Background: Early prediction of proximal left anterior descending coronary artery (LAD) occlusion is essential from a clinical point of view Hypothesis: To develop an electrocardiogram (ECG) algorithm based on ST-segment deviations to predict the location of occlusion of LAD as a culprit artery. Methods: ECG and angiographic findings were correlated in 100 patients with an ST-segment elevation myocardial infarction (MI) in precordial leads V 1 , V 2 , and V 4 through V 6 . Results: ST-depression ≥2.5 mm in leads III + ventricular fibrillation (VF) presents sensitivity (SE) of 77% and specificity (SP) of 84% for LAD occlusion proximal to the first diagonal artery (D1). ST-segment in III + VF isoelectric or elevated, presents SE of 44% and SP of 100% for LAD occlusion distal to D1. Subsequent analysis of the equation of ST-deviation in VR + V 1 − V 6 <0, allows us to predict occlusion distal to first septal artery (S1) with 100% SP. On the other hand, any ST-depression in III + VF >0.5 mm + of ST-deviation in VR + V 1 − V 6 ≥0 identifies a high-risk group (lower ejection fraction, worse Killip findings, higher peak of CPK and CK-MB, and major adverse cardiac events [MACE]: death, reinfarction, recurrent angina, persistent left ventricular failure, or sustained ventricular arrhythmia during hospitalization). Conclusions: This sequential ECG algorithm based on ST-segment deviations in different leads allowed us to predict the location of occlusion in LAD with good accuracy. Cases with proximal LAD occlusion present the most markers of poor prognosis. We recommend the use of the algorithm in everyday clinical practice.Key words: electrocardiography, coronary angiography, acute myocardial infarction Introduction ST-elevation in precordial leads in patients with acute coronary syndrome (ACS) symptoms indicates ST-segment elevation myocardial infarction (STEMI) involving the area perfused by the left anterior descending coronary artery (LAD). 1 -5 This information alone does not predict the extent of the potentially damaged myocardium. It is known that proximal LAD occlusion involves a larger zone of myocardium than distal occlusion and therefore has a worse prognosis. 6,7 Thus, an early prediction of proximal LAD occlusion is important not only from an academic standpoint, but also from a clinical point of view. Changes in ST-segment in different leads of surface ECG can identify patients with proximal or distal LAD occlusion. 8 -20 Nevertheless, we consider it better to have an easy-to-use algorithm based on deviations of ST in 12-lead ECG than to assess the ECG criteria separately. Here we present such an algorithm based on the evaluation of ST changes in 12-lead ECG correlated with angiographic findings.

The accuracy of pulse oximetry for the prediction of oxygen saturation of arterial blood in patients with shock has been hardly studied. This study was undertaken to determine if O2 arterial saturation estimated by the Biox 3700 pulse oximeter (SpO2) with an ear probe could reliably substitute for the measurements of O2 saturation (HbO2) with an IL-282 Co-Oximeter in samples of arterial blood obtained from 24 caucasian patients. All patients were mechanically ventilated and needed vasoactive drugs (dopamine and/or dobutamine). Of 24 patients 13 had shock: cardiogenic (n = 6) and septic (n = 7). The mean difference between HbO2 and SpO2 was 2.49% +/- 4.24, with a 95% confidence interval of 0.7% to 4.3% (p = 0.009). There were clinically important differences between both methods since in 9 of 24 patients (37%) SpO2 values were at least 4% lower or greater than HbO2. This disagreement was also apparent in patients with (6/13, 46%) or without shock (3/11, 27%). To conclude, pulse oximetry is not always a sufficiently reliable method to predict HbO2 in patients with or without shock treated with vasoactive drugs.

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Objective. The purpose of this series was to describe the ultrasonographic perfusion pattern in patients with brain death. Methods. Thirteen patients with different neurologic disorders in whom brain death developed were studied. Transcranial perfusion was analyzed after injection of 2.5 mL of a sulfur hexafluoride ultrasonographic contrast agent. Time-intensity curves were analyzed in predetermined regions of interest. Results. In all patients, analysis of regions of interest showed no boluslike curve progression. This finding implies a complete absence of cerebral perfusion. Conclusions. Patients with brain death studied by ultrasonographic perfusion techniques have a characteristic pattern. Key words: brain death; cerebral perfusion; time-intensity curves; ultrasonographic contrast agent; ultrasonographic perfusion imaging.Received October 26, 2007, he role of transcranial ultrasonography in confirming brain death 1 and reducing the time to transfer patients with brain death to the operating room has been clearly shown.2 A recent report by the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology 3 stated that its sensitivity and specificity in diagnosis of brain death range from 91% to 100% and 97% to 100%, respectively. Transcranial color ultrasonography allows a complete structural and hemodynamic study in neurocritically ill patients. 4 The introduction of ultrasonographic contrast agents (UCAs) permits the most accurate studies 5 and minimally invasive bedside evaluations of cerebral perfusion. 6 Different ultrasonographic perfusion imaging (UPI) techniques to evaluate cerebral perfusion in neurocritically ill patients have been developed. [6][7][8][9][10][11][12][13][14][15] These techniques are based on the use of recently developed UCAs, the effects of which are based on the presence of micro-