WEANING FROM MECHANICAL VENTILATION. COMPARISON OF TWO METHODS

Jose R Azevedo, Cecilma M Teixeira, Kivania C Pessoa, Sandra C Maia, Maria M Braga
1999 Critical Care Medicine  
Objectives: In the treatment of acute myocardial infarction (MI), the time delay to achieve reperfusion of the infarction-related artery has been linked to survival rates. Primary or direct angioplasty has been found to be an excellent means of achieving reperfusion in acute ST-elevation MI compared to thrombolytic therapy in randomized trials. However, no mortality benefit of primary angioplasty over thrombolysis was observed in several registries, in which delays in performing primary
more » ... sty were longer. Our objectives were to evaluate the door-to-balloon time (DBT) in our institution and investigate its relationship with clinical and prognostic variables. We divided our patient population into two groups. Group A (GA) included patients with DBT less than 120 min and group B (GB) patients with DBT greater or equal to 120 min. We evaluated several clinical variables, such as left ventricular ejection fraction (LVEF) on their first echocardiogram during hospitalization, admission Killip classification, in-hospital length of stay (LOS) and major cardiovascular events (MACE) during hospitalization and up to 6-month follow-up (in 23 patients). Results: The median DBT was 132 min and the mean was 165 min, with a standard deviation of 137 min for all the cases. We had 32 patients in the GA and 35 patients (52%) in the GB. We observed four in-hospital deaths, all in GB. The mean LVEF was 53.1 ± 9% in GA and 46.1 ± 13% in GB (P = 0.059). Admission Killip class greater than 1 was noted in three patients of each group. The in-hospital LOS was similar for both groups (GA = 8.35 ± 4 and GB = 8.33 ± 4 days; NS). In-hospital events occurred in eight patients of GA (25%) and seven patients of GB (20%; NS). Only five follow-up events occurred during the first 6 months, three events in GA patients and two in GB patients (NS). Conclusion: DBT greater than or equal to 2 h are common and in our population it occurred in more than half of the primary angioplasties. Greater than 2 h DBTs were associated with a trend to larger left ventricular dysfunction early after MI. Monitoring and measures to reduce DBT are crucial for the potential prognosis improvement offered by primary angioplasty and for the broadening of its use in the management of acute MI. Because only a few studies about acute myocardial infarction (AMI) include elderly patients, we compared outcomes of patients aged 70 years or older with AMI who underwent thrombolysis or primary angioplasty treatment. Methods: From April 1995 to June 1999, 64 patients within 12 h of symptom onset and no contraindications for thrombolytic therapy were randomized in two groups. Group I (32 patients, 20 men) submitted to an infusion of 1.5 million units of intravenous streptokinase (SK) and group II (32 patients, 17 men) to primary angioplasty (PA). Primary end-points included incidence of death, reinfarction, stroke, or readmission after 6 months follow up. Baseline characteristics of the two groups did not show significant differences. Results: Clinical results are shown in the Table. The success rate (residual stenosis less than 50% and TIMI 3 flow) in group II was 86%. Group I patients were 1.5 times more likely to have combined end-points (95% CI 0.89-2.40; P = 0.21). Conclusion: These findings suggest that in elderly patients eligible for thrombolytic therapy, primary angioplasty and SK were safe. The two methods of reperfusion were comparable according to these end-points during the follow up. The delay to perform primary angioplasty may be one of the causes of these findings. Table SK (n = 32) PA (n = 32) P Pain onset-presentation (min)* 180 (90/360) 180 (120/291) NS Presentation-treatment (min)* 45 (22/60) 105 (70/175) 0.0002 Reinfarction/stroke/readmission (%) 2/0/5 (22) 6/1/1 (25) NS Death 6 months (%) 12 (37.5) 6 (19) 0.16 Combined end-points (%) 18 (56) 12 (37.5) 0.21 Complications from catheter (%) 5/27 (19) 9/32 (28) 0.54 Treatment (clinic/revasc) 16/16 7/25 0.036 Time of hospital (days)* 8 (2/16) 8 (6/15) NS *Data presented are median (25 th , 75 th centiles). Background: Long distance aeromedical transport of patients post myocardial infarction (MI) occurs with increasing frequency. Despite the benefits of early transport, there are potential risks. Data documenting the frequency of complications are lacking, and guidelines for aeromedical transport post MI are nonexistent. Objective: To determine the safety of long distance aeromedical transport post MI and identify risk factors associated with transport-related complications. Methods: Analysis of data from a retrospective study of long distance aeromedical transports performed by Montreal-based Skyservice Lifeguard transport service. (A manuscript describing this study has been accepted for publication in the journal Aviation, Space, and Environmental Medicine.) For patients transported by Lear Jet air ambulance post MI, potential risk factors examined included age, gender, Killip class, revascularization procedures, and status at time of transportation (days since admission, chest pain free interval, intravenous medications, and oxygen use). Results: A total of 51 patients were transported by air ambulance during the study period. There were no major complications. Minor inflight complications (ie chest pain, desaturation, or hypotension) occurred in 10% of patients and resolved rapidly with onboard medical intervention. Univariate and multiple logistic regression analysis of the potential risk factors will be presented. Conclusion: Long distance aeromedical transport post MI may be safely performed with a low incidence of minor complications that are easily manageable inflight. Delaying transport 48-72 h after resolution of chest pain reduces the incidence of complications. Practice guidelines for long distance air ambulance transport of post-MI patients need to be established. Background: The literature states that age relates to prehospital delay time interval from acute symptom onset to emergency department admission. Several studies indicate that patients of advanced age are more likely to experience delayed reperfusion therapy after hospital presentation. This study aims to assess time to treatment differences between patients under 75 years old and elderly patients. Methods: Prospective study of 116 admissions with ST elevation acute myocardial infarction (STEAMI) who received primary percutaneous transluminal coronary angioplasty (PTCA) treatment for STEAMI in a tertiary hospital over a 2-year period (March 1999-March 2001. Prehospital delay time (∆T1) was measured, as well as time between hospital presentation and establishment of reperfusion therapy (∆T2) and time between initial puncture and balloon insufflation in a cardiac catheteriza-tion laboratory (∆T3). Epi-info 6.0 software was used to perform statistical analyses. Results: Among a cohort of 116 patients, 70.6% were men; the mean age was 64.8 ± 13 years and 24.2% were over 75 years old. Mean ∆T1 in patients under 75 years old was 218.3 min and in patients over 75 years old was 212.8 min (P = 0.6). Mean ∆T2 in younger patient was 52.1 min and in advanced-age patients was 54.1 min (P = 0.6). Mean ∆T3 in patients under 75 years old was 25.5 min and in elderly was 20.8 min (P = 0.5). Conclusion: Prehospital delay time interval was similar between elderly patients and patients under 75 years. Time to establishment reperfusion therapy and time to treatment with primary PTCA was not different among these patients. The more rapid treatment of appropriate elderly patient with STEAMI probably reduces mortality rates. P5 Comparison among bilevel noninvasive mechanical ventilation, continuous positive airway pressure and oxygen in the treatment of cardiogenic acute pulmonary edema M Objective: To compare the efficacy of bilevel noninvasive ventilation (NIV), continuous positive airway pressure (CPAP) and oxygen (O 2 ) to prevent orotracheal intubation (OI) in cardiogenic acute pulmonary edema (CAPE). Methods: In a prospective study, 51 patients (21 male) with CAPE were randomized into three groups of treatment, 6 min after the arrival at the Emergency Unit. Cardiac and respiratory rates, arterial blood pressure and the peripheral oxygen saturation were determined at later randomization moment, 10, 30, 60 min later. Arterial blood samples were collected at the 0, 30, 60 min. Oxygen was applied by face mask with inspiratory fraction (FiO 2 ) of 50%; CPAP and NIV were applied by face mask using BiPAP ST/D 30 ® with FiO 2 of 50% and initial expiratory pressure or initial CPAP of 10 cmH 2 O and initial inspiratory pressure of 16 cmH 2 O, both titrated according to necessity. Results: OI was significantly lower in the group with expiratory pressure support (NIV 1/17 plus CPAP 2/17, total of three intubations in 34 cases) when compared to O 2 group (5/15; P < 0.05). Conclusion: NIV decreased cardiac and respiratory work more rapidly than CPAP and O 2 . Our data suggest that CPAP and NIV are effective in preventing OI in CAPE. Introduction: Propranolol plasma levels and pharmacokinetics (PK) may be altered by cardiopulmonary bypass (CPB). Propranolol kinetic disposition was investigated in patients submitted to myocardial revascularization with mild hypothermic cardiopulmonary bypass (HCPB). Methods: Fifteen patients receiving propranolol pre-(30-120 mg/day) and postoperatively (5-10 mg/day) were evaluated. Propranolol plasma levels were measured before, during and after surgery using high-performance liquid chromatography. PK modelling based on one compartment open model was applied to data obtained after drug administration (propranolol, tablets) 1 day before surgery and at the first postoperative day. Results: Plasma curve decay represents logarithmic transformation of plasma concentrations before, during and after surgery, presented in the Figure. Pre-and postoperative PK modelling showed a prolongation of biological half-life (t 1/2 β) from 3.2 to 10.2 h (P < 0.01), increases of volume of distribution (Vd/F) from 3.5 to 7.7 l/kg (P ≤ 0.05) and reduction of plasma clearance from 15.8 to 9.1 ml/min.kg (P ≤ 0.05). Discussion: Plasma levels indicate propranolol mobilization, probably due to stress and surgical trauma, since the beginning up to the end of hypothermic cardiopulmonary bypass. The influence of HCPB on pharmacokinetics of propranolol was demonstrated by the three times prolongation of t 1/2 β and Vd/F increased by two times. Additionally, plasma levels increase could be justified by plasma clearance reduction. Conclusion: An accumulation of propranolol might be expected in patients submitted to cardiac surgery with hypothermic cardiopulmonary bypass and lower doses of this drug could be required during the postoperative period. P7 Prognostic value of treadmill stress testing in patients admitted to the emergency room with chest pain R Macaciel, ET Mesquita, R Bassan, R Gamarski, M Scofano, R Vivacqua, S Serra, M Miranda, A Campos, on behalf of Chest Pain Methods: A total of 1060 consecutive patients were evaluated in our Chest Pain Unit using an algorithm that determines the pretest probability of acute myocardial infarction (AMI) or unstable angina (UA) based on chest pain characteristics and admission ECG. Patients with unclear diagnosis were submitted to a systematic strategy of serial ECG and CKMB determinations (0-3-6-9 h). TST was indicated for those in whom AMI or high-risk UA was ruled out. Of the 677 eligible patients 268 (40%) underwent TST (150 within 12 h post-admission) and constitute the study sample that was followed for 1 year (age 51.8 ± 12.1 years, males 70%). Results : TST was positive for myocardial ischemia in 22% of 82 patients initially classified as intermediate probability of AMI/UA, and in 9% of 186 patients classified as low probability (P = 0.004). Cardiac events (death, AMI, UA, revascularization) occurred in 20.6% of 34 patients with positive TST, 0.5% of 191 patients with negative TST and 7% of 43 patients with nondiagnostic TST (submaximal heart rate not achieved; P = 0.0000). Diagnostic accuracy of a positive or nondiagnostic TST for cardiac events: sensitivity 91%, specificity 74%, positive predictive value 13%, and negative predictive value 99%. Likelihood ratio of a positive or nondiagnostic TST was 3.5 and a negative TST was 0.1. Multivariate logistic regression analysis disclosed a positive or nondiagnostic TST as the strongest predictor of cardiac events (OR 19; P = 0.0006) followed by ischemic ST or T changes on the admission ECG (OR 5.7; P = 0.04). Conclusion: Patients with chest pain and unclear diagnosis on admission in whom AMI or high-risk UA were ruled out can be safely and accurately risk stratified by immediate TST. Patients with negative TST can be safely discharged, but those with a positive or nondiagnostic TST need further evaluation due to an elevated rate of cardiac events. P8 A prospective analysis of complications related to the use of glycoprotein IIb/IIIa inhibitors in acute coronary syndromes RM Rocha, CT Mesquita, MCFS Kanto, FS Lugão, AL Cascardo, PS Lira, FOD Rangel, R Esporcatte Hospital Pró-Cardíaco/Coronary Care Unit, Rio de Janeiro, Brazil Background: Glycoprotein IIb/IIIa inhibitors (GPI) are potent antiplatelet agents, with promising results in the treatment of acute coronary syndromes, independently of reperfusion strategies, but with a concerning hemorrhagic profile. Objectives: To analyze an initial experience with the use of abciximab and tirofiban associated to percutaneous coronary interventions (PCI) and their effect on morbidity and mortality, and the relationship with technical, demographic and therapeutic variables. Materials and method: We studied 70 patients (65 abciximab and five tirofiban). Forty-seven men (mean age 62.7 ± 12.9 years) and 23 women (68.8 ± 9.7 years; P = 0.049) were analyzed according to diagnosis, risk factors, hemoglobin and platelet count, bleeding, duration of sheath maintenance and mortality. Results: Diagnoses were acute myocardial infarction (AMI; 42 patients), unstable angina/non-Q-wave AMI (27 patients) and stable angina (1 patient), with seven deaths with a higher mean age (77.4 ± 4.0 versus 63.6 ± 12.3; P < 0.001). We observed strong correlations between mortality and mean hemoglobin levels (P < 0.00001) and mean platelet count (P = 0.013) after PCI. There were 25 hematomas that correlated with longer time of sheath maintenance (P = 0.009). Other bleeding complications were retroperitoneal hematoma (two patients), hematuria (one), pseudoaneurysm (one), oral bleeding (three), hematemesis (two), hemoptysis (two) and hemopericardium (two). Patients who died had ≥2 vessels disease, left ventricle dysfunction, five patients used intra-aortic balloon counterpulsation and six received hemotransfusion. Conclusion: Higher morbidity correlated with increased time of sheath maintenance and higher mortality correlated with hemoglobin and platelet depletion, although this could be due to more bleedings induced by GPI or due to the severity of clinical presentation. Background: C-reactive protein (CRP) has been consistently correlated with cardiovascular events in patient with unstable angina (Biasucci LM et al: Circulation 1999, 99:855-860) and even in healthy individuals. Objective: To analyze the relationship between CRP levels in patients hospitalized due to unstable angina and major adverse cardiac events during a 2-year follow up. Background: Therapeutic approach of non-ST-elevation acute coronary syndrome with glycoprotein IIb/IIIa inhibitors and early coronary angiography (CA) with immediate angioplasty (ACTP), when feasible, has been proposed as a very effective strategy. Objectives: To review demographic data, risk factors, myocardial necrosis markers, C-reactive protein, clinical stabilization with therapy and in-hospital outcome of patients admitted due to unstable angina (UA) or non-Q-wave acute myocardial infarction (nQwAMI). Materials and method: Retrospective analysis was conducted of 43 consecutive patients, 70% of whom were male, mean age 65 ± 13 years, 54% with UA and 46% with nQwAMI. Student's t test and Kruskal-Wallis (KW) tests were used. Results: There was a higher prevalence of UA among men (63%) and of nQwAMI among women (69%; P = 0.05). Braunwald's class IIIB2 was recognized in 86% of the UA group. From the nQwAMI group, 38% were Killip class >1. There were no differences in risk factors, except for the presence of hyperlipidemia (UA 74% versus nQwAMI 38%; P = 0.02). Major interventions are summarized in the Table. Abciximab was used in 15% of patients (UA 66%, nQwAMI 34%). In-hospital outcomes are as follows: mean length of stay, UA 6 ± 5 days, nQwAMI 7 ± 7 days. Of UA patients 13% evolved to AMI. Two deaths occurred (one UA patient and one nQwAMI patient). Median CKMB mass and cardiac troponin were higher in nQwAMI group (10 versus 1.5 and 0.9 versus 0.5, respectively, and both P < 0.001 KW). No difference in C-reactive protein was detected. Conclusion: Aggressive therapy for non-ST-elevation acute coronary syndromes combining abciximab, early angiography and angioplasty with stents resulted in a favorable in-hospital outcome in high-risk patients, with a short length of stay. P11 Features and markers of mortality of hospital patients that use intra-aortic balloon pump AD Background: Intra-Aortic Balloon Pump (IABP) use has been proposed in cardiogenic shock, but cannot improve mortality alone. Preoperative criteria use of IABP can improve outcome and cost in heart surgical patients. Objective: Description and analysis of demographic, clinical, surgical features of surviving and nonsurviving IABP patients. Background: Some pre-and perioperative factors have been associated with a high incidence of AAF in cardiac surgery postop-erative period. Advanced age, longer surgery time, mitral valve surgery and stopping β-blockade have been described. Objective: To evaluate some pre-and perioperative factors in order to identify those patients with higher probability for postoperative AAF. Patients and method: A total of 227 adult patients consecutively admitted in postoperative period were prospectively followed. Clinical and surgical variables were collected and then compared between patients who developed AAF in postoperative period and those who did not. Statistical techniques were Student's t test and Fischer test. Results: The mean age in the two groups were significantly different (69.9 years in AAF patients and 62.6 years in non-AAF patients; P < 0.01). The AHA/ACC mortality and stroke indexes were higher in AAF patients (P < 0.01 and P < 0.001, respectively). Water retention on the first postoperative day was higher in AAF patients (P < 0.01). Euroscore and Cleveland scale were higher in AAF group (P < 0.001 for both indexes). Left atrial size, body mass index, AHC/ACC mediastinitis scale, Goldman index, surgery time, extracorporeal circulation time, aortic clamping time, peroperative water intake, diabetes, chronic obstructive pulmonary disease, left ventricular function, MODS and SOFA indexes were not statistically different in the two groups. AAF incidence was higher in mitral valve postoperative period when compared to post-revascularization period, but it has not met statistical significance. Conclusion: Advanced age, AHA/ACC mortality and stroke indexes, Euroscore and Cleveland scale, and water retention on the first postoperative day were shown to be predictors for AAF in cardiac postoperative period. As few patients have undergone mitral valve surgery, it was not possible to detect statistical difference in AAF incidence between these patients and those who have undergone myocardial revascularization. P16 The electrocardiogram as a predictor of right ventricular dysfunction in patients with pulmonary embolism A Volschan, M Knibel, PCP Souza, ET Mesquita, J Pantoja, E Cantarino, on behalf of the EMEP Investigators Introduction: Right ventricular dysfunction (RVD) is considered to indicate poor prognosis in patients with pulmonary embolism (PE). The electrocardiogram (ECG) is a low-cost, widely avaible method that may show changes associated with right ventricular strain secondary to PE. Objectives: To evaluate the prevalence of ECG changes in patients with PE and its importance as a diagnostic tool in the diagnosis of RVD. Patients and method: Data were collected from a cohort of 202 patients (84 men) enrolled in a multicenter prospective registry study of PE. The mean age was 70.9 ± 13.8 years. Patients were admitted to hospital between January 1998 and January 2001. The diagnosis of PE was confirmed if patients fulfilled at least one of the following criteria: (1) pulmonary artery thrombus visualization by pulmonary arteriography, helicoidal angiotomography, magnetic resonance or echocardiography; (2) high probability pulmonary scintigraphy; and (3) venous duplex scan with thrombus visualization and clinical signs and symptoms of PE. The ECG and transthoracic echocardiogram (TTE) were performed in 190 patients. RVD was established by TTE subjective analysis of the right ventricle contractive function. Abnormal ECG was considered to be indicative of right bundle branch block, S 1 Q 3 T 3 pattern, negative T wave from V1 to V4, or right AQRS axis deviation. Results: ECG was abnormal in 33% of patients and TTE analysis showed RVD in 38%. In this latter group of patients 49% presented with at least one ECG change. At least one ECG change was found in 23% of patients without RVD (P < 0.0001). The accuracy of ECG for the diagnosis of RVD was: sensitivity 49%, specificity 77%, positive predictive value 57% and negative predictive value 71%. The likelihood ratio of a positive test was 2.1 and of a negative test was 0.6. Conclusion: When transthoracic echocardiography is not available, ECG may be useful to exclude right ventricular dysfunction in patients with PE. Introduction: Arterial hypotension is considered a poor prognostic factor in patients with pulmonary embolism (PE), and has been correlated with right ventricle dysfunction (RVD). In case of haemodynamic instability, thrombolytic treatment is frequently indicated. Objective: To evaluate the relation between arterial hypotension and RVD in patients with PE. Patients and method: Data were collected from a cohort of 202 patients (84 men) enrolled in a multicenter prospective registry study of PE. The mean age was 70.9 ± 13.8 years. Patients were admitted to hospitals between January 1998 and January 2001. The diagnosis of PE was confirmed if patients fulfilled at least one of the following criteria: (1) pulmonary artery thrombus visualization by pulmonary arteriography, helicoidal angiotomography, magnetic resonance or echocardiography; (2) high probability pulmonary scintigraphy; and (3) venous duplex scan with thrombus visualization and clinical signs and symptoms of PE. Arterial hypotension was considered if systolic arterial blood pressure was below 90 mmHg, at admission. The transthoracic echocardiogram (TTE) were performed in 193 patients and the RVD was established by subjective analysis of right ventricle function. Results: Arterial hypotension was present in 40 (21%) and the TTE showed RVD in 73 (38%). Arterial hypotension was detected in 21 (29%) patients in RVD group versus 19 (16%) patients in the group without RVD (P = 0.03). The diagnostic accuracy of arterial hypotension regarding RVD was measured as follows: sensitivity 29% and specificity 84%, with a positive predictive value of 52.5% and negative predictive value of 66%. The likelihood ratio of positive test was 1.82 and the likelihood ratio of negative test was 0.85. Conclusion: Arterial hypotension is not a good marker of RVD in patients with PE. Purpose: Our objective was to study the cardiovascular function in canines that underwent progressive normovolemic hemodilution using two different solutions. Method: Eleven consecutive adult patients admitted to the Critical Care Unit of Hospital Albert Einstein, São Paulo, Brazil, in acute respiratory failure due to exacerbation of COPD were randomized to receive PSV (n = 5) versus BiPAP ™ (n = 6). Inclusion criteria were a high probability of acute exacerbation of COPD, Introduction: The multiple organ dysfunction syndrome (MODS) is a major cause of mortality in ARDS. However, there are few studies evaluating this relationship using new score systems for MODS. Methods: All patients in the ICU who met American-European Consensus criteria for ARDS [1] between November 1998 and December 2000 were included in the analysis. Criteria for MODS were those proposed by Marshall et al [2] . Age, gender, APACHE II score and outcome were also evaluated. The patients were divided into survivors (SV) and nonsurvivors (NSV). The differences between groups were analyzed with t-test, χ 2 and Mann-Whitney as indicated. Results: There were 975 admissions to the ICU, of whom 64 (6.6%) presented ARDS criteria. The mean age was 35 ± 13 years and 54 ± 16 years (P < 0.001), and the APACHE II was 16.4 ± 3.3 and 20 ± 5.2 (P = 0.02) in SV and NSV, respectively. General mortality was 79% (n = 51), 39% (n = 20) in females and 61% (n = 31) in males (P = 0.066). The results of the MODS in SV and NSV are shown in the Table. Conclusion: The severity of MODS measured by a specific score is associated with increased mortality in ARDS. Advanced age, male gender and individual dysfunction of renal and hepatic systems were associated with a poor prognosis. Introduction: The participation of a psychologist in ICU team is a recent event that is becoming frequent in some modern hospitals. This experience demands careful evaluation of patients, families and health care team needs, and the efficiency of the psychological intervention. The aim of this work is to describe clinical and epidemiological data about the patients attended by a psychology service at a general ICU in order to optimize the psychologist's work. Materials and method: This retrospective prevalence study is composed by a sample of 515 patients. The instrument was an electronic case register (MedTrack). Results: The preliminary outcomes, from 10 months analyzed, showed that the psychological consultation was made to 19.5% of the patients during their ICU stay. The mean age of the patients was 62 years (SD = 19 years), and 57% were male. The prevalence of psychotherapy assistance made directly to the patient or family members during the hospital stay was 21%. Seventy-nine per cent were the first evaluation, short-time intervention such as educational and brief interventions focused on the admission period. The prevalences of diagnosis were as follows: neoplasic disease (17%), cardiac system (17%), respiratory system (16%), trauma (13%), neurological system (10%) and others (27%).
doi:10.1097/00003246-199912001-00277 fatcat:dqw7tfrjnvasvjjg6l5yy4xryq