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Biomedical subjects

G Velmahos

Publications and source records attributed to G Velmahos.

At least 37 records · Page 2Linked to original sources
PubMed1998

Multicenter study of noninvasive monitoring systems as alternatives to invasive monitoring of acutely ill emergency patients.

BACKGROUND: Recent reports showed lack of effectiveness of pulmonary artery catheterization in critically ill medical patients and relatively late-stage surgical patients with organ failure. Since invasive monitoring requires critical care environments, the early hemodynamic patterns may have been missed. Ideally, early noninvasive hemodynamic monitoring systems, if reliable, could be used as the "front end" of invasive monitoring to supply more complete descriptions of circulatory pathophysiology. OBJECTIVES: To evaluate the accuracy and reliability of noninvasive hemodynamic monitoring consisting of a new bioimpedance method for estimating cardiac output combined with arterial BP, pulse oximetry, and transcutaneous PO2 and PCO2; we compared this system of noninvasive monitoring with simultaneous invasive measurements to evaluate circulatory deficiencies in acutely ill patients shortly after hospital admission where invasive monitoring was not readily available. We also preliminarily explored early differences in temporal hemodynamic patterns of survivors and nonsurvivors. DESIGN AND SETTING: Prospective comparison of simultaneous invasive and noninvasive measurements of circulatory function with retrospective analysis of data in university-run county hospitals, university hospitals and affiliated teaching hospitals, and a community private hospital. PATIENTS: We studied 680 patients, including 139 severely injured or hemorrhaging patients in the emergency department (ED), 129 medical (nontrauma) patients on admission to the ED, 274 high-risk surgical patients intraoperatively, and 138 patients recently admitted to the ICU. RESULTS: A new noninvasive impedance device provided cardiac output estimations under conditions in which invasive thermodilution measurements were not usually applied. There were 2,192 simultaneous bioimpedance and thermodilution cardiac index measurements; the correlation coefficient, r = 0.85, r2 = 0.73, p < 0.001. The precision and bias was -0.124+/-0.75 L/min/m2. Both invasive and noninvasive monitoring systems provide similar information and identified episodes of hypotension, low cardiac index, arterial hemoglobin desaturation, low transcutaneous O2, high transcutaneous CO2, and low oxygen consumption before and during initial resuscitation. The limitations of noninvasive systems were described. CONCLUSIONS: Noninvasive monitoring systems gave continuous displays of physiologic data that provided information allowing early recognition of low flow and poor tissue perfusion that were more pronounced in the nonsurvivors. Noninvasive systems may be acceptable alternatives where invasive monitoring is not available.

Adult↗
PubMed1998

The prevalence and effect of alcohol and drug abuse on cohort-matched critically injured patients.

A prospective study was undertaken at a Level I trauma center to evaluate the prevalence of substance use among victims of major trauma, along with the impact on clinical outcome. Five hundred sixteen patients had urine toxicology and blood alcohol screens performed and correlated with pattern and severity of injury, hospital course, and outcome. Three hundred seventy-one patients (71%) screened positive for alcohol or drugs, or both. Fifty-two per cent had positive alcohol screens, and 42 per cent had positive drug screens (cocaine and opiates represented 91% of positive drug screens). Univariate analysis revealed patterns of alcohol/drug use varied among subgroups according to demographics (less use among patients older than 55 years, females and Asians; more drug use in blacks; more alcohol use in Hispanics), mechanism of injury (non-use in blunt trauma patients and use of both in penetrating trauma patients) and body region injured (non-use in head-injured patients). Septic complications and mortality were more correlative with severity of injury, but not with use or non-use of alcohol or drugs. We conclude that alcohol and drug use remains a major comorbid factor in major trauma, and that injury prevention efforts should include a strong focus on counseling regarding these lifestyle choices.

Adolescent↗
PubMed1997

Selective nonoperative management of gunshot wounds of the anterior abdomen.

OBJECTIVE: To investigate the role of selective nonoperative management of gunshot wounds to the abdomen. DESIGN: A prospective, protocol-guided study including all gunshot wounds of the anterior abdomen. PATIENTS AND METHODS: The patients were assessed and managed according to a written protocol. Patients with hemodynamic instability or peritonitis or associated spinal cord or head injury or requiring a general anesthetic for an extra-abdominal injury were managed by laparotomy. The test of the patients were selected for initial nonoperative management with serial physical examinations. RESULTS: During a 16-month period, 309 patients with gunshot wounds of the anterior abdomen were treated. Eighteen patients in extremis (5.8%) underwent an emergency department-performed thoracotomy. Another 185 patients (59.9%) met the criteria for operation and underwent a laparotomy. The incidence of nontherapeutic operations was 2.2%, and that of negative operations was 8.6%. One hundred six patients (34.3%) were selected for observation. Fourteen of the initially observed patients underwent a late operation, but it was therapeutic in only 5. Overall, 92 patients (29.8%) were successfully managed nonoperatively. The overall sensitivity of the initial physical examination was 97.1%. The estimated bullet trajectory was not reliable in identifying the need for operation because of 224 patients with likely peritoneal penetration only 169 (75.4%) had significant injuries requiring surgical repair. CONCLUSION: In the appropriate environment, many civilian abdominal gunshot wounds can be managed non-operatively.

Abdominal Injuries↗
PubMed1997

Evaluation of penetrating injuries of the neck: prospective study of 223 patients.

The objective of this study was to assess the role of clinical examination, angiography, color flow Doppler imaging, and other diagnostic tests in identifying injuries to the vascular or aerodigestive structures in patients with penetrating injuries to the neck. A prospective study was made of patients with penetrating neck injuries. All patients had a careful physical examination according to a written protocol. Stable patients underwent routine four-vessel angiography and color flow Doppler imaging. Esophagography and endoscopy were performed for proximity injuries. The sensitivity, specificity, and predictive values of physical examination, color flow Doppler studies, and other diagnostic tests were assessed during the evaluation of vascular and aerodigestive tract structures in the neck. Altogether 223 patients were entered in the study. After physical examination 176 patients underwent angiography and 99 of them underwent color flow Doppler imaging. Angiographic abnormalities were seen in 34 patients for an incidence of 19.3%, but only 14 (8.0%) required treatment. Color flow Doppler imaging was performed on 99 patients with a sensitivity of 91.7%, specificity 100%, positive predictive value (PPV) 100%, and negative predictive value (NPV) 99%. These values were all 100% when only injuries requiring treatment were considered. None of the 160 patients without clinical signs of vascular injury had serious vascular trauma requiring treatment (NPV 100%), although angiography in 127 showed 11 vascular lesions not requiring treatment. "Hard" signs on clinical examination (large expanding hematomas, severe active bleeding, shock not responding to fluids, diminished radial pulse, bruit) reliably predicted major vascular trauma requiring treatment. Among 34 of the 223 total patients (15.2%) admitted with "soft" signs, 8 had angiographically detected injuries, but only one required treatment. An esophagogram was performed on 98 patients because of proximity injuries (49 patients) or suspicious clinical signs (49 patients), and two of them showed esophageal perforations. None of the 167 patients without clinical signs of esophageal trauma had an esophageal injury requiring treatment. It was concluded that physical examination is reliable for identifying those patients with penetrating injuries of the neck who require vascular or esophageal diagnostic studies. Color flow Doppler imaging is a dependable alternative to angiography. An algorithm for the initial assessment of neck injuries is suggested.

Algorithms↗
PubMed1997

A unified approach to the surgical exposure of pancreatic and duodenal injuries.

One of the greatest challenges to any surgeon is the intraoperative detection and surgical management of duodenal and pancreatic injuries. A uniform approach to the surgical exposure of all suspected pancreatic and duodenal injuries will decrease their morbidity and mortality by identifying all injuries. Proper intraoperative assessment and grading will help with procedure selection from the broad surgical armamentarium available to manage these injuries.

Duodenum↗
PubMed1997

Penetrating esophageal injuries: time interval of safety for preoperative evaluation--how long is safe?

OBJECTIVES: This study was performed to assess the experience with penetrating esophageal injuries of an urban Level I trauma center and to attempt to correlate the time to establish a diagnosis with outcome including death, surgical intensive care unit length of stay, and esophageal-related complications. METHODS: Retrospective study over a 72-month period at a single institution comparing age, admission blood pressure, Revised Trauma Score (RTS), Injury Severity Score (ISS), mechanism and anatomic location of injury, and time interval from admission to the operating room (OR) between nonsurvivors and survivors. Patients who survived to reach the operating room were divided into two groups: those who went immediately to the operating room (no preoperative evaluation) and those who underwent diagnostic studies to identify their injuries (preoperative evaluation). Data analysis was done of the same parameters plus average number of associated injuries, complications, and intensive care unit length of stay. Statistical methods used univariate analysis (Fisher's exact test and Student's t test). RESULTS: Forty-three patients were identified with penetrating esophageal injuries and had the following characteristics: 36 males (84%) and 7 females (16%); mean RTS, 9.39; mean ISS, 28.1; mean time interval to OR, 9.8 hours. Associated injuries occurred with 42 patients (98%). The overall complication rate was 14 of 32 (44%), and the overall mortality was 11 of 43 (26%). Corrected mortality was 22%. Differences were noted between nonsurvivors and survivors in the following parameters: admission blood pressure < 90, 11 of 11 versus 3 of 29 (p < 0.001); RTS, 2.364 versus 11.406 (p < 0.001); ISS, 45 versus 21 (p < 0.001); time interval from admission to OR, 18.3 minutes versus 9.8 hours (p < 0.05). Thirty-six patients survived to reach the operating room, 18 in the no preoperative evaluation group and 17 in the preoperative evaluation group. No statistically significant differences were noted between these two groups in the following parameters: age, RTS, ISS, admission blood pressure, anatomic location of injury, number of associated injuries, or intensive care unit length of stay. Average length of time to the operating room was 16.7 hours in the preoperative evaluation group and 1.4 hours in the no preoperative evaluation group (p < 0.001). Twelve complications (all esophageal-related) occurred among seven patients in the preoperative evaluation group, and seven complications (five esophageal-related) occurred among seven patients in the no preoperative evaluation group. Because of the small sample size, this failed to reach a statistical difference (p < 0.05). CONCLUSIONS: Esophageal injuries carry a high morbidity and mortality. Although no definite conclusion can be drawn because of the small sample size, there does appear to be an increased morbidity associated with the diagnostic workup and its inherent delay in operative repair of these injuries. For centers practicing selective management of penetrating neck injuries and transmediastinal gunshot wounds, the rapid diagnosis and definitive repair of esophageal injury should be made a high priority.

Adult↗
PubMed1997

Penetrating left thoracoabdominal trauma: the incidence and clinical presentation of diaphragm injuries.

OBJECTIVE: The objective of this study was to (1) determine the incidence of diaphragmatic injuries in penetrating left thoracoabdominal trauma and (2) evaluate the role of laparoscopy in detecting clinically occult diaphragmatic injuries. PATIENTS AND METHODS: One hundred nineteen consecutive patients with penetrating injuries to the left thoracoabdominal region presenting to Los Angeles County-University of Southern California Medical Center were prospectively evaluated during an 8-month period. Either celiotomy (with hemodynamic instability or peritonitis) or laparoscopy was performed. Results of the clinical examination and roentgenographic findings were recorded preoperatively. RESULTS: One hundred seven patients were fully evaluated. Fifty patients required emergent celiotomy. Fifty-seven patients underwent laparoscopy. The overall incidence of diaphragmatic injuries was 42% (59% for gunshot wounds, 32% for stab wounds). Among the 45 patients with diaphragmatic injuries, 31% had no abdominal tenderness, 40% had a normal chest roentgenogram, and 49% had an associated hemopneumothorax. Fifteen of the patients undergoing laparoscopy (26%) had occult diaphragm injuries. CONCLUSION: (1) The incidence of diaphragmatic injuries in association with penetrating left thoracoabdominal trauma is high. (2) The clinical and roentgenographic findings are unreliable at detecting occult diaphragmatic injuries. (3) Laparoscopy is a vital tool for detecting occult diaphragmatic injuries among patients who have no other indications for formal celiotomy.

Abdominal Injuries↗
PubMed1997

Laparoscopic inguinal hernia repair by an intraperitoneal onlay mesh technique using expanded PTFE: a prospective study.

This prospective trial was initiated to assess laparoscopic inguinal hernia repairs by an intraabdominal intraperitoneal onlay mesh (IPOM) technique. An IPOM method utilizing 10 x 7.5-cm expanded polytef (PTFE) patches was used to repair 52 inguinal hernias in 50 patients. There were two patients with bilateral defects. Fourteen were direct and 38 were indirect hernias. There was one patient with bladder perforation, one with strangulation of the small bowel that entered the sac of a recurrent defect, and five patients with other minor complications. There were two recurrences. The follow-up period ranged from 7 to 31 months. The operating time ranged from 35 to 180 min and was 35-60 min in 40 patients. The postoperative pain was minimal in 40 patients. Our conclusions are as follows: This IPOM method was less time consuming in theater time than other laparoscopic methods. There was minimal postoperative pain in the majority of cases. The hospital stay was shorter in comparison with the standardized stay for conventional methods. The case with recurrence and strangulation raises some questions as to the safety of this method. Hospital costs of conventional herniorrhaphies were lower (63%) than those of this laparoscopic method.

Adolescent↗
PubMed1996

Transmediastinal gunshot wounds. A reconsideration of the role of aortography.

OBJECTIVE: To evaluate the contribution of aortography in the management of stable patients with transmediastinal gunshot wounds. DESIGN: Retrospective review of clinical records. SETTING: Level I urban trauma center. PATIENTS: Forty-three patients with aortic or esophageal gunshot injuries. INTERVENTIONS: Patients who were stable after initial resuscitation underwent aortography followed by esophagography. MAIN OUTCOME MEASURES: Hemodynamic status on admission, time devoted to diagnostic workup, surgical (or autopsy) findings, morbidity, and mortality. RESULTS: There were 24 esophageal injuries and 20 aortic injuries. Patients with aortic injuries were less often stable for aortography (10% vs 42%; P = .02), and fewer of them survived (15% vs 58%; P = .01). In no patient was the aortic injury initially detected by aortography. Stable patients with esophageal injuries experienced an average 11-hour interval between injury and surgery (nearly 3 hours attributable to aortography). CONCLUSION: Esophageal evaluation should precede aortography in the workup of stable patients with transmediastinal gunshot wounds.

Adolescent↗
PubMed1996

Complex problems in penetrating neck trauma.

This article discusses the problems and controversies in the assessment of penetrating injuries of the neck. The role of physical examination and color-flow Doppler imaging in the initial assessment is highlighted. Complex injuries of major vessels, the aerodigestive tract, and the parotid are discussed and therapeutic options are presented.

Angiography↗
PubMed1996

Transcervical gunshot injuries: mandatory operation is not necessary.

BACKGROUND: It has been suggested that all transcervical gunshot wounds should be explored surgically because of the high incidence of injuries to vital structures. The present prospective study investigated the clinical presentation, the role of various diagnostic investigations, and the need for surgery in patients with transcervical gunshot injuries. METHODS: Ninety-seven patients sustained gunshot injuries to the neck and 33 of them (34%) were transcervical. All victims were assessed clinically according to a written protocol and subsequently were evaluated angiographically, and, in the appropriate case, by means of endoscopy and esophagography. RESULTS: Overall, 24 (73%) of the 33 patients with transcervical gunshot wounds had injuries to cervical structures. Vascular injuries were found in 48%, spinal cord injuries in 24%, and aerodigestive tract injuries in 6% of patients with transcervical injuries. In the 64 patients without midline crossing, the incidence of cervical structure injuries was 31%. Despite the high incidence of injuries to cervical structures in transcervical wounds, only 21% of the patients had a therapeutic operation. The overall mortality was 3%. There were no in-hospital deaths or local complications in the nonoperatively managed group. CONCLUSIONS: The results of the present study do not support the current recommendations of mandatory operation for all transcervical gunshot wounds. A careful clinical examination combined with the appropriate diagnostic investigations should determine the treatment modality. About 80% of these patients can safely be managed nonoperatively.

Adolescent↗
PubMed1996

Mortality and prognostic factors in penetrating injuries of the aorta.

PURPOSE: This study was designed to investigate the epidemiology and prognostic factors determining survival in penetrating injuries of the aorta. PATIENTS AND METHODS: This was a retrospective analysis of all patients with penetrating aortic injuries, admitted to a large, level I trauma center. The following factors were analyzed for their role in determining survival: mechanism of injury, anatomical site of the aortic injury, initial blood pressure on admission, need for emergency room thoracotomy, and the introduction of a dedicated trauma program with an attending surgeon in-house. RESULTS: There were 93 patients with penetrating aortic injuries over a 5-year period. The abdominal aorta was injured in 67 patients (72%) and the thoracic aorta in 26 (28%). Most of the victims (82.5%) were admitted in shock and 41% had an unrecordable blood pressure on admission. Victims with injury to the thoracic aorta were more likely to have an unrecordable blood pressure on admission than patients with abdominal aortic injuries (73% vs 28.4%), and more likely to require an emergency room thoracotomy (76.9% vs 20.9%). Thirty-four patients (36.6%) required an emergency room thoracotomy and there were no survivors. The overall mortality was 80.6% (87.5% for gunshot injuries, 64.7 % for knife injuries). Patients with abdominal aortic injuries were three times more likely to survive than those with thoracic aortic injuries (23.9% vs 7.7%). The introduction of a dedicated trauma program, which resulted in significant reduction of mortality in other types of severe trauma, had no effect on the outcome in aortic injuries. CONCLUSIONS: Penetrating aortic injuries still have a very high mortality rate with no improvement in survival despite improved trauma services. Injury to the thoracic aorta, gunshot wounds, unrecordable blood pressure on admission, and the need for emergency room thoracotomy, are important predictors of high mortality.

Adolescent↗
PubMed1996

Use of large databases for resolving critical care problems.

Large databases allow for rapid access to large volumes of data. To convert raw data to information, large numbers of data points must be correlated into a descriptive pattern that can be interpreted by the user. Databases must be constructed so as to allow reliable extraction of the raw data into a format that supports analysis of events in a meaningful, objective, and reproducible manner. Databases must be responsive to a variety of users. They must not demand unrealistic amounts of effort on those responsible for data entry. Standard protocols in various stages of development will make databases easier to use and more reliable. Database management tools such as the Internet and the National Library of Medicine will become more integrated into the practice of critical care medicine at all levels, including administration, clinical care, and research. This article provides an overview of the capabilities and difficulties associated with large databases. The major areas of use of large databases in the hospital setting are administration, bibliographic, patient care, research, and education. Each of these areas has different requirements and is supported by different types of databases. The advantages and disadvantages of linear, relational, and object-oriented databases are discussed. Issues relating to methods of data entry and the accuracy and reliability of data are discussed. The challenges involving integration of various sources of data and the interfacing of devices are reviewed.

Critical Care↗
PubMed1995

Penetrating injuries of the neck in patients in stable condition. Physical examination, angiography, or color flow Doppler imaging.

BACKGROUND: The initial assessment of penetrating injuries of the neck is controversial, with angiography remaining the gold standard for identifying vascular injuries. Recent reports suggest that physical examination might be an accurate way to evaluate these injuries. Color flow Doppler imaging has been used with promising results to assess extremity injuries, but the role of color flow Doppler imaging in neck injuries has not been studied. OBJECTIVE: To evaluate and compare the roles of physical examination, color flow Doppler imaging, and angiography in the identification and management of penetrating neck injuries. STUDY DESIGN: A prospective study of patients in stable condition with penetrating injuries of the neck. All study patients were examined according to a written clinical protocol and subsequently underwent angiography and color flow Doppler imaging. The sensitivity and specificity of physical examination and color flow Doppler imaging were compared with those of angiography. RESULTS: Eighty-two patients fulfilled the criteria for inclusion in the study. Angiography demonstrated vascular lesions in 11 patients (13.4%), but only two (2.4%) of them required treatment. Serious injuries were detected or suspected during physical examination, but six lesions not requiring treatment were missed. When injuries not requiring treatment were excluded, the sensitivity was 100% and the specificity was 91%. With color flow Doppler imaging, 10 of the 11 injuries were identified, for a sensitivity of 91% and a specificity of 98.6%. The sensitivity and specificity were 100% for clinically important lesions. CONCLUSION: The combination of a careful physical examination and color flow Doppler imaging provides a reliable way to assess penetrating neck trauma and may be a safe alternative to routine contrast angiography.

Adolescent↗
PubMed1994

Penetrating injuries of the subclavian vessels.

A study was made of 76 patients with subclavian vessel injury. The mechanism of trauma was stabbing in 40 patients (53 per cent) and gunshot in 36 (47 per cent). There were marked differences between the two groups in clinical presentation, operative management and outcome. The group with gunshot injury was characterized by a more immediate threat to life, and a greater need for a median sternotomy and use of interposition grafts. The mortality rate in patients with gunshot wounds was more than twice that in the group with stab injury.

Adult↗
PubMed1994

Gunshot wounds of the spine: should retained bullets be removed to prevent infection?

We have investigated the role of retained bullets and other possible risk factors in the development of local septic complications after gunshot wounds (GSW) of the spine. Of 153 patients with GSW of the spine followed up for a mean of 28 months, the overall incidence of bullet wound related septic complications was 9.8%. In 81 patients the bullet was retained and the incidence of local septic complications was 7.4%. In 72 patients the bullet left the body (70) or was removed on admission (2), and the sepsis rate was 12.5% (P > 0.05). In 24 patients there was an associated colonic injury and the incidence of sepsis was 8.4% compared with 5% in the group of patients with intra-abdominal injuries but no colonic trauma (P > 0.05). The incidence of septic complications in lumbar spine injuries was significantly higher than in thoracic and cervical spine injuries (P > 0.05). We believe that in GSW of the spine, retained bullets do not increase the likelihood of septic complications.

Adolescent↗