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

Bennett, Bradley G; Thomas, Peter J.; Ntoumenopoulos, George

doi:10.4187/respcare.04066

Cited by 7 publications

(4 citation statements)

References 31 publications

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“…Moreover, the shorter V T delivered in this study (mean of 643 mL) might explain why a T INSP shorter than two seconds (mean of 1.84 s) was able to generate an adequate expiratory flow bias. A recent bench study demonstrated that, to achieve sufficient expiratory flow bias during MH, it was necessary to have a T INSP of at least three seconds with normal compliance lungs and two seconds with lower compliance lungs [ 31 ]. However, in their study the delivered V T was standardized in 1.4 L which, clearly, required a longer T INSP to generate a lower PIF.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2018

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IntroductionManual 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.MethodsTwelve 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 (PIP), inspiratory time (TINSP), tidal volume (VT) and peak expiratory flow (PEF) were measured continuously.ResultsIt was found that MH performed post-instruction delivered a smaller VT (643.1 ± 57.8 ml) at a lower PIP (15.0 ± 1.5 cmH2O), lower PIF (38.0 ± 9.6 L/min), longer TINSP (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.ConclusionsPerformance 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.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2018

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“…8 cmH2O) to reduce excess pressure being applied, increasing sleep efficiency while preventing overdistension of the lung tissue. APAP devices are the most complex, with automatic PEEP adjustments performed on a breath-by-breath basis from additional inline and auditory sensor measurements to detect periods without breathing [18] . Adjustments between clinician-set boundaries of 4–20 cmH2O are performed through algorithms based on the detection of inspiratory flow limitation, snoring, apnea events, and obstructive pressure in device sensor measurements [12] .…”

Section: Hardware In Contextmentioning

confidence: 99%

“…A Michigan Instruments Training and Testing Mechanical Lung (Michigan, USA) was used to validate the mePAP with ‘breaths’ of known and controlled compliance and tidal volume. The lung was set to a compliance of 0.05 L/cmH2O to simulate a normal adult’s lung [18] .…”

Section: Validation and Characterisationmentioning

confidence: 99%

Design, manufacture, and control of a low-cost positive airway pressure device

Hill,

Jackson,

Uluilelata

et al. 2024

HardwareX

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“…The studies conducted in the United Kingdom have reported that 32% of the physiothearpists used MHI without a manometer and 41% with a manometer [ 17 ]. An Australian study reported that 31% of physiotherapists used a manometer and 51% set PIP < 40cmH 2 O [ 18 ]. This study further reported that a high PEFR is obtained by the slow squeeze during inspiration and quick release during expiration in manual hyperinflation.…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%

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

Liyanage,

Dassanayaka,

Chellapillai

et al. 2024

PLoS ONE

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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.

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

Cited by 7 publications

References 31 publications

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

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

Design, manufacture, and control of a low-cost positive airway pressure device

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

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