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

Ventilator hyperinflation - what settings generate an expiratory flow rate bias?

OBJECTIVES

To determine which mechanical ventilation settings influence the attainment of expiratory flow rate characteristics that may promote secretion mobilisation during ventilator hyperinflation (VHI).

DESIGN

Prospective, single centre study.

SETTING

Intensive care unit, tertiary metropolitan hospital.

PARTICIPANTS

Twenty-four patients receiving mechanical ventilation.

INTERVENTIONS

Patients were recruited to either a low PEEP or high PEEP group (5-9 cmH₂O or 10-15 cmH₂O PEEP respectively). Each group had three hyperinflation protocols applied.

MAIN OUTCOME MEASURES

Peak inspiratory flow rates (PIFR) and peak expiratory flow rates (PEFR) were measured and reported as PIFR/PEFR of less than or equal to 0.9; a PEFR-PIFR greater than or equal to 33 L/min; and PEFR greater than or equal to 40 L/min.

RESULTS

In both the low and high PEEP groups, VHI protocols using volume-controlled ventilation were significantly better at generating expiratory flow rate bias compared to pressure-controlled or Pressure Support ventilation. An expiratory flow rate bias was also achieved when VHI was performed in volume-controlled ventilation with either a peak inspiratory pressure target of 35 cmH₂O or a driving pressure of 20 cmH₂O. Median heart rate and blood pressure values did not change during VHI, but transient reductions in blood pressure were present in six participants (25%).

CONCLUSIONS

VHI performed using volume-controlled ventilation was more effective than pressure-controlled or Pressure Support ventilation to generate an expiratory flow rate bias.

CONTRIBUTION OF THE PAPER

Mechanical ventilator settings can be altered to perform hyperinflation and achieve expiratory flow rate properties that may increase the mobilisation of airway secretions. The results demonstrate that to achieve these properties.

Effects of ventilator hyperinflation on pulmonary function and secretion clearance in adults receiving mechanical ventilation: A systematic review with meta-analysis

INTRODUCTION

It is important to clarify the effect of ventilator hyperinflation(VHI) on pulmonary function and secretion clearance in adults receiving mechanical ventilation(MV). There is no published meta-analysis on the effects VHI on pulmonary function and secretion clearance in adults receiving MV. Objective Analyze the published randomized clinical trials(RCTs) that investigated the effects of VHI on pulmonary function and secretion clearance in adults receiving MV, comparing VHI with isolated aspiration, VHI with manual hyperinflation(MHI), VHI +vibrocompression(VB) versus VB and VHI+VB versus isolated aspiration.

METHODS

The following databases PubMed, LILACS, EMBASE, SciELO, PEDro database and Cochrane Central Register of Controlled Trials (CENTRAL) were consulted up to December 2021. Secretion clearance, static and dynamic compliance of the respiratory system(Cstat and Cdyn), airway resistance(Raw) and oxygenation outcomes were evaluated.

RESULTS

Thirteen studies met the study criteria, but only 12 studies were included on meta-analysis. There was no difference between VHI versus isolated aspiration for amount of secretions removed(0.41 SMD; 95% CI: -0.08 to 0.89; n=270), VHI versus MHI(0.51 grams; 95% CI: -0.08 to 1.11; n=256), VHI+VB versus VB(0.31 grams; 95% CI: -0.42 to 1.05; n=130) and VHI+VB versus isolated aspiration(0.54 grams; 95% CI: -0.06 to 1.14; n=132). There was difference for VHI versus isolated aspiration to Cstat (4.77 ml/cm H₂O; 95% CI: 2.41 to 7.14; n= 136).

CONCLUSION

No evidence was found that VHI was effective in increasing the amount of secretions removed, Cdyn and oxygenation, but VHI seems to show a slight improvement in Cstat when compared to isolated aspiration.

Rapid chest compression effects on intracranial pressure in patients with acute cerebral injury

BACKGROUND

Patients with acute brain injury often require invasive mechanical ventilation, increasing the risk of developing complications such as respiratory secretions retention. Rapid chest compression is a manual chest physiotherapy technique that aims to improve clearance of secretions in these patients. However, the rapid chest compression technique has been suggested to be associated with increased intracranial pressure in patients with acute brain injury. The aim of this work is to elucidate the effects of the technique on intracranial pressure in mechanically ventilated patients with acute brain injury. Furthermore, the effects of the technique in different volumes and flows recorded by the ventilator and the relationship between the pressure applied in the intervention group and the different variables will also be studied.

METHODS

Randomized clinical trial, double-blinded. Patients with acute brain injury on invasive mechanical ventilation > 48 h will be included and randomized in two groups. In the control group, a technique of passive hallux mobilization will be applied, and in the intervention group, it will be performed using the rapid chest compression technique. Intracranial pressure (main variable) will be collected with an intracranial pressure monitoring system placed at the lateral ventricles (Integra Camino).

DISCUSSION

The safety of chest physiotherapy techniques in patients at risk of intracranial hyperpressure is still uncertain. The aim of this study is to identify if the rapid manual chest compression technique is safe in ventilated patients with acute brain injury.

TRIAL REGISTRATION

NCT03609866 . Registered on 08/01/2018.

Effects of Mechanical Insufflation-Exsufflation on Sputum Volume in Mechanically Ventilated Critically Ill Subjects

BACKGROUND

Mechanical insufflation-exsufflation (MI-E) is a noninvasive technique performed to simulate cough and remove sputum from proximal airways. To date, the effects of MI-E on critically ill patients on invasive mechanical ventilation are not fully elucidated. In this randomized crossover trial, we evaluated the efficacy and safety of MI-E combined to expiratory rib cage compressions (ERCC).

METHODS

Twenty-six consecutive subjects who were sedated, intubated, and on mechanical ventilation > 48 h were randomized to perform 2 sessions of ERCC with or without additional MI-E before tracheal suctioning in a 24-h period. The primary outcome was sputum volume following each procedure. Secondary end points included effects on respiratory mechanics, hemodynamics, and safety.

RESULTS

In comparison to ERCC alone, median (interquartile range) sputum volume cleared was significantly higher during ERCC+MI-E (0.42 [0-1.39] mL vs 2.29 [1-4.67] mL, P < .001). The mean ± SD respiratory compliance improved in both groups immediately after the treatment, with the greater improvement in the ERCC+MI-E group (54.7 ± 24.1 mL/cm H₂O vs 73.7 ± 35.8 mL/cm H₂O, P < .001). Differences between the groups were not significant (P = .057). Heart rate increased significantly in both groups immediately after each intervention (P < .05). Additionally, a significant increase in oxygenation was observed from baseline to 1 h post-intervention in the ERCC+MI-E group (P < .05). Finally, several transitory hemodynamic variations occurred during both interventions, but these were nonsignificant and were considered clinically irrelevant.

CONCLUSIONS

In mechanically ventilated subjects, MI-E combined with ERCC increased the sputum volume cleared without causing clinically important hemodynamic changes or adverse events. (ClinicalTrials.gov registration: NCT03316079.).

Impacts in the Respiratory Mechanics of the Ventilator Hyperinsuflation in the Flow Bias Concept: a Narrative Review

AbstractPatients who require invasive ventilatory support are subject to the deleterious effects of this, mainly ventilator-associated pneumonia (VAP). The physiotherapist, a member of the multiprofessional team, assists the patient with the purpose of promoting the recovery and preservation of the functionality, being able to minimize / avoid secondary complications. This study aims to identify the repercussions of mechanical ventilation hyperinflation (MVH) in the flow bias concept in respiratory mechanics. This study is a narrative review. MVH is an important resource commonly used in clinical practice that involves the manipulation of mechanical ventilator configurations to provide larger pulmonary volumes, and the generated airflow gradient may play a relevant role in mucus transport, with the concept of flow bias the main factor responsible for its direction. For the mobilization of the mucus towards the cephalic direction to occur, there must be a predominant expiratory flow, guaranteeing the peak ratio of expiratory flow / inspiratory flow peak (EFP / IFP) greater than 1.11. Maintenance of mechanical ventilation assures the patient to maintain the positive end expiratory pressure (PEEP) and the oxygen inspired fraction, avoiding the deleterious effects of the mechanical ventilator disconnection. MVH is able to improve lung compliance without, however, increasing airway resistance. MVH in the cephalic flow bias concept is effective for the mucus mobilization in the central direction, being able to improve pulmonary compliance and peripheral oxygen saturation.Keywords: Respiration, Artificial. Intensive Care Units. Physical Therapy Department, Hospital.ResumoOs pacientes internados que necessitam de suporte ventilatório invasivo estão sujeitos aos efeitos deletérios deste, principalmente a pneumonia associada à ventilação mecânica (PAV). O fisioterapeuta, integrante da equipe multiprofissional, assiste o paciente com a finalidade de promover a recuperação e preservação da funcionalidade, podendo minimizar/evitar complicações secundárias. Este estudo consiste em identificar as repercussões da hiperinsuflação com ventilador mecânico (HVM) no conceito flow bias na mecânica respiratória. O presente estudo trata-se de uma revisão narrativa. A HVM é um importante recurso comumente utilizado na prática clínica que envolve a manipulação das configurações do ventilador mecânico para fornecer maiores volumes pulmonares, e o gradiente de fluxo de ar gerado pode desempenhar um papel relevante no transporte do muco, sendo o conceito de flow bias cefálico o principal fator responsável pelo direcionamento deste. Para que a mobilização do muco em direção cefálica ocorra, deve existir um fluxo expiratório predominante, garantindo a razão pico de fluxo expiratório/pico de fluxo inspiratório (PFE/PFI) maior do que 1,11. A manutenção da assistência ventilatória mecânica assegura ao paciente a manutenção da pressão positiva ao final da expiração (PEEP) e a fração inspirada de oxigênio (FiO2), evitando os efeitos deletérios da desconexão do ventilador mecânico. A HVM é capaz de melhorar a complacência pulmonar sem, no entanto, aumentar a resistência das vias aéreas. A HVM no conceito flow bias cefálico é eficaz para a mobilização do muco em direção central, sendo capaz de melhorar a complacência pulmonar e saturação periférica de oxigênio (SpO2).Palavras-chave: Respiração Artificial. Unidades de Terapia Intensiva. Serviço Hospitalar de Fisioterapia.

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.

Effect of manual chest wall compression in participants with chronic obstructive pulmonary disease

[Purpose] Pulmonary rehabilitation is appropriate for most individuals with chronic obstructive pulmonary disease (COPD). Pulmonary rehabilitation consists of conditioning and exercise therapy. Conditioning includes relaxation, breathing exercises, and manual chest wall compression during expiration (CWC). CWC improves the symptoms in individuals with respiratory disease who have undergone mechanical ventilation. However, evidence supporting the effectiveness of CWC for COPD has been insufficient. This study aimed to determine physiological responses to CWC in participants with COPD. [Participants and Methods] Twenty-nine participants with COPD were included in the study. Manual CWC techniques were performed in a comfortable position chosen by the participants (sitting, forward-leaning (sitting), or semi-Fowler’s). Ventilatory parameters, occlusion airway pressure (P_0.1), and dyspnea were assessed using a visual analog scale and were compared before and during CWC. [Results] During manual CWC, oxygen consumption, carbon dioxide production, end-tidal carbon dioxide concentration, and dyspnea were significantly decreased; however, P_0.1 was not affected. [Conclusion] Manual CWC for COPD had an immediate physiological effect, including a decrease in dyspnea that may have been facilitated by a reduced workload of the respiratory muscles. Thus, manual CWC may be effective for dyspnea by reducing oxygen consumption in the respiratory muscles.

Changes in ventilation mechanics during expiratory rib cage compression in healthy males

[Purpose] The purpose of this study was to clarify the differences in ventilation mechanics between quiet breathing and expiratory rib cage compression, and between expiratory rib cage compression on the upper rib cage and on the lower rib cage. [Subjects and Methods] Subjects comprised 6 healthy males. Expiratory rib cage compression was performed manually by compressing the upper and lower rib cages. Changes in the lung volume, flow rate, and esophageal and gastric pressure were examined. [Results] The end expiratory lung volume was significantly lower during expiratory rib cage compression than at rest, but the end inspiratory lung volume was not significantly different. When compared with the esophageal and gastric pressures on the upper and lower rib cages at rest, the gastric pressures were significantly higher at end expiration. Lung resistance was significantly higher during expiratory rib cage compression than at rest. [Conclusion] Although expiratory rib cage compression promoted expiration and increased tidal volume, the lung volume did not increase beyond end inspiratory levels at rest. Lung resistance may increase during expiratory rib cage compression due to a decrease in lung volume. The mechanism by which expiration is promoted differed between the upper and lower rib cages.

[Physiotherapy interventions in the ICU : Outcome-relevant measurement parameters]

BACKGROUND

Guidelines cannot provide differentiated recommendations for physiotherapy (PT) in intensive care medicine. Scientific publications for PT in the intensive care unit (ICU) usually only have low levels of evidence and often express safety and feasibility of PT in the ICU.

OBJECTIVE

Which measurement parameters are relevant for defining outcome and what interventions should one take into consideration?

MATERIALS AND METHODS

A literature review was conducted. This was based on a PubMed search with full text access, as well as specific definitions for physical therapy, intensive care and four out of seven conditions from the manual "Physiotherapy in intensive care".

RESULTS

The availability of 172 studies clearly shows that there is certainly PT research concerning the critical environment of the ICU. However, parameters for quantitative and qualitative detection of vigilance and state of consciousness as well as assessments to evaluate the mobility and the ability to help themselves are important for everyday use.

CONCLUSIONS

The difficulties of using PT in the ICU are not useful in ensuring the safety of the patient or performing a PT treatment. The conditions of the intensive care environment are not an obstacle. It is of immanent importance to use the limited resources of PT in an optimal and targeted manner in the ICU environment. The determination of ICU-adapted goals plays a crucial role.

Lung hyperinflation by mechanical ventilation versus isolated tracheal aspiration in the bronchial hygiene of patients undergoing mechanical ventilation

OBJECTIVE

To determine the efficacy of lung hyperinflation maneuvers via a mechanical ventilator compared to isolated tracheal aspiration for removing secretions, normalizing hemodynamics and improving lung mechanics in patients on mechanical ventilation.

METHODS

This was a randomized crossover clinical trial including patients admitted to the intensive care unit and on mechanical ventilation for more than 48 hours. Patients were randomized to receive either isolated tracheal aspiration (Control Group) or lung hyperinflation by mechanical ventilator (MVH Group). Hemodynamic and mechanical respiratory parameters were measured along with the amount of aspirated secretions.

RESULTS

A total of 50 patients were included. The mean age of the patients was 44.7 ± 21.6 years, and 31 were male. Compared to the Control Group, the MVH Group showed greater aspirated secretion amount (3.9g versus 6.4g, p = 0.0001), variation in mean dynamic compliance (-1.3 ± 2.3 versus -2.9 ± 2.3; p = 0.008), and expired tidal volume (-0.7 ± 0.0 versus -54.1 ± 38.8, p = 0.0001) as well as a significant decrease in peak inspiratory pressure (0.2 ± 0.1 versus 2.5 ± 0.1; p = 0.001).

CONCLUSION

In the studied sample, the MVH technique led to a greater amount of aspirated secretions, significant increases in dynamic compliance and expired tidal volume and a significant reduction in peak inspiratory pressure.