Ankle Radiograph Utilization after Learning a Decision Rule: A 12-month Follow-up

Objective: To test whether the reduction in ankle radiograph ordering was sustained during a 12-month period after a formal trial to introduce the Ottawa ankle rules
Methods: A before-after clinical trial of ankle radiograph ordering practice was performed in a university-based ED. All 1,884 (947 "during intervention," 937 "postintervention") adults seen with acute ankle injuries during 2 12-month trial periods were evaluated. The behavioral intervention was the teaching of the Ottawa ankle rules and feedback of compliance with the rules during the intervention period. No further education about the ankle rules or feedback regarding compliance occurred during the postintervention year. Physicians were unaware of any postintervention surveillance. The primary outcome was the proportion of eligible patients referred for an ankle radiograph during the intervention and postintervention periods.
Results: During the intervention period (January 1-December 31, 1993), the proportion of patients who received an ankle radiograph [609 x-rayed of 947 patients seen (64.3%; 95% Cl 61.2–67.4%)] did not differ from the proportion who received an x-ray in the postintervention period (January 1-December 31, 1994) [583 x-rayed of 937 patients seen (62.2%; 95% Cl 59.1–65.3%), p = 0.65, power > 0.80 to detect a 10% increase in the radiograph ordering rate]. There was also no difference in the radiograph ordering rate in the first 3 months of the postintervention period compared with the last 3 months of the postintervention period (68.8% vs 64.7%, respectively, p > 0.30).
Conclusions: Compliance with the Ottawa ankle rules was sustained during a 12-month postintervention surveillance period when physicians did not know they were being observed. Physicians will continue to use a simple clinical guideline once it has been learned.     

A Population-based Study of Fatal and Nonfatal Firearm-related Injuries

Objective: To determine population-based firearm-related morbidity and mortality for Allegheny County, PA (population = 1.3 million), for the year 1994.
Methods: Fatalities were identified from a review of death certificates. To identify nonfatal cases, an active surveillance was conducted at all 24 acute care EDs in the county. The ED surveillance used 2 existing sources of case identification from each hospital to minimize undercount.
Results: Firearms were the leading cause of injury death to county residents, accounting for 155 deaths. The crude mortality rate from firearms was 11.7/100,000. Black males aged 15–19 years were most at risk for a firearm fatality (293/100,000). There were 514 nonfatal firearm injuries, producing a case fatality rate of 23%. The highest age-specific rate for nonfatal firearm-related injuries treated in the county EDs was observed for black males aged 15–19 years (2,245/100,000), which is 58 times higher than the firearm-related injury rate for the entire county population (38.7/100,000).
Conclusion: Firearm-related injury and death are a significant public health problem in Allegheny County. Although the crude mortality rate from firearms in the county is lower than the reported national rate, the observed rate for nonfatal injuries in the black youth of this community is the highest firearm injury incidence rate ever reported. Local surveillance of firearm-related injuries, including nonfatal events, is needed to more accurately demonstrate the magnitude of this problem.     

A Truncated E-code System for Injury Surveillance in the Emergency Department: Description and Clinometric Testing

Objectives: ED injury surveillance requires accurate information about mechanism. This study explored the clinometric properties of an E-code system specifically designed to track ED injuries.
Methods: All patients assessed in the ED had cause-of-injury information documented using a truncated E-code system. Patient records were hand-searched to determine coding compliance. A selection of 98 charts (50 injury/48 noninjury) were coded by 7 physicians, 2 nurses, and 2 nosologists. Agreements (interrater and intrarater) on the diagnosis of trauma and exact E-codes were determined (using kappa; κ).
Results: E-coding compliance was high (overall 90%: 95% CI: 85–93%), and accuracy of injury classification was 99%. Compared with an expert's coding, agreement on injury classification was excellent for physicians (κ = 0.91; 95% CI: 0.80–1.0), nurses (κ = 0.88; 95% CI: 0.75–1.0), and nosologists (κ = 0.92; 95% CI: 0.81–1.0). Agreement was substantial for the exact E-codes between physicians (κ = 0.77; 95% CI: 0.60- 0.94) and nurses (κ = 0.72; 95% CI: 0.54–0.90). Recode reliability was also excellent for physicians (κ = 0.88; 95% CI: 0.75–1.0) and nurses (κ = 0.96; 95% CI: 0.88–1.0).
Conclusions: Injury coding using a truncated E-code system can provide valid and reliable data from the ED. Differences between nurses, physicians, and nosologists in the ability to accurately code using this system were minimal, thus eliminating the need for additional staff and resources.     

Guns and Knives in New Mexico: Patterns of Penetrating Trauma, 1978–1993

Objective: To identify patterns of nonfatal and fatal penetrating trauma among children and adults in New Mexico using ED and medical examiner data.
Methods: The authors retrospectively sampled in 5-year intervals all victims of penetrating trauma who presented to either the state Level-1 trauma center or the state medical examiner from a 16-year period (1978–1993). Rates of nonfatal and fatal firearm and stabbing injury were compared for children and adults.
Results: Rates of nonfatal injury were similar (firearm, 34.3 per 100,000 person-years; stabbing, 35.1). However, rates of fatal injury were significantly different (firearm, 21.9; stabbing, 2.7; relative risk: 8.2; 95% confidence interval: 5.4, 12.5). From 1978 to 1993, nonfatal injury rates increased for children (p = 0.0043) and adults (p < 0.0001), while fatal penetrating injury remained constant. The increase in nonfatal injury in children resulted from increased firearm injury rates. In adults, both stabbing and firearm nonfatal injury rates increased.
Conclusions: Nonfatal injury data suggest that nonfatal violence has increased; fatal injury data suggest that violent death rates have remained constant. Injury patterns vary by age, mechanism of trauma, and data source. These results suggest that ED and medical examiner data differ and that both are needed to guide injury prevention programs.     

Clostridium difficile surveillance: harnessing new technologies to control transmission

Clostridium difficile surveillance allows outbreaks of cases clustered in time and space to be identified and further transmission prevented. Traditionally, manual detection of groups of cases diagnosed in the same ward or hospital, often followed by retrospective reference laboratory genotyping, has been used to identify outbreaks. However, integrated healthcare databases offer the prospect of automated real-time outbreak detection based on statistically robust methods, and accounting for contacts between cases, including those distant to the ward of diagnosis. Complementary to this, rapid benchtop whole genome sequencing, and other highly discriminatory genotyping, has the potential to distinguish which cases are part of an outbreak with high precision and in clinically relevant timescales. These new technologies are likely to shape future surveillance.     

Detection of Electrolyte Abnormalities in Children Presenting to the Emergency Department: A Multicenter, Prospective Analysis

Objective : To prospectively derive high-yield criteria for the detection of clinically significant electrolyte abnormalities (CSEAs) in children presenting to the ED.
Methods : A prospective, multicenter, observational study was performed at the EDs of 2 urban teaching hospitals, a university medical center, and a children's hospital with a combined census of >275,000 patient visits/year (100,000 visits for children <13 years old). All children <13 years old who had electrolyte panels obtained were eligible for analysis. A data form containing potential predictor variables for a CSEA was completed by the clinician prior to receipt of electrolyte results. A CSEA was any abnormal electrolyte value that 1) stimulated constructive assessment of the patient's condition (monitoring, reevaluation of nonspurious laboratory values, or admission), 2) led to further diagnostic studies, 3) led to a new diagnosis, or 4) affected therapy, χ² recursive partitioning was used to derive a decision rule for ordering electrolytes.
Results : Of 715 eligible patient visits, 488 (68%) electrolyte panels contained a laboratory abnormality, with 182 (25%) CSEAs. A decision rule requiring 1 of 6 clinical criteria was 100% sensitive (95% CI 98–100%) and 24% specific (95% CI 21–28%) in detecting CSEAs with positive and negative predictive values of 31% (95% CI 28–34%) and 100% (95% CI 97–100%), respectively. If these criteria had been used to screen patients for whom electrolyte panels were ordered, 128 patients (18%) would not have had electrolyte panels obtained and no CSEAs would have been missed.
Conclusion : A set of clinical criteria was derived that may be useful for limiting electrolyte panels ordering in children. This criterion set requires prospective validation in a separate patient population.     

A Decision Rule for Predicting Bacterial Meningitis in Children with Cerebrospinal Fluid Pleocytosis When Gram Stain Is Negative or Unavailable

Objectives:  Among children with cerebrospinal fluid (CSF) pleocytosis, the task of separating aseptic from bacterial meningitis is hampered when the CSF Gram stain result is unavailable, delayed, or negative. In this study, the authors derive and validate a clinical decision rule for use in this setting.
Methods:  This was a review of peripheral blood and CSF test results from 78 children (<19 years) presenting to Children's Hospital Columbus from 1998 to 2002. For those with a CSF leukocyte count of >7/μL, a rule was created for separating bacterial from viral meningitis that was based on routine laboratory tests, but excluded Gram stain. The rule was validated in 158 subjects seen at the same site (Columbus, 2002–2004) and in 871 subjects selected from a separate site (Boston, 1993–1999).
Results:  One point each (maximum, 6 points) was assigned for leukocytes >597/μL, neutrophils >74%, glucose <38 mg/dL, and protein >97 mg/dL in CSF and for leukocytes >17,000/mL and bands to neutrophils >11% in peripheral blood. Areas under receiver-operator-characteristic curves (AROCs) for the resultant score were 0.98 for the derivation set and 0.90 and 0.97, respectively, for validation sets from Columbus and Boston. Sensitivity and specificity pairs for the Boston data set were 100 and 44%, respectively, at a score of 0 and 97 and 81% at a score of 1. Likelihood ratios (LRs) increased from 0 at a score of 0 to 40 at a score of ≥4.
Conclusions:  Among children with CSF pleocytosis, a prediction score based on common tests of CSF and peripheral blood and intended for children with unavailable, negative, or delayed CSF Gram stain results has value for diagnosing bacterial meningitis.     

The effect of high nursing surveillance on hospital cost

PURPOSE: The purpose of this study was to determine the cost of one nursing treatment, surveillance, for older, hospitalized adults at risk for falling. DESIGN: An observational study using information from data repositories at one Midwestern tertiary hospital. The inclusion criteria included patients age>60 years, admitted to the hospital between July 1, 1998 and June 31, 2002, at risk for falls or received the nursing treatment of fall prevention. METHODS: Data came from clinical and administrative data repositories that included Nursing Interventions Classification (NIC). The nursing treatment of interest was surveillance and total hospital cost associated with surveillance was the dependent variable. Propensity-score analysis and generalized estimating equations (GEE) were used as methods to analyze the data. Independent variables related to patient characteristics, clinical conditions, nurse staffing, medical treatments, pharmaceutical treatments, and other nursing treatments were controlled for statistically. FINDINGS: The total median cost per hospitalization was $9,274 for this sample. The median cost was different (p=0.050) for patients who received high versus low surveillance. High surveillance delivery cost $191 more per hospitalization than did low surveillance delivery. CONCLUSION: Propensity scores were applied to determine the cost of surveillance among hospitalized adults at risk for falls in this observational study. The findings show the effect of high surveillance delivery on total hospital cost compared to low surveillance delivery and provides an example of a useful method of determining cost of nursing care rather than including it in the room rate. More studies are needed to determine the effects of nursing treatments on cost and other patient outcomes in order for nurses to provide cost-effective care. Propensity scores were a useful method for determining the effect of nursing surveillance on hospital cost in this observational study. CLINICAL RELEVANCE: The results of this study along with possible clinical benefits would indicate that frequent nursing surveillance is important and might support the need for additional nursing staff to deliver frequent surveillance.     

Effect of Time of Day and Duration into Shift on Hazardous Exposures to Biological Fluids

Objective: To determine whether hospital employee biological hazardous exposure rates varied with time of day or increased with time interval'into shift.
Methods: This was a retrospective occurrence report review conducted at a university hospital with an emergency medicine residency program. Health care worker biological hazardous exposure data over a 30–month period were reviewed. Professional status, date, time, and type of exposure (needlestick, laceration, splash), time interval into shift of exposure, and hospital location of exposure were recorded. Hourly employee counts and risky procedure counts were matched by location with each reported exposure, to determine hourly rates of biological hazardous exposures.
Results: Analysis of 411 recorded exposures demonstrated that more people were exposed between 9:00 am and 1:00 am (p < 0.05), yet the exposure risk did not vary significantly when expressed as the number of exposures per worker or per procedure. Of the 393 exposures with data describing time interval into shift when the exposure occurred, significant numbers of exposures occurred during the first hour and at shift's end [when corrected for exposures per worker (p < 0.05) or exposures per procedure (p < 0.05)].
Conclusion: While the number of exposures are increased in the am hours, the exposure rate (as a function of workers or procedures) does not vary with time of the day. However, the exposure rate is increased during the first hour and last 2 hours of a shift. Efforts to increase worker precautions at the beginning and end of shifts are warranted.     

Association of Out-of-hospital Criteria with Need for Hospital Admission

Objective: To validate high-risk historical and physiologic out-of-hospital criteria as predictors of the need for hospitalization following ED evaluation.
Methods: Consecutive patients entered into the Suffolk County advanced life support system were enrolled. Previously proposed historical and physiologic "high-risk" criteria for hospitalization were prospectively collected. Criteria were associated with the need for hospital admission following ED evaluation.
Results: 1,238 patients were enrolled; 391 were released from an ED after transport. Most patients (843/1,238; 68%) were admitted to a hospital; and four died in the ED. Factors associated with an increased likelihood of admission or death among the transported patients were: bradycardia (90% admitted, p < 0.02); hypotension (80%, p < 0.03); hypertension (89%, p < 0.03); and age > 55 years (81%, p < 0.0001). Unresponsiveness and other abnormal vital signs were not associated with admission on univariate analysis. Logistic regression analysis identified two other factors associated with admission or death: tachycardia (72%, admitted, p < 0.01) and head injury (78% admitted. p < 0.001).
Conclusions: Abnormal pulse or blood pressure, head injury, and age > 55 years are associated with patients' requiring hospital admission after accessing the emergency medical services system. These criteria may aid the design of out-of-hospital refusal-of-care policies.     

Demographic Factors and Their Association with Outcomes in Pediatric Submersion Injury

Objectives: To describe the epidemiology and outcomes of serious pediatric submersion injuries and to identify factors associated with an increased risk of death or chronic disability.
Methods: A retrospective database review of 1994–2000 Massachusetts death and hospital discharge data characterized demographic factors; International Classification of Diseases, Ninth Revision (ICD-9), Clinical Modification (ICD-9-CM), or ICD-10 injury codes; and outcomes for state residents 0–19 years of age identified with unintentional submersion injuries. The authors performed logistic regression analysis to correlate outcomes with risk and demographic factors.
Results: The database included 267 cases of serious submersion injury, defined as those requiring hospitalization or leading to death. Of these 267 patients, 125 (47%) drowned, 118 (44%) were discharged home, 13 (5%) were discharged home with intravenous therapy or with availability of a home health aide, and 11 (4%) were discharged to an intermediate care/chronic care facility. The authors observed a trend of improved outcome in successively younger age groups (p < 0.0001). The multivariable logistic regression analysis showed an increased likelihood of poor outcome for males compared with females (odds ratio [OR]: 2.52; 95% confidence interval [95% CI] = 1.31 to 4.84) and for African Americans compared with whites (OR: 3.47; 95% CI = 1.24 to 9.75), and a decreased likelihood of poor outcome for Hispanics compared with whites (OR: 0.056; 95% CI = 0.013 to 0.24).
Conclusions: After serious pediatric submersion injuries, the overall outcome appears largely bimodal, with children primarily discharged home or dying. The observations that better outcomes occurred among younger age groups, females, and Hispanic children, with worse outcomes in African American children, suggest that injury prevention for submersion injuries should consider differences in age, gender, and race/ethnicity.     

Cerumen Occlusion Lowers Infrared Tympanic Membrane Temperature Measurement

Objective: To examine the effect that cerumen occlusion of the ear canal has on infrared tympanic membrane temperature measurement.
Methods: A prospective, randomized, single-blind human study was carried out in a university hospital observation unit. The subjects were a convenience sample of human volunteers aged 18 years or older who did not have cerumen occlusion or scarred tympanic membranes. A paraffin-coated human cerumen plug was placed in one randomly chosen ear, and after 20 minutes of equilibration the temperature in each ear was measured with an infrared thermometer. Analysis of the difference in mean temperature between the occluded and nonoccluded ears was by Student's paired t-test.
Results: Infrared tympanic membrane temperatures were measured in 43 subjects aged 21 to 58 years. The mean temperature of the occluded ear canal was 0.3°C lower than that of the opposite ear canal (p = 0.0001, 95% CI 0.16–0.45°C).
Conclusion: Cerumen occlusion of the ear canal causes underestimation of body temperature measured by infrared tympanic membrane thermometry.     

Causes and Patterns of Injury from Ladder Falls

Objectives: To review all ladder fall injuries seen in a community ED and to identify patterns of injury, factors that contribute to falls, and what pre-event and event factors could have reduced the likelihood of a fall or a resulting injury.
Methods: This was a retrospective, observational study involving patients who presented to a community hospital ED from January 1993 through December 1995 with injuries from a ladder fall. The medical records of all patients were reviewed. Patients then underwent a structured telephone interview to provide additional information about the circumstances of the fall.
Results: There were 59 patients who sustained injuries relating to ladder falls. All were adults, aged >18 years (mean 42.9 ± 16.2 years), were predominantly male (93%), and had fallen a distance of 1–15 feet (mean 7.2 ± 3.6 feet). Thirteen percent were admitted to the hospital, and there was 1 death. Fractures were observed in 21 patients (36%) and usually involved an extremity (77%). There was no relationship between the distance fallen and the occurrence of fracture. Other primary injuries included sprain (27%), contusion (24%), laceration (10%), abrasion (3%), and subdural hematoma (2%). Of the 59 patients, 42 (71%) were contacted directly. Most falls (79%) resulted from excessive reaching or incorrect ladder placement. Fifty percent of the described falls were occupationally related.
Conclusions: Falls from ladders, both in the occupational and nonoccupational settings, often result in significant injury. Simple safety measures may have prevented the majority of falls in this study. Public health efforts should emphasize education on safe ladder practices and techniques to reduce the possibility of injury in the event of a fall.     

Surveillance effects on community physician test ordering

The announcement that orders for long-term electrocardiograms were the subject of study in a community hospital was followed by a decrease in ordering rate of 30% from the corresponding quarter in the previous year. In succeeding quarters the decrement from corresponding quarters in the prior year was 21%, 27%, and 6%. Thereafter the ordering rate began to increase at a rate of 75% per year. In another community hospital in a contiguous town in which no surveillance was undertaken, the ordering rate for long-term electrocardiogram grew persistently at the rate of 42% per year over the same 3-year interval. The cardiologists at the community hospital under study behaved no differently as a group than other physicians in the community. The data strongly suggest that announced surveillance had the effect of diminishing long-term electrocardiogram tests ordered by community physicians by at least 20% for a period that lasts up to 9 months.     

Statistical models to predict the need for postoperative intensive care and hospitalization in pediatric surgical patients

OBJECTIVE: To develop statistical models for predicting postoperative hospital and ICU stay in pediatric surgical patients based on preoperative clinical characteristics and operative factors related to the degree of surgical stress. We hypothesized that preoperative and operative factors will predict the need for ICU admission and may be used to forecast the length of ICU stay or postoperative hospital stay. DESIGN: Prospective data collection from 1,763 patients. SETTING: Tertiary care children's hospital. PATIENTS AND PARTICIPANTS: All pediatric surgical patients, including those undergoing day surgery. Patients undergoing dental or ophthalmologic surgical procedures were excluded. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: A logistic regression model predicting ICU admission was developed from all patients. Poissonregression models were developed from 1,161 randomly selected patients and validated from the remaining 602 patients. The logistic regression model for ICU admission was highlypredictive (area under the receiver operating characteristics (ROC) curve = 0.981). In the data set used for development of Poisson regression models, significant correlations occurred between the observed and predicted ICU stay (Pearson r = 0.468, p < 0.0001, n = 131) and between the observed and predicted hospital stay for patients undergoing general (r = 0.695, p < 0.0001), orthopedic (r = 0.717, p < 0.0001), cardiothoracic (r = 0.746, p < 0.0001), urologic (r = 0.458, p < 0.0001), otorhinolaryngologic (r = 0.962, p < 0.0001), neurosurgical (r = 0.7084, p < 0.0001) and plastic surgical (r = 0.854, p < 0.0001) procedures. In the validation data set, correlations between predicted and observed hospital stay were significant for general (p < 0.0001), orthopedic (p < 0.0001), cardiothoracic (p = 0.0321) and urologic surgery (p = 0.0383). The Poisson models for length of ICU stay, otorhinolaryngology, neurosurgery or plastic surgery could not be validated because of small numbers of patients. CONCLUSIONS: Preoperative and operative factors may be used to develop statistical models predicting the need for ICU admission in pediatric surgical patients, and hospital stay following general surgical, orthopedic, cardiothoracic and urologic procedures. These statistical models need to be refined and validatedfurther, perhaps using data collection from multiple institutions.     

Out-of-hospital Spinal Immobilization: Its Effect on Neurologic Injury

Objective: To examine the effect of emergency immobilization on neurologic outcome of patients who have blunt traumatic spinal injuries.
Methods: A 5-year retrospective chart review was carried out at 2 university hospitals. All patients with acute blunt traumatic spinal or spinal cord injuries transported directly from the injury site to the hospital were entered. None of the 120 patients seen at the University of Malaya had spinal immobilization during transport, whereas all 334 patients seen at the University of New Mexico did. The 2 hospitals were comparable in physician training and clinical resources. Neurologic injuries were assigned to 2 categories, disabling or not disabling, by 2 physicians acting independently and blinded to the hospital of origin. Data were analyzed using multivariate logistic regression, with hospital location, patient age, gender, anatomic level of injury, and injury mechanism serving as explanatory variables.
Results: There was less neurologic disability in the unimmobilized Malaysian patients (OR 2.03; 95% CI 1.03–3.99; p = 0.04). This corresponds to a <2% chance that immobilization has any beneficial effect. Results were similar when the analysis was limited to patients with cervical injuries (OR 1.52; 95% CI 0.64–3.62; p = 0.34).
Conclusion: Out-of-hospital immobilization has little or no effect on neurologic outcome in patients with blunt spinal injuries.     

Risk-adjusted increases in medical resource utilization associated with health care-associated infections in gastrectomy patients

Rationale, aims and objectives  Quantifying the impact of health care-associated infections (HAIs) on medical resource utilization is necessary for payers and providers to appropriately allocate limited resources for interventions. However, previous studies tend to involve single institutions and do not take into account patient and practice variations between several hospitals. The objective of this study was to conduct a multi-institutional risk-adjusted comparison of HAI-associated impact on medical resources in gastrectomy patients in Japan.
Methods  Health care-associated infections were identified using a combination of International Classification of Diseases-10 codes and antibiotic utilization patterns in 1058 gastrectomy patients from 10 Japanese hospitals. Multiple linear regression models and risk adjustment were used to analyse the impact of HAIs on: (1) total hospital costs; (2) antibiotic costs; and (3) post-surgical length of stay (LOS).
Results  Overall HAI incidence for the database was 20.3%, with a range of 8.8–29.6% among the 10 hospitals. Regression models showed that HAIs were significantly associated with increases in all three indicators. Risk-adjusted comparisons revealed that HAIs were associated with an increase of US$2767 (range: US$1035–6513) in overall hospital cost, US$202 (US$98.8–764.6) antibiotic costs and 10.6 (4.7–24 days) post-surgical LOS days.
Conclusions  Even after adjusting for patient characteristics and other variables, there was still a high degree of variation observed in the impact of HAIs on total hospital costs and antibiotic costs from a third-party payer's perspective and post-surgical LOS among the 10 hospitals. This information can increase the efficiency of allocation of resources for interventions to reduce HAIs.     

Subarachnoid Hemorrhage Diagnosis: Lumbar Puncture Is Still Needed When the Computed Tomography Scan Is Normal

Objectives: To determine the sensitivity of third-generation CT scanners for diagnosed nontraumatic subarachnoid hemorrhage (SAH) and to assess the impact of symptom duration on sensitivity.
Methods: A retrospective chart review was performed in a university-affiliated tertiary care hospital with an annual ED volume of >100,000 patients. The target population was all patients who presented to the ED from January 1991 to September 1994 with symptoms suggestive of SAH and who had a final diagnosis of nontraumatic SAH based on either a positive CT scan or positive spinal fluid analysis. Patients referred from outside facilities were included if they had a CT done at the study site. All CT scans were done using third-generation scanners. Official CT scan reports were used to categorize scans as positive or negative.
Results: There were 140 patients identified with SAH, with a mean age of 56 years (range 10–88). The sensitivity of CT in the diagnosis of nontraumatic SAH when performed at or before 12 hours of symptom duration was 100% (80/80), and 81.7% (49/60) after 12 hours of symptom duration (95% CI 95–100% and 69.5–90.4%, respectively; p < 0.0001). Eleven of the 140 patients had a negative CT and positive spinal fluid analysis, yielding an overall sensitivity of 92.1% (129/140).
Conclusion: The sensitivity of third-generation CT scans for SAH decreases with time from the onset of symptoms. In this sample population, CT was able to detect all patients scanned ^12 hours after symptom onset. Although the study demonstrated good sensitivity of CT scan reports for SAH when the scan was performed after S12 hours of symptom onset, additional real-time experience is needed to better define the potential risk of a missed SAH should this population not receive the customary lumbar puncture examination in the setting of a negative CT scan.     

Prediction of interatrial and interventricular electromechanical delays from P/QRS measurements: value for pacemaker timing optimization

Summary: Cardiac pacing creates spurious delays between and within the cardiac chambers. These are: 1. Left atrial (LA) transport delay (ATD) either sensed (s) or paced (p), (time from right atrial P-wave to the end of LA transport (mitral Doppler A-wave)). 2. Interventricular delay (IVD), (time from onsets of right (RV) to left ventricular (LV) contractions). 3. P-sense offset (PSO), (time from P-onset to P-detection). Thus, restoration of left heart atrioventricular (AV) synchrony can be accomplished by compensating above delays, according to a previously published equation: RAV = ATD-IVD-PSO, where RAV = right heart AV.
Objective: To test the hypothesis that ATD could be predicted from Ps and Pp, and that interventricular delay (IVD) could be predicted from QRSp, using three-lead surface electrocardiograms (ECGs).
Methods: Thirty-six patients aged 63.5 ± 15.5 years, 64% males, all with previously implanted DDD pacemakers, were studied by echo-Doppler and surface ECG obtained with a pacemaker programmer. Measurements included Ps; Pp; intrinsic QRSs; and paced QRSp, ATDs, ATDp, and IVD (difference between RVp and RVs left preejection intervals, PEI). Regressions between ECG and echo-Doppler intervals were calculated.
Results: Regressions and correlation coefficients: ATD (s+p) = 0.96*P + 55 (R = 0.94, P < 0.0001); PEIp = 0.75 * QRSp + 34.8 (R = 0.89, P< 0.0001); IVD = 0.39 *QRSp – 7.9 ms (R = 0.87, P = 0.002).
Conclusions: Inter-atrial and inter-ventricular electromechanical delays can be predicted from P-wave and QRS durations. These measurements allow AV delay optimization in DDD and cardiac resynchronization therapy devices with no need of Doppler echocardiography.