Márcio Manozzo Boniatti

Is hyperchloremia associated with mortality in critically ill patients? A prospective cohort study.

PURPOSE The aim of the study was to determine if acid-base variables are associated with hospital mortality. MATERIALS AND METHODS This prospective cohort study took place in a university-affiliated hospital intensive care unit (ICU). One hundred seventy-five patients admitted to the ICU during the period of February to May 2007 were included in the study. We recorded clinical data and acid-base variables from all patients at ICU admission. A logistic regression model was constructed using Sepsis-related Organ Failure Assessment (SOFA) score, age, and the acid-base variables. RESULTS Individually, none of the variables appear to be good predictors of hospital mortality. However, using the multivariate stepwise logistic regression, we had a model with good discrimination containing SOFA score, age, chloride, and albumin (area under receiver operating characteristic curve, 0.80; 95% confidence interval, 0.73-0.87). CONCLUSIONS Hypoalbuminemia and hyperchloremia were associated with mortality. This result involving chloride is something new and should be tested in future studies.

Prognostic value of the calling criteria in patients receiving a medical emergency team review

AIM To describe the reasons for medical emergency team (MET) activation, and to verify the association of the MET score with 30-day mortality. METHODS This retrospective observational study took place in a 794-bed university-affiliated hospital. The population included all adult admissions reviewed by the MET during the period between January 2007 and June 2008. MET score was defined as the sum of each of the physiological triggers, and score zero was considered the calls made due to concern about the patient, without any physiological alteration. RESULTS During the period of the study, 1051 calls were generated for 901 patients. Respiratory distress and hypotension accounted for most of MET calls. The triggers that showed an independent association with mortality were threatened airway, systolic blood pressure <90 mmHg, decrease in Glasgow Coma Scale score > or =2 points and respiratory frequency >36 breaths/min. Logistic regression analysis revealed MET score, age, medical patient, documented do not resuscitate orders and MET decision to transfer to the intensive care unit to be significant predictors of 30-day mortality. CONCLUSIONS MET score presents a strong association with 30-day mortality in patients seen on the ward.

The reality of patients requiring prolonged mechanical ventilation: a multicenter study

Objetivo: Na ultima decada ocorreu um aumento no numero de pacientes que necessitam manutencao de venti- lacao mecânica prolongada, resultando no surgimento de uma grande popula- cao de pacientes cronicos criticamen- te enfermos. Este estudo estabeleceu a incidencia de ventilacao mecânica pro- longada em quatro unidades de terapia intensiva e relatou as diferentes caracte- risticas, desfechos hospitalares e impacto nos custos e servicos de pacientes com ventilacao mecânica prolongada (depen- dencia de ventilacao mecânica por 21 dias ou mais) em comparacao a pacien- tes sem ventilacao mecânica prolongada (dependencia de ventilacao mecânica in- ferior a 21 dias).Objective The number of patients who require prolonged mechanical ventilation increased during the last decade, which generated a large population of chronically ill patients. This study established the incidence of prolonged mechanical ventilation in four intensive care units and reported different characteristics, hospital outcomes, and the impact of costs and services of prolonged mechanical ventilation patients (mechanical ventilation dependency ≥ 21 days) compared with non-prolonged mechanical ventilation patients (mechanical ventilation dependency < 21 days). Methods This study was a multicenter cohort study of all patients who were admitted to four intensive care units. The main outcome measures were length of stay in the intensive care unit, hospital, complications during intensive care unit stay, and intensive care unit and hospital mortality. Results There were 5,287 admissions to the intensive care units during study period. Some of these patients (41.5%) needed ventilatory support (n = 2,197), and 218 of the patients met criteria for prolonged mechanical ventilation (9.9%). Some complications developed during intensive care unit stay, such as muscle weakness, pressure ulcers, bacterial nosocomial sepsis, candidemia, pulmonary embolism, and hyperactive delirium, were associated with a significantly higher risk of prolonged mechanical ventilation. Prolonged mechanical ventilation patients had a significant increase in intensive care unit mortality (absolute difference = 14.2%, p < 0.001) and hospital mortality (absolute difference = 19.1%, p < 0.001). The prolonged mechanical ventilation group spent more days in the hospital after intensive care unit discharge (26.9 ± 29.3 versus 10.3 ± 20.4 days, p < 0.001) with higher costs. Conclusion The classification of chronically critically ill patients according to the definition of prolonged mechanical ventilation adopted by our study (mechanical ventilation dependency ≥ 21 days) identified patients with a high risk for complications during intensive care unit stay, longer intensive care unit and hospital stays, high death rates, and higher costs.

Inhalation injury after exposure to indoor fire and smoke: the Brazilian disaster experience

OBJECTIVE To describe the pre-hospital, emergency department, and intensive care unit (ICU) care and prognosis of patients with inhalation injury after exposure to indoor fire and smoke. MATERIALS AND METHODS This is a prospective observational cohort study that includes patients admitted to seven ICUs after a fire disaster. The following data were collected: demographic characteristics; use of fiberoptic bronchoscopy; degree of inhalation injury; percentage of burned body surface area; mechanical ventilation parameters; and subsequent events during ICU stay. Patients were followed to determine the ICU and hospital mortality rates. RESULTS Within 24h of the incident, 68 patients were admitted to seven ICUs. The patients were young and had no comorbidities. Most patients (n=35; 51.5%) only had an inhalation injury. The mean ventilator-free days for patients with an inhalation injury degree of 0 or I was 12.5±8.1 days. For patients with an inhalation injury degree of II or III, the mean ventilator-free days was 9.4±5.8 days (p=0.12). In terms of the length of ICU stay for patients with degrees 0 or I, and patients with degrees II or III, the median was 7.0 days (5.0-8.0 days) and 12.0 days (8.0-23.0 days) (p<0.001), respectively. In addition, patients with a larger percentage of burned surface areas also had a longer ICU stay; however, no association with ventilator-free days was found. The patients with <10% of burned body surface area showed a mean of 9.2±5.4 ventilator-free days. The mean ventilator-free days for patients who had >10% burned body surface area was 11.9±9.5 (p=0.26). The length of ICU stay for the <10% and >10% burned body surface area patients was 7.0 days (5.0-10.0 days) and 23.0 days (11.5-25.5 days) (p<0.001), respectively. CONCLUSIONS We conclude that burn patients with inhalation injuries have different courses of disease, which are mainly determined by the percentage of burned body surface area.

Marcadores inflamatórios e perfusionais como preditores e fatores de risco para readmissão de pacientes gravemente enfermos

Results: The C-reactive protein, central venous oxygen saturation, base deficit, and lactate levels and the SWIFT and SOFA scores did not correlate with the readmission of critically ill patients. Increased age and contact isolation because of multidrug-resistant organisms were identified as risk factors that were independently associated with readmission in this study group. Conclusion: Inflammatory and perfusion parameters were not associated with patient readmission. Increased age and contact isolation because of multidrug-resistant organisms were identified as predictors of readmission to the intensive care unit.

The Reality of Patients Requiring Prolonged Mechanical Ventilation: A Retrospective Multicenter Cohort Study

Context: The number of patients requiring prolonged mechanical ventilation (PMV) has increased over the last decade, generating a large population of chronically ill patients. Objective: To establish the incidence of PMV in four Intensive Care Units (ICUs), and to report different characteristics, hospital outcomes, and the impact of costs and services of PMV patients (mechanical ventilation dependency = 21 days) compared with non-PMV patients (mechanical ventilation dependency < 21 days). Design, Setting, and Patients: A retrospective multicenter cohort study, including all patients admitted to four ICUs. Main Outcome Measures: Length of stay in the ICU, hospital, complications during ICU stay, and ICU and hospital mortality. Results: During study period, there were 5,287 admission episodes to the ICUs. Forty-one point five percent of these patients needed ventilatory support (n=2,197), and 218 met criteria for PMV (9.9%). Some complications developed during ICU stay, such as muscle weakness, pressure ulcers, bacterial nosocomial sepsis, candidemia, pulmonary embolism, and hyperactive delirium, were associated with a significantly higher risk of PMV. PMV patients had a significant increase in ICU mortality (absolute difference=14.2%, p<0.001), and in hospital mortality (absolute difference=19.1%, p<0.001); PMV group spent more days in the hospital after ICU discharge (26.9 ± 29.3 vs. 10.3 ± 20.4, p<0.001) and with higher costs. Conclusions: the classification of chronically critically ill patients according to the definition of PMV adopted by our study (mechanical ventilation dependency =21 days) identified patients with high risk for complications during ICU stay, high ICU and hospital stay, high death rates, as well as higher costs.

Advances in performance, more benefits... the perspectives of rapid response teams.

Rapid response teams (RRT) emerged in 1990 with the goals of improving the identification of ward patients with clinical deterioration and offering, based on this identification, early intervention.(1-3) An RRT is activated according to previously defined triggers, traditionally vital signs, by themselves or as part of aggregated scores, other clinical changes, such as seizures, or even by a subjective criterion of concern about a patient. Once activated, the RRT evaluates the patient within five minutes, preferably, and defines the required procedures, such as fluid administration, antibiotic initiation, ventilatory support, and transfer to the intensive care unit (ICU). The presence of RRT in hospitals has been strongly suggested by organizations such as the Joint Commission and Institute for Healthcare Improvement.(4,5) This suggestion is based on the possible benefit of providing early critical care to patients with deterioration, combined with evidence from “before and after” studies of cardiac arrest reduction.(1,6) With the wide spread of rapid response systems, a constant increase has been observed in publications related to multiple elements of this model.(1) Recently, other potential benefits, in addition to strategies to improve the performance of RRT, have been described. In this edition of the Revista Brasileira de Terapia Intensiva, Mezzaroba et al. present a retrospective cohort study on the implementation of RRTs led by intensivists in university hospitals.(7) Although the RRT performance in this study has been restricted to 12 daytime hours, the initiative has produced the following quality criteria:(8) the “dose” delivered by the RRT was 102 calls per 1,000 admissions in the first year, with a median of two minutes for the arrival of the RRT at the bedside. Even with the decline in the number of calls in the following years, the “dose” was still well above the recommended minimum rate (25 per 1,000).(9) Although the authors highlight the risk factors for hospital mortality, the performance characteristics of the RRT itself are the most relevant data. The subjective criteria of concern about the patient was the main trigger used to activate the RRT, reinforcing its importance in increasing the low sensitivity of objective criteria.(10,11) In addition, the RRT had, among its responsibilities, to visit critical patients who remained in the ward daily. This is consistent with broader RRT activity, which has been suggested to include, for example, proactive visits and follow-up of patients discharged from the ICU.(12,13) The retrospective design and the decrease in the number of calls are possible limitations of this study. The authors describe that the decrease in calls may be due to the implementation of daily visits; however, it is very likely that professional and/or cultural barriers have contributed. Marcio Manozzo Boniatti1

Reply to Dubin

Sir: We would like to thank Dr. Dubin and colleagues for their comments about our recent article [1]. However, we disagree with most of their statements. First of all, the greater sensitivity of Stewart’s method using the strong ion difference (SID) compared to the use of base excess (BE) cannot be explained by the use of different cutoff points. We agree that to diagnose metabolic acidosis, we would need a 5 mmol/l reduction in BE and only 2 mmol/l in SID, which means a greater sensitivity for the last criterion. However, if this were the explanation, it would be enough to change the cutoff point of BE, and all cases diagnosed using the SID criterion would also be identified using the BE criterion. But this is not so. In our cases, of the 34 patients with BE between -1.9 and ?1.9 mmol/l, most (n = 27, 79.4%) still had SID \38 mmol/l (data not shown). And we go even further. The best performance is not limited to identifying cases that have not been diagnosed by the traditional evaluation; there is also a better determination of the magnitude of the disorder. In the case of patient 2 of our article [1], if we were to reduce the cutoff point of BE to -2 mmol/l, we would identify metabolic acidosis in this patient. However, the reduction of the base buffer (BB) would be only 3.2 mmol/l; using the criterion of SID the reduction is at least 11 mmol/l. This is a large difference. Independently of the cause of the disorder, the aggressiveness of management will be different. Another point raised by Dr. Dubin and colleagues concerns the diagnosis of the examples mentioned in our article [1]. These are not patients with primary respiratory alkalosis with SID reduction by renal compensation. Dr. Dubin and colleagues repeat the evaluation used in their article [2]. They evaluate the physiological response to the acid–base disorders by calculating the expected values for PCO2 or HCO3 in the cases of a metabolic or respiratory primary change, respectively. We do not agree with this methodology. The interpretation of the physiological responses is very complex in critically ill patients. These responses are derived from studies with animals or healthy patients. Diagnosing a new disorder, only when the response is different from the expected value sounds simplistic to us. We prefer the methodology already described by Dr. Fencl [3], in which the disorders are explained by a change in at least one of the three independent variables [PCO2, SID and total weak acid concentration (Atot)]. In our two examples, one patient was admitted due to septic shock and the other during the postoperative period for neurosurgery, and both were on mechanical ventilation. Again, these are not patients with respiratory alkalosis as a primary disorder. They are patients with primary metabolic acidosis (low SID) with compensatory hypocapnia determined by the parameters of mechanical ventilation. Dr. Dubin and colleagues stated that: ‘‘compensatory responses never overcorrect the pH.’’ This does not apply when the response is determined by our interventions. We agree that there is a good relationship between BE and SID, and this is not new information. A change in BE is essentially the same as the change in SID only if Atot remains unaltered. This is extremely uncommon in critically ill patients. For this reason, we firmly believe that we should use the criterion of SID at the bedside in intensive care units. BE is good; SID is better. We can improve our diagnostic capacity, not only identifying more cases, but also being more precise in determining the magnitude of the disorder.