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No consensus exists regarding duration of antibiotic therapy for complicated appendicitis treated with interval appendectomy. We hypothesized that more than two weeks of antibiotic therapy does not decrease complication rates in asymptomatic patients.A retrospective review of all patients with complicated appendicitis treated with interval appendectomy from 2010-2015 was performed. We divided the patients in two groups (group 1, ≤2 weeks of antibiotics; group 2:2 weeks of antibiotics). Demographics, antibiotic agents, and complications were collected. Pearson χ analysis and Student t-test analysis was performed with significance of p 0.05.Total of 158 patients met inclusion criteria (group 1 [47.4%] vs. group 2 [52.5%]). Mean length of stay was 7.5 days. Abscess on admission was 26% (n = 41). The groups were demographically similar. Total complication rate was 39.2% (abscess development, n = 19; re-admissions, n = 16; interval appendectomy28 days, n = 13; unplanned emergency department visits, n = 7; fistula, n = 4, wound infection/dehiscence, n = 3; and conversion to open surgery, n = 4). All fistulas and conversions occurred in the less than two-week group. Mean course of antibiotics was 4.1 weeks. There was no significant difference in the complication rates based on duration or type of antibiotics (p = 1.0).Treatment with more than two weeks of antibiotic therapy for complicated appendicitis does not confer any clinical benefit prior to interval appendectomy. Complications were not reduced by a prolonged course of antibiotic therapy.

Introduction: Although rare, major complications after gastrostomy tube placement are a significant source of morbidity in children. The purpose of this study was to identify predictors of...

BACKGROUND Pediatric trauma patients transferred to pediatric trauma centers (PTCs) often have imaging at the originating hospital (OH). The increased use of computed tomography (CT) raises concerns about malignancy risk from ionizing radiation leading many PTCs to adopt radiation dose reduction strategies. We hypothesized that pediatric trauma patients are exposed to excess radiation from imaging before transfer. METHODS A retrospective review of 1,383 scans was performed on all trauma patients with CT imaging before transfer to our Level I PTC from 2010 to 2014. Demographics, type of imaging, necessity for repeat imaging, appropriateness of imaging, and radiation dose delivered were recorded. Comparative radiation dosing was calculated using the dose-length product (DLP [expressed in mGy-cm]). All CT scans except for CT of the abdomen and pelvis and CT of the head were excluded for complete DLP data issues. Scans were considered clinically appropriate if they met Advanced Trauma Life Support (ATLS) recommendations (ATLS+) and not indicated if they did not meet ATLS criteria (ATLS-). Some scans were repeated because of technical issues. Median ΔDLP represents the difference in dose patients received at OH versus at PTC. RESULTS A total of 673 patients were analyzed. Average age was 11 years, and 65.4% were male. Mean DLP at PTC was 54% lower for all analyzed scans compared with OH (p < 0.0001). DLP at PTC was 51% lower for CT of the abdomen and pelvis and 62% lower for CT of the head. Children received excess dose of 578.62 mGy-cm for scans at OH that were unnecessary. For ATLS+ imaging, children received a median excess of 444.42 mGy-cm of radiation at OH than they would have received had the scans been performed at PTCs using pediatric radiation reduction strategies. CONCLUSION Pediatric trauma imaging performed at transferring institutions often does not adhere to ATLS recommendations and exceeds required ionizing radiation dosages. This study further confirms ATLS recommendations supporting prompt patient transfer without delay for imaging. LEVEL OF EVIDENCE Therapeutic study, level IV.

The standard practice in pediatric patients diagnosed with intussusception has been reduction via enema and admission for a period of nil per os and observation. Little data exists to support this practice. The objective of this study was to examine whether post-reduction admission to hospital is required.A retrospective chart review was performed on all patients aged 0-18 years old with intussusception over a span of 20 years. Study included children treated for intussusception on first encounter with enema and subsequently admitted for observation. Study excluded those readmitted for recurrence after 48 h, patients whose intussusception did not reduce on first try, those lost to follow-up, and those who went to the operating room. Early recurrence was defined as recurrence within 48 h post-reduction.Out of 171 patients admitted, only one experienced an early recurrence (0.6 %). Median length of stay for all patients was 2 days. Average cost incurred per day for intussusception admission was $404.Intussusception in a child that is successfully reduced via enema has a low recurrence rate and is usually followed by prompt resolution of symptoms. An abbreviated period of observation in the emergency department post-reduction may result in healthcare savings.

Peptic ulcer disease (PUD) is a rare condition in children. Perforated peptic ulcer (PPU), a complication of PUD has an estimated mortality between 1.3% and 20%. We evaluate incidence and outcomes of PPU in children using an administrative database, perform a review of the literature, and report our technique for laparoscopic omental patch repair for PPU in two pediatric patients.Kids' inpatient database (KID's) was analyzed for demographics, incidence, and outcomes. Incidence for each year was calculated based on the reported pediatric population in the United States for 2000, 2003, 2006, 2009, and 2012 by the U.S. Census Bureau. Additionally, we present two PPU cases, accompanied by a comprehensive review of the literature.The annual number of primary discharge diagnosis of PPU in the KID was 178 cases for 2000, 252 for 2003, 255 for 2006, 299 for 2009, and 266 for 2012. An increase trend over time was noted between 2000 and 2009; however, it was not statistically significant (0.05). PPU appears to be more common in Caucasian teenage boys. The mean length of stay was 8.02 days and with a statistically significant increase in healthcare charges ($33,187 versus $78,142, P = .002) when comparing year 2000-2012.PPU is a rare cause of abdominal pain in children, but still a PUD complication that requires surgery. PPU should be included in the differential diagnosis in patients presenting with acute abdominal pain of uncertain etiology and pneumoperitoneum. Laparoscopy is both diagnostic and therapeutic. Laparoscopic omental patch repair is a safe and effective treatment for PPUs.

Background Contemporary war-related studies focus primarily on adults with few reporting the injuries sustained in local pediatric populations. The objective of this study is to characterize pediatric vascular trauma at US military hospitals in wartime Iraq and Afghanistan. Methods Review of the Department of Defense Trauma Registry (DoDTR) (2002–2011) identified patients (1–17years old) treated at US military hospitals in Iraq and Afghanistan using ICD-9 and procedure codes for vascular injury. Results US military hospitals treated 4402 pediatric patients between 2002 and 2011. One hundred fifty-five patients (3.5%) had a vascular injury. Mean age, gender, and injury severity score (ISS) were 11.1±4.1years, 79% male, and 34±13.5, respectively. Vascular injuries were primarily from penetrating mechanisms (95.6%; 58.0% blast injury) to the extremity (65.9%), torso (25.4%), and neck (8.6%). Injuries were ligated (31%), reconstructed (63%), or observed (2%). Limb salvage rate was 95%. Mortality rate was 9%. Conclusions This study is the first to report vascular trauma in a pediatric population at wartime. Vascular injuries involve a high percentage of extremity and torso wounding. Torso vascular injury in children is four times lethal relative to other injury patterns, and therefore should be considered in operational planning both in the military and civilian setting regarding pediatric vascular injuries.

Computed tomography (CT) for pediatric traumatic brain injury (TBI) is common. Evidence suggests that 1 in 1,200 children undergoing CT will die of malignancy from radiation exposure. Presently, there is no protocol for surveying children with mild TBI; repeat CT (rCT) is often performed. We hypothesized that rCT could be avoided. Outcomes of similar patients who underwent rCT were compared with those of patients followed by clinical examination alone.An 8-year retrospective review was performed of patients admitted to a Level I pediatric trauma center with TBI, CT evidence of TBI, and Glasgow Coma Scale (GCS) score of 14 to 15. There were two groups, those who underwent rCT (rCT+) and those who did not (rCT-). Data included age, Injury Severity Score (ISS), mechanism of injury, type of TBI, and outcome. Patients with coagulopathies, ventriculoperitoneal shunts, developmental disabilities, nonaccidental trauma, concomitant injuries, or medical problems resulting in intubation or sedation not attributed to TBI were excluded.Of 391 patients admitted with TBI, 120 were included in the study. A total of 106 patients were rCT+, and 14 were rCT-. rCT+ children were older (mean, 98.7 ± 7.3 vs. 35.3 ± 11.5 months; p = 0.0025) and more likely to have epidural hematoma (EDH) (100% rCT with EDH vs. 76% rCT all other TBI, p = 0.044). Mechanism of injury and mean ISS (15.2 ± 0.6 vs. 13.0 ± 1.1, p = 0.195) were not different between the groups. There were no worsening neurologic symptoms or need for surgery in rCT- children. rCT identified seven patients (6.6%) with CT progression of their injury. Five had an EDH, and two had a subarachnoid hemorrhage. Two children with EDH underwent operation.Our study indicates that routine rCT without evidence of clinical deterioration is not indicated in children with admission GCS score of 14 to 15 and TBI on CT scan. Children with EDH seem to have a higher potential for progression, and rCT seems to be indicated in this subgroup.Therapeutic study, level IV.

The clinical scenario of a neurologically impaired child with a prolonged history of gastroesophageal reflux disease that underwent open Roux-en-Y gastrojejunostomy with subsequent development of severe symptomatic bile reflux is reported. The presentation, evaluation, and surgical management by laparoscopic revision to a modified esophagogastric dissociation are discussed.

Intercostal hernia can occur after blunt trauma and can also complicate thoracotomy. This report describes a 13-year-old liver transplant recipient with chronic asymptomatic intercostal hernia at site of thoracotomy. This hernia became manifest upon development of spontaneous pneumothorax. She presented with pleuritic pain and radiographic evidence of spontaneous pneumothorax. Her history included liver transplantation at age 19 months for tyrosinemia, posttransplant lymphoproliferative disorder at age 7 years with thoracotomy for lung biopsy, and prolonged corticosteroid administration. Examination and computed tomography revealed an intercostal hernia. She underwent repair of hernia, stapled resection of apical blebs, and pleurodesis. Reconstruction of chest wall involved rib fracture and intercostal approximation with nonabsorbable sutures covered by serratus muscle advancement. She is symptom free with intact repair 2 years and 9 months after surgery and is able to participate in vigorous physical activity. This is the first report of an intercostal hernia detected upon development of spontaneous pneumothorax. The hernia occurred at the site of a prior thoracotomy, possibly because of impaired healing from corticosteroid administration. This case suggests that nonabsorbable sutures should be used for intercostal approximation after thoracotomy in patients with impaired wound healing.

BACKGROUND: Firearm related injuries are a significant cause of morbidity and mortality in children. To determine current trends and assess avenues for future interventions, we examined the epidemiology and outcome of pediatric firearm injuries managed at our region's two major pediatric trauma centers. METHODS: Following IRB approval, we conducted a 5-year retrospective review of all pediatric firearm victims, aged ≤16 years, treated at either of the region's two Level-1 pediatric trauma centers; St. Louis Children's Hospital and Cardinal Glennon Children's Medical Center. RESULTS: There were 398 children treated over a 5-year period (2008-2013) for firearm related. Of these children, 314 were black (78.9%). Overall, there were 20 mortalities (5%). Although most patients were between 14-16 years of age (67.6%), younger victims had a greater morbidity and mortality. The majority of injuries were categorized as assault/intentional (65%) and occurred between 6pm and midnight, outside the curfew hours enforced by the city. Despite a regional decrease in the overall incidence of firearm injuries during the study period, the rate of accidental victims per year remained stable. Most accidental shootings occurred in the home (74.2%) and were self-inflicted (37.9%) or caused by a person known to the victim (40.4%). CONCLUSION: Despite a relative decrease in intentional firearm related injuries, a constant rate of accidental shootings suggest an area for further intervention. LEVEL OF EVIDENCE: 4, prognostic and epidemiological. Language: en

BACKGROUND: Increased accessibility and rapidity of computed tomography (CT) have led to increased use and radiation exposure to pediatric trauma patients. The thyroid is radiosensitive and therefore at risk for developing malignancy from radiation exposure during cervical spine CT. This analysis aimed to determine which preelementary trauma patients warrant cervical spine CT by defining incidence and clinical characteristics of preelementary cervical spine injury. METHODS: This was a retrospective review of pre-elementary trauma patients from 1998 to 2010 with cervical spine injury admitted to a Level I trauma center. Patients were identified from the trauma registry using DRG International Classification of Diseases-9th Rev. codes and reviewed for demographics, mechanism of injury, clinical presentation, injury location, injury type, treatment, and outcome. RESULTS: A total of 2,972 preelementary trauma patients were identified. Twenty-two (0.74%) had confirmed cervical spine injuries. Eleven (50%) were boys, and the mean (SD) age was 3 (1.7) years. The most common mechanism of injury was motor vehicle collision (n = 16, 73%). The majority (59%) were in extremis, and 12 (55%) arrived intubated. The median Glasgow Coma Scale (GCS) score was 3 (interquartile range, 3-10); the median Injury Severity Score (ISS) was 33 (interquartile range, 17-56). Nineteen injuries (76%) were at the level of C4 level and higher. The mortality rate was 50%. All patients had clinical findings suggestive of or diagnostic for cervical spine injury; 18 (82%) had abnormal neurologic examination result, 2 (9%) had torticollis, and 2 (9%) had neck pain. CONCLUSION: The incidence of cervical spine injury in preelementary patients was consistent with previous reports. Missing a cervical spine injury in asymptomatic preelementary patients is extremely low. Reserving cervical spine CT to symptomatic preelementary patients would decrease unnecessary radiation exposure to the thyroid. LEVEL OF EVIDENCE: Therapeutic study, level IV. Language: en

Anterior sacral meningoceles are lesions that are uncommonly reported and can be associated with other pathology including presacral masses, tethered spinal cord, and syringomyelia. Tethered spinal cord and syringomyelia can result in neurologic deficits, while large meningoceles and presacral masses can have gastroenterologic, urologic, reproductive, and oncologic consequences.The authors report a case of a 14-year-old girl with an anterior sacral meningocele, tailgut cyst, and tethered cord with holocord syringomyelia who presented with a tethered cord syndrome, manifested by constipation, urinary retention, bilateral lower extremity weakness, and sensory deficits. After extensive radiographic and urodynamic workups were performed, the patient was treated by the neurosurgery and pediatric surgery teams with a posterior sagittal approach for cord detethering, resection of an intradural cystic mass, resection of the anterior sacral meningocele, and resection of the adjacent presacral mass. After surgical treatment, motor weakness and sensory deficits were resolved, though urinary symptoms persisted. The syrinx resolved after detethering alone. Pathology of the intradural cystic mass and the presacral mass inferior to the anterior sacral meningocele were consistent with tailgut cyst.The patient's clinical and surgical management are discussed, and a literature review related to anterior sacral meningoceles and their related pathologies is presented. An interdisciplinary approach is required for the best treatment of this constellation of findings.

Purpose: The purpose of this study was to determine the effect of gender on the immediate and long-term postoperative morbidity, mortality, and patency rates for infrainguinal autogenous vein bypass grafts. Methods: Data were abstracted for consecutive patients who were followed in a prospective surveillance protocol after undergoing infrainguinal autogenous vein bypass grafting during the years 1988 to 1994. There were 165 grafts constructed in 148 patients (101 in 87 men, and 64 in 61 women). Gender differences were analyzed with Student t test or χ2 test for risk factors, indications for reconstruction, and complications. The patency rates and the long-term survival rates were compared by means of life-table analysis. Eagle criteria and long-term survival rates were compared with multivariate analysis. Results: The mean follow-up period was 36 months (39 months for men, and 32 months for women), with a range of 6 to 123 months for the total follow-up period. The two groups did not differ in age at the time of operation (66.6 ± 1.2 years for men, and 66.7 ± 1.5 years for women) or in history of diabetes (48% for men, and 56% for women). The risks were similar for hypertension (48% for men vs 45% women), preoperative myocardial infarction (23% for men vs 26% for women), and previous coronary artery bypass grafting (9% for men vs 8% for women). The thallium stress scintigraphy results showed a diagnosis of proportionately more preoperative defects in men (reversible, 34% vs 18%, P < .05; overall, 75% vs 43%, P < .05). The 30-day limb loss rates (0.9% for men, and 0% for women) and mortality rates (2.2% for men, and 5% for women) were similar. Women had statistically more perioperative myocardial infarctions than did men (6 of 61, 9.8% vs 2 of 101, 2%; P < .05), as was documented with electrocardiography and cardiac isoenzymes. Two of these women died within a 30-day postoperative period. The 3-year primary patency rate was 85% for the men and 88% for the women, and the primary assisted patency rate was 97% for the men and 97% for the women. The secondary patency rate was 98% for the men and 97% for the women. The limb salvage rate was slightly higher for the men than for the women (93% vs 87%), although this was not statistically significant. The 5-year survival rate for women was statistically less than for men, with life-table analysis (58% for men vs 42% for women; P < .05). Conclusion:After distal bypass grafting, men and women have similar rates of patency and limb salvage, but women have a higher incidence rate of perioperative myocardial infarction and a decreased 5-year survival rate. These data suggest that women have unrecognized cardiac disease that affects them adversely in the perioperative period and the long term when compared with men who undergo the same operation. (J Vasc Surg 1999;29:807-13.)

BACKGROUND Endothelial dysfunction is presumed to occur after hemorrhagic shock and resuscitation. This study uses a novel large-animal model to evaluate the effects of diverse resuscitation regimens on endothelial function. METHODS Twenty-seven adult domestic pigs (Sus scrofa) were used in this study. Control pigs (n = 3) underwent instrumentation alone. The remaining pigs experienced controlled hemorrhagic shock to a mean arterial blood pressure of 30 +/- 5 mm Hg for 45 minutes. Pigs were resuscitated to their baseline mean arterial blood pressure +/-5 mm Hg with either shed blood (SB; n = 8), lactated Ringers solution (40 mL/kg) followed by shed blood (LRSB; n = 8), or lactated Ringers solution alone (LR; n = 8). At baseline, 1 and 4 hours after resuscitation, acetylcholine (5, 10, and 15 microg/min) was infused into the proximal iliac artery to measure endothelial dependent relaxation (EDR). Sodium nitroprusside was infused to determine endothelial independent relaxation at the end of the study to insure smooth muscle vasomotor integrity. External iliac artery luminal diameter was measured using motion-mode ultrasonography. Statistical analysis was performed using repeated-measures analysis of variance with Tukey's post-hoc analysis. RESULTS All pigs survived the experiment. Pigs required ninefold more resuscitation with LR (370.58 +/- 29 mL/kg) versus SB (41.45 +/- 3.5 mL/kg) or LRSB (76.4 +/- 1.1 mL/kg) (p < 0.05). EDR for LR pigs 1 hour after initiation of resuscitation (R1) was 70.4 +/- 14.4% compared with 94.2 +/- 13.4% for SB and 106.1 +/- 8.2% for LRSB (p < 0.05). At 4 hours after resuscitation (R4), systolic luminal diameters were larger in the SB (0.45 +/- 0.01 cm) and LRSB (0.51 +/- 0.02 cm) groups compared with LR (0.41 +/- 0.03 cm) (LRSB versus LR; p = 0.01). At R4, EDR for the LR group was 78.3 +/- 10.7% compared with SB (101.4 +/- 8.3%) and LRSB (106.4 +/- 7.4%) (p < 0.05). Infusion of sodium nitroprusside confirmed integrity of smooth muscle vasorelaxation. Analysis of serum nitric oxide levels revealed decreased values after resuscitation with LR (9.44 +/- 0.76 mol/L) compared with SB (26.3 +/- 7.8 mol/L) and LRSB (16.3 +/- 1.0 mol/L) (p = not significant). CONCLUSION This is the first description of a large-animal model to evaluate EDR after hemorrhagic shock. Resuscitation with LR requires significantly larger volumes than SB or LRSB. LR resuscitation leads to endothelial dysfunction, as determined by decreased EDR, versus SB or LRSB. Resuscitation with blood products may preserve nitric oxide bioactivity when compared with crystalloid resuscitation in the setting of hemorrhagic shock.

Military guidelines call for two 500-mL boluses of Hextend for resuscitation in far-forward environments. This study compared a hemoglobin-based oxygen carrier (HBOC-201; Hemopure) to Hextend when used to treat hemorrhagic shock in situations of delayed definitive care military operations.Yorkshire swine (55-65 kg) were hemorrhaged to a mean arterial blood pressure (MAP) of 30 mmHg. Hypotension was maintained for 45 minutes followed by resuscitation with either Hextend (HEX) (n = 8) or HBOC-201 (HBOC) (n = 8). Over 8 hours, animals received up to 1,000 mL of either fluid in an effort to sustain an MAP of 60 mmHg. At the end of 8 hours, HEX animals received 2 L of lactated Ringer's solution followed by shed blood. HBOC animals received 4 L of lactated Ringer's solution only. Animals were killed and necropsied on postprocedure day 5. Hemodynamic data were collected during shock and resuscitation. Complete blood counts, amylase, lactate, coagulation studies, and renal and liver function were measured throughout the experiment.Equivalent volumes were hemorrhaged from each group (HBOC, 44.3 +/- 2.2 mL/kg; HEX, 47.4 +/- 3.0 mL/kg). The HBOC group achieved the goal MAP (HBOC, 60.0 +/- 2.3 mmHg; HEX, 46.4 +/- 2.3 mmHg; p0.01) and required less volume during the initial 8 hours (HBOC, 12.4 +/- 1.4 mL/kg; HEX, 17.3 +/- 0.3 mL/kg; p0.01). The HBOC group had lower SvO2 (HBOC, 46.3 +/- 2.4%; HEX, 50.7 +/- 2.5%; p = 0.12) and cardiac output (HBOC, 5.8 +/- 0.4 L/min; HEX, 7.2 +/- 0.6 L/min; p = 0.05), but higher systemic vascular resistance (HBOC, 821.4 +/- 110.7 dynes . s . cm-5; HEX, 489.6 +/- 40.6 dynes . s . cm-5; p = 0.01). Base excess, pH, lactate, and urine output did not differ between groups. HEX group survival was 50% (four of eight) versus 88% for the HBOC group (seven of eight). All animals survived the initial 8 hours. Animals surviving 5 days displayed no clinical or laboratory evidence of organ dysfunction in either group.HBOC-201 more effectively restored and maintained perfusion pressures with lower volumes, and allowed for improved survival. These data suggest that hemoglobin-based oxygen carriers are superior to the current standard of care for resuscitation in far-forward military operations.

l Purpose: To investigate if a decrease in internal carotid artery (ICA) blood flow occurs with bilateral brachial artery occlusion (BBO), which may improve the effectiveness of cerebral protection devices during carotid interventions. Methods: Thirty-two asymptomatic patients (21 men; mean age 67 years) with carotid atherosclerosis between 15% and 79% were enrolled in the study. Carotid duplex ultra- sound was followed by volume flow rate (VF) determination in the right ICA, external carotid (ECA), and vertebral arteries. After baseline values were obtained, BBO was in- duced by bilateral arm pressure cuff inflation to 30 mmHg over the systolic pressure for no more than 3 minutes. VF measurements were repeated. Results: Seventeen patients (responders) had an ICA VF decrease from 4066109 mL/min (6SD) to 303690 mL/min (p50.005), while 15 patients (nonresponders) had no significant change in their ICA VF (3406192 versus 4476267 mL/min, p50.22). In responders, ECA VF increased (190665 to 2326125 mL/min), as did vertebral VF (77653 to 95660 mL/min; p.0.05). The ratio of ICA/ECA VF dropped from 2.13 to 1.31 in responders, but did not change in nonresponders. No patient exhibited any neurological symptoms during the study. Post cuff volume flows approximated baseline values. Cerebral magnetic resonance angiograms obtained in 10 responders revealed a complete circle of Willis in 8 (80%), while only 1 (16%) of 6 nonresponders had a complete pathway. Conclusions: A transient decrease in ICA VF, with concomitant elevations of the ECA and vertebral VFs, occurs with occlusion of the brachial arteries in the setting of a complete circle of Willis. Since no flow reversal occurs, this maneuver is insufficient to provide complete cerebral protection, but it may improve the effectiveness of cerebral protection devices and serve as an adjunctive maneuver in selected cases. Furthermore, changes in ICA VF may prove to be a noninvasive test for evaluating the integrity of the circle of Willis. J Endovasc Ther 2005;12:454-460

The purpose of this study was to determine if a hemoglobin-based oxygen carrier, HBOC-201 (Hemopure, Biopure Corp), alters endothelial function and nitric oxide physiology when used for hemorrhagic shock.Female swine (Sus scrofa) underwent catheterization of the femoral, circumflex iliac, and pulmonary arteries. Control animals (n = 3) underwent instrumentation only. Study animals underwent hemorrhage to mean arterial pressure of 30 +/- 5 mmHg, were maintained for 45 minutes, and resuscitated to the baseline mean arterial pressure for 4 hours. Resuscitation fluids included: shed blood (SB) (n = 8), lactated Ringers plus shed blood (LRSB) (n = 8), and HBOC (n = 8). At baseline, 1, and 4 hours after resuscitation, acetylcholine was infused into the proximal iliac artery and endothelial-dependent relaxation was measured with M-mode ultrasonography. Nitric oxide levels were determined using a chemiluminescent assay.HBOC, SB, and LRSB provided equivalent survival and resuscitation as measured by mean arterial pressures (65.3 +/- 2.48 mmHg); pulmonary artery mean pressures (15.8 +/- 0.84 mmHg); and lactate levels (1.22 +/- 0.19 mmol/L). HBOC group animals required the lowest resuscitation volume (SB, 41.5 +/- 3.5 mL/kg; LRSB, 76.4 +/- 1.1 mL/kg, HBOC, 14.6 +/- 2.1 mL/kg, p0.001). Response to acetylcholine was normal in the SB and LRSB groups, but the HBOC group had diminished acetylcholine response (29.5% endothelial-dependent relaxation end resuscitation, p0.001). Arterial nitric oxide levels did not differ between study groups (p = 0.69).HBOC might be an alternative resuscitation agent in patients with hemorrhagic shock. Resuscitation with HBOC requires less volume than blood or crystalloid. These data suggest HBOC-201 has a vasoconstrictive effect that cannot be attributed soley to nitric oxide scavenging.