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Abbreviated injury scaling of head injury as a prognostic tool for functional outcome
Acrid. Anal. & Prev. Vol. 24. No. 2. pp. 181-185, 1992 Printed in Great Britain.
Oooi-4575192 SUN+ .W 8 1992 Pergamon Press Ltd.
ABBREVIATED INJURY SCALING OF HEAD INJURY AS A PROGNOSTIC TOOL FOR FUNCTIONAL OUTCOME* STEVEN E. Ross, KEITH E O'MALLEY, and SHERMAN STEIN Department
of Surgery, University of Medicine and Dentistry of New Jersey/Robert Johnson Medical School, Camden, NJ 08103 U.S.A.
CLAIRE M. SPETTELL Institute of Brain Injury Research and Training, Mediplex Rehab-Camden, NJ 08103. U.S.A.
Wood
Camden,
and
GARY YOUNG Cooper Hospital/University
Medical Center, Camden, NJ 08103, U.S.A.
(Received
17 Augusi
1990)
Abstract-The use of Abbreviated Injury Scaling for the head region (HAIS) was evaluated as a prognostic index of functional outcome in 503 consecutive patients with severe injury to the brain who survived initial resuscitation. Although a strong statisticai reiationship between HAIS and outcome as measured by the Glasgow Outcome Scale was demonstrated, its clinical usefulness is limited. HAIS may be most useful as a classifier for comparative studies of populations and for the evaluation of therapeutic modalities.
Patients who survive severe brain injury are likely to suffer permanent behavioral, cognitive, and psychosocial impairment of varying magnitude, which may significantly limit their capacity to function in society. The ability to predict functional outcome early in the course of treatment following closed head injury would be invaluable in family counselling, hospital resource allocation, and cost projection. In addition, definition of the relationship between severity of initial injury and functional outcome is required for objective comparison of populations undergoing different treatment regimens. Although various scaling systems and clinical parameters have been shown to correlate with mortality following severe brain injury (Choi et al. 1983; Jennett and Bond 1975; Lobato et al. 1983; Young et al. 1981), the early prediction of functional outcome remains problematic. In order to examine the value of early clinical scaling of head injury, using the Abbreviated Injury Scale (Committee on Injury Scaling 1985) for this purpose, a study of all patients admitted to a Level I trauma center with severe closed head injury was undertaken. MATERIALS
AND
METHODS
All patients admitted to the Southern New Jersey Regional Trauma Center between January 1, 1986 and December 31, 1988 were evaluated and resuscitated under the protocols of the center. This included emergent endotracheal intubation, hyperventilation, and computerized tomography (CT) of the brain, in all cases with suspected brain injury as evidenced by depressed level of consciousness or focal neurologic signs on admission to the trauma center. Abbreviated Injury Scaling (AIS) was performed and Injury Severity Score (ISS) (Baker et al. 1974) calculated within 48 hours of admission using early clinical scoring methodology (Civil et al. 1987). Results of serial CT scanning of the brain, as well as hourly neurologic examination during the first 48 hours of *Presented at the 34th Annual Meeting of the Association for the Advancement of Automotive Medicine, October l-3, 1990, Scottsdale, AZ. 181
S. E. Ross et al.
182
hospitalization were used as the basis for clinical AIS scaling. Demographic and prehospital data, admission physiologic parameters, and results of initial laboratory and radiographic examinations were recorded in a computerized registry on each patient. Glasgow Coma Score (GCS) (Teasdale and Jennett 3974), a 13-point scaling system for level of consciousness (range 3-15). involving the patient’s ocular, verbal, and motor responses to stimuli, and Trauma Score (TS) (Champion et al. 1981), a 15-point scale of physiologic response to injury (range l-16), were also recorded upon hospital admission. All patients suffering nonpenetrating brain injury with an HAIS of 3 or greater, or those with an HAIS of 2 and admission GCS less than i3 were selected for inclusion in the study. Those who died prior to completion of resuscitation or emergent surgery were excluded from statistical analysis of functional outcome. Functional outcome was graded using the Glasgow Outcome Score (GOS) (Jennett et al. 1979). This scale classifies outcome into five categories: (i) death; (ii) persistent vegetative state; (iii) severe disability; (iv) moderate disability; and; (v) good recovery. Late follow-up was obtained through outpatient office visits, patient records from rehabilitation centers. and from the patients or their families. In those cases involving inpatient or outpatient rehabilitation. the GOS was assigned by a staff physiatrist or psychologist. For patients not requiring rehabilitative intervention, the GOS was determined by a traumatologist or neurosurgeon. All outcome scores were assigned at least six months after injury. All data were entered in a single computerized data base (dBase III plus@‘, AshtonTate, Torrance, CA, U.S.A.). Statistical analysis was carried out using computerized statistical software (dBase Stats=, Ashton-Tate, Torrance, CA, U.S.A. and Systatm, Systat Inc.. Evanston, IL, U.S.A.). A log-linear analysis of the contingency table was employed. Given the ordinal nature of both scales, Spearman rank order correlation was performed to evaluate the correlation between HAIS and GOS. Linear regression was performed in order to inspect the residuals and to determine correlation coefficients (R) for comparison purposes. RESULTS
Five hundred ninety-one patients suffering severe closed head injury following blunt trauma were admitted to the trauma service during the three-year period under study. There were 425 males (7270) in this population. The mean age was 28 and the age distribution is summarized in Table 1. Mean TS and GCS on admission were 11 and 8, respectively, and 461 (78%) patients presented with a GCS less than 13. One hundred sixteen patients received cardiopulmonary resuscitation (CPR) prior to hospital arrival. Four hundred five (68.5%) had an ISS greater than 15. and 286 (48.4/)*O sustained at least one extracranial system injury with AIS score of 3 or greater. Mechanisms of injury are summarized in Table 2. Follow-up was unavailable on 39 patients (6.6%) and these were excluded from analysis. There were 147 deaths (24.9%) during the minimum six-month follow-up period. Thirty eight of these patients expired during initial resuscitation. and 11 died during emergent operation. and these were also excluded from further analysis. Data regarding
Age range
(years)
O-IO I l-20 2 I-30 3 l-40 41-X) 5 l-60 61-70 170
Number 77 139 170 97 40 27 22 19
(c/r)
(13.0) (23.5) 03.X) i16.4) (6.8) (3.6) (3.7) (3.2)
Abbreviated
Injury Scaling of head injury
183
Table 2. Mechanisms of iniury Mechanism
Number (%)
Motor vehicle crash Pedestrian-Motor vehicle crash Assaults Falls Bicycle crashes Motorcycle crashes Industrial mishaps Airplane
322 (54.5) 115 (19.5) 53 (9.0) 46 (7.8) 27 (4.5) 21 (3.5) 6 (1.0) 1 (0.2)
503 survivors of initial care, with follow-up as described above, were available for analysis. The breakdown of HAIS and GOS for these patients is shown in Table 3. There were 110 deaths among these patients, 98 during acute hospitalization and 12 following acute hospital discharge. All deaths in the HAIS- and HAIS- groups were due to extracranial causes, as were 10 of the 12 deaths in HAIS4; however, 63 (73%) of the deaths in HAIS- were directly related to brain injury. DATA
ANALYSIS
Contingency table analysis of Table 3 yielded a Chi-square value of 245.8, with 12 degrees of freedom; this is significant at 99.9% confidence limits. The number of empty cells in the table, however, limit the accuracy of this analysis. Log-linear table analysis, based on marginal distribution of cases, however, confirmed a significant relationship between HAIS and GOS in the hypothesised direction. The likelihood ratio Chi-squared value was 266.1 (p < .OOl), allowing us to reject our null hypothesis that HAIS and GOS were unrelated. The gamma and lambda statistics for this table were calculated in order to evaluate the strength of association of HAIS with GOS. Gamma was found to be -0.745, indicating a strong discordant relationship between HAIS and GOS; however, lambda was 0.29, indicating a low explicit predictive value for HAIS. Spearman’s rank correlation coefficient was - 0.617 (p 5 .02), indicating strong negative correlation between HAIS and GOS. Linear regression analysis was performed to determine correlation coefficient (R) for HAIS as predicting GOS. For the study population R = 0.63 (R squared = 0.39). For comparison purposes, similar analysis of initial GCS versus GOS yielded an R of 0.44 (R squared = 0.2). Addition of initial GCS to HAIS in a multiple regression analysis only improved R to 0.65 (R squared = 0.43). Examination of cases with high residual values revealed them to be patients who died with less severe (HAIS < 5) injuries, all due to extracranial injuries or complications. DISCUSSION
The relationship of acute physiologic and anatomic assessments of injury to mortality has been well established (Lobato et al. 1983; Teasdale and Jennett 1974; Young et al.
Table 3. Head injury severity vs functional outcome Glasgow Outcome Scale Head AIS
1
2
3
4
5
Total
2 3 4 5
1 11 12 86
0 0 2 14
0 11 2 17
7 31 17 15
79 128 49 21
87 181 82 153
110
16
30
70
277
503
Total
1x4
S. E. Ross et al.
1981). The value of these clinical scales in the prediction of functional outcome has not been determined. The development of quantitative measures of functional performance following closed head injury, using scales such as the GOS, allows a statistical evaluation of these relationships. Jennett (1979) asserted that the best GCS obtained in the first 24 hours following injury was predictive of outcome; however, other authors have indicated that the initial GCS may be equally valid, particularly if combined with anatomic data (Young et al. 1981). Others have been unable to demonstrate a relationship between GCS and functional outcome (Levati et al. 19K3). Our data indicate that this physiologic measure can account for only 20% of the observed variation in GOS in our population. Anatomy of injury has also been advanced as a predictor of functional outcome, with Lobato and associates (1983) and Narayan and others (1981) demonstrating its impact on outcome. The possible advantages of an anatomic scale as a means of ordinally grading injury to the brain, rather than using qualitative descriptions based on CT findings, have not yet been well investigated. Nygren and associates (1986) demonstrated permanent disability in 33% of survivors with AIS 5 head injury, with much lower rates among victims of AIS 3 or 4 severity. MacKenzie et al. (1987) found that head and spinal cord injuries resulted in the most significant disabilities and indicated that AIS scores of specific anatomic regions were more useful than the ISS in predicting functional deficit following multisystem trauma. Our data show similar differences. with HAIS alone accounting for neatly 40% of the variation in outcome in our study group. All the “outliers’” were those who died of causes not directly related to head injury. These data support the use of early anatomic injury severity sealing in the prediction of both mortality and functional outcome following severe brain injury, as evidenced by a strong statistical relationship between HAIS and GOS. In attempting to precisely predict outcome for an individual patient. Abbreviated Injury Scaling alone is insufficient to provide a satisfactory level of accuracy for clinical application, even when a broad classification scheme such as the Glasgow Outcome Scale is utilized. Previous work by Smejkal et al. (1989) have demonstrated that the early clinical method of AIS scaling may not be equivalent to the discharge diagnosis method. For HAIS, however, the physiologic component related to length of coma is more frequently identified clinically, resulting in more accurate HAIS scoring. Although the addition of other clinical measures, such as Glasgow Coma Scale may improve validity of prediction (Pal et al. 1989), our analyses indicate that this is unlikely to achieve the level necessary to reliably forecast outcome for an individual patient. Prognostic indicators of functional outcome following injury, particularly those involving the brain, are required for evaluation of treatment protocols, resource planning, and quality assurance, as well as for research purposes. The relationship between HAIS (as a combined surrogate for anatomic severity of injury and early physiologic status) and functional result, make this measure a useful tool for these purposes. Stratification of populations by HAIS should be useful in comparison of outcome based on different treatment protocols, as well as planning the needs for rehabilitation services in a given patient population. The challenge remains to identify indicators that will allow more accurate early prediction of ultimate outcome. REFERENCES Baker, S. P.; O’NeilI, B: Haddon. W. et al. The Injury Severity Score: A method of describing patients with multiple injuries and evaluating emergency care. J. Trauma 14:187-196: 1974. Champion, H. R.; Sacco. W. J.; Carnazzo. A. J. et al. Trauma score. Crit. Care Med. Y:h72-676; 1081. Choi. S. C.; Ward. J. D.; Becker, D. P. Chart for outcome prediction in severe head injury. J. Neurosurg. 59~294-297; 1983. Civil, I. D.; Kauder, D. R.; Schwab, C. W. Use of a single page scaling chart (AIS-85) in clinical practice. 31st Annual Proceedings, American Association for Automotive Medicine, New Orleans, Louisiana, September 1987. Committee on Injury Scaling. The Abbreviated Injury Scale (AIS) 1985 revision. Morton Grove, IL American Association for Automotive Medicine: 1985. Jennett. B; Bond. M. Assessment of outcome after severe brain damage. A practical scale. Lancet 1:480484; 1975.
Abbre~ated
Injury Scaling of head injury
185
Jennett, B.; Teasdale, G.; Braakman. R. et al. Prognosis of patients with severe head injury. Neurosurgery 4~283-289; 1979. Levati, A.; Farinal, M. L.; Vecchi, G. et al. Prognosis of severe head injuries. J. Neurosurg. 57:779-783; 1982. Lobato, R. D.; Cordobes, F.; Rivas, J. J. et al. Outcome from severe head injury related to the type of intracranial lesion. J. Neurosurg. 59:762-774; 1983. MacKenzie, E. J.; Shapiro. S.; Smith, R. T. et al. Factors influencing return to work following hospitalization for traumatic injury. Am. J. Public Health 77:329-334; 1987. Narayan, R. K.; Greenberg, R. P.; Miller, J. D. et al. Improved confidence of outcome prediction in severe head injury. J. Neurosurg. 54:751-762; 1981. Nygren, A.; Hansson, P. G.; Tingvall, C. Acute injury scaling related to residual disability. Acta Neurochir. (Suppl.) 36:25-27; 1986. Pal. J.; Brown, R.; Fieiszer, D. The value of Glasgow Coma Scale and Injury Severity Score: Predicting outcome in multiple trauma patients with head injury. J. Trauma 29:746-748; 1989. Smejkal, R.; Civil, I.; Unkle, D, et al. Injury severity scoring: A comparison of early clinical versus discharge diagnosis. Accid. Anal. Prev. 21:386-388; 1989. Teasdale, G.; Jennett, B. Assessment of coma and impaired consciousness: A practical scale. Lancet 2:8184; 1974. Young, B.; Rapp, R. P.; Norton, J. A. Early prediction of outcome in head-injured patients. J. Neurosurg. 54:300-303: 1981.
Oooi-4575192 SUN+ .W 8 1992 Pergamon Press Ltd.
ABBREVIATED INJURY SCALING OF HEAD INJURY AS A PROGNOSTIC TOOL FOR FUNCTIONAL OUTCOME* STEVEN E. Ross, KEITH E O'MALLEY, and SHERMAN STEIN Department
of Surgery, University of Medicine and Dentistry of New Jersey/Robert Johnson Medical School, Camden, NJ 08103 U.S.A.
CLAIRE M. SPETTELL Institute of Brain Injury Research and Training, Mediplex Rehab-Camden, NJ 08103. U.S.A.
Wood
Camden,
and
GARY YOUNG Cooper Hospital/University
Medical Center, Camden, NJ 08103, U.S.A.
(Received
17 Augusi
1990)
Abstract-The use of Abbreviated Injury Scaling for the head region (HAIS) was evaluated as a prognostic index of functional outcome in 503 consecutive patients with severe injury to the brain who survived initial resuscitation. Although a strong statisticai reiationship between HAIS and outcome as measured by the Glasgow Outcome Scale was demonstrated, its clinical usefulness is limited. HAIS may be most useful as a classifier for comparative studies of populations and for the evaluation of therapeutic modalities.
Patients who survive severe brain injury are likely to suffer permanent behavioral, cognitive, and psychosocial impairment of varying magnitude, which may significantly limit their capacity to function in society. The ability to predict functional outcome early in the course of treatment following closed head injury would be invaluable in family counselling, hospital resource allocation, and cost projection. In addition, definition of the relationship between severity of initial injury and functional outcome is required for objective comparison of populations undergoing different treatment regimens. Although various scaling systems and clinical parameters have been shown to correlate with mortality following severe brain injury (Choi et al. 1983; Jennett and Bond 1975; Lobato et al. 1983; Young et al. 1981), the early prediction of functional outcome remains problematic. In order to examine the value of early clinical scaling of head injury, using the Abbreviated Injury Scale (Committee on Injury Scaling 1985) for this purpose, a study of all patients admitted to a Level I trauma center with severe closed head injury was undertaken. MATERIALS
AND
METHODS
All patients admitted to the Southern New Jersey Regional Trauma Center between January 1, 1986 and December 31, 1988 were evaluated and resuscitated under the protocols of the center. This included emergent endotracheal intubation, hyperventilation, and computerized tomography (CT) of the brain, in all cases with suspected brain injury as evidenced by depressed level of consciousness or focal neurologic signs on admission to the trauma center. Abbreviated Injury Scaling (AIS) was performed and Injury Severity Score (ISS) (Baker et al. 1974) calculated within 48 hours of admission using early clinical scoring methodology (Civil et al. 1987). Results of serial CT scanning of the brain, as well as hourly neurologic examination during the first 48 hours of *Presented at the 34th Annual Meeting of the Association for the Advancement of Automotive Medicine, October l-3, 1990, Scottsdale, AZ. 181
S. E. Ross et al.
182
hospitalization were used as the basis for clinical AIS scaling. Demographic and prehospital data, admission physiologic parameters, and results of initial laboratory and radiographic examinations were recorded in a computerized registry on each patient. Glasgow Coma Score (GCS) (Teasdale and Jennett 3974), a 13-point scaling system for level of consciousness (range 3-15). involving the patient’s ocular, verbal, and motor responses to stimuli, and Trauma Score (TS) (Champion et al. 1981), a 15-point scale of physiologic response to injury (range l-16), were also recorded upon hospital admission. All patients suffering nonpenetrating brain injury with an HAIS of 3 or greater, or those with an HAIS of 2 and admission GCS less than i3 were selected for inclusion in the study. Those who died prior to completion of resuscitation or emergent surgery were excluded from statistical analysis of functional outcome. Functional outcome was graded using the Glasgow Outcome Score (GOS) (Jennett et al. 1979). This scale classifies outcome into five categories: (i) death; (ii) persistent vegetative state; (iii) severe disability; (iv) moderate disability; and; (v) good recovery. Late follow-up was obtained through outpatient office visits, patient records from rehabilitation centers. and from the patients or their families. In those cases involving inpatient or outpatient rehabilitation. the GOS was assigned by a staff physiatrist or psychologist. For patients not requiring rehabilitative intervention, the GOS was determined by a traumatologist or neurosurgeon. All outcome scores were assigned at least six months after injury. All data were entered in a single computerized data base (dBase III plus@‘, AshtonTate, Torrance, CA, U.S.A.). Statistical analysis was carried out using computerized statistical software (dBase Stats=, Ashton-Tate, Torrance, CA, U.S.A. and Systatm, Systat Inc.. Evanston, IL, U.S.A.). A log-linear analysis of the contingency table was employed. Given the ordinal nature of both scales, Spearman rank order correlation was performed to evaluate the correlation between HAIS and GOS. Linear regression was performed in order to inspect the residuals and to determine correlation coefficients (R) for comparison purposes. RESULTS
Five hundred ninety-one patients suffering severe closed head injury following blunt trauma were admitted to the trauma service during the three-year period under study. There were 425 males (7270) in this population. The mean age was 28 and the age distribution is summarized in Table 1. Mean TS and GCS on admission were 11 and 8, respectively, and 461 (78%) patients presented with a GCS less than 13. One hundred sixteen patients received cardiopulmonary resuscitation (CPR) prior to hospital arrival. Four hundred five (68.5%) had an ISS greater than 15. and 286 (48.4/)*O sustained at least one extracranial system injury with AIS score of 3 or greater. Mechanisms of injury are summarized in Table 2. Follow-up was unavailable on 39 patients (6.6%) and these were excluded from analysis. There were 147 deaths (24.9%) during the minimum six-month follow-up period. Thirty eight of these patients expired during initial resuscitation. and 11 died during emergent operation. and these were also excluded from further analysis. Data regarding
Age range
(years)
O-IO I l-20 2 I-30 3 l-40 41-X) 5 l-60 61-70 170
Number 77 139 170 97 40 27 22 19
(c/r)
(13.0) (23.5) 03.X) i16.4) (6.8) (3.6) (3.7) (3.2)
Abbreviated
Injury Scaling of head injury
183
Table 2. Mechanisms of iniury Mechanism
Number (%)
Motor vehicle crash Pedestrian-Motor vehicle crash Assaults Falls Bicycle crashes Motorcycle crashes Industrial mishaps Airplane
322 (54.5) 115 (19.5) 53 (9.0) 46 (7.8) 27 (4.5) 21 (3.5) 6 (1.0) 1 (0.2)
503 survivors of initial care, with follow-up as described above, were available for analysis. The breakdown of HAIS and GOS for these patients is shown in Table 3. There were 110 deaths among these patients, 98 during acute hospitalization and 12 following acute hospital discharge. All deaths in the HAIS- and HAIS- groups were due to extracranial causes, as were 10 of the 12 deaths in HAIS4; however, 63 (73%) of the deaths in HAIS- were directly related to brain injury. DATA
ANALYSIS
Contingency table analysis of Table 3 yielded a Chi-square value of 245.8, with 12 degrees of freedom; this is significant at 99.9% confidence limits. The number of empty cells in the table, however, limit the accuracy of this analysis. Log-linear table analysis, based on marginal distribution of cases, however, confirmed a significant relationship between HAIS and GOS in the hypothesised direction. The likelihood ratio Chi-squared value was 266.1 (p < .OOl), allowing us to reject our null hypothesis that HAIS and GOS were unrelated. The gamma and lambda statistics for this table were calculated in order to evaluate the strength of association of HAIS with GOS. Gamma was found to be -0.745, indicating a strong discordant relationship between HAIS and GOS; however, lambda was 0.29, indicating a low explicit predictive value for HAIS. Spearman’s rank correlation coefficient was - 0.617 (p 5 .02), indicating strong negative correlation between HAIS and GOS. Linear regression analysis was performed to determine correlation coefficient (R) for HAIS as predicting GOS. For the study population R = 0.63 (R squared = 0.39). For comparison purposes, similar analysis of initial GCS versus GOS yielded an R of 0.44 (R squared = 0.2). Addition of initial GCS to HAIS in a multiple regression analysis only improved R to 0.65 (R squared = 0.43). Examination of cases with high residual values revealed them to be patients who died with less severe (HAIS < 5) injuries, all due to extracranial injuries or complications. DISCUSSION
The relationship of acute physiologic and anatomic assessments of injury to mortality has been well established (Lobato et al. 1983; Teasdale and Jennett 1974; Young et al.
Table 3. Head injury severity vs functional outcome Glasgow Outcome Scale Head AIS
1
2
3
4
5
Total
2 3 4 5
1 11 12 86
0 0 2 14
0 11 2 17
7 31 17 15
79 128 49 21
87 181 82 153
110
16
30
70
277
503
Total
1x4
S. E. Ross et al.
1981). The value of these clinical scales in the prediction of functional outcome has not been determined. The development of quantitative measures of functional performance following closed head injury, using scales such as the GOS, allows a statistical evaluation of these relationships. Jennett (1979) asserted that the best GCS obtained in the first 24 hours following injury was predictive of outcome; however, other authors have indicated that the initial GCS may be equally valid, particularly if combined with anatomic data (Young et al. 1981). Others have been unable to demonstrate a relationship between GCS and functional outcome (Levati et al. 19K3). Our data indicate that this physiologic measure can account for only 20% of the observed variation in GOS in our population. Anatomy of injury has also been advanced as a predictor of functional outcome, with Lobato and associates (1983) and Narayan and others (1981) demonstrating its impact on outcome. The possible advantages of an anatomic scale as a means of ordinally grading injury to the brain, rather than using qualitative descriptions based on CT findings, have not yet been well investigated. Nygren and associates (1986) demonstrated permanent disability in 33% of survivors with AIS 5 head injury, with much lower rates among victims of AIS 3 or 4 severity. MacKenzie et al. (1987) found that head and spinal cord injuries resulted in the most significant disabilities and indicated that AIS scores of specific anatomic regions were more useful than the ISS in predicting functional deficit following multisystem trauma. Our data show similar differences. with HAIS alone accounting for neatly 40% of the variation in outcome in our study group. All the “outliers’” were those who died of causes not directly related to head injury. These data support the use of early anatomic injury severity sealing in the prediction of both mortality and functional outcome following severe brain injury, as evidenced by a strong statistical relationship between HAIS and GOS. In attempting to precisely predict outcome for an individual patient. Abbreviated Injury Scaling alone is insufficient to provide a satisfactory level of accuracy for clinical application, even when a broad classification scheme such as the Glasgow Outcome Scale is utilized. Previous work by Smejkal et al. (1989) have demonstrated that the early clinical method of AIS scaling may not be equivalent to the discharge diagnosis method. For HAIS, however, the physiologic component related to length of coma is more frequently identified clinically, resulting in more accurate HAIS scoring. Although the addition of other clinical measures, such as Glasgow Coma Scale may improve validity of prediction (Pal et al. 1989), our analyses indicate that this is unlikely to achieve the level necessary to reliably forecast outcome for an individual patient. Prognostic indicators of functional outcome following injury, particularly those involving the brain, are required for evaluation of treatment protocols, resource planning, and quality assurance, as well as for research purposes. The relationship between HAIS (as a combined surrogate for anatomic severity of injury and early physiologic status) and functional result, make this measure a useful tool for these purposes. Stratification of populations by HAIS should be useful in comparison of outcome based on different treatment protocols, as well as planning the needs for rehabilitation services in a given patient population. The challenge remains to identify indicators that will allow more accurate early prediction of ultimate outcome. REFERENCES Baker, S. P.; O’NeilI, B: Haddon. W. et al. The Injury Severity Score: A method of describing patients with multiple injuries and evaluating emergency care. J. Trauma 14:187-196: 1974. Champion, H. R.; Sacco. W. J.; Carnazzo. A. J. et al. Trauma score. Crit. Care Med. Y:h72-676; 1081. Choi. S. C.; Ward. J. D.; Becker, D. P. Chart for outcome prediction in severe head injury. J. Neurosurg. 59~294-297; 1983. Civil, I. D.; Kauder, D. R.; Schwab, C. W. Use of a single page scaling chart (AIS-85) in clinical practice. 31st Annual Proceedings, American Association for Automotive Medicine, New Orleans, Louisiana, September 1987. Committee on Injury Scaling. The Abbreviated Injury Scale (AIS) 1985 revision. Morton Grove, IL American Association for Automotive Medicine: 1985. Jennett. B; Bond. M. Assessment of outcome after severe brain damage. A practical scale. Lancet 1:480484; 1975.
Abbre~ated
Injury Scaling of head injury
185
Jennett, B.; Teasdale, G.; Braakman. R. et al. Prognosis of patients with severe head injury. Neurosurgery 4~283-289; 1979. Levati, A.; Farinal, M. L.; Vecchi, G. et al. Prognosis of severe head injuries. J. Neurosurg. 57:779-783; 1982. Lobato, R. D.; Cordobes, F.; Rivas, J. J. et al. Outcome from severe head injury related to the type of intracranial lesion. J. Neurosurg. 59:762-774; 1983. MacKenzie, E. J.; Shapiro. S.; Smith, R. T. et al. Factors influencing return to work following hospitalization for traumatic injury. Am. J. Public Health 77:329-334; 1987. Narayan, R. K.; Greenberg, R. P.; Miller, J. D. et al. Improved confidence of outcome prediction in severe head injury. J. Neurosurg. 54:751-762; 1981. Nygren, A.; Hansson, P. G.; Tingvall, C. Acute injury scaling related to residual disability. Acta Neurochir. (Suppl.) 36:25-27; 1986. Pal. J.; Brown, R.; Fieiszer, D. The value of Glasgow Coma Scale and Injury Severity Score: Predicting outcome in multiple trauma patients with head injury. J. Trauma 29:746-748; 1989. Smejkal, R.; Civil, I.; Unkle, D, et al. Injury severity scoring: A comparison of early clinical versus discharge diagnosis. Accid. Anal. Prev. 21:386-388; 1989. Teasdale, G.; Jennett, B. Assessment of coma and impaired consciousness: A practical scale. Lancet 2:8184; 1974. Young, B.; Rapp, R. P.; Norton, J. A. Early prediction of outcome in head-injured patients. J. Neurosurg. 54:300-303: 1981.