Prognosis of mechanically ventilated patients with COVID-19 after failure of high-flow nasal cannula: a retrospective cohort study

BACKGROUND

There is an argument whether the delayed intubation aggravate the respiratory failure in Acute respiratory distress syndrome (ARDS) patients with coronavirus disease 2019 (COVID-19). We aimed to investigate the effect of high-flow nasal cannula (HFNC) failure before mechanical ventilation on clinical outcomes in mechanically ventilated patients with COVID-19.

METHODS

This retrospective cohort study included mechanically ventilated patients who were diagnosed with COVID-19 and admitted to the intensive care unit (ICU) between February 2020 and December 2021 at Asan Medical Center. The patients were divided into HFNC failure (HFNC-F) and mechanical ventilation (MV) groups according to the use of HFNC before MV. The primary outcome of this study was to compare the worst values of ventilator parameters from day 1 to day 3 after mechanical ventilation between the two groups.

RESULTS

Overall, 158 mechanically ventilated patients with COVID-19 were included in this study: 107 patients (67.7%) in the HFNC-F group and 51 (32.3%) in the MV group. The two groups had similar profiles of ventilator parameter from day 1 to day 3 after mechanical ventilation, except of dynamic compliance on day 3 (28.38 mL/cmH2O in MV vs. 30.67 mL/H2O in HFNC-F, p = 0.032). In addition, the HFNC-F group (5.6%) had a lower rate of ECMO at 28 days than the MV group (17.6%), even after adjustment (adjusted hazard ratio, 0.30; 95% confidence interval, 0.11-0.83; p = 0.045).

CONCLUSIONS

Among mechanically ventilated COVID-19 patients, HFNC failure before mechanical ventilation was not associated with deterioration of respiratory failure.

Enablers and barriers to adopt the locally developed Masi mechanical ventilator amid COVID-19 pandemic in Peru

Background

Limited supply of resources during the COVID-19 emergency encouraged the local development of the Masi mechanical ventilator (MV). Despite the efforts to promote Masi, adopting this innovation faced multiple obstacles, regardless of its performance. We explored the perceptions among healthcare personnel towards incorporating Masi to provide ventilatory support to COVID-19 patients during the second wave in Peru (January to June 2021).

Methods

We conducted twelve in-depth virtual interviews. Topics included experience when handling Masi, the impact of the training received, confidence in the device, barriers perceived, and enablers identified. All participants provided verbal informed consent.

Results

Most of the participants were male physicians. Participants belonged to seven hospitals that exhibited a wide range of healthcare capacities. Globally, the adoption of Masi MV was driven by the scarcity of ventilatory devices in the wards and reinforced by appropriate training and prompt technical support. Participants reported that Masi's structural and operational features played both advantages and disadvantages. Hospital infrastructure readiness, availability of commercial MVs, mistrust in its simple appearance, and resistance to change among healthcare personnel were perceived as barriers, while low-cost, prompt technical support and user-friendliness were valuable enablers. The first two enablers were observed in participants regardless of their attitude towards Masi. Despite the small number of participants for this qualitative study, it is important to note that the sample size was sufficient to reach saturation, as the topics discussed with participants became redundant and did not yield new information.

Conclusions

The perceptions among healthcare personnel to incorporate Masi as a mechanical ventilator for COVID-19 patients showed that communication, training and experience, and peer encouragement were essential to secure its use and sustainability of the technology. A priori judgments and perceptions unrelated to the performance of the novel device were observed, and its proper management may define its further implementation. Altogether our study suggests that along with strengthening local technological development, strategies to improve their adoption process must be considered as early as possible in medical innovations.

Mechanical hyperinflation maneuver and intracranial compliance of critical neurological patients: protocol for a randomized controlled equivalence trial

BACKGROUND

Mechanical hyperinflation maneuver (MHM) is a technique known for optimizing bronchial hygiene and respiratory mechanics; however, its effects on intracranial compliance are not known.

METHODS

Sixty patients aged ≥ 18 years, with clinical diagnosis of acute stroke, confirmed by neuroimaging examination, with onset of symptoms within 72 h, under mechanical ventilation through tracheal tube, will participate in this study. Participants will be randomly allocated into 2 groups: experimental group (n = 30)-MHM plus tracheal aspiration-and control group (n = 30)-tracheal aspiration only. Intracranial compliance will be measured by a non-invasive technique using Brain4care BcMM-R-2000 sensor. This will be the primary outcome. Results will be recorded at 5 times: T0 (start of monitoring), T1 (moment before MHM), T2 (moment after the MHM and before tracheal aspiration), T3 (moment after tracheal aspiration), T4, and T5 (monitoring 10 and 20 min after T3). Secondary outcomes are respiratory mechanics and hemodynamic parameters.

DISCUSSION

This study will be the first clinical trial to examine the effects and safety of MHM on intracranial compliance measured by non-invasive monitoring. Limitation includes the impossibility of blinding the physical therapist who will supervise the interventions. It is expected with this study to demonstrate that MHM can improve respiratory mechanics and hemodynamic parameters and provide a safe intervention with no changes in intracranial compliance in stroke patients.

Electric impedance tomography-guided PEEP titration reduces mechanical power in ARDS: a randomized crossover pilot trial

BACKGROUND

In patients with acute respiratory distress syndrome undergoing mechanical ventilation, positive end-expiratory pressure (PEEP) can lead to recruitment or overdistension. Current strategies utilized for PEEP titration do not permit the distinction. Electric impedance tomography (EIT) detects and quantifies the presence of both collapse and overdistension. We investigated whether using EIT-guided PEEP titration leads to decreased mechanical power compared to high-PEEP/FiO2 tables.

METHODS

A single-center, randomized crossover pilot trial comparing EIT-guided PEEP selection versus PEEP selection using the High-PEEP/FiO₂ table in patients with moderate-severe acute respiratory distress syndrome. The primary outcome was the change in mechanical power after each PEEP selection strategy. Secondary outcomes included changes in the 4 × driving pressure + respiratory rate (4 ΔP, + RR index) index, driving pressure, plateau pressure, PaO₂/FiO₂ ratio, and static compliance.

RESULTS

EIT was consistently associated with a decrease in mechanical power compared to PEEP/FiO₂ tables (mean difference - 4.36 J/min, 95% CI - 6.7, - 1.95, p = 0.002) and led to lower values in the 4ΔP + RR index (- 11.42 J/min, 95% CI - 19.01, - 3.82, p = 0.007) mainly driven by a decrease in the elastic-dynamic power (- 1.61 J/min, - 2.99, - 0.22, p = 0.027). The elastic-static and resistive powers were unchanged. Similarly, EIT led to a statistically significant change in set PEEP (- 2 cmH₂O, p = 0.046), driving pressure, (- 2.92 cmH2O, p = 0.003), peak pressure (- 6.25 cmH₂O, p = 0.003), plateau pressure (- 4.53 cmH₂O, p = 0.006), and static respiratory system compliance (+ 7.93 ml/cmH₂O, p = 0.008).

CONCLUSIONS

In patients with moderate-severe acute respiratory distress syndrome, EIT-guided PEEP titration reduces mechanical power mainly through a reduction in elastic-dynamic power. Trial registration This trial was prospectively registered on Clinicaltrials.gov (NCT03793842) on January 4th, 2019.

Disinfection efficacy of ozone on ESKAPE bacteria biofilms: Potential use in difficult-to-access medical devices

BACKGROUND

Medical devices can be reservoirs of multidrug-resistant bacteria that may be involved in the acquisition of infections since bacteria with the ability to form biofilms that are difficult to eradicate, mainly in mechanical ventilators. The aim of this work was to evaluate the efficacy of O₃ against biofilms of bacteria ESKAPE group through disinfection studies.

METHODS

The formation of biofilms of ESKAPE group bacteria was induced in vitro. O₃ was injected at different exposure times at a constant dose of 600 mg/h. The recovery of surviving bacteria after O₃ treatment was assessed by bacterial counts and biofilm disruption was analyzed. Finally, the viability and integrity of biofilms after O₃ treatment was determined by confocal laser scanning microscopy (CLSM).

RESULTS

O₃ showed bactericidal activity on biofilms from 12 min/7.68 ppm for A. baumannii and C. freundii. P. aeruginosa, K. pneumoniae and S. aureus were killed after 15 min/9.60 ppm. Correlation analyses showed inversely proportional relationships between the variables "disruption versus O₃". CLSM revealed that death was time-dependent of biofilms upon O₃ exposure. Orthogonal plane analysis showed that bacteria located in the outer region of the biofilms were the ones that initially suffered damage from O₃ exposure.

CONCLUSIONS

Our findings suggest that this method could be an alternative for the disinfection in mechanical ventilators colonized by bacteria biofilm forming.

Causes of adverse events in home mechanical ventilation: a nursing perspective

Background

Adverse events (AE) are ubiquitous in home mechanical ventilation (HMV) and can jeopardise patient safety. One particular source of error is human interaction with life-sustaining medical devices, such as the ventilator. The objective is to understand these errors and to be able to take appropriate action. With a systematic analysis of the hazards associated with HMV and their causes, measures can be taken to prevent damage to patient health.

Methods

A systematic adverse events analysis process was conducted to identify the causes of AE in intensive home care. The analysis process consisted of three steps. 1) An input phase consisting of an expert interview and a questionnaire. 2) Analysis and categorisation of the data into a root-cause diagram to help identify the causes of AE. 3) Derivation of risk mitigation measures to help avoid AE.

Results

The nursing staff reported that patient transportation, suction and tracheostomy decannulation were the main factors that cause AE. They would welcome support measures such as checklists for care activities and a reminder function, for e.g. tube changes. Risk mitigation measures are given for many of the causes listed in the root-cause diagram. These include measures such as device and care competence, as well as improvements to be made by the equipment providers and manufacturers. The first step in addressing AE is transparency and an open approach to errors and near misses. A systematic error analysis can prevent patient harm through a preventive approach.

Conclusion

Risks in HMV were identified based on a qualitative approach. The collected data was systematically mapped onto a root-cause diagram. Using the root-cause diagram, some of the causes were analysed for risk mitigation. For manufacturers, caregivers and care services requirements for intervention offers the possibility to create a checklist for particularly risky care activities.

Executive Summary: International Clinical Practice Guidelines for Pediatric Ventilator Liberation, A PALISI Network Document

RATIONALE

Pediatric specific ventilator liberation guidelines are lacking despite the many studies exploring elements of extubation readiness testing. The lack of clinical practice guidelines has led to significant and unnecessary variation in methods used to assess pediatric patients' readiness for extubation.

METHODS

Twenty-six international experts comprised a multi-professional panel to establish pediatric specific ventilator liberation clinical practice guidelines, focusing on acutely hospitalized children receiving invasive mechanical ventilation for more than 24 hours. Eleven key questions were identified and first prioritized using the Modified Convergence of Opinion on Recommendations and Evidence. Systematic review was conducted for questions which did not meet an a-priori threshold of ≥80% agreement, with Grading of Recommendations, Assessment, Development, and Evaluation methodologies applied to develop the guidelines. The panel evaluated the evidence, drafted, and voted on the recommendations.

MEASUREMENTS AND MAIN RESULTS

Three questions related to systematic screening, using an extubation readiness testing bundle and use of a spontaneous breathing trial as part of the bundle met Modified Convergence of Opinion on Recommendations criteria of ≥80% agreement. For the remaining 8 questions, 5 systematic reviews yielded 12 recommendations related to the methods and duration of spontaneous breathing trials; measures of respiratory muscle strength; assessment of risk of post-extubation upper airway obstruction and its prevention; use of post-extubation non-invasive respiratory support; and sedation. Most recommendations were conditional and based on low to very low certainty of evidence.

CONCLUSION

This clinical practice guideline provides a conceptual framework with evidence-based recommendations for best practices related to pediatric ventilator liberation. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Causes of use errors in ventilation devices - Systematic review

A systematic review according to the PRISMA reporting standard was performed to identify causes of use errors in mechanical ventilators described in the literature. The PubMed search resulted in the inclusion of 16 papers. The errors described were systematically analyzed with regard to their causes and categorized in an adapted cause-and-effect diagram. The causes of use errors were related to specific usability issues and to the general condition that medical staff often work with different ventilators. When many devices are used, the different user interfaces are a source of use errors, since, for example, the same ventilation modes have different names. In order to avoid the identified causes for use errors in the future, this work offers manufacturers of ventilation devices design recommendations and the possibility to include the results in their risk management. In addition, standardizing user interface content across all ventilators, as in ISO 19223, can help reduce use errors.

Efficacy of probiotics in the prevention of diarrhea in ventilated critically ill ICU patients: meta-analysis of randomized control trials

We comment on the study by Batra et al. on the efficacy of probiotics in the prevention of ventilator-associated pneumonia in critically ill ICU patients. They also reported that probiotics administration was not associated with a statistically significant reduction in the incidence of diarrhea (OR 0.59; CI 0.34, 1.03; P = 0.06; I ² = 38%). However, their meta-analysis missed one RCT, and when we repeated the analysis including this RCT, we found that probiotics administration significantly reduced the incidence of diarrhea (OR 0.51; CI 0.28, 0.92; P = 0.02; I ² = 45.6%). We thus believe that probiotics administration is effective in reducing the incidence of diarrhea in ventilated critically ill ICU patients.

Investigating the effect of materials and structures for negative pressure ventilators suitable for pandemic situation

The onset of the corona virus disease 2019 (COVID-19) pandemic caused shortages in mechanical ventilators (MVs) essential for the intensive care unit (ICU) in the hospitals. The increasing crisis prompted the investigation of ventilators which is low cost and offers lower health complications. Many researchers are revisiting the use of negative pressure ventilators (NPVs), due to the cost and complications of positive pressure ventilators (PPVs). This paper summarizes the evolution of the MVs, highlighting the limitations of popular positive and negative pressure ventilators and how NPV can be a cost-effective and lower health complication solution. This paper also provides a detailed investigation of the structure and material for the patient enclosure that can be used for a cost-effective NPV system using ANSYS simulations. The simulation results can confirm the selection and also help in developing a low cost while based on readily available materials. This can help the manufacturer to develop low-cost NPV and reduce the pressure on the healthcare system for any pandemic situation similar to COVID-19.

Clinical needs and technical requirements for ventilators for COVID-19 treatment critical patients: an evidence-based comparison for adult and pediatric age

The spread of severe acute respiratory syndrome coronavirus 2, taking on pandemic proportions, is placing extraordinary and unprecedented demands on healthcare systems worldwide. The increasing number of critical patients who, experiencing respiratory failure from acute respiratory distress syndrome, need respiratory support, has been leading countries to race against time in arranging new Intensive Care Units (ICUs) and in finding affordable and practical solutions to manage patients in each stage of the disease. The simultaneous worldwide emergency caused serious problems for mechanical ventilators supply. This chaotic scenario generated, indeed, a frenetic race to buy life-saving ventilators. However, the variety of mechanical ventilators designs, together with the limitations in time and resources, make the decision-making processes on ventilators procurement crucial and not counterbalanced by the evaluation of devices quality. This paper aimed at offering an overview of how evidence-based approach for health technologies evaluation, might provide support during Corona Virus Disease 2019 (COVID-19) pandemic in ICUs management and critical equipment supply. We compared and combined all the publicly available indications on the essential requirements that ICU ventilators might meet to be considered acceptable for treating COVID-19 patients in severe to critical illnesses. We hope that the critical analysis of these data might help readers to understand how structured decision-making processes based on evidence, evaluating the safety and effectiveness of a given medical device and the effects of its introduction in a healthcare setting, are able to optimize time and resources allocation that should be considered essential, especially during pandemic period.

Use and outcomes of mechanical ventilation for people with severe mental disorders admitted due to natural causes: A nationwide population-based study

OBJECTIVE

To characterize temporal trends and outcomes of invasive mechanical ventilation (MV) for people with severe mental disorders (SMD) admitted due to natural causes.

METHODS

We identified all 224,507 hospitalizations of patients aged 15-69 who underwent MV in Spain between 2000 and 2015, excluding poisonings and injuries, and divided them by presence of an SMD diagnosis. We compared the two study groups regarding demographic and clinical characteristics and examined time trends in the incidence of MV and in-hospital mortality.

RESULTS

SMD patients were younger and had fewer comorbidities and lower in-hospital mortality than the non-SMD group. However, among patients admitted due to circulatory diseases, SMD patients had higher mortality risk (OR = 1.39; 95%CI = 1.22-1.59). In the SMD group, the increase in MV use quadrupled that of non-SMD patients (Average Annual Percent Change = 6.9%; 95%CI = 5.5-8.3 vs. 1.5%; 0.9-2.0, respectively). Overall in-hospital mortality declined similarly in both study groups. While the SMD group's circulatory-specific mortality also decreased, by 2015 it remained elevated in comparison to non-SMD patients (44% vs. 38%, respectively).

CONCLUSION

The increase in MV use due to natural causes among people with SMD outpaced that of non-SMD patients, with comparable decreasing trends in mortality. Although declining, SMD patients' higher circulatory-specific mortality risk requires further investigation.

Predictors of asynchronies during assisted ventilation and its impact on clinical outcomes: The EPISYNC cohort study

PURPOSE

To investigate if respiratory mechanics and other baseline characteristics are predictors of patient-ventilator asynchrony and to evaluate the relationship between asynchrony during assisted ventilation and clinical outcomes.

METHODS

We performed a prospective cohort study in patients under mechanical ventilation (MV). Baseline measurements included severity of illness and respiratory mechanics. The primary outcome was the Asynchrony Index (AI), defined as the number of asynchronous events divided by the number of ventilator cycles and wasted efforts. We recorded ventilator waveforms throughout the entire period of MV.

RESULTS

We analyzed 11,881 h of MV from 103 subjects. Median AI during the entire period of MV was 5.1% (IQR:2.6-8.7). Intrinsic PEEP was associated with AI (OR:1.72, 95%CI:1.1-2.68), but static compliance and airway resistance were not. Simplified Acute Physiology Score 3 (OR:1.03, 95%CI:1-1.06) was also associated with AI. Median AI was higher during assisted (5.4%, IQR:2.9-9.1) than controlled (2%, IQR:0.6-4.9) ventilation, and 22% of subjects had high incidence of asynchrony (AI≥10%). Subjects with AI≥10% had more extubation failure (33%) than patients with AI<10% (6%), p = .01.

CONCLUSIONS

Predictors of high incidence of asynchrony were severity of illness and intrinsic PEEP. High incidence of asynchrony was associated with extubation failure, but not mortality.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02687802.

An Early Tailored Approach Is the Key to Effective Rehabilitation in the Intensive Care Unit

OBJECTIVE

To investigate the effectiveness, feasibility, and safety of an evidence-based rehabilitation care pathway in the intensive care unit (ICU) in different patient populations.

DESIGN

Observational prospective cohort study, with retrospective controls.

SETTING

ICUs of a university hospital.

PARTICIPANTS

Patients admitted between April 1, 2015, and June 30, 2015, were compared to a retrospective cohort admitted to the same ICUs during the same 3-month period in 2014. The number of patients studied (N=285) included 152 in the prospective group and 133 in the retrospective group.

INTERVENTIONS

The prospective cohort benefited of a rehabilitation care pathway based on (1) interdisciplinary teamwork; (2) early customized and goal-oriented rehabilitation; (3) daily functional monitoring and treatment revision; (4) agreed discharge policy; and (5) continuity of care. The retrospective cohort underwent usual care.

MAIN OUTCOME MEASURES

Included the following: (1) proportions of patients undergoing rehabilitation team evaluation; (2) latency between patient admission to ICUs and rehabilitation team assessment; (3) proportions of patients undergoing rehabilitation treatment during ICU stay; (4) latency between the patient admission to ICUs and rehabilitation start; (5) ICU stay and total acute hospital stay; and (5) proportion of ventilator-free days out of ICU stay.

RESULTS

The novel rehabilitation care pathway led to (1) an increased proportion of patients receiving rehabilitative assessment (P<.0001); (2) a decreased latency from ICU admission to both rehabilitation team assessment and rehabilitation start (P<.0001); (3) an increased proportion of patients undergoing rehabilitation (P<.0001); (4) a shorter length of stay in ICUs (P<.0001) and in hospital (P=.047); and (5) a shorter mechanical ventilation duration (P<.02). A direct relationship between rehabilitation start latency and ICU length of stay was observed.

CONCLUSIONS

An early, interdisciplinary team approach, providing a customized dynamic planning of physiotherapy programs, increases ventilator-free time and reduces total hospital stay, especially in patients admitted to the ICU after general surgery. This rehabilitation care pathway can be generalized to different geopolitical scenarios, being feasible, safe and cost effective.

Simulation of pressure support for spontaneous breathing trials in neonates

BACKGROUND

Endotracheal tubes used for neonates are not as resistant to breathing as originally anticipated; therefore, spontaneous breathing trials (SBTs) with continuous positive airway pressure (CPAP), without pressure support (PS), are recommended. However, PS extubation criteria have predetermined pressure values for each endotracheal tube diameter (PS 10 cmH₂O with 3.0- and 3.5-mm tubes or PS 8 cmH₂O with 4.0-mm tubes). This study aimed to assess the validity of these SBT criteria for neonates, using an artificial lung simulator, ASL 5000™ lung simulator, and a SERVO-i Universal™ ventilator (minute volume, 240-360 mL/kg/min; tidal volume, 30 mL; respiratory rate, 24-36/min; lung compliance, 0.5 mL/cmH₂O/kg; resistance, 40 cmH₂O/L/s) in an intensive care unit. We simulated a spontaneous breathing test in a 3-kg neonate after cardiac surgery with 3.0-3.5-mm endotracheal tubes. We measured the work of breathing (WOB), trigger work, and parameters of pressure support ventilation (PSV), T-piece breathing, or ASL 5000™ alone.

RESULTS

WOB displayed respiratory rate dependency under intubation. PS compensating tube resistance fluctuated with respiratory rate. At a respiratory rate of 24/min, the endotracheal tube did not greatly influence WOB under PSV and the regression line of WOB converged with the WOB of ASL 5000™ alone under PS 1 cmH₂O; however, at 36/min, endotracheal tube was resistant to breathing under PSV because trigger work increased exponentially with PS ≤ 9 cmH₂O. The regression line of WOB under PSV converged with the WOB of T-piece breathing under PS 1 cmH₂O. Furthermore, PS compensating endotracheal tube resistance was 6 cmH₂O. The WOB of ASL 5000™ alone approached that of respiratory distress syndrome (RDS); however, the pressure of patient effort was normal physiological range at PS 10 cmH₂O. PS equalizing WOB under PSV with that after extubation depended on the respiratory rate and upper airway resistance. If WOB after extubation equaled that of T-piece breathing, the PS was 0 cmH₂O regardless of the respiratory rates. If WOB after extubation approximated  to that of ASL 5000™ alone, the PS depended on the respiratory rate.

CONCLUSION

SBT strategies should be selected per neonatal respiratory rates and upper airway resistance.

Early mobilisation in mechanically ventilated patients: a systematic integrative review of definitions and activities

Background

Mechanically ventilated patients often develop muscle weakness post-intensive care admission. Current evidence suggests that early mobilisation of these patients can be an effective intervention in improving their outcomes. However, what constitutes early mobilisation in mechanically ventilated patients (EM-MV) remains unclear. We aimed to systematically explore the definitions and activity types of EM-MV in the literature.

Methods

Whittemore and Knafl’s framework guided this review. CINAHL, MEDLINE, EMBASE, PsycINFO, ASSIA, and Cochrane Library were searched to capture studies from 2000 to 2018, combined with hand search of grey literature and reference lists of included studies. The Critical Appraisal Skills Programme tools were used to assess the methodological quality of included studies. Data extraction and quality assessment of studies were performed independently by each reviewer before coming together in sub-groups for discussion and agreement. An inductive and data-driven thematic analysis was undertaken on verbatim extracts of EM-MV definitions and activities in included studies.

Results

Seventy-six studies were included from which four major themes were inferred: (1) non-standardised definition, (2) contextual factors, (3) negotiated process and (4) collaboration between patients and staff. The first theme indicates that EM-MV is either not fully defined in studies or when a definition is provided this is not standardised across studies. The remaining themes reflect the diversity of EM-MV activities which depends on patients’ characteristics and ICU settings; the negotiated decision-making process between patients and staff; and their interdependent relationship during the implementation.

Conclusions

This review highlights the absence of an agreed definition and on what constitutes early mobilisation in mechanically ventilated patients. To advance research and practice an agreed and shared definition is a pre-requisite.

Modes of mechanical ventilation vary between hospitals and intensive care units within a university healthcare system: a retrospective observational study

Objective

As evidence-based guidance to aid clinicians with mechanical ventilation mode selection is scant, we sought to characterize the epidemiology thereof within a university healthcare system and hypothesized that nonconforming approaches could be readily identified. We conducted an exploratory retrospective observational database study of routinely recorded mechanical ventilation parameters between January 1, 2010 and December 31, 2016 from 12 intensive care units. Mode epoch count proportions were examined using Chi squared and Fisher exact tests as appropriate on an inter-unit basis with outlier detection for two test cases via post hoc pairwise analyses of a binomial regression model.

Results

Final analysis included 559,734 mode epoch values. Significant heterogeneity was demonstrated between individual units (P < 0.05 for all comparisons). One unit demonstrated heightened utilization of high-frequency oscillatory ventilation, and three units demonstrated frequent synchronized intermittent mandatory ventilation utilization. Assist control ventilation was the most commonly recorded mode (51%), followed by adaptive support ventilation (23.1%). Volume-controlled modes were about twice as common as pressure-controlled modes (64.4% versus 35.6%). Our methodology provides a means by which to characterize the epidemiology of mechanical ventilation approaches and identify nonconforming practices. The observed variability warrants further clinical study about contributors and the impact on relevant outcomes.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3534-z) contains supplementary material, which is available to authorized users.

Cardiac function associated with home ventilator care in Duchenne muscular dystrophy

Purpose

Cardiomyopathy is becoming the leading cause of death in patients with Duchenne muscular dystrophy because mechanically assisted lung ventilation and assisted coughing have helped resolve respiratory complications. To clarify cardiopulmonary function, we compared cardiac function between the home ventilator-assisted and non-ventilator-assisted groups.

Methods

We retrospectively reviewed patients with Duchenne muscular dystrophy from January 2010 to March 2016 at Gangnam Severance Hospital. Demographic characteristics, pulmonary function, and echocardiography data were investigated.

Results

Fifty-four patients with Duchenne muscular dystrophy were divided into 2 groups: home ventilator-assisted and non-ventilator-assisted. The patients in the home ventilator group were older (16.25±1.85 years) than those in the nonventilator group (14.73±1.36 years) (P=0.001). Height, weight, and body surface area did not differ significantly between groups. The home ventilator group had a lower seated functional vital capacity (1,038±620.41 mL) than the nonventilator group (1,455±603.12 mL). Mean left ventricular ejection fraction and fractional shortening were greater in the home ventilator group, but the data did not show any statistical difference. The early ventricular filling velocity/late ventricular filling velocity ratio (1.7±0.44) was lower in the home ventilator group than in the nonventilator group (2.02±0.62). The mitral valve annular systolic velocity was higher in the home ventilator group (estimated β, 1.06; standard error, 0.48). Patients with Duchenne muscular dystrophy on a ventilator may have better systolic and diastolic cardiac functions.

Conclusion

Noninvasive ventilator assistance can help preserve cardiac function. Therefore, early utilization of noninvasive ventilation or oxygen may positively influence cardiac function in patients with Duchenne muscular dystrophy.

Difference in inspiratory flow between volume and pressure control ventilation in patients with flow dyssynchrony

PURPOSE

Flow dyssynchrony is common during volume control ventilation but minimized during pressure control. Characterizing inspiratory flow during pressure control breaths can inform adjustments of the fixed flow of volume control to address flow dyssynchrony. This study compared inspiratory flow peak and pattern between volume control and adaptive pressure control breaths.

MATERIAL AND METHODS

Subjects with or at risk for ARDS were ventilated with volume control decreasing ramp flow at different tidal volumes and subsequently with adaptive pressure control targeting those same tidal volumes. Inspiratory flows of volume control breaths exhibiting flow dyssynchrony, and those of pressure control breaths at the same set tidal volumes without flow dyssynchrony were analyzed, for a total of 17 subject-tidal volume conditions. Peak flow and flows at 10, 25, 50 and 75% of inspiratory time were compared between modes.

RESULTS

Group peak flows were not different between modes, but at 50 and 75% of inspiratory time flows were higher during adaptive pressure control. In 8 subject-tidal volume conditions V_T were higher (>1ml/kg PBW) on adaptive pressure control than on volume control.

CONCLUSIONS

In patients with flow dyssynchrony during volume control ventilation, adjustment of inspiratory flow pattern should be considered to minimize this dyssynchrony.

Effects of intrapulmonary percussive ventilation on airway mucus clearance: A bench model

AIM

To determine the ability of intrapulmonary percussive ventilation (IPV) to promote airway clearance in spontaneously breathing patients and those on mechanical ventilation.

METHODS

An artificial lung was used to simulate a spontaneously breathing patient (Group 1), and was then connected to a mechanical ventilator to simulate a patient on mechanical ventilation (Group 2). An 8.5 mm endotracheal tube (ETT) connected to the test lung, simulated the patient airway. Artificial mucus was instilled into the mid-portion of the ETT. A filter was attached at both ends of the ETT to collect the mucus displaced proximally (mouth-piece filter) and distally (lung filter). The IPV machine was attached to the proximal end of the ETT and was applied for 10-min each to Group 1 and 2. After each experiment, the weight of the various circuit components were determined and compared to their dry weights to calculate the weight of the displaced mucus.

RESULTS

In Group 1 (spontaneously breathing model), 26.8% ± 3.1% of the simulated mucus was displaced proximally, compared to 0% in Group 2 (the mechanically ventilated model) with a P-value of < 0.01. In fact, 17% ± 1.5% of the mucus in Group 2 remained in the mid-portion of the ETT where it was initially instilled and 80% ± 4.2% was displaced distally back towards the lung (P < 0.01). There was an overall statistically significant amount of mucus movement proximally towards the mouth-piece in the spontaneously breathing (SB) patient. There was also an overall statistically significant amount of mucus movement distally back towards the lung in the mechanically ventilated (MV) model. In the mechanically ventilated model, no mucus was observed to move towards the proximal/mouth piece section of the ETT.

CONCLUSION

This bench model suggests that IPV is associated with displacement of mucus towards the proximal mouthpiece in the SB patient, and distally in the MV model.

Predicted body weight relationships for protective ventilation - unisex proposals from pre-term through to adult

BACKGROUND

The lung-protective ventilation bundle has been shown to reduce mortality in adult acute respiratory distress syndrome (ARDS). This concept has expanded to other areas of acute adult ventilation and is recommended for pediatric ventilation. A component of lung-protective ventilation relies on a prediction of lean body weight from height. The predicted body weight (PBW) relationship employed in the ARDS Network trial is considered valid only for adults, with a dedicated formula required for each sex. No agreed PBW formula applies to smaller body sizes. This analysis investigated whether it might be practical to derive a unisex PBW formula spanning all body sizes, while retaining relevance to established adult protective ventilation practice.

METHODS

Historic population-based growth charts were adopted as a reference for lean body weight, from pre-term infant through to adult median weight. The traditional ARDSNet PBW formulae acted as the reference for prevailing protective ventilation practice. Error limits for derived PBW models were relative to these references.

RESULTS

The ARDSNet PBW formulae typically predict weights heavier than the population median, therefore no single relationship could satisfy both references. Four alternate piecewise-linear lean body-weight predictive formulae were presented for consideration, each with different balance between the objectives.

CONCLUSIONS

The 'PBWuf + MBW' model is proposed as an appropriate compromise between prevailing practice and simplification, while also better representing lean adult body-weight. This model applies the ARDSNet 'female' formula to both adult sexes, while providing a tight fit to median body weight at smaller statures down to pre-term. The 'PBWmf + MBW' model retains consistency with current practice over the adult range, while adding prediction for small statures.

[Threshold value of f/Vt index for predicting successful weaning from mechanical ventilation in active smokers]

BACKGROUND

Mechanical ventilation (MV) is used in 60-70 % of patients admitted to the intensive care unit (ICU). An f/Vt threshold value of 105 is a predictor of successful weaning from mechanical ventilation (WMV) in patients with asthma, cardiac surgery, pneumonia, sepsis, neurocritical, etc. However, there are no reports about the usefulness of the f/Vt value to predict successful WMV in patients with active smoking (AS). The purpose of this paper is to identify a threshold value for f/Vt to predict successful WMV in patients with AS.

METHODS

Prospectively, 85 patients with AS and MV >24 hours admitted to de ICU were included. Demographic and clinical data were registered. The f/Vt value was measured with a Wright's spirometer, and the sensibility, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated to predict a successful WMV. A p value <0.05 was considered statistically significant.

RESULTS

The average of f/Vt was 68.69. Successful WMV was of 75.3 %. An f/Vt threshold value of 79.5 had sensibility of 76 %, specificity of 61 %, PPV of 85 %, and NPV of 46 % to predict successful WMV in this group of patients.

CONCLUSIONS

An f/Vt threshold value of 79.5 is useful to predict successful WMV in patients with AS.

Inspiratory muscle training is used in some intensive care units, but many training methods have uncertain efficacy: a survey of French physiotherapists

QUESTIONS

How common is inspiratory muscle training by physiotherapists in the intensive care unit (ICU)? Which patients receive the training? What methods are used to administer the training? Is maximal inspiratory pressure used to evaluate the need for the training and the patient's outcome after training?

DESIGN

Cross-sectional survey of all ICUs in France.

PARTICIPANTS

Two hundred and sixty-five senior physiotherapists.

RESULTS

The response rate was 99% among eligible units. Therapist experience in ICU was significantly associated with the use of inspiratory muscle training (p=0.02). Therapists mainly used inspiratory muscle training either systematically or specifically in patients who failed to wean from mechanical ventilation. The training was used significantly more in non-sedated patients (p<0.0001). The most commonly nominated technique that respondents claimed to use to apply the training was controlled diaphragmatic breathing (83% of respondents), whereas 13% used evidence-based methods. Among those who applied some form of inspiratory muscle training, 16% assessed maximal inspiratory pressure. Six respondents (2%, 95% CI 1 to 5) used both an evidence-based method to administer inspiratory muscle training and the recommended technique for assessment of inspiratory muscle strength.

CONCLUSION

Most physiotherapists in French ICUs who apply inspiratory muscle training use methods of uncertain efficacy without assessment of maximal inspiratory pressure. Further efforts need to be made in France to disseminate information regarding evidence-based assessment and techniques for inspiratory muscle training in the ICU. The alignment of inspiratory muscle training practice with evidence could be investigated in other regions.

Inspiratory muscle training facilitates weaning from mechanical ventilation among patients in the intensive care unit: a systematic review

QUESTION

Does inspiratory muscle training improve inspiratory muscle strength in adults receiving mechanical ventilation? Does it improve the duration or success of weaning? Does it affect length of stay, reintubation, tracheostomy, survival, or the need for post-extubation non-invasive ventilation? Is it tolerable and does it cause adverse events?

DESIGN

Systematic review of randomised trials.

PARTICIPANTS

Adults receiving mechanical ventilation.

INTERVENTION

Inspiratory muscle training versus sham or no inspiratory muscle training.

OUTCOME MEASURES

Data were extracted regarding: inspiratory muscle strength and endurance; the rapid shallow breathing index; weaning success and duration; duration of mechanical ventilation; reintubation; tracheostomy; length of stay; use of non-invasive ventilation after extubation; survival; readmission; tolerability and adverse events.

RESULTS

Ten studies involving 394 participants were included. Heterogeneity within some meta-analyses was high. Random-effects meta-analyses showed that the training significantly improved maximal inspiratory pressure (MD 7 cmH2O, 95% CI 5 to 9), the rapid shallow breathing index (MD 15 breaths/min/l, 95% CI 8 to 23) and weaning success (RR 1.34, 95% CI 1.02 to 1.76). Although only assessed in individual studies, significant benefits were also reported for the time spent on non-invasive ventilation after weaning (MD 16 hours, 95% CI 13 to 18), length of stay in the intensive care unit (MD 4.5 days, 95% CI 3.6 to 5.4) and length of stay in hospital (MD 4.4 days, 95% CI 3.4 to 5.5). Weaning duration decreased in the subgroup of patients with known weaning difficulty. The other outcomes weren't significantly affected or weren't measured.

CONCLUSION

Inspiratory muscle training for selected patients in the intensive care unit facilitates weaning, with potential reductions in length of stay and the duration of non-invasive ventilatory support after extubation. The heterogeneity among the results suggests that the effects of inspiratory muscle training may vary; this perhaps depends on factors such as the components of usual care or the patient's characteristics.

Low-tidal volume mechanical ventilation in patients with acute respiratory distress syndrome caused by pandemic influenza A/H1N1 infection

PURPOSE

Low-tidal volume (TV) mechanical ventilation is an important manipulation in managing patients with acute respiratory distress syndrome (ARDS). However, there is no definite evidence to support the use of this intervention in patients with viral etiologies.

MATERIALS AND METHODS

A retrospective observational study of 104 patients with ARDS caused by pandemic influenza A/H1N1 infection admitted to 28 intensive care units (ICUs) in Korea was performed. Patients were categorized into 3 groups according to the TV they received: TV less than or equal to 7 mL/kg, TV greater than 7 mL/kg but less than or equal to 9 mL/kg, or TV greater than 9 mL/kg.

RESULTS

The mean age was 55.1 years, and 55.8% were male (n = 58). Patients with TV greater than 9 mL/kg showed higher 28-day ICU mortality than the 2 other groups (vs TV < 7 mL/kg, P = .007 and vs 7 mL/kg < TV ≤ 9 mL/kg, P = .004, respectively). Patients with TV less than or equal to 7 mL/kg required ventilators, ICU admissions, and hospitalizations for fewer days than those with TV greater than 7 mL/kg (11.4 vs 6.1 days for 28-day ventilator-free days, 9.7 vs 4.9 days for 28-day ICU-free days, and 5.2 vs 2.4 days for 28-day hospital-free days, respectively). Tidal volume greater than 9 mL/kg (hazard rate, 2.459; P = .003) and Sequential Organ Failure Assessment score (hazard rate, 1.158; P = .014) were significant predictors of 28-day ICU mortality.

CONCLUSIONS

Low-TV mechanical ventilation still benefits patients with ARDS caused by viral pneumonia.