Pediatric Trauma Scoring System in Predicting Mortality

PEDIATRIC TRAUMA SCORE AS PREDICTOR OF OUTCOME OF PATIENTS ADMITTED TO CENTRALIZED SURGICAL INTENSIVE CARE UNIT IN A GOVERNMENT TERTIARY HOSPITAL: A RETROSPECTIVE COHORT STUDY

I. Justification of the Study

Intensive trauma care of pediatric patients is faced with many issues such as quality of care, efficiency and cost-effectiveness. Scoring systems such as the Pediatric Trauma Score can aid in clinical decision making through objective measurement of severity of illness in relation to a particular outcome such as mortality or morbidity. In particular, scoring systems have become the standard for intensive care unit outcome and efficiency benchmarking. Furthermore, there is considerable difference between clinicians’ prognostication estimates. Early identification of patients with high probability of mortality can help families with difficult decisions, prevent unnecessary suffering and help direct limited resources to a more practical use. Thus, this study will investigate the use of a simple Pediatric Trauma Scoring system in predicting mortality.

II. Relationships of research objectives, data substrates, operationally-defined variables and data analyses.

TOPIC BACKGROUND

Intensive trauma care of pediatric patients is faced with many issues such as quality of care, efficiency and cost-effectiveness.¹ Quantitative observations of severity of illness in pediatric trauma using scoring systems has the potential to impact overall evaluation from baseline presentation to case endpoints.² Scoring systems have become the standard for intensive care unit outcome and efficiency benchmarking.¹ Early identification of patients with high probability of mortality can help families with difficult decisions, prevent unnecessary suffering and help direct limited resources to a more practical use.¹

A Pediatric Trauma Score (PTS) was developed with grading variables commonly seen in pediatric trauma accounting for the unique physiological and anatomical nature. The PTS consists of six variables. Each variable is scored +2 for minimal or no injury, +1 for minor or potentially major injury, or -1 for major or life-threatening injury. The total score ranges from +12 to -6 with increasing severity.³ Scoring systems such as the Pediatric Trauma Score can aid in clinical decision making through objective measurement of severity of illness in relation to a particular outcome such as mortality or morbidity.⁴ Several studies revealed consistently the direct linear relationship between Pediatric Trauma Score and injury severity thereby confirming that P.T.S. is an effective predictor of both severity of injury and potential for mortality.⁵

REVIEW OF RELATED LITERATURE

Most of the scoring systems are not appropriate for pediatric trauma patients. Variables such as respiratory rate, heart rate, and systolic blood pressure differ with infancy and childhood. In addition, the verbal response as used in GCS is not applicable for young children. For these reasons, Tepas and colleagues³ created the Pediatric Trauma Score (PTS). The authors stated that weight becomes a variable because pediatric patients had fewer physiologic reserve. Systolic blood pressure, patency of airway, level of consciousness, presence of wounds or fractures were variables included. ³ The presence of these injuries suggests severe energy transfer and positively correlates with concomitant visceral injury.¹⁰

Below is the Pediatric Trauma Score.

The assessment of severity of illness as well as mortality predictive value of the Pediatric Trauma Score (P.T.S.) was evaluated in several studies with different conclusions.

In a study by Tepas, three categories of patients with probability of mortality were identified. Pediatric trauma score of greater than 8 had a 0% mortality while pediatric trauma score between 0 and 8 had an increasing mortality related to their decreasing pediatric trauma score. Score of less than 0 had 100% mortality. This study documented the direct linear relationship between Pediatric Trauma Score and injury severity validating that P.T.S. is an effective predictor of both severity of injury and risk for mortality.⁵ Consistent with the findings of the latter, Ramenonofsky compared the evaluation of pediatric trauma patients by paramedic in the field versus the physician in the emergency room using the Pediatric Trauma Score. There was agreement between the scores of these two individuals 93.6% of the time, correlation coefficient 0.991, r2 = 0.982. The sensitivity and specificity of Pediatric Trauma Score was computed at 95.8% and 98.6%, respectively. He described Pediatric Trauma Scoring System as a straightforward modality for assessing the severity of injury.⁶ Eichelberge examined the applicability of the PTS found significant correlations with survival, Injury Severity Score (ISS) and mortality. ⁸

On the other hand, the use of PTS as a predictor of mortality was found to be inadequate in a retrospective study by Balik. Size classification was noted to be overemphasized because of the low mortality (7.7%) in children less than 10 kg. Forty-nine of 71 surgically treated patients with intra-abdominal organ injuries had a PTS >8. The existing variables of PTS did not have equal relationships to mortality.⁷

Critics have also noted that the PTS suffers from scoring ambiguity leading to misinterpretation and inadequate scoring.¹¹ Problem also arises due to a systematic bias in scoring. For example, the assessment of a patient’s consciousness can be done at the scene or on admission to the emergency department. ¹² Despite exhaustive review of the literature on Pediatric Trauma Scoring, there has been no mention of the predictive value of Pediatric Trauma Scoring done on patients upon entry to an ICU. Conclusion of studies on Pediatric Trauma Score may be less generalizable due to possible variability in settings.⁹

RESEARCH QUESTION

Among pediatric trauma patients admitted to Centralized Surgical Intensive Care Unit in Davao Regional Hospital, what is the relationship of outcome of patients to pediatric trauma score using a retrospective cohort study?

SIGNIFICANCE OF THE STUDY

Investigating the reliability of Pediatric Trauma Scoring system in predicting mortality and prolonged hospital stay is important. The results of this study can be a validation of earlier studies made on this scoring system as a tool in objective measurement of severity of illness as well as an intensive care unit outcome and efficiency benchmarking.

OBJECTIVES

1. To determine the pediatric trauma score of all patients and classify as to pediatric trauma score category of greater than 8, 0 to 8 and less than 0

2. To determine the mortality rate per pediatric trauma score category of greater than 8, 0 to 8 and less than 0

3. To determine the survival rate per pediatric trauma score category of greater than 8, 0 to 8 and less than 0

4. To determine the rate of pediatric trauma patients with prolonged hospital stay per pediatric trauma score category of greater than 8, 0 to 8 and less than 0 among surviving patients

5. To determine the risk for mortality or prolonged hospital stay among pediatric trauma patients per pediatric trauma score category of greater than 8, 0 to 8 and less than 0

METHODOLOGY

RESEARCH DESIGN

A retrospective cohort study of all pediatric trauma patients admitted to Centralized

Surgical Intensive Care Unit between January 1, 2013 to December 31, 2013 in Davao Regional Hospital will be conducted.

SETTING

This study will be conducted in Davao Regional Hospital (DRH), a tertiary hospital with 250-bed capacity, in Tagum City.

The Centralized Surgical Intensive Care Unit (CENSICU) is an intensive care unit for

adult and pediatric surgical patients in Davao Regional Hospital.

The Department of Surgery of Davao Regional Hospital is a member of the Mindanao Integrated Surgical Residency Training Program under the Department of Health, Region XI.

PARTICIPANTS

All pediatric trauma patients admitted to CENSICU in Davao Regional Hospital between January 1, 2013 to December 31, 2013 will be retrospectively included in the study.

INCLUSION CRITERIA

1. All patients admitted to Centralized Surgical Intensive Care Unit due to trauma
2. All patients aged less than 14 years old

EXCLUSION CRITERIA

1. Patients discharged against medical advice
2. Patients transferred to another hospital

OPERATIONAL DEFINITION OF TERMS

Traumaan injury to any site of the body described as multiple or single (neck, thorax, abdomen or extremeties) site caused by an extrinsic, blunt or penetrating agent

Pediatric trauma patients-patients aged less than 14 years old admitted due to trauma

Pediatric Non-Trauma patients- patients aged less than 14 years old admitted for surgical

intervention of non-trauma cause (example: intestinal obstruction due to Hirschsprungs disease, massive pleural effusion due to malignancy)

Prolonged Hospital Stay-length of hospital stay is more than 14 days with or without surgical intervention

DATA GATHERING

All pediatric trauma patients admitted to Centralized Surgical Intensive Care Unit (CENSICU) in Davao Regional Hospital between January 1, 2013 to December 31, 2013 will be identified from the admission logbook in the CENSICU of Davao Regional Hospital. The patients will be identified using the inclusion and exclusion criteria . The list of patients will be submitted to Medical Records Section of Davao Regional Hospital for chart retrieval. The charts will be reviewed for the following data will be gathered from each patient: age in years, sex, length of hospital stay in days, weight in kilograms, systolic blood pressure in mmHg, patency of airway, loss of consciousness, presence of fractures and wounds. After calculating the Pediatric Trauma Score of each patient, the category of Pediatric Trauma Score (PTS greater than 8, PTS between 0 to 8, or PTS less than 0) can be determined. In addition, the outcome of the patient will be determined as to:

1. Mortality
2. With prolonged hospital stay among surviving patients

MaIN OUTCOME MEASURES AND OTHER DEPENDENT VARIABLES

The primary outcome is the mortality rate of admitted patients categorized per pediatric trauma score of greater than 8, pediatric trauma score of 0 to 8 and pediatric score of less than 0, respectively.

The secondary outcomes are the following:

1. Number of pediatric trauma patients categorized per pediatric trauma score of greater than 8, pediatric trauma score of 0 to 8 and pediatric score of less than 0, respectively
2. Survival rate of admitted patients categorized per pediatric trauma score of greater than 8, pediatric trauma score of 0 to 8 and pediatric score of less than 0
3. Rate of surviving pediatric trauma patients with prolonged hospital stay per pediatric trauma score category of greater than 8, 0 to 8 and less than 0

INDEPENDENT VARIABLE

The identified independent variables include age, sex, weight in kilograms, length of hospital stay, patency of airway, systolic blood pressure in mmHg, level of consciousness, presence of fractures and minor or major wounds.

SAMPLE SIZE COMPUTATION

Sample size for this study was computed using Epi Info 7 StatCalc. Calculations were based on the assumptions that: 1) the ratio of patients unexposed to the risk factor (i.e., PTS greater than 8) to patients exposed to the risk factor (i.e., PTS 8 or less) is 3; and 2) the prevalence of the outcome (i.e., death) in the unexposed group is 15%. Estimations were done in order for the study to detect an odds ratio of 5 as statistically significant. In a computation for odds ratio carried out with 5% level of significance, a sample size of 79 patients will have 80% power of rejecting the null hypothesis (no significant increase or decrease in odds ratio) if the alternative holds.

DATA HANDLING AND ANALYSIS

Clinical characteristics (age in years, sex, weight in grams, length of hospital stay), systolic blood pressure in mmHg, patency of airway, loss of consciousness, presence of fractures and wounds, and Pediatric Trauma scores of patients will be compared statistically. A p value will be computed to establish whether the difference in the values were significant or not. A p value <0.05 will be considered significant.

The Pediatric Trauma Score of each patient will be calculated and the category of Pediatric Trauma Score (PTS greater than 8, PTS between 0 to 8, or PTS less than 0) to which the patient belongs will be determined. The total number of patients in each category will be evaluated.

Outcome (mortality rate or survival rate) of each patient belonging to a particular category will be tallied and each frequency computed. Among surviving patients, length of stay will be evaluated as to prolonged (>14 days) or not prolonged. Rate of surviving patients with prolonged hospital stay will be determined.

Risk of mortality as well as prolonged hospital stay among surviving patients will be expressed in odds ratios (OR) with 95% confidence interval.