Appropriate use of the Glasgow Coma Scale in intubated patients: a linear regression prediction of the Glasgow verbal score from the Glasgow eye and motor scores

Use of scene vital signs improves TRISS predicted survival in intubated trauma patients

INTRODUCTION

The Trauma Related Injury Severity Score (TRISS) has been previously validated to predict outcomes in nonintubated, nonparalyzed trauma patients. The purpose of this study was to assess the impact of scene vital signs on predicting survival in intubated trauma patients.

METHODS

Our Trauma Registry of the American College of Surgeons was reviewed for all trauma patients admitted between 10/01/04 and 09/30/06, arriving by aeromedical transport. TRISS was evaluated for each patient based on their (1) scene vital signs and (2) arrival vital signs. Additionally, the "TRISS-like" score was calculated for each patient. Expected mortality for each score was measured against observed mortality.

RESULTS

Four thousand four hundred ninety-nine Trauma Registry of the American College of Surgeons patients were admitted during the study period; 695 (15%) were transported by air; 163 patients (23%) arrived intubated; 480 arrived nonintubated. Observed survival in the intubated group was 76%. Observed survival in the nonintubated group was 100%. TRISS using scene vital signs more closely predicted mortality among intubated patients than the other scoring systems (69% versus 39% using TRISS-arrival versus 80% using TRISS-like). Scene vital signs with TRISS also resulted in fewer "unexpected" outcomes (survivors and deaths).

CONCLUSIONS

Traditionally, patients arriving at trauma centers intubated are either excluded from the trauma registry or have their physiological score "modified" to account for pharmacologically altered respiratory rate and Glasgow Coma Scale. In intubated patients, TRISS using scene vital signs more reliably predicts survival and does so with far fewer "unexpected" outcomes than with other available scoring systems.

Traumatic brain injury: assessment, resuscitation and early management

This review examines the evidence base for the early management of head-injured patients. Traumatic brain injury (TBI) is common, carries a high morbidity and mortality, and has no specific treatment. The pathology of head injury is increasingly well understood. Mechanical forces result in shearing and compression of neuronal and vascular tissue at the time of impact. A series of pathological events may then ensue leading to further brain injury. This secondary injury may be amenable to intervention and is worsened by secondary physiological insults. Various risk factors for poor outcome after TBI have been identified. Most of these are fixed at the time of injury such as age, gender, mechanism of injury, and presenting signs (Glasgow Coma Scale and pupillary signs), but some such as hypotension and hypoxia are potential areas for medical intervention. There is very little evidence positively in favour of any treatments or packages of early care; however, prompt, specialist neurocritical care is associated with improved outcome. Various drugs that target specific pathways in the pathophysiology of brain injury have been the subject of animal and human research, but, to date, none has been proved to be successful in improving outcome.

The predictive value of field versus arrival Glasgow Coma Scale score and TRISS calculations in moderate-to-severe traumatic brain injury

BACKGROUND

Glasgow Coma Scale (GCS) scores are widely used to quantify level of consciousness in the prehospital environment. The predictive value of field versus arrival GCS is not well defined but has tremendous implications with regard to triage and therapeutic decisions as well as the use of various predictive scoring systems, such as Trauma Score and Injury Severity Score (TRISS). This study explores the predictive value of field GCS (fGCS) and arrival GCS (aGCS) as well as TRISS calculations using field (fTRISS) and arrival (aTRISS) data in patients with moderate-to-severe traumatic brain injury (TBI).

METHODS

Major trauma victims with head Abbreviated Injury Scores of 3 or greater were identified from our county trauma registry over a 16-year period. The predictive ability of fGCS with regard to aGCS was explored using univariate statistics and linear regression modeling. The difference between aGCS and fGCS was also modeled against mortality and the composite endpoint using logistic regression, adjusting for fGCS. The predictive value of preadmission GCS (pGCS), defined as either fGCS or aGCS in nonintubated patients without a documented fGCS, with regard to mortality and a composite endpoint representing the need for neurosurgical care (death, craniotomy, invasive intracranial pressure monitoring, or intensive care unit care >48 hours) was determined using receiver-operator curve (ROC) analysis. Finally, fTRISS and aTRISS predicted survival values were compared with each other and to observed survival.

RESULTS

A total of 12,882 patients were included. Mean values for fGCS and aGCS were similar (11.4 and 11.5, respectively, p = 0.336), and a strong correlation (r = 0.67, 95% CI 0.66-0.69, p < 0.0001) was observed between them. The difference between fGCS and aGCS was also predictive of outcome after adjusting for fGCS. Good predictive ability was observed for pGCS with regard to both mortality and neurosurgical intervention. Both fTRISS and aTRISS predicted survival values were nearly identical to observed survival. Observed and fTRISS predicted survival were nearly identical in patients undergoing prehospital intubation

CONCLUSIONS

Values for fGCS are highly predictive of aGCS, and both are associated with outcome from TBI. A change in GCS from the field to arrival is highly predictive of outcome. The use of field data for TRISS calculations appears to be a valid methodological approach, even in severely injured TBI patients undergoing prehospital intubation.

Assessing quality of care in a trauma referral center: benchmarking performance by TRISS-based statistics or by analysis of stratified ISS data?

BACKGROUND

Using prospectively collected data from Ulleval University Hospital in Norway, standard TRISS-based methods with case mix correction were compared with analysis based on ISS stratified data.

METHODS

Reference data were The Major Trauma Outcome Study (MTOS) controlled sites, used for calculation of AIS 90 based TRISS coefficients. Present TRISS convention requires RTS scoring on hospital admission, excluding many severely injured patients intubated before arrival. Therefore, all Ulleval patients were RTS scored using prehospital data if needed.

RESULTS

There was 6.6% of MTOS controlled sites patients (mortality rate 26.7%) that had been excluded before estimation of TRISS coefficients because of lack of data for Ps calculation. Analyses based on ISS stratified data included these patients and indicated significant better performance at Ulleval for blunt, but not for penetrating trauma. No TRISS-based analysis detected this difference.

CONCLUSIONS

The RTS convention should be changed to reduce patient exclusion. Presently, stratified ISS based data should also be analyzed.

The association between field Glasgow Coma Scale score and outcome in patients undergoing paramedic rapid sequence intubation

Early intubation is standard for treating severe traumatic brain injury (TBI). Aeromedical crews and select paramedic agencies use rapid sequence intubation (RSI) to facilitate intubation after TBI, with Glasgow Coma Scale (GCS) score commonly used as a screening tool. To explore the association between paramedic GCS and outcome in patients with TBI undergoing prehospital RSI, paramedics prospectively enrolled adult major trauma victims with GCS 3-8 and clinical suspicion for head trauma to undergo succinylcholine-assisted intubation as part of the San Diego Paramedic RSI Trial. The following data were abstracted from paramedic debriefing interviews and the county trauma registry: demographics, mechanism, vital signs including GCS score, clinical evidence of aspiration before RSI, arrival laboratory values, hospital course, and outcome. Paramedic GCS calculations were confirmed during debriefing interviews. Patients were stratified by GCS score, with chi-square and receiver-operator-curve (ROC) analysis used to explore the relationship between GCS and hypoxia, head injury severity, aspiration, intensive care unit (ICU) length of stay, and outcome. Cohort analysis was used to explore potential reasons for early extubation and discharge from the ICU in some patients. A total of 412 patients were included in this analysis. A total of 81 patients (20%) were extubated and discharged from the ICU in 48 h or less; these patients had higher pre-RSI oxygen saturation (SaO(2)) values and higher arrival serum ethanol levels. Paramedic and physician GCS calculations had high agreement (kappa=0.995). A statistically significant relationship was observed between GCS score and Head Abbreviated Injury Score (AIS), survival, and pre-RSI SaO(2) values. However, ROC analysis revealed a limited ability of GCS to predict the presence of severe TBI, injury severity, desaturation, aspiration, ICU length of stay, or ultimate survival. In conclusion, paramedics seem to accurately calculate GCS values before prehospital RSI. Although a relationship between paramedic GCS and outcome exists, the ability to predict the severity of injury, airway-related complications, ICU length of stay, and overall survival is limited using this single variable. Other factors should be considered to screen TBI patients for prehospital RSI.

Escala de Coma de Glasgow: subestimação em pacientes com respostas verbais impedidas

Questão freqüente no uso da Escala de Coma de Glasgow (ECGl), na fase aguda, em pacientes internados devido ao trauma crânio-encefálico (TCE) é a subestimação decorrente de situações impeditivas como intubação endotraqueal/traqueostomia, sedação e edema palpebral. O objetivo deste estudo foi identificar e determinar a subestimação na pontuação total da ECGl quando se utiliza a pontuação 1 nas situações de impedimento para a sua avaliação. A amostra estudada foi de 76 pacientes internados com TCE no Hospital das Clínicas da FMUSP. Em 42 (55,3%) pacientes, não havia impedimentos e foram realizadas 136 avaliações. Em 34 (44,7%), havia impedimentos caracterizados por intubação ou traqueostomia, podendo estar ou não associados com edema palpebral e sedação, e o total de avaliações foi de 310. A pontuação nesses pacientes total variou de 3 a 11, com os escores mais freqüentes de 3 e 6. Pelos valores estimados pela regressão linear, a partir das pontuações obtidas em AO e MRM foram obtidas as seguintes subestimações: média=1,03 ±1,36, mediana=0,54 (intubação ou traqueostomia); média=0,40 ±0,79, mediana=0,00 (intubação ou traqueostomia + sedação); média=0,57 ±0,96, mediana=0,27 (intubação ou traqueostomia + sedação + edema palpebral). Conclui-se que, no TCE grave, a pontuação total da ECGl fixando a MRV em 1, embora subestimada, encontra-se próxima da real.

A comparison of the Glasgow Coma Scale score to simplified alternative scores for the prediction of traumatic brain injury outcomes

STUDY OBJECTIVE

The 15-point Glasgow Coma Scale (GCS) is extensively used in the initial evaluation of traumatic brain injury in emergency department (ED) settings. We hypothesized that the GCS might be unnecessarily complex and that a simpler scoring system might demonstrate similar accuracy in the prediction of traumatic brain injury outcomes.

METHODS

We analyzed a prospectively maintained trauma registry of patients evaluated at our Level I trauma center from 1990 to 2002. We calculated the test performance of ED GCS scores relative to 4 clinically relevant traumatic brain injury outcomes (emergency intubation, neurosurgical intervention, brain injury, and mortality) using areas under their receiver operating characteristic (ROC) curves. We performed similar analyses for each of the 3 GCS components and for 2 simplified 3-point scores (simplified verbal score: oriented=2, confused conversation=1, inappropriate words or less=0; simplified motor score: obeys commands=2, localizes pain=1, withdrawal to pain or less=0). We then compared the test performance of each of these 5 to the total GCS score using a priori thresholds for clinically important differences.

RESULTS

Each of the 3 GCS components alone and the 2 simplified 3-point scores demonstrated ROC areas within 9% of that of the GCS score for the 4 outcomes, with a median difference of 3.0% (interquartile range 1.6% to 4.5%). These differences were all below our a priori definitions of clinical importance.

CONCLUSION

The 3 individual GCS components alone and two 3-point simplified scores demonstrated test performance similar to the total GCS score for the prediction of 4 clinically relevant traumatic brain injury outcomes. Despite the widespread use of the GCS for the initial evaluation of traumatic brain injury, this score may be unnecessarily complex for this indication.

A Comparison Among the Abilities of Various Injury Severity Measures to Predict Mortality With and Without Accompanying Physiologic Information

BACKGROUND

A few recent studies have compared the abilities of different injury severity measures to predict inpatient mortality. This study extended previous studies in that it used a registry with noncenters as well as centers, and examined the relative marginal abilities of competing severity measures to predict mortality when physiologic data also are available.

METHODS

Several methods for assessing injury severity of trauma patients were compared in terms of their ability to predict mortality with and without the addition of additional demographic and physiologic information using logistic regression models. Separate determinations also were made for all patients and for three groups of patients with blunt trauma resulting from motor vehicle crashes, low falls, and other blunt injuries. Statistical models were compared using measures of discrimination and calibration.

RESULTS

The International Classification of Disease-Based Severity Score (ICISS) had the best discrimination for each of the eight models examined, and it was significantly better than all the other measures in relation to the models for all patients and for victims of motor vehicle crashes. The ICISS also had the best calibration in half of the models with and half without demographic and physiologic information. The New Injury Severity Score had the best calibration in relation to two of the remaining four models. Physiologic data add substantially to the ability to predict mortality regardless of the anatomic injury severity measure used.

CONCLUSIONS

On the average, the ICISS had the best discrimination of all of the measures, as well as a slight edge with respect to calibration in predicting trauma mortality with or without the aid of demographic or physiologic measures.

Interrater reliability of Glasgow Coma Scale scores in the emergency department

STUDY OBJECTIVE

Emergency physicians often use the Glasgow Coma Scale (GCS) to help guide decisions in patient care, yet the reliability of the GCS has never been tested in a typical broad sample of emergency department (ED) patients. We determined the interrater reliability of the GCS between emergency physicians when adult patients with altered levels of consciousness are assessed.

METHODS

In this prospective observational study at a university Level I trauma center, we enrolled a convenience sample of ED patients older than 17 years who presented with an altered level of consciousness. Two residency-trained attending emergency physicians independently assessed and recorded the GCS score and its components (eye, verbal, and motor) in blinded fashion within a 5-minute period. Data were analyzed for interrater reliability by using standard ordinal calculations. We also created scatter plots and Bland-Altman plots for each GCS component and for the GCS score.

RESULTS

One hundred thirty-one patients were screened and enrolled in the study, with 15 excluded because of protocol violations. Of the 116 remaining patients, the agreement percentage for exact total GCS was 32% (tau-b=0.739; Spearman rho=0.864; Spearman rho2=75%). Agreement percentage for GCS components were eye 74% (tau-b=0.715; Spearman rho=0.757; Spearman rho2=57%), verbal 55% (tau-b=0.587; Spearman rho=0.665; Spearman rho2=44%), and motor 72% (tau-b=0.742; Spearman rho=0.808; Spearman rho2=65%). Our Spearman's analyses found that only approximately half (44% to 65%) of the observed variance could be explained by the relationship between the paired component measures. For GCS components, only 55% to 74% of paired measures were identical, and 6% to 17% of them were 2 or more points apart.

CONCLUSION

We found only moderate degrees of interrater agreement for the GCS and its components.

Elderly Trauma Inpatients in New York State: 1994???1998

BACKGROUND

The aging of the population in the United States has led to an increase in geriatric trauma. This study aimed to examine the characteristics and outcomes of geriatric trauma patients in New York State.

METHODS

Four groups of elderly trauma patients (ages 40-64, 65-74, 75-84, and 85+ years) were contrasted with younger adults ages 13 to 39 years with respect to mechanism of injury, discharge disposition, hospital length of stay, comorbidities, and type of hospital in which they were treated. Also, the independent association of each group with in-hospital mortality was investigated for patients with blunt injuries using logistic regression.

RESULTS

There was a 17.6% increase between 1994 and 1998 in the number of traumatic injuries qualifying for the New York State Trauma Registry in the 75- to 84-year-old group and a 16.4% increase in the group ages 85 years or older, despite a decrease in traumatic injuries in other age groups. The majority of these injuries among the patients 75 years of age or older resulted from low falls (from the same level). The mortality rate rose substantially with age, from 5.1% to 5.9% to 9.4% to 12.3% to 15.8%, respectively, for the groups ages 13 to 39, 40 to 64, 65 to 74, 75 to 84, and 85 or more years. Also, fewer than 20% of the patients older than 75 years died within 1 day after admission to the hospital, as compared with 44% of the patients younger than 65 years. The groups ages 40 to 64, 65 to 74, 75 to 84, and 85 years or older were all independent (increasingly) significant predictors of mortality for all three mechanisms of injury investigated. The adjusted odds ratios for mortality relative to patients who were 13 to 39 years of age were 2.67, 8.41, 17.40, and 34.98, respectively, for the groups ages 40 to 64, 65 to 74, 75 to 84, and 85 years or older.

CONCLUSIONS

Trauma is a serious and escalating problem for the elderly, and increasing age is a significant risk factor for patient mortality.

Severity of injury and mortality associated with pediatric blunt injuries: hospitals with pediatric intensive care units versus other hospitals

OBJECTIVE

To a) compare in-hospital mortality rates for pediatric (age <13 yrs) patients with blunt injuries in the New York State Trauma Registry based on hospital type (dedicated pediatric intensive care unit [PICU] and designated trauma centers and noncenters that do not have a dedicated PICU) for the purpose of determining whether there is a reduction in mortality at a specialty hospital and b) determine the extent to which high-risk patients are admitted to specialty hospitals.

DATA SOURCE

Inpatient data for the years 1994-1998 in the New York State Trauma Registry.

STUDY SELECTION

A total of 8,180 pediatric inpatients who suffered blunt injury were selected to examine where patients were treated (PICU, regional trauma center without PICU, area trauma center without PICU, or noncenter without PICU) as a function of injury severity.

DATA EXTRACTION

Data were extracted for inpatients aged <13 yrs who suffered blunt injury.

DATA SYNTHESIS

The injury severity of inpatients treated at PICUs and regional centers without PICUs was significantly higher than at other hospitals. Risk factors that were independently related to survival of pediatric trauma inpatients were age <5 yrs, motor component of one to five, abnormal systolic blood pressure relative to age, and International Classification of Disease, Ninth Revision-Based Injury Severity Score. Of the total 136 deaths, 133 were among the patients <5 yrs old, motor score <6, and age-related abnormal systolic blood pressure. A total of 66.8% of these patients were treated at PICUs, and 9.9% were treated at regional centers without PICUs. No statistically significant differences in risk-adjusted mortality rates were found by hospital type, but rates at PICUs were lower than for other types of hospitals except for noncenters without PICUs, whose patients were considerably less severely injured.

CONCLUSIONS

There is significant triaging of the most seriously injured pediatric trauma inpatients to PICUs, and there is evidence that this policy is effective.

Development and prospective validation of a model for predicting weaning in chronic ventilator dependent patients

BACKGROUND

Approximately ten percent of patients placed on mechanical ventilation during acute illness will require long-term ventilator support. Unfortunately, despite rehabilitation, some will never be liberated from the ventilator. A method of predicting weaning outcomes for these patients could help conserve resources and minimize frustrating failed weaning attempts for this population. The objective of this investigation was to identify predictors of weaning outcome for patients admitted to a chronic ventilator unit (CVU).

METHODS

This was a retrospective analysis with prospective validation. The study setting was a 25 bed CVU within a rehabilitation hospital. The training group consisted of 43 patients referred to our facility for weaning after > 3 weeks of mechanical ventilation. A multivariate model to predict weaning outcome was constructed in this group and applied to a prospective group of 31 patients followed during an 18-month period.

RESULTS

A modified Glasgow Coma Scale (GCS) and the presence of sustained spontaneous respirations (SSR), defined as the presence of 2 breaths recorded above the ventilator settings on four occasions, were highly predictive of weaning success within six months of CVU admission. Patients with a modified GCS > or = 8 were 6.5 times more likely to wean than those with a modified GCS < 8 (95% confidence interval 1.6-26.3) and those with SSR were 25.5 times more likely to wean than those without SSR (95% confidence interval 4.3-51.9).

CONCLUSIONS

In our population of CVU patients, simple parameters that were available on admission and did not directly reflect cardiopulmonary function were useful predictors of weaning outcome.

The status of the Glasgow Coma Scale

The Glasgow Coma Scale (GCS) was first introduced in the 1970s to provide a simple and reliable method of recording and monitoring change in the level of consciousness of head injured patients. Since its introduction, the GCS has been widely utilized in the trauma community and its use expanded beyond the original intentions of the score. In the context of traumatic injury, this paper discusses the use of the GCS as a predictor of outcome, the limitations of the GCS, the reliability of the GCS and potential alternatives through a critical review of the literature. The relevance to Australian trauma populations is also addressed.

A new "TRISS-like" probability of survival model for intubated trauma patients

BACKGROUND

Prehospital trauma patient field intubations and paralyzations, using neuromuscular blocking agents before emergency department respiratory and neurologic assessments are made, bias assessments and outcome evaluations using probability-of-survival models, such as TRISS and A Severity Characterization of Trauma (ASCOT). We present a newly developed "TRISS-like" probability-of-survival model for intubated blunt- and penetrating-injured patient assessment.

METHODS

From a population of 51397 consecutively admitted trauma patients, this study used all 5740 (11.2% of the total injured population) intubated patients with complete data from a statewide trauma registry from October 1, 1993, to September 30, 1996. Model performance was evaluated using standard calibration and discrimination measures and z and W statistics of significance.

RESULTS

The new model accurately predicted survival for blunt- and penetrating-injured intubated patients and is applicable to 11 etiologic patient populations.

CONCLUSION

Study findings suggest that the new TRISS-like model should be used to assess both blunt- and penetrating-injured intubated patients. Use of this new model provides an analytical method for addressing a significant limitation of both the standard TRISS and ASCOT models, which are not applicable to intubated injured patient assessment. In addition, use of this model will complement TRISS/ASCOT assessments of nonintubated trauma patients and thus permit appropriate assessments for both intubated and nonintubated injured patient study populations.

Improving the Glasgow Coma Scale score: motor score alone is a better predictor

BACKGROUND

The Glasgow Coma Scale (GCS) has served as an assessment tool in head trauma and as a measure of physiologic derangement in outcome models (e.g., TRISS and Acute Physiology and Chronic Health Evaluation), but it has not been rigorously examined as a predictor of outcome.

METHODS

Using a large trauma data set (National Trauma Data Bank, N = 204,181), we compared the predictive power (pseudo R2, receiver operating characteristic [ROC]) and calibration of the GCS to its components.

RESULTS

The GCS is actually a collection of 120 different combinations of its 3 predictors grouped into 12 different scores by simple addition (motor [m] + verbal [v] + eye [e] = GCS score). Problematically, different combinations summing to a single GCS score may actually have very different mortalities. For example, the GCS score of 4 can represent any of three mve combinations: 2/1/1 (survival = 0.52), 1/2/1 (survival = 0.73), or 1/1/2 (survival = 0.81). In addition, the relationship between GCS score and survival is not linear, and furthermore, a logistic model based on GCS score is poorly calibrated even after fractional polynomial transformation. The m component of the GCS, by contrast, is not only linearly related to survival, but preserves almost all the predictive power of the GCS (ROC(GCS) = 0.89, ROC(m) = 0.87; pseudo R2(GCS) = 0.42, pseudo R2(m) = 0.40) and has a better calibrated logistic model.

CONCLUSION

Because the motor component of the GCS contains virtually all the information of the GCS itself, can be measured in intubated patients, and is much better behaved statistically than the GCS, we believe that the motor component of the GCS should replace the GCS in outcome prediction models. Because the m component is nonlinear in the log odds of survival, however, it should be mathematically transformed before its inclusion in broader outcome prediction models.

Motor vehicle crashes in New York State: importance of accounting for emergency department deaths when assessing differences in in-hospital mortality by level of care

BACKGROUND

Motor vehicle crashes (MVCs) are one of the leading causes of death in the nation and in New York State, particularly among younger adult males. It is important to study how to reduce mortality from MVCs.

METHODS

Hospitalized victims of motor vehicle crashes in the 1994-1995 New York State Trauma Registry were identified for the study. A statistical model was used to calculate risk-adjusted mortality rates for groups of hospitals constituting each level of care (regional trauma center, area trauma center, noncenter). Levels of care were also compared with respect to the location of deaths in the hospital (emergency department, inpatient), and the time between emergency department admission and death for patients dying in the hospital.

RESULTS

The risk-adjusted mortality rate for MVCs in patients in regional centers was higher, although not significantly higher (6.91%; 95% confidence interval [CI], 6.18%-7.70%) than for area centers (5.53%; 95% CI, 4.43%-6.82%) or for noncenters (5.83%; 95% CI, 4.70%-7.15%). However, regional centers admitted seriously injured trauma patients from the emergency department much more quickly than other levels of care. Whereas only 18% of all in-hospital deaths occurred in emergency departments of regional centers, the comparable percentages for area centers and noncenters were 39% and 46%, respectively. Also, 43% of all deaths in regional centers occurred within 24 hours of presentation to the emergency department, compared with 15% in area centers and 21% in noncenters.

CONCLUSION

Risk-adjusted inpatient mortality rates for victims of MVCs may not yield a fair comparison of performance for different levels of care or for different hospitals because of differences in how quickly emergency department patients are admitted to the hospital. A more equitable way to assess hospital mortality rates may be to include emergency department deaths in addition to inpatient deaths.

Scoring systems in trauma

BACKGROUND

Trauma is a major cause of mortality and morbidity worldwide. Methods of assessing outcome have evolved with management of trauma victims.

RESULTS AND DISCUSSION

The wide variety of scoring instruments available to assess the injured patient may be divided into three groups: anatomical, physiological and combined systems. Anatomical systems depend on an accurate description of the injuries sustained. Physiological systems measure the effects of injury on the patient's physiological reserves. Combined systems contain elements of both anatomical and physiological scores. Prospectively, scoring systems help in description, triage, treatment decisions and estimating outcome. Retrospective scoring is helpful in audit, in quality control, in comparing treatment methods or centres, and in identifying unexpected outcomes. Limitations may be inherent in the system or may reflect inaccurate or incomplete data collection.

Predicting inpatient mortality for pediatric trauma patients with blunt injuries: a better alternative

PURPOSE

The aim of this study was to identify significant independent predictors of inpatient mortality rates for pediatric victims of blunt trauma and to develop a formula for predicting the probability of inpatient mortality for these patients.

METHODS

Emergency department and inpatient data from 2,923 pediatric victims of blunt injury in the New York State Trauma Registry in 1994 and 1995 were used to explore the relationship between patient risk factors and mortality rate. A stepwise logistic regression model with P<.05 was developed using survival status asthe dependent variable. Independent variables included are elements of the Pediatric Trauma Score (PTS), additional elements from the Revised Trauma Score (RTS), the motor response and eye opening components of the Glasgow Coma Scale (GCS), age-specific systolic blood pressure, the AVPU score, and 2 measures of anatomic injury severity (the Injury Severity Score [ISS] and the International Classification of Disease, Ninth Revision-based Injury Severity Score [ICISS]).

RESULTS

The only significant independent predictors of severity that emerged were the ICISS, no motor response (best motor response = 1) from the GCS, and the unresponsive component from the AVPU score. The statistical model exhibited an excellent fit (C statistic = .964). The specificity associated with the prediction of inpatient mortality rate based on the presence of 1 or more of these risk factors was .926, and the sensitivity was .944.

CONCLUSION

The best independent predictors of inpatient mortality rate for pediatric trauma patients with blunt injuries include variables not specifically contained in the PTS or the RTS: ICISS, no motor response (best motor response = 1) from the GCS, and the unresponsive component of the AVPU score.

An examination of the volume-mortality relationship for New York State trauma centers

OBJECTIVES

New York State Trauma Registry data were analyzed to determine whether there is a significant relationship between the volume of trauma patients treated by a trauma center and its risk-adjusted inpatient mortality rate.

METHODS

Stepwise logistic regression was used to identify significant independent predictors of mortality, their weights, and the probability of in-hospital mortality for each patient. These data were then used to calculate risk-adjusted mortality rates for various ranges of hospital volume. Ranges were identified on the basis of homogeneity of mortality rates, the number of hospitals in each range, and the number of patients in each range. Three volume measures were used: (1) total annual volume of trauma cases > or = 1200 and total annual volume > or = 240 for patients with Injury Severity Score (ISS) > or = 15 (equivalent to American College of Surgeons [ACS] criteria), (2) total annual volume of patients with ISS > or = 15, and (3) total annual volume of cases in the Registry (approximately, inpatients with ISS > or = 9).

RESULTS

Results show that the 35 New York State trauma centers not meeting the ACS criteria had lower, but not significantly lower, observed and risk-adjusted mortality rates (7.62% and 8.25%, respectively) than the corresponding rates for the 8 New York State trauma centers that met the ACS criteria (9.36% and 8.83%, respectively). Regarding the other two criteria, hospital ranges representing lower annual volumes tended to have somewhat lower, although not significantly lower, observed and risk-adjusted mortality rates. For example, using a total annual volume for patients with ISS > or = 15, the risk-adjusted mortality rates for the volume ranges 1-150, 151-250, and 251+ were 7.78%, 9.23%, and 8.70%, respectively.

CONCLUSIONS

We were unable to document an inverse relationship between hospital volume and inpatient mortality rate for trauma centers in New York State. Volume criteria should not be considered indicators of the quality of trauma care.

Accounting for intubation status in predicting mortality for victims of motor vehicle crashes

BACKGROUND

Two of the important predictors of mortality for trauma patients are the Glasgow Coma Scale and the respiratory rate. However, for intubated patients, the verbal response component of the Glasgow Coma Scale and the respiratory rate cannot be accurately obtained. This study extends previous work that attempts to predict mortality accurately for intubated patients without using verbal response and respiratory rate.

METHODS

The New York State Trauma Registry was used to identify 1994 and 1995 victims of motor vehicle crashes (MVCs). For the subset of patients who were not intubated, we developed two statistical models to predict mortality: one did not contain verbal response or respiratory rate, and the other contained a predicted verbal response. These were compared with a model that did include verbal response and respiratory rate. We also compared the predictive abilities of the first two models for all MVC patients (intubated and nonintubated) and determined the extent to which intubated patients were at increased risk of dying in the hospital after having adjusted for other predictors of mortality.

RESULTS

For nonintubated patients, the statistical model without verbal response and the model with predicted verbal response had slightly better discrimination and worse calibration than the model that included verbal response and respiratory rate. Predicted verbal response did not improve the strength of the model without verbal response. For all MVC patients (intubated and nonintubated), predicted verbal response was not a significant predictor of mortality when used in combination with the other predictors. Intubation status was a significant predictor, with intubated patients having a higher probability of dying in the hospital than patients with otherwise identical risk factors.

CONCLUSION

Inpatient mortality for intubated MVC patients can be accurately predicted without respiratory rate or verbal response. There appears to be no need for predicted verbal response to be part of the prediction formula, but intubation status is an important independent predictor of mortality and should be used in statistical models that predict mortality for MVC patients.

Variation among trauma centers' calculation of Glasgow Coma Scale score: results of a national survey

BACKGROUND

Glasgow Coma Scale (GCS) scoring is enigmatic in intubated patients. To determine if there is consensus among Level I trauma centers, a national telephone survey was conducted.

METHODS

Trauma registrars at state-verified or American College of Surgeons-verified Level I trauma centers were questioned about GCS scoring, recording, and reporting in patients who are intubated or intubated and pharmacologically paralyzed.

RESULTS

Seventy-three centers were contacted. Seventy-one use initial GCS scores for registry recording. Intubated patients are given 1 point for verbal component plus eye and motor scores at 26% of centers and a total GCS score of 3 at 23%; GCS score is estimated with "T" given for verbal component at 16%, scored as unknown at 10%, always scored as 15 at 10%, and the method of scoring is unknown at 15%. Pharmacologically paralyzed intubated patients are given a total GCS score of 3 at 34%, GCS score is estimated with "T" given for verbal component at 18%, patients are given 1 point for verbal component plus eye and motor scores at 12%, scored as unknown at 11%, always scored as 15 at 8%, and the method of scoring is unknown at 16%.

CONCLUSION

Wide variation in GCS scoring among Level I trauma centers was identified. Because GCS scores are used in treatment algorithms, trauma scoring, and outcome prediction (Trauma and Injury Severity Score), uniform scoring is essential and should be pursued. Use of state and national databases and outcome research may be adversely affected by the lack of consistent GCS scoring.

The conundrum of the Glasgow Coma Scale in intubated patients: a linear regression prediction of the Glasgow verbal score from the Glasgow eye and motor scores

BACKGROUND

The Glasgow Coma Scale (GCS), which is the foundation of the Trauma Score, Trauma and Injury Severity Score, and the Acute Physiology and Chronic Health Evaluation scoring systems, requires a verbal response. In some series, up to 50% of injured patients must be excluded from analysis because of lack of a verbal component for the GCS. The present study extends previous work evaluating derivation of the verbal score from the eye and motor components of the GCS.

METHODS

Data were obtained from a state trauma registry for 24,565 unintubated patients. The eye and motor scores were used in a previously published regression model to predict the verbal score: Derived Verbal Score = -0.3756 + Motor Score * (0.5713) + Eye Score * (0.4233). The correlation of the actual and derived verbal and GCS scales were assessed. In addition the ability of the actual and derived GCS to predict patient survival in a logistic regression model were analyzed using the PC SAS system for statistical analysis. The predictive power of the actual and the predicted GCS were compared using the area under the receiver operator characteristic curve and Hosmer-Lemeshow goodness-of-fit testing.

RESULTS

A total of 24,085 patients were available for analysis. The mean actual verbal score was 4.4 +/- 1.3 versus a predicted verbal score of 4.3 +/- 1.2 (r = 0.90, p = 0.0001). The actual GCS was 13.6 + 3.5 versus a predicted GCS of 13.7 +/- 3.4 (r = 0.97, p = 0.0001). The results of the comparison of the prediction of survival in patients based on the actual GCS and the derived GCS show that the mean actual GCS was 13.5 + 3.5 versus 13.7 + 3.4 in the regression predicted model. The area under the receiver operator characteristic curve for predicting survival of the two values was similar at 0.868 for the actual GCS compared with 0.850 for the predicted GCS.

CONCLUSIONS

The previously derived method of calculating the verbal score from the eye and motor scores is an excellent predictor of the actual verbal score. Furthermore, the derived GCS performed better than the actual GCS by several measures. The present study confirms previous work that a very accurate GCS can be derived in the absence of the verbal component.