Reducing failed extubations in the intensive care unit

BACKGROUND: Failed extubation is associated with substantially increased morbidity, mortality, and costs for patients receiving mechanical ventilation. A study was designed in 1998 to identify risk factors for failed extubation and use a quality improvement model to reduce failed extubation rates in a surgical intensive care unit (SICU) in an academic hospital. METHODS: Study design involved a prospective cohort SICU with a concurrent control SICU. The primary outcome was rate of failed extubations per 1,000 ventilator days. Information on risk factors for failed extubations was also collected. Performance improvement staff identified failed extubation patients, and respiratory therapy provided information on ventilator days. The quality improvement model implemented three phases between October 1998 and June 2000: (1) identifying factors associated with failed extubation, (2) developing a guideline to reduce failed extubation, and (3) implementing the guideline. RESULTS: Significant factors associated with failed extubation included suctioning more frequently than every 4 hours versus the current model of "every 4 hours or greater" (odds ratio [OR] 11.3; 95% confidence interval [CI] 1.5-88.3), being agitated or sedated versus being alert (OR 4.5, CI: 1.2-14.7), and oxygen saturation < or = 95% versus > or = 95% (OR 4.0; CI: 1.2-13). Failed extubation rate in the SICU decreased from 8/1,000 in October 1998 to 1.5/1,000 in June 2000, and control SICU rates remained unchanged (8/1,000). DISCUSSION: The intervention significantly reduced the rate of failed extubation in the SICU. By employing a quality improvement model and identifying risk factors for failed extubation, providers should be able to decrease risk of failed extubation for SICU patients.     

A Web-based diabetes care management support system

BACKGROUND: Because of the often asymptomatic nature of diabetes and the long period between sustained hyperglycemia and observable complications, appropriate diabetes care relies on a long-term program of secondary prevention. Yet routine monitoring and screening among patients with diabetes is less than optimal. To support the provision of routine care to patients with diabetes, the Center for Health Services Research, Henry Ford Health System (Detroit), developed a Web-based Diabetes Care Management Support System (DCMSS). A nonrandomized, longitudinal study was conducted (January 1, 1998-October 31, 1999) with 13,325 health maintenance organization patients with diabetes who were aligned to 190 primary care providers practicing in 31 primary care clinics. RESULTS: Three DCMSS features--clinical practice guidelines, patient registries, and performance reports--were made available via a corporate intranet within an existing electronic medical record. The effect of DCMSS usage frequency was evaluated on the likelihood of a patient's receipt of glycated hemoglobin testing, lipid profile testing, and retinal examinations. Logistic regression models controlling for patient sociodemographic and clinical characteristics, and the testing history of the patient, the primary care physician, and the primary care clinic, were fit using generalized estimating equation methods. The more often a physician used DCMSS, the more likely his or her patients were to receive lipid profile testing (OR [odds ratio] = 1.01, 95% CI [confidence interval] = 1.01-1.02). Compared with patients of physicians who never used the system, patients of physicians who initiated 12 sessions were an estimated 19% more likely (95% CI = 7%-33%) to receive lipid profile testing. The analyses also suggested that the likelihood of a patient receiving a retinal exam was associated with system usage (OR = 1.01, 95% CI = 1.01-1.01). No relationship was found between system use and glycated hemoglobin testing. CONCLUSIONS: Computerized systems of clinical practice guidelines, patient registries, and performance feedback may help improve the rate of routine testing among patients with diabetes.     

Who may not benefit from continuous renal replacement therapy in acute kidney injury?

This study aimed to identify factors that may predict early kidney recovery (less than 48 hours) or early death (within 48 hours) after initiating continuous renal replacement therapy (CRRT) in acute kidney injury (AKI) patients. This is a multicenter retrospective observational study of 14 Japanese Intensive care units (ICUs) in 12 tertiary hospitals. Consecutive adult patients with severe AKI requiring CRRT admitted to the participating ICUs in 2010 (n = 343) were included. Patient characteristics, variables at CRRT initiation, settings, and outcomes were collected. Patients were grouped into early kidney recovery group (CRRT discontinuation within 48 hours after initiation, n = 52), early death group (death within 48 hours after CRRT initiation, n = 52), and the rest as the control group (n = 239). The mean duration of CRRT in the early kidney recovery group and early death group was 1.3 and 0.9 days, respectively. In multivariable regression analysis, in comparison with the control group, urine output (mL/h) (odds ratio [OR]: 1.02, 95% confidence interval [CI]: 1.01–1.03), duration between ICU admission to CRRT initiation (days) (OR: 0.65, 95% CI: 0.43–0.87), and the sepsis‐related organ failure assessment score (OR: 0.87, 95% CI; 0.78–0.96) were related to early kidney recovery. Serum lactate (mmol/L) (OR: 1.19, 95% CI: 1.11–1.28), albumin (g/dL) (OR: 0.52, 95% CI: 0.28–0.92), vasopressor use (OR: 3.68, 95% CI: 1.37–12.16), and neurological disease (OR: 9.64, 96% CI: 1.22–92.95) were related to early death. Identifying AKI patients who do not benefit from CRRT and differentiating such patients from the study cohort may allow previous and future studies to effectively evaluate the indication and role of CRRT.     

Uncertainties in doses calculated according to ICRP recommendations after inhalation of 239PUO2 and early chest monitoring

This study estimates uncertainties in Pu biokinetics and effective doses calculated after an acute inhalation exposure to (239)PuO(2) according to ICRP recommendations (default values for aerosols size and PuO(2) dissolution parameters). This was performed using the most recently reported variations in model parameters and simulations after a Monte Carlo approach. Without chest monitoring, uncertainties in thoracic retention and plutonium excretion was 8-10 (95% confidence interval as the ratio between 97.5 and 2.5 percentiles of the lognormal distributions) up to 900 d after exposure. Early chest monitoring reduces significantly the uncertainties in plutonium biokinetics and doses which remain within a 95% confidence interval of 2.3 as compared with 6.6, without monitoring. Analysis of bioassay data previously reported shows that the dose delivered to some individuals can be out of the confidence interval, which was mostly due to an inhibition of the late mechanical clearance of the alveolar interstitium.     

Can a renal nurse assess fluid status using ultrasound on the inferior vena cava? A cross‐sectional interrater study

Introduction: Ultrasound of the inferior vena cava (IVC‐US) has been used to estimate intravascular volume status and fluid removal during a hemodialysis session. Usually, renal nurses rely on other, imprecise methods to determine ultrafiltration. To date, no study has examined whether renal nurses can reliably perform ultrasound for volume assessment and for potential prevention of intradialytic hypotension. This pilot study aimed to determine if a renal nurse could master the skill of performing and correctly interpreting Point of Care Ultrasound on patients receiving hemodialysis. Methods: After receiving theoretical training and performing 100 training scans, a renal nurse performed 60 ultrasound scans on 10 patients. These were categorized by the nurse into hypovolemic, euvolemic, or hypervolemic through measurement of the maximal diameter and degree of collapse of the IVC. Scans were subsequently assessed for adequacy and quality by two sonologists, who were blinded to each other's and the nurse's results. Findings: The interrater reliability of 60 scans was good, with intraclass correlation 0.79 (95% confidence interval (CI) =0.63–0.87) and with a good interrater agreement for the following estimation of intravascular volume (Cohen's weighted Kappa κ_w = 0.62), when comparing the nurse to an expert sonographer. Discussion: A renal nurse can reliably perform ultrasound of the IVC in hemodialysis patients, obtaining high quality scans for volume assessment of hemodialysis patients. This novel approach could be more routinely applied by other renal nurses to obtain objective measures of patient volume status in the dialysis setting.     

Evaluation of inter-organizational traffic injury prevention in a WHO safe community

The objective of the study was to examine the effect of a community-based injury prevention program on traffic injuries. A population-based quasi-experimental design was used with pre- and post-implementation measurements in an intervention and a control area. The program was based on inter-organizational participation in detecting and taking action against traffic injuries. The total relative risk for traffic injury in the study area showed only a tendency to decrease following program exposure (odds ratio 0.91; 95% confidence interval 0.81-1.02). No change in relative risk was observed in the control area. The analyses of program impact on injury severity showed that the relative risk for moderate injuries in the study area was reduced by almost half (odds ratio 0.59; 95% confidence interval 0.49-0.69), the risk for severe or fatal injuries remained constant (odds ratio 1.27; 95% confidence interval 0.80-2.02), and the risk for minor injuries increased (odds ratio 1.34; 95% confidence interval 1.13-1.59). The relative risk for moderate injuries was reduced by at least half for mopedists, cyclists, pedestrians, and those leaving or entering a motor vehicle. Community-based injury prevention can be a complement to national traffic safety programs.     

Automated segmentation of retinal blood vessels and identification of proliferative diabetic retinopathy

Proliferative diabetic retinopathy can lead to blindness. However, early recognition allows appropriate, timely intervention. Fluorescein-labeled retinal blood vessels of 27 digital images were automatically segmented using the Gabor wavelet transform and classified using traditional features such as area, perimeter, and an additional five morphological features based on the derivatives-of-Gaussian wavelet-derived data. Discriminant analysis indicated that traditional features do not detect early proliferative retinopathy. The best single feature for discrimination was the wavelet curvature with an area under the curve (AUC) of 0.76. Linear discriminant analysis with a selection of six features achieved an AUC of 0.90 (0.73-0.97, 95% confidence interval). The wavelet method was able to segment retinal blood vessels and classify the images according to the presence or absence of proliferative retinopathy.     

Associations among nocturnal sleep,daytime intradialytic sleep,and mortality risk in patients on daytime conventional hemodialysis: US Renal Data System special study data

Fragmented nocturnal sleep is commonly reported by patients undergoing daytime conventional hemodialysis (CHD) and may be associated with higher mortality risk. Subjective sleepiness during CHD is also frequently observed. We examined the association of reported sleep fragmentation and nocturnal and daytime (intradialytic) sleep durations with survival in a national cohort of 1440 CHD patients who were interviewed in 2005–2007 in a phone survey conducted by the US Renal Data System. Patient survival was followed through September 30, 2010 in the US Renal Data System. A total of 76% of patients reported that they typically dozed off or slept during their treatment, and intradialytic dozing was especially common among patients whose treatment shift started before 1000 hours. There was a trend for patients who reported dozing during CHD to report nocturnal sleep fragmentation (60.4% vs. 55.1%; P = 0.07). With adjustment for intradialytic sleep and other covariates, nocturnal sleep fragmentation was not associated with survival. Mortality risk was higher for patients who reported sleeping 9 or more hours/night compared with the referent category of nocturnal sleep equal to 6–7 hours (hazard ratio: 1.50 [95% confidence interval: 1.04–2.17]; P = 0.03). Continued investigation of the association of timing and duration of sleep with hemodialysis patient outcomes is warranted.     

Predialysis volume overload and patient‐reported sleep duration and quality in patients receiving hemodialysis

Introduction: Previous studies of patients with end‐stage renal disease have examined the role of fluid shifts on apnea‐hypopnea episodes, but the association between volume overload and patient‐reported sleep quality or duration has not been well‐established. Methods: We studied the association between predialysis bioimpedance spectroscopy‐derived volume estimates and self‐reported sleep quality and duration in 638 patients in the United States Renal Data System ACTIVE/ADIPOSE study receiving hemodialysis from 2009 to 2011. We used questionnaires to assess self‐reported sleep duration and quality. We used relative hydration status (fluid overload/extracellular water; FO/ECW) as the primary predictor and examined associations with hours of sleep duration using linear regression. We used multivariable ordinal logistic regression to determine the association between categories of relative hydration status (normal hydration [FO/ECW < 6.8%], mild overhydration [FO/ECW 6.8%–15%], and hyperhydration [FO/ECW > 15%]) and four levels of difficulty with falling asleep, waking, and returning to sleep. Findings: Higher relative hydration status was associated with fewer hours of sleep (?0.31 hours per 10%, 95% confidence interval (CI) ?0.49 to ?0.13). Compared to the normal hydration group, there was a statistically significant association between higher relative hydration status category and more frequent nighttime waking (OR: mild overhydration 1.92 [95% CI 1.23–2.99], hyperhydration 1.87 [95% CI 1.16–2.99]), a trend toward more difficulty returning to sleep (OR: mild overhydration 1.46 [95% CI 0.94–2.27], hyperhydration 1.52 [95% CI 0.95–2.43]), and no association between relative hydration category and difficulty falling asleep. Discussion: Hydration status was associated with self‐reported sleep duration in patients on dialysis. Future studies should prospectively examine the effects of optimizing fluid status on sleep duration and quality.     

Impact of arterial microcalcification of the vascular access on cardiovascular mortality in hemodialysis patients

Gross vascular calcification seen on imaging studies is common in hemodialysis (HD) patients, and is a significant predictor for cardiovascular mortality in HD patients. We have reported that arterial microcalcification (AMiC) of the vascular access is associated with increased aortic stiffness. This study investigated the impact of vascular access AMiC on cardiovascular mortality in HD patients. The study included 149 HD patients (mean age: 59.1 ± 13.9 years, 86 men and 63 women, 65.8% diabetic) who underwent vascular access surgery. Radial or brachial artery specimens were obtained intraoperatively, and pathologic examination was performed using von Kossa stain to identify AMiC. We compared all‐cause and cardiovascular mortality between patients with and without AMiC. The mean follow‐up was 37.8 ± 34.5 months, and AMiC was present in 38.8% (n = 57) of patients. The presence of diabetes (odds ratio: 16.49, 95% confidence interval: 1.81–150.36, P = 0.013) was the only independent risk factor for vascular access AMiC. During the observational period, there were 27 cardiovascular deaths. Kaplan–Meier analysis showed an increased cardiovascular mortality risk (log rank = 4.83, P = 0.028) in AMiC patients, and Cox regression analysis confirmed that AMiC was an independent predictor for cardiovascular mortality (hazard ratio: 2.35, 95% confidence interval: 1.09–5.09, P = 0.030). In conclusion, vascular access AMiC is a strong risk factor for cardiovascular mortality in HD patients.     

Evaluation of the Click It or Ticket intervention in Utah

Objective

To evaluate the Click It or Ticket (CIOT) intervention conducted in Utah by comparing changes in safety belt use using observational safety belt surveys pre- and post-intervention.

Methods

Observational surveys of safety belt use for drivers and front seat passengers (collectively referred to as front seat occupants) were conducted before and after the media and enforcement blitz of the CIOT intervention. Data were collected from 16 urban sites during the daytime and nighttime. Logistic regression and generalized estimating equations were used to compute odds ratios for safety belt use adjusted for front seat occupant characteristics.

Results

Overall safety belt use was observed at 76.5% pre-intervention and 84.8% post-intervention, an improvement of 8.3% (95% confidence interval [CI]: 5.2%, 11.3%). Daytime and nighttime safety belt use improved by 7.8% (95% CI: 3.5%, 12.1%) and 9.7% (95% CI: 6.4%, 13.0%), respectively. While males showed a greater improvement (9.9%) in safety belt use when compared to females (5.7%); males were still less likely to use safety belts than females.

Conclusions

The CIOT intervention is associated with increased safety belt use at the sites observed in Utah, including among the two high risk groups targeted by the intervention: nighttime occupants and males.     

Antibiotic lock: In vitro stability of vancomycin and four percent sodium citrate stored in dialysis catheters at 37°C

Catheter-related bacteremia (CRB) is a major cause of morbidity and mortality especially among patients receiving hemodialysis (HD). Antibiotic lock therapy represents a promising technique in the treatment of CRB. Several studies have evaluated antibiotics in combination with heparin as an interdialytic locking solution as adjunctive therapy for CRB. The objective of this study was to evaluate the chemical stability of the vancomycin in 4% sodium citrate in HD catheters as an interdialytic lock. Vancomycin was prepared and diluted with sodium citrate 4% and stored in polyvinyl chloride syringes, 2 carbothane dialysis catheters (Hemostar^®) and 2 dual floating HD catheters (CardioMed^®). Syringes were stored at 4 °C or 23 °C and the catheters were stored in an incubator at 37 °C for 72 hours. Samples underwent daily chromatographic analysis and the luminal concentration of vancomycn was determined on study days 0, 1, and 3. When vancomycin is reconstituted with normal saline to achieve a concentration of 50 mg/mL, and then further diluted in 4% sodium citrate, to achieve concentrations of either 1 or 3 mg/mL, and then stored at 4 °C, room temperature, or 37 °C, solutions were observed to retain >92% of the initial concentration for the study period of 3 days. Based on the fastest degradation rate determined with 95% confidence interval, >90% is retained for 6.53 days. We conclude that vancomycin—4% citrate solutions stored in polyvinyl chloride syringes or HD catheters are not significantly affected by temperature or concentration within the 72 hours storage period. Therefore, these solutions can be anticipated to be suitable as a HD interdialytic antibiotic lock in standard HD catheters.     

High-accuracy gas analysis via isotope dilution mass spectrometry: carbon dioxide in air

An absolute method, based on isotope dilution mass spectrometry, is described for the determination of atmospheric concentrations of carbon dioxide (CO2) in dry air. In this study, the relative amounts of sample and spike gases are measured manometrically under temperature control before blending. The spike CO2 composition is approximately 0.1 atom % 13C while the oxygen isotopic composition is "normal". Exhaustive assessment of potential error sources leads to accountability of observed imprecision and determination of accuracy confidence intervals (CI). The imprecision interval (95% CI) about the mean is smaller than +/- 0.1% (+/- 0.4 mumol/mol) while the accuracy interval (95% CI) is +/- 0.15% (+/- 0.52 mumol/mol) for air having a CO2 concentration of about 350 mumol/mol. Calculated concentrations of CO2 are statistically indistinguishable from those generated by gravimetry, an independent method of analysis. In this study, the major contributors to uncertainty and imprecision are the predetermination of the gas volume ratio and the measurement of the isotopic composition of the blended CO2, respectively.     

Two-color planar laser-induced fluorescence thermometry in aqueous solutions

We demonstrate a two-color planar laser-induced fluorescence technique for obtaining two-dimensional temperature images in water. For this method, a pulsed Nd:YAG laser at 532 nm excites a solution of temperature-sensitive rhodamine 560 and temperature-insensitive sulforhodamine 640. The resulting emissions are optically separated through filters and detected via a charged-couple device (CCD) camera system. A ratio of the two images yields temperature images independent of incident irradiance. An uncertainty in temperature of +/- 1.4 degrees C is established at the 95% confidence interval.     

Prevalence of motor vehicle crashes involving drowsy drivers,United States, 1999–2008

The proportion of motor vehicle crashes that involve a drowsy driver likely is greater than existing crash databases reflect, due to the possibility that some drivers whose pre-crash state of attention was unknown may have been drowsy. This study estimated the proportion of crashes that involved a drowsy driver in a representative sample of 47,597 crashes in the United States from 1999 through 2008 that involved a passenger vehicle that was towed from the scene. Multiple imputation was used to address missing data on driver drowsiness. In the original (non-imputed) data, 3.9% of all crashes, 7.7% of non-fatal crashes that resulted in hospital admission, and 3.6% of fatal crashes involved a driver coded as drowsy; however, the drowsiness status of 45% of drivers was unknown. In the imputed data, an estimated 7.0% of all crashes (95% confidence interval: 4.6%, 9.3%), 13.1% of non-fatal crashes that resulted in hospital admission (95% confidence interval: 8.8%, 17.3%), and 16.5% of fatal crashes (95% confidence interval: 12.5%, 20.6%) involved a drowsy driver. Results suggest that the prevalence of fatal crashes that involve a drowsy driver is over 350% greater than has been reported previously.     

Fatigue, sleep restriction and driving performance

We ran a randomized cross-over design study under sleep-deprived and non-sleep-deprived driving conditions to test the effects of sleep restriction on real driving performance. The study was performed in a sleep laboratory and on an open French highway. Twenty-two healthy male subjects (age = 21.5 +/- 2 years; distance driven per year = 12,225 +/- 4739 km (7641 +/- 2962 miles) [mean +/- S.D.]) drove 1000 km (625 miles) over 10 h during five 105 min sessions on an open highway. Self-rated fatigue and sleepiness before each session, number of inappropriate line crossings from video recordings and simple reaction time (RT) were measured. Total crossings increased after sleep restriction (535 crossings in the sleep-restricted condition versus 66 after non-restricted sleep (incidence rate ratio (IRR): 8.1; 95% confidence interval (95% CI): 3.2-20.5; p < 0.001)), from the first driving session. The interaction between the two factors (conditionxtime of day) was also significant (F(5, 105) = 3.229; p < 0.05). Increasing sleepiness score was associated with increasing crossings during the next driving session in the sleep-restricted (IRR: 1.9; 95% CI: 1.4-2.4) but not in the non-restricted condition (IRR: 1.0; 95% CI: 0.8-1.3). Increasing self-perceived fatigue was not associated with increasing crossings in either condition (IRR: 0.95; 95% CI: 0.93-0.98 and IRR: 1.0; 95% CI: 0.98-1.02). Rested subjects drove 1000 km with four shorts breaks with only a minor performance decrease. Sleep restriction induced important performance degradation even though time awake (8h) and session driving times (105 min) were relatively short. Major inter-individual differences were observed under sleep restriction. Performance degradation was associated with sleepiness and not fatigue. Sleepiness combined with fatigue significantly affected RT. Road safety campaigns should encourage drivers to avoid driving after sleep restriction, even on relatively short trips especially if they feel sleepy.     

Effects of electronic stability control (ESC) on accidents: a review of empirical evidence

This study summarizes evidence from empirical studies on the effects of electronic stability control (ESC) on accidents in a meta-analysis. Large reductions of single vehicle accidents have been found (-49%; 95% confidence interval: [-55%; -42%]), and smaller but still significant reductions of head-on collisions (-13%; 95% confidence interval: [-17%; -8%]). Multi-vehicle fatal accidents are also significantly reduced (-32%; 95% confidence interval: [-43%; -20%]). The effects can be explained with the potential of ESC to improve driving dynamics and to reduce the probability of loss of control. However, there are significant amounts of heterogeneity in the results, especially for single vehicle accidents, and a sensitivity analysis shows that the results for single vehicle accidents are likely to be affected by publication bias. The results for single vehicle accidents are in excess of what might be expected based on studies that have estimated the total amount of accidents that may be affected by ESC. Consequently, the proportions of accidents that can be avoided by ESC is assumed to be somewhat smaller than suggested by most empirical studies. Properties of the vehicles, time trends, and driver behaviour may have contributed to the large empirical effects.     

On the mechanism of precipitation strengthening in Cu-z.sbnd;Ti alloys

We have measured the ratio R_a of flow stresses for aged Cu-2.5 w/o Ti at 77 K and room temperature. Specimens solution treated and then aged at 500°C for 1, 4 and 8 hours (the second aging peak in this alloy) exhibited an average R_a value of 0.99 ± 0.021 (95% confidence interval). This value strongly suggests order strengthening, as do other observations of coupled dislocations (5,8,13) and slip character (12). Since our measurements of particle-matrix mismatch show no change with temperature, the R_a value expected for coherency strain strengthening should accurately match the elastic modulus ratio of 1.08. The essentially unity value of R_a observed here appears to rule out significant coherency strain strengthening in Cu-2.5 w/o Ti.     

Effect of personalized nutritional counseling in maintenance hemodialysis patients

Monitoring nutritional parameters is an integral part of hemodialysis (HD) patient treatment program. The purpose of this study was to evaluate the impact of the personalized nutritional counseling (PNC) on calcium–phosphorus metabolism, potassium, albumin, protein intake, interdialytic weight gain (IDWG), body composition parameters and fluid overload in HD patients. This was a multicenter longitudinal intervention study with 6 months of follow‐up and 731 patients on maintenance HD from 34 dialysis units in Portugal were enrolled. Biochemical and body composition parameters were measured at baseline, 1, 3 and 6 months after the PNC. Patient's mean age was 64.9 (95% confidence interval [CI]: 63.8–66.0) years and mean HD time was 59.8 (95% CI: 55.3–64.3) months. Regarding data comparison collected before PNC vs. 6 months after, we obtained, respectively, the following results: patients with normalized protein catabolic rate (nPCR) ≥ 1 g/kg/day = 66.5% vs. 73.5% (P = 0.002); potassium > 5.5 mEq/L = 52% vs. 35.8% (P < 0.001); phosphorus between 3.5 and 5.5 mg/dL = 43.2% vs. 52.5% (P < 0.001); calcium/phosphorus (Ca/P) ratio ≤ 50 mg/dL = 73.2 % vs. 81.4% (P < 0.001); albumin ≥ 4.0 g/dL = 54.8% vs. 55% (P = 0.808); presence of relative overhydration = 22.4% vs. 25% (P = 0.283); IDWG > 4.5% = 22.3% vs. 18.2% (P = 0.068). PNC resulted in a significant decrease in the prevalence of hyperkalemia, hypophosphatemia and also showed amelioration in Ca/P ratio, nPCR and an increase in P of hyphosphatemic patients. Our study suggests that dietetic intervention contributes to the improvement of important nutritional parameters in patients receiving hemodialysis treatment.     

Comparison of reporting of seat belt use by police and crash investigators: variation in agreement by injury severity

Purpose: To evaluate agreement between police and trained investigators regarding seat belt use by crash victims, according to injury severity. Methods: We used data from the National Accident Sampling System Crashworthiness Data System (CDS) for front seat occupants, 16 years and older, in crashes during 1993–2000. Crashworthiness Data System investigators determined belt use from vehicle inspection, interviews, and medical record information; their assessment was considered the gold standard for this analysis. Occupant severity of injury was categorized in five levels from no injuries to death. We estimated the sensitivity, specificity, and area under receiver operating characteristic curves for police reports of belt use. Results: Among 48,858 occupants, sensitivity of a police report that a belt was used was 95.8% overall and varied only modestly by injury severity. Specificity of a police report that a belt was not used was 69.1% overall; it was the lowest among the uninjured (53.2%) and greatest among the dead (90.4%). The area under the curve was 0.82 (95% confidence interval 0.82–0.83) overall; this was lowest among those not injured (0.75, 95% confidence interval 0.74–0.76) and increased with injury severity to 0.91 (95% confidence interval 0.90–0.93) among those who died. Conclusion: Police usually classify belted crash victims as belted, regardless of injury severity. But they often classify unbelted survivors as belted when they were not. This misclassification may result in exaggerated estimates of seat belt effectiveness in some studies.