RESUMO
OBJECTIVE: To determine factors related to limitations on life support within 48h of intensive care unit (ICU) admission. STUDY DESIGN: Prospective multicenter study. SETTING: Eleven ICUs. PATIENTS: All patients who died and/or had limitations on life support after ICU admission during a four-month period. VARIABLES: Patient characteristics, hospital characteristics, characteristics of limitations on life support. Time-to-first-limitation was classified as early (<48h of admission) or late (≥48h). We performed univariate, multivariate analyses and CHAID (chi-square automatic interaction detection) analysis of variables associated with limitation of life support within 48h of ICU admission. RESULTS: 3335 patients were admitted; 326 (9.8%) had limitations on life support. A total of 344 patients died; 247 (71.8%) had limitations on life support (range among centers, 58.6%-84.2%). The median (p25-p75) time from admission to initial limitation was 2 (0-7) days. CHAID analysis found that the modified Rankin score was the variable most closely related with early limitations. Among patients with Rankin >2, early limitations were implemented in 71.7% (OR=2.5; 95% CI: 1.5-4.4) and lung disease was the variable most strongly associated with early limitations (OR=12.29; 95% CI: 1.63-255.91). Among patients with Rankin ≤2, 48.8% had early limitations; patients admitted after emergency surgery had the highest rate of early limitations (66.7%; OR=2.4; 95% CI: 1.1-5.5). CONCLUSION: Limitations on life support are common, but the practice varies. Quality of life has the greatest impact on decisions to limit life support within 48h of admission.
Assuntos
Cuidados Críticos/normas , Cuidados para Prolongar a Vida/normas , Suspensão de Tratamento , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Admissão do Paciente , Estudos Prospectivos , Fatores de TempoRESUMO
BACKGROUND: The role of venous blood gases as an alternative to arterial blood gases in patients with severe acute heart failure has not been established. OBJECTIVE: To assess the correlation between arterial and peripheral venous blood gases together with pulse-oximetry (SpO2), as well as to estimate arterial values from venous samples in the first hours upon admission of patients with acute cardiogenic pulmonary oedema. METHODS: Simultaneous venous and arterial blood samples were extracted on admission and over the next 1, 2, 3, 4, and 10 hours. SpO2 was also registered at the same intervals. RESULTS: A total of 178 pairs of samples were obtained from 34 consecutive patients with acute cardiogenic pulmonary oedema. Arterial and venous blood gases followed a parallel course in the first hours, showing high correlation rates at all time intervals. Venous samples underestimated pH (mean difference -0.028) and overestimated CO2 (+5.1 mmHg) and bicarbonate (+1 mEq/l). Conversely, SpO2 tended to underestimate SaO2 (mean±SD: 93.1±9.1 vs. 94.2±8.4). Applying simple mathematical formulae based on these differences, arterial values were empirically calculated from venous samples, showing acceptable agreement in the Bland-Altman test. Likewise, a venous pH <7.32, pCO2 >51.3 mmHg, and bicarbonate <22.8 mEq/l could fairly identify arterial acidosis, either respiratory or metabolic, with a test accuracy of 92, 68, and 91%, respectively. CONCLUSIONS: In patients with cardiogenic pulmonary oedema, arterial blood gas disturbances may be estimated from peripheral venous samples. By monitoring SpO2 simultaneously, arterial punctures could often be avoided.