Mechanical ventilation in Spain, 1998-2016: Changes in the disconnection of mechanical ventilation.

PURPOSE: To evaluate changes in the disconnection of mechanical ventilation in Spain from 1998 to 2016. DESIGN: Post-hoc analysis of four cohort studies. AMBIT: 138 Spanish ICUs. PATIENTS: 2141 patients scheduled extubated. INTERVENTIONS: None. VARIABLES OF INTEREST: Demographics, reason for mechanical ventilation, complications, methods for disconnection, failure on the first attempt at disconnection, duration of weaning, reintubation, post-reintubation tracheotomy, ICU stay and mortality. RESULTS: There was a significant increase (p < 0.001) in the use of gradual reduction of support pressure. The adjusted probability of using the gradual reduction in pressure support versus a spontaneous breathing trial has increased over time, both for the first attempt at disconnection (taking the 1998 study as a reference: odds ratio 0.99 in 2004, 0.57 in 2010 and 2.43 in 2016) and for difficult/prolonged disconnection (taking the 1998 study as a reference: odds ratio 2.29 in 2004, 1.23 in 2010 and 2.54 in 2016). The proportion of patients extubated after the first attempt at disconnection has increased over time. There is a decrease in the ventilation time dedicated to weaning (from 45% in 1998 to 36% in 2016). However, the duration in difficult/prolonged weaning has not decreased (median 3 days in all studies, p = 0.435). CONCLUSIONS: There have been significant changes in the mode of disconnection of mechanical ventilation, with a progressive increase in the use of gradual reduction of pressure support. No relevant changes in outcomes have been observed.

Mechanical ventilation in Spain, 1998-2016: Epidemiology and outcomes. / Ventilación mecánica en España, 1998-2016: epidemiología y desenlaces.

PURPOSE: To evaluate changes in the epidemiology of mechanical ventilation in Spain from 1998 to 2016. DESIGN: A post hoc analysis of four cohort studies was carried out. SETTING: A total of 138 Spanish ICUs. PATIENTS: A sample of 4293 patients requiring invasive mechanical ventilation for more than 12h or noninvasive ventilation for more than 1h. INTERVENTIONS: None. VARIABLES OF INTEREST: Demographic variables, reason for mechanical ventilation, variables related to ventilatory support (ventilation mode, tidal volume, PEEP, airway pressures), complications during mechanical ventilation, duration of mechanical ventilation, ICU stay and ICU mortality. RESULTS: There was an increase in severity (SAPSII: 43 points in 1998 vs. 47 points in 2016), changes in the reason for mechanical ventilation (decrease in chronic obstructive pulmonary disease and acute respiratory failure secondary to trauma, and increase in neurological disease and post-cardiac arrest). There was an increase in noninvasive mechanical ventilation as the first mode of ventilatory support (p<0.001). Volume control ventilation was the most commonly used mode, with increased support pressure and pressure-regulated volume-controlled ventilation. A decrease in tidal volume was observed (9ml/kg actual b.w. in 1998 and 6.6ml/kg in 2016; p<0.001) as well as an increase in PEEP (3cmH2O in 1998 and 6cmH2O in 2016; p<0.001). In-ICU mortality decreased (34% in 1998 and 27% in 2016; p<0.001), without geographical variability (median OR 1.43; p=0.258). CONCLUSIONS: A significant decrease in mortality was observed in patients ventilated in Spanish ICUs. These changes in mortality could be related to modifications in ventilation strategy to minimize ventilator-induced lung injury.

Mechanical ventilation in Spain, 1998-2016: changes in the disconnection of mechanical ventilation. / Ventilación mecánica en España, 1998-2016: cambios en la desconexión de la ventilación mecánica.

PURPOSE: To evaluate changes in the disconnection of mechanical ventilation in Spain from 1998 to 2016. DESIGN: Post-hoc analysis of four cohort studies. AMBIT: 138 Spanish ICUs. PATIENTS: 2141 patients scheduled extubated. INTERVENTIONS: None. VARIABLES OF INTEREST: Demographics, reason for mechanical ventilation, complications, methods for disconnection, failure on the first attempt at disconnection, duration of weaning, reintubation, post-reintubation tracheotomy, ICU stay and mortality. RESULTS: There was a significant increase (p<0.001) in the use of gradual reduction of support pressure. The adjusted probability of using the gradual reduction in pressure support versus a spontaneous breathing trial has increased over time, both for the first attempt at disconnection (taking the 1998 study as a reference: odds ratio 0.99 in 2004, 0.57 in 2010 and 2.43 in 2016) and for difficult/prolonged disconnection (taking the 1998 study as a reference: odds ratio 2.29 in 2004, 1.23 in 2010 and 2.54 in 2016). The proportion of patients extubated after the first attempt at disconnection has increased over time. There is a decrease in the ventilation time dedicated to weaning (from 45% in 1998 to 36% in 2016). However, the duration in difficult/prolonged weaning has not decreased (median 3 days in all studies, p=0.435). CONCLUSIONS: There have been significant changes in the mode of disconnection of mechanical ventilation, with a progressive increase in the use of gradual reduction of pressure support. No relevant changes in outcomes have been observed.

Low dose anti-inflammatory radiotherapy for the treatment of pneumonia by covid-19: A proposal for a multi-centric prospective trial.

BACKGROUND: COVID-19 is a highly contagious viral infection with high morbidity that is draining health resources. The biggest complication is pneumonia, which has a serious inflammatory component, with no standardized treatment. Low-dose radiation therapy (LD-RT) is non-invasive and has anti-inflammatory effects that can interfere with the inflammatory cascade, thus reducing the severity of associated cytokine release and might be useful in the treatment of respiratory complications caused by COVID-19. STUDY DESIGN AND METHODS: This multicentric prospective clinical trial seeks to evaluate the efficacy of bilateral lung LD-RT therapy as a treatment for interstitial pneumonia in patients with COVID-19 for improving respiratory function.This prospective study will have 2 phases: I) an exploratory phase enrolling 10 patients, which will assess the feasibility and efficacy of low-dose lung irradiation, evaluated according to an increase in the PaO2/FiO2 ratio of at least 20% at 48-72 h with respect to the pre-irradiation value. If a minimum efficiency of 30% of the patients is not achieved, the study will not be continued. II) Non-randomized comparative phase in two groups: a control group, which will only receive pharmacological treatment, and an experimental arm with pharmacological treatment and LD-RT. It will include 96 patients, the allocation will be 1: 2, that is, 32 in the control arm and 64 in the experimental arm. The primary end-point will be the efficacy of LD-RT in patients with COVID-19 pneumonia according to an improvement in PaO2/FiO2. Secondary objectives will include the safety of bilateral lung LD-RT, an improvement in the radiology image, overall mortality rates at 15 and 30 days after irradiation and characterizing anti-inflammatory mechanisms of LD-RT by measuring the level of expression of adhesion molecules, anti-inflammatory cytokines and oxidative stress mediators.Trial registration: ClinicalTrial.gov NCT-04380818 https://clinicaltrials.gov/ct2/show/NCT04380818?term=RADIOTHERAPY&cond=COVID&draw=2&rank=4.

Approach to patients who fail initial weaning trials.

Most patients who are recovering from respiratory failure are successfully liberated from mechanical ventilation easily and soon after the causative disorders are corrected. Roughly one third of patients, however, are not successful on initial attempts at liberation. Clinicians should define and treat the causes of respiratory failure and use validated methods to initiate weaning and manage patients who fail initial spontaneous breathing trials.

Volume-controlled ventilation and pressure-controlled inverse ratio ventilation: a comparison of their effects in ARDS patients.

Volume-controlled ventilation with positive end-expiratory pressure (PEEP) (CPPV) is the conventional ventilatory approach in adult respiratory distress syndrome (ARDS) patients, but some reports suggest that pressure-controlled ventilation with an inverse inspiratory to expiratory ratio (PCIRV) may improve gas exchange in these patients. We analysed the acute effects on gas exchange, lung mechanics and haemodynamics induced by CPPV and PCIRV in ARDS patients. CPPV and PCIRV were applied randomly in ARDS patients. During CPPV, external PEEP was titrated according to the initial inflection point in the static pressure-volume (P-V) curve of the respiratory system, or it was 10 cmH2O when there was no inflection. During PCIRV, external PEEP was not applied, and inspiratory to expiratory (I/E) ratio was inversed until total PEEP was equal to the inflection point in the P-V curve, or it was 10 cmH2O. Respiratory rate, fractional inspiratory oxygen (FIO2), and tidal volume (VT) were kept constant in both modes. Eight ARDS patients were studied prospectively and admitted to a general Intensive Care Unit (ICU) of a University Hospital. Haemodynamic measurements, airflow (V), airway pressure (Paw) and VT were obtained using standard methods. We did not observe any significant change between CPPV and PCIRV with respect to: arterial oxygen tension (PaO2) 117 +/- 12 vs 107 +/- 15 mmHg (16 +/- 2 vs 14 +/- 2 kPa), arterial carbon dioxide tension (PaCO2) 40 +/- 2 vs 39 +/- 2 mmHg (6 +/- 0.3 vs 5 +/- 0.3 kPa), intrapulmonary shunt function (QS/QT) 36 +/- 3 vs 38 +/- 4%, cardiac output (CO) 7.1 +/- 0.7 vs 7 +/- 0.8 l.min-1, and total PEEP 9.7 +/- 0.6 vs 9 +/- 0.3 cmH2O. Oxygen transport and total respiratory system compliance remained unchanged in both modes. Mean Paw was slightly lower during CPPV (17 +/- 1 cmH2O) than during PCIRV (19 +/- 1 cmH2O). PCIRV does not appear to have clinical advantages over CPPV in terms of gas exchange, haemodynamics, or static lung mechanics when using the same total PEEP and minute ventilation.

Clinical characteristics, respiratory functional parameters, and outcome of a two-hour T-piece trial in patients weaning from mechanical ventilation.

The discrepancy in results from different studies regarding outcome of weaning from mechanical ventilation may be due to several factors such as the differences in patient populations and weaning indexes used. In order to analyze the clinical characteristics and weaning indexes in patients undergoing a 2-h T-piece weaning trial and the relationship between the etiology of acute respiratory failure (ARF) and the outcome of this weaning trial, we prospectively studied 217 patients receiving mechanical ventilation who met standard weaning criteria. Successful weaning occurred in 57.6% (125 of 217) of patients: 13 of 33 (39.4%) patients with chronic obstructive pulmonary disease (COPD), 27 of 46 (58.7%) neurologic patients, and 85 of 138 (61.6%) patients with ARF. Ventilatory support was reinstituted in 31.8% (69 of 217) patients: 20 of 33 (60.6%) of patients with COPD, four of 46 (8.7%) neurologic patients, and 45 of 138 (32.6%) patients with ARF (p < 0.001). Reintubation was required in 23 of 148 (15.5%) patients: 15 of 42 (35.7%) neurologic patients, and eight of 93 (8.6%) patients with ARF, whereas no patient with COPD was reintubated (p < 0.001). Using a discriminant analysis, the following variables were selected as the best predictors of outcome: (1) in the whole population, days of mechanical ventilation before weaning trial (DMV), frequency-to-tidal volume ratio (f/VT), maximal inspiratory pressure (MIP), airway occlusion pressure (P0.1), maximal expiratory pressure (MEP), and vital capacity (VC); (2) in patients with ARF, DMV, P0.1/MIP, MIP, f/VT, and age; (3) in patients with COPD, f/VT, P0.1, P0.1/MIP, MIP, age, and DMV; (4) in neurologic patients, MIP, MEP, and f/VT.P0.1. Using these predictors, 74.6% of the whole population, 76.1% of patients with ARF, 93.9% of patients with COPD, and 73.9% of neurologic patients were accurately classified as weaning successes or failures. The highest rate of reintubation occurred in neurologic patients. In this group, the ability to cough and clear respiratory secretions, objectively reflected by MEP, may help in clinical decision-making.

Effect of spontaneous breathing trial duration on outcome of attempts to discontinue mechanical ventilation. Spanish Lung Failure Collaborative Group.

The duration of spontaneous breathing trials before extubation has been set at 2 h in research studies, but the optimal duration is not known. We conducted a prospective, multicenter study involving 526 ventilator-supported patients considered ready for weaning, to compare clinical outcomes for trials of spontaneous breathing with target durations of 30 and 120 min. Of the 270 and 256 patients in the 30- and 120-min trial groups, respectively, 237 (87.8%) and 216 (84.8%), respectively, completed the trial without distress and were extubated (p = 0.32); 32 (13.5%) and 29 (13.4%), respectively, of these patients required reintubation within 48 h. The percentage of patients who remained extubated for 48 h after a spontaneous breathing trial did not differ in the 30- and 120-min trial groups (75.9% versus 73.0%, respectively, p = 0.43). The 30- and 120-min trial groups had similar within-unit mortality rates (13 and 9%, respectively) and in-hospital mortality rates (19 and 18%, respectively). Reintubation was required in 61 (13.5%) patients, and these patients had a higher mortality (20 of 61, 32.8%) than did patients who tolerated extubation (18 of 392, 4.6%) (p < 0.001). Neither measurements of respiratory frequency, heart rate, systolic blood pressure, and oxygen saturation during the trial, nor other functional measurements before the trial discriminated between patients who required reintubation from those who tolerated extubation. In conclusion, after a first trial of spontaneous breathing, successful extubation was achieved equally effectively with trials targeted to last 30 and 120 min.

Extubation outcome after spontaneous breathing trials with T-tube or pressure support ventilation. The Spanish Lung Failure Collaborative Group.

A 2-h T-tube trial of spontaneous breathing was used in selecting patients ready for extubation and discontinuation of mechanical ventilation. However, some doubt remains as to whether it is the most appropriate method of performing a spontaneous breathing trial. We carried out a prospective, randomized, multicenter study involving patients who had received mechanical ventilation for more than 48 h and who were considered by their physicians to be ready for weaning according to clinical criteria and standard weaning parameters. Patients were randomly assigned to undergo a 2-h trial of spontaneous breathing in one of two ways: with a T-tube system or with pressure support ventilation of 7 cm H2O. If a patient had signs of poor tolerance at any time during the trial, mechanical ventilation was reinstituted. Patients without these features at the end of the trial were extubated. Of the 246 patients assigned to the T-tube group, 192 successfully completed the trial and were extubated; 36 of them required reintubation. Of the 238 patients in the group receiving pressure support ventilation, 205 were extubated and 38 of them required reintubation. The percentage of patients who remained extubated after 48 h was not different between the two groups (63% T-tube, 70% pressure support ventilation, p = 0.14). The percentage of patients falling the trial was significantly higher when the T-tube was used (22 versus 14%, p = 0.03). Clinical evolution during the trial was not different in patients reintubated and successfully extubated. ICU mortality among reintubated patients was significantly higher than in successfully extubated patients (27 versus 2.6%, p < 0.001). Spontaneous breathing trials with pressure support or T-tube are suitable methods for successful discontinuation of ventilator support in patients without problems to resume spontaneous breathing.