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

Automated Inflating Resuscitator (AIR): Design and Development of a 3D-Printed Ventilator Prototype and Corresponding Simulation Scenario Based on the Management of a Critical COVID-19 Patient

Recent surges in COVID-19 cases have generated an urgent global demand for ventilators. This demand has led to the development of numerous low-cost ventilation devices, but there has been less emphasis on training health professionals to use these new devices safely. The aim of this technical report is twofold: first, to describe the design and manufacturing process of the automated inflating resuscitator (AIR), a 3D-printed ventilator training device which operates on the principle of pushing a bag valve mask; second, to present a simulation scenario that can be used for training health professionals how to use this and similar, low-cost, 3D-printed ventilators in the context of ventilator shortages caused by COVID-19. To this end, the AIR was designed in an expedient manner in accordance with basic functionality established by the Medicines and Healthcare Products Regulatory Agency (United Kingdom) for provisional clinical use in light of COVID-19.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Artificial ventilation during transport: A randomized crossover study of manual resuscitators with comparison to mechanical ventilators in a simulation model

BACKGROUND

Positive-pressure ventilation in critically ill patients is commonly administered via a manual resuscitation device or a mechanical ventilator during transport. Our group previously compared delivered ventilation parameters between a self-inflating resuscitator and a flow-inflating resuscitator during simulated in-hospital pediatric transport. However, unequal group access to inline pressure manometry may have biased our results. In this study, we examined the performance of the self-inflating resuscitator and the flow-inflating resuscitator, both equipped with inline manometry, and several mechanical ventilators to deliver prescribed ventilation parameters during simulated pediatric transport.

METHODS

Thirty anesthesia providers were randomized to initial resuscitator device used to hand ventilate a test lung. The resuscitators studied were a Jackson-Rees circuit (flow-inflating resuscitator) or a Laerdal pediatric silicone resuscitator (self-inflating resuscitator), both employing manometers. The scenario was repeated using several mechanical transport ventilators (Hamilton-T1, LTV^® 1000, and LTV^® 1200). The primary outcome was the proportion of total breaths delivered within the predefined target PIP/PEEP range (30 ± 3, 10 ± 3 cm H₂ O).

RESULTS

The Hamilton-T1 outperformed the other ventilators for breaths in the recommended range (χ²  = 2284, df = 2, P < .001) and with no breaths in the unacceptable range (χ²  = 2333, df = 2, P < .001). Hamilton-T1 also outperformed all human providers in proportion of delivered acceptable and unacceptable breaths (χ²  = 4540, df = 3, P < .001 and χ²  = 639, df = 3, P < .001, respectively). Compared with the flow-inflating resuscitator, the self-inflating resuscitator was associated with greater odds of breaths falling outside the recommended range (Odds ratio (95% CI): 1.81 (1.51-2.17)) or unacceptable (Odds ratio (95% CI): 1.63 (1.48-1.81)).

CONCLUSION

This study demonstrates that a majority of breaths delivered by manual resuscitation device fall outside of target range regardless of provider experience or device type. The mechanical ventilator (Hamilton-T1) outperforms the other positive-pressure ventilation methods with respect to delivery of important ventilation parameters. In contrast, 100% of breaths delivered by the LTV 1200 were deemed unacceptable.

Respiratory physiotherapy in intensive care unit: Bibliographic review

INTRODUCTION AND AIMS

Patients in intensive care unit are susceptible to complications due to different causes (underlying disease, immobilisation, infection risk…) The current main intervention in order to prevent these complications is respiratory physiotherapy, a common practice for nurses on a daily basis. Therefore, we decided to carry out this bibliographic review to describe the most efficient respiratory physiotherapy methods for the prevention and treatment of lung complications in patients in intensive care, taking into account the differences between intubated and non-intubated patients.

METHODOLOGY

The bibliographic narrative review was carried out on literature available in Pubmed, Cinahl and Cochrane Library. The established limits were language, evidence over the last 15 years and age.

RESULTS

Techniques involving lung expansion, cough, vibration, percussion, postural drainage, incentive inspirometry and oscillatory and non-oscillatory systems are controversial regarding their efficacy as respiratory physiotherapy methods. However, non-invasive mechanical ventilation shows clear benefits. In the case of intubated patients, manual hyperinflation and secretion aspirations are highly efficient methods for the prevention of the potential complications mentioned above. In this case, other RP methods showed no clear efficiency when used individually.

DISCUSSION AND CONCLUSIONS

Non-invasive mechanical ventilation (for non-intubated patients) and manual hyperinflation (for intubated patients) proved to be the respiratory physiotherapy methods with the best results. The other techniques are more controversial and the results are not so clear. In both types of patients this literature review suggests that combined therapy is the most efficient.

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.

Guideline implementation powered by feedback and education improves manual hyperinflation performance

AIM

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

RELEVANCE TO CLINICAL PRACTICE

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

Hiperinsuflação manual: revisão de evidências técnicas e clínicas

INTRODUÇÃO: A técnica de hiperinsuflação manual (HM), também conhecida como "bag squeezing" ou "bagging", foi inicialmente descrita como um recurso para melhorar a oxigenação pré e pós-aspiração traqueal, mobilizar o excesso de secreção brônquica e reexpandir áreas pulmonares colapsadas. OBJETIVO: Apresentar evidências científicas sobre os efeitos da manobra de HM como recurso fisioterapêutico, bem como suas indicações clínicas. MATERIAIS E MÉTODOS: Realizou-se uma busca nas bases de dados eletrônicas SciELO, ScienceDirect, PubMed e PEDro, utilizando-se os descritores "hiperinsuflação manual" (manual hyperinflation) e "fisioterapia" (physiotherapy). Como critério de inclusão considerou-se: conter os descritores no título ou resumo; ensaios clínicos que abordassem "hiperinsuflação manual" e fisioterapia; textos em inglês e português; publicações entre 1994 e 2011. RESULTADOS: Foram selecionados 25 estudos e todos apontaram a importância dessa manobra na mobilização de secreções traqueobrônquicas e para reexpansão de alvéolos colapsados, devido à melhora do volume pulmonar. Adequação das trocas gasosas, melhora da oxigenação e da complacência pulmonar, prevenção e tratamento de atelectasias são outras indicações. Também é consensual a preocupação com a padronização na aplicação da técnica. Melhores resultados são alcançados quando o volume aplicado é cerca de 50% maior que o volume corrente do paciente. Precauções quanto a limites de pressão em torno de 40 cm H2O, para se evitar barotraumas, também são referidas pela maioria dos estudos. CONCLUSÃO: A literatura traz evidências que sustentam a indicação do HM para mobilização e eliminação de secreções traqueobrônquicas e prevenção de infecções/complicações, além da necessidade de padronização da técnica.

Fatores que afetam a ventilação com o reanimador manual autoinflável: uma revisão sistemática

OBJETIVO: O reanimador manual autoinflável é um dispositivo que fornece ventilação com pressão positiva. Pesquisas mostram que, apesar da padronização dos reanimadores manuais autoinfláveis pela American Society for Testing and Materials, diversos fatores afetam o desempenho da ventilação, porém, os resultados são conflitantes. O objetivo desse estudo foi verificar as evidências dos fatores que influenciam a ventilação pulmonar com reanimadores manuais infantil/adulto por meio de uma revisão sistemática da literatura. FONTES DE DADOS: Foram incluídos artigos indexados nas bases Medline, Lilacs e SciELO publicados entre janeiro de 1986 e março de 2011. Utilizaram-se as palavras-chaves: "reanimador manual", "ressuscitador manual", "ventilação manual", "ventilação com pressão positiva", em inglês e português, além de "bag-valve". SÍNTESE DOS DADOS: Foram selecionados 45 artigos, sendo a maioria experimental. Os trabalhos compararam os reanimadores manuais por marcas, modelos e analisaram as características dos profissionais que os utilizam. Estudos verificaram que a eficácia da ventilação com os reanimadores manuais depende da marca, modelo e características funcionais do aparelho utilizado, assim como formação, treinamento e experiência do profissional que os manipula. Outros fatores que podem influenciar são a forma de compressão dos reanimadores manuais, o uso da válvula limitadora de pressão e o fluxo de oxigênio fornecido aos aparelhos. CONCLUSÕES: A variabilidade nos parâmetros ventilatórios fornecidos durante a ventilação com reanimadores manuais não permite uniformizar a técnica, o que prejudica a reanimação cardiopulmonar. Apesar da maioria dos reanimadores manuais parecer estar de acordo com padrões internacionais, os equipamentos devem ser avaliados antes de utilizados no ambiente clínico. Pouco se sabe sobre os modelos pediátricos e neonatais.

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.

Physiotherapy for adult patients with critical illness: recommendations of the European Respiratory Society and European Society of Intensive Care Medicine Task Force on Physiotherapy for Critically Ill Patients

The Task Force reviewed and discussed the available literature on the effectiveness of physiotherapy for acute and chronic critically ill adult patients. Evidence from randomized controlled trials or meta-analyses was limited and most of the recommendations were level C (evidence from uncontrolled or nonrandomized trials, or from observational studies) and D (expert opinion). However, the following evidence-based targets for physiotherapy were identified: deconditioning, impaired airway clearance, atelectasis, intubation avoidance, and weaning failure. Discrepancies and lack of data on the efficacy of physiotherapy in clinical trials support the need to identify guidelines for physiotherapy assessments, in particular to identify patient characteristics that enable treatments to be prescribed and modified on an individual basis. There is a need to standardize pathways for clinical decision-making and education, to define the professional profile of physiotherapists, and increase the awareness of the benefits of prevention and treatment of immobility and deconditioning for critically ill adult patients.

Manual hyperinflation improves alveolar recruitment in difficult-to-wean patients

STUDY OBJECTIVES

To investigate the effect of manual hyperinflation (MH) in patients with atelectasis associated with ventilation support.

DESIGN

Patients were randomized to either an experimental group or a control group.

SETTING

Pulmonary ICUs from two hospitals.

PATIENTS

Twenty-three patients with atelectasis associated with ventilation support.

INTERVENTIONS

The MH technique was at a rate of 8 to 13 breaths/min for a period of 20 min each session, three times per day for 5 days. The control group received their standard prescribed mechanical ventilation without supplemental MH. Sputum contents (wet/dry weight ratio, viscosity), respiratory system capacity (spontaneous tidal volume [Vt], maximal inspiratory pressure, rapid shallow breathing index [f/Vt], chest radiograph signs, and Pa(O2)/fraction of inspired oxygen [Fi(O2)]) were measured just prior to the MH at day 0 as baseline, and at day 3 and day 6 of the study.

MEASUREMENTS AND RESULTS

There were significant improvements in scores over the 6-day study in the experimental group compared to the control group in spontaneous Vt (p = 0.035) and chest radiograph signs (p = 0.040), and a trend toward improvement of f/Vt (p = 0.066) and Pa(O2)/Fi(O2) (p = 0.061) after adjustment for covariates. Other outcome variables did not differ significantly between the experimental and control groups.

CONCLUSIONS

MH performed on patients with atelectasis from ventilation support significantly improved alveolar recruitment.

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.

Feedback withdrawal and changing compliance during manual hyperinflation

BACKGROUND AND PURPOSE

The performance of manual hyperinflation by physiotherapists can be improved by the availability of a pressure manometer. The present study aimed to test whether these benefits could be maintained when the manometer is withdrawn and whether the availability of a manometer affects the pressures delivered under changing respiratory compliances.

METHOD

Manual hyperinflation breaths were delivered to a test lung by student physiotherapists, with a target peak airway pressure of 30 cm H2O under control, feedback and feedback-withdrawal conditions. The breaths were delivered for three trials under each testing condition at each of three respiratory compliance settings.

RESULTS

The availability of augmented feedback increased the accuracy and reduced the variability of performance; however, these improvements were not maintained when feedback was withdrawn. Changing respiratory compliance significantly affected the accuracy and variability during the control and withdrawal conditions, but the availability of a manometer negated these differences.

CONCLUSIONS

The availability of a pressure manometer negates the influence of respiratory compliance on the achievement of target peak airway pressures during manual hyperinflation in the laboratory environment, however these benefits are not retained when feedback is withdrawn. Therefore, it is recommended that a pressure manometer should be routinely available during manual hyperinflation in clinical practice to optimize treatment safety and effectiveness.