Clinical validation of a capnodynamic method for measuring end-expiratory lung volume in critically ill patients.

RATIONALE: End-expiratory lung volume (EELV) is reduced in mechanically ventilated patients, especially in pathologic conditions. The resulting heterogeneous distribution of ventilation increases the risk for ventilation induced lung injury. Clinical measurement of EELV however, remains difficult. OBJECTIVE: Validation of a novel continuous capnodynamic method based on expired carbon dioxide (CO2) kinetics for measuring EELV in mechanically ventilated critically-ill patients. METHODS: Prospective study of mechanically ventilated patients scheduled for a diagnostic computed tomography exploration. Comparisons were made between absolute and corrected EELVCO2 values, the latter accounting for the amount of CO2 dissolved in lung tissue, with the reference EELV measured by computed tomography (EELVCT). Uncorrected and corrected EELVCO2 was compared with total CT volume (density compartments between - 1000 and 0 Hounsfield units (HU) and functional CT volume, including density compartments of - 1000 to - 200HU eliminating regions of increased shunt. We used comparative statistics including correlations and measurement of accuracy and precision by the Bland Altman method. MEASUREMENTS AND MAIN RESULTS: Of the 46 patients included in the final analysis, 25 had a diagnosis of ARDS (24 of which COVID-19). Both EELVCT and EELVCO2 were significantly reduced (39 and 40% respectively) when compared with theoretical values of functional residual capacity (p < 0.0001). Uncorrected EELVCO2 tended to overestimate EELVCT with a correlation r2 0.58; Bias - 285 and limits of agreement (LoA) (+ 513 to - 1083; 95% CI) ml. Agreement improved for the corrected EELVCO2 to a Bias of - 23 and LoA of (+ 763 to - 716; 95% CI) ml. The best agreement of the method was obtained by comparison of corrected EELVCO2 with functional EELVCT with a r2 of 0.59; Bias - 2.75 (+ 755 to - 761; 95% CI) ml. We did not observe major differences in the performance of the method between ARDS (most of them COVID related) and non-ARDS patients. CONCLUSION: In this first validation in critically ill patients, the capnodynamic method provided good estimates of both total and functional EELV. Bias improved after correcting EELVCO2 for extra-alveolar CO2 content when compared with CT estimated volume. If confirmed in further validations EELVCO2 may become an attractive monitoring option for continuously monitor EELV in critically ill mechanically ventilated patients. TRIAL REGISTRATION: clinicaltrials.gov (NCT04045262).

The indication of tracheotomy conditions the predictors of time to decannulation in critical patients.

OBJECTIVE: Variables predicting optimal timing for tracheostomy decannulation remain unknown. We aimed to determine whether classifying patients into two groups according to their indications for tracheostomy could identify variables associated with time to decannulation. DESIGN: A prospective, observational cohort study was carried out. LOCATION: Two medical-surgical ICUs. PATIENTS: We included all patients tracheostomized during ICU stay, excluding patients with do-not-resuscitate orders, tracheostomies for long-term airway control, neuromuscular disease, or neurological damage. Patients were classified into two groups: patients tracheostomized due to prolonged weaning and/or prolonged mechanical ventilation (Group 1), and patients tracheostomized due to low level of consciousness or inability to manage secretions (Group 2). INTERVENTIONS: Patients were weaned and decannulated according to established protocols. MAIN VARIABLES: We recorded the following variables: time to tracheostomy, forced vital capacity, peak flow, suctioning requirements, Glasgow Coma Score (GCS), characteristics of respiratory secretions, and swallowing function. Statistical analyses included Cox-proportional multivariate analysis with time to decannulation as the dependent variable. RESULTS: A total of 227 patients were tracheostomized in the ICUs; of these, 151 were finally included in the study. In the multivariate analysis, time to decannulation in Group 1 was associated with the male gender (HR 1.74 (1.04-2.89), p= 0.03), age>60 years (HR 0.58 (0.36-0.91), p= 0.02), high suctioning frequency (HR 0.81 (0.67-0.97), p= 0.02), low forced vital capacity (HR 0.48 (0.28-0.82), p<0.01), and low peak flow (HR 0.25 (0.14-0.46), p<0.01). In Group 2 time to decannulation was associated to GCS >13 (HR 2.73 (1.51-4.91), p<0.01), high suctioning frequency (HR 0.7 (0.54-0.91), p<0.01), and inadequate swallowing (HR 1.97 (1.11-3.52), p=0.02). CONCLUSION: Variables associated with longer time to decannulation in ICU-tracheostomized patients differ with the indications for tracheostomy.

[Severe thrombocytopenia on admission to the intensive care unit in patients with multiple organ failure]. / Trombocitopenia grave al ingreso en una unidad de cuidados intensivos en pacientes con disfunción multiorgánica.

OBJECTIVE: To evaluate the frequency of severe thrombocytopenia (STCP) (≤ 50,000/µl) in the first 24 hours in patients with multiple organ dysfunction syndrome, and the factors that influence its occurrence. DESIGN: A retrospective, observational study. AREA: Medical-surgical intensive care unit (ICU). Tertiary hospital. PATIENTS: Those with failure of at least two organs, according to SOFA criteria, with the exclusion of neurological and traumatologic critical cases. VARIABLES: Medical history, regular medication, baseline functional status, demographic variables, severity scores in ICU, multiple-organ failure data, course in ICU and main hospital data. RESULTS: A total of 587 patients were included; 6.3% (37 patients) presented with STCP during the first day of admission; 64.6% were men; SOFA 8 (5-10); APACHE II 18 (13-24); APACHE IV 59 (46-73); 32.5% were surgical patients. A total of 79.9% subsequently needed mechanical ventilation, and 71.4% required vasoactive drugs. Overall stay in ICU: 4 (2-10) days, main hospital stay 18 (9-35) days. A total of 29.2% died in the ICU; 11.7% developed STCP during admission to the ICU. Multivariate analysis found the main determining factors in the occurrence of thrombocytopenia on admission to be: history of hospitalization in the last year, albumin and bilirubin levels, and sepsis. CONCLUSION: The prevalence of STCP among critical patients was 6.3%. Its occurrence was associated with albumin and bilirubin levels, sepsis, and with patient admittance in the last year.

[Atrioventricular synchrony in patients with pacemaker with VDD mode pacing. A 14-year descriptive study]. / Sincronía auriculo-ventricular en pacientes portadores de marcapasos con estimulación VDD. Estudio descriptivo de un periodo de 14 años.

OBJECTIVE: To analyze the performance of VDD mode pacing in patients with complete AV block with special attention on maintaining AV synchrony. DESIGN: This is a descriptive, retrospective and observational study of a case series. SETTING: Intensive Medicine Department of a tertiary hospital. PATIENTS: All patients with VDD pacemakers implanted between 1994 and 2008. MAIN MEASUREMENTS: The cause of the rhythm disorder, time of atrioventricular synchrony, cause of its loss, number of pacemaker replacement and reason, age when the first implant was performed, incidence of failure of atrial sensing and atrial fibrillation. We compared patients with atrial fibrillation with the rest who maintained normal atrial activity. RESULTS: A total of 95 patients, 49 (51.6%) males and 46 (48.4%) female with mean age of 77.08+/-8.37 years, were analyzed. The most common symptom was dizziness and presyncope in 43 cases (45.3%), the most common rhythm disorder was the III AV block with wide QRS with 68 cases (71.6%). Average time of AV synchrony was maintained 73.01+/-4.2 months with no significant differences between different causes of synchrony loss. At the end of the study, 56 cases remained in AV synchrony (73.3%). CONCLUSIONS: The preservation time of AV synchrony is high, the most important causes of loss being entry in atrial fibrillation and atrial infrasensing.

[Results of the performance of percutaneous coronary revascularization procedures without the presence of heart surgery]. / Resultados de la realización de procedimientos de revascularización coronarios percutáneos sin la presencia de cirugía cardíaca.

The offer of percutaneous coronary revascularization procedures has extended over a large number of health care sites including those that do not have heart surgery. This phenomenon is related with the favorable results of the coronary angioplasty in the treatment of acute coronary syndrome, reported in the scientific literature, above all after the appearance of the coronary stent and the new antiaggregant drugs. In order to offer the primary angioplasty to the population as a treatment that is more effective than drug revascularization, sites having coronary interventionism without heart surgery and sometimes with low volume of patients per year have proliferated. At present, a review is being made of the convenience of continuing with this tendency and reflection is made on the necessary conditions in the expansion of these percutaneous procedures through the secondary level health care sites. The initial data of this review seem to indicate that the existence of interventionist cardiology laboratories in sites without heart surgery can be defended when a minimum number of procedures per year is guaranteed, the primary angioplasty and rescue one being those that have the best results. However, worse results are obtained in sites not supported by heart surgery when non-primary, non-rescue angioplasties and non-ST elevation acute coronary syndromes are dealt with and above all when there is a small volume of patients per year.