Protective Effect of Phosphatidylserine Blockade in Hemorrhagic Shock.

BACKGROUND: Phosphatidylserine (PS) is a key cell membrane phospholipid normally maintained on the inner cell surface but externalizes to the outer surface in response to cellular stress. We hypothesized that PS exposure mediates organ dysfunction in hemorrhagic shock. Our aims were to evaluate PS blockade on (1) pulmonary, (2) renal, and (3) gut function, as well as (4) serum lysophosphatidic acid (LPA), an inflammatory mediator generated by PS externalization, as a possible mechanism mediating organ dysfunction. MATERIALS AND METHODS: Rats were either (1) monitored for 130 min (controls, n = 3), (2) hemorrhaged then resuscitated (hemorrhage only group, n = 3), or (3) treated with Diannexin (DA), a PS blocking agent, followed by hemorrhage and resuscitation (DA + hemorrhage group, n = 4). Pulmonary dysfunction was assessed by arterial partial pressure of oxygen, renal dysfunction by serum creatinine, and gut dysfunction by mesenteric endothelial permeability (LP). LPA levels were measured in all groups. RESULTS: Pulmonary: there was no difference in arterial partial pressure of oxygen between groups. Renal: after resuscitation, creatinine levels were lower after PS blockade with DA versus hemorrhage only group (P = 0.01). Gut: LP was decreased after PS blockade with DA versus hemorrhage only group (P < 0.01). Finally, LPA levels were also lower after PS blockade with DA versus the hemorrhage only group but higher than the control group (P < 0.01). CONCLUSIONS: PS blockade with DA decreased renal and gut dysfunction associated with hemorrhagic shock and attenuated the magnitude of LPA generation. Our findings suggest potential for therapeutic targets in the future that could prevent organ dysfunction associated with hemorrhagic shock.

Lactate predicts massive transfusion in hemodynamically normal patients.

BACKGROUND: Trauma patients at risk of deterioration because of occult injury may be hemodynamically normal on arrival. Early identification of these patients may improve care, especially for those who require massive transfusion (MT). We hypothesized that elevated admission lactate would predict the need for MT in hemodynamically normal patients. MATERIALS AND METHODS: All trauma patients treated at our university-based urban center over a 5-year period were reviewed. We included hemodynamically normal patients who had an admission lactate performed. First, a receiver-operating curve was used to determine the threshold lactate value. Subsequent analyses were then based on this value. Variables were analyzed using chi-square and unpaired t-tests, and univariable and multivariable regressions. RESULTS: There were 3468 hemodynamically normal patients with an admission lactate. Those who received MT (n = 19) had higher lactate than those who did not (n = 3449; 5.6 versus 2.6 mmol/L, P ≤ 0.001). Receiver-operating curve curve analysis revealed a threshold lactate value of 4 mmol/L with an area under the curve of 0.71. Patients with a lactate of >4 mmol/L had increased mortality (8% versus 2%), longer hospital length of stay (LOS, 6 versus 3 days), longer intensive care unit (ICU) LOS (6 versus 3 days), greater need for MT (2.8% versus 0.3%), and greater blood requirement (219 versus 38 mL; all P values < 0.001). After controlling for confounding variables, the predictive value of admission lactate >4 remained strong (odds ratio, 5.2; 95% confidence interval, 1.87-14.2). CONCLUSIONS: In hemodynamically normal trauma patients, the admission lactate of >4 mmol/L is a robust predictor of MT requirement and associated with poor outcomes.

Single-stage revision from gastric band to gastric bypass or sleeve gastrectomy: 6- and 12-month outcomes.

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) is increasingly requiring revisional surgery for complications and failures. Removal of the band and conversion to either laparoscopic Roux-en-y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) is feasible as a single-stage procedure. The objective of this study is to compare the safety and efficacy of single-stage revision from LAGB to either LRYGB or LSG at 6 and 12 months postoperatively. METHODS: Retrospective analysis was performed on patients undergoing single-stage revision between 2009 and 2014 at a single academic medical center. Patients were reassessed for weight loss and complications at 6 and 12 months postoperatively. RESULTS: Thirty-two patients underwent single-stage revision to LRYGB, and 72 to LSG. Preoperative BMIs were similar between the two groups (p = 0.27). Median length of stay for LRYGB was 3 days versus 2 for LSG (p = 0.14). Four patients in the LRYGB group required reoperation within 30 days, and two patients in the LSG group required reoperation within 30 days (p = 0.15). There was no difference in ER visits (p = 0.24) or readmission rates (p = 0.80) within 30 days of operation. Six delayed complications were seen in the LSG group with three requiring intervention. At 6 months postoperatively, percent excess weight loss (%EWL) was 50.20 for LRYGB and 30.64 for LSG (p = 0.056). At 12 months, %EWL was 51.19 for LRYGB and 34.89 for LSG (p = 0.31). There was no difference in diabetes or hypertension medication reduction at 12 months between LRYGB and LSG (p > 0.07). CONCLUSION: Single-stage revision from LAGB to LRYGB or LSG is technically feasible, but not without complications. The complications in the bypass group were more severe. There was no difference in readmission or reoperation rates, weight loss or comorbidity reduction. Revision to LRYGB trended toward higher rate and greater severity of complications with equivalent weight loss and comorbidity reduction.

Surgeon's guide to anticoagulant and antiplatelet medications part two: antiplatelet agents and perioperative management of long-term anticoagulation.

An increasing number of potent antiplatelet and anticoagulant medications are being used for the long-term management of cardiac, cerebrovascular, and peripheral vascular conditions. Management of these medications in the perioperative and peri-injury settings can be challenging for surgeons, mandating an understanding of these agents and the risks and benefits of various management strategies. In this two part review, agents commonly encountered by surgeons in the perioperative and peri-injury settings are discussed and management strategies for patients on long-term antiplatelet and anticoagulant therapy reviewed. In part one, we review warfarin and the new direct oral anticoagulants. In part two, we review antiplatelet agents and assessment of platelet function and the perioperative management of long-term anticoagulation and antiplatelet therapy.

A surgeon's guide to anticoagulant and antiplatelet medications part one: warfarin and new direct oral anticoagulant medications.

An increasing number of potent antiplatelet and anticoagulant medications are being used for the long-term management of cardiac, cerebrovascular, and peripheral vascular conditions. Management of these medications in the perioperative and peri-injury settings can be challenging for surgeons, mandating an understanding of these agents and the risks and benefits of various management strategies. In this two-part review, agents commonly encounter by surgeons in the perioperative and peri-injury settings are discussed and management strategies for patients on long-term antiplatelet and anticoagulant therapy reviewed. In part I, we review warfarin and the new direct oral anticoagulants. In part II, we review antiplatelet agents and assessment of platelet function and the perioperative management of long-term anticoagulant and antiplatelet therapy.

Should uncooperative trauma patients with suspected head injury be intubated?

In trauma patients with a suspicion for traumatic brain injury (TBI), a head computed tomography (CT) scan is imperative. However, uncooperative patients often cannot undergo imaging without sedation and may need to be intubated. Our hypothesis was that among mildly injured trauma patients, in whom there is a suspicion of a head injury, uncooperative patients have higher rates of TBI and intubation should be considered to obtain a CT scan. We found that uncooperative patients intubated for diagnostic purposes were more likely to have moderate to severe TBI than nonintubated patients (21.4 vs. 8.4%, P < 0.0001) and uncooperative behavior leading to intubation was an independent predictor of TBI (odds ratio, 2.5; 95% confidence interval, 1.5 to 4.5). Of patients with brain injury, intubated patients more often had a head abbreviated injury scale score of 4 (20.8 vs. 7.9%, P = 0.04). Uncooperative intubated patients had longer hospital stays (3.6 vs. 2.6 days, P = 0.003) and higher mortality (0.9 vs. 0.2%, P = 0.02) than nonintubated patients. Uncooperative behavior may be an early warning sign of TBI and the trauma surgeon should consider intubating uncooperative trauma patients if there is suspicion for brain injury based on the mechanism of their trauma.

Effect of surgery resident change of shift on trauma resuscitations and outcomes.

INTRODUCTION: The ability of surgery residents to provide continuity of care has come under scrutiny with work hour restrictions. The impact of the surgery resident sign-out period (6-8am and 6-8pm) on trauma outcomes remains unknown. We hypothesize that during shift change, resuscitation times are prolonged with worse outcomes. METHODS: Records of patients treated at a university-based urban trauma center during 2008 and 2009 were reviewed. Patients were separated into a shift change group (6-8am and 6-8pm) and a control group of all other time periods and compared using ANOVA, chi square, and unpaired t-tests. RESULTS: We reviewed the charts of 4361 consecutive trauma patients. There was no difference in gender, acuity, resuscitation times, Glasgow Coma Scale, revised trauma score, injury severity score (ISS), or probability of survival score between patients arriving during shift change compared to other times (p>0.2). There was no difference in total emergency department time for patients arriving during shift change (p = 0.07), even when stratified by ISS (ISS<15, p = 0.09; ISS>15, p = 0.2). Length of stay was increased for patients arriving during shift change compared to other times (5 vs 4 days, p<0.05). This was more pronounced for those with ISS>15 (16 vs 11 days, p = 0.03); however, there was no impact on intensive care unit length of stay, ventilator days, and mortality (p>0.3) regardless of ISS. CONCLUSIONS: Trauma outcomes are generally unaffected by patient arrival during shift change when resident sign-outs occur. Although adaptations are being made to accommodate trauma patient arrival during these times, we need to continue paying close attention, especially to seriously injured patients, to ensure that there are no delays in care that may potentially affect patient outcomes.

Death or dialysis? The risk of dialysis-dependent chronic renal failure after trauma nephrectomy.

Although renal trauma is increasingly managed nonoperatively, severe renovascular injuries occasionally require nephrectomy. Long-term outcomes after trauma nephrectomy are unknown. We hypothesized that the risk of end-stage renal disease (ESRD) is minimal after trauma nephrectomy. We conducted a retrospective review of the following: 1) our university-based, urban trauma center database; 2) the National Trauma Data Bank (NTDB); 3) the National Inpatient Sample (NIS); and 4) the U.S. Renal Data System (USRDS). Data were compiled to estimate the risk of ESRD after trauma nephrectomy in the United States. Of the 232 patients who sustained traumatic renal injuries at our institution from 1998 to 2007, 36 (16%) underwent a nephrectomy an average of approximately four nephrectomies per year. The NTDB reported 1780 trauma nephrectomies from 2002 to 2006, an average of 356 per year. The 2005 NIS data estimated that in the United States, over 20,000 nephrectomies are performed annually for renal cell carcinoma. The USRDS annual incidence of ESRD requiring hemodialysis is over 90,000, of which 0.1 per cent (100 per year) of renal failure is the result of traumatic or surgical loss of a kidney. Considering the large number of nephrectomies performed for cancer, we estimated the risk of trauma nephrectomy causing renal failure that requires dialysis to be 0.5 per cent. National data regarding the etiology of renal failure among patients with ESRD reveal a very low incidence of trauma nephrectomy (0.5%) as a cause; therefore, nephrectomy for trauma can be performed with little concern for long-term dialysis dependence.

Confronting the chronically anticoagulated, acute care surgery patient as we evolve into the post-warfarin era.

There are a growing number of new anticoagulants used as an alternative to warfarin. Surgeons will be confronted with an increasing number of patients who may be on these outpatient medications and must be familiar with their management strategies. The purpose of this review is to examine the mechanisms, monitoring and therapeutic reversal of the non-warfarin antithrombotic agents now so frequently confronting the acute care surgeon.

Bedside thoracic ultrasonography of the fourth intercostal space reliably determines safe removal of tube thoracostomy after traumatic injury.

BACKGROUND: Thoracic ultrasonography is more sensitive than chest radiography (CXR) in detecting pneumothorax; however, the role of ultrasonography to determine resolution of pneumothorax after thoracostomy tube placement for traumatic injury remains unclear. We hypothesized that ultrasonography can be used to determine pneumothorax resolution and facilitate efficient thoracostomy tube removal. We sought to compare the ability of thoracic ultrasonography at the second through fifth intercostal space (ICS) to detect pneumothorax with that of CXR and determine which ICS maximizes the positive and negative predictive value of thoracic ultrasonography for detecting clinically relevant pneumothorax resolution. METHODS: A prospective, blinded clinical study of trauma patients requiring tube thoracostomy placement was performed at a university-based urban trauma center. A surgeon performed daily thoracic ultrasonographies consisting of midclavicular lung evaluation for pleural sliding in ICS 2 through 5. Ultrasonography findings were compared with findings on concurrently obtained portable CXR. RESULTS: Of the patients, 33 underwent 119 ultrasonographies, 109 of which had concomitant portable CXR results for comparison. Ultrasonography of ICS 4 or 5 was better than ICS 2 and 3 at detecting a pneumothorax, with a positive predictive value of 100% and a negative predictive value of 92%. The positive and negative predictive values for ICS 2 were 46% and 93% and for ICS 3 were 63% and 92%, respectively. CONCLUSION: Bedside, surgeon-performed, thoracic ultrasonography of ICS 4 for pneumothorax can safely and efficiently determine clinical resolution of traumatic pneumothorax and aid in the timely removal of thoracostomy tubes. LEVEL OF EVIDENCE: Diagnostic study, level II.

Does gastric volume in trauma patients identify a population at risk for developing pneumonia and poor outcomes?

BACKGROUND: Trauma patients may have full stomachs or impaired airway reflexes that place them at risk for aspiration and pneumonia. Our hypothesis was that trauma patients with larger gastric volumes as measured by abdominal computed tomography (CT) at admission have higher rates of pneumonia and worse outcomes. METHODS: We matched an initial cohort of 81 trauma patients with an admission CT of the abdomen and a diagnosis of pneumonia by Injury Severity Score and Abbreviated Injury Score of the head and chest with a control group of 81 trauma patients without pneumonia. We estimated gastric volumes on CT and compared variables using chi-square, t-tests, receiver operating curve analysis, and regression analysis. RESULTS: Patients with pneumonia had larger gastric volumes than those without pneumonia (879 cm(3)versus 704 cm(3); P = 0.04). Receiver operating curve analysis gave a gastric volume threshold value of 700 cm(3) as a predictor of pneumonia. Patients with a gastric volume ≥ 700 cm(3) had more pneumonia (61% versus 41%; P = 0.01), stayed longer in the hospital (27.6 versus 19.7 d; P < 0.05) and the intensive care unit (18.4 versus 12.5 d; P = 0.01), required more days on the ventilator (18.1 versus 12.0 d; P = 0.02), and had a trend toward increased mortality (17% versus 11%; P = 0.2). On multivariate analysis, nasogastric or orogastric tube (odds ratio 3.0; P = 0.004) and gastric volume >700 cm(3) (odds ratio 2.7; P = 0.004) were independent predictors of pneumonia. CONCLUSIONS: Trauma patients who developed pneumonia had larger initial gastric volumes. A straightforward estimate of gastric volume on admission abdominal CT may predict patients at risk for developing pneumonia and poor outcomes. Clinicians should be especially vigilant in taking precautions against pneumonia and have a lower threshold for suspecting pneumonia in patients with abdominal CT gastric volumes ≥ 700 cm(3).

The heart of the matter: utility of ultrasound of cardiac activity during traumatic arrest.

BACKGROUND: The clinical utility of determining cardiac motion on ultrasound has been reported for patients presenting in pulseless medical cardiac arrest. However, the relationship between ultrasound-documented cardiac activity and the probability of surviving pulseless electrical activity has not been examined in populations with trauma. We hypothesized that cardiac activity on ultrasound predicts survival for patients presenting in pulseless traumatic arrest. METHODS: We conducted a retrospective analysis at our university-based urban trauma center of adult patients with trauma, who were pulseless on hospital arrival. Results of cardiac ultrasound performed during trauma resuscitations were compared with the electrocardiogram (EKG) rhythm and survival. RESULTS: Among 318 pulseless patients with trauma, 162 had both EKG tracings and a cardiac ultrasound, and 4.3% of these 162 patients survived to hospital admission. Survival was higher for those with cardiac motion than for those without it (23.5% vs. 1.9% for patients with EKG electrical activity, p = 0.002, and 66.7% vs. 0% for patients without EKG electrical activity, p < 0.001). The sensitivity of ultrasound cardiac motion to predict survival to hospital admission was 86% (specificity, 91%; positive predictive value, 30%; negative predictive value, 99%). When examined by mechanism, sensitivity was 100% for the 111 patients with penetrating trauma and 75% for the 50 patients with blunt trauma. CONCLUSION: Survival in pulseless traumatic arrest is very low, but survival for patients with no cardiac motion on ultrasound is also exceedingly rare. Cardiac ultrasound had a negative predictive value approaching 100% for survival to hospital admission. For patients with prolonged prehospital cardiopulmonary resuscitation, ultrasound evaluation of cardiac motion in pulseless patients with trauma may be a rapid way to help determine which patients have no chance of survival in the setting of lethal injuries, so that futile resuscitations can be stopped.

Emergency uncrossmatched transfusion effect on blood type alloantibodies.

BACKGROUND: Trauma patients receive emergency transfusions of unmatched Type O Rh-negative (Rh-) blood until matched blood is available. We hypothesized that patients given uncrossmatched blood may develop alloantibodies, placing them at risk for hemolytic transfusion reactions (HTRs). METHODS: Data regarding alloantibody profiles and HTR occurrence were collected from the records of trauma patients at our university-based trauma center who received emergency uncrossmatched blood from July 2008 to August 2010. RESULTS: A total of 132 patients received 1,570 units of packed red blood cells. Mean injury severity score was 28 ± 1.3. Forty-five (34%) patients died: 27 on hospital day 1; the remaining 18 had no evidence of HTR before death. Four Rh- female patients received Rh+ fresh frozen plasma, but none received Rh+ packed red blood cells. Three Rh- male patients received both Rh+ packed red blood cells and fresh frozen plasma, and one received Rh+ fresh frozen plasma. One patient developed anti-Rh D antibodies. None experienced HTR. One female patient had HTR from reactivation of anamnestic JK antibodies. Thirteen (33%) of 39 patients met criteria for HTR based on urinalysis and 29 (40%) of 72 patients tested met criteria for HTR based on hemoglobin and bilirubin values. Only one patient had confirmed HTR. CONCLUSION: High rates of injury recidivism in trauma patients increase the likelihood of multiple blood transfusions during their lifetime. Rh- patients who receive Rh+ blood are at risk of developing anti-Rh antibodies, putting them at risk for HTR. The conservation of Rh- blood for use in female patients may be detrimental to Rh- male patients. Laboratory diagnostic criteria for HTR are nonspecific in the trauma population and should be used with caution.

A novel CT volume index score correlates with outcomes in polytrauma patients with pulmonary contusion.

BACKGROUND: Exact quantification of pulmonary contusion by computed tomography (CT) may help trauma surgeons identify high-risk populations. We hypothesized that the size of pulmonary contusions, measured accurately, will predict outcomes. Our specific aims were to (1) precisely quantify pulmonary contusion size using pixel analysis, (2) correlate contusion size with outcomes, and (3) determine the threshold contusion size portending complications. METHODS: Thoracic CTs of 106 consecutive polytrauma patients with pulmonary contusion were evaluated at a university-based urban trauma center. A novel CT volume index (CTVI) score was calculated based on the ratio of affected lung to total lung [slices of lung on CT × affected pixel region/lung pixel region × 0.45 (left side) + slices of lung on CT × affected pixel region/lung pixel region × 0.55 (right side)]. Multivariate analysis correlated CTVI and patient predictors' impact on outcomes. RESULTS: Of 106 polytrauma patients (mean ISS = 28 ± 1.2, AIS chest = 3.5 ± 0.1), 39 developed complications (acute respiratory distress syndrome [ARDS], pneumonia, and/or death). Mean CTVI was significantly higher in the group with complications (0.28 ± 0.03 versus 17 ± 0.02, P = 0.01). By multivariate analysis, CTVI predicted longer ICU LOS (R(2) = 0.84, P < 0.01). A receiver operating curve (ROC) analysis identified a CTVI threshold score of 0.2 (AUC 0.67, P < 0.01) for developing pneumonia, ARDS or death. Patients with CTVI scores of 0.2 or more had longer hospitalization, longer ICU LOS, more ventilator days, and developed pneumonia (P < 0.01). CONCLUSIONS: Higher CTVI scores predicted prolonged ICU LOS across all sizes of pulmonary contusion. Pulmonary contusion volumes greater than 20% of total lung volume specifically identifies patients at risk for developing complications.

Correlation between IVC dimensions and volume status on CT scan.

BACKGROUND: End points of resuscitation in trauma patients are difficult to define. The size of the inferior vena cava (IVC) on CT scan may accurately indicate volume status and guide resuscitation efforts. Our hypothesis was that IVC "flatness" on CT scan reflects volume status in hemodynamically normal trauma patients. METHODS: The study population was drawn from a database of trauma patients who had abdominal CT scans and lactate levels drawn on arrival. Lactate was chosen as a marker of volume status since hypotensive patients were unlikely to undergo CT. Anteroposterior (AP) and transverse (TV) diameters of the IVC were measured at the suprarenal and infrarenal locations. A flatness index was calculated for each location (TV ÷ AP) and this value was correlated with heart rate, blood pressure, and lactate. RESULTS: There was no difference in IVC flatness at the suprarenal or infrarenal position for patients with an elevated lactate compared with those with a normal lactate: 1.54 ± 0.18 versus 1.43 ± 0.08 (P = 0.2) suprarenal and 1.54 ± 0.46 versus 1.68 ± 0.58 (P = 0.4) infrarenal. IVC flatness at the suprarenal location weakly correlated with blood pressure (r = -0.29). IVC flatness did not correlate with blood pressure at the infrarenal location (r = -0.1). IVC flatness did not correlate with heart rate (P > 0.3) or age (P > 0.2). CONCLUSION: These results did not demonstrate a correlation between IVC flatness and the markers of intravascular volume of heart rate, blood pressure, or lactate. IVC flatness on CT scan is not a valid indicator of volume status in hemodynamically normal trauma patients.

Timing is everything: delayed intubation is associated with increased mortality in initially stable trauma patients.

BACKGROUND: The indications for immediate intubation in trauma are not controversial, but some patients who initially appear stable later deteriorate and require intubation. We postulated that initially stable, moderately injured trauma patients who experienced delayed intubation have higher mortality than those intubated earlier. METHODS: Medical records of trauma patients intubated within 3 h of arrival in the emergency department at our university-based trauma center were reviewed. Moderately injured patients were defined as an ISS < 20. Early intubation was defined as patients intubated from 10-24 min of arrival. Delayed intubation was defined as patients intubated ≥25 min after arrival. Patients requiring immediate intubation, within 10 min of arrival, were excluded. RESULTS: From February 2006 to December 2007, 279 trauma patients were intubated in the emergency department. In moderately injured patients, mortality was higher with delayed intubation than with early intubation, 11.8% versus 1.8% (P = 0.045). Patients with delayed intubations had greater frequency of rib fractures than their early intubation counterparts, 23.5% versus 3.6% (P = 0.004). Patients in the delayed intubation group had lower rates of cervical gunshot wounds than the early intubation group, 0% versus 10.7% (P = 0.048) and a trend toward fewer of skull fractures 2.9% versus 16.1%, (P = 0.054). CONCLUSIONS: These findings suggest that delayed intubation is associated with increased mortality in moderately injured patients who are initially stable but later require intubation and can be predicted by the presence of rib fractures.

Sonographic optic nerve sheath diameter as an estimate of intracranial pressure in adult trauma.

BACKGROUND: Intracranial pressure (ICP) is currently measured with invasive monitoring. Sonographic optic nerve sheath diameter (ONSD) may provide a noninvasive estimate of ICP. Our hypothesis was that bedside ONSD accurately estimates ICP in acutely injured patients. The specific aims were (1) to determine the accuracy of ONSD in estimating elevated ICP, (2) to correlate ONSD and ICP in unilateral and bilateral head injuries, and (3) to determine the effect of ICP monitor placement on ONSD measurements. MATERIALS AND METHODS: A blinded prospective study of adult trauma patients requiring ICP monitoring was performed at a University-based urban trauma center. The ONSD was measured by ultrasound pre- and post-placement of an ICP monitor (Camino Bolt or Ventriculostomy). RESULTS: One-hundred fourteen measurements were obtained in 10 trauma patients requiring ICP monitoring. Pre- and post-ONSD were compared with side of injury in the presence of an ICP monitor. ROC analysis demonstrated ONSD poorly estimates elevated ICP (AUC = 0.36). Overall sensitivity, specificity, PPV, NPV, and accuracy for estimating ICP with ONSD were 36%, 38%, 40%, 16%, and 37%. Poor correlation of ONSD to ICP was observed with unilateral (R(2) = 0.45, P < 0.01) and bilateral (R(2) = 0.21, P = 0.01) injuries. ICP monitor placement did not affect ONSD measurements on the right (P = 0.5), left (P = 0.4), or right and left sides combined (P = 0.3). CONCLUSIONS: Sonographic ONSD as a surrogate for elevated ICP in lieu of invasive monitoring is not reliable due to poor accuracy and correlation.

Endovascular retrieval of inferior vena cava filter penetrating into aorta: an unusual presentation of abdominal pain.

Inferior vena cava filters are commonly used in patients with contraindications to or failures of treatment with anticoagulation. However, these are not without complications. Serious complications include penetration of the filter struts into adjacent structures, including the aorta. The design of permanent filters makes retrieval in the instance of life-threatening complication complex, often requiring extensive surgical exploration. Retrievable filters may be more easily removed via endovascular methods, reducing the morbidity of surgical approaches.