Greg E. Gaski

Tissue damage volume predicts organ dysfunction and inflammation after injury

BACKGROUND Multiply injured patients (MIPs) are at risk to develop multiple-organ failure (MOF) and prolonged systemic inflammation response syndrome (SIRS). It is difficult to predict which MIPs are at the highest risk to develop these complications. We have developed a novel method that quantifies the distribution and physical magnitude of all injuries identified on admission computed tomography scanning called the Tissue Damage Volume (TDV) score. We explored how individualized TDV scores corresponded to MOF and SIRS. MATERIALS AND METHODS A retrospective study on 74 MIPs measured mechanical TDV by calculating injury volumes on admission computed tomography scans of all injuries in the head/neck, chest, abdomen, and pelvis. Regional and total TDV scores were compared between patients that did or did not develop MOF or sustained SIRS. The magnitude of organ dysfunction was also stratified by the magnitude of TDV. RESULTS Mean total and pelvic TDV scores were significantly increased in patients who developed MOF. Mean total, chest, and abdominal TDV scores were increased in patients who developed sustained SIRS. The magnitude of organ dysfunction was significantly higher in patients who sustained large volume injuries in the pelvis or abdomen, and in patients who sustained injuries in at least three anatomic regions. CONCLUSIONS A novel index that quantifies the magnitude and distribution of mechanical tissue damage volume is a patient-specific index that can be used to identify patients who have sustained injury patterns that predict progression to MOF and SIRS. The preliminary methods will need refinement and prospective validation.

SHOCK VOLUME: A PATIENT-SPECIFIC INDEX THAT PREDICTS TRANSFUSION REQUIREMENTS AND ORGAN DYSFUNCTION IN MULTIPLY INJURED PATIENTS.

ABSTRACT Multiply injured patients (MIPs) in hemorrhagic shock develop oxygen debt which causes organ dysfunction and can lead to death. We developed a noninvasive patient-specific index, Shock Volume (SV), to quantify the magnitude of hypoperfusion. SV integrates the magnitude and duration that incremental shock index values are elevated above known thresholds of hypoperfusion using serial individual vital sign data. SV can be monitored in real time to assess ongoing hypoperfusion. The goal of this study was to determine how SV corresponded to transfusion requirements and organ dysfunction in a retrospective cohort of 74 MIPs. We measured SV in 6-h increments for 48 h after injury in multiply injured adults (18–65; Injury Severity Score ≥18). Patients who had accumulated 40 units of SV within 6 h of injury and 100 units of SV within 12 h of injury were at high risk for requiring massive transfusion or multiple critical administration transfusions. SV measurements were equally sensitive and specific as compared with base deficit values in predicting transfusions. SV measurements at 6 h after injury stratified patients at risk for multiple organ failure determined by Denver scores. In addition, SV values corresponded to the magnitude of organ failure determined by Sequential Organ Failure Assessment scores. SV is a patient-specific index that can be quantified in real time in critically injured patients. It is a surrogate for cumulative hypoperfusion and it predicts high-volume transfusions and organ dysfunction.

Large-magnitude Pelvic and Retroperitoneal Tissue Damage Predicts Organ Failure

BackgroundPelvic and retroperitoneal trauma is a major cause of morbidity and mortality in multiply injured patients. The Injury Severity Score (ISS) has been criticized for underrepresenting and inaccurately defining mechanical injury. The influence of pelvic injury volume on organ dysfunction and multiple organ failure (MOF) has not been described. Through the use of CT, this investigation sought to precisely define volumes of mechanical tissue damage by anatomic region and examine its impact on organ failure.Questions/purposes(1) Do patients with MOF have a greater volume of pelvic and retroperitoneal tissue damage when compared with those without MOF? (2) In patients who sustained pelvic trauma, does the magnitude of pelvic injury differ in patients with MOF? (3) Does the magnitude of organ dysfunction correlate with pelvic tissue damage volume?MethodsSeventy-four multiply injured patients aged 18 to 65 years with an ISS ≥ 18 admitted to the intensive care unit for a minimum of 6 days with complete admission CT scans were analyzed. Each identifiable injury in the head/neck, chest, abdomen, and pelvis underwent volumetric determination using CT to generate regional tissue damage volume scores. Primary outcomes were the development of MOF as measured by the Denver MOF score and the degree of organ dysfunction by utilization of the Sequential Organ Failure Assessment (SOFA) score. Mean pelvic and retroperitoneal tissue damage volumes were compared in patients who developed MOF and those who did not develop MOF using Student’s t-test. Among patients who sustained pelvic injuries, we compared mean volume of tissue damaged in patients who developed MOF and those who did not. We assessed whether there was a correlation between organ dysfunction, as measured by the SOFA score as a continuous variable, and the volume of pelvic and retroperitoneal tissue damage using the Pearson product-moment correlation coefficient.ResultsThe average volume of tissue damage was greater in patients with MOF when compared with those without (MOF: 685.667 ± 1081.344; non-MOF: 195.511 ± 381.436; mean difference 490.156 cc [95% confidence interval {CI}, 50.076–930.237 cc], p = 0.030). Among patients who sustained pelvic injuries, those with MOF had higher average tissue damage volumes than those without MOF (MOF: 1322.000 ± 1197.050; non-MOF: 382.750 ± 465.005; mean difference 939.250 [95% CI, 229.267–1649.233], p = 0.013). Organ dysfunction (SOFA score) correlated with higher volumes of pelvic tissue damage (r = 0.570, p < 0.001).ConclusionsThis investigation demonstrated that greater degrees of pelvic and retroperitoneal tissue damage calculated from injury CT scans in multiply injured patients is associated with more severe organ dysfunction and an increased risk of developing MOF. Early identification of polytrauma patients at risk of MOF allows clinicians to implement appropriate resuscitative strategies early in the disease course. Improved stratification of injury severity and a patient’s anticipated clinical course may aid in the planning and execution of staged orthopaedic interventions. Future avenues of study should incorporate the ischemic/hypoperfusion component of pelvic injury in conjunction with the mechanical component presented here for improved stratification of multiply injured patients at higher risk of MOF.Level of EvidenceLevel III, prognostic study.