Subarachnoid versus Nonsubarachnoid Traumatic Brain Injuries: The Impact of Decision-Making on Patient Safety

Abstract

Introduction:

Traumatic intracranial hemorrhages (ICHs) are high priority injuries. Traumatic brain bleeds can be categorized as traumatic subarachnoid hemorrhage (SAH) versus non-SAH-ICH. Non-SAH-ICH includes subdural, epidural, and intraventricular hematomas and brain contusions. We hypothesize that awake patients with SAH will have lower mortality and needless interventions than awake patients with non-SAH-ICHs.

Study Design and Methods:

A review of data collected from our Level I trauma center was conducted. Awake was defined as an initial Glasgow coma score (GCS) 13–15. Patients were divided into two cohorts: awake SAH and awake non-SAH-ICH. Chi-square and t-test analyses were used with statistical significance defined as P < 0.05.

Results:

A total of 12,482 trauma patients were admitted during the study period, of which 225 had a SAH and GCS of 13–15 while 826 had a non-SAH-ICH with a GCS of 13–15. There was no significant difference in demographics between the two groups. Predicted survival between the two groups was similar (97.3 vs. 95.7%, P > 0.05). Mortality rates were, however, significantly lower in SAH patients compared to the non-SAH-ICH (4/225 [1.78%] vs. 22/826 [2.66%], P < 0.05). The need for neurosurgical intervention was significantly different comparing the SAH group versus non-SAH-ICH (2/225 [0.89%] vs. 100/826 [12.1%], P < 0.05).

Conclusion:

Despite similar predicted mortality rates, awake patients with a SAH are associated with a significantly lower risk of death and need for neurosurgical intervention when compared to other types of awake patients with a traumatic brain bleed.

INTRODUCTION

Trauma is the leading cause of death for individuals younger than 45 years old and the fourth leading cause of death overall for all ages.[1] Traumatic intracranial hemorrhages (ICHs) are high priority injuries, and patient outcomes from these severe injuries vary from full functionality to death.[2,3] These injuries demand special attention and medical expertise to be managed appropriately; not only are traumatic brain injuries (TBIs) the leading cause of death in those younger than 45, but also they are the overall leading cause of death and disability in trauma patients.[4] Previous studies have shown that nearly 50% of Level 1 trauma center patients who arrive with altered mental status have some type of ICH.[3,4,5] Trauma patients who present with traumatic ICHs have increased mortality when compared to those presenting without traumatic ICHs.[3,4,5] However, not all ICHs have similar outcomes; patient outcomes among traumatic ICHs correlate with the type, morphology, location of the ICH, and other associated injuries.[2,3,4,5,6] Most trauma surgeons and neurosurgeons share similar opinions on need for surgical intervention for some ICHs.[7] In the fields of trauma and neurosurgery, it is often stated that subarachnoid hemorrhages (SAHs) are the less life-threatening of the traumatic ICHs,[1,2,3,4,5] but this axiom has not been well studied. This review compares the mortality and the need for neurosurgical intervention between awake patients with a traumatic SAH and awake patients with other traumatic non-SAH-ICHs. The advanced trauma life support also categorizes TBIs by arrival Glasgow coma score (GCS). As commonly used, we defined mild brain injury as a GCS 13–15, moderate injury as a GCS 9–12, and severe as GCS 3–8. Our hypothesis was that awake patients with a SAH would have better outcomes than awake patients with other types of traumatic brain bleeds.

STUDY DESIGN AND METHODS

This is a 5-year retrospective review of data from our Level I trauma center's registry from January 2013 to December 2017. All adult trauma patients, defined as older than 15 years, and with an initial noncontrast computed tomography of the brain on admission showing the brain injury, comprised our inclusion criteria. The definition of awake was an initial GCS of 13–15. Patients included in the study were divided into two cohorts according to the type of ICH: patients with traumatic SAH without other structural brain injuries and patients with non-SAH-ICHs (subdural, epidural, and intraventricular hematomas and brain contusions, but no SAH). Demographic characteristics including age, gender, race, mechanism of injury, and injury severity score (ISS) were collected and compared between the two groups [Table 1]. To determine if predicted survival was similar, probability of survival (Ps) was determined using the revised trauma score and ISS (TRISS Methodology). TRISS was calculated from the ISS, patient's age, and vital signs including systolic blood pressure, respiratory rate, and GCS. A higher TRISS equates to a lesser injury and higher Ps.[8] Indications for intracranial pressure (ICP) and cerebral perfusion pressure monitoring were structural injury and inability to monitor neurological examination and unilateral or bilateral posturing. Neurosurgical decompression (decompressive craniectomy, craniotomy, or burr holes) was utilized for ICP >20 mmHg, despite medical efforts. Additional indications for neurosurgical intervention were bleed causing midline shift of ≥5 mm and/or compression of the basal cisterns, bleed with width >10 mm in thickness, or bleed associated with a GCS decreased by ≥2 points from the time of hospital admission. For an epidural hemorrhage, the indications for surgery were size >30 mL in volume regardless of GCS. The remainder of our facility protocol followed the Trauma Quality Improvement Programs, TBI treatment goals. Chi-square and t-test analyses were used with statistical significance defined as P < 0.05.

Table 1.

Demographics characteristics of patients with subarachnoid hemorrhage versus nonsubarachnoid hemorrhage-intracranial hemorrhage

	SAH	Non-SAH	P
Number of patients	225	826
Average age (years)	64.2	61.3	NS
Percentage male	52.4	51.8	NS
Percentage blunt injury	99.6	98.7	NS
ISS	8.51	17.6	<0.05
Comorbidities (%)
0	16.6	16.7	NS
1	22.0	33.3	NS
2	26.5	16.7	NS
≥3+	34.5	33.3	NS
Percentage TRISS	0.973	0.957	NS
Average AIS head	2.19	4.12	<0.05
Average AIS thorax	1.00	1.15	NS
Average AIS abdomen	0.59	0.35	NS
Average AIS spine	0.65	0.28	NS
Average AIS UE	0.59	0.63	NS
Average AIS LE	0.78	0.62	NS

AIS: Abbreviated injury score, TRISS: Trauma and injury severity score, ISS: Injury severity score, NS: Not significant, SAH: Subarachnoid hemorrhage, UE: Upper extremity, LE: Lower extremity

RESULTS

A total of 12,482 trauma patients were admitted during the 5-year study period ending on December 31, 2017, of which 261 had a SAH and 1075 had a non-SAH-ICH. To these groups, we applied the awake criteria and this reduced the population to 225 awake patients with a SAH and 826 awake patients with a non-SAH-ICH. The demographics of the two groups are listed in Table 1. The ages were similar for the awake SAH and awake non-SAH-ICH patients (64.2 vs. 60.8, P > 0.05). The comorbid conditions were also similar [Table 1]. The ISSs were, however, different. The mean ISS for SAH and non-SAH-ICHs was 8.51 versus 17.6, P < 0.05. This is not surprising; the ISS is calculated from the abbreviated injury score (AIS) 2005 edition. Both SAH and non-SAH-ICH were evaluated based on GCS. Since we defined the patient population as awake and with a GCS of 13–15, the AIS score was set to 2 for SAHs [Table 1], by definition, while the other types of ICHs use size as a grading scale. AIS head was significantly higher in non-SAH-ICH versus SAH (4.12 vs. 2.19, P < 0.05). There was no significant difference in AIS thorax, abdomen, spine, and extremities between groups [Table 1]. SAH and non-SAH-ICH also had a similar Ps (97.3% vs. 95.7%, P > 0.05). There was, however, a significant difference in the mortality rate. The actual death rate in SAH was significantly lower than non-SAH-ICH (4/225 [1.78%] vs. 22/826 [2.66%], P < 0.05). There was also a difference in the need for neurosurgical intervention. The SAH group required significantly less neurosurgical interventions than the non-SAH-ICH group (2/225 [0.89%] vs. 100/826 [12.1%], P < 0.05) [Table 2].

Table 2.

Outcome measures for a subarachnoid hemorrhage versus nonsubarachnoid hemorrhage-intracranial hemorrhage

	SAH	Non-SAH-ICH	P
Mortality (%)	4/225 (1.78)	22/826 (2.66)	<0.05
Neurosurgical intervention (%)	2/225 (0.89)	100/826 (12.1)	<0.04
Increased ICP (%)	0/225 (0)	8/826 (0.97)	<0.05
Average vent days	0.973	1.72	<0.044
Average ICU days	3.75	5.82	<0.002
Average hospital days	7.14	7.81	NS

NS: Not significant, SAH: Subarachnoid hemorrhage, ICH: Intracranial hemorrhage, ICP: Intracranial pressure, ICU: Intensive care unit

DISCUSSION

In our study, despite a similar predicted death rate, patients with SAH and presenting GCS 13–15 were less likely to die than patients with a non-SAH-ICH with an initial GCS of 3–15. The results of this study and others like it can also be used to establish protocols guiding the surgical care of traumatic ICH patients at trauma centers. This study also supports that trauma axiom that SAHs are a lesser injury, despite similar predicted morality. SAH also had significantly less need of surgical intervention when compared to other TBI bleeds. In the literature, there are two other studies that demonstrated similar findings.[9,10] Overton et al. suggest that a selective neurosurgical consultation policy for patients with mild traumatic ICHs could reduce the amount of neurosurgical consultations without impact on patient outcomes, implying that patients could be effectively managed on a trauma service without mandatory neurosurgical consultation.[7] Our study would support this concept. According to the Centers for Disease Control and Prevention data, TBI is linked to over 80 billion dollars a year in health-care costs in America.[4] Combining our study with other studies could help shape a triage process to reduce hospital and patient costs. The intervention rate in awake SAHs is low, perhaps short or no intensive care unit (ICU) resources are needed. This study provides an opportunity to encourage proper allocation of ICU resources which could potentially lower patient and hospital cost and safely limit ICU admission or reduce ICU length of stay for awake patients with SAH without compromising the quality of care provided.

There are limitations to our study; i.e. this was a single institution results. We also did not control for the other specific radiological features of each ICH, such as the location of the lesion, side of lesion, or volume of bleed. Despite a similar predicted mortality rate, the ISS was different between the two groups. We only followed the outcomes to hospital discharge.

Future studies should explore more specific and long-term outcome measures such as hospital disposition and patient's functional status on discharge to describe neurological improvement after traumatic ICH compared to baseline before the injury.

CONCLUSION

An awake patient with a traumatic SAH is associated with significantly lower mortality than awake patients with other types of TBI. Awake patients with a SAH are also associated with significantly less need for neurosurgical intervention than other types of traumatic brain bleeds.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.