Overview:
Between January 2003 and December 2012 there were 1122 patients were admitted to our institution due to trauma. Out of them 1070 patients (95%) had blunt trauma. 630 patients (56%) had thoracic trauma (TT). Group I (between Jan. 2003-Dec. 2007) consisted of 285, group II (between Jan. 2003-Dec. 2007) consisted of 345 patients. Patient’s characteristics are summarized (table 1). Out of them, there were 90 patients (14%) with isolated TT, but 540 patients (48%) had associated extra thoracic injuries. 392 (34%) had two systems affected. 311 patients (27%) had three or more organs affected. The associated injures included: 505 (80%) head and maxillo facial trauma, 271 (43%) extremity injuries, 127 (20%) abdominal injuries, 184 (29%) pelvic fractures, 67 patients (10%) had urological trauma, 45 (7%) spine injuries, 30 (3%) with considerable soft tissue injury (table 2). Most of the patients in both groups had blunt thoracic trauma (88% vs. 92%). 55% (n=352) had loss of conscious at the accident place with Glasgow coma scale (GCS) ≤ 8 (57% in group I vs. 54% in group II). Most of the patients arrived intubated in both groups (84% in group I vs. 85% in group II). 8% had signs of aspiration in group I vs. 7% in group II. Gastric tube was inserted in 41% in group I vs. 46%. There were 68% (n=196) arrived with chest tube in group I vs. 60% (n=208). A new chest tube was inserted, or the old one was corrected or a second chest tube was inserted in 10 % (n=29) in group I vs. 23% (n=80) in group II. Young patients under 40 years were frequently exposed to severe thoracic injury with higher ISS and AIS thoracic but showed less mortality rates (p=0.014). Overall morbidity was 52%, n=331 (58% in group I vs. 43% in group II). In both groups; higher mortality rates was noticed in patients with higher AISthoracic especially due to respiratory complications (p<0.0001). In this sub group of patients with higher AISthoracic, higher incidence of acute pulmonary failure which needed long time respiratory support with or without extra corporeal membrane oxygenation (ECMO) as well as extra corporeal CO2 elimination using interventional lung assist (iLA) Novalung® (p=0.031) was noticed. Univariate and multivariate analysis showed higher mortality rates in patients with severe lung contusions (p<0.001). In this sub group higher occurrence of pneumonia and ARDS was noticed especially in patients with more than 50% involvement of both lungs. Intubation time was 15 days vs. 11 in group II. 8% (n=23) Patients had emergency thoracotomy vs 4% (n=13) patients in group II (p=0.042). Much more VATS procedures as well as surgical chest wall fixation were done in group II (p=0.014) (table 2). Mean ICU stay was 29 days (range 3-58) in group I vs. 34 days (range 2-67) in group II, mean hospital stay was 34 days (range 5-86) vs. 31 days (range 6-94)in group II with no statistical difference. As well as no statistical difference was noticed between patients in both groups in form of sex, type of transport, type accident, blood transfusion, or accompanied injuries of other organs. Overall 90 days mortality rate was 16% (n=48) in group I vs. 9% (n=31) in group II (p=0.024).
Injury Severity Score (ISS):
The ISS is an anatomical scoring system that provides an overall score for patients with multiple injuries. Each injury is assigned an Abbreviated Injury Scale (AIS) and is allocated to one of six body regions (head, face, chest, abdomen, extremities (including pelvis). Only the highest AIS score in each body region is used. The 3 most severely injured body regions have their score squared and added together to produce the ISS score. The ISS score takes values from 0 to 75. If an injury is assigned an AIS of 6 (un survivable injury), the ISS score is automatically assigned to 75. The ISS score is virtually, and it is the only anatomical scoring system in use and correlates linearly with mortality, morbidity, hospital stay and other measures of severity. Its weaknesses are that any error in AIS scoring increases the ISS error, many different injury patterns can yield the same ISS score and injuries to different body regions are not weighted. Also, as a full description of patient injuries has not known prior over full investigation & operation, the ISS (along with other anatomical scoring systems) is not useful as a triage tool. 555 Patient (88%) with severe thoracic trauma had ISS ≥ 16. ISS is summarized and compared in both groups (table 4). Mean ISS score was 32 (28 in Group I vs. 33 in group II). Univariate and multivariate analysis showed higher morbidity with higher risk of respiratory and cerebral complications in patients ISS > 30 (p=0.026). Higher mortality rate in patients with ISS > 30 (p<0.0001) was also identified.
Abbreviated Injury Scale (AISThoracic):
The AISthoracic is an anatomical-based coding system created by the Association for the Advancement of Automotive Medicine to classify and describe the severity of specific individual injuries. There were 124 patients (43%) with AIS thoracic 4 and 5 in group I comparing to 154 (45%) in group II. Summary of the patient’s AISthoracic Score in both groups was analysed and compared (table 5). Higher mortality rate in patients with AIS thoracic > 3 (p<0.0001) was identified in both groups.
Mechanism of injury:
The most frequent mechanism of injury in the overall study population was Road Traffic Accidents (RTAs) 57%. Car crashes being the most frequent cause among RTAs (36.4%) followed by motorcycle crashes (16.8%) and injured pedestrians (7.4%). Falls made up for most of the remaining injuries (23.9%). Injuries caused by bicycle were represented by 7.3%. There were 6% (n=37) in whom no defined mechanism could be obtained.
Type of associated non thoracic injures:
Associated extra thoracic injuries were most frequently in the head and neck region, lower then upper extremities, followed by abdominal injuries, followed by pelvic injuries. An overview is summarized an compared in both groups (table 2).
Type of thoracic injuries:
The most common thoracic injuries were lung contusion followed by hemothorax, rib fractures, and then pneumothorax. The prevalence of common thoracic injuries was analysed and compared in both groups (in table 6).
Degree of lung contusion:
322 patients (51%) had mild lung contusions, 138 patients (22%) had moderate, and 94 patients (15%) had severe lung contusion. The presence of pneumoceles and other signs of lung lacerations were frequently seen in both moderate and severe lung contusion, but on itself, did show significant difference neither on complication nor on mortality rates.
The degree of lung contusions was classified according to the findings on CT-scan of the lung. The volume of lung contusion was calculated according to the relation of the affected volume to the non affected lung volume (Fig. 1). Following classification was done:
Mild lung contusion: less than 20% of the whole lung volume affected. There were 146 patients in Group I (two patients died, 1,3%) and 176 patients in group II (one died, 0,56%)
Moderate lung contusion: 20-50% of the whole lung volume affected. There were 65 patients in Group I (four died, 6%) and 73 patients in group II (five died, 6,8%)
Severe lung contusion: more than 50% of the whole lung volume affected. There were 33 patients in Group I (18 died, 54%) and 61 patients in group II (13 died, 21%); (p<0.001).
Morbidity/mortality:
Complications were documented, analysed and compared in in both groups. 22 patients (7%) had nosocomial pneumonia in group I vs. 10 patients (2,8%) in group II (p = 0.033). More patients with atelectasis in group I (n=34) than in group II (n=12) were observed (p = 0.019). ARDS was more noticed in group I (n=16) vs group II (n=5) (p = 0.016). Organ replacing procedures e.g. ECMO, Novalung, Jet ventilation as well as renal dialysis were frequently used in group II (n=109) than in group I (n=51) (p = 0.038). The overall 90 days mortality was 13% (n=79). Higher mortality in group I (n=48) than group II (n=31) with lower incidence in younger patients under 40 years old (p = 0.024) and p = 0.014) respectively was noticed. Other complications like: Re operation, pleural empyema, cardio vascular, lung emboli and neurological complications were higher in group I but did not show statistical differences.