A randomized controlled trial comparing the ventilation duration between adaptive support ventilation and pressure assist/control ventilation in medical patients in the ICU

Evaluation of decision support to wean patients from mechanical ventilation in intensive care: a prospective study reporting clinical and physiological outcomes

This study investigated the clinical and physiological response to use of the BEACON Caresystem, a bedside open-loop decision support system providing advice to guide clinicians when weaning patients from invasive mechanical ventilation. Multicenter prospective study conducted in five adult intensive care units in the UK. Following screening and assent, intubated patients mechanically ventilated for > 24 h were randomized to intervention or usual care. Intervention consisted of application of the BEACON Caresystem's advice on tidal volume/inspiratory pressure, inspired oxygen, respiratory rate and PEEP. Usual care was defined as local clinical practice. The primary outcome was duration of mechanical ventilation. Secondary outcomes quantified prolonged intubation and survival; adverse events; ventilator settings and physiological state; time spent in ventilator modes; links to other therapy; the frequency of advice utilization and time spent outside normal physiological limits. The study was terminated early with a total of 112 patients included. Fifty-four were randomised to the intervention arm and fifty-eight to usual care. The study was underpowered and no significant differences were seen in duration of mechanical ventilation (p = 0.773), prolonged intubation or survival. Intervention arm patients had lower rates of adverse events (p = 0.016), including fewer hypoxaemic events (p = 0.008) and lower values of PEEP (p = 0.030) and tidal volume (p = 0.042). Values of peak inspiratory pressure and pressure support were reduced but at the boarder of statistical significance (p = 0.104, p = 0.093, respectively). No differences were seen for time in ventilator mode or other therapy. Advice presented by the decision support system was applied at the beside an average of 88% of occasions, with a significantly increased number of changes only in inspired oxygen fraction. No significant differences were seen in time spent outside physiological limits. This study investigated the use of the BEACON Caresystem, an open loop clinical decision support system providing advice on ventilator settings. It was terminated early, with no significant difference shown in duration of mechanical ventilation, the primary outcome. Application of advice indicated potential for fewer adverse events and improved physiological status. (Trial registration ClinicalTrials.gov under NCT03249623. Registered 22nd June 2017).

A randomized control trial evaluating the advice of a physiological-model/digital twin-based decision support system on mechanical ventilation in patients with acute respiratory distress syndrome

Background

Acute respiratory distress syndrome (ARDS) is highly heterogeneous, both in its clinical presentation and in the patient's physiological responses to changes in mechanical ventilator settings, such as PEEP. This study investigates the clinical efficacy of a physiological model-based ventilatory decision support system (DSS) to personalize ventilator therapy in ARDS patients.

Methods

This international, multicenter, randomized, open-label study enrolled patients with ARDS during the COVID-19 pandemic. Patients were randomized to either receive active advice from the DSS (intervention) or standard care without DSS advice (control). The primary outcome was to detect a reduction in average driving pressure between groups. Secondary outcomes included several clinically relevant measures of respiratory physiology, ventilator-free days, time from control mode to support mode, number of changes in ventilator settings per day, percentage of time in control and support mode ventilation, ventilation- and device-related adverse events, and the number of times the advice was followed.

Results

A total of 95 patients were randomized in this study. The DSS showed no significant effect on average driving pressure between groups. However, patients in the intervention arm had a statistically improved oxygenation index when in support mode ventilation (-1.41, 95% CI: -2.76, -0.08; p = 0.0370). Additionally, the ventilatory ratio significantly improved in the intervention arm for patients in control mode ventilation (-0.63, 95% CI: -1.08, -0.17, p = 0.0068). The application of the DSS led to a significantly increased number of ventilator changes for pressure settings and respiratory frequency.

Conclusion

The use of a physiological model-based decision support system for providing advice on mechanical ventilation in patients with COVID-19 and non-COVID-19 ARDS showed no significant difference in driving pressure as a primary outcome measure. However, the application of approximately 60% of the DSS advice led to improvements in the patient's physiological state.

Clinical trial registration

clinicaltrials.gov, NCT04115709.

Effects of closed loop ventilation on ventilator settings, patient outcomes and ICU staff workloads - a systematic review

BACKGROUND

Lung protective ventilation is considered standard of care in the intensive care unit. However, modifying the ventilator settings can be challenging and is time consuming. Closed loop modes of ventilation are increasingly attractive for use in critically ill patients. With closed loop ventilation, settings that are typically managed by the ICU professionals are under control of the ventilator's algorithms.

OBJECTIVES

To describe the effectiveness, safety, efficacy and workload with currently available closed loop ventilation modes.

DESIGN

Systematic review of randomised clinical trials.

DATA SOURCES

A comprehensive systematic search in PubMed, Embase and the Cochrane Central register of Controlled Trials search was performed in January 2023.

ELIGIBILITY CRITERIA

Randomised clinical trials that compared closed loop ventilation with conventional ventilation modes and reported on effectiveness, safety, efficacy or workload.

RESULTS

The search identified 51 studies that met the inclusion criteria. Closed loop ventilation, when compared with conventional ventilation, demonstrates enhanced management of crucial ventilator variables and parameters essential for lung protection across diverse patient cohorts. Adverse events were seldom reported. Several studies indicate potential improvements in patient outcomes with closed loop ventilation; however, it is worth noting that these studies might have been underpowered to conclusively demonstrate such benefits. Closed loop ventilation resulted in a reduction of various aspects associated with the workload of ICU professionals but there have been no studies that studied workload in sufficient detail.

CONCLUSIONS

Closed loop ventilation modes are at least as effective in choosing correct ventilator settings as ventilation performed by ICU professionals and have the potential to reduce the workload related to ventilation. Nevertheless, there is a lack of sufficient research to comprehensively assess the overall impact of these modes on patient outcomes, and on the workload of ICU staff.

Management of Chronic Obstructive Pulmonary Disease (COPD) Exacerbations in Hospitalized Patients From Admission to Discharge: A Comprehensive Review of Therapeutic Interventions

Chronic obstructive pulmonary disease (COPD) is a common and debilitating condition that often necessitates hospitalization for exacerbations. Since COPD exacerbations can cause significant morbidity and mortality, managing them is crucial for patient care. Effective management of COPD exacerbations is essential to prevent complications, as COPD exacerbations are associated with increased healthcare costs and decreased quality of life. This review aims to comprehensively discuss the management of COPD exacerbations, covering various pharmacologic and non-pharmacologic strategies. These include inhaled bronchodilators, systemic steroids, antibiotics, invasive and non-invasive ventilation, oxygen therapy, smoking cessation, immunization with pneumococcal vaccine, inhalers at discharge, pulmonary rehabilitation, long-term oxygen therapy (LTOT), ambulatory oxygen therapy, short-burst oxygen therapy, extracorporeal membrane oxygenation (ECMO), lung volume reduction surgery (LVRS), endobronchial procedures, and lung transplant. It is drawn upon various sources, including clinical studies, systemic reviews, and observational studies, to provide a comprehensive overview of current practices and identify areas for future research and innovation in managing COPD exacerbations. Addressing these areas of interest can improve patient outcomes and quality of life.

Heterogeneity of surrogate outcome measures used in critical care studies: A systematic review

BACKGROUND

The choice of outcome measure is a critical decision in the design of any clinical trial, but many Phase III clinical trials in critical care fail to detect a difference between the interventions being compared. This may be because the surrogate outcomes used to show beneficial effects in early phase trials (which informed the design of the subsequent Phase III trials) are not valid guides to the differences between the interventions for the main outcomes of the Phase III trials. We undertook a systematic review (1) to generate a list of outcome measures used in critical care trials, (2) to determine the variability in the outcome reporting in the respiratory subgroup and (3) to create a smaller list of potential early phase endpoints in the respiratory subgroup.

METHODS

Data related to outcomes were extracted from studies published in the six top-ranked critical care journals between 2010 and 2020. Outcomes were classified into subcategories and categories. A subset of early phase endpoints relevant to the respiratory subgroup was selected for further investigation. The variability of the outcomes and the variability in reporting was investigated.

RESULTS

A total of 6905 references were retrieved and a total of 294 separate outcomes were identified from 58 studies. The outcomes were then classified into 11 categories and 66 subcategories. A subset of 22 outcomes relevant for the respiratory group were identified as potential early phase outcomes. The summary statistics, time points and definitions show the outcomes are analysed and reported in different ways.

CONCLUSION

The outcome measures were defined, analysed and reported in a variety of ways. This creates difficulties for synthesising data in systematic reviews and planning definitive trials. This review once again highlights an urgent need for standardisation and validation of surrogate outcomes reported in critical care trials. Future work should aim to validate and develop a core outcome set for surrogate outcomes in critical care trials.

Closed-loop ventilation

PURPOSE OF REVIEW

The last 25 years have seen considerable development in modes of closed-loop ventilation and there are now several of them commercially available. They not only offer potential benefits for the individual patient, but may also improve the organization within the intensive care unit (ICU). Clinicians are showing both greater interest and willingness to address the issues of a caregiver shortage and overload of bedside work in the ICU. This article reviews the clinical benefits of using closed-loop ventilation modes, with a focus on control of oxygenation, lung protection, and weaning.

RECENT FINDINGS

Closed-loop ventilation modes are able to maintain important physiological variables, such as oxygen saturation measured by pulse oximetry, tidal volume (VT), driving pressure (ΔP), and mechanical power (MP), within target ranges aimed at ensuring continuous lung protection. In addition, these modes adapt the ventilator support to the patient's needs, promoting diaphragm activity and preventing over-assistance. Some studies have shown the potential of these modes to reduce the duration of both weaning and mechanical ventilation.

SUMMARY

Recent studies have primarily demonstrated the safety, efficacy, and feasibility of using closed-loop ventilation modes in the ICU and postsurgery patients. Large, multicenter randomized controlled trials are needed to assess their impact on important short- and long-term clinical outcomes, the organization of the ICU, and cost-effectiveness.

Liberation from Mechanical Ventilation: Established and New Insights

A substantial proportion of critically ill patients require ventilator support with the majority requiring invasive mechanical ventilation. Timely and safe liberation from invasive mechanical ventilation is a critical aspect of patient care in the intensive care unit (ICU) and is a top research priority for patients and clinicians. In this article, we discuss how to (1) identify candidates for liberation from mechanical ventilation, (2) conduct spontaneous breathing trials (SBTs), and (3) optimize patients for liberation from mechanical ventilation. We also discuss the roles for (4) extubation to noninvasive ventilation and (5) newer modes of mechanical ventilation during liberation from mechanical ventilation. We conclude that, though substantial progress has been made in identifying patients who are likely to be liberated (e.g., through the use of SBTs) and management strategies that speed liberation from the ventilator (e.g., protocolized SBTs, lighter sedation, and early mobilization), many important questions regarding liberation from mechanical ventilation in clinical practice remain unanswered.

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

Automated weaning from mechanical ventilation: Results of a Bayesian network meta-analysis

PURPOSE

Mechanical ventilation (MV) weaning is a crucial step. Automated weaning modes reduce MV duration but the question of the best automated mode remains unanswered. Our objective was to compare the major automated modes for MV weaning in critically ill and post-operative adult patients.

MATERIAL AND METHODS

We conducted a network Bayesian meta-analysis to compare different automated modes. We searched MEDLINE, EMBASE and Cochrane central registry for randomized control trials comparing automated weaning modes either to another automated mode or to standard-of-care. The primary outcome was the duration of MV weaning extracted from the original trials.

RESULTS

663 articles were screened and 26 trials (2097patients) were included in the final analysis. All automated modes included in the study (ASV°, Intellivent ASV, Smartcare, Automode°, PAV° and MRV°) outperformed standard-of-care but no automated mode reduced the duration of mechanical ventilation weaning as compared to others in the network meta-analysis.

CONCLUSION

Compared to standard weaning practice, all automated modes significantly reduced the duration of MV weaning in critically ill and post-operative adult patients. When cross-compared using a network meta-analysis, no specific mode was different in reducing the duration of MV weaning. The study was registered in PROSPERO (CRD42015024742).

Adaptive mechanical ventilation with automated minimization of mechanical power-a pilot randomized cross-over study

BACKGROUND

Adaptive mechanical ventilation automatically adjusts respiratory rate (RR) and tidal volume (V_T) to deliver the clinically desired minute ventilation, selecting RR and V_T based on Otis' equation on least work of breathing. However, the resulting V_T may be relatively high, especially in patients with more compliant lungs. Therefore, a new mode of adaptive ventilation (adaptive ventilation mode 2, AVM2) was developed which automatically minimizes inspiratory power with the aim of ensuring lung-protective combinations of V_T and RR. The aim of this study was to investigate whether AVM2 reduces V_T, mechanical power, and driving pressure (ΔP_stat) and provides similar gas exchange when compared to adaptive mechanical ventilation based on Otis' equation.

METHODS

A prospective randomized cross-over study was performed in 20 critically ill patients on controlled mechanical ventilation, including 10 patients with acute respiratory distress syndrome (ARDS). Each patient underwent 1 h of mechanical ventilation with AVM2 and 1 h of adaptive mechanical ventilation according to Otis' equation (adaptive ventilation mode, AVM). At the end of each phase, we collected data on V_T, mechanical power, ΔP, PaO₂/FiO₂ ratio, PaCO₂, pH, and hemodynamics.

RESULTS

Comparing adaptive mechanical ventilation with AVM2 to the approach based on Otis' equation (AVM), we found a significant reduction in V_T both in the whole study population (7.2 ± 0.9 vs. 8.2 ± 0.6 ml/kg, p <  0.0001) and in the subgroup of patients with ARDS (6.6 ± 0.8 ml/kg with AVM2 vs. 7.9 ± 0.5 ml/kg with AVM, p <  0.0001). Similar reductions were observed for ΔP_stat (whole study population: 11.5 ± 1.6 cmH₂O with AVM2 vs. 12.6 ± 2.5 cmH₂O with AVM, p <  0.0001; patients with ARDS: 11.8 ± 1.7 cmH₂O with AVM2 and 13.3 ± 2.7 cmH₂O with AVM, p = 0.0044) and total mechanical power (16.8 ± 3.9 J/min with AVM2 vs. 18.6 ± 4.6 J/min with AVM, p = 0.0024; ARDS: 15.6 ± 3.2 J/min with AVM2 vs. 17.5 ± 4.1 J/min with AVM, p = 0.0023). There was a small decrease in PaO₂/FiO₂ (270 ± 98 vs. 291 ± 102 mmHg with AVM, p = 0.03; ARDS: 194 ± 55 vs. 218 ± 61 with AVM, p = 0.008) and no differences in PaCO₂, pH, and hemodynamics.

CONCLUSIONS

Adaptive mechanical ventilation with automated minimization of inspiratory power may lead to more lung-protective ventilator settings when compared with adaptive mechanical ventilation according to Otis' equation.

TRIAL REGISTRATION

The study was registered at the German Clinical Trials Register ( DRKS00013540 ) on December 1, 2017, before including the first patient.

A Randomized Controlled Trial of Noninvasive Ventilation with Pressure Support Ventilation and Adaptive Support Ventilation in Acute Exacerbation of COPD: A Feasibility Study

Whether the use of adaptive support ventilation (ASV) during noninvasive ventilation (NIV) is as effective as pressure support ventilation (PSV) remains unknown. In this exploratory study, we compared the delivery of NIV with PSV vs. ASV. We randomized consecutive subjects with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) to receive NIV either with the PSV or the ASV mode. The primary outcome was NIV failure (endotracheal intubation, re-institution of NIV within 48 h of discontinuation or mortality). The secondary outcomes were the duration of mechanical ventilation (invasive and noninvasive), the number of NIV manipulations, the visual analogue score (VAS) for physician's ease of use and patient's comfort, and the complications of NIV use. We enrolled 74 subjects (n = 38, PSV; n = 36, ASV; 78.4% males) with a mean (SD) age of 60.5 (9.5) years. The baseline characteristics were similar between the two groups. The overall NIV failure rate was 28.4% and was similar between the two groups (PSV vs. ASV: 34.2% vs. 22.2%, p = 0.31). There was a 9% reduction in the intubation rate with ASV. There were six deaths (PSV vs. ASV: 2 vs 4, p =0.311). There was no difference in the secondary outcomes. The application of NIV using ASV was associated with a similar success rate as PSV in subjects with AECOPD. Due to the small sample size, the results of our study should be confirmed in a larger trial. Trial registry: ww.clinicaltrials.gov (NCT02877524).

An open-loop, physiological model based decision support system can reduce pressure support while acting to preserve respiratory muscle function

PURPOSE

To assess whether a clinical decision support system (CDSS) suggests PS and FIO₂ maintaining appropriate breathing effort, and minimizing FIO₂.

MATERIALS

Prospective, cross-over study in PS ventilated ICU patients. Over support (150% baseline) and under support (50% baseline) were applied by changing PS (15 patients) or PEEP (8 patients). CDSS advice was followed. Tension time index of inspiratory muscles (TTies), respiratory and metabolic variables were measured.

RESULTS

PS over support (median 8.0 to 12.0 cmH₂O) reduced respiratory muscle activity (TTies 0.090 ± 0.028 to 0.049 ± 0.030; p < .01), and tended to increase tidal volume (VT: 8.6 ± 3.0 to 10.1 ± 2.9 ml/kg; p = .08). CDSS advice reduced PS (6.0 cmH₂O, p = .005), increased TTies (0.076 ± 0.038, p < .01), and tended to reduce VT (8.9 ± 2.4 ml/kg, p = .08). PS under support (12.0 to 4.0 cmH₂O) slightly increased respiratory muscle activity, (TTies to 0.120 ± 0.044; p = .007) with no significant CDSS advice. CDSS advice reduced FIO₂ by 12-14% (p = .005), resulting in median SpO₂ = 96% (p < .02). PEEP changes did not result in changes in physiological variables, or CDSS advice.

CONCLUSION

The CDSS advised on low values of PS often not prohibiting extubation, while acting to preserve respiratory muscle function and preventing passive lung inflation. CDSS advice minimized FIO₂ maintaining SpO₂ at safe and beneficial values.

Les systèmes automatisés de sevrage de la ventilation mécanique ont-ils une place en pratique clinique ?

Du fait de la stagnation de l’offre démographique médicale et du vieillissement de la population, les besoins en ventilation mécanique vont croître dans les années à venir. Dans ce contexte, la conduite du sevrage de la ventilation mécanique par des systèmes automatisés est une perspective séduisante, permettant d’épargner du temps médical et infirmier. La gestion du sevrage par des systèmes automatisés repose sur l’utilisation de l’intelligence artificielle incorporée au sein de ventilateurs capables de détecter précocement la sevrabilité des patients puis d’entreprendre le cas échéant une épreuve de ventilation spontanée. Deux systèmes répondant à ce cahier des charges sont actuellement commercialisés. Bien que les données disponibles soient peu nombreuses, celles-ci semblent justifier l’intérêt pour ces systèmes en montrant au pire une équivalence, au mieux une réduction dans la durée du sevrage, lorsqu’ils sont comparés à une démarche de sevrage conventionnelle. Les défis de demain seront de tester la généralisation de ces systèmes dans la pratique clinique et de définir les caractéristiques des populations susceptibles d’en bénéficier le plus.

Automated control of mechanical ventilation during general anaesthesia: study protocol of a bicentric observational study (AVAS)

INTRODUCTION

Automated control of mechanical ventilation during general anaesthesia is not common. A novel system for automated control of most of the ventilator settings was designed and is available on an anaesthesia machine.

METHODS AND ANALYSIS

The 'Automated control of mechanical ventilation during general anesthesia study' (AVAS) is an international investigator-initiated bicentric observational study designed to examine safety and efficacy of the system during general anaesthesia. The system controls mechanical breathing frequency, inspiratory pressure, pressure support, inspiratory time and trigger sensitivity with the aim to keep a patient stable in user adoptable target zones. Adult patients, who are classified as American Society of Anesthesiologists physical status I, II or III, scheduled for elective surgery of the upper or lower limb or for peripheral vascular surgery in general anaesthesia without any additional regional anaesthesia technique and who gave written consent for study participation are eligible for study inclusion. Primary endpoint of the study is the frequency of specifically defined adverse events. Secondary endpoints are frequency of normoventilation, hypoventilation and hyperventilation, the time period between switch from controlled ventilation to assisted ventilation, achievement of stable assisted ventilation of the patient, proportion of time within the target zone for tidal volume, end-tidal partial pressure of carbon dioxide as individually set up for each patient by the user, frequency of alarms, frequency distribution of tidal volume, inspiratory pressure, inspiration time, expiration time, end-tidal partial pressure of carbon dioxide and the number of re-intubations.

ETHICS AND DISSEMINATION

AVAS will be the first clinical study investigating a novel automated system for the control of mechanical ventilation on an anaesthesia machine. The study was approved by the ethics committees of both participating study sites. In case that safety and efficacy are acceptable, a randomised controlled trial comparing the novel system with the usual practice may be warranted.

TRIAL REGISTRATION

DRKS DRKS00011025, registered 12 October 2016; clinicaltrials.gov ID. NCT02644005, registered 30 December 2015.

Comparing the Effect of Adaptive Support Ventilation (ASV) and Synchronized Intermittent Mandatory Ventilation (SIMV) on Respiratory Parameters in Neurosurgical ICU Patients

BACKGROUND

Various modes of mechanical ventilation have different effects on respiratory variables. Lack of patients' neuro-ventilatory coordination and increasing the work of breathing are major disadvantages in mechanically ventilated patients.

OBJECTIVES

This study is conducted to compare the respiratory parameters differences in Adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) modes in neurosurgical ICU patients.

METHODS

In a crossover study, patients under mechanical ventilation in neurosurgical ICU were enrolled. The patients alternatively experienced two types of ventilations for 30 minutes (adaptive support ventilation and synchronized intermittent mandatory ventilation). The respiratory parameters (tidal volume, respiratory rate, airway pressure, lung compliance, end-tidal carbon dioxide, peripheral oxygenation and respiratory dead space), hemodynamic variables, every 10 minutes and arterial blood gas analysis at the end of each 30 minutes were recorded. Results were compared and analyzed with SPSS v.19.

RESULTS

Sixty patients were involved in this study. In ASV mode, values including peak airway pressure (P-peak), end-tidal carbon dioxide (EtCO2), tidal volume and respiratory dead space were significantly lower than SIMV mode. Although the mean value for dynamic compliance had no significant difference in the two types of ventilation, it was better in ASV mode.

CONCLUSIONS

ASV mode compared with SIMV mode can lead to improve lung compliance and respiratory dead space.

Comparing the effects of adaptive support ventilation and synchronized intermittent mandatory ventilation on intubation duration and hospital stay after coronary artery bypass graft surgery

Background:

Different modes of mechanical ventilation are used for respiratory support after coronary artery bypass graft (CABG). This study aimed to compare the effect(s) of using adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) on the length of mechanical ventilation (intubation duration) and hospital stay after coronary artery bypass graft surgery.

Materials and Methods:

In a randomized control trial, 64 patients were ventilated with ASV as the experiment group or with SIMV as the control group after CABG surgery in Chamran Hospital of Isfahan University of Medical Sciences. The time of tracheal intubation and the length of hospital stay were compared between the two groups. Data were analyzed and described using statistical analysis (independent t-test).

Results:

The mean time of intubation duration was significantly lower in ASV group compared with SIMV group. (4.83 h vs 6.71 h, P < 0.001). The lengths of hospital stay in the ASV and the SIMV groups were 140.6 h and 145.1 h, respectively. This difference was significant between the two groups (P = 0.006).

Conclusions:

According to the results of this study, using ASV mode for mechanical ventilation after CABG led to a decrease in intubation duration and also hospital stay in comparison with the SIMV group. It is recommended to use ASV mode on ventilators for respiratory support of patients undergoing coronary artery bypass graft surgery.