Respiratory Subsets in Patients with Moderate to Severe Acute Respiratory Distress Syndrome for Early Prediction of Death.

Introduction: In patients with acute respiratory distress syndrome (ARDS), the PaO2/FiO2 ratio at the time of ARDS diagnosis is weakly associated with mortality. We hypothesized that setting a PaO2/FiO2 threshold in 150 mm Hg at 24 h from moderate/severe ARDS diagnosis would improve predictions of death in the intensive care unit (ICU). Methods: We conducted an ancillary study in 1303 patients with moderate to severe ARDS managed with lung-protective ventilation enrolled consecutively in four prospective multicenter cohorts in a network of ICUs. The first three cohorts were pooled (n = 1000) as a testing cohort; the fourth cohort (n = 303) served as a confirmatory cohort. Based on the thresholds for PaO2/FiO2 (150 mm Hg) and positive end-expiratory pressure (PEEP) (10 cm H2O), the patients were classified into four possible subsets at baseline and at 24 h using a standardized PEEP-FiO2 approach: (I) PaO2/FiO2 ≥ 150 at PEEP < 10, (II) PaO2/FiO2 ≥ 150 at PEEP ≥ 10, (III) PaO2/FiO2 < 150 at PEEP < 10, and (IV) PaO2/FiO2 < 150 at PEEP ≥ 10. Primary outcome was death in the ICU. Results: ICU mortalities were similar in the testing and confirmatory cohorts (375/1000, 37.5% vs. 112/303, 37.0%, respectively). At baseline, most patients from the testing cohort (n = 792/1000, 79.2%) had a PaO2/FiO2 < 150, with similar mortality among the four subsets (p = 0.23). When assessed at 24 h, ICU mortality increased with an advance in the subset: 17.9%, 22.8%, 40.0%, and 49.3% (p < 0.0001). The findings were replicated in the confirmatory cohort (p < 0.0001). However, independent of the PEEP levels, patients with PaO2/FiO2 < 150 at 24 h followed a distinct 30-day ICU survival compared with patients with PaO2/FiO2 ≥ 150 (hazard ratio 2.8, 95% CI 2.2−3.5, p < 0.0001). Conclusions: Subsets based on PaO2/FiO2 thresholds of 150 mm Hg assessed after 24 h of moderate/severe ARDS diagnosis are clinically relevant for establishing prognosis, and are helpful for selecting adjunctive therapies for hypoxemia and for enrolling patients into therapeutic trials.

The PANDORA Study: Prevalence and Outcome of Acute Hypoxemic Respiratory Failure in the Pre-COVID-19 Era.

OBJECTIVES: To establish the epidemiological characteristics, ventilator management, and outcomes in patients with acute hypoxemic respiratory failure (AHRF), with or without acute respiratory distress syndrome (ARDS), in the era of lung-protective mechanical ventilation (MV). DESIGN: A 6-month prospective, epidemiological, observational study. SETTING: A network of 22 multidisciplinary ICUs in Spain. PATIENTS: Consecutive mechanically ventilated patients with AHRF (defined as Pao2/Fio2 ≤ 300 mm Hg on positive end-expiratory pressure [PEEP] ≥ 5 cm H2O and Fio2 ≥ 0.3) and followed-up until hospital discharge. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Primary outcomes were prevalence of AHRF and ICU mortality. Secondary outcomes included prevalence of ARDS, ventilatory management, and use of adjunctive therapies. During the study period, 9,803 patients were admitted: 4,456 (45.5%) received MV, 1,271 (13%) met AHRF criteria (1,241 were included into the study: 333 [26.8%] met Berlin ARDS criteria and 908 [73.2%] did not). At baseline, tidal volume was 6.9 ± 1.1 mL/kg predicted body weight, PEEP 8.4 ± 3.1 cm H2O, Fio2 0.63 ± 0.22, and plateau pressure 21.5 ± 5.4 cm H2O. ARDS patients received higher Fio2 and PEEP than non-ARDS (0.75 ± 0.22 vs 0.59 ± 0.20 cm H2O and 10.3 ± 3.4 vs 7.7 ± 2.6 cm H2O, respectively [p < 0.0001]). Adjunctive therapies were rarely used in non-ARDS patients. Patients without ARDS had higher ventilator-free days than ARDS (12.2 ± 11.6 vs 9.3 ± 9.7 d; p < 0.001). All-cause ICU mortality was similar in AHRF with or without ARDS (34.8% [95% CI, 29.7-40.2] vs 35.5% [95% CI, 32.3-38.7]; p = 0.837). CONCLUSIONS: AHRF without ARDS is a very common syndrome in the ICU with a high mortality that requires specific studies into its epidemiology and ventilatory management. We found that the prevalence of ARDS was much lower than reported in recent observational studies.

A Prognostic Enrichment Strategy for Selection of Patients With Acute Respiratory Distress Syndrome in Clinical Trials.

OBJECTIVES: Incomplete or ambiguous evidence for identifying high-risk patients with acute respiratory distress syndrome for enrollment into randomized controlled trials has come at the cost of an unreasonable number of negative trials. We examined a set of selected variables early in acute respiratory distress syndrome to determine accurate prognostic predictors for selecting high-risk patients for randomized controlled trials. DESIGN: A training and testing study using a secondary analysis of data from four prospective, multicenter, observational studies. SETTING: A network of multidisciplinary ICUs. PATIENTS: We studied 1,200 patients with moderate-to-severe acute respiratory distress syndrome managed with lung-protective ventilation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We evaluated different thresholds for patient's age, PaO2/FIO2, plateau pressure, and number of extrapulmonary organ failures to predict ICU outcome at 24 hours of acute respiratory distress syndrome diagnosis. We generated 1,000 random scenarios as training (n = 900, 75% of population) and testing (n = 300, 25% of population) datasets and averaged the logistic coefficients for each scenario. Thresholds for age (< 50, 50-70, > 70 yr), PaO2/FIO2 (≤ 100, 101-150, > 150 mm Hg), plateau pressure (< 29, 29-30, > 30 cm H2O), and number of extrapulmonary organ failure (< 2, 2, > 2) stratified accurately acute respiratory distress syndrome patients into categories of risk. The model that included all four variables proved best to identify patients with the highest or lowest risk of death (area under the receiver operating characteristic curve, 0.86; 95% CI, 0.84-0.88). Decision tree analyses confirmed the accuracy and robustness of this enrichment model. CONCLUSIONS: Combined thresholds for patient's age, PaO2/FIO2, plateau pressure, and extrapulmonary organ failure provides prognostic enrichment accuracy for stratifying and selecting acute respiratory distress syndrome patients for randomized controlled trials.

A risk tertiles model for predicting mortality in patients with acute respiratory distress syndrome: age, plateau pressure, and P(aO(2))/F(IO(2)) at ARDS onset can predict mortality.

BACKGROUND: Predicting mortality has become a necessary step for selecting patients for clinical trials and defining outcomes. We examined whether stratification by tertiles of respiratory and ventilatory variables at the onset of acute respiratory distress syndrome (ARDS) identifies patients with different risks of death in the intensive care unit. METHODS: We performed a secondary analysis of data from 220 patients included in 2 multicenter prospective independent trials of ARDS patients mechanically ventilated with a lung-protective strategy. Using demographic, pulmonary, and ventilation data collected at ARDS onset, we derived and validated a simple prediction model based on a population-based stratification of variable values into low, middle, and high tertiles. The derivation cohort included 170 patients (all from one trial) and the validation cohort included 50 patients (all from a second trial). RESULTS: Tertile distribution for age, plateau airway pressure (P(plat)), and P(aO(2))/F(IO(2)) at ARDS onset identified subgroups with different mortalities, particularly for the highest-risk tertiles: age (> 62 years), P(plat) (> 29 cm H(2)O), and P(aO(2))/F(IO(2)) (< 112 mm Hg). Risk was defined by the number of coexisting high-risk tertiles: patients with no high-risk tertiles had a mortality of 12%, whereas patients with 3 high-risk tertiles had 90% mortality (P < .001). CONCLUSIONS: A prediction model based on tertiles of patient age, P(plat), and P(aO(2))/F(IO(2)) at the time the patient meets ARDS criteria identifies patients with the lowest and highest risk of intensive care unit death.

Anesthesia and analgesia protocol during therapeutic hypothermia after cardiac arrest: a systematic review.

BACKGROUND: Present practice guidelines recommend sedative-analgesic and neuromuscular blocking administration during therapeutic hypothermia in comatose patients after cardiac arrest. However, none suggests the best administration protocol. In this study, we evaluated intensivists' preferences regarding administration. METHODS: A systematic literature review was conducted to identify clinical studies published between 1997 and July 2009. Selected articles had to meet the following criteria: use of hypothermia to improve neurologic outcome after cardiac arrest, and specific mention of the sedative protocol used. We checked drugs and dose used, the reason for their administration, and the specific type of neurologic and neuromuscular monitoring used. RESULTS: We identified 44 studies reporting protocols used in 68 intensive care units (ICUs) from various countries. Midazolam, the sedative used most often, was used in 39 ICUs at doses between 5 mg/h and 0.3 mg/kg/h. Propofol was used in 13 ICUs at doses up to 6 mg/kg/h. Eighteen ICUs (26%) did not report using any analgesic. Fentanyl was the analgesic used the most, in 33 ICUs, at doses between 0.5 and 10 microg/kg/h, followed by morphine in 4 ICUs. Neuromuscular blocking drugs were routinely used to prevent shivering in 54 ICUs and to treat shivering in 8; in 1 ICU, their use was discouraged. Pancuronium was used the most, in 24 ICUs, followed by cisatracurium in 14. Four ICUs used neuromuscular blocking drug administration guided by train-of-four monitoring and 3 ICUs used continuous monitoring of cerebral activity. CONCLUSIONS: There is great variability in the protocols used for anesthesia and analgesia during therapeutic hypothermia. Very often, the drug and the dose used do not seem the most appropriate. Only 3 ICUs routinely used electroencephalographic monitoring during paralysis. It is necessary to reach a consensus on how to treat this critical care population.

[Can heart donation exclusion factors be overcome?]. / Análisis de los motivos de exclusión de la donación cardiaca. 'Causas superables?

INTRODUCTION AND OBJECTIVES: A shortage of heart donors is limiting the expansion of transplant programs. Our aims were to investigate the impact of different heart donation exclusion factors and to examine ways of increasing the donor pool. PATIENTS AND METHOD: We carried out a retrospective descriptive study of individuals donating organs at a university hospital over a ten-year period. Males under 50 years of age and females under 55 years were regarded as potential heart donors. We recorded the etiology of brain death, initial heart donation exclusion factors, and later reasons for rejection. RESULTS: We studied 130 organ donors, 69 of whom were regarded as potential heart donors. Thirty-nine actually became heart donors (i.e., 30% of all donors and 56.5% of those of a suitable age). Thirteen were excluded because of a history of heart disease; the majority died from ischemic or hemorrhagic stroke, excluding rupture of an aneurysm or arteriovenous malformation (P< .005). Another 11 donors were excluded because of ventricular dysfunction, which was probably secondary to brain death in 10 patients. Ventricular dysfunction accounted for 30% of cases of heart donation exclusion. A comparison of donor subgroups showed that the incidence of ventricular dysfunction did not vary according to the cause of brain death. Among 27 elderly potential donors, 70% died of stroke and 85% had a diagnosis of, or risk factors for, heart disease. CONCLUSIONS: Ventricular dysfunction accounted for 30% of cases of heart donation exclusion. Prevention or reversal of this condition could increase the heart donor pool.

Análisis de los motivos de exclusión de la donación cardiaca. ¿Causas superables? / Can heart donation exclusion factors be overcome?

Introducción y objetivos. La escasez de donantes cardiacos limita la expansión de los programas de trasplante. Nuestro objetivo es valorar el impacto de las diferentes causas de exclusión de la donación cardiaca y analizar potenciales aspectos superables. Pacientes y método. Estudio descriptivo, retrospectivo, en el que se incluye a los donantes de órganos de un hospital durante 10 años. Consideramos como potenciales donantes cardiacos a los varones menores de 50 años y a las mujeres menores de 55 años. Analizamos las causas de muerte encefálica y las razones de exclusión inicial de la donación o su posterior rechazo. Resultados. Evaluamos a 130 donantes, 69 de ellos considerados potenciales donantes cardiacos. En total 39 fueron donantes efectivos de corazón (el 30% de todos los donantes y el 56,5% de los que, por criterios de edad, podrían haber llegado a serlo). Trece donantes fueron excluidos por antecedentes de cardiopatía, la mayoría en el grupo fallecido por accidente cerebrovascular (ACVA), excepto los que tenían rotura de aneurisma o malformación (p < 0,005). Once donantes fueron excluidos por disfunción ventricular, en 10 probablemente secundaria a la muerte encefálica. Esta disfunción ventricular supuso el 30% de los motivos de exclusión de la donación. No hubo diferencias en la incidencia de disfunción ventricular cuando se comparó a los grupos con distintas causas de muerte encefálica. Entre los 27 potenciales donantes de edad avanzada, el 70% falleció por ACVA y en el 85% había un diagnóstico de cardiopatía o presentaba factores de riesgo para tenerla. Conclusiones. La disfunción ventricular supone el 30% de las exclusiones de la donación cardiaca. La prevención o reversión de este fenómeno podría aumentar la reserva de donantes cardiacos

Introduction and objectives. A shortage of heart donors is limiting the expansion of transplant programs. Our aims were to investigate the impact of different heart donation exclusion factors and to examine ways of increasing the donor pool. Patients and method. We carried out a retrospective descriptive study of individuals donating organs at a university hospital over a ten-year period. Males under 50 years of age and females under 55 years were regarded as potential heart donors. We recorded the etiology of brain death, initial heart donation exclusion factors, and later reasons for rejection. Results. We studied 130 organ donors, 69 of whom were regarded as potential heart donors. Thirty-nine actually became heart donors (i.e., 30% of all donors and 56.5% of those of a suitable age). Thirteen were excluded because of a history of heart disease; the majority died from ischemic or hemorrhagic stroke, excluding rupture of an aneurysm or arteriovenous malformation (P<.005). Another 11 donors were excluded because of ventricular dysfunction, which was probably secondary to brain death in 10 patients. Ventricular dysfunction accounted for 30% of cases of heart donation exclusion. A comparison of donor subgroups showed that the incidence of ventricular dysfunction did not vary according to the cause of brain death. Among 27 elderly potential donors, 70% died of stroke and 85% had a diagnosis of, or risk factors for, heart disease. Conclusions. Ventricular dysfunction accounted for 30% of cases of heart donation exclusion. Prevention or reversal of this condition could increase the heart donor pool