Automated Weaning from Mechanical Ventilation after Off-Pump Coronary Artery Bypass Grafting

Effects of Automated Versus Conventional Ventilation on Quality of Oxygenation-A Substudy of a Randomized Crossover Clinical Trial

Background/Objectives: Attaining adequate oxygenation in critically ill patients undergoing invasive ventilation necessitates intense monitoring through pulse oximetry (SpO2) and frequent manual adjustments of ventilator settings like the fraction of inspired oxygen (FiO2) and the level of positive end-expiratory pressure (PEEP). Our aim was to compare the quality of oxygenation with the use of automated ventilation provided by INTELLiVENT-Adaptive Support Ventilation (ASV) vs. ventilation that is not automated, i.e., conventional pressure-controlled or pressure support ventilation. Methods: A substudy within a randomized crossover clinical trial in critically ill patients under invasive ventilation. The primary endpoint was the percentage of breaths in an optimal oxygenation zone, defined by predetermined levels of SpO2, FiO2, and PEEP. Secondary endpoints were the percentage of breaths in acceptable or critical oxygenation zones, the percentage of time spent in optimal, acceptable, and critical oxygenation zones, the number of manual interventions at the ventilator, and the number and duration of ventilator alarms related to oxygenation. Results: Of the 96 patients included in the parent study, 53 were eligible for this current subanalysis. Among them, 31 patients were randomized to start with automated ventilation, while 22 patients began with conventional ventilation. No significant differences were found in the percentage of breaths within the optimal zone between the two ventilation modes (median percentage of breaths during automated ventilation 19.4 [0.1-99.9]% vs. 25.3 [0.0-100.0]%; p = 0.963). Similarly, there were no differences in the percentage of breaths within the acceptable and critical zones, nor in the time spent in the three predefined oxygenation zones. Although the number of manual interventions was lower with automated ventilation, the number and duration of ventilator alarms were fewer with conventional ventilation. Conclusions: The quality of oxygenation with automated ventilation is not different from that with conventional ventilation. However, while automated ventilation comes with fewer manual interventions at the ventilator, it also comes with more ventilator alarms.

Recommendations for fast-track extubation in adult cardiac surgery patients: a consensus statement

INTRODUCTION

Enhanced recovery after cardiac surgery in selected low-risk patients, has the potential to improve outcomes and reduce the burden of healthcare costs. Anesthesia-related challenges play a major role in the successful implementation of Enhanced Recovery After Surgery (ERAS) protocols, with particular emphasis placed on fast-track extubation. Acknowledging the importance of this practice, the Italian Association of Cardiac Anesthesiologists and Intensive Care (ITACTAIC) has advocated for an initiative to establish a consensus offering practical recommendations for fast-track extubation after adult cardiac surgery.

EVIDENCE ACQUISITION

After conducting a systematic review, all randomised control trials (RCTs) published between 2013 and 2023 were meticulously selected and analysed during a consensus meeting that involved statement voting.

EVIDENCE SYNTHESIS

Out of the 2268 publications identified using the search string, 60 RCTs were selected and classified into six groups, each evaluating specific interventions associated with extubation within 6 hours post-surgery. The authors examined 20 RCTs pertaining to loco-regional anesthesia, 19 analysing elements of general anesthesia, 12 focused on surgery-related aspects and techniques, three examining ventilation, two exploring anesthesia depth monitoring, and four addressing miscellaneous aspects. The expert panel approved 16 statements with 15 achieving high agreement and one obtaining moderate agreement. Finally a total of eight interventions were considered associated with fast-track extubation: parasternal block, erector spinae plane block, alpha agonist in the operating room (OR), opioids in the OR, dexmedetomidine in the intensive care unit (ICU), minimal invasive surgical access, anesthesia depth monitoring, adaptative support ventilation.

CONCLUSIONS

In the first consensus document ever published by a scientific society addressing practical recommendations for fast-track extubation post-cardiac surgery, the authors identified sixteen interventions commonly associated with fast-track extubation in selected adult cardiac surgery patients.

Effectiveness of Adaptive Support Ventilation in Facilitating Weaning from Mechanical Ventilation in Postoperative Patients

OBJECTIVE

This meta-analysis aims to evaluate the effectiveness of adaptive support ventilation (ASV) in facilitating postoperative weaning from mechanical ventilation in cardiac surgery patients.

DESIGN

A systematic review and meta-analysis to assess ASV in weaning postoperative cardiac surgery patients. Outcomes included early extubation, reintubation rates, time to extubation, and lengths of intensive care units and hospital stays.

SETTING

We searched electronic databases from inception to March 2023 and included randomized controlled trials that compared ASV with conventional ventilation methods in this population.

PARTICIPANTS

Postoperative cardiac surgery patients.

MEASUREMENTS AND MAIN RESULTS

A random effects model was used for meta-analysis, and trial sequential analysis (TSA) was conducted to assess result robustness. The meta-analysis included 11 randomized controlled trials with a total of 1027 randomized patients. ASV was associated with a shorter time to extubation compared to conventional ventilation (random effects, mean difference -68.30 hours; 95% confidence interval, -115.50 to -21.09) with TSA providing a conclusive finding. While ASV indicated improved early extubation rates, no significant differences were found in reintubation rates or lengths of intensive care unit and hospital stays, with these TSA results being inclusive.

CONCLUSIONS

ASV appears to facilitate a shorter time to extubation in postoperative cardiac surgery patients compared to conventional ventilation, suggesting benefits in accelerating the weaning process and reducing mechanical ventilation duration.

Pain and sleep after open-heart surgery-inhalation peppermint essence: double-blind randomized clinical trial

OBJECTIVE

The aim of this study was to determine the effect of inhaling peppermint essence on pain relief and sleep quality after open-heart surgery.

METHODS

In a double-blind randomised clinical trial carried out in Iran in 2020, 64 cardiac patients were selected by convenience sampling and randomly allocated to aromatherapy (n=32) and placebo (n=32) groups. The aromatherapy and control groups received inhaled aromatherapy using peppermint essence and distilled water, respectively. Data gathering tools were the Numeric Pain Rating Scale and St Mary's Hospital Sleep Questionnaire. Data were analysed using an independent t-test, χ2 test, Mann-Whitney U test and generalised estimating equation analysis.

RESULTS

The mean severity of pain in the aromatherapy and placebo groups was 3.22±0.88 and 4.56±0.90, respectively, which was a statistically significant difference (p=0.0001). The mean sleep scores after the intervention on day 1 were 20.10±4.90 and 25.76±6.36 in the aromatherapy and placebo groups, respectively, and 18.63±5.56 and 22.62±5.69, respectively, on day 2. The difference between the two groups was statistically significantly different after the intervention in terms of sleep quality (p<0.05).

CONCLUSION

Aromatherapy attenuated pain and improved sleep quality after open-heart surgery. Peppermint essence aromatherapy is therefore recommended after surgery.

The Evolution of Intermittent Mandatory Ventilation

Intermittent mandatory ventilation (IMV) is one kind of breath sequence used to classify a mode of ventilation. IMV is defined as the ability for spontaneous breaths (patient triggered and patient cycled) to exist between mandatory breaths (machine triggered or machine cycled). Over the course of more than a century, IMV has evolved into 4 distinct varieties, each with its own advantages and disadvantages in serving the goals of mechanical ventilation (ie, safety, comfort, and liberation). The purpose of this paper is to describe the evolution of IMV, review relevant supporting evidence, and discuss the rationales for each of the 4 varieties. Also included is a brief overview of the background information required for a proper perspective of the purpose and design of the innovations. Understanding these different forms of IMV is essential to recognizing the similarities and differences among many dozens of different modes of ventilation. This recognition is important for clinical application, education of caregivers, and research in mechanical ventilation.

Effect of Automated Closed-loop ventilation versus convenTional VEntilation on duration and quality of ventilation in critically ill patients (ACTiVE) - study protocol of a randomized clinical trial

BACKGROUND

INTELLiVENT-Adaptive Support Ventilation (ASV) is a fully automated closed-loop mode of ventilation for use in critically ill patients. Evidence for benefit of INTELLiVENT-ASV in comparison to ventilation that is not fully automated with regard to duration of ventilation and quality of breathing is largely lacking. We test the hypothesis that INTELLiVENT-ASV shortens time spent on a ventilator and improves the quality of breathing.

METHODS

The "Effects of Automated Closed-loop VenTilation versus Conventional Ventilation on Duration and Quality of Ventilation" (ACTiVE) study is an international, multicenter, two-group randomized clinical superiority trial. In total, 1200 intensive care unit (ICU) patients with an anticipated duration of ventilation of > 24 h will be randomly assigned to one of the two ventilation strategies. Investigators screen patients aged 18 years or older at start of invasive ventilation in the ICU. Patients either receive automated ventilation by means of INTELLiVENT-ASV, or ventilation that is not automated by means of a conventional ventilation mode. The primary endpoint is the number of days free from ventilation and alive at day 28; secondary endpoints are quality of breathing using granular breath-by-breath analysis of ventilation parameters and variables in a time frame of 24 h early after the start of invasive ventilation, duration of ventilation in survivors, ICU and hospital length of stay (LOS), and mortality rates in the ICU and hospital, and at 28 and 90 days.

DISCUSSION

ACTiVE is one of the first randomized clinical trials that is adequately powered to compare the effects of automated closed-loop ventilation versus conventional ventilation on duration of ventilation and quality of breathing in invasively ventilated critically ill patients. The results of ACTiVE will support intensivist in their choices regarding the use of automated ventilation.

TRIAL REGISTRATION

ACTiVE is registered in clinicaltrials.gov (study identifier: NCT04593810 ) on 20 October 2020.

Development and Validation of a Machine-Learning Model for Prediction of Extubation Failure in Intensive Care Units

Background: Extubation failure (EF) can lead to an increased chance of ventilator-associated pneumonia, longer hospital stays, and a higher mortality rate. This study aimed to develop and validate an accurate machine-learning model to predict EF in intensive care units (ICUs). Methods: Patients who underwent extubation in the Medical Information Mart for Intensive Care (MIMIC)-IV database were included. EF was defined as the need for ventilatory support (non-invasive ventilation or reintubation) or death within 48 h following extubation. A machine-learning model called Categorical Boosting (CatBoost) was developed based on 89 clinical and laboratory variables. SHapley Additive exPlanations (SHAP) values were calculated to evaluate feature importance and the recursive feature elimination (RFE) algorithm was used to select key features. Hyperparameter optimization was conducted using an automated machine-learning toolkit (Neural Network Intelligence). The final model was trained based on key features and compared with 10 other models. The model was then prospectively validated in patients enrolled in the Cardiac Surgical ICU of Zhongshan Hospital, Fudan University. In addition, a web-based tool was developed to help clinicians use our model. Results: Of 16,189 patients included in the MIMIC-IV cohort, 2,756 (17.0%) had EF. Nineteen key features were selected using the RFE algorithm, including age, body mass index, stroke, heart rate, respiratory rate, mean arterial pressure, peripheral oxygen saturation, temperature, pH, central venous pressure, tidal volume, positive end-expiratory pressure, mean airway pressure, pressure support ventilation (PSV) level, mechanical ventilation (MV) durations, spontaneous breathing trial success times, urine output, crystalloid amount, and antibiotic types. After hyperparameter optimization, our model had the greatest area under the receiver operating characteristic (AUROC: 0.835) in internal validation. Significant differences in mortality, reintubation rates, and NIV rates were shown between patients with a high predicted risk and those with a low predicted risk. In the prospective validation, the superiority of our model was also observed (AUROC: 0.803). According to the SHAP values, MV duration and PSV level were the most important features for prediction. Conclusions: In conclusion, this study developed and prospectively validated a CatBoost model, which better predicted EF in ICUs than other models.

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).

Fully automated postoperative ventilation in cardiac surgery patients: a randomised clinical trial

BACKGROUND

Ensuring that lung-protective ventilation is achieved at scale is challenging in perioperative practice. Fully automated ventilation may be more effective in delivering lung-protective ventilation. Here, we compared automated lung-protective ventilation with conventional ventilation after elective cardiac surgery in haemodynamically stable patients.

METHODS

In this single-centre investigator-led study, patients were randomly assigned at the end of cardiac surgery to receive either automated (adaptive support ventilation) or conventional ventilation. The primary endpoint was the proportion of postoperative ventilation time characterised by exposure to predefined optimal, acceptable, and critical (injurious) ventilatory parameters in the first three postoperative hours. Secondary outcomes included severe hypoxaemia (Spo₂ <85%) and resumption of spontaneous breathing. Data are presented as mean (95% confidence intervals [CIs]).

RESULTS

We randomised 220 patients (30.4% females; age: 62-76 yr). Subjects randomised to automated ventilation (n=109) spent a 29.7% (95% CI: 22.1-37.4) higher mean proportion of postoperative ventilation time receiving optimal postoperative ventilation after surgery (P<0.001) compared with subjects receiving conventional postoperative ventilation (n=111). Automated ventilation also reduced the proportion of postoperative ventilation time that subjects were exposed to injurious ventilatory settings by 2.5% (95% CI: 1-4; P=0.003). Severe hypoxaemia was less likely in subjects randomised to automated ventilation (risk ratio: 0.26 [0.22-0.31]; P<0.01). Subjects resumed spontaneous breathing more rapidly when randomised to automated ventilation (hazard ratio: 1.38 [1.05-1.83]; P=0.03).

CONCLUSIONS

Fully automated ventilation in haemodynamically stable patients after cardiac surgery optimised lung-protective ventilation during postoperative ventilation, with fewer episodes of severe hypoxaemia and an accelerated resumption of spontaneous breathing.

CLINICAL TRIAL REGISTRATION

NCT03180203.

Protective ventilation from ICU to operating room: state of art and new horizons

The prevention of ventilator-associated lung injury (VALI) and postoperative pulmonary complications (PPC) is of paramount importance for improving outcomes both in the operating room and in the intensive care unit (ICU). Protective respiratory support includes a wide spectrum of interventions to decrease pulmonary stress-strain injuries. The motto 'low tidal volume for all' should become routine, both during major surgery and in the ICU, while application of a high positive end-expiratory pressure (PEEP) strategy and of alveolar recruitment maneuvers requires a personalized approach and requires further investigation. Patient self-inflicted lung injury is an important type of VALI, which should be diagnosed and mitigated at the early stage, during restoration of spontaneous breathing. This narrative review highlights the strategies used for protective positive pressure ventilation. The emerging concepts of damaging energy and power, as well as pathways to personalization of the respiratory settings, are discussed in detail. In the future, individualized approaches to protective ventilation may involve multiple respiratory settings extending beyond low tidal volume and PEEP, implemented in parallel with quantifying the risk of VALI and PPC.

Effect of Cold Application on Chest Incision Pain Due to Deep Breathing and Cough Exercises

BACKGROUND

We determined the effect of cold application after coronary artery bypass graft surgery on chest incision pain due to deep breathing and coughing exercises. Thoracotomy performed for coronary artery bypass graft surgery is one of the most painful surgical procedures. This pain prevents deep breathing and effective coughing. These problems increase the risk of morbidity in the postoperative period.

AIMS

This study aimed to determine the effect of cold application after CABG surgery on chest incision pain due to deep breathing and cough exercises.

DESIGN

Experimental study with control group and repeated measurements.

SETTINGS

Patients were selected through convenience sampling in the Cardiovascular Surgery Intensive Care Unit at a hospital.

PARTICIPANTS

The study was conducted with 57 patients who underwent open heart surgery (29 and 28 in the experimental and control groups, respectively).

METHODS

Repeated pain assessment was performed before, immediately after, and 5 min after deep breathing and coughing exercises performed in 4 periods at 2-h intervals. The first pain assessment was performed 24 h postoperatively. In the first and third assessments of the experimental group, pain was recorded before the exercise; the exercise was performed 15 min after cold gel pack application to the incision area. Pain was assessed before, immediately after, and 5 min after exercise using the Short- Form McGill Melzack Pain Questionnaire.

RESULTS

Reduction in pain severity within and between the groups was statistically significant in the first and third evaluations (p = .001).

CONCLUSIONS

The results provide evidence to support the use of cold gel pack.

Assessment and pathophysiology of pain in cardiac surgery

Analysis of the problem of surgical pain is important in view of the fact that the success of surgical treatment depends largely on proper pain management during the first few days after a cardiosurgical procedure. Postoperative pain is due to intraoperative damage to tissue. It is acute pain of high intensity proportional to the type of procedure. The pain is most intense during the first 24 hours following the surgery and decreases on subsequent days. Its intensity is higher in younger subjects than elderly and obese patients, and preoperative anxiety is also a factor that increases postoperative pain. Ineffective postoperative analgesic therapy may cause several complications that are dangerous to a patient. Inappropriate postoperative pain management may result in chronic pain, immunosuppression, infections, and less effective wound healing. Understanding and better knowledge of physiological disorders and adverse effects resulting from surgical trauma, anesthesia, and extracorporeal circulation, as well as the development of standards for intensive postoperative care units are critical to the improvement of early treatment outcomes and patient comfort.

Investigation on Risk Factors of Ventilator-Associated Pneumonia in Acute Cerebral Hemorrhage Patients in Intensive Care Unit

Ventilator-associated pneumonia (VAP) is a predominant factor of pulmonary infection. We analyzed the risk factors of VAP with acute cerebral hemorrhage in intensive care unit (ICU) by univariate and multivariate logistic regression analyses. After comparison of 197 cases of the VAP and non-VAP patients, we found that age > 65 years (P = 0.003), smoke (P = 0.003), coronary heart disease (P = 0.005), diabetes (P = 0.001), chronic obstructive pulmonary disease (COPD) (P = 0.002), ICU and hospital stay (P = 0.01), and days on mechanical ventilation (P = 0.01) were significantly different, indicating that they are risk factors of VAP. All the age > 65 years (OR = 3.350, 95% CI = 1.936–5.796, P ≤ 0.001), smoke (OR = 3.206, 95% CI = 1.909–5.385, P ≤ 0.001), coronary heart disease (OR = 3.179, 95% CI = 1.015–4.130, P = 0.017), diabetes (OR = 5.042, 95% CI = 3.518–7.342, P ≤ 0.001), COPD (OR = 1.942, 95% CI = 1.258–2.843, P = 0.012), ICU and hospital stay (OR = 2.34, 95% CI = 1.145–3.892, P = 0.038), and days on mechanical ventilation (OR = 1.992, 95% CI = 1.107–3.287, P = 0.007) are independent risk factors of VAP. After observation of patients with 6 months of follow-up, the BI score was significantly lower in VAP than that in non-VAP, and the rebleeding rate and mortality rate were significantly higher in VAP than those in non-VAP. Thus, the prognosis of the patients with acute cerebral hemorrhage and VAP in ICU is poor.