Comparison of continuous ST-segment recovery analysis with methods using static electrocardiograms for noninvasive patency assessment during acute myocardial infarction. Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) 7 Study Group.

Continuous ST-segment recovery analysis and 5 static methods using ST-segment comparison between a pre- and post-treatment electrocardiogram were compared for their ability to predict infarct-related artery patency in 82 patients with acute myocardial infarction who underwent angiography a median of 124 minutes after onset of thrombolytic treatment. Accuracy at the moment of angiography was 85% (95% confidence interval [CI] 77% to 93%) for the continuous method, and 68% (CI 57% to 78%), 78% (CI 69% to 87%), 83% (CI 74% to 91%), 82% (CI 73% to 90%), and 80% (CI 71% to 89%) for the static methods. At the moment of angiography the most accurate static method and the continuous method agreed in patency assessment in 90% of the patients (CI 84% to 97%). Agreement was reduced to 83% (CI 75% to 91%) of patients when a patency assessment was performed earlier at 90 minutes after treatment onset, and was only 77% (CI 68% to 86%), at 60 minutes. Early disagreement was mainly seen when the continuous ST recording showed ST recovery from a delayed peak ST elevation after the pretreatment static electrocardiogram or when dynamic ST changes suggesting cyclic reperfusion occurred. Continuous ST-segment recovery analysis appears to be as accurate as the most accurate static methods. Continuously updated reference points appear to give important additional information when ST recovery follows a delayed peak ST elevation or when re-elevation occurs, suggesting cyclic flow changes. Such findings appear to affect about half of patients with acute myocardial infarction treated with intravenous thrombolysis, particularly early after administration of therapy.

Combined historical and electrocardiographic timing of acute anterior and inferior myocardial infarcts for prediction of reperfusion achievable size limitation.

The historical time of acute symptom onset is not always an accurate indication of the timing of onset of an acute myocardial infarction (AMI). Consideration of electrocardiographic (ECG) timing parameters could supplement historical timing alone as a clinical guide for decisions regarding the use of reperfusion therapy. Three hundred ninety-five patients from 4 trials of thrombolytic therapy conducted in the northwestern United States and western Canada are included in the present study. A total of 316 patients received either streptokinase or tissue plasminogen activator, and 79 received no reperfusion therapy. Historical time of symptom onset was acquired by emergency or cardiology department personnel and recorded on patient report forms. An ECG method for estimating the timing of the AMI, the Anderson-Wilkins (AW) acuteness score, was calculated from the initial standard 12-lead recording by investigators blinded to the knowledge of symptom duration or any other study variables. Tomographic thallium-201 imaging 7 weeks after hospital admission was used to measure final AMI size. The ECG timing method achieved a relation with final AMI size similar to that previously reported for historical timing. The AW acuteness score proved most useful for anterior AMI location when there was a > or = 2 hour delay following symptom onset, but was most useful for the inferior AMI location when there was a < 2 hour delay. Despite a longer delay, patients with high AW acuteness scores had 50% lower final anterior AMI size than those with low scores; and despite a shorter delay, those with low ECG acuteness scores had 50% greater final inferior AMI size than those with high scores. The AW acuteness score combined with the historical estimation of symptom duration should provide a more accurate basis for predicting the potential for limitation of final AMI size than either method alone. These results could potentially provide the basis for developing a new method for noninvasive guidance of clinical decisions regarding administration of reperfusion therapy in the initial evaluation of patients with AMI.

Validating the Sedation-Agitation Scale with the Bispectral Index and Visual Analog Scale in adult ICU patients after cardiac surgery.

OBJECTIVE: To validate the Sedation-Agitation Scale (SAS) with the Visual Analog Scale (VAS) and Bispectral Index (BIS) in adult ICU patients after cardiac surgery. DESIGN: Prospective study comparing blinded evaluations of the SAS, VAS and BIS. SETTING: Forty-two-bed multidisciplinary ICU. PATIENTS AND PARTICIPANTS: Convenience sample of 39 adults after cardiac surgery. MEASUREMENTS AND RESULTS: Bispectral Index 3.2 was continuously recorded using the Aspect A-1000 and evaluators were blinded to this value. The bedside nurse and a trained researcher independently rated wakefulness using a 100 mm VAS upon patient arrival on the ICU, at first awakening, when ventilator weaning was started and after extubation; the researcher also evaluated patients using SAS. Upon arrival on the ICU, the median SAS score was 2 (interquartile range = 1-3), the mean VAS was 26+/-30 and the mean BIS was 70+/-16. Twenty-four patients underwent a trial of weaning from mechanical ventilation with a SAS of 4 (IQR = 4), VAS of 86+/-12 and BIS of 87+/-10. SAS correlated well with VAS performed by one researcher (r = 0.91, p < 0.001) or by 19 different bedside nurses (r = 0.43, p < 0.001) and with BIS 3.2 (r = 0.60, p < 0.001). The correlation between SAS and BIS was reduced in patients with above average electromyogram (EMG) power. As a measure of construct validity, significant differences were noted for the BIS, SAS, VAS and EMG between ICU arrival and extubation (all p < 0.001). CONCLUSIONS: Sedation-Agitation Scale and BIS are valid measures of wakefulness after cardiac surgery, but EMG interference may affect the accuracy of BIS for a small percentage of patients not receiving neuromuscular blockade.

The frequency and cost of patient-initiated device removal in the ICU.

OBJECTIVE: To determine the frequency and pattern with which patients in the intensive care unit (ICU) remove medical devices on their own, and the costs associated with this problem. DESIGN: Prospective observational study. SETTING: Two 10-bed sections of a multidisciplinary ICU in a tertiary care teaching hospital. PATIENTS: Adults admitted to the ICU for longer than 24 hours during October 1998. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were reviewed prospectively for the occurrence of patient-initiated device removal and the responses to those events by health care providers. Associated costs were estimated using hospital databases and Medicare physician reimbursement schedules. Annual cost estimates were calculated using 1997 admission statistics for 1211 adults in an ICU for more than 24 hours. Thirty-six patients were studied for 199 patient-days. Ten patients (28%) removed 42 devices: 88% of these events involved gastrointestinal tubes and vascular catheters. Significant agitation was documented within 2 hours before 74% of the events. Estimated cost associated with device removal was $7606, or $181/event. The estimated annual cost in this 42-bed ICU was more than $250,000. CONCLUSIONS: Patients commonly remove medical devices on their own, and this represents significant consumption of health care resources.

Frequency, severity, and treatment of agitation in young versus elderly patients in the ICU.

STUDY OBJECTIVE: To study the frequency, duration, severity, and treatment of agitation in patients in the intensive care unit (ICU) to determine if the elderly represent a distinct population. DESIGN: Prospective cohort study SETTING: Tertiary care, 10-bed, multidisciplinary ICU. PATIENTS: All patients older than 18 years of age admitted for longer than 24 hours during a 4-month period. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: One hundred thirty patients were studied for 916 patient-days; 63 (48%) were elderly (> 65 yrs). Nurses and physicians described agitated behavior in 92 patients (70.8%) during 534 (58.3%) patient-days, and it was severe or dangerous in 60 patients (46.1%) during 273 (30%) patient-days. There were no age-related differences in frequency, severity, and duration of agitation. Opiates, benzodiazepines, and haloperidol were administered during 72%, 62%, and 29% of agitated patient-days, respectively. Haloperidol was administered more often to elderly patients (p=0.015); otherwise no between-group differences were noted. Daily dosing requirements were less in the elderly for intermittent intravenous lorazepam, haloperidol, and morphine but not for midazolam (p=0.15). When these dosages were corrected for body mass, no statistical differences between young and old were found. CONCLUSION: In the ICU, the elderly are not a distinct population for agitation.

Who to report to the coroner? A survey of intensive care unit directors and Her Majesty's Coroners in England and Wales.

We performed a postal survey to assess the ability of intensive care unit directors and Her Majesty's Coroners to recognise deaths that should be reported to the local coroner. The survey questionnaire consisted of 12 hypothetical case scenarios. Coroners were significantly better at identifying reportable deaths than intensive care unit directors (median correct recognition scores of 11 (interquartile range 9.25-11) vs. 8 (interquartile range 7-10), respectively, p < 0.01). Deaths associated with an accident, medical treatments, industrial disease, neglect and substance abuse were significantly under-reported by intensive care unit directors (p < 0.01). Results show that significant numbers of deaths on intensive care units in England and Wales may not be being referred for further investigation, and that wide variation in local coroners' practices exists. Improvements in postgraduate medicolegal education about deaths reportable to a coroner are required. National regulations need to be more detailed and standardised so that regional variation is eliminated.

T wave amplitudes in normal populations. Variation with ECG lead, sex, and age.

Consideration of increased T wave amplitude (tall T waves), either alone or in association with other electrocardiographic (ECG) parameters, may be beneficial for the early detection of acute transmural ischemia, and quantification of the increase might be used in quantifying the ischemic area. The primary purpose of this study was to quantify normal T wave amplitude limits according to ECG lead, sex, and age. One thousand nine hundred thirty-five subjects in two normal populations were analyzed, and the 98th percentile of the positive T wave amplitude for each ECG lead (including -aVR) was considered the upper limit of normal. Normal T wave amplitude was two times greater in the precordial than in the limb leads, and it was approximately 25% greater in men than in women in all leads. There was approximately a 10% decrease in normal T wave amplitude between 18-39- and 40-59-year-old patients and a 15% decrease between 40-59- and 60-79-year-old patients. The upper limit of normal T wave amplitudes identified in this study confirm those developed by Lepeschkin for use as means for each lead when age and sex are not considered. These limits might be incorporated into both normograms and automated ECG analysis systems to determine the presence or absence of tall T waves in patients presenting with symptoms of acute transmural ischemia.

Admission prediction of expected final myocardial infarct size using weighted ST-segment, Q wave, and T wave measurements.

Formulas for predicting final acute myocardial infarction (MI) size from ST-segment deviation on an initial electrocardiogram were proposed by Aldrich et al. for anterior and inferior infarct locations. This study of 529 patients who did not receive thrombolytic therapy was performed to determine the effectiveness of the Aldrich formulas for predicting final QRS MI size; to propose new formulas for predicting final MI size using ST-segment deviation, Q wave, and T wave information in a development population of 322 patients; and to evaluate the new formulas in a randomly selected population of 207 patients. The Aldrich formulas achieved correlations with final infarct size of r = .40 for anterior and r = .43 for inferior MI locations in the present population which are weaker than those previously reported. Formulas that consider electrocardiographic parameters in addition to ST-segment deviation were proposed for both anterior and inferior final MI size. In the test set of 207 patients, these models explained 16.9% and 15.2% of the variation in final MI size for anterior and inferior locations respectively. They may prove useful in assessing the extent of myocardial salvage where interventions are to be tested.