FACTORS INFLUENCING MORBIDITY IN ICU TRAUMA ADMISSIONS A 3 YEAR RETROSPECTIVE ANALYSIS

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1 MULLICK, Indian J. Anaesth. TALWAR, 2004; PAWAR 48 (2) : MORBIDITY IN ICU TRAUMA ADMISSIONS 111 SUMMARY FACTORS INFLUENCING MORBIDITY IN ICU TRAUMA ADMISSIONS A 3 YEAR RETROSPECTIVE ANALYSIS Dr. Parul Mullick 1 Dr. Vandana Talwar 2 Dr. M. Pawar 3 A three year retrospective analysis of complications and the factors influencing their occurrence was carried out on all trauma patients admitted to the Intensive Care Unit (ICU) of Safdarjang Hospital, New Delhi from January 1995 to December There were a total of 107 trauma admissions to the ICU during the study period. A record of all the complications that had occurred in these patients was compiled, analysed and correlated with their age, duration of ICU stay and injury severity score. The injury severity score was also correlated with duration of stay and with percentage mortality of patients. 30% of patients aged 14 years or less had complications involving more than one body system as compared to 66.6% of patients older than 65 years of age (P<0.001). The incidence of chest infection, gastrointestinal complications and bedsores increased as the duration of stay of patients increased. No correlation was found of the injury severity score (ISS) with the incidence of complications or with duration of ICU stay of patients. Percentage mortality was found to be more in those with a higher injury severity score at the time of ICU admission. The predominant causes of morbidity were chest infection (36%), anaemia (33%), hypotension (28%), arrythmias (20%), bronchospasm (17%) and bedsores (11%). Keywords : Trauma, Intensive Care Unit, Complication. Introduction Trauma is a significant cause of morbidity and mortality throughout the world. Advances in resuscitative management has increased the survival rate of patients with multiple injuries but has rendered them vulnerable to nosocomial infections and other complications during the course of their treatment in the hospital. 1 Evaluation of trauma care is an integral part of any system designed for care of seriously injured patients. The injury severity score (ISS) is a method for numerically describing the overall severity of injury and can be applied to persons who have sustained injury to more than one area of the body as well as those with isolated injuries. 2 The ISS has been found to correlate better with mortality as compared to the abbreviated injury scale (AIS) and is generally accepted as the standard for anatomic indices of injury severity. 3 However there is a paucity of literature correlating the various demographic and clinical factors with morbidity in ICU trauma admissions. In view of this, we decided to study the various risk factors for 1. M.D., Pool Officer 2. M.D., Specialist Department of Anaesthesia and Intensive Care Safdarjang Hospital, New Delhi, India 3. M.D., Senior Specialist, Head of Department Department of Anaesthesia and Intensive Care Ram Manohar Lohia Hospital, New Delhi, India Correspond to : Dr. Vandana Talwar A I/43, Azad Apartments, Sri Aurobindo Marg, New Delhi India. vandtal@yahoo.com (Accepted for publication on ) development of complications in trauma admissions to the intensive care unit. Methods A retrospective analysis was conducted of all trauma patients admitted to the ICU of one of the largest general hospitals in New Delhi (Safdarjang Hospital which has a bed strength of 1531 beds) from January 1995 to December A record of all the complications that had occurred in these patients was compiled and correlated with their age and duration of stay in the ICU. Percentage of patients requiring ventilatory support as well as mean duration of ventilation in survivors and non survivors was calculated. All patients were assigned an ISS at the time of admission to the ICU and this was correlated with the various complications that occurred, with their duration of ICU stay and with mortality. The ISS was determined using the abbreviated injury scale (AIS) which scores each individual injury on a scale of 1(minor) to 6 (fatal). The body was divided into 6 regions: head and neck, face, chest, abdomen and pelvic contents, bony pelvis and limbs and body surface. To get the ISS, the maximum AIS score in the three worst injured areas was scored and then summed. According to their age patients were divided into four groups : Group-A less than 14 years, group-b patients between 15 to 44 years, group-c between 45 to 64 years, and group-d more than 65 years of age. And depending on the duration of stay, patients were divided into three groups : Group 1 less than 3 days of stay,

2 112 INDIAN JOURNAL OF ANAESTHESIA, APRIL 2004 group 2 between 4 days to 3 weeks, and group 3 more than 3 weeks Descriptive statistics i.e. frequency distributions of the variables considered in the study were calculated. Chi-square test was performed to see the linear trend in proportions between the ISS and the incidence of complications and to observe the statistical significance of differences in complication rates between groups 1, 2 and 3 based on duration of stay of the patients. Proportion test was applied to compare the occurrence of complications within the same group. Chi-square test with yate s correction factor was applied to correlate ISS with duration of stay of patients and to compare the incidence of ventilatory support between the groups. Chi-square goodness of fit test was used to analyse complications with respect to age. Student t test (unpaired) was applied to compare the mean duration of ventilation between survivors and non-survivors and to correlate ISS with mortality. A value of p<0.05 was considered to be statistically significant. Results There were a total of 107 trauma admissions to the ICU during the three year study period from January 1995 to December Their age and sex distribution is shown in fig.1. The complications which occurred in these patients are summarized in table % of patients required ventilatory support (table-2). No significant difference was found in the mean duration of ventilation between survivors and non survivors (table-3). The incidence of cardiovascular complications was significantly more than respiratory complications (Z=4.043; P<0.001) (table-4) in patients who stayed for less than 3 days in the ICU (group 1). However, no statistically significant difference was found between the incidence of respiratory and cardiovascular complications in groups 2 and 3 (table-4). On comparing intergroup differences we noted that the incidence of respiratory complications was significantly less (P<0.05) in group 1 as compared to groups 2 and 3 (table-4 and fig. 2). An increased incidence of gastrointestinal disturbances in group 3 as compared to group 1 (P <0.05) and an increased incidence of miscellaneous complications like bedsores in groups 2 and 3 as compared to group 1 were noted (P<0.05) (fig. 2). No statistically significant differences were found in the incidence of cardiovascular, renal and metabolic complications between the three groups (fig. 2). Table 1 : Percentage of complications seen in trauma admissions to the ICU 107 patients. Complications Patients (n=107) % Respiratory Chest infections Bronchospasm Lung collapse Pulmonary edema Pneumothorax Hydrothorax Tracheal Stenosis Cardiovascular Anaemia Hypotension Arrythmias Cardiac arrest Hypertension Renal Renal failure UTI Gastrointestinal Diarrhoea Metabolic and Electrolyte imbalance electrolytes Hyperglycaemia Miscellaneous Bed sores Exposure keratitis Local wound infection Convulsions Jaundice Depression Septicaemia Percentage of patients Fig. 1 : Age and Sex distribution Group A Group B Group C Group D <14 yrs yrs yrs >65 yrs Males : 88.78% Females: 11.22%

3 MULLICK, TALWAR, PAWAR : MORBIDITY IN ICU TRAUMA ADMISSIONS 113 Table - 2 : Percentage of patients who required ventilatory support during ICU stay. Group (n) No. of patients Ventilatory support required Percentage 1 (42) (54) (11) P=0.08 Table - 4 : Percentage of complications according to duration of stay. Duration Respir- Cardio- Renal Gastroin- Metabolic Miscellaof Stay atory vascular testinal and neous electrolytes Group I 16.66% 64.82% 2.38% % 2.38% (n=42) (7) (27) (1) (4) (1) Group II 61.11% 57.4% 11.11% 7.4% 9.25% 37.03% (n=54) (33) (31) (6) (4) (5) (20) Group III 81.81% 63.63% 9.09% 27.27% 9.09% 72.72% (n=11) (9) (7) (1) (3) (1) (8) Grp I CVS vs Resp. P <0.05 Gastro Grp I vs Grp 3 P <0.05 Resp. Grp I vs Grp 2 P<0.05 Misc. Grp I vs Grp 2 P <0.05 Grp I vs Grp 3 P <0.05 Grp I vs Grp 3 P <0.05 Fig - 4 : Correlation of ISS with mortality Injury severity score Table - 3 : Mean duration of ventilation No. of patients Duration of Mean ± S.D. ventilation (days) Survivors ±11.22 Non-survivors ±9.34 t-value =0.78 As the age of the patients increased, the number of patients with complications involving more than one body system increased from 30% in group A to 66.6% in group D. Survival rate of 50% seen in age group less than 44 years (i.e. groups A and B) declined to 20% and 16.6% in groups C and D respectively (P<0.001) (fig.-3). No correlation was found between the ISS and incidence of complications (table-5) and between ISS and duration of ICU stay of patients (table-6). However the relation between mortality and a rising ISS was found to be highly significant (p=0.0016) (fig. 4). Total ICU mortality in trauma patients was found to be 57%. Table 5 : Correlation of ISS with incidence of complications ISS No. of Resp. CVS Renal GIT Metabolic Misc. Total patients and (n=107) electrolyte < ³

4 114 INDIAN JOURNAL OF ANAESTHESIA, APRIL 2004 Table - 6 : Correlation of ISS and duration of stay P=0.23 ISS Group 1 Group 2 Group 3 < > Discussion Advances in resuscitative management of trauma has resulted in an increased survival rate in patients. The use of invasive diagnostic and therapeutic procedures has however increased their susceptibility to infection through creation of multiple portals of entry for bacteria. 1 In addition, trauma leads to a state of relative immunosuppression with decreased humoral and cell mediated immunity. 4,5,6 Prolonged ICU stay further exposes the seriously injured to a multitude of problems like anaemia, inadequate nutrition and multiple transfusions. We correlated the complications that had occurred in trauma admissions with their duration of stay in the ICU. No difference was found in the incidence of cardiovascular complications between patients with different durations of stay. Two-third of patients who stayed for less than 3 days developed cardiovascular complications, the commonest among them being hypotension and anaemia secondary to acute haemorrhage. 50% of patients in this group had presented with haemoperitoneum secondary to blunt trauma abdomen, 10% with stab injury to the neck and 5% with gun shot injury. All these patients had bled excessively either preoperatively, intraoperatively or in both these periods and were brought to the ICU for post operative management. Shock and hypotension in the trauma patient are caused by hypovolemia secondary to haemorrhage until proven otherwise. In traumatic shock, the oxygen transport function is compromised at multiple levels causing hypoxemia, hypoventilation, acidemia, hypothermia and peripheral hypoperfusion. 7 Trauma patients may therefore be haemodynamically unstable at the time of ICU admission and management of the cardiovascular parameters should be a priority at this stage. In patients who stay for a longer time in the ICU, anaemia may occur secondary to inadequate nutrition, repeated sampling, bone marrow depression or occult blood loss. 8 Chest trauma which occurred in 12% of patients in group 1 may have contributed to the 16% incidence of respiratory complications seen in this group. Although 85% of patients were on ventilatory support, only 2.38% developed chest infection, probably due to their short duration of stay. Stillwell and Caplan observed that it is uncommon for infection to arise in hospitalized trauma patients within the first 2 or 3 days after injury. 4 In contrast, we found a predominance of respiratory complications in both groups 2 and 3. In group 2, bronchospasm occurred in 25.92% and lung collapse in 5.5% of cases. One patient (1.8%) in this group developed hydrothorax secondary to a malpositioned central venous pressure (CVP) line. Two patients in group 3 (18%) developed tracheal stenosis as a result of prolonged intubation and tracheostomy. Chest infection occurred in 55.55% of patients in group 2 and % of patients in group 3. The significantly higher incidence (P<.001) of chest infection seen in both these groups may be attributed not only to the higher incidence of chest trauma, but also to the longer duration of mechanical ventilation as compared to group 1. Langer and colleagues noted that the incidence of nosocomial pneumonias increased with the duration of mechanical ventilation, being less than 5% in patients treated for less than a day on a ventilator and close to 70% if mechanical ventilation extended for over 30 days. 9 Gastrointestinal complications were not seen in patients who stayed for less than 3 days in the ICU. However, in patients with a longer duration of stay, a significantly increased incidence of diarrhoea was noted. Enteral nutrition, impaired digestion and absorption following trauma, drug therapy, gut atrophy or gut infection are some of the commoner causes of diarrhoea seen in the ICU. 10 Incidence of miscellaneous problems was higher in patients of group 3 (72%) as compared to groups 1 (2.38%) and 2 (37%). Prolonged immobilization increased the incidence of bed sores which occurred in 54.54% of patients in group 3 as compared to only about 11% in group 2 and none in group 1. On correlating complications in trauma admissions with age, we found that involvement of more than one body system was 30% in patients less than 14 years of age as compared to 66% in those older than 65 years. We also noted a significant decrease in survival as the age of the patients increased. Antonelli et al in 1999, analyzed 181 trauma patients in the ICU and found that the 34 nonsurvivors were significantly older than the 147 survivors. They showed that the death rate of patients aged over 65 years was 4.9 times that of those under 65 years of age (p<0.001). 11 Diminished physiologic reserve and deficiencies in management contribute to higher rates of morbidity and mortality in the elderly patient with trauma as compared to the younger patient with equivalent trauma as quoted by Lonner and Koval. 12 The outcome from critical illness in the elderly population has been observed to be poor by

5 MULLICK, TALWAR, PAWAR : MORBIDITY IN ICU TRAUMA ADMISSIONS 115 Ridley et al, who noted long term survival to be related to both the severity of illness and age of the patients in the ICU. 13 Copes et al in their study on 23,000 patients found that in patients more than 55 yrs of age there was a significantly increased mortality as compared to younger patients for comparable levels of physiological derangement and anatomic injury severity. 14 Patients were admitted to our ICU with varying severity of trauma. To objectively analyze the extent of trauma, we assigned an ISS to all the patients and correlated this with their duration of ICU stay and with the various complications that had occurred. However, we did not find an increased duration of stay or an increase in complication rate in patients with a higher ISS. This maybe attributed to the fact that patients with a higher ISS died before developing complications. This is further substantiated by our study in which we have shown that percentage mortality was more in patients with a higher ISS. In contrast, Semmlow and Cone found the days of hospitalization and the percentage of patients with major surgical procedures to increase linearly with ISS. 3 Moylan and others who used the ISS in an evaluation of the quality of care of hospital patients with major trauma, recommend that patients with severity scores above 30 should receive special attention from panels reviewing trauma care. 15 We found the percentage mortality to be more in patients with a higher ISS, being 16.6% at an ISS of less than 10, in contrast to 100% at an ISS of more than 41. An ISS of 16 is predictive of 10% mortality and defines major trauma based on anatomic injury. 16 The closest agreement between ISS and survival has been found for scores of 40 or less. 3 The Baltimore and Birmingham studies clearly demonstrated the rise in percent mortality with an increasing ISS, being almost 20% at an ISS of To summarize, the predominant complications seen in trauma admissions to the ICU were chest infection (36%), anaemia (33%), hypotension (28%), arrythmias (20%), bronchospasm (17%) and bedsores (11%). The main factors influencing morbidity were duration of stay and age of the patients. Anaemia and hypotension were the predominant complications seen in patients who stayed for less than 3 days in the ICU. The incidence of chest infections, gastrointestinal complications and bedsores increased as the duration of stay of the patients increased. Complication rate also showed an increase with age and survival of only 16% was noted in the elderly more than 65 years of age as compared to 50% in those younger than 44 yrs. Occurrence of complications and duration of stay did not show any correlation with the ISS. Mortality was however more in patients wth a higher ISS, being 100% at an ISS of more than 41. Management of cardiovascular parameters is of prime importance in the initial 3 days of ICU stay, since trauma patients are haemodynamically unstable at that time. Subsequently we should aim at decreasing the incidence of chest infection, anaemia and bedsores in patients who stay for a longer period of time. This will not only shorten their ICU stay but also decrease the subsequent morbidity and mortality of patients. References 1. Giuseppe P, Barry AM, Philippe EH et al. Infection in hospitalized trauma patients: Incidence, risk factors, and complications. J Trauma 1999; 47(5): Baker SP, O Neill B. The Injury Severity Score: An Update. J Trauma 1976; 16 (11): Semmlow JL, Cone R. Application of the Injury Severity Score; An Independent correlation. Health Serv Res 1976; 11: Stillwell M, Caplan ES. The septic multiple-trauma patient. Infect Dis Clin North Am 1989; 3: Morgan AS. Risk factors for infection in the trauma patient. J Natl Med Assoc 1992; 84: O Mahony JB, Palder SB, Wood JJ, et al. Depression of cellular immunity after multiple trauma in the absence of sepsis. J Trauma 1984; 24: Marc DP, Vicente Cortes. Secondary Triage of the trauma patient. In Joseph M Civetta, Robert W Taylor, Robert R Kirby editors. Critical Care third edition. 1997; Chapter 68: Seeley HF. Artificial ventilation. In : HC Churchill Davidson editors. Wylie and Churchill Davidson s A practice of Anaesthesia. 5 th ed., 1984; Langer M, Mosconi P, Cigada M et al. Long term respiratory support and risk of pneumonia in critically ill patients. Am Rev Respir Dis 1989; 140: Pamela RR, Gary PZ. Enteral nutrition. In: Ake Grenvik, Stephen M Ayres, Peter R. Holbrook and William C. Shoemaker editors. Textbook of Critical Care 4 th ed., 2000; Chapter 79: Antonelli M, Moreno R, Vincent JL et al. Application of SOFA score to trauma patients. Intens Care Med 1999; 25: Lonner JH, Koval KJ. Polytrauma in the elderly. Clin-orthop. 1995; 31: Ridley S, Jackson R, Findlay J et al. Long term survival after intensive care. BMJ 1990; 301(6761): Copes, WS : Personal communication in re major trauma outcome study to participating trauma centers Moylan JA, Detmer DE, Rose J et al. Evaluation of the quality of hospital care for major trauma. J Trauma 1976; 16: Boyd CR, Tolson MA, Copes WS. Evaluating Trauma Care: The TRISS Method. J Trauma 1987; 27(4):