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Dive into the research topics where Raymond Tatevossian is active.

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Featured researches published by Raymond Tatevossian.


Annals of Surgery | 2000

Endpoints of resuscitation of critically injured patients: normal or supranormal? A prospective randomized trial.

George C. Velmahos; Demetrios Demetriades; William C. Shoemaker; Linda S. Chan; Raymond Tatevossian; Charles C. J. Wo; Edward E. Cornwell; James Murray; Bradley Roth; Howard Belzberg; Juan A. Asensio; Thomas V. Berne

ObjectiveTo evaluate the effect of early optimization in the survival of severely injured patients. Summary Background DataIt is unclear whether supranormal (“optimal”) hemodynamic values should serve as endpoints of resuscitation or simply as markers of the physiologic reserve of critically injured patients. The failure of optimization to produce improved survival in some randomized controlled trials may be associated with delays in starting the attempt to reach optimal goals. There are limited controlled data on trauma patients. MethodsSeventy-five consecutive severely injured patients with shock resulting from bleeding and without major intracranial or spinal cord trauma were randomized to resuscitation, starting immediately after admission, to either normal values of systolic blood pressure, urine output, base deficit, hemoglobin, and cardiac index (control group, 35 patients) or optimal values (cardiac index >4.5 L/min/m2, ratio of transcutaneous oxygen tension to fractional inspired oxygen >200, oxygen delivery index >600 mL/min/m2, and oxygen consumption index >170 mL/min/m2; optimal group, 40 patients). Initial cardiac output monitoring was done noninvasively by bioimpedance and, subsequently, invasively by thermodilution. Crystalloids, colloids, blood, inotropes, and vasopressors were used by predetermined algorithms. ResultsOptimal values were reached intentionally by 70% of the optimal patients and spontaneously by 40% of the control patients. There was no difference in rates of death (15% optimal vs. 11% control), organ failure, sepsis, or the length of intensive care unit or hospital stay between the two groups. Patients from both groups who achieved optimal values had better outcomes than patients who did not. The death rate was 0% among patients who achieved optimal values compared with 30% among patients who did not. Age younger than 40 years was the only independent predictive factor of the ability to reach optimal values. ConclusionsSeverely injured patients who can achieve optimal hemodynamic values are more likely to survive than those who cannot, regardless of the resuscitation technique. In this study, attempts at early optimization did not improve the outcome of the examined subgroup of severely injured patients.


Journal of Trauma-injury Infection and Critical Care | 1996

Radiographic cervical spine evaluation in the alert asymptomatic blunt trauma victim : much ado about nothing

George C. Velmahos; Dimitrios Theodorou; Raymond Tatevossian; Howard Belzberg; Cornwell Ee rd; T. V. Berne; Juan A. Asensio; Demetrios Demetriades

OBJECTIVE To evaluate the hypothesis that alert nonintoxicated trauma patients with negative clinical examinations are at no risk of cervical spine injury and do not need any radiographic investigation. DESIGN Prospective study. SETTING A university-affiliated teaching county hospital. PATIENTS Five hundred and forty-nine consecutive alert, oriented, and clinically nonintoxicated blunt trauma victims with no neck symptoms. RESULTS All patients had negative clinical neck examinations. After radiographic assessment, no cervical spine injuries were identified. Less than half the patients could be evaluated adequately with the three standard initial views (anteroposterior, lateral, and odontoid). All the rest needed more radiographs and/or computed tomographic scans. A total of 2,27 cervical spine radiographs, 78 computed tomographic scans and magnetic resonance imagings were performed. Seventeen patients stayed one day in the hospital for no other reason but radiographic clearance of an asymptomatic neck. The total cost for x-rays and extra hospital days was


Journal of The American College of Surgeons | 1998

Inability of an aggressive policy of thromboprophylaxis to prevent deep venous thrombosis (dvt) in critically injured patients: are current methods of dvt prophylaxis insufficient?

George C. Velmahos; John J. Nigro; Raymond Tatevossian; James Murray; Edward E. Cornwell; Howard Belzberg; Juan A. Asensio; Thomas V. Berne; Demetrios Demetriades

242,000. These patients stayed in the collar for an average of 3.3 hours (range, 0.5-72 hours). There was never an injury missed. CONCLUSIONS Clinical examination alone can reliably assess all blunt trauma patients who are alert, nonintoxicated, and report no neck symptoms. In the absence of any palpation or motion neck tenderness during examination, the patient may be released from cervical spine precautions without any radiographic investigations.


Critical Care Medicine | 2000

Transcutaneous oxygen and CO2 as early warning of tissue hypoxia and hemodynamic shock in critically ill emergency patients.

Raymond Tatevossian; Charles C. J. Wo; George C. Velmahos; Demetrios Demetriades; William C. Shoemaker

BACKGROUND Deep venous thrombosis (DVT) in severely injured patients is a life-threatening complication. Effective and safe thromboprophylaxis is highly desirable to prevent DVT. Low-dose heparin (LDH) and sequential compression device (SCDs) are the most frequently used methods. Inappropriate use of these methods because of the nature or site of critical injuries (eg, brain lesion, solid visceral or retroperitoneal hematoma, extremity fractures) may lead to failure of DVT prophylaxis. STUDY DESIGN A prospective study was performed to evaluate the efficacy of a policy of aggressive use of LDH and SCDs in patients who are at very high risk for DVT. From January 1996 to August 1997, 200 critically injured patients were followed by weekly Doppler examinations to detect DVT at the proximal lower extremities. Only 3 patients did not receive any thromboprophylaxis. SCDs were applied in 97.5% and LDH was administered to 46% of the patients; 45% had both. RESULTS DVT was found in 26 patients (13%). The majority (58%) developed DVT within the first 2 weeks, but new cases were found as late as 12 weeks after admission. The incidence of DVT was the same among patients who had SCDs only or a combination of LDH and SCDs. Mechanism of injury, type and number of operations, site of injury, Injury Severity Score, and the incidence of femoral lines were not different between patients with and without DVT. Differences were found in the severity of injury to the chest and the extremities and the need for high-level respiratory support. Patients with DVT had prolonged ICU and hospital stays (on average, 34 and 49 days, respectively) and a high mortality rate (31%). CONCLUSIONS The incidence of DVT remains high among severely injured patients despite aggressive thromboprophylaxis. A combination of LDH and an SCD showed no advantage over SCD alone in decreasing DVT rates. Risk factors in this group of patients who are already at very high risk are hard to detect; Doppler examinations are justified for surveillance in all critically injured patients. Current methods of thromboprophylaxis seem to offer limited efficacy, and the search for more effective methods should continue.


American Journal of Surgery | 1997

A selective approach to the management of Gunshot wounds to the back

George C. Velmahos; Demetrios Demetriades; Esteban Foianini; Raymond Tatevossian; Edward E. Cornwell; Juan A. Asensio; Howard Belzberg; Thomas V. Berne

Background Although cardiac and pulmonary function can be measured precisely, evaluation of tissue perfusion remains elusive because it usually is inferred from subjective symptoms and imprecise signs of shock. The latter are indirect criteria used to assess the overall circulatory status as well as tissue perfusion but are not direct quantitative measures of perfusion. However, noninvasive transcutaneous oxygen (PtcO2) and carbon dioxide (PtcCO2) tensions, which directly measure skin oxygenation and CO2 retention, may be used to objectively evaluate skin oxygenation and perfusion in emergency patients beginning with resuscitation immediately after hospital admission. Objective This study was a preliminary evaluation of tissue oxygenation and perfusion by objective PtcO2 and PtcCO2 patterns in severely injured surviving and nonsurviving patients; specifically, the aim was to describe time patterns that may be used as early warning signs of circulatory dysfunction and death. Design Prospective descriptive study of a consecutive series of severely injured emergency patients. Setting University-affiliated Level I trauma center and intensive care unit. Patients and Methods Forty-eight consecutive severely injured patients were prospectively monitored by PtcO2 and PtcCO2 sensors immediately after emergency admission. Results Compared with survivors, patients who died had significantly lower PtcO2 and higher PtcCO2 values beginning with the early stage of resuscitation. All patients who maintained PtcO2 >150 torr (19.99 kPa) throughout monitoring survived. Periods of PtcO2 <50 torr (6.66 kPa) for >60 mins or PtcCO2 >60 torr (8.00 kPa) for >30 mins were associated with 90% mortality and 100% morbidity. Conclusion PtcO2 and PtcCO2 monitoring continuously evaluate tissue perfusion and serve as early warning in critically injured patients during resuscitation immediately after hospital admission.


Journal of Trauma-injury Infection and Critical Care | 1998

Predicting the need for thoracoscopic evacuation of residual traumatic hemothorax: chest radiograph is insufficient.

George C. Velmahos; Demetrias Demetriades; Linda Chan; Raymond Tatevossian; Edward E. Cornwell; Nabil A. Yassa; James Murray; Juan A. Asensio; Thomas V. Berne

BACKGROUND Gunshot wounds to the back with retroperitoneal trajectories have been traditionally managed under the same guidelines as anterior gunshot wounds. Recent work has suggested that selective nonoperative management of anterior abdominal gunshot wounds is safe. The role of this policy in gunshot wounds to the back, where retroperitoneal organ injuries may be more difficult to detect clinically, has not been investigated. OBJECTIVE To examine if selective nonoperative management based on clinical assessment is a safe alternative to mandatory exploration for gunshot wounds to the back. DESIGN Prospective study. SETTING Large-volume level-1 university affiliated trauma center. PATIENTS AND METHODS Two hundred and three consecutive patients with gunshot wounds to the back were managed according to a protocol during a 12-month period. Patients with hemodynamic instability or peritonitis underwent urgent operation. The rest of the patients were observed with careful serial clinical examinations. RESULTS Eleven patients underwent an emergency room thoracotomy and were excluded. Four more patients were operated upon, despite the absence of abdominal findings, because of associated spinal cord injuries (2 patients), inability to observe due to need for repair of an associated peripheral vascular injury (1 patient), and participation in another protocol of aggressive evaluation of asymptomatic patients with suspected diaphragmatic injuries (1 patient). Of the remaining 188 patients, 58 (31%) underwent laparotomy (56 therapeutic, 2 negative) and 130 (69%) were initially observed owing to negative clinical examination. Following the development of increasing abdominal tenderness, 4 of these 130 (3%) underwent delayed explorations, which were all nontherapeutic. The sensitivity and specificity of initial clinical examination in detecting significant intraabdominal injuries were 100% and 95%, respectively. CONCLUSIONS Mandatory laparotomy is not necessary for gunshot wounds of the back. Clinical examination is a safe method of selecting patients for nonoperative management. An observation period of 24 hours is adequate for patients with no abdominal symptoms.


Injury-international Journal of The Care of The Injured | 2001

Penetrating trauma in patients older than 55 years: a case-control study

Bradley Roth; George C. Velmahos; Oder D; Raymond Tatevossian; Demetrios Demetriades; Howard Belzberg; Kathleen Alo

BACKGROUND The early removal of large residual posttraumatic hemothorax by videothoracoscopy is increasingly used to avoid the late sequelae of trapped lung and empyema. Plain chest radiography (CXR) is the tool most frequently used to select such cases for operation. Our recent experience has demonstrated that what appears to be a large retained hemothorax on CXR may turn out to be intrapulmonary or extrapleural conditions not amenable to thoracoscopic removal. Our objective was to evaluate the accuracy of CXR in detecting significant residual hemothorax and compare its clinical value to thoracic computed tomography (CT) when used to select patients for thoracoscopic evacuation. METHODS All patients requiring tube thoracostomy for traumatic hemothorax were prospectively evaluated during a 22-month period (n = 703). Patients who, on the second day after admission, demonstrated opacification on CXR involving more than the costophrenic angle were evaluated by thoracic computed tomography for the presence of undrained fluid. Second-day CXR (CXR2) results were compared with the CT findings. Incorrect interpretation was defined as a difference of more than 300 mL between the two readings. All CXR2 and CT results were reviewed in the same fashion by a radiologist blinded to the surgeons interpretations. Data on injury mechanism, hemodynamic status, laboratory values, interventions, and outcome were collected prospectively. RESULTS Fifty-eight patients had clinically significant opacifications on CXR2. The surgeons and radiologists CXR2 interpretations were incorrect in 48 and 47% of the cases, respectively. The CT interpretations by the two specialists were in agreement in 97% of the cases. Management that would have been instituted on the basis of CXR2 findings was changed in 18 cases (31%). Twelve patients (21%) required early thoracoscopic evacuation of undrained collections. There was good correlation between the CT estimation and the thoracoscopically retrieved amount of blood. CONCLUSION Although CXR is useful as a screening tool, it cannot be used to reliably select patients for surgical evacuation of retained traumatic hemothorax. Decision-making should be based on thoracic CT findings.


Journal of Bone and Joint Surgery, American Volume | 2013

Continuous Thoracocervical Epidural Analgesia for Management of Perioperative Pain in an Adolescent with Osteosarcoma

Jack M. Berger; Raymond Tatevossian; James H. Daniel; Sina Samie

BACKGROUND Multiple studies have compared young and elderly blunt trauma patients, and concluded that, because elderly patients have outcomes similar to young patients, aggressive resuscitation should be offered regardless of age. Similar data on penetrating trauma patients are limited. STUDY DESIGN In a retrospective review, 79 patients with penetrating injuries and age > or =55 were blindly matched for Injury Severity Score (ISS) and Abbreviated Injury Scores (AIS) with 79 penetrating trauma patients aged 15-35 years, who were admitted to the hospital over the same 4 year period (June 1994-June 1998). Mortality rates and length of stay in the intensive care unit (ICU) and the hospital were compared between the two groups. RESULTS The average ISS for all patients was 12 (range 1-75) and identical for both groups. Both groups had similar injuries and were evaluated by an equal number and type of diagnostic studies. The mean ISS was not different between severely injured older and younger patients who required ICU admission or died. Among 32 nonsurvivors (18 older and 14 younger), older patients were more likely than younger patients to present with normal vital signs, although the comparison did not reach statistical significance (50% vs. 13%, P=0.25). There was a clinically significant trend for longer ICU (15+/-30 vs. 3+/-2 days, P=0.096) and hospital stay (10+/-18 vs. 6+/-8 days, P=0.08) among older patients, but mortality rates were similar (23% in older vs. 18% in younger, P=NS). Furthermore, these outcome parameters showed no difference when both groups were classified according to severity of injury or physiologic response. CONCLUSIONS Following penetrating trauma, older patients arriving alive and admitted to the hospital are as likely to survive as younger patients who have injuries of similar severity, but at the expense of longer ICU and hospital stays.


Medical Imaging 2006: Physiology, Function, and Structure from Medical Images | 2006

Plexus structure imaging with thin slab MR neurography: rotating frames, fly-throughs, and composite projections

David T. Raphael; Diane McIntee; Jay S. Tsuruda; Patrick M. Colletti; Raymond Tatevossian; James Frazier

Osteosarcoma, an aggressive spindle-cell neoplasm, is the most common bone malignancy in children and young adults, with an incidence of 1 in 100,000 persons1. The presenting symptoms are pain and swelling of the affected extremity. The cause of pain is twofold: mass effect limiting motion and direct nerve involvement of the proximal neurovascular bundles. Osteosarcoma causes complex unrelenting pain, resulting in high opioid requirements. Because the treatment of osteosarcoma is neoadjuvant chemotherapy and resection, it is understandable that adequate pain control is an integral component of the multidisciplinary care required by these patients. There are multiple modalities to address upper-extremity cancer pain, including continuous systemic opioids, peripheral nerve blocks, and cervical epidural anesthesia, each with unique benefits and drawbacks. To the best of our knowledge, no study has been identified that addresses the early intervention (longer than seventy-two hours) of cervical epidural analgesia for preoperative pain control in this population, with continued use during and after surgery. We present a case in which we used cervical epidural anesthesia with 0.375% bupivacaine without opioids to provide effective perioperative pain control in a pediatric postpartum patient scheduled for a forequarter amputation because of osteosarcoma of the left humerus. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A fifteen-year-old girl (gravida 1, para 0 in the third trimester) presented to the emergency room with left shoulder and arm pain. A radiograph identified a mass in the left humerus. The patient was lost to follow-up and subsequently returned to the hospital late in her third trimester with progression of pain and an evident shoulder mass. She was diagnosed with osteosarcoma of the proximal part of the humerus with brachial plexus involvement, but there was no evidence of metastasis. During this hospitalization, the …


Chest | 1999

High-frequency percussive ventilation improves oxygenation in patients with ARDS.

George C. Velmahos; Linda S. Chan; Raymond Tatevossian; Edward E. Cornwell; William R. Dougherty; Joe Escudero; Demetrios Demetriades

We explored multiple image processing approaches by which to display the segmented adult brachial plexus in a three-dimensional manner. Magnetic resonance neurography (MRN) 1.5-Tesla scans with STIR sequences, which preferentially highlight nerves, were performed in adult volunteers to generate high-resolution raw images. Using multiple software programs, the raw MRN images were then manipulated so as to achieve segmentation of plexus neurovascular structures, which were incorporated into three different visualization schemes: rotating upper thoracic girdle skeletal frames, dynamic fly-throughs parallel to the clavicle, and thin slab volume-rendered composite projections.

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Demetrios Demetriades

University of Southern California

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Howard Belzberg

University of Southern California

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Thomas V. Berne

University of Southern California

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James Murray

University of Southern California

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Charles C. J. Wo

University of Southern California

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Linda S. Chan

University of Southern California

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William C. Shoemaker

University of Southern California

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