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Biomedical subjects

A O Udekwu

Publications and source records attributed to A O Udekwu.

At least 19 recordsLinked to original sources
PubMed1999

Trauma center maturation: quantification of process and outcome.

BACKGROUND AND OBJECTIVE: The regional trauma system with the trauma center as its center is a model for health care networks. However, trauma center maturation has not been defined in the literature. The authors' hypothesis was that maturation of the trauma center would affect quantitatively both process and patient outcome. MATERIALS AND METHODS: A total of 15,303 trauma patients were admitted from 1987 to 1995. Annual admissions increased from 813 to 2669. Resources were generated as patient volume increased. Time to the operating room, length of stay, and complications were determined. TRISS methodology was used to calculate z scores and w values to compare actual with predicted mortality rates. RESULTS: Time to the operating room for laparotomy decreased from 62+/-73 to 35+/-47 minutes, from 32+/-32 to 20+/-17 minutes in hypotensive patients, and for craniotomy decreased from 88+/-54 to 67+/-49 minutes. The incidence of infectious, airway, neurologic, orthopedic, respiratory, gastrointestinal, and procedure-related complications declined significantly. Z scores and w values increased for penetrating and blunt injuries. Deaths for patients with ISS >15 declined significantly. Hospital length of stay decreased for all ranges of injury severity. CONCLUSIONS: As the trauma center matured, the process of delivering patient care became more efficient. The result was improved survival, fewer complications, and a shorter length of stay.

Efficiency, Organizational↗
PubMed1998

Utility of clinical parameters of tissue oxygenation in a quantitative model of irreversible hemorrhagic shock.

The aim of this study was to assess the value of parameters of tissue oxygenation in monitoring the progression to irreversibility in a quantitative model of hemorrhagic shock. Rats were bled to a mean arterial pressure of 40 mmHg and were maintained at this level by further blood withdrawal until the compensation endpoint; this point was defined as the time at which the rat was no longer able to maintain its blood pressure at this level and shed blood was required for transfusion. The shock period was maintained until 0%, 20%, 40%, or 50% of the maximum shed blood volume (MBV) had been returned (n = 10 in each group, total n = 40). The animals were then resuscitated with remaining shed blood plus twice MBV as lactated Ringer's solution to MAP > 80 mmHg. Blood gas and serum lactate samples were measured at baseline, compensation endpoint, and at the time of resuscitation, and 24 h survival was recorded. Increasing the severity of shock progressively worsened the acidosis, with increased base deficit and lacticacidemia, and deterioration in central venous oxygen saturation (CvO2). Tissue oxygenation parameters, particularly CvO2, predicted subsequent mortality. Lactate levels only predicted irreversibility in late, severe shock. This quantitative model of hemorrhagic shock showed that tissue oxygenation parameters can be used to monitor the progression from the decompensated phase of hemorrhagic shock to irreversibility. Furthermore, this experimental study suggests that venous indices may be a valuable tool in reflecting the severity of hemorrhagic insult in a setting when arterial blood samples may not be easily available.

Animals↗
PubMed1997

Management of blunt splenic trauma: significant differences between adults and children.

BACKGROUND: Although highly successful in children, nonoperative management of blunt splenic injury in adults is less defined. The purpose of this study was to determine whether mechanism of injury, grade of splenic injury, associated injuries, and pattern of injury differ between adults and children (younger than 15 years of age). METHODS: Four hundred eleven patients (293 adults and 118 pediatric patients) with blunt splenic injury were admitted to an affiliated adult/pediatric trauma program from 1989 to 1994. Computed tomography (CT) scans were interpreted in a blinded fashion. Mechanism of injury was significantly different for adults versus children (p < 0.05): motor vehicle crash (66.9% versus 23.7%), motorcycle (8.8% versus 0.8%), sports (2.4% versus 16.9%), falls (8.8% versus 25.4%), pedestrian/automobile (4.4% versus 11.0%), bicycle (1.4% versus 9.3%), and other (7.3% versus 12.7%). RESULTS: Higher injury severity scores, lower Glasgow Coma Scales, and higher mortality indicated that the adults were more severely injured than the children. Fifty-nine percent of the adults and 7% of the children required immediate laparotomy for splenic injury. Both CT grade and quantity of blood on CT predicted the need for exploration in adults but not in children. An injury severity score above 15 and high-energy mechanisms correlated with the need for operative intervention. CONCLUSIONS: Rather than children simply being physically different, they are injured differently than adults, hence the high rate of nonoperative management.

Accidents, Traffic↗
PubMed1997

Effects of hemodilution on long-term survival in an uncontrolled hemorrhagic shock model in rats.

Prehospital guidelines for the treatment of penetrating trauma recommend rapid volume resuscitation to normal blood pressure. There is evidence, however, that fluid resuscitation to normal blood pressure in the setting of uncontrolled hemorrhagic shock (UHS) causes increased bleeding, hemodilution, and mortality. To test this hypothesis, we evaluated the effects of blood pressure and hemodilution on survival in a rat model of UHS. UHS was produced in rats by preliminary bleed of 3 mL/100 g followed by a 75% tail amputation. Experimental design consisted of three phases: a prehospital phase, with uncontrolled bleeding and resuscitation to either 40 or 80 mm Hg with lactated Ringer's solution (LR) or lactated Ringer's solution and whole blood (WB); followed by a hospital phase, with control of the bleeding and continued resuscitation to mean arterial pressure (MAP) > 80 mm Hg and hematocrit near 30%; followed by a 3-day observation phase. There were four treatment groups, n = 8 in each group: group I, MAP = 80 mm Hg with LR only; group II, MAP = 80 mm Hg with WB and LR; group III, MAP = 40 mm Hg with LR only; and group IV, MAP = 40 mm Hg with WB and LR. All group I rats died within 2.5 hours. There were no significant differences in survival among groups II, III, and IV. Base deficit, arterial pH, and lactate levels were significantly worse in the rats resuscitated to a MAP of 80 mm Hg with LR (group I). The effects of blood pressure alone, hemodilution alone, and their interaction were significantly related to base deficit and arterial pH. Hemodilution, but not blood pressure as an end point in resuscitation, was significantly related to lactate levels. The high mortality in this model of uncontrolled hemorrhage was attributable to the effects of blood pressure, hemodilution, and the interaction between the two variables, rather than simply continued blood loss from increased hydrostatic pressure.

Animals↗
PubMed1995

Hemorrhagic shock.

A great deal has been learned about the pathophysiologic condition of hemorrhagic shock. The response of the hormonal and inflammatory mediator systems in patients in hemorrhagic shock appears to represent a distinct set of responses different from those of other forms of shock. The classic neuroendocrine response to hemorrhage attempts to maintain perfusion to the heart and brain, often at the expense of other organ systems. This intense vasoconstriction occurs via central mechanisms. The response of the peripheral microcirculation is driven by local tissue hypoperfusion that results in vasodilation in the ischemic tissue bed. Activation of the systemic inflammatory response by hemorrhage and tissue injury is an important component of the pathophysiologic condition of hemorrhagic shock. Activators of this systemic inflammatory response include ischemia/reperfusion injury and neutrophil activation. Capillary "no-flow" with prolonged ischemia and "no-reflow" with reperfusion may initiate neutrophil activation in patients in hemorrhagic shock. The mechanisms that lead to decompensated and irreversible hemorrhagic shock include (1) "arteriolar hyposensitivity" as manifested by progressive arteriolar vasodilation and decreased responsiveness of the microcirculation to alpha-agonists, and (2) cellular injury and activation of both proinflammatory and counterinflammatory mechanisms. These changes represent a failure of the microcirculation. Redistribution of cardiac output and persistent gut ischemia after adequate resuscitation may also contribute to the development of irreversible hemorrhagic shock. Treatment of hemorrhagic shock includes rapid operative resuscitation to limit activation of the mediator systems and abort the microcirculatory changes that result from hemorrhagic shock. Volume resuscitation and control of hemorrhage, should occur simultaneously. The end point in volume resuscitation of hemorrhagic shock must be maintenance of organ system and cellular function. Whether we use adequate urine output, correction of lactic acidemia, optimization of oxygen delivery, or oxygen consumption as our specific goal, the general objective is to provide adequate crystalloid solution and packed red blood cells to achieve and maintain normal organ and cellular perfusion and function.

Adrenal Glands↗
PubMed1995

Evolution of management of major hepatic trauma: identification of patterns of injury.

Nonoperative management of hemodynamically stable patients following blunt hepatic trauma identified by computed tomography (CT) has been reported in up to 20% of patients presenting with hepatic injury, predominantly low grade. We reviewed 128 consecutive adult patients sustaining blunt hepatic trauma with the hypothesis that severe hepatic injuries (grades III to V) could be safely managed nonoperatively and to determine anatomic pattern and severity of hepatic injuries. Sixty-two of the 128 patients (47%) went directly for laparotomy, based on physical findings or positive peritoneal lavage. Sixty-six patients were hemodynamically stable and underwent abdominal CT scanning; 70% (46 of 66) were successfully managed nonoperatively. Fifty-one percent of grade III and IV injuries were treated nonoperatively. However, the majority of patients with grade V injuries were unstable, and 92% required laparotomy. Twenty-six of 46 patients treated nonoperatively (56%) had injury to the posterior segment of the right lobe of the liver or a "split liver." In retrospect, only 33% of patients with hepatic injury required laparotomy for therapy of the liver injury. Hemodynamic stability and anatomic pattern of injury on presentation were important factors in successful nonoperative management of hepatic injury.

Adolescent↗
PubMed1993

Avulsion of the internal mammary artery caused by blunt trauma.

Injury to the subclavian artery or its branches is uncommon after blunt trauma. We report a case of blunt thoracic trauma resulting in avulsion of the right internal mammary artery from its origin on the subclavian artery. This presented as an atypical mediastinal hematoma in a patient with multiple injuries.

Accidents, Traffic↗
PubMed1993

Nitric oxide production is inhibited in trauma patients.

Elevated levels of nitrates/nitrites, the stable endproducts of nitric oxide (NO), were recently observed in septic patients. In this setting, NO maintains blood flow by vasodilation and inhibition of platelet aggregation. Trauma patients were found to have low plasma levels of nitrates/nitrites, even when they developed sepsis. The current study substantiated that trauma patients have suppressed production of NO; reductions in plasma nitrate/nitrite levels correlated with low urinary excretion of these endproducts. Nitric oxide production was upregulated in trauma patients with clinical infection compared with trauma patients without infection, but was still significantly suppressed compared with nitric oxide production in normal controls. The inability of trauma patients to produce NO may be an important component of the susceptibility of these patients to infection.

Adolescent↗
PubMed1991

Nitrogen oxide levels in patients after trauma and during sepsis.

The mediators responsible for maintenance of the hyperdynamic state and the low systemic vascular resistance (SVR) observed in sepsis have not been elucidated. Nitric oxide (.N = O) is a mediator with numerous functions, including regulation of vascular tone and a role in macrophage-mediated cytostasis and microbiostasis. Thirty-nine critically ill trauma and septic patients were studied to determine the relationship between .N = O production and the hyperdynamic state. high plasma levels of NO2-/NO3- (the stable end products of .N = O) were observed in septic patients (p less than 0.02). Low SVR and high endotoxin levels were associated with high NO2-/NO3- values (p = 0.029, p = 0.002). Changes in .N = O levels may mediate the vasodilation seen in sepsis. Low NO2-/NO3- levels were observed in trauma patients (p less than 0.001) and remained low even in the presence of sepsis (p = 0.001).

Adult↗
PubMed1991

Argon beam coagulation is superior to conventional techniques in repair of experimental splenic injury.

Present management of splenic trauma focuses on splenic preservation. However, conventional operative techniques for splenic salvage are time consuming and frequently ineffective. The purpose of this study was to assess the efficacy of the argon beam coagulator (ABC) in the management of experimental splenic injury. Ten adult miniature pigs were randomized to treatment with either conventional surgical techniques (topical Surgicel, electrocautery, suture-ligation, digital pressure) or splenic repair with the ABC. Three standard splenic injuries were made in each pig: capsular avulsion, splenic laceration, and hemisplenectomy. The ABC was more effective in treating all three types of splenic injury. The time required to achieve hemostasis and total operative time were significantly less in the group treated with the ABC for all three types of splenic injuries (p less than 0.05, Student's t-test, two sided). Operative blood loss was significantly less in the group treated with ABC for avulsion and hemisplenectomy (p less than 0.05, Student's t-test, two sided). Recurrent bleeding was significantly higher in the group treated with conventional techniques (p less than 0.001, Fisher's exact test, two-sided). We conclude that the argon beam coagulator is more effective than conventional techniques in treating experimental splenic injuries. The ABC provides more rapid and reliable hemostasis. Clinical trials using the ABC for splenic injury are warranted.

Animals↗
PubMed1991

Bacterial translocation in trauma patients.

Sepsis and multiple system organ failure (MSOF) are major causes of morbidity and mortality in trauma patients. Bacterial translocation induced by hypotension, endotoxemia, or burns is a reproducible phenomenon in the laboratory. The incidence of bacterial translocation to mesenteric lymph nodes (MLNs) in 29 critically ill patients was evaluated to determine its relationship to subsequent sepsis and MSOF. Bacterial translocation was documented in 3 of 4 patients who underwent laparotomy for gastrointestinal (GI) disease. No trauma patient (25 patients), even at second exploration 3-5 days after injury, had a positive MLN culture. Five patients died; 4 trauma patients, one with GI disease. Forty percent of the trauma patients had major complications, predominantly pulmonary infections with gram-negative bacteria. However, infectious complications and outcome were not related to MLN culture results. The classical progression of bacteria from the gut to the bloodstream via the MLNs may require time and gut mucosal injury. The data suggest that bacterial translocation to the MLNs is not a common occurrence in acutely injured trauma patients.

Bacterial Physiological Phenomena↗
PubMed1991

Computed tomography in the evaluation of blunt abdominal trauma.

The role of computed tomography (CT) in the evaluation of victims of blunt abdominal trauma remains controversial. This study was done to assess the reliability of CT in the evaluation of blunt abdominal trauma at our institution, to determine if the incidence of nontherapeutic laparotomy has decreased with the use of CT scan and to review the time necessary to complete the scans. Of the 325 patients studied, 37 per cent were found to have abdominal injury on CT scan. Thirty patients required laparotomy; ten of these were nontherapeutic. Excluding transport time, abdominal CT scan required 55 +/- 20 minutes to complete. Abdominal CT was accurate when read by attending physicians (97.5 per cent). Major shortcomings included the commitment of time and personnel, transfer of the patient from a critical care area and reliance on experienced interpretation.

Abdominal Injuries↗
PubMed1989

Blunt rupture of the myocardium.

With the evolution of regional trauma systems, patients with severe cardiac injury are arriving in emergency departments with the potential for survival. This paper reviews the 61 survivors of nonpenetrating rupture of the free walls of the myocardium reported in the English-language literature. The chambers were involved in the following frequency: right atrium, 36; left atrium, 11; right ventricle, 12; and left ventricle, four. Most victims were young males, and 85% were involved in motor vehicle accidents. Seventy percent had an admission systolic blood pressure less than 80 mm Hg, 78% had distended neck veins or a central venous pressure greater than 20 cm H2O, 67% had a widened mediastinum on admission chest roentgenogram, and 48% had fractures of the bony thorax. More than one hour elapsed before initiation of repair in 59%. Forty-eight percent of the repairs were performed via a median sternotomy. Cardiopulmonary bypass was used in only 10%.

Europe↗
PubMed1989

Transection of the inferior vena cava from blunt thoracic trauma: case reports.

Blunt thoracic trauma is a frequent cause of death in multiple trauma victims. Myocardial rupture may occur in up to 65% of patients who die with thoracic injuries. Two cases are presented with intrapericardial transection of the inferior vena cava, pericardial rupture, and myocardial rupture from blunt thoracic trauma. Both patients died.

Adult↗
PubMed1989

Left-sided perinephric hematoma associated with rupture of the left hemidiaphragm: a marker for renal artery injury.

Renal artery injury is an uncommon consequence of blunt abdominal trauma and probably is often missed. We recently saw three patients with rupture of the left hemidiaphragm associated with renal artery injury. The finding of a perinephric hematoma in a multiply injured patient with an ipsilateral diaphragmatic rupture prompted evaluation of the renal artery. With massive injury, the kidney may be displaced superiorly when the diaphragm ruptures, producing injury to the ipsilateral renal artery. This association has not been emphasized in the literature. The finding of a perinephric hematoma on the left should prompt full evaluation of the renal arteries if seen in association with diaphragmatic rupture.

Accidents, Traffic↗