Outcome of severe traumatic brain injury at a critical care unit: a review of 87 patients

Author Information

E.A. Opondo, MBChB, MMed (Surg), General surgeon, North Kinangop Mission Hospital, Surgery Department and The Mater Hospital Nairobi, surgery department, N.J.M. Mwangombe, MBChb, MMed(surg), PhD (Lond), Associate Professor, Department of Surgery, University of Nairobi and Head Division of Neurosurgery

Corresponding author:

Dr. E.A. Opondo, P.O. Box 00202105, Nairobi, Email dropondo@yahoo.co.uk

Abstract

OBJECTIVE: To determine the outcome of severe traumatic brain injury and to document the factors influencing mortality.

DESIGN: A six months prospective study.

SETTINGS: The intensive care unit (ICU) of Kenyatta National Hospital (KNH), a tertiary referral centre in Kenya.

SUBJECTS: Eighty Seven adult patients with severe traumatic brain injury admitted between April and September 2005.

METHODS: Basic demographic, clinical, radiological and mechanism of injury data were recorded at admission and during ICU stay. The main outcome measure was survival or death. The outcome groups were compared for the injury severity, mean arterial pressure, serum glucose level, grade of diffuse axonal injury and the presence of mydriasis and anisocoria using the X2 test and the Fischers Exact test as appropriate.

RESULTS: Severe traumatic brain injury accounted for 14.3% of all ICU admissions. This study included 73 men (83.9%) and 14 women (16.1%) with a mean patient age of 34 ± 17 years. Motor vehicle accidents were the main cause (58.6%). Forty six patients (54.0%) died. Twenty nine percent of patients had persistent vegetative state or severe disability. Factors that were associated with poor outcome on univariate analysis were Glasgow coma scale of less than 5, diffuse axonal injury and intracerebral mass lesions and blood sugar greater than 10mmol / L.

CONCLUSION: Severe TBI is a frequent cause of hospital admission to critical care units among young men with a high mortality (54%) rate.

 

Introduction

Traumatic brain injury (TBI) has been termed a “silent global epidemic”, accounting forup to 30% of all trauma related deaths and is the leading cause of death in young males in developed countries (1, 2). It is considered to be a dual insult comprising primary and secondary processes. The primary injury is the physical or anatomic damage caused at the time of injury producing vulnerable cells that are further compromised by secondary brain injury factors (3-6). The factors commonly associated with secondary insults include hypotension, hypothermia, hypoxia, acidosis and raised intracranial pressure (1,3,5). When these are present, mortality rises to 35-36% (1,5) as documented in the Traumatic coma Data Bank study (1884-1987) and that by Jeremitsky et al. In an earlier study at the Kenyatta National Hospital (KNH), patients with a pulse rate of less than 60 per minute at the time of admission had a mortality of 100% while 69% of those with pulse rate greater than 120 per minute had poor outcome (7). In managing severe TBI therefore, avoiding secondary brain injury is key.

The accurate prediction of short term and long term outcomes is useful for communication with the patient’s family and health care professionals. Of the commonly used outcome measures, the Glasgow outcome scale is the oldest. It consists of five categories namely death, persistent negative state, severe disability, moderate disability and good recovery. The current study aimed to evaluate the outcome and predictors of outcome of severe traumatic brain injury at ICU of Kenyatta National Hospital.

Materials and methods

Patients: This prospective study included all the consecutive adult patients with severe traumatic brain injury admitted to the ICU of Kenyatta National Hospital between April and September 2005.They were examined by the first author and scored according to Glasgow coma scale (GCS) on arrival. They then underwent computed tomography (CT scan) as soon as this was practical. The study excluded patients with GCS of greater than 8 as those were admitted to the general wards. Patients meeting the study criteria were resuscitated according to advanced trauma life support (ATLS) protocols with supervision of the attending surgeon. Further data was collected on the cause of TBI, age, gender, vital signs and pupillary responses. Anisocoria was defined as pupillary inequality of more than 1 mm and mydriasis as fixed and dilated pupils of 4mm or more in diameter. Hypotension was defined as mean arterial pressure of less than 70mmHg. The biochemical parameters measured at admission and during ICU stay included arterial blood gases, acid-base state, serum glucose and electrolytes.

Outcome data included hospital complications, mortality, status at discharge from ICU and length of ICU/hospital stay recorded. The CT scans were reported by one radiologist in collaboration with the investigators and classified according to Marshal’s classification. In this classification, the status of the mesencephalic cisterns, the degree of midline shift in millimeters, and the presence or absence of one or more surgical masses are considered. Diffuse Injury I included all head injuries where there was no visible pathology;Diffuse Injury II included all injuries in which the cisterns were present, the midline shift was less than 5 mm, and/or there was no high- or mixed- density lesion of more than 25 cc; Diffuse Injury IIIincluded injuries with swelling where the cisterns were compressed or absent and the midline shift was 0 to 5 mm with no high- or mixed-density lesion of more than 25 cc; and Diffuse Injury IVincluded injuries with a midline shift of more than 5 mm and with no high- or mixed-density lesion of more than 25 cc The outcome status was based on the Glasgow Outcome Score which ranged from good recovery to death in five categories.Good recovery was defined as capacity to resume normal occupational activities, while withmoderate disability the patient was independent and resumed only part of activities of daily living. In case of severe disability the patient was not able to engage in most previous personal, social and work activities unless with some form of assistance, while in persistent vegetative state the patient was not aware of surroundings or only partially responded to stimuli. Poor outcome in this study was defined as death, persistent vegetative state or severe disability.

Statistical analysis: Analysis of the data was carried out using SPSS version 12 program to derive descriptive statistics and frequency distributions. Categorical data were expressed in terms of proportions while continuous variables were expressed as means and standard deviations.

Subgroups (survival & death) were analyzed in a univariate way using student t-test, chi square test and Ficher exact tests as appropriate. Significance was set at p less than 0.05.

Results

Patient and injury characteristics: Eighty seven patients were reviewed. This represented 14.3% of the 609 adult ICU admissions. There were 73 men (83.9%) and 14 women (16.1%) with a mean age of 34 ± 17 years. The demographic and clinical parameters at admission are shown in Table 1.

Majority of the patients were aged 25-39 years (50.6%), while 21% were 40-60 years. Five percent of the patients were aged over 60 years.

Trauma in majority of the patients was due to motor vehicle accidents (58.6%) followed by assaults in 32.2%. Three patients (3.4%) were received in coma having been found on the streets by policemen with no clear history about their injuries being availed (Table 2).

Extracranial pathology was present in 78 patients (91.6%). Maxillofacial injury was present in 53 patients (49.5%) and limb fractures were seen in 27 patients (25.2%). Twenty of the patients with limb fractures had operative fixation and the rest were managed conservatively. Ten patients had a combination of limb fractures and maxillofacial injury while five patients had maxillofacial injury, chest trauma, and limb injury combined. Four patients presented with abdominal injuries (2 with splenic ruptures).

Fifty two patients (59.8%) were seen at the casualty within 1-4 hours of injury while 4.5% presented between 4 and 24 hours after injury. The rest arrived within an hour. On admission 43 patients (49.4%) had GCS of 3-5 and 44 patients (50.6%) had GCS of 5-8.

Fifteen patients with intracranial haematomas or mass lesions underwent craniotomy, burr holes and elevation of skull fractures based on the assessment of a neurosurgeon.

Outcome evaluation: Forty five patients died on the initial ICU admission while one with severe disability died on readmission to ICU from the wards (total mortality of 54%). On discharge from ICU, 19 (21.8%) patients had persistent vegetative state, 7(8.0%) severe disability, 7(8.0%) moderate disability and 9(10.3%) had good recovery.

A number of patients and clinical parameters were related to outcome. Poor outcome in the age group 25-39 was 52.3%, 40-60 years (23.1%), 15-24 years (16.9%) and for those over 60 years (7.7%). Both the patients wit