- Email: [email protected]
QS411. Laparotomy Attenuates Lipopolysaccharide Induced Duodenogastric Bile Acid Reflux and Gastric Bleeding
ASSOCIATION FOR ACADEMIC SURGERY AND SOCIETY OF UNIVERSITY SURGEONS—ABSTRACTS 431 were taken using the FLIR (Wilsonville, OR) camera model SC640. Image analysis was carried out using the ThermaCAM Quickview software. The images were compared with respect to the size of a median temperature and the area of greatest temperature. Results: Representative images from the end of the equilibration (MAP⫽76 T ⫽33.9C), shock (MAP⫽46, T⫽31.2C) and resuscitation (MAP⫽113, T⫽31.7C) periods are shown below:
Resuscitation
Equilibration
Shock
The core temperature of the animal diminished in shock and recovered partially with resuscitation. The area of greatest temperature 91.4-92.0°F is labeled bright green. Image E shows bright green prominently and there is only a small amount in the S image. The R image has no bright green in spite of the restoration of blood. The caudad portion of the E image appears as green with blue testicles. In the S image the caudad portion is emitting less IR as shown by the blue as opposed to green color and the cooler temperature of the testicles is designated by black. In the R image some of the caudad portion is green but not to the degree shown in the E image. The testicles remain black with some blue mixed in. Similar results were found in the other three experiments. Conclusion: IR imaging shows promise as a means of assessing the metabolic function of patients as determined by perfusion as well as metabolic dysfunction. With IR metabolic function before during and after shock can be detailed to various sectors of the body surface. The infusion of shed blood does not result in the complete restoration of normal metabolism QS411. LAPAROTOMY ATTENUATES LIPOPOLYSACCHARIDE INDUCED DUODENOGASTRIC BILE ACID REFLUX AND GASTRIC BLEEDING. Jeremy L. Ward, Benjamin A. Delano, Elizabeth Mercer, David W. Mercer; UT Medical School at Houston, Houston, TX Background: Intra-abdominal infection causes ileus and may require laparotomy for source control. In rats, intraperitoneal lipopolysaccharide (LPS) from E. coli, the most frequent pathogen encountered in these infections, causes duodenogastric bile reflux and gastric bleeding. However, the effects of laparotomy on these endpoints are unknown. It was our hypothesis that laparotomy would exacerbate bile reflux and gastric bleeding from LPS. Methods: Male rats were given either saline or LPS (20 mg/kg ip). One hour later, rats received isoflurane anesthesia with or without laparotomy and were sacrificed 4 hours later. Gastric fluid was analyzed for volume, pH, total hemoglobin content, and bile acid content. Data are mean ⫾ SEM (ANOVA; n ⱖ 5). Results: LPS caused significant accumulation of alkaline fluid containing bile and blood when compared to saline treated rats. Laparotomy significantly diminished LPS induced bile reflux and gastric bleeding, but not luminal alkalinization when compared to LPS rats not undergoing laparotomy.
432 ASSOCIATION FOR ACADEMIC SURGERY AND SOCIETY OF UNIVERSITY SURGEONS—ABSTRACTS Conclusion: These data indicate that laparotomy does not exacerbate the deleterious effects that LPS has on the stomach, but in fact, renders the stomach less susceptible to injury as evident by the reduction in bleeding. Further investigation into the mechanism(s) responsible for these effects are warranted. QS412. ISOVOLEMIC PLASMA RESUSCITATION DURING SHOCK. Ernest A. Gonzalez, David W. Mercer, Rosemary A. Kozar; University of Texas-Houston, Houston, TX Introduction: The use of plasma in a ratio of 1:1 with packed red blood cells has recently been shown to decrease mortality in severely injured patients presenting in shock and requiring massive transfusion. The mechanism for this effect is unknown. Because the gut is believed to play a major role in the pathogenesis of multiple organ failure and survival following shock, we hypothesized that plasma may attenuate shock-induced gut dysfunction. Methods: SpragueDawley rats were subjected to shock by superior mesenteric artery occlusion (SMAO) for 60 minutes followed by equal volume resuscitation with either plasma or Lactated Ringers (LR) at 10 cc/kg and compared to no resuscitation (SMAO alone) or shams (n⫽8/group). After 6 hours of resuscitation, ileum was harvested for measurement of gut injury (histology, Chiu score 0-5), edema (wet:dry ratio) or intestinal transit (mean geometric center). Blood was obtained at the time of sacrifice for PT, PTT, and INR. Results are presented as mean ⫾ SEM, ANOVA. Results: Resuscitation with plasma decreased gut injury and edema compared to no resuscitation and shams, effects similar in magnitude to that seen with equal volume LR. However, plasma enhanced intestinal transit compared to LR and no resuscitation. Coagulation parameters were normal for all groups.
Injury Edema Transit
Shams
SMAO
LR
Plasma
0.6 ⫾ 0.2a 4.3 ⫾ 0.3a 5.5 ⫾ 0.2a
4.0 ⫾ 0.3b 4.6 ⫾ 0.1b 3.5 ⫾ 0.6b
3.0 ⫾ 0.2c 4.9 ⫾ 0.1c 4.2 ⫾ 0.4b
3.0 ⫾ 0.3c 4.8 ⫾ 0.1c 4.7 ⫾ 0.2c
Conclusion: Compared to standard crystalloid resuscitation, isovolemic plasma resuscitation during shock does not afford additional protection to the ischemic gut in a model of gut IR. Further investigations into the mechanisms responsible for plasma’s survival advantage are warranted.
TRANSPLANT/IMMUNOLOGY IV: CLINICAL, TOLERANCE, IMMUNE MECHANISMS QS413. ESTIMATING THE POTENTIAL FOR ORGAN DONATION AFTER CARDIAC DEATH IN AN URBAN LEVEL I TRAUMA CENTER. David J. Ciesla, Christine T. Trankiem, Jimmy A. Light, Jack A. Sava; Washington Hospital Center, Washington, DC Background: As organ transplantation has grown increasingly safe and more effective, the demand for transplants has outpaced the supply of available organs. This disparity has renewed interest in donation after cardiac death (DCD) particularly after nontraumatic cardiac deaths. Early posttraumatic deaths represent another potential source for transplantable organs. The Level I trauma center with its immediately available surgical services is uniquely positioned to begin organ preservation in patients that fail initial postinjury resuscitation. A postinjury DCD program was previously implemented at our institution with community support but withered due to lack of consistent organ placement. With the increasing demand for organs, we undertook this study to estimate the number of potential posttraumatic DCD opportunities in an urban Level I trauma center.
Methods: Our hospital is an ACS/COT verified academic Level I trauma center and regional referral center for a compact geographical region of approximately 5 million people. The trauma registry was queried for patients evaluated by the trauma service over a 4 year period ending December 2006. Madrid Criteria were modified to include death within 24 hours of admission, age ⬍ 50, witnessed arrest, and CPR initiated and maintained within 15 min of arrest. Results: 9064 patients were admitted to the Trauma Receiving Unit over the study period; 580 (6.4%) died, 459 (5%) died within 24 hours of admission. Of the 459 patients that died within 24 hours, 218 (50% of early deaths) were younger than 50, had no abdominal injuries, and met CPR criteria and would thus be considered candidates for initiation of organ preservation. Conclusions: Approximately 50% of early traumatic deaths are potential candidates for initiation of organ preservation. Based on previous experience with traumatic DCD, we expect 70% of these to be suitable donor candidates. This would add approximately 39 donors per year increasing donor volume by 178%. The trauma resuscitation team is a key component to the development of a postinjury DCD program since organ preservation must be initiated within 30 minutes of cardiac arrest. QS414. GENETIC VARIANTS IN MAJOR HISTOCOMPATIBILITY COMPLEX-LINKED GENES ASSOCIATE WITH PEDIATRIC LIVER TRANSPLANT REJECTION. Rakesh Sindhi1, Brandon Higgs2, Daniel Weeks1; 1 University of Pittsburgh, Pittsburgh, PA; 2Childrens Hospital of Pittsburgh, Pittsburgh, PA Background/Aims: Limited access to large samples and independent replication cohorts precludes genome-wide association (GWA) studies of rare but complex traits. To localize candidate genes in an on-going study utilizing a family-based GWA approach, a novel exploratory analysis was first tested on 1,776 major histocompatibility complex single nucleotide polymorphisms (SNPs) in 240 DNA samples from 80 children with primary liver transplantation (LTx), and their biological parents. Methods/Results: Initially, 57 SNPs with large differences (p⬍0.05) in minor allele frequencies were selected, when parents of children with early rejection (Rejectors) were compared with parents of Non-Rejectors. In subsequent hypothesistesting of selected SNPs, the gamete competition statistic identified the minor allele G (ancestral allele T) of the HLA-DOA SNP, rs9296068, as being significantly different (p⫽0.018) in parent-tochild transmission between outcome groups. Subsequent simple association testing confirmed over- and under-transmission of rs9296068 based on 1) the most significant differences between outcome groups, of 1776 SNPs tested (p⫽0.002), and 2) allele (G) frequencies that were greater among Rejectors (51.4 vs. 36.8%, p⫽0.015), and lower among Non-Rejectors (26.8 vs. 36.8%, p⫽0.074), compared with 400 normal control Caucasian children. Conclusions: The minor allele of the HLA-DOA SNP, rs9296068, is significantly associated with LTx rejection. Since B-cell function differentiates Rejector and Non-Rejector phenotypes after pediatric LTx, and the HLA-DOA gene identified by rs9296068 downmodulates B-cell antigen-presentation selectively, a regulatory role is suggested for this gene and its associated pathway in pediatric LTx rejection. Validation of this new concept requires independent replication and functional studies. QS415. CARDIOVASCULAR AND BLOOD CHEMISTRY RESPONSES IN A MODEL OF ACUTE BRAIN DEATH IN RATS. Brandon C. Cain, Ryan T. Hurt, Paul J. Matheson, El Rasheid R. Zakaria, Richard N. Garrison; University of Louisville, Louisville, KY Introduction: Brain death in organ donors triggers a characteristic response: 1) altered homeostasis of central hemodynamics and hormonal function; 2) exaggerated systemic inflammatory response; and 3) end-organ microcirculatory dysfunction and tissue hypoperfusion.
Resuscitation
Equilibration
Shock
The core temperature of the animal diminished in shock and recovered partially with resuscitation. The area of greatest temperature 91.4-92.0°F is labeled bright green. Image E shows bright green prominently and there is only a small amount in the S image. The R image has no bright green in spite of the restoration of blood. The caudad portion of the E image appears as green with blue testicles. In the S image the caudad portion is emitting less IR as shown by the blue as opposed to green color and the cooler temperature of the testicles is designated by black. In the R image some of the caudad portion is green but not to the degree shown in the E image. The testicles remain black with some blue mixed in. Similar results were found in the other three experiments. Conclusion: IR imaging shows promise as a means of assessing the metabolic function of patients as determined by perfusion as well as metabolic dysfunction. With IR metabolic function before during and after shock can be detailed to various sectors of the body surface. The infusion of shed blood does not result in the complete restoration of normal metabolism QS411. LAPAROTOMY ATTENUATES LIPOPOLYSACCHARIDE INDUCED DUODENOGASTRIC BILE ACID REFLUX AND GASTRIC BLEEDING. Jeremy L. Ward, Benjamin A. Delano, Elizabeth Mercer, David W. Mercer; UT Medical School at Houston, Houston, TX Background: Intra-abdominal infection causes ileus and may require laparotomy for source control. In rats, intraperitoneal lipopolysaccharide (LPS) from E. coli, the most frequent pathogen encountered in these infections, causes duodenogastric bile reflux and gastric bleeding. However, the effects of laparotomy on these endpoints are unknown. It was our hypothesis that laparotomy would exacerbate bile reflux and gastric bleeding from LPS. Methods: Male rats were given either saline or LPS (20 mg/kg ip). One hour later, rats received isoflurane anesthesia with or without laparotomy and were sacrificed 4 hours later. Gastric fluid was analyzed for volume, pH, total hemoglobin content, and bile acid content. Data are mean ⫾ SEM (ANOVA; n ⱖ 5). Results: LPS caused significant accumulation of alkaline fluid containing bile and blood when compared to saline treated rats. Laparotomy significantly diminished LPS induced bile reflux and gastric bleeding, but not luminal alkalinization when compared to LPS rats not undergoing laparotomy.
432 ASSOCIATION FOR ACADEMIC SURGERY AND SOCIETY OF UNIVERSITY SURGEONS—ABSTRACTS Conclusion: These data indicate that laparotomy does not exacerbate the deleterious effects that LPS has on the stomach, but in fact, renders the stomach less susceptible to injury as evident by the reduction in bleeding. Further investigation into the mechanism(s) responsible for these effects are warranted. QS412. ISOVOLEMIC PLASMA RESUSCITATION DURING SHOCK. Ernest A. Gonzalez, David W. Mercer, Rosemary A. Kozar; University of Texas-Houston, Houston, TX Introduction: The use of plasma in a ratio of 1:1 with packed red blood cells has recently been shown to decrease mortality in severely injured patients presenting in shock and requiring massive transfusion. The mechanism for this effect is unknown. Because the gut is believed to play a major role in the pathogenesis of multiple organ failure and survival following shock, we hypothesized that plasma may attenuate shock-induced gut dysfunction. Methods: SpragueDawley rats were subjected to shock by superior mesenteric artery occlusion (SMAO) for 60 minutes followed by equal volume resuscitation with either plasma or Lactated Ringers (LR) at 10 cc/kg and compared to no resuscitation (SMAO alone) or shams (n⫽8/group). After 6 hours of resuscitation, ileum was harvested for measurement of gut injury (histology, Chiu score 0-5), edema (wet:dry ratio) or intestinal transit (mean geometric center). Blood was obtained at the time of sacrifice for PT, PTT, and INR. Results are presented as mean ⫾ SEM, ANOVA. Results: Resuscitation with plasma decreased gut injury and edema compared to no resuscitation and shams, effects similar in magnitude to that seen with equal volume LR. However, plasma enhanced intestinal transit compared to LR and no resuscitation. Coagulation parameters were normal for all groups.
Injury Edema Transit
Shams
SMAO
LR
Plasma
0.6 ⫾ 0.2a 4.3 ⫾ 0.3a 5.5 ⫾ 0.2a
4.0 ⫾ 0.3b 4.6 ⫾ 0.1b 3.5 ⫾ 0.6b
3.0 ⫾ 0.2c 4.9 ⫾ 0.1c 4.2 ⫾ 0.4b
3.0 ⫾ 0.3c 4.8 ⫾ 0.1c 4.7 ⫾ 0.2c
Conclusion: Compared to standard crystalloid resuscitation, isovolemic plasma resuscitation during shock does not afford additional protection to the ischemic gut in a model of gut IR. Further investigations into the mechanisms responsible for plasma’s survival advantage are warranted.
TRANSPLANT/IMMUNOLOGY IV: CLINICAL, TOLERANCE, IMMUNE MECHANISMS QS413. ESTIMATING THE POTENTIAL FOR ORGAN DONATION AFTER CARDIAC DEATH IN AN URBAN LEVEL I TRAUMA CENTER. David J. Ciesla, Christine T. Trankiem, Jimmy A. Light, Jack A. Sava; Washington Hospital Center, Washington, DC Background: As organ transplantation has grown increasingly safe and more effective, the demand for transplants has outpaced the supply of available organs. This disparity has renewed interest in donation after cardiac death (DCD) particularly after nontraumatic cardiac deaths. Early posttraumatic deaths represent another potential source for transplantable organs. The Level I trauma center with its immediately available surgical services is uniquely positioned to begin organ preservation in patients that fail initial postinjury resuscitation. A postinjury DCD program was previously implemented at our institution with community support but withered due to lack of consistent organ placement. With the increasing demand for organs, we undertook this study to estimate the number of potential posttraumatic DCD opportunities in an urban Level I trauma center.
Methods: Our hospital is an ACS/COT verified academic Level I trauma center and regional referral center for a compact geographical region of approximately 5 million people. The trauma registry was queried for patients evaluated by the trauma service over a 4 year period ending December 2006. Madrid Criteria were modified to include death within 24 hours of admission, age ⬍ 50, witnessed arrest, and CPR initiated and maintained within 15 min of arrest. Results: 9064 patients were admitted to the Trauma Receiving Unit over the study period; 580 (6.4%) died, 459 (5%) died within 24 hours of admission. Of the 459 patients that died within 24 hours, 218 (50% of early deaths) were younger than 50, had no abdominal injuries, and met CPR criteria and would thus be considered candidates for initiation of organ preservation. Conclusions: Approximately 50% of early traumatic deaths are potential candidates for initiation of organ preservation. Based on previous experience with traumatic DCD, we expect 70% of these to be suitable donor candidates. This would add approximately 39 donors per year increasing donor volume by 178%. The trauma resuscitation team is a key component to the development of a postinjury DCD program since organ preservation must be initiated within 30 minutes of cardiac arrest. QS414. GENETIC VARIANTS IN MAJOR HISTOCOMPATIBILITY COMPLEX-LINKED GENES ASSOCIATE WITH PEDIATRIC LIVER TRANSPLANT REJECTION. Rakesh Sindhi1, Brandon Higgs2, Daniel Weeks1; 1 University of Pittsburgh, Pittsburgh, PA; 2Childrens Hospital of Pittsburgh, Pittsburgh, PA Background/Aims: Limited access to large samples and independent replication cohorts precludes genome-wide association (GWA) studies of rare but complex traits. To localize candidate genes in an on-going study utilizing a family-based GWA approach, a novel exploratory analysis was first tested on 1,776 major histocompatibility complex single nucleotide polymorphisms (SNPs) in 240 DNA samples from 80 children with primary liver transplantation (LTx), and their biological parents. Methods/Results: Initially, 57 SNPs with large differences (p⬍0.05) in minor allele frequencies were selected, when parents of children with early rejection (Rejectors) were compared with parents of Non-Rejectors. In subsequent hypothesistesting of selected SNPs, the gamete competition statistic identified the minor allele G (ancestral allele T) of the HLA-DOA SNP, rs9296068, as being significantly different (p⫽0.018) in parent-tochild transmission between outcome groups. Subsequent simple association testing confirmed over- and under-transmission of rs9296068 based on 1) the most significant differences between outcome groups, of 1776 SNPs tested (p⫽0.002), and 2) allele (G) frequencies that were greater among Rejectors (51.4 vs. 36.8%, p⫽0.015), and lower among Non-Rejectors (26.8 vs. 36.8%, p⫽0.074), compared with 400 normal control Caucasian children. Conclusions: The minor allele of the HLA-DOA SNP, rs9296068, is significantly associated with LTx rejection. Since B-cell function differentiates Rejector and Non-Rejector phenotypes after pediatric LTx, and the HLA-DOA gene identified by rs9296068 downmodulates B-cell antigen-presentation selectively, a regulatory role is suggested for this gene and its associated pathway in pediatric LTx rejection. Validation of this new concept requires independent replication and functional studies. QS415. CARDIOVASCULAR AND BLOOD CHEMISTRY RESPONSES IN A MODEL OF ACUTE BRAIN DEATH IN RATS. Brandon C. Cain, Ryan T. Hurt, Paul J. Matheson, El Rasheid R. Zakaria, Richard N. Garrison; University of Louisville, Louisville, KY Introduction: Brain death in organ donors triggers a characteristic response: 1) altered homeostasis of central hemodynamics and hormonal function; 2) exaggerated systemic inflammatory response; and 3) end-organ microcirculatory dysfunction and tissue hypoperfusion.