney, Australia) manual hyperinflation circuits was theoretically more effective at mobilizing secretions.

METHODS

A semi-blinded crossover study of 12 physiotherapists with tertiary level intensive care unit experience was conducted on a benchtop model. The order of circuits and compliance settings was randomized.

RESULTS

The Mapleson-C circuit produced a significantly faster peak expiratory flow (F[1, 210]=14.51, P < or = .01) and smaller inspiratory to expiratory flow ratio (F[1, 210]=28.44, P < or = .01) than the Magill circuit regardless of compliance settings.

CONCLUSION

The results of this study suggest that the Mapleson-C manual hyperinflation circuit may be more effective at mobilizing secretions.

Manual hyperinflation of intubated and mechanically ventilated patients in Dutch intensive care units--a survey into current practice and knowledge

BACKGROUND

In the daily bedside routine of the intensive care, potentially hazardous interventions that lack evidence need critical consideration. Therefore we examined current practice and knowledge of basic principles of manual hyperinflation (MH) in intubated and mechanically ventilated patients among intensive care unit nurses in the Netherlands.

METHODS

A written survey method was used, questionnaires were sent to ICU nurses specialised in mechanical ventilation in 115 Dutch hospitals. The questions related to following domains: (1) demographics; (2) use of MH; (3) presumed benefits; (4) essential elements of the MH procedure; (5) equipment and safety.

RESULTS

The response rate was 77%. From responding ICUs the majority (96%) stated they performed MH; 27% as a daily routine procedure, 69% performed MH on indication only. MH was mainly performed by ICU nurses. Half of ICUs reported to have a MH guideline available. Improved oxygenation and better removal of sputum were presumed benefits of MH. While slow inspiration and rapid expiration are considered to be essential elements of MH procedures, the majority of respondents stated to use rapid inspiration and slow expiration.

CONCLUSIONS

This survey indicates that MH is widely used as an important item of airway management. Importantly, there is no uniformity in the performance of the procedure. Before definitive research can be developed, standards for the MH procedure should be established.

Physiotherapy in intensive care is safe: an observational study

QUESTION

How often do adverse events (including adverse physiological changes) occur during physiotherapy intervention in intensive care?

DESIGN

A multi-centre prospective observational study.

PARTICIPANTS

Five tertiary level university-affiliated intensive care units.

OUTCOME MEASURES

All physiotherapy intervention in five intensive care units over a three month period. When certain specified changes occurred during physiotherapy intervention, details were noted including diagnosis of patient, intervention, vital signs, radiological changes, co-morbidities, chemical pathology, and fluid balance.

RESULTS

12 281 physiotherapy interventions were completed with 27 interventions resulting in adverse physiological changes (0.2%). This incidence was significantly lower than a previous study of adverse physiological changes (663 events in 247 patients over a 24-hour period); the incidence during physiotherapy intervention was lower than during general intensive care. Common factors in the patients who had an adverse physiological change were a deterioration in cardiovascular status (ie, decrease in blood pressure or arrhythmia) in patients on medium to high doses of inotropes/vasopressors, unstable baseline hemodynamic values, previous cardiac co-morbidities and intervention consisting of positive pressure or right side lying.

CONCLUSION

The incidence of adverse events during physiotherapy intervention in these five tertiary hospitals was low, demonstrating that physiotherapy intervention in intensive care is safe.

Outcomes research in the ICU: an aid in defining the role of physiotherapy

The economic reality of consumers, funders, and regulatory agencies demanding evidence regarding the quality of care patients are receiving in the intensive care unit (ICU) will have an effect on many of the routinely used practices in ICU, including physiotherapy. Outcomes research is a method that has been used to obtain evidence for the medical and respiratory management of patients in ICU. An overview of the literature was conducted to answer the following questions: 1. What is outcomes research? 2. Which outcomes should be measured in the adult critical care environment? 3. Which outcomes are physiotherapists currently including in research reports? Outcomes research is recognized by critical care specialists as a cost-effective method of determining what works in the real world. The value of physiologic measures is questioned, whereas the importance of patient centered, economic, and traditionally accepted outcome measures is increasingly being recognized. Most physiotherapy research reports still include physiologic measurements as the primary outcome of an intervention. Outcomes research provides researchers with the tools to define the role of the physiotherapist in the critical care environment. The outcomes measured must be relevant to patients, families, and funders.

The Mapleson C circuit clears more secretions than the Laerdal circuit during manual hyperinflation in mechanically-ventilated patients: a randomised cross-over trial

QUESTION

What is the effect of the Mapleson C circuit compared with the Laerdal circuit in removing secretions and improving ventilation and gas exchange during manual hyperinflation?

DESIGN

Prospective, randomised, cross-over trial.

PARTICIPANTS

Twenty patients from a tertiary-level intensive care unit who were being mechanically ventilated.

INTERVENTION

Manual hyperinflation in side-lying with both the Mapleson C or Laerdal circuit on the one day, one circuit in the morning and one in the afternoon, with a washout period of at least three hours between them.

OUTCOME MEASURES

Secretion clearance was measured as sputum weight, ventilation was measured as respiratory compliance and tidal volume, while gas exchange was measured as oxygenation and CO2 removal.

RESULTS

The Mapleson C circuit cleared 0.89 g (95% CI 0.80 to 1.15) more secretions than the Laerdal circuit (p < 0.02). There was no difference between the Mapleson C and the Laerdal circuits on respiratory compliance (p = 0.81), tidal volume (p = 0.45), oxygenation (p = 0.28), or CO2 removal (p = 0.17).

CONCLUSION

Although more secretions were cleared using the Mapleson C compared with the Laerdal circuit in this study, this had no consequence in terms of oxygenation and compliance only trended to improve. As the study was underpowered the clinical significance of these findings is not clear.

Pattern of ventilation during manual hyperinflation performed by physiotherapists

Summary The aim of this prospective observational study was to document patterns of ventilation during manual hyperinflation by physiotherapists. Manual hyperinflation with a Mapleson-F system was performed on the same patients on two consecutive days. Patterns of ventilation were recorded using a heated pneumotachometer, pressure transducer and custom designed data acquisition and analysis systems. The mean (SE) results were: inspiratory time 1.45 (0.10) s; volume delivered 1.23 (0.07) l; peak inspiratory and expiratory flow rate 1.51 (0.06) l.s(-1) and 3.26 (0.30) l.s(-1), respectively and I : E flow rate ratio 0.63 (0.05). All the physiotherapists achieved an increase in volume which was delivered within a safe and effective pressure range and without cardiovascular compromise. Most (26 out of 34 sessions) performed the technique in the way recommended for enhancing secretion clearance. This is the first study to document comprehensively the pattern of ventilation during manual hyperinflation and provides the basis for further clinical trials evaluating its effectiveness for secretion clearance and volume restoration.

Manual hyperinflation causes norepinephrine release

OBJECTIVE

To measure hemodynamics and plasma catecholamines during manual hyperinflation (MHI) in ventilated patients.

METHODS

MHI was performed with a Mapleson "C" circuit, 2l-reservoir bag; peak inspiratory pressure was standardized to 35 mL water; and positive expiratory-end pressure of 5 mL water was administered to seven mechanically ventilated patients with septic (6) and cardiogenic (1) shock (67.2 +/- 5.2 years, Acute Physiology Assessment and Chronic Health Evaluation II score 22.1 +/- 3.1). Diastolic (DAP) and mean arterial pressure (MAP), continuous cardiac index, pulmonary artery occlusion pressure, dynamic compliance, plasma norepinephrine and epinephrine, and arterial blood gases were recorded, and systemic vascular resistance index (SVRI) and oxygenation ratio were calculated.

RESULTS

There were no significant changes in pulmonary artery occlusion pressure, mean arterial pressure, or PaO2/FiO2. There were significant increases in SVRI (P < .001), DAP (P < .001), dynamic compliance (P < .01), and plasma norepinephrine (P < .001) and a decrease in cardiac index (P < .05) after MHI.

CONCLUSIONS

The increases in DAP, SVRI, and plasma norepinephrine suggest a sympathetic vasoconstrictive response during the application of MHI.

Early physiotherapy in the respiratory intensive care unit

Physiotherapy is an integral part of the management of patients in respiratory intensive care units (RICUs). The most important aim in this area is to enhance the overall patient's functional capacity and to restore his/her respiratory and physical independence, thus decreasing the risks of bed rest associated complications. This article is a review of evidence-based effectiveness of weaning practices and physiotherapy treatment for patients with respiratory insufficiency in a RICU. Literature searches were performed using general and specialty databases with appropriate keywords. The evidence for applying a weaning process and physiotherapy techniques in these patients has been described according to their individual rationale and efficacy. The growing number of patients treated in RICUs all over the world makes this non pharmacological approach both welcome and interesting. However, to date, there are only strong recommendations concerning the evidence-based strategies to speed weaning. Early physiotherapy may be effective in ICU: however, most techniques (postures, limb exercise and percussion/vibration in particular) need to be further studied in a large population. Evidence supporting physiotherapy intervention is limited as there are no studies examining the specific effects of interventions on long-term outcome.

Effects of manual hyperinflation and suctioning in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia

Ventilator-associated pneumonia results from bacterial colonisation of the aerodigestive tract or aspiration of contaminated secretions into the lower airways. As a consequence of infection of the lung parenchyma and alveolitis, accumulation of inflammatory exudates and infiltration of airway mucosa can lead to unfavourable respiratory mechanics in ventilator-associated pneumonia. Tracheal suction is often employed by nursing staff in the management of mechanically ventilated patients with ventilator-associated pneumonia but this technique has the potential to increase respiratory resistance. Manual hyperinflation is used by physiotherapists to improve lung volume and mobilise secretions and has been shown to increase lung compliance. The effect of manual hyperinflation on airway resistance has not been studied. This study aims to demonstrate an additional mechanical benefit to the respiratory system when manual hyperinflation and suction techniques are combined, by comparing the application of manual hyperinflation and suction with suction alone on static lung compliance (C(L)) and inspiratory resistance (R(AW)) in mechanically ventilated patients with ventilator-associated pneumonia. Fifteen adult patients with ventilator-associated pneumonia were recruited and acted as their own controls. Manual hyperinflation followed by suction (manual hyperinflation plus suction) and suction alone were applied consecutively, in random order, on two occasions, four hours apart. Respiratory variables, C(L) and R(AW), were measured five times and the averaged value documented. Data were recorded before, immediately after, and 30 minutes after each intervention protocol. C(L) increased by 22% and R(AW) decreased by 21%, up to 30 minutes after manual hyperinflation plus suction, but not after suction alone. This study suggests that manual hyperinflation in conjunction with suction induces beneficial changes in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia.

The effect of positive end-expiratory pressure level on peak expiratory flow during manual hyperinflation

Including positive end-expiratory pressure (PEEP) in the manual resuscitation bag (MRB) may render manual hyperinflation (MHI) ineffective as a secretion maneuver technique in mechanically ventilated patients. In this study we aimed to determine the effect of increased PEEP or decreased compliance on peak expiratory flow rate (PEF) during MHI. A blinded, randomized study was performed on a lung simulator by 10 physiotherapists experienced in MHI and intensive care practice. PEEP levels of 0-15 cm H(2)O, compliance levels of 0.05 and 0.02 L/cm H(2)O, and MRB type were randomized. The Mapleson-C MRB generated significantly higher PEF (P < 0.01, d = 2.72) when compared with the Laerdal MRB for all levels of PEEP. In normal compliance (0.05 L/cm H(2)O) there was a significant decrease in PEF (P < 0.01, d = 1.45) for a PEEP more than 10 cm H(2)O in the Mapleson-C circuit. The Laerdal MRB at PEEP levels of more than 10 cm H(2)O did not generate a PEF that is theoretically capable of producing two-phase gas-liquid flow and, consequently, mobilizing pulmonary secretions. If MHI is indicated as a result of mucous plugging, the Mapleson-C MRB may be the most effective method of secretion mobilization.

The effect on expiratory flow rate of maintaining bag compression during manual hyperinflation

Operator performance during the expiratory phase of manual hyperinflation appears to vary between physiotherapists for Mapleson-B or C circuits. Some physiotherapists release the valve but maintain compression of the bag, whereas others release both the valve and the bag. The effect of this difference on peak expiratory flow rate (PEFR) has not been reported. The aim of this study was to document the effect of maintaining bag compression during expiration on PEFR and inspiratory to expiratory flow rate ratio (I:E). Six physiotherapists with experience using manual hyperinflation participated. A within-subjects repeated measures design was used. Subjects performed manual hyperinflation using a Mapleson-C circuit with 'rapid release', releasing the valve only, or releasing both the bag and the valve, during expiration in a test lung model. Inspiratory time was controlled using a metronome and flows were measured with a heated pneumotachometer. Maintaining bag compression significantly reduced PEFR (1.54 (0.08) vs 2.00 (0.07) l/sec, p = 0.008) and increased I:E flow rate ratio (0.65 (0.04) vs 0.50 (0.02), p = 0.02) for the Mapleson-C circuit at a 1.4 litre target volume. There were no significant differences for these measures between techniques when subjects emptied the bag. The effect needs to be confirmed in the clinical setting.

Head-down tilt and manual hyperinflation enhance sputum clearance in patients who are intubated and ventilated

The purpose of this prospective randomised cross-over study was to measure peak expiratory flow rates during manual hyperinflation and to determine if the addition of a head-down tilt to physiotherapy treatment increased sputum production in patients who are intubated and ventilated. Twenty patients who were intubated, ventilated and haemodynamically stable were randomised to a sequence of physiotherapy treatment in a flat side-lying or a head-down tilt position. Peak expiratory flow rates were measured for each breath during manual hyperinflation using a Vitalograph peak flow meter. Sputum wet weight was collected for each treatment position and static pulmonary compliance was measured before and immediately following physiotherapy treatment. There was a significant increase in peak expiratory flow (p < 0.001) and sputum production (p = 0.008) in the head-down tilt position. The mean difference and 95% confidence intervals for expiratory flow were 0.17 (0.15 to 0.19) l/sec and for the wet weight of sputum 1.97 (0.84 to 3.10) g. The peak expiratory flow rate was sufficient to produce annular flow in both flat side-lying (1.97 +/- 0.09) l/sec and in the head-down tilt position (2.14 +/- 0.08) l/sec. Static pulmonary compliance improved significantly following physiotherapy treatment (p = 0.003). The mean difference and 95% confidence intervals pre- and post-treatment for static pulmonary compliance were 5.18 (2.14 to 8.22) ml/cmH(2)O. The results suggest that addition of a head-down tilt to physiotherapy treatment, including manual hyperinflation, in patients who are intubated and ventilated, increases sputum production and improves peak expiratory flow.

The effect of circuit type, volume delivered and "rapid release" on flow rates during manual hyperinflation

Traditionally, manual hyperinflation has been performed using "rapid release" to promote a fast peak expiratory flow rate (PEFR) but rapid release has not been described. In addition, it has been demonstrated that different resuscitation circuits provide varying degrees of resistance to expiratory flow and it is known that a variety of circuits are used in Australia for manual hyperinflation. The aim of this study was to document current practice, the effect of rapid release, controlling inspiration, different volumes and circuit type on flow rates, and the inspiratory to expiratory flow rate (I:E) ratio during manual hyperinflation. Using a test lung model, 15 physiotherapists performed 11 trials using the Air Viva 2, a Mapleson-C and a Mapleson-F circuit, both with and without rapid release, and delivering two volumes. The order of the trials was randomised. Rapid release produced a faster PEFR irrespective of circuit type or volume delivered. The effect of rapid release, and the absolute PEFR, was less for the Air Viva 2 compared with the Mapleson circuits. Expiratory flow rate was faster for the larger volume. The theoretically optimal I:E ratio to move secretions was achieved delivering the lower target volume with the Mapleson circuits and using rapid release.

The effects of three manual hyperinflation techniques on pattern of ventilation in a test lung model

Manual hyperinflation (MHI) is used by physiotherapists as a treatment technique in intubated patients. This study investigated the effect of three different MHI techniques using a Mapleson-C circuit configuration with a CIG Medishield valve on volume delivered (Vt), peak inspiratory (PIFR) and expiratory flow rates (PEFR), and peak airway pressure (PAP) in a test lung model. The protocols differed in the degree of valve closure and inclusion of an inspiratory pause. For protocols 1, 2 and 3 the measures were Vt-1.33 (0.21), 2.74 (0.13), 3.55 (0.12) litres; PAP-14.30 (0.82), 24.00 (0.47), 30.20 (0.92) cmH2O and PIFR-1.13 (0.05), 1.51 (0.15), 1.32 (0.09) l/s respectively. All pair comparisons were statistically significant except for PEFR (l/s), which was significantly lower for protocol 1 [1.62 (0.06)], compared to protocols 2 [2.01 (0.25)] and 3 [2.10 (0.19)] but not between protocols 2 and 3. Circuit and technique choice should be considered in relation to the specific therapeutic aim of treatment.

Manual hyperinflation: consistency and modification of the technique by physiotherapists

BACKGROUND AND PURPOSE

The present study aimed to evaluate the consistency with which physiotherapists apply manual hyperinflation to a test lung using the Air-Viva-2 or Mapleson-B resuscitation circuit, and their ability to modify the technique as pulmonary characteristics change.

METHOD

A quasi-experimental, randomized, repeated-measures design was used to study 16 volunteer physiotherapists performing manual hyperinflation to a test lung simulating three clinical situations. Each subject applied manual hyperinflation to the test lung for each simulation three times in one day using the resuscitation circuit that they would normally use in their clinical practice. Eight subjects used the Air-Viva-2 circuit and eight used the Mapleson-B circuit. Measurements of tidal volume (Vp), peak airway pressure (Paw) and fraction of delivered oxygen (FDO2) were recorded during each testing period. Inflation rate and minute volume were calculated.

RESULTS

As compliance decreased and airway resistance increased, VT decreased and Paw increased. Of the eight subjects using the Air-Viva-2 circuit, only three subjects delivered greater than 0.80 FDO2. All subjects using the Mapleson-B circuit delivered greater than 0.85 FDO2.

CONCLUSIONS

Subjects demonstrated good consistency in the application of manual hyperinflation for all three simulations and modified their technique appropriately as simulated pulmonary characteristics changed.

The use of a pressure manometer enhances student physiotherapists' performance during manual hyperinflation

The purpose of this study was to determine the effect of using a pressure manometer on the delivery of target airway pressures during manual hyperinflation by student physiotherapists in the laboratory and clinical environments. Manual hyperinflations were delivered under control and feedback conditions where the feedback condition involved manual hyperinflation with a pressure manometer. Compared with control conditions, the availability of a manometer significantly decreased the mean absolute error (9.5 +/- 0.9 cm H2O to 1.4 +/- 0.2 cm H2O) and mean variable error (2.2 +/- 0.3 cm H2O to 1.3 +/- 0.1cm H2O) of peak airway pressures during manual hyperinflation. In addition, the availability of a manometer negated the influence of environment on accuracy. Therefore, the availability of a pressure manometer provided an effective clinical tool that was easily used to provide feedback regarding the peak airway pressures delivered during manual hyperinflation.

Manual hyperinflation--effects on respiratory parameters

BACKGROUND AND PURPOSE

Manual hyperinflation (MH) of the lungs is commonly used by physiotherapists in the treatment of intubated mechanically ventilated patients with the aim of increasing alveolar oxygenation, reversing atelectasis or mobilizing pulmonary secretions. However, the efficacy of MH, used in isolation, has not been clearly established.

METHOD

This randomized, controlled trial investigated the effects of MH on lung compliance (CL), the arterial oxygen to fraction of inspired oxygen ratio (PaO2:FIO2) and the alveolar-arterial oxygen tension difference (A-a)PO2 in 100 medically stable, mechanically ventilated subjects who had undergone coronary artery surgery (CAS). Post-CAS subjects were used for this study as they constitute a large, homogeneous and accessible group. Subjects were randomized to either a control group (non-MH group) or to a treatment group (MH group) which received MH within four hours of surgery.

RESULTS

After four minutes of MH there were significant improvements in CL, PaO2:FIO2 and (A-a)PO2 with values remaining above baseline measures at 60 min post-intervention. The mean improvement in CL was 6 ml/cmH2O (approximately 15%), 56 mmHg for PaO2:FIO2 (approximately 17%) and 29 mmHg for (A-a)PO2 (approximately 17%) immediately post-intervention. No significant changes in mean CL, PaO2:FIO2 or (A-a)PO2 were seen in the non-MH group.

CONCLUSIONS

MH performed in the stable ventilated patient significantly increased CL and PaO2:FIO2 and decreased (A-a)PO2, but the clinical significance of this improvement is unclear. Further investigations are required to validate the findings of this study as well as to determine the therapeutic value of MH on patient outcome.