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Biomedical subjects

Michael S O'Mara

Publications and source records attributed to Michael S O'Mara.

11 recordsLinked to original sources
PubMed2005

Results of a protocol of transfusion threshold and surgical technique on transfusion requirements in burn patients.

INTRODUCTION: Blood loss and high rates of transfusion in burn centers remains an area of ongoing concern. Blood use brings the risk of infection, adverse reaction, and immunosuppression. METHODS: A protocol to reduce blood loss and blood use was implemented. Analysis included 3-year periods before and after institution of the protocol. All patients were transfused for a hemoglobin below 8.0 gm/dL. RESULTS: Operations per admission did not change during the two time periods (0.78 in each). Overall units transfused per operation decreased from 1.56+/-0.06 to 1.25+/-0.14 units after instituting the protocol (p<0.05). Also, units transfused per admission decreased from 1.21+/-0.15 to 0.96+/-0.06 units of blood (p<0.05). This was noticed particularly in burns of less than 20% surface area, declining from 386 to 46 units after protocol institution, from 0.37 to 0.04 units per admission, and from 0.79 to 0.08 units per operation in this group of smallest burns. There was no change noted in the larger burns. CONCLUSIONS: This study suggests that a defined protocol of hemostasis, technique, and transfusion trigger should be implemented in the process of burn excision and grafting. This will help especially those patients with the smallest burns, essentially eliminating transfusion need in that group.

Blood Loss, Surgical↗
PubMed2005

A prospective, randomized evaluation of intra-abdominal pressures with crystalloid and colloid resuscitation in burn patients.

BACKGROUND: The volume of resuscitation in burn patients has been shown to correlate with intra-abdominal pressure (IAP). Limiting volume may reduce consequences of IAP and abdominal compartment syndrome. Colloid resuscitation has been previously shown to limit the volume required initially after burn. METHODS: Thirty-one patients were prospectively followed. Inclusion criteria were a burn of 25% total body surface area with inhalation injury or 40% total body surface area without. Patients received crystalloid (Parkland formula) or plasma resuscitation. IAP was measured by means of urinary bladder transduction. RESULTS: Mean age, area of burn, and baseline IAP were not different. Urine output was maintained. There was a greater increase in IAP with crystalloid (26.5 vs. 10.6 mmHg, p < 0.0001). Two patients in the plasma group developed IAP greater than 25 mmHg; only one patient in the crystalloid group maintained IAP less than 25 mmHg. More fluid volume was required with crystalloid resuscitation, 0.26 L/kg, versus 0.21 L/kg (p < 0.005). Correlation was seen in both groups between volume of fluid and IAP (crystalloid, r = 0.351; plasma, r = 0.657; all patients, r = 0.621). CONCLUSION: Plasma-resuscitated patients maintained an IAP below the threshold of complications of intra-abdominal hypertension. This appears to be a direct result of the decrease in volume required. Lower fluid volume regimens should be given consideration as the incidence and consequences of intra-abdominal hypertension in burn patients continue to be defined.

Abdomen↗
PubMed2004

Modified separation of parts as an intervention for intraabdominal hypertension and the abdominal compartment syndrome in a swine model.

Standard therapy for abdominal compartment syndrome is laparotomy. In many patients, laparotomy involves a recent incision; for others, volume of resuscitation may be the cause. The components separation technique allows difficult abdominal closure. The authors studied the effect of a modified separation of parts on abdominal compartment syndrome in an animal model. Eight pigs were instrumented for measurement of central venous pressure, mean arterial pressure, peak airway pressure, and intraabdominal pressure. Intraabdominal hypertension to 25 mmHg was established with intraperitoneal fluid infusion. Modified separation of parts was performed by sequential release of the abdominal wall layers. With increased intraabdominal pressure, mean arterial pressure (55.3 +/- 12.0 to 65.3 +/- 11.0), central venous pressure (7.7 +/- 2.4 to 13.3 +/- 6.9), and peak airway pressure (20.2 +/- 2.4 to 25.3 +/- 4.1; p < 0.05) also increased. Maximum intraabdominal pressure was 26.0 +/- 1.2 mmHg. Skin incision resulted in a decrease in intraabdominal pressure to 21.7 +/- 4.5, external oblique release to 18.3 +/- 3.9, internal oblique release to 13.2 +/- 4.0, and transversus muscle incision to 7.0 +/- 2.5 mmHg (p < 0.05). With completion of components separation, mean arterial pressure remained increased (63.2 +/- 16.9), central venous pressure decreased (6.8 +/- 3.6; p < 0.05), and peak airway pressure decreased (22.7 +/- 3.9; p < 0.05). Modified separation of parts technique effectively releases intraabdominal hypertension and reverses the physiologic derangements associated with abdominal compartment syndrome in the animal model.

Abdomen↗
PubMed2003

Abdominal compartment syndrome as a consequence of rectus sheath hematoma.

Abdominal compartment syndrome is a well-documented entity arising from multiple and various causes. The rise of intra-abdominal pressure by the increase in volume of the peritoneal and retroperitoneal contents has been shown in the resuscitation and evaluation of surgical patients. However, the incidence of constriction of the abdomen causing intra-abdominal hypertension is unknown. Previously limited to burn eschar and externally applied devices (such as MAST trousers), external compression leading to abdominal compartment syndrome has been a limited entity. We report the first documented case of an expansive abdominal wall mass, a rectus sheath hematoma, leading to impending abdominal compartment syndrome.

Abdomen↗
PubMed2002

The use of routine chest X-ray films after chest tube removal in postoperative cardiac patients.

BACKGROUND: The use of routine postoperative chest x-ray films (CXRs) for postoperative cardiac patients has been challenged, suggesting that only clinically indicated CXRs be obtained. The removal of chest tubes has been used as an indication for CXRs. Our hypothesis is that routine postoperative chest tube removal CXRs are not indicated in the asymptomatic postoperative cardiac patient. METHODS: Charts of 1,021 consecutive postoperative median sternotomy patients were reviewed, focusing on postoperative findings of CXRs, clinical evaluations, and interventions. Those who died prior to tube removal were excluded from the study. RESULTS: Tubes were removed on postoperative days 1 to 7 (average, 1.45 days). The two groups of patients were comparable in age, gender, procedure, and co-morbidity (p > .01). Seven hundred three patients underwent routine postoperative tube removal CXRs. Abnormal findings were present in 282 patients. Resultant therapeutic intervention was undertaken in 13 patients and 9 were symptomatic. No imaging after routine postoperative CXRs was conducted in 283 patients. These patients remained asymptomatic and required no intervention. Fourteen patients had clinically indicated CXRs after chest tube removal. Two of these patients had additional tubes placed, and 1 patient had follow-up films. In total, there was a 1.5% incidence of therapeutic intervention after chest tube removal. All patients were discharged without further sequelae of their tubes. CONCLUSIONS: Omission of routine postoperative chest tube removal CXRs in postoperative cardiac patients is safe. The removal of chest tubes in these patients is not an indication for CXRs.

Aged↗
PubMed2002

The use of tourniquets in the excision of unexsanguinated extremity burn wounds.

PURPOSE: Tangential excision of burns is complicated by blood loss. Tourniquet use decreases blood loss, but adequacy of excision has been questioned. An attempt was made to assess the value of not exsanguinating the limb prior to tourniquet inflation to improve visualization of bleeding points and subsequent engraftment. METHODS: Eleven excisions of bilateral extremity wounds were performed. One limb was excised without the benefit of a tourniquet, the other with tourniquet but without exsanguination. Tangential excision was performed, hemostasis achieved, and blood loss quantified. Engraftment of skin was assessed at first dressing change and at initial follow-up after discharge. RESULTS: Area of burn was the same, 4.8% with tourniquet, 5.1% without (P=0.38). Overall blood loss was less with tourniquet control, 100-259 cm(3) (P=0.002); as was blood loss per area, 0.19-0.58 cc/cm(2) (P=0.04). Graft take was similar, 98.2% early and 98.1% later with tourniquet, with 98.2 and 96.8% take without (P>0.1). CONCLUSIONS: Tourniquet use in the unexsanquinated extremity reduced blood loss without affecting engraftment.

Adolescent↗
PubMed2002

Laparoscopic reoperation for early complications of laparoscopic gastric bypass.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (LRYGBP) is a popular operation for morbid obesity. Early complications can be treated successfully with a laparoscopic approach. We reviewed our experience with laparoscopic re-exploration in the early postoperative period. METHODS: The initial 85 patients who underwent LRYGBP by two surgeons at a training hospital were reviewed. All patients who required re-exploration within the first 60 days postoperatively were considered. RESULTS: Nine patients underwent ten laparoscopic explorations. Mean BMI was 50 kg/m2. One patient underwent revision for proximal anastomotic obstruction at 58 days postoperatively. Three patients developed obstruction at the level of the transverse mesocolon secondary to cicatrix and required laparoscopic release of the scar tissue. Two patients required revision of the jejuno-jejunostomy. Internal hernia through the mesenteric defect at the level of the transverse mesocolon was the cause of bowel obstruction in two patients. One patient underwent lysis of adhesions between the left colon and the transverse mesocolon at 6 days postoperatively. One out of the ten laparoscopic re-explorations was negative for any findings. Eight patients recovered without further complications and one patient required endoscopic dilatations of the proximal anastomosis. CONCLUSION: In the course of treating morbid obesity with laparoscopic intervention, complications will arise. Laparoscopic exploration for early complications is a safe and feasible option.

Adult↗
PubMedDate not supplied

Instant cup of soup: design flaws increase risk of burns.

Prepackaged soups are a frequent cause of burn injury. We hypothesize that package design increases the risk for burn injury by affecting container stability. All pediatric scald burns caused by soup, between June 1997 and August 2004, were reviewed for burn and patient characteristics. Instant or "ready-to-eat" soups also were purchased. Safety statements and recommendations as to use of the microwave oven were documented. The height and the areas of the base and top were compared to the angle that a container would tip over on to its side. During the study period, 99 admissions and 80 outpatients were treated for burns caused by soup. Although the burn size was small (mean 5% TBSA) 22 patients required grafting. Of 13 different soups, 11 required the addition of hot water, and 2 were prepackaged for eating out of the container. Twelve containers had round bases and were tall and narrow, with one being shorter and rectangular. The measurements that correlated with the ease of tipping over were the base area, top area, and the ratio of height/base area. The most significant contributor to the ease of tipping over was height. Instant soups are packaged in containers that tend to be tall with a narrow base that predisposes them to being knocked over and spilled. Simple redesigning of instant soup packaging with a wider base and shorter height, along with the requirement for warnings about the risks of burns would reduce the frequency of soup burns.

Burns↗
PubMedDate not supplied

Hypothalamic-pituitary-adrenal axis response to sustained stress after major burn injury in children.

The hypothalamic-pituitary-adrenal (HPA) axis is responsible for stress response after injury, yet its function after severe burn injury in children is unclear. The purpose of this study was to define the effects of burn injury on the HPA axis and to evaluate the utility of total serum cortisol in measuring adrenal function in children with major burns in the 2 months after injury. Children ages 0 to 17 years who were admitted within 72 hours to our pediatric burn center with 20% TBSA or greater full-thickness burns were eligible for the study. Serum total cortisol, adrenocorticotropic hormone (ACTH), dehydroepiandrosterone, vasopressin, Pediatric Risk of Mortality (PRISM) score, serum albumin level, and electrolytes were obtained on admission and weekly for 8 weeks. An ACTH stimulation test (250 microg for children >2 years, 125 microg for children < or =2 years) was administered weekly at 8:00 am. Total serum cortisol was measured before and 60 minutes after the administration of ACTH. Twenty-five children with mean age 7.6 +/- 1.1 years and TBSA burn 41.8 +/- 3.8% were enrolled in the study. Baseline total serum cortisol was 12.4 +/- 0.7 microg/dl in the 8 weeks after injury and increased to 24.4 +/- 0.8 microg/dl after the administration of ACTH. Cortisol level did not correlate with PRISM score, albumin, vasopressin, ACTH, or mortality. Although the adrenal response to acute and chronic stress is intact after severe burn injury, the ACTH/adrenal feedback loop is disrupted. Random total serum cortisol measurements overestimate adrenal dysfunction; thus, ACTH stimulation testing should be used to assess adrenal function before the administration of exogenous steroids.

Adolescent↗
PubMedDate not supplied

Effects of a restrictive blood transfusion policy on outcomes in children with burn injury.

A restrictive blood transfusion policy decreases blood utilization and improves outcomes in critically ill adults, but the impact of a restrictive blood transfusion policy in critically ill children is unclear. The study purpose was to compare the effects of a restrictive with a traditional blood transfusion policy in children with major burn injury. A retrospective review of all blood transfusions administered in a pediatric burn center during a 5-year period was conducted. Children in the traditional group (January 1, 2000, to June 30, 2002), were transfused at a hemoglobin level of less than 10 g/dl. Children in the restrictive group (January 1, 2003, to June 30, 2005, 6 months after the adoption of a restrictive protocol) were transfused at a hemoglobin level of less than 7 g/dl. Patient groups were compared for demographics, ventilator requirements, blood transfusion number, transfusion costs, and outcomes. Of the 1140 patients studied, 266 (24%) received a total of 2577 units of blood. There was no difference in age, TBSA burn, sex, inhalation injury, or mortality between groups. Patients in the traditional group received more blood than the restrictive group (12.3 +/- 1.8 vs 7.2 +/- 1.2 units/patient, P < .001). The mean cost of blood per patient was $2781 for the traditional group and $1489 for the restrictive group. A restrictive transfusion policy in children with burn injury decreases the amount of blood transfused, does not adversely impact patient outcome, and results in significant cost savings to the institution.

Blood Transfusion↗