Miriam M. Treggiari

BACKGROUND: Assessment of a patient's readiness for removal of the endotracheal tube in the ICU is based on respiratory, airway, and neurological measures. However, nearly 20% of patients require reintubation. We created a prediction model for the need for reintubation, which incorporates variables importantly contributing to extubation failure. METHODS: This was a cohort study of 2,007 endotracheally intubated subjects who required ICU admission at a tertiary care center. Data collection included demographic, hemodynamic, respiratory, and neurological variables preceding extubation. Data were compared between subjects extubated successfully and those who required reintubation, using bivariate logistic regression models, with the binary outcome reintubation and the baseline characteristics as predictors. Multivariable logistic regression analysis with robust variance was used to build the prediction model. RESULTS: Of the 2,007 subjects analyzed, 376 (19%) required reintubation. In the bivariate analysis, admission Simplified Acute Physiology Score II, minute ventilation, breathing frequency, oxygenation, number of prior SBTs, rapid shallow breathing index, airway-secretions suctioning frequency and quantity, heart rate, and diastolic blood pressure differed significantly between the extubation success and failure groups. In the multivariable analysis, higher Simplified Acute Physiology Score II and suctioning frequency were associated with failed extubation. The area under the receiver operating characteristic curve was 0.68 for failure at any time, and 0.71 for failure within 24 hours. However, prior failed SBT, minute ventilation, and diastolic blood pressure were additional independent predictors of failure at any time, whereas oxygenation predicted extubation failure within 24 hours. CONCLUSIONS: A small number of independent variables explains a substantial portion of the variability of extubation failure, and can help identify patients at high risk of needing reintubation. These characteristics should be incorporated in the decision-making process of ICU extubation.

The management of patients with traumatic brain injury has evolved in the last several years, due to the introduction of new, invasive monitoring devices. The ability to monitor parameters other than measurements related to pressures has generated substantial interest. Brain tissue oxygenation monitoring has been consistently shown to provide prognostic information, as indicated by poor prognosis associated with low brain tissue oxygen values. Furthermore, various physiologic manipulations, including increasing the PaO₂, have been associated with an increase in brain tissue oxygenation. Whether brain-oxygenation-guided therapy results in improvement in outcomes is debatable. Retrospective studies suggest benefit, while prospective studies have shown a higher intensity of therapeutic interventions with no outcome differences. Data from high quality randomized trials are necessary to determine if brain-oxygenation-guided therapy is beneficial. An oxygen challenge (transient increase in FIO₂ to 0.6 up to 1.0) to assess the responsiveness of the monitoring and ascertain the presence of technical malfunction is an accepted practice.

Purpose Elevated intracranial pressure (ICP) has been associated with increased mortality in patients with severe traumatic brain injury (TBI). We have examined whether raised ICP is independently associated with mortality, functional status and neuropsychological functioning in adult TBI patients. Methods Data from a randomized trial of 499 participants were secondarily analyzed. The primary endpoints were mortality and a composite measure of functional status and neuropsychological function (memory, speed of information processing, executive function) over a 6-month period. The area under the curve of the ICP profile (average ICP) during the first 48 h of monitoring was the main predictor of interest. Multivariable regression was used to adjust for a priori defined confounders: age, Glasgow Coma Score, Abbreviated Injury Scale–head and hypoxia. Results Of the participants, 365 patients had complete 48-h ICP data. The overall 6-month mortality was 18 %. The adjusted odds ratio of mortality comparing 10-mmHg increases in average ICP was 3.12 (95 % confidence interval 1.79, 5.44; p < 0.01). Overall, higher average ICP was associated with decreased functional status and neuropsychological functioning (p < 0.01). Importantly, among survivors, increasing average ICP was not independently associated with worse performance on neuropsychological testing (p = 0.46). Conclusions Average ICP in the first 48 h of monitoring was an independent predictor of mortality and of a composite endpoint of functional and neuropsychological outcome at the 6-month follow-up in moderate or severe TBI patients. However, there was no association between average ICP and neuropsychological functioning among survivors.

Medical management of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) includes hypertensive, hypervolemic, and hemodilution (“triple-H”) therapy. However, there is little information regarding the indications and guidance used to initiate and adjust triple-H therapy. A 43-item questionnaire was e-mailed to 375 members of the Neurocritical Care Society. Questions were designed to investigate the diagnostic approach to cerebral vasospasm and prophylactic and therapeutic administration of triple-H therapy. Completed surveys were received from 167 respondents (45% response proportion). Eighty-six percent of respondents worked in hospitals with neurointensive care units (NICUs). SAH patients in hospitals with a NICU had longer ICU stay (P = 0.037) and had indwelling central venous catheters for longer (P < 0.01). Centers without dedicated NICUs were more likely to induce prophylactic hypervolemia (P < 0.01). Twenty seven percent of respondents (n = 45) reported using prophylactic hypervolemia in patients with SAH, while 100% reported inducing hypervolemia for severe or symptomatic vasospasm. Twelve percent (n = 20) of respondents reported inducing prophylactic hypertension, while all reported inducing hypertension with severe or symptomatic vasospasm. Half of respondents relied on the mean arterial pressure and half on systolic blood pressure as the clinical parameter for blood pressure titration. The most widely used agents to induce hypertension were phenylephrine (48%) and norepinephrine (39%). There was little variation in the use of hemodilution therapy comparing patients with or without evidence of vasospasm. There are substantial differences in the administration of prophylactic triple-H, but there was high agreement on indication for therapeutic use. There was wide variability in the extent of ICU monitoring, diagnostic approach, physiologic parameters and values used as target of therapy. NICU availability was associated with more intensive monitoring. Lack of evidence and guidelines for triple-H therapy might largely explain these findings.

To investigate if light sedation favorably affects subsequent patient mental health compared with deep sedation. Symptoms of posttraumatic stress disorder are common in patients after they have undergone prolonged mechanical ventilation and are associated with sedation depth. Randomized, open-label, controlled trial. Single tertiary care center. Adult patients requiring mechanical ventilation. Patients were randomized to receive either light (patient awake and cooperative) or deep sedation (patient asleep, awakening upon physical stimulation). Self-reported measures of posttraumatic stress disorder, anxiety, and depression were collected at intensive care unit discharge and 4 wks later. The primary outcomes were symptoms of posttraumatic stress disorder, anxiety, and depression 4 wks after intensive care unit discharge. A total of 137 patients were assigned to either the light (n = 69) or the deep sedation (n = 68) group. Seven patients withdrew consent and one patient was randomized in error, leaving 129 patients (n = 65 in light sedation and n = 64 in deep sedation) available for analysis. At the 4-wk follow-up, patients in the deep sedation group tended to have more posttraumatic stress disorder symptoms (p = .07); the deep sedation group had more trouble remembering the event (37% vs. 14%; p = .02) and more disturbing memories of the intensive care unit (18% vs. 4%; p = .05). Patients in the light sedation group had an average one day less being ventilated and 1.5 fewer days in the intensive care unit. There were no differences between the two groups in the occurrence of anxiety and depression, and also no difference in mortality or in the incidence of adverse events. These data suggest that a strategy of light sedation affords benefits with regard to reduction of intensive care unit stay and duration of ventilation without negatively affecting subsequent patient mental health or patient safety.

To summarize the recent literature of the hemodynamic management of subarachnoid hemorrhage and cerebral vasospasm, also designated as 'triple-H' therapy, and discuss each component of this management approach individually. Following the publication of a review on circulatory volume expansion in the Cochrane Registry database in 2004 and a meta-analysis in 2003, there are no new randomized trials of triple-H therapy to prevent or treat cerebral vasospasm. However, physiological studies have been reported that contribute to the understanding of some of the components of triple-H therapy. There remains a paucity of information regarding the efficacy and safety of triple-H therapy. The complexity in exploring this topic derives not only from the interdependence of the different components of triple-H therapy but also by the limitation in the assessment of hemodynamic variables. However, there is some emerging physiologic data suggesting that normovolemic hypertension may be the component most likely to increase cerebral blood flow after subarachnoid hemorrhage. In contrast, hypervolemic hemodilution is associated with increased complications and might also lower the hemoglobin to excessively low levels.

Introduction: Little is known about the mechanisms through which intensivist physician staffing influences patient outcomes. We aimed to assess the effect of closed-model intensive care on evidence-based ventilatory practice in patients with acute lung injury (ALI). Methods: We conducted a secondary analysis of a prospective population-based cohort of 759 patients with ALI who were alive and ventilated on day three of ALI, and were cared for in 23 intensive care units (ICUs) in King County, Washington. Results: We compared day three tidal volume (V_T) in open versus closed ICUs adjusting for potential patient and ICU confounders. In 13 closed model ICUs, 429 (63%) patients were cared for. Adjusted mean V_T (mL/Kg predicted body weight (PBW) or measured body weight if height not recorded) for patients in closed ICUs was 1.40 mL/Kg PBW (95% confidence interval (CI) = 0.57 to 2.24 mL/Kg PBW) lower than patients in open model ICUs. Patients in closed ICUs were more likely (odds ratio (OR) = 2.23, 95% CI = 1.09 to 4.56) to receive lower V_T (≤ 6.5 mL/Kg PBW) and were less likely (OR = 0.30, 95% CI = 0.17 to 0.55) to receive a potentially injurious V_T (≥ 12 mL/Kg PBW) compared with patients cared for in open ICUs, independent of other covariates. The effect of closed ICUs on hospital mortality was not changed after accounting for delivered V_T. Conclusions: Patients with ALI cared for in closed model ICUs are more likely to receive lower V_T and less likely to receive higher V_T, but there were no other differences in measured processes of care. Moreover, the difference in delivered V_T did not completely account for the improved mortality observed in closed model ICUs.

Introduction: Intensive insulin therapy (IIT) with tight glycemic control may reduce mortality and morbidity in critically ill patients and has been widely adopted in practice throughout the world. However, there is only one randomized controlled trial showing unequivocal benefit to this approach and that study population was dominated by post-cardiac surgery patients. We aimed to determine the association between IIT and mortality in a mixed population of critically ill patients. Methods: We conducted a cohort study comparing three consecutive time periods before and after IIT protocol implementation in a Level 1 trauma center: period I (no protocol); period II, target glucose 80 to 130 mg/dL; and period III, target glucose 80 to 110 mg/dL. Subjects were 10,456 patients admitted to intensive care units (ICUs) between 1 March 2001 and 28 February 2005. The main study endpoints were ICU and hospital mortality, Sequential Organ Failure Assessment score, and occurrence of hypoglycemia. Multivariable regression analysis was used to evaluate mortality and organ dysfunction during periods II and III relative to period I. Results: Insulin administration increased over time (9% period I, 25% period II, and 42% period III). Nonetheless, patients in period III had a tendency toward higher adjusted hospital mortality (odds ratio [OR] 1.15, 95% confidence interval [CI] 0.98, 1.35) than patients in period I. Excess hospital mortality in period III was present primarily in patients with an ICU length of stay of 3 days or less (OR 1.47, 95% CI 1.11, 1.93 There was an approximately fourfold increase in the incidence of hypoglycemia from periods I to III. Conclusion: A policy of IIT in a group of ICUs from a single institution was not associated with a decrease in hospital mortality. These results, combined with the findings from several recent randomized trials, suggest that further study is needed prior to widespread implementation of IIT in critically ill patients.