Variables predicting weaning outcome in prolonged mechanically ventilated tracheotomized patients: a retrospective study

Development of a machine learning model for prediction of the duration of unassisted spontaneous breathing in patients during prolonged weaning from mechanical ventilation

PURPOSE

Treatment of patients undergoing prolonged weaning from mechanical ventilation includes repeated spontaneous breathing trials (SBTs) without respiratory support, whose duration must be balanced critically to prevent over- and underload of respiratory musculature. This study aimed to develop a machine learning model to predict the duration of unassisted spontaneous breathing.

MATERIALS AND METHODS

Structured clinical data of patients from a specialized weaning unit were used to develop (1) a classifier model to qualitatively predict an increase of duration, (2) a regressor model to quantitatively predict the precise duration of SBTs on the next day, and (3) the duration difference between the current and following day. 61 features, known to influence weaning, were included into a Histogram-based gradient boosting model. The models were trained and evaluated using separated data sets.

RESULTS

18.948 patient-days from 1018 individual patients were included. The classifier model yielded an ROC-AUC of 0.713. The regressor models displayed a mean absolute error of 2:50 h for prediction of absolute durations and 2:47 h for day-to-day difference.

CONCLUSIONS

The developed machine learning model showed informed results when predicting the spontaneous breathing capacity of a patient in prolonged weaning, however lacking prognostic quality required for direct translation to clinical use.

Psychosocial Predictors of Ventilator weaning Outcomes among patients in intensive care units

Background

Ventilator weaning is a process of discontinuing mechanical ventilation and transitioning patients to independent breathing after a period of mechanical support. Weaning outcomes among the critically ill in intensive care units (ICUs) vary significantly among individuals, leading to considerable variation in healthcare costs, length of hospital stay, morbidity and mortality. Addressing psychosocial aspects of care can improve weaning outcomes.

Objective

This study aimed to determine the effect of psychosocial factors (social support, family/significant other support, ability to communicate) on weaning outcome within intensive care patients. This research hypothesized that psychological and social factors play a role in determining ventilator weaning outcomes among ICU patients.

Methods

This study used a longitudinal, retrospective research design to analyze positive and negative psychosocial predictors of ventilator weaning outcomes. Data collection methods include interviews and questionnaires with patients and their families, as well as clinical data from the patient's medical records.

Results

presence of anxiety, depression, and hallucinations, have a negative relationship with weaning outcomes regarding a patient's psychological characteristics (rs = -0.207, -0.163, -0.158), while communication with a patient during mechanical ventilation have a positive relationship with weaning outcomes regarding a patient's psychological characteristics (rs = 0.152; p ≤ 0.05). Moreover patients who have fear during weaning trials, feeling neglected, and feeling insecurity have a negative relationship with weaning outcomes while gaining family support during mechanical ventilation have a positive relationship with weaning outcomes (rs = 0.144; p ≤ 0.05).Significance of results, the findings suggests that psychosocial factors, such as anxiety, depression, patient's perception of their illness, motivation to wean, and family involvement can influence the success of ventilator weaning among patients in ICUs.

Preoperative systemic immune-inflammation index may predict prolonged mechanical ventilation in patients with spontaneous basal ganglia intracerebral hemorrhage undergoing surgical operation

Background

Prolonged mechanical ventilation (PMV) has been proven as a risk factor for poor prognosis in patients with neurocritical illness. Spontaneous basal ganglia intracerebral hemorrhage (ICH) is one common subtype of hemorrhagic stroke and is associated with high morbidity and mortality. The systemic immune-inflammation index (SII) is used as a novel and valuable prognostic marker for various neoplastic diseases and other critical illnesses.

Objective

This study aimed to analyze the predictive value of preoperative SII for PMV in patients with spontaneous basal ganglia ICH who underwent surgical operations.

Methods

This retrospective study was conducted in patients with spontaneous basal ganglia ICH who underwent surgical operations between October 2014 and June 2021. SII was calculated using the following formula: SII = platelet count × neutrophil count/lymphocyte count. Multivariate logistic regression analysis and receiver operating characteristics curve (ROC) were used to evaluate the potential risk factors of PMV after spontaneous basal ganglia ICH.

Results

A total of 271 patients were enrolled. Of these, 112 patients (47.6%) presented with PMV. Multivariate logistic regression analysis showed that preoperative GCS (OR, 0.780; 95% CI, 0.688-0.883; P < 0.001), hematoma size (OR, 1.031; 95% CI, 1.016-1.047; P < 0.001), lactic acid (OR, 1.431; 95% CI, 1.015-2.017; P = 0.041) and SII (OR, 1.283; 95% CI, 1.049-1.568; P = 0.015) were significant risk factors for PMV. The area under the ROC curve (AUC) of SII was 0.662 (95% CI, 0.595-0.729, P < 0.001), with a cutoff value was 2,454.51.

Conclusion

Preoperative SII may predict PMV in patients with spontaneous basal ganglia ICH undergoing a surgical operation.

Long-term sleep apnea CPAP via tracheostomy in children with tracheomalacia: 20-year experience

Introduction

Children with severe tracheobronchomalacia may need placements of tracheostomies and long-term mechanical ventilation. Due to financial constraints, continuous positive airway pressure (CPAP) machines commonly used to treat obstructive sleep apnea in adults have been utilized to deliver positive distending pressure to such children at our institution for more than 20 years with favorable outcomes. We, therefore, reported our experience with 15 children using this machine.

Methods

This is a retrospective study during 2001-2021.

Results

Fifteen children, 9 boys, aged ranged 3 months-5.6 years, were discharged home with CPAP via tracheostomies. All had co-morbidities including gastroesophageal reflux (n = 9, 60%), neuromuscular disorders (n = 6, 40%), genetic abnormalities (n = 6, 40%), cardiac diseases (n = 4, 27%) and chronic lungs (n = 3, 20%). Eight (53%) children were aged less than 1 year old. The smallest child was aged 3 months old, weighing 4.9 kg. All caregivers were relatives and non-medical health professionals. The 1-month and 1-year readmission rates were 13% and 66% respectively. No factor-associated unfavorable outcomes were statistically identified. No complications related to CPAP malfunction were found. Five (33%) were weaned off CPAP, and 3 died (2 from sepsis and 1 from a sudden unknown cause).

Conclusion

We first reported the use of sleep apnea CPAP via tracheostomy in children with severe tracheomalacia. In limited-resource countries, this simple device may be another option for long-term invasive ventilatory support. The CPAP use in children with tracheobronchomalacia requires adequately trained caregivers.

Factors Affecting Mechanical Ventilator Weaning Success and 28-Day Survival Among Patients With Acute Respiratory Distress Syndrome Secondary to COVID-19

Introduction

The process of weaning patients off mechanical ventilation (MV) is difficult and complex. Critical care nurses must maintain continuity of care for patients undergoing MV weaning, assess patients' overall condition, and meet patients' needs.

Objectives

The study aimed to explore clinical factors of MV weaning success and 28-day survival among patients with acute respiratory distress syndrome secondary to COVID-19.

Methods

This prospective observational study was conducted on 90 newly admitted patients in the general intensive care unit Assiut Univeristy Main Hospital in Egypt from October 2021 to March 2022. The researchers applied a standard weaning protocol for all of the patients in this study and then assessed the outcome variables: success or failure of weaning trials from a mechanical ventilator, and 28-day survival.

Results

In total, 50 (55.6%) patients were successfully weaned from MV, and 45 (50%) patients survived at 28 days. In a multivariate regression analysis, dynamic compliance (OR, 1.115; 95% CI, 1.010-1.230, p = .031*), lymphocyte count (OR, 3.025; 95% CI, 1.322-6.923, p = .009*), urine output (OR, 1.002; 95% CI, 1.001-1.004, p = .002*), and alanine aminotransferase (ALT; OR, 0.993; 95% CI, 0.988-0.999, p = .017*) were significantly associated with weaning success. In addition, age (OR, 1.058; 95% CI, 1.015-1.102; p = .007*), lymphocyte count (OR, 3.304; 95% CI, 1.348-8.100; p = .009*), urine output (OR, 1.003; 95% CI, 1.001-1.004; p = .001*), and ALT (OR, 0.994; 95% CI, 0.989-0.99, p = .015*) were significantly associated with survival at 28 days.

Conclusion

Dynamic lung compliance, lymphocyte count, urine output, and ALT were found to be predictive parameters that may affect the success of weaning off MV. Additionally, it was found that age, lymphocyte count, urine output, and ALT are predictors of survival at 28 days. We recommend further studies with larger, more systematic samples and complete follow-up, focusing on pulmonary function and quality of life in postweaning patients with acute respiratory distress syndrome.

Development and validation of a mechanical power-oriented prediction model of weaning failure in mechanically ventilated patients: a retrospective cohort study

OBJECTIVE

To develop and validate a mechanical power (MP)-oriented prediction model of weaning failure in mechanically ventilated patients.

DESIGN

A retrospective cohort study.

SETTING

Data were collected from the large US Medical Information Mart for Intensive Care-IV (MIMIC-IV) V.1.0, which integrates comprehensive clinical data from 76 540 intensive care unit (ICU) admissions from 2008 to 2019.

PARTICIPANTS

A total of 3695 patients with invasive mechanical ventilation for more than 24 hours and weaned with T-tube ventilation strategies were enrolled from the MIMIC-IV database.

PRIMARY AND SECONDARY OUTCOME

Weaning failure.

RESULTS

All eligible patients were randomised into development cohorts (n=2586, 70%) and validation cohorts (n=1109, 30%). Multivariate logistic regression analysis of the development cohort showed that positive end-expiratory pressure, dynamic lung compliance, MP, inspired oxygen concentration, length of ICU stay and invasive mechanical ventilation duration were independent predictors of weaning failure. Calibration curves showed good correlation between predicted and observed outcomes. The prediction model showed accurate discrimination in the development and validation cohorts, with area under the receiver operating characteristic curve values of 0.828 (95% CI: 0.812 to 0.844) and 0.833 (95% CI: 0.809 to 0.857), respectively. Decision curve analysis indicated that the predictive model was clinically beneficial.

CONCLUSION

The MP-oriented model of weaning failure accurately predicts the risk of weaning failure in mechanical ventilation patients and provides valuable information for clinicians making decisions on weaning.

Mechanical power is associated with weaning outcome in critically ill mechanically ventilated patients

Several single-center studies have evaluated the predictive performance of mechanical power (MP) on weaning outcomes in prolonged invasive mechanical ventilation (IMV) patients. The relationship between MP and weaning outcomes in all IMV patients has rarely been studied. A retrospective study was conducted on MIMIC-IV patients with IMV for more than 24 h to investigate the correlation between MP and weaning outcome using logistic regression model and subgroup analysis. The discriminative ability of MP, MP normalized to dynamic lung compliance (C_dyn-MP) and MP normalized to predicted body weight (PBW-MP) on weaning outcome were evaluated by analyzing the area under the receiver-operating characteristic (AUROC). Following adjustment for confounding factors, compared with the reference group, the Odds Ratio of weaning failure in the maximum MP, C_dyn-MP, and PBW-MP groups increased to 3.33 [95%CI (2.04-4.53), P < 0.001], 3.58 [95%CI (2.27-5.56), P < 0.001] and 5.15 [95%CI (3.58-7.41), P < 0.001], respectively. The discriminative abilities of C_dyn-MP (AUROC 0.760 [95%CI 0.745-0.776]) and PBW-MP (AUROC 0.761 [95%CI 0.744-0.779]) were higher than MP (AUROC 0.745 [95%CI 0.730-0.761]) (P < 0.05). MP is associated with weaning outcomes in IMV patients and is an independent predictor of the risk of weaning failure. C_dyn-MP and PBW-MP showed higher ability in weaning failure prediction than MP.

The Impact of Higher Protein Intake in Patients with Prolonged Mechanical Ventilation

Prolonged mechanical ventilation (PMV) is associated with poor outcomes and a high economic cost. The association between protein intake and PMV has rarely been investigated in previous studies. This study aimed to investigate the impact of protein intake on weaning from mechanical ventilation. Patients with the PMV (mechanical ventilation ≥6 h/day for ≥21 days) at our hospital between December 2020 and April 2022 were included in this study. Demographic data, nutrition records, laboratory data, weaning conditions, and survival data were retrieved from the patient’s electronic medical records. A total of 172 patients were eligible for analysis. The patients were divided into two groups: weaning success (n = 109) and weaning failure (n = 63). Patients with daily protein intake greater than 1.2 g/kg/day had significant shorter median days of ventilator use than those with less daily protein intake (36.5 vs. 114 days, respectively, p < 0.0001). Daily protein intake ≥1.065 g/kg/day (odds ratio: 4.97, p = 0.033), daily protein intake ≥1.2 g/kg/day (odds ratio: 89.07, p = 0.001), improvement of serum albumin (odds ratio: 3.68, p = 0.027), and BMI (odds ratio: 1.235, p = 0.014) were independent predictor for successful weaning. The serum creatinine level in the 4th week remained similar in patients with daily protein intake either >1.065 g/kg/day or >1.2 g/kg/day (p = 0.5219 and p = 0.7796, respectively). Higher protein intake may have benefits in weaning in patients with PMV and had no negative impact on renal function.

Incidence, causes, and predictors of unsuccessful decannulation following prolonged weaning

Background

Liberation from prolonged tracheostomy ventilation involves ventilator weaning and removal of the tracheal cannula (referred to as decannulation). This study evaluated the incidence, causes, and predictors of unsuccessful decannulation following prolonged weaning.

Methods

Observational retrospective cohort study of 532 prolonged mechanically ventilated, tracheotomized patients treated at a specialized weaning center between June 2013 and January 2021. We summarized the causes for unsuccessful decannulations and used a binary logistic regression analysis to derive and validate associated predictors.

Results

Failure to decannulate occurred in 216 patients (41%). The main causes were severe intensive care unit (ICU)-acquired dysphagia (64%), long-term ventilator dependence following weaning failure (41%), excessive respiratory secretions (12%), unconsciousness (4%), and airway obstruction (3%). Predictors of unsuccessful decannulation from any cause were age [odds ratio (OR) = 1.04 year^-1; 95% confidence interval (CI), 1.02-1.06; p < 0.01], body mass index [0.96 kg/m² (0.93-1.00); p = 0.027], Acute Physiology and Chronic Health Evaluation II (APACHE-II) score [1.05 (1.00-1.10); p = 0.036], pre-existing non-invasive home ventilation [3.57 (1.51-8.45); p < 0.01], percutaneous tracheostomies [0.49 (0.30-0.80); p < 0.01], neuromuscular diseases [4.28 (1.21-15.1); p = 0.024], and total mechanical ventilation duration [1.02 day^-1 (1.01-1.02); p < 0.01]. Regression models examined in subsets of patients with severe dysphagia and long-term ventilator dependence as the main reason for failure revealed little overlapping among predictors, which even showed opposite effects on the outcome. The application of non-invasive ventilation as a weaning technique contributed to successful decannulation in 96 of 221 (43%) long-term ventilator-dependent patients following weaning failure.

Conclusion

Failure to decannulate after prolonged weaning occurred in 41%, mainly resulting from persistent ICU-acquired dysphagia and long-term ventilator dependence following weaning failure, each associated with its own set of predictors.

Specialized Weaning Unit in the Trajectory of SARS-CoV-2 ARDS: Influence of Limb Muscle Strength on Decannulation and Rehabilitation

BACKGROUND

Patients with ARDS due to COVID-19 may require tracheostomy and transfer to a weaning center. To date, data on the outcome of these patients are scarce. The objectives of this study were to determine the factors associated with time to decannulation and limb-muscle strength recovery.

METHODS

This was an observational retrospective study of subjects with COVID-19-related ARDS requiring tracheostomy after prolonged ventilation, who were subsequently transferred to a weaning center from April 4, 2020-May 30, 2020.

RESULTS

Forty-three subjects were included. Median age (interquartile range) was 61 (48-66) y; 81% were men, and median body mass index (BMI) was 30 (26-35) kg/m². Tracheostomy was performed after a median of 19 (12-27) d of mechanical ventilation, and the median ICU length of stay prior to transfer to the weaning center was 30 (21-46) d. On admission to the weaning center, the median Medical Research Council (MRC) score was 36 (27-44). Time to decannulation was 9 (7-18) d after admission to the weaning center. The only factor independently associated with early decannulation was the MRC score on admission to the weaning center (odds ratio 1.16 [95% CI 1.06-1.31], P = .005). Two factors were independently associated with MRC gain ≥ 10: BMI (odds ratio 0.88 [95% CI 0.76-0.99], P = .045) and MRC on admission (odds ratio 0.91 [95% CI 0.82-0.98], P = .03. Three months after admission to the weaning center, 40 subjects (93%) were weaned from mechanical ventilation and 36 (84%) had returned home.

CONCLUSIONS

MRC score at weaning center admission predicted both early decannulation and limb-muscle strength recovery.

Rehabilitation of Difficult-to-Wean, Tracheostomized Patients Admitted to Specialized Unit: Retrospective Analyses over 10-Years

Rehabilitation outcomes of difficult-to-wean tracheostomized patients have been reported in relatively small case studies and described for a limited time span. This study describes the characteristics and clinical outcomes of a large cohort of tracheostomized patients admitted to a specialized weaning unit over 10 years. We retrospectively analyzed data collected from January 2010 to December 2019 on difficult-to-wean tracheostomized patients who underwent comprehensive rehabilitation. Clinical characteristics collected at admission were the level of comorbidity (by the Cumulative Illness Rating Scale—CIRS) and the clinical severity (by the Simplified Acute Physiology Score—SAPS II). The proportions of patients weaned, decannulated, and able to walk; the change in autonomy level according to the Bristol Activities of Daily Living (BADL) Scale; and the setting of hospital discharge was assessed and compared in a consecutive 5-year time period (2010−2014 and 2015−2019) subgroup analysis. A total of 180 patients were included in the analysis. Patient anthropometry and preadmission clinical management in acute care hospitals were similar across years, but the categories of underlying diagnosis changed (p < 0.001) (e.g., chronic obstructive pulmonary disease—COPD—decreased), while the level of comorbidities increased (p = 0.003). The decannulation rate was 45.6%. CIRS and SAPS II at admission were both significant predictors of clinical outcomes. The proportion of patients whose gain in BADL score increased ≥ 2 points decreased over time. This study confirms the importance of rehabilitation in weaning units for the severely disabled subset of tracheostomized patients. Comorbidities and severity at admission are significantly associated with rehabilitation outcomes at discharge.

Effect of Family Presence on the Success of Weaning in Intensive Care Units

BACKGROUND

Weaning of the patient from mechanical ventilator is one of important stages of treatment in patients undergoing mechanical ventilation. Therefore, this study was done to determine the effect of family presence on weaning success in patients admitted to intensive care units (ICUs).

MATERIALS AND METHODS

The present interventional quasi-experimental study was performed on 154 patients undergoing mechanical ventilation who were selected through available sampling method and based on inclusion criteria and were randomly divided into intervention and control groups. For the intervention group, the presence of one of the family members was used in process of weaning from the mechanical ventilator. A questionnaire of patients' demographic information, family satisfaction of patients admitted to ICU, and a checklist of recording the patient's vital signs were used to collect the required information.

RESULTS

Based on the results, After the intervention, the patients in the intervention group were in a better condition than the control group in terms of vital signs, time spent for intubation and number of re-intubation, as well as family satisfaction (P<0.05).

CONCLUSION

The results showed that the presence of family in the process of weaning of patients admitted to the intensive care unit is effective in improving vital signs and physiological indicators and reduces the time spent for intubation and the number of re-intubation in these patients while promoting family satisfaction. Therefore, the use of this method can be used in coordination with members of the treatment team to help patients admitted to the intensive care unit.

Outcomes of prolonged intensive care and rehabilitation at a specialized multidisciplinary center in Sweden

BACKGROUND

Specialized clinics may improve the outcome for patients with prolonged intensive care stays. Admission may depend on diagnosis, need of respiratory support and more. We report the results from a Swedish specialized center with a multidisciplinary team approach to continued intensive care and simultaneous rehabilitation regardless of patients' primary diagnosis or ventilator need.

METHODS

All patients admitted and discharged from 2015 to 2018 were included. Demographics, diagnoses, ventilatory support requirement, discharge destination and survival were retrieved from the center´s quality registry.

RESULTS

A total of 181 patients, mean age 61 ± 16 years, 64% men, were analyzed. A neurological diagnosis was the cause for hospitalization in 46% of patients. Of the 55 patients admitted to the center for weaning from mechanical ventilation, 89% were successfully weaned within a median of 25 (interquartile range (IQR) 16-45) days. Decannulation was intended in 117 patients of which 90% were successful within a median of 25 (IQR 13-43) days. Readmission to intensive care was 4%. Most patients were discharged to their home or to rehabilitation clinics with a lower level of care. In-clinic mortality was 3%. Survival beyond 1 and 2 years after discharge was 79% and 70%, respectively.

CONCLUSION

Patients with prolonged intensive care and complex medical needs treated at a specialized center in Sweden had weaning and decannulation rates comparable to or better than previously reported. Mortality was low, and most patients were discharged home or for further rehabilitation. This was achieved with a multidisciplinary team approach to continued intensive care and simultaneous rehabilitation.

Mechanical power normalized to lung-thorax compliance indicates weaning readiness in prolonged ventilated patients

Since critical respiratory muscle workload is a significant determinant of weaning failure, applied mechanical power (MP) during artificial ventilation may serve for readiness testing before proceeding on a spontaneous breathing trial (SBT). Secondary analysis of a prospective, observational study in 130 prolonged ventilated, tracheotomized patients. Calculated MP’s predictive SBT outcome performance was determined using the area under receiver operating characteristic curve (AUROC), measures derived from k-fold cross-validation (likelihood ratios, Matthew's correlation coefficient [MCC]), and a multivariable binary logistic regression model. Thirty (23.1%) patients failed the SBT, with absolute MP presenting poor discriminatory ability (MCC 0.26; AUROC 0.68, 95%CI [0.59‒0.75], p = 0.002), considerably improved when normalized to lung-thorax compliance (LTC_dyn-MP, MCC 0.37; AUROC 0.76, 95%CI [0.68‒0.83], p < 0.001) and mechanical ventilation P_aCO₂ (so-called power index of the respiratory system [PI_rs]: MCC 0.42; AUROC 0.81 [0.73‒0.87], p < 0.001). In the logistic regression analysis, PI_rs (OR 1.48 per 1000 cmH₂O²/min, 95%CI [1.24‒1.76], p < 0.001) and its components LTC_dyn-MP (1.25 per 1000 cmH₂O²/min, [1.06‒1.46], p < 0.001) and mechanical ventilation P_aCO₂ (1.17 [1.06‒1.28], p < 0.001) were independently related to SBT failure. MP normalized to respiratory system compliance may help identify prolonged mechanically ventilated patients ready for spontaneous breathing.

Tracheal stenosis in prolonged mechanically ventilated patients: prevalence, risk factors, and bronchoscopic management

Background

Various complications may arise from prolonged mechanical ventilation, but the risk of tracheal stenosis occurring late after translaryngeal intubation or tracheostomy is less common. This study aimed to determine the prevalence, type, risk factors, and management of tracheal stenoses in mechanically ventilated tracheotomized patients deemed ready for decannulation following prolonged weaning.

Methods

A retrospective observational study on 357 prolonged mechanically ventilated, tracheotomized patients admitted to a specialized weaning center over seven years. Flexible bronchoscopy was used to discern the type, level, and severity of tracheal stenosis in each case. We described the management of these stenoses and used a binary logistic regression analysis to determine independent risk factors for stenosis development.

Results

On admission, 272 patients (76%) had percutaneous tracheostomies, and 114 patients (32%) presented mild to moderate tracheal stenosis following weaning completion, with a median tracheal cross-section reduction of 40% (IQR 25–50). The majority of stenoses (88%) were located in the upper tracheal region, most commonly resulting from localized granulation tissue formation at the site of the internal stoma (96%). The logistic regression analysis determined that obesity (OR 2.16 [95%CI 1.29–3.63], P < 0.01), presence of a percutaneous tracheostomy (2.02 [1.12–3.66], P = 0.020), and cricothyrotomy status (5.35 [1.96–14.6], P < 0.01) were independently related to stenoses. Interventional bronchoscopy with Nd:YAG photocoagulation was a highly effective first-line treatment, with only three patients (2.6%) ultimately referred to tracheal surgery.

Conclusions

Tracheal stenosis is commonly observed among prolonged ventilated patients with tracheostomies, characterized by localized hypergranulation and mild to moderate airway obstruction, with interventional bronchoscopy providing satisfactory results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01821-6.

Mechanical power normalized to lung-thorax compliance predicts prolonged ventilation weaning failure: a prospective study

Background

Mechanical power (MP) of artificial ventilation, the energy transferred to the respiratory system, is a chief determinant of adequate oxygenation and decarboxylation. Calculated MP, the product of applied airway pressure and minute ventilation, may serve as an estimate of respiratory muscle workload when switching to spontaneous breathing. The aim of the study was to assess MP’s discriminatory performance in predicting successful weaning from prolonged tracheostomy ventilation.

Methods

Prospective, observational study in 130 prolonged mechanically ventilated, tracheotomized patients in a specialized weaning center. Predictive weaning outcome ability of arterial blood gas analyses and indices derived from calculated MP at beginning and end of weaning was determined in terms of area under receiver operating characteristic curve (AUROC) and measures derived from k-fold cross-validation (likelihood ratios, diagnostic odds ratio, F₁ score, and Matthews correlation coefficient [MCC]).

Results

Forty-four (33.8%) patients experienced weaning failure. Absolute MP showed poor discrimination in predicting outcome; whereas specific MP (MP normalized to dynamic lung-thorax compliance, LTC_dyn-MP) had moderate diagnostic accuracy (MCC 0.38; AUROC 0.79, 95%CI [0.71‒0.86], p < 0.001), further improved by correction for corresponding mechanical ventilation P_aCO₂ (termed the power index of the respiratory system [PI_rs]: MCC 0.52; AUROC 0.86 [0.79‒0.92], p < 0.001). Diagnostic performance of MP indices increased over the course of weaning, with maximum accuracy immediately before completion (LTC_dyn-MP: MCC 0.49; AUROC 0.86 [0.78‒0.91], p < 0.001; PI_rs: MCC 0.68; AUROC 0.92 [0.86‒0.96], p < 0.001).

Conclusions

MP normalized to dynamic lung-thorax compliance, a surrogate for applied power per unit of ventilated lung volume, accurately discriminated between low and high risk for weaning failure following prolonged mechanical ventilation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01566-8.

Patient-ventilator asynchrony as a predictor of weaning failure in mechanically ventilated COPD patients

Background

Patient-ventilator asynchrony is a common problem in mechanically ventilated patients. It is associated with adverse effects including increased work of breathing, patient discomfort, increased need for sedation, prolonged mechanical ventilation, weaning difficulties, and weaning failure. The purpose of the present was to describe patient-ventilator asynchrony and its impact on weaning outcomes in mechanically ventilated chronic obstructive pulmonary disease (COPD) patients.

Results

One hundred mechanically ventilated COPD patients were enrolled in this prospective study. Weaning failure (need of NIV or reintubation within 48 h) was noticed in 27 (27%) patients while 73 (73%) patients had successful weaning. Patients with failed weaning had significantly higher asynchrony index (A.I) and ineffective trigger index (ITI) in comparison with those with successful weaning (7.69 ± 3.71, 3.46 ± 2.59 versus 6.27 ± 3.14, 2.47 ± 2.08, respectively; P value< 0.04). Data were expressed as mean ± standard deviation.

Conclusion

High asynchrony index and high ineffective trigger index may be early predictors of weaning failure in mechanically ventilated COPD patients.

Mortality outcomes of patients on chronic mechanical ventilation in different care settings: A systematic review

Objectives

To determine the outcomes of chronically ventilated patients outside the setting of intensive care units.

Design

Systematic review.

Setting and participants

Studies evaluating patients on chronic invasive mechanical ventilation in different care settings.

Methods

A systematic literature search of the PubMed, Embase, Cochrane Library, CINAHL (EBSCOhost), LILACS and Scopus databases from inception to March 27, 2020. Studies reporting mortality outcomes of patients ≥18 years of age on chronic invasive mechanical ventilation in intensive care units and other care settings were eligible for inclusion.

Results

Sixty studies were included in the systematic review. Mortality rates ranged from 13.7% to 77.8% in ICUs (n = 17 studies), 7.8%-51.0% in non-ICUs including step-down units and inpatient wards (n = 26 studies), and 12.0%-91.8% in home or nursing home settings (n = 19 studies). Age was associated with mortality in all care settings. Weaning rates ranged from 10.0% to 78.2% across non-ICU studies. Studies reporting weaning as their primary outcome demonstrated higher success rates in weaning. Home care studies reported low incidences of ventilator failure. None of the studies reported ventilator malfunction as the primary cause of death.

Conclusions and implications

Mortality outcomes across various settings were disparate due to methodological and clinical heterogeneity among studies. However, there is evidence to suggest non-ICU venues of care as a comparable alternative to ICUs for stable, chronically ventilated patients, with the additional benefit of providing specialized weaning programs. By synthesizing the global data on managing chronically ventilated patients in various care settings, this study provides health care systems and providers alternative venue options for the delivery of prolonged ventilatory care in the context of limited ICU resources.

The effects of pressure- versus volume-controlled ventilation on ventilator work of breathing

Background

Measurement of work of breathing (WOB) during mechanical ventilation is essential to assess the status and progress of intensive care patients. Increasing ventilator WOB is known as a risk factor for ventilator-induced lung injury (VILI). In addition, the minimization of WOB is crucial to facilitate the weaning process. Several studies have assessed the effects of varying inspiratory flow waveforms on the patient’s WOB during assisted ventilation, but there are few studies on the different effect of inspiratory flow waveforms on ventilator WOB during controlled ventilation.

Methods

In this paper, we analyze the ventilator WOB, termed mechanical work (MW) for three common inspiratory flow waveforms both in normal subjects and COPD patients. We use Rohrer’s equation for the resistance of the endotracheal tube (ETT) and lung airways. The resistance of pulmonary and chest wall tissue are also considered. Then, the resistive MW required to overcome each component of the respiratory resistance is computed for square and sinusoidal waveforms in volume-controlled ventilation (VCV), and decelerating waveform of flow in pressure-controlled ventilation (PCV).

Results

The results indicate that under the constant I:E ratio, a square flow profile best minimizes the MW both in normal subjects and COPD patients. Furthermore, the large I:E ratio may be used to lower MW. The comparison of results shows that ETT and lung airways have the main contribution to resistive MW in normals and COPDs, respectively.

Conclusion

These findings support that for lowering the MW especially in patients with obstructive lung diseases, flow with square waveforms in VCV, are more favorable than decelerating waveform of flow in PCV. Our analysis suggests the square profile is the best choice from the viewpoint of less MW.

The role of non-invasive ventilation in weaning and decannulating critically ill patients with tracheostomy: A narrative review of the literature

INTRODUCTION

Invasive mechanical ventilation (IMV) is associated with several complications. Placement of a long-term airway (tracheostomy) is also associated with short and long-term risks for patients. Nevertheless, tracheostomies are placed to help reduce the duration of IMV, facilitate weaning and eventually undergo successful decannulation.

METHODS

We performed a narrative review by searching PubMed, Embase and Medline databases to identify relevant citations using the search terms (with synonyms and closely related words) "non-invasive ventilation", "tracheostomy" and "weaning". We identified 13 publications comprising retrospective or prospective studies in which non-invasive ventilation (NIV) was one of the strategies used during weaning from IMV and/or tracheostomy decannulation.

RESULTS

In some studies, patients with tracheostomies represented a subgroup of patients on IMV. Most of the studies involved patients with underlying cardiopulmonary comorbidities and conditions, and primarily involved specialized weaning centres. Not all studies provided data on decannulation, although those which did, report high success rates for weaning and decannulation when using NIV as an adjunct to weaning patient off ventilatory support. However, a significant percentage of patients still needed home NIV after discharge.

CONCLUSIONS

The review supports a potential role for NIV in weaning patients with a tracheostomy either off the ventilator and/or with its decannulation. Additional research is needed to develop weaning protocols and better characterize the role of NIV during weaning.