Outcomes and predictors of failure of non-invasive ventilation in patients with community acquired pneumonia in the ED

Objective

We set out to describe the use and analyze the predictors of non-invasive ventilation failure in patients with community-acquired pneumonia who receive non-invasive ventilation as first line ventilatory therapy in the emergency department.

Terbutaline lessens protein fluxes across the alveolo-capillary barrier during high-volume ventilation

Objective

To evaluate whether a β₂-adrenergic agonist may reduce acute alveolo-capillary barrier alterations during high-volume ventilation.

Design

Experimental study.

Setting

Animal research laboratory.

Subjects

A total of 48 male Wistar rats.

Interventions

A zone of alveolar flooding was produced by liquid instillation in a distal airway. Proteins in the instilled solution were traced with ^99mTc-albumin. ¹¹¹In, which binds to transferrin, was injected into the systemic circulation. Terbutaline was administered in the instilled solution or intra-peritoneally. Conventional ventilation was applied for 30?min followed by different ventilation strategies for 90?min: conventional ventilation, high-volume ventilation with or without 6?cmH₂O PEEP.

Measurements and main results

Protein fluxes across the alveolar and microvascular barriers were evaluated by scintigraphy. High-volume ventilation resulted in immediate leakage of ^99mTc-albumin from alveolar spaces and increased pulmonary uptake of systemic ¹¹¹In-transferrin. Terbutaline in the instilled solution and PEEP lessened alveolar ^99mTc-albumin leakage and pulmonary ¹¹¹In-transferrin uptake due to high-volume ventilation, whereas terbutaline given intra-peritoneally only lessened ¹¹¹In-transferrin uptake. Terbutaline in the instilled solution also lessened the increase in lung wet-to-dry weight ratio due to high-volume ventilation.

Conclusions

Terbutaline reduces protein fluxes across the alveolar epithelial and pulmonary microvascular barriers during high-volume ventilation in vivo. The route of administration may be important.

     

Explore the influence of BMI in the optimal time of weaning from sequential mechanical ventilation for severity chronic obstructive pulmonary disease

Objective

To study the clinical effect of body mass index (BMI) in the optimal time of weaning from sequential invasive-noninvasive mechanical ventilation (MV) by treating severity chronic obstructive pulmonary disease (COPD) patients.

Methods

94 patients with severity COPD were divided into the control group (BMI<21) and the study group (BMI>21). These two groups were treated by similar symptomatic therapies such as mechanical ventilation, antibacterial, antispasmodic, relieving asthma, antitussive, expectorant, correction of electrolyte imbalance and acid-base balance disorders, strengthen nutritional support, etc.

Results

Compared with the control group, the study group had shorter duration of invasive mechanical ventilation, non-invasive mechanical ventilation time, total mechanical ventilation time, total hospital stay (P<0.01). There are significant differences between these two groups in re-intubation rate, VAP occurred in the number of case, hospital mortality rate in 28 days (P<0.05).

Conclusions

It is difficult to wean successfully from sequential mechanical ventilation for severity COPD patients (BMI<21), so BMI as one of important reference index can be used to estimate the optimal time for weaning from sequential mechanical ventilation for severity COPD patients.

     

Variable ventilation improves ventilation and lung compliance in preterm lambs

Purpose  

In adult animals, ventilation with variable tidal volume and rate improves lung mechanics, arterial oxygenation and ventilation compared to a monotonously controlled ventilation pattern. We assessed the physiological consequences of variable ventilation in the immature lung.     

Determination of the appropriate oropharyngeal airway size in adults: Assessment using ventilation and an endoscopic view

Introduction

Size 9 and 8 airways for men and women, respectively, have been proposed as most appropriate based on endoscopy. However, a limitation of this guideline is that ventilation was not assessed.

Automatic protective ventilation using the ARDSNet protocol with the additional monitoring of electrical impedance tomography

Introduction

Automatic ventilation for patients with respiratory failure aims at reducing mortality and can minimize the workload of clinical staff, offer standardized continuous care, and ultimately save the overall cost of therapy. We therefore developed a prototype for closed-loop ventilation using acute respiratory distress syndrome network (ARDSNet) protocol, called autoARDSNet.

Methods

A protocol-driven ventilation using goal-oriented structural programming was implemented and used for 4 hours in seven pigs with lavage-induced acute respiratory distress syndrome (ARDS). Oxygenation, plateau pressure and pH goals were controlled during the automatic ventilation therapy using autoARDSNet. Monitoring included standard respiratory, arterial blood gas analysis and electrical impedance tomography (EIT) images. After 2-hour automatic ventilation, a disconnection of the animal from the ventilator was carried out for 10 seconds, simulating a frequent clinical scenario for routine clinical care or intra-hospital transport.

Results

This pilot study of seven pigs showed stable and robust response for oxygenation, plateau pressure and pH value using the automated system. A 10-second disconnection at the patient-ventilator interface caused impaired oxygenation and severe acidosis. However, the automated protocol-driven ventilation was able to solve these problems. Additionally, regional ventilation was monitored by EIT for the evaluation of ventilation in real-time at bedside with one prominent case of pneumothorax.

Conclusions

We implemented an automatic ventilation therapy using ARDSNet protocol with seven pigs. All positive outcomes were obtained by the closed-loop ventilation therapy, which can offer a continuous standard protocol-driven algorithm to ARDS subjects.     

Smaller self-inflating bags produce greater guideline consistent ventilation in simulated cardiopulmonary resuscitation

Background

Suboptimal bag ventilation in cardiopulmonary resuscitation (CPR) has demonstrated detrimental physiological outcomes for cardiac arrest patients. In light of recent guideline changes for resuscitation, there is a need to identify the efficacy of bag ventilation by prehospital care providers. The objective of this study was to evaluate bag ventilation in relation to operator ability to achieve guideline consistent ventilation rate, tidal volume and minute volume when using two different capacity self-inflating bags in an undergraduate paramedic cohort.

Methods

An experimental study using a mechanical lung model and a simulated adult cardiac arrest to assess the ventilation ability of third year Monash University undergraduate paramedic students. Participants were instructed to ventilate using 1600 ml and 1000 ml bags for a length of two minutes at the correct rate and tidal volume for a patient undergoing CPR with an advanced airway. Ventilation rate and tidal volume were recorded using an analogue scale with mean values calculated. Ethics approval was granted.

Results

Suboptimal ventilation with the use of conventional 1600 ml bag was common, with 77% and 97% of participants unable to achieve guideline consistent ventilation rates and tidal volumes respectively. Reduced levels of suboptimal ventilation arouse from the use of the smaller bag with a 27% reduction in suboptimal tidal volumes (p = 0.015) and 23% reduction in suboptimal minute volumes (p = 0.045).

Conclusion

Smaller self-inflating bags reduce the incidence of suboptimal tidal volumes and minute volumes and produce greater guideline consistent results for cardiac arrest patients.     

Chest compressions versus ventilation plus chest compressions: a randomized trial in a pediatric asphyxial cardiac arrest animal model

Purpose  

To compare survival, oxygenation, ventilation, and hemodynamic variables achieved with chest compressions or ventilation plus chest compressions.     

Education on invasive mechanical ventilation involving intensive care nurses: a systematic review

Background

Intensive care unit nurses are critical for managing mechanical ventilation. Continuing education is essential in building and maintaining nurses' knowledge and skills, potentially improving patient outcomes.

Aims

The aim of this study was to determine whether continuing education programmes on invasive mechanical ventilation involving intensive care unit nurses are effective in improving patient outcomes.

Methods

Five electronic databases were searched from 2001 to 2016 using keywords such as mechanical ventilation, nursing and education. Inclusion criteria were invasive mechanical ventilation continuing education programmes that involved nurses and measured patient outcomes. Primary outcomes were intensive care unit mortality and in‐hospital mortality. Secondary outcomes included hospital and intensive care unit length of stay, length of intubation, failed weaning trials, re‐intubation incidence, ventilation‐associated pneumonia rate and lung‐protective ventilator strategies. Studies were excluded if they excluded nurses, patients were ventilated for less than 24 h, the education content focused on protocol implementation or oral care exclusively or the outcomes were participant satisfaction. Quality was assessed by two reviewers using an education intervention critical appraisal worksheet and a risk of bias assessment tool. Data were extracted independently by two reviewers and analysed narratively due to heterogeneity.

Results

Twelve studies met the inclusion criteria for full review: 11 pre‐ and post‐intervention observational and 1 quasi‐experimental design. Studies reported statistically significant reductions in hospital length of stay, length of intubation, ventilator‐associated pneumonia rates, failed weaning trials and improvements in lung‐protective ventilation compliance. Non‐statistically significant results were reported for in‐hospital and intensive care unit mortality, re‐intubation and intensive care unit length of stay.

Conclusion

Limited evidence of the effectiveness of continuing education programmes on mechanical ventilation involving nurses in improving patient outcomes exists. Comprehensive continuing education is required.

Relevance to clinical practice

Well‐designed trials are required to confirm that comprehensive continuing education involving intensive care nurses about mechanical ventilation improves patient outcomes.

     

Systematic review of determinants of mortality in high frequency oscillatory ventilation in acute respiratory distress syndrome

Introduction  

Mechanical ventilation has been shown to cause lung injury and to have a significant impact on mortality in acute respiratory distress syndrome. Theoretically, high frequency oscillatory ventilation seems an ideal lung protective ventilation mode. This review evaluates determinants of mortality during use of high frequency oscillatory ventilation.     

Non-invasive mechanical ventilation for diagnostic bronchoscopy using a new face mask: an observational feasibility study

Purpose

Bronchoscopy is an indispensable tool for invasive pulmonary evaluation with high diagnostic yield and low incidence of major complications. However, hypoxemia increases the risk of complications, in particular after bronchoalveolar lavage. Non-invasive positive pressure ventilation may prevent hypoxemia associated with bronchoalveolar lavage. The purpose of this study is to present a modified total face mask to aid bronchoscopy during non-invasive positive pressure ventilation.

Methods

A commercially available full face mask was modified to allow introduction of the bronchoscope without interfering with the ventilator circuit. Bronchoscopy with bronchoalveolar lavage was performed in 12 hypoxemic non-ICU patients during non-invasive positive pressure ventilation in the ICU.

Results

Patients had severely impaired oxygen uptake as indicated by PaO₂/FiO₂ ratio 192  ± 23 mmHg before bronchoscopy. Oxygenation improved after initiation of non-invasive positive pressure ventilation. In all patients the procedure could be completed without subsequent complications, although in one patient SpO₂ decreased until 86% during bronchoscopy. A microbiological diagnosis could be established in 8 of 12 patients with suspected for infection.

Conclusions

Our modified face mask for non-invasive positive pressure ventilation is a valuable tool to aid diagnostic bronchoscopy in hypoxemic patients.     

Quantitative oral health assessments in mechanically ventilated patients: A scoping review

Background

Oral health is a key contributor to a person's overall health. Previous studies indicate that oral health deteriorates throughout ventilation and may contribute to the development of ventilator-associated pneumonia (VAP). Oral health at the time of initial ventilation may impact on this deterioration.

Aims

To determine the quantitative clinical assessment methods used to measure oral health and what is currently known regarding the oral health of patients at the time of initial ventilation.

Study Design

A systematic literature search using electronic bibliographic databases MEDLINE/PubMed, Embase, CINAHL, and the Cochrane Library was undertaken for this scoping review. Studies were included if patients were >18 years old and mechanically ventilated for <48 h at the time of the first oral assessment.

Results

In total, 12 studies were included. The review demonstrates a limited understanding of clinical oral health at the time of initial ventilation. Significant variation in both assessment methods and reporting of oral health makes comparison of results difficult resulting in a poor overall understanding of oral health at the time of intubation.

Conclusion

Standardized assessment and reporting methods may improve clinical application of findings and help direct future research. We suggest developing a core outcome set to ensure consistent use of assessment tools as well as standardized reporting of results.

Relevance to Clinical Practice

It is essential that a good understanding of oral health at the time of initial ventilation is gained so that patients receive more targeted oral hygiene intervention in ICU, potentially leading to improved patient outcomes.     

Distribution of lung ventilation in spontaneously breathing neonates lying in different body positions

Objective

The aim of our study was to determine the effect of the irregular spontaneous breathing pattern and posture on the spatial distribution of ventilation in neonates free from respiratory disease by the non-invasive imaging method of electrical impedance tomography (EIT). Scanning of spontaneously breathing neonates is the prerequisite for later routine application of EIT in babies with lung pathology undergoing ventilator therapy.

Design

Prospective study.

Setting

Neonatal intensive care unit at a university hospital.

Patients

Twelve pre-term and term neonates (mean age: 23 days; mean body weight: 2,465 g; mean gestational age: 34 weeks; mean birth weight: 2,040 g).

Interventions

Change in body position in the sequence: supine, right lateral, prone, supine.

Measurements and results

EIT measurements were performed using the Göttingen GoeMF I system. EIT scans of regional lung ventilation showing the distribution of respired air in the chest cross-section were generated during phases of rapid tidal breathing and deep breaths. During tidal breathing, 54.5±8.3%, 55.2±10.5%, 59.9±8.4% and 54.2±8.5% of inspired air (mean values ± SD) were directed into the right lung in the supine, right lateral, prone and repeated supine postures respectively. During deep inspirations, the right lung ventilation accounted for 52.6±7.9%, 68.5±8.5%, 55.4±8.2% and 50.5±6.6% of total ventilation respectively.

Conclusion

The study identified the significant effect of breathing pattern and posture on the spatial distribution of lung ventilation in spontaneously breathing neonates. The results demonstrate that changes in regional ventilation can easily be determined by EIT and bode well for the future use of this method in paediatric intensive care.

     

Adaptive support ventilation versus conventional ventilation for total ventilatory support in acute respiratory failure

Objective

To compare the short-term effects of adaptive support ventilation (ASV), an advanced closed-loop mode, with conventional volume or pressure-control ventilation in patients passively ventilated for acute respiratory failure.

Design

Prospective crossover interventional multicenter trial.

Setting

Six European academic intensive care units.

Patients

Eighty-eight patients in three groups: patients with no obvious lung disease (n = 22), restrictive lung disease (n = 36) or obstructive lung disease (n = 30).

Interventions

After measurements on conventional ventilation (CV) as set by the patients’ clinicians, each patient was switched to ASV set to obtain the same minute ventilation as during CV (isoMV condition). If this resulted in a change in PaCO₂, the minute ventilation setting of ASV was readjusted to achieve the same PaCO₂ as in CV (isoCO₂ condition).

Measurements and results

Compared with CV, PaCO₂ during ASV in isoMV condition and minute ventilation during ASV in isoCO₂ condition were slightly lower, with lower inspiratory work/minute performed by the ventilator (p < 0.01). Oxygenation and hemodynamics were unchanged. During ASV, respiratory rate was slightly lower and tidal volume (Vt) slightly greater (p < 0.01), especially in obstructed patients. During ASV there were different ventilatory patterns in the three groups, with lower Vt in patients with restrictive disease and prolonged expiratory time in obstructed patients, thus mimicking the clinicians’ choices for setting CV. In three chronic obstructive pulmonary disease patients the resulting Vt was unacceptably high.

Conclusions

Comparison between ASV and CV resulted either in similarities or in minor differences. Except for excessive Vt in a few obstructed patients, all differences were in favor of ASV.     

Head elevation and lateral head rotation effect on facemask ventilation efficiency: Randomized crossover trials

Purpose

We performed two prospective randomized crossover trials to evaluate the effect of head elevation or lateral head rotation to facemask ventilation volume.

Serine/threonine kinase-protein kinase B and extracellular signal-regulated kinase regulate ventilator-induced pulmonary fibrosis after bleomycin-induced acute lung injury: a prospective, controlled animal experiment

Introduction

Lung fibrosis, reduced lung compliance, and severe hypoxemia found in patients with acute lung injury often result in a need for the support of mechanical ventilation. High-tidal-volume mechanical ventilation can increase lung damage and fibrogeneic activity but the mechanisms regulating the interaction between high tidal volume and lung fibrosis are unclear. We hypothesized that high-tidal-volume ventilation increased pulmonary fibrosis in acute lung injury via the serine/threonine kinase-protein kinase B (Akt) and mitogen-activated protein kinase pathways.

Methods

After 5 days of bleomycin administration to simulate acute lung injury, male C57BL/6 mice, weighing 20 to 25 g, were exposed to either high-tidal-volume mechanical ventilation (30 ml/kg) or low-tidal-volume mechanical ventilation (6 ml/kg) with room air for 1 to 5 hours.

Results

High-tidal-volume ventilation induced type I and type III procollagen mRNA expression, microvascular permeability, hydroxyproline content, Masson's trichrome staining, S100A4/fibroblast specific protein-1 staining, activation of Akt and extracellular signal-regulated kinase (ERK) 1/2, and production of macrophage inflammatory protein-2 and 10 kDa IFNγ-inducible protein in a dose-dependent manner. High-tidal-volume ventilation-induced lung fibrosis was attenuated in Akt-deficient mice and in mice with pharmacologic inhibition of ERK1/2 activity by PD98059.

Conclusion

We conclude that high-tidal-volume ventilation-induced microvascular permeability, lung fibrosis, and chemokine production were dependent, in part, on activation of the Akt and ERK1/2 pathways.     

Mechanical ventilation and lung infection in the genesis of air-space enlargement

Introduction  

Air-space enlargement may result from mechanical ventilation and/or lung infection. The aim of this study was to assess how mechanical ventilation and lung infection influence the genesis of bronchiolar and alveolar distention.     

Head position angles to open the upper airway differ less with the head positioned on a support

Introduction

The aim of the study was to assess the effects of positioning the head on a support on “head position angles” to optimally open the upper airway during bag-valve mask ventilation.

Methods

We ventilated the lungs of anesthetized adults with a bag-valve mask and the head positioned with (n = 30) or without a support (n = 30). In both groups, head position angles and ventilation parameters were measured with the head positioned in (1) neutral position, (2) in a position deemed optimal for ventilation by the investigator, and (3) in maximal extension.

Results

Between groups (“head with/without a support”) and between head positions within each group, head position angles and ventilation parameters differed (P < .0001, respectively). However, head position angles and ventilation parameters between head positions differed less “with a support” (P < .001), and ventilation parameters improved with a support compared with the head-without-a-support group (P < .001).

Conclusions

In the head-with-a-support group, when compared with the head-without-a-support group, head position angles differed less, indicating a decreased potential for failure during bag-valve mask ventilation with the head on a support. Moreover, in the head-with-a-support group, ventilation parameters differed less between head positions, and ventilation improved. These findings suggest a potential benefit of positioning the head on a support during bag-valve mask ventilation.     

Pressure support ventilation attenuates ventilator-induced protein modifications in the diaphragm

Introduction  

Controlled mechanical ventilation (CMV) induces profound modifications of diaphragm protein metabolism, including muscle atrophy and severe ventilator-induced diaphragmatic dysfunction. Diaphragmatic modifications could be decreased by spontaneous breathing. We hypothesized that mechanical ventilation in pressure support ventilation (PSV), which preserves diaphragm muscle activity, would limit diaphragmatic protein catabolism.     

Recommendations for mechanical ventilation of critically ill children from the Paediatric Mechanical Ventilation Consensus Conference (PEMVECC)

Purpose

Much of the common practice in paediatric mechanical ventilation is based on personal experiences and what paediatric critical care practitioners have adopted from adult and neonatal experience. This presents a barrier to planning and interpretation of clinical trials on the use of specific and targeted interventions. We aim to establish a European consensus guideline on mechanical ventilation of critically children.

Methods

The European Society for Paediatric and Neonatal Intensive Care initiated a consensus conference of international European experts in paediatric mechanical ventilation to provide recommendations using the Research and Development/University of California, Los Angeles, appropriateness method. An electronic literature search in PubMed and EMBASE was performed using a combination of medical subject heading terms and text words related to mechanical ventilation and disease-specific terms.

Results

The Paediatric Mechanical Ventilation Consensus Conference (PEMVECC) consisted of a panel of 15 experts who developed and voted on 152 recommendations related to the following topics: (1) general recommendations, (2) monitoring, (3) targets of oxygenation and ventilation, (4) supportive measures, (5) weaning and extubation readiness, (6) normal lungs, (7) obstructive diseases, (8) restrictive diseases, (9) mixed diseases, (10) chronically ventilated patients, (11) cardiac patients and (12) lung hypoplasia syndromes. There were 142 (93.4%) recommendations with “strong agreement”. The final iteration of the recommendations had none with equipoise or disagreement.

Conclusions

These recommendations should help to harmonise the approach to paediatric mechanical ventilation and can be proposed as a standard-of-care applicable in daily clinical practice and clinical research.