Ventilator hyperinflation: a survey of current physiotherapy practice in Australia and New Zealand.
Hyperinflation of the lungs is a technique commonly employed by
physiotherapists in the intensive care setting. Whilst there is
extensive evidence to support the use of manual hyperinflation, there is
limited evidence regarding the efficacy of ventilator hyperinflation.
The aim of this study was to investigate the current physiotherapy
practice of ventilator hyperinflation throughout Australia and New
Zealand. A purpose-designed postal survey was distributed to senior
physiotherapists in all intensive care units throughout Australia and
New Zealand (n=189). A response rate of 87% was obtained (n=165). A
minority of respondents (21%, n=35/165) performed ventilator
hyperinflation. A lack of training in ventilator hyperinflation was
cited as the main barrier to use (44%, n=46/105). Ventilator
hyperinflation was most commonly performed by a senior physiotherapist
in a tertiary intensive care unit. When performed, ventilator
hyperinflation was used as an alternative to manual hyperinflation, to
allow improved monitoring and control of ventilator parameters (74%,
n=25/34) and maintain positive end expiratory pressure (59%, n=20/34).
Ventilator hyperinflation is not commonly used by physiotherapists in
intensive care units throughout Australia and New Zealand and
considerable variability was found in its application between
respondents. Further studies are required to define optimal parameters
for ventilator hyperinflation and promote standardised delivery of this
Hayes K, Seller D, Webb M, Hodgson CL, Holland AE (2011): Ventilator hyperinflation: a survey of current physiotherapy practice in Australia and New Zealand. New Zealand Journal of Physiotherapy 39(3) 124-130.
Keywords: Physiotherapy, Survey, Lung Hyperinflation, Intensive Care
Therapeutics, Physiological (Surveys)
Hodgson, Carol L.
Holland, Anne E.
|Publication:||Name: New Zealand Journal of Physiotherapy Publisher: New Zealand Society of Physiotherapists Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2011 New Zealand Society of Physiotherapists ISSN: 0303-7193|
|Issue:||Date: Nov, 2011 Source Volume: 39 Source Issue: 3|
Hyperinflation of the lungs is a technique commonly employed by physiotherapists to treat atelectasis and secretion retention in the intensive care setting. Hyperinflation can be delivered by the ventilator by altering ventilation settings, or manually via a manual resuscitation circuit. The technique of manual hyperinflation (MHI) was first described in the literature in the 1960s (Clement and Hubsch 1968) and is commonly utilised by physiotherapists in the management of intubated patients throughout Australia and New Zealand (Denehy 1999, Hodgson et al 1999, Reeve et al 2008). The efficacy of MHI in reinflating collapsed alveoli, removing excess bronchial secretions and improving lung compliance and oxygenation has been well reported (Berney et al 2004, Choi and Jones 2005, Hodgson et al 2000, Maa et al 2005, Patman et al 2000, Stiller et al 1990). Furthermore, the technique used to deliver MHI has been well described in the literature (Hila et al 2002, Jones et al 1992, Maxwell and Ellis 2002, Maxwell and Ellis 2004, Maxwell and Ellis 2007, McCarren and Chow 1996, McCarren and Chow 1998, Patman et al 2001, Redfern et al 2001, Savian et al 2005). In contrast, the practice of ventilator hyperinflation (VHI) in intensive care units is not well described and there are currently no guidelines for its clinical application (Dennis et al 2010, Lemes et al 2009).
The deleterious effects from loss of positive end expiratory pressure (PEEP) on lung function and mechanics that occurs when patients are disconnected from the ventilator include a reduction in functional residual capacity, possible atelectrauma and a decrease in oxygenation (Amato et al 1998, Barker and Adams 2002, McCann et al 2001, Savian et al 2005). Ventilator hyperinflation involves manipulation of the ventilator settings to deliver larger than baseline tidal volumes, without the adverse effects of disconnection from the ventilator that are encountered with MHI. There are also a number of precautions and contraindications for MHI, such as baseline PEEP levels greater than 10cm[H.sub.2]O (Hodgson et al 1999, King and Morrell 1992) , its use in patients that are agitated or intolerant of manipulation of their artificial airway, or patients on inhaled nitric oxide. Ventilator hyperinflation may be a suitable alternative in these instances, as well as in circumstances where closer monitoring and control of ventilator parameters are desirable, such as cardiovascular instability and labile intracranial pressure.
One of the major safety considerations in performing hyperinflation is preventing barotrauma--with high peak airway pressures considered a contraindication to the technique (Hodgson et al 1999, King and Morrell 1992). A maximum peak airway pressure of 40cm[H.sub.2]O during MHI is recommended in the literature (Gammon et al 1992, Haake et al 1987, Rothen et al 1993) . There are currently no guidelines recommending safe peak airway pressures during VHI.
There is a paucity of studies examining the efficacy of VHI as a physiotherapy treatment. In a randomised crossover trial of 30 mechanically ventilated patients, VHI was more effective at clearing secretions and increasing static compliance than positioning in side lying alone (Lemes et al 2009). VHI has been compared to MHI, and the effects on sputum clearance, lung compliance and oxygenation have been found to be similar between the two techniques (Ahmed et al 2010, Berney and Denehy 2002, Savian et al 2006).
To facilitate further efficacy studies in this area, investigation of current practice is required to ensure that VHI techniques tested in future studies are relevant to clinical practice. A recent survey of VHI practice in 64 tertiary level ICUs within Australia (Dennis et al 2010) reported that 39% of respondents used VHI; however they did not investigate the use in other levels of ICU. This study described perceived indications and contraindications to the technique; however, it did not report how physiotherapists acquired the necessary skills to perform VHI, barriers to use, or the ventilatory parameters used to deliver VHI. The practice of VHI within New Zealand was reported in a conference abstract by Reeve et al (2008). This survey reported only one centre in New Zealand (5%) used the technique, but no details on how VHI was performed were provided.
The primary aim of the present study was to investigate current physiotherapy practice of VHI and identify barriers to use of the technique in all intensive care units throughout Australia and New Zealand. The secondary aim was to specifically describe the essential components of the technique, common dosage applications, how the skill is learned, and identify any variations in practice.
A purpose-designed postal survey was undertaken. Ethical permission for the study was granted by the human research ethics committee of the Alfred Hospital, Victoria, Australia.
The survey was addressed to the senior ICU physiotherapist of all identified intensive care units in Australia and New Zealand.
Materials and procedure
Intensive care units, in both public and private hospitals throughout Australia and New Zealand, were identified via the Australian and New Zealand Intensive Care Society CORE database (ANZICS-CORE). In Australia, this list of ICUs was cross-referenced with a list of hospitals--classified as a principal referral hospital, large major city or large regional/remote institution--in the Public Hospital Database obtained from the Australian Hospital Statistics report (Australian Institute of Health and Welfare 2009). Within New Zealand, the ANZICS list of ICUs was cross-referenced with a list of hospitals obtained from the author of the previous survey of VHI in New Zealand (Reeve et al 2008). Any discrepancies were resolved via personal telephone communication with senior physiotherapy clinicians at the relevant hospitals.
As no validated tool currently existed to survey physiotherapy practice in the use of VHI, a questionnaire was designed for the purpose. The six page questionnaire comprised 20 questions. For ease of completion and analysis, the questionnaire was composed of predominantly closed questions and sought information about demographic characteristics of respondents, characteristics of the hospital and intensive care unit, information regarding frequency and indications for VHI, information specific to VHI technique and dosage, and finally how the technique was learned. Experts in the field, and previous similar surveys (Hodgson et al 1999, King and Morrell 1992) were used to develop a broad range of questions and ensure face, content and construct validity of the survey. A pilot study was conducted with groups of cardiorespiratory physiotherapists from two major Melbourne public hospitals. Comments on question design, ambiguities, structure, flow and content were sought and minor changes made. These sites were resurveyed with the final version and results were included in the final analysis.
The questionnaire was then posted to the 'Senior ICU Physiotherapist' of all identified hospitals throughout Australia and New Zealand, along with a stamped reply-paid envelope. They were instructed to complete one survey for each ICU in their facility to determine their individual practice of VHI along with general information pertaining to the use of VHI in their unit. Questionnaires were coded for the purpose of tracking responses and to allow follow-up of non-returned questionnaires. Codes were not used during analysis. A covering letter explained the purpose of the questionnaire, identified the researchers and assured confidentiality. Six weeks were allowed for return of the questionnaire and repeat questionnaires were sent by mail to non-responders after a follow-up telephone call. Return of the completed questionnaire was taken to represent informed consent.
All closed data were of the nominal/ordinal form and analysed using SPSS Version 17.0 for Windows using descriptive frequency analyses. Pearson's Chi-square test was used to determine if there was a significant difference between responses according to demographic characteristics. The level of significance was set at p < 0.05. Continuous data which were not normally distributed were reported as a median and range, with all other values given as means and standard deviations. Open data were analysed by content analysis and development of themes. Two of the authors independently reviewed the open data to ensure consensus on themes. Discrepancies were resolved by discussion between the two authors, with a third author available for consultation if consensus could not be reached.
A total of 190 questionnaires were distributed. One of the hospitals to which the questionnaire was distributed had no intensive care unit, and was therefore excluded giving a total valid number of questionnaires distributed of 189. A response rate of 87.3% (n=165) was obtained. The response rate to individual questions within the survey varied widely. Consequently, results are presented as a number and percentage of the total respondents to each question.
Characteristics and descriptive data of respondents
Demographic details, characteristics of ICUs and prevalence of VHI usage are shown in Table 1. The majority of respondents worked in a public hospital (n=120/165, 72.7%), with the remainder of respondents working in a private hospital (n=45/165, 27.3%). The level of experience and qualification of respondents is outlined in Table 2. Years of experience as a physiotherapist and years of experience in ICU varied widely amongst respondents; however, more than half of the respondents (n=89/163, 54.7%) had been qualified for over 9 years and had spent greater than 3 years working in ICU (n=121/162, 74.7%)(Table 2). Despite this high level of experience, the highest level of university education completed by the majority of respondents was a Bachelor of Physiotherapy degree (n=119/161, 74%). There was a significant association between years of ICU experience and level of ICU, with all respondents working in level 3 ICUs having more than 1 years ICU experience (p = 0.016).
Use of VHI and indications
A minority of respondents (n=35/165, 21%) reported that they performed the technique of VHI (Table 1). The main themes identified for not performing VHI were lack of training (n=46/105, 44%) and lack of medical approval (n=40/105, 38%)--see Figure 1. There was a significant association between use of VHI and the level of ICU (p = 0.007), with the majority of respondents that perform VHI working in a level 3 ICU (n=24/35, 69%). None of the level 1 ICU respondents (n=25) reported using VHI, with one of the main reasons being that they did not treat mechanically ventilated patients for any considerable period of time. There was a significant association between use of VHI and geographical location (p = 0.007), with VHI more likely to be performed in Victoria (n=14/35, 40%) than in other states of Australia or New Zealand (Table 1).
Of the 35 respondents who did perform VHI, 34 went on to provide further details relating to specifics of the technique. Medical approval was not required by the majority of respondents who performed VHI; however, these respondents reported seeking advice from medical colleagues in certain circumstances, such as medical instability (Table 3). Almost half of the respondents that perform VHI (n=16/34, 47%) did not have a written protocol guiding practice (Table 3). The different types of staff that were reported to perform VHI are shown in Figure 2, demonstrating that VHI is predominantly a physiotherapy technique performed by senior physiotherapists.
The most commonly cited indications for performing VHI were sputum retention (n=30/34, 88%) and atelectasis (n=24/34, 71%). When choosing VHI over MHI, the most commonly cited themes that influenced decision making were that VHI allowed increased monitoring and control of ventilator parameters (n=25/34, 74%) and that PEEP was maintained (n=20/34, 59%) during VHI.
VHI technique and dosage
The frequency that VHI was performed varied considerably amongst respondents, as did the responses relating to dosage (Table 3); however most (n=17/34, 50%) respondents chose a dosage of 5 to 10 breaths per set, and performed 3 to 4 sets of deep breaths during an average treatment (n=15/34, 44%). Specific details relating to VHI technique and how it was most commonly performed are outlined in Table 4. The majority of respondents (n=16/31, 52%) reported that they used the synchronised intermittent mandatory ventilation (SIMV) volume control mode to deliver VHI. The pressure control mode of SIMV was only used by n=4/31 (13%) of respondents whilst assist control was utilised the least (n=1/31 3%). A peak airway pressure of 40cm[H.sub.2]O during VHI was reported by the majority of respondents (n=14/27, 52%), with only one respondent reporting that they performed VHI to a peak pressure of 45cm[H.sub.2]O.
The majority of respondents that perform VHI did not alter their technique when treating patients with atelectasis versus sputum retention (n=22/34, 65%). Of those that did alter their technique (n=12), the most common theme was to add or increase the plateau time for atelectasis (n=7/12, 58%) or to manipulate the flow profile to enable an expiratory bias of at least 10% for sputum retention (n =4/12, 33%).
Acquisition of skills
Most (n=24/35, 69%) of the respondents who reported performing VHI reported that they were taught how to perform VHI at the bedside by a senior physiotherapist, whilst almost half of respondents reported that they had taught themselves how to perform VHI through reading of scientific literature (n=16/35, 46%). A minority of respondents learnt how to perform VHI at an undergraduate level (n=6/35, 17%) or at a postgraduate course (n=8/35, 23%).
The results from this study identified that VHI is not commonly performed by intensive care physiotherapists throughout Australia and New Zealand, with the main reasons cited as lack of training and lack of medical approval. When VHI is performed, it is most commonly administered by a senior physiotherapist working in a tertiary ICU (level 3), and it is more likely to be performed in Victoria than in other states of Australia or New Zealand. There are no published guidelines as to what constitutes effective treatment with VHI and this is reflected in the results of the survey, with a lack of consensus on the essential components of the technique and large variation reported for technique and dosage.
Only 21% (n=35/165) of respondents in this study reported using VHI. This result supports the findings of an earlier survey of VHI practice in Australian tertiary (level 3) ICUs (Dennis et al 2010). These authors reported that VHI was performed in 25/64 Australian tertiary ICUs as compared to 23/71 Australian level 3 ICUs cited in this study. Our study also demonstrated that VHI is performed in a moderate proportion of level 2 ICUs in Australia and New Zealand (11/35, 31%). The use of VHI in New Zealand, as reported in the survey by Reeve et al (2008) was minimal with only 1/25 (5.3%) reporting that they performed the technique, compared to our study that reported an increase to 3/25 (12%).
In contrast to the use of VHI found in this study, MHI is reported as being commonly used by ICU physiotherapists, with 91% of respondents using MHI in a survey of Australian teaching hospitals (Hodgson et al 1999), 89% in a survey of the United Kingdom (King and Morrell 1992), 100% in a follow up survey of the United Kingdom (Davies and Igo 2004) and 63% in a survey of New Zealand (Reeve et al 2008). Of note, most of the surveys investigating the use of MHI were not recent, and it is difficult to directly compare results as respondents came from different types of hospitals and the levels of ICU included in most of these studies is not clearly defined (Davies and Igo 2004, Hodgson et al 1999, King and Morrell 1992). The survey of New Zealand ICU physiotherapists by Reeve et al (2008) did include the same hospitals and levels of ICU as our study and showed that MHI was more prevalent in New Zealand than VHI. The low use of VHI reported in our study may be related to the technique being considered relatively new to the physiotherapy profession, with a paucity of studies investigating its efficacy, and the first study only being published in 2002 (Berney and Denehy 2002). Furthermore, the essential components of MHI technique have been well described in the literature (Clement and Hubsch 1968, Denehy 1999, Maxwell and Ellis 2007, McCarren and Chow 1996, Patman et al 2001), whereas there are no such guidelines for VHI.
Only 17% of respondents that performed VHI reported that they learnt the technique at an undergraduate level. This is consistent with the level of experience of respondents, with 39% having more than 12 years experience as a physiotherapist and the technique only being reported in the literature since 2002. Only a slightly higher number of respondents that performed VHI reported learning the technique at a postgraduate course (23%); however, this survey did not investigate availability of education in VHI. Instead, the technique of VHI was predominantly learned at the bedside from a senior physiotherapist (69%). In addition, almost half of the respondents that use VHI do not have any hospital protocol or guidelines for new staff to follow. This type of in-house teaching, with no standardisation across hospitals, may contribute to the wide variation in technique and dosage found in this study. Almost half of respondents (46%) that perform VHI reported that they taught themselves how to perform the technique through reading of scientific literature. As there are no clear guidelines in the literature, this necessitates an individual interpretation on how to perform VHI, which may result in both safety and efficacy issues.
There is considerable variation in VHI technique and dosage in the studies to date (Ahmed et al 2010, Berney and Denehy 2002, Lemes et al 2009, Savian et al 2006), including mode of ventilation in which VHI is performed, volumes and peak airway pressures, flow profiles, and dosages. This is consistent with the results of this survey, with a lack of consensus on the essential components of the technique and the dosage. Only a small number of respondents clearly described details pertaining to VHI technique (see Table 4). Differences in the performance of VHI, such as inspiratory flow rates, plateau time, peak pressures and volumes delivered, raise concerns about the efficacy of treatment and patient safety with regards to barotrauma and volutrauma.
The majority of respondents that reported performing VHI reported sputum retention (88%) and atelectasis (71%) as the main indications for use. This is consistent with the indications identified for MHI (Hodgson et al 1999, King and Morrell 1992). Currently, there is only one study that has investigated the effects of VHI compared to a control; this study found that ventilator hyperinflation performed in the pressure support mode was more effective at clearing secretions and improving static compliance than positioning alone (Lemes et al 2009). There are no studies that have investigated the efficacy of VHI in reversing atelectasis. In contrast, there are a number of studies that support the use of MHI in reinflating collapsed alveoli and clearing secretions (Berney et al 2004, Hodgson et al 2000, Maa et al 2005, Stiller et al 1990).
Most respondents did not alter their VHI technique when treating atelectasis versus sputum retention. The literature investigating MHI supports the use of an inspiratory hold with peak pressures at 40cmH20 when treating atelectasis (Maa et al 2005, Rothen et al 1993). For sputum clearance, the flow profile seems to be the crucial factor. Sputum clearance is thought to be related to annular two-phase gas-liquid flow, with a requirement of expiratory flow being at least 10% greater than inspiratory flow for effective secretion clearance (Denehy 1999, Kim et al 1986a, Kim et al 1987, Kim et al 1986b, Maxwell and Ellis 1998). Respondents that reported altering their VHI technique according to the specific clinical problem reported using the above strategies.
The effects of VHI and MHI on sputum clearance, lung compliance and oxygenation have been reported to be similar (Ahmed et al 2010, Berney and Denehy 2002, Savian et al 2006). If both methods of hyperinflation are equally effective, then risk versus benefit analysis may be helpful in deciding which technique to use in individual patients. The majority of respondents that reported performing VHI (59%) reported that maintenance of PEEP and improved monitoring and control of airway pressures (74%) were indications for choosing VHI over MHI. VHI also allows direct monitoring of delivered volumes, flow profiles, and measurement of lung compliance. This increased level of control and monitoring make VHI an attractive technique in terms of safety, efficacy and even research opportunities.
The response rate to this survey was 87% which is considered excellent given that postal surveys have an expected response rate of between 30 and 60% (Portney and Watkins 2000). Therefore it is likely that the results reflect the current practice of the population studied. Given this, and our inclusion of all ICUs throughout Australia and New Zealand, the results can be used as a guide for physiotherapists in these countries to compare their practice against those of other providers and as a relevant starting point for future studies investigating the efficacy of VHI as a physiotherapy intervention.
Although the present study aimed to survey current physiotherapy practice of VHI, it did not attempt to determine the quality or efficacy of practice. Furthermore, the study sought responses only from one respondent per intensive care unit and it is acknowledged that individual physiotherapists within a single unit may have responded differently. However, the survey was directed to the most senior physiotherapist working in the intensive care unit and they were encouraged to collaborate with colleagues regarding responses as appropriate. There is also no way to be certain that the survey was completed by the senior ICU physiotherapist. Of those respondents that performed VHI, we did not attempt to ascertain the types or availability of appropriate patients for VHI. As a result it is not possible to determine whether this affected the frequency at which VHI was performed. Although lack of training was identified as the main barrier to the use of VHI, this survey did not investigate current availability of training throughout Australia and New Zealand. There was a poor response rate to questions relating to description of VHI technique. Therefore, responses may not accurately represent those that perform VHI but did not answer this question. A postal survey was chosen over a telephone survey given the large geographical area and number of respondents; however, postal surveys are known to have a low response rate and questions may be misinterpreted and the depth of responses tends to be more limited than with other methods (Portney and Watkins 2000). The poor response to questions relating to VHI technique may have been enhanced by telephone follow up of these respondents.
This study will enable physiotherapists to compare their practice of VHI to other similar service providers and reflect on any differences in practice. It has highlighted the need for further research to define the essential components of the technique. A lack of training was identified as the main barrier to performing VHI, and further investigation is warranted to ascertain current need and availability of training and optimum delivery of training. In addition, further investigation is required into the efficacy of VHI in reversing atelectasis and secretion clearance.
This study has demonstrated that VHI is not commonly performed by ICU physiotherapists in Australia and New Zealand and there is marked variation in technique and dosage. A lack of training in VHI was identified as the main reason that VHI was not performed, and further investigation into current necessity and availability of training is required. When VHI is performed, it is more likely to be done by a senior physiotherapist in a level 3 ICU. It was not performed at all by physiotherapists working in a level 1 ICU. This study has highlighted the need for further investigation into safety and efficacy of different aspects of the technique. This will facilitate the development of a clear definition of VHI and a consensus on the important components of technique to guide best practice both nationally and internationally.
* VHI is not commonly used by physiotherapists in intensive care units throughout Australia and New Zealand and there is considerable variability in technique and dosage.
* VHI is most commonly performed by a senior physiotherapist in a tertiary level ICU (level 3).
* The main barrier to the use of VHI is lack of training in the technique. Further investigation is required to establish current training needs, and availability, optimum delivery and barriers to training.
* Future research is required to define optimal parameters for VHI and promote standardised delivery of this technique.
The authors wish to thank ANZICS for providing a list of Australian and New Zealand intensive care units and all of the clinicians for giving their valuable time in responding to this survey.
ADDRESS FOR CORRESPONDENCE TO
Kate Hayes, Physiotherapy Department, The Alfred Hospital, 55 Commercial Road, Melbourne, Victoria, Australia 3181. Telephone: 00613 9076 3450, Fax: 00613 9076 2702. Email: email@example.com
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Kate Hayes, BPhysio (Hons), MPhysio (Cardio), Senior Clinician Physiotherapist, Alfred Health, Melbourne, Australia
Daniel Seller, BPhysio (Hons), Senior Clinician Physiotherapist, St Vincents Hospital and Alfred Health, Melbourne, Australia
Melissa Webb, BPhysio, M.Health Science (Health Management), Senior Clinician Physiotherapist, Alfred Health, Melbourne, Australia
Carol L Hodgson, PhD, BAppSc(Physio), FACP, Senior Research Fellow, ANZICS-Research Centre, Monash University, Senior Clinician Physiotherapist Alfred Health, Melbourne, Australia
Anne E Holland, PhD, Associate Professor of Physiotherapy, La Trobe University and Alfred Health, Melbourne, Australia
Table 1: Characteristics of ICUs and use of VHI by geographical area Geographical Response ICU Number of beds area n (% of total) Median (range) Vic 31 (18.8%) 8 (3 - 31) NSW 50 (30.3%) 8 (2 - 54) QLD 33 (20%) 8 (3 - 30) Tas 4 (2.4%) 8 (6 - 10) WA 7 (4.2%) 12 (10 - 22) ACT 3 (1.8%) 8 (6 - 18) SA 10 (6.1%) 9.5 (3 - 24) NT 2 (1.2%) 6 (6 - 6) NZ 25 (15.2%) 6 (2 - 34) Total 165 8 (2 - 54) Geographical Level of ICU: (3 / 2 / 1) n (% of total) using area Number of responses VHI Vic 16 / 12 / 3 14 (8%) NSW 21 /19/7 9 (5%) QLD 16/11/6 3 (2%) Tas 3 / 1 / 0 2 (1%) WA 5 / 2 / 0 3 (2%) ACT 1 / 2 / 0 0 (0%) SA 8 / 1 / 1 1 (1%) NT 1 / 1 / 0 0 (0%) NZ 10 / 6 / 8 3 (2%) Total 81 / 55/25 35 (21%) Geographical Number of respondents using area VHI by ICU level (3 / 2 / 1) Vic 11 / 3 / 0 NSW 4 / 5 / 0 QLD 2 / 1 / 0 Tas 2 / 0 / 0 WA 3 / 0 / 0 ACT 0 / 0 / 0 SA 1 / 0 / 0 NT 0 / 0 / 0 NZ 1 / 2 / 0 Total 24 /11/0 ICU = Intensive Care Unit. VHI = Ventilator Hyperinflation. Vic = Victoria, NSW = New South Wales, QLD = Queensland, Tas = Tasmania, WA = Western Australia, ACT = Australian Capital Territory, SA = South Australia, NT = Northern Territory, NZ = New Zealand. Level of ICU defined by the Australian Institute of Health and Welfare. Table 2: Experience and qualifications of respondents Response n (% of total) Years since qualification < 1 year 0 (0%) (n = 163) 1-3 years 5 (3.1%) 3-6 years 37 (22.7%) 6-9 years 32 (19.6%) 9-12 years 26 (16%) > 12 years 63 (38.7%) Years of ICU experience < 1 year 9 (5.6%) (n = 162) 1-3 years 32 (19.8%) 3-6 years 43 (26.5%) 6-9 years 21 (13%) 9-12 years 25 (15.4%) > 12 years 32 (19.8%) Qualifications Diploma 11 (6.8%) (n = 161) Bachelor degree 119 (73.9%) Graduate diploma 9 (5.6%) Masters by 18 (11.2%) coursework Masters by research 0 Doctorate 2 (1.2%) Other 2 (1.2%) ICU = Intensive Care Unit. Table 3: Dosage and protocols for VHI Parameter Response n (% of respondents using VHI) Frequency of Less than once per month 11 (32.4%) VHI usage Less than once per week 7 (20.6%) More than once per week 9 (26.5%) Daily 7 (20.6%) Number of 1 - 2 1 (2.9%) breaths per set 3 - 4 9 (26.5%) 5 - 10 17 (50%) > 10 7 (20.6%) Number of sets 1 - 2 3 (8.8%) per treatment 3 - 4 15 (44.1%) 5 - 10 13 (38.2%) > 10 3 (8.8%) Medical Yes 4 (11.8%) Approval Required? No 26 (76.4%) Certain circumstances 4 (11.8%) Protocol for VHI Yes 18 (52.9%) No 16 (47.1%) Total 34 VHI = Ventilator Hyperinflation Table 4: Most commonly used parameters for ventilator hyperinflation Parameter Number of Most common responses response Mode of ventilation n = 31 SIMV/VC (n = 16, 52%) Respiratory rate (breaths n = 22 < 6 (n = 11, 50%) Peak airway pressure n = 27 40 (n = 14, 52%) (cm[H.sub.2]O) Peak volume n = 10 1.5 (n = 3, 30%) delivered (litres) Inspiratory flow n = 15 Yes (n = 12, 80%) rate altered? Inspiratory flow rate n = 8 20 (n = 3, 38%) (litres/minute) 30 (n = 3, 38%) Plateau n = 14 [less than or equal (seconds) to] < 2 (n = 9, 64%) Inspiratory time n = 16 5 (n = 7, 44%) (Ti) (seconds) Parameter Range Mode of ventilation Respiratory rate (breaths 3 - 15 Peak airway pressure 20 - 45 (cm[H.sub.2]O) Peak volume 0.5 - 2.0 delivered (litres) Inspiratory flow rate altered? Inspiratory flow rate (litres/minute) 20 - 40 Plateau 0.5 - 5 (seconds) Inspiratory time 1.5 - 5 (Ti) (seconds) SIMV/VC = synchronised intermittent mandatory ventilation/volume control mode Figure 1: Why ventilator hyperinflation is not performed. Reasons VHI not performed Lack of training 46 No medical approval 40 No indication 22 Prefer manual hyperinflation 12 Lack of resources 10 Lack of evidence 6 Number of respondents (n=105) VHI = ventilator hyperinflation Note: Table made from bar graph. Figure 2 : Who performs ventilator hyperinflation? Professional group Snr PT 34 Jnr PT 21 PT Student 11 Dr 6 NS 5 Number of respondents (n=34) Snr PT = senior physiotherapist, J nr PT = junior physiotherapist, PT student = student physiotherapist, Dr = medical colleague, NS = nursing staff Note: Table made from bar graph.
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