Racial disparities in surgical outcomes in patients with pancreatic ductal adenocarcinoma (PDAC) undergoing pancreas surgery

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Background: Previous studies have suggested disparity in PDAC survival in African American (AA) compared to non-AA patients. Pancreas surgery is associated with significant morbidity, and technical outcomes are known to impact survival; however, there is little reported data on surgical outcomes by race. We sought to evaluate the effect of race on surgical outcomes and survival in an urban tertiary care center for patients with PDAC undergoing pancreas surgery. Methods: A retrospective single-center analysis of PDAC patients undergoing pancreas resection between January 2013 and September 2021 was performed. Patient demographics, Clavien-Dindo (CD) complications, readmission, and mortality in the 30- and 90- day period were collected and stratified by race. Univariate and multivariate analyses were performed. Results: Among 180 patients, 145 (81%) were non-AA and 35 (19%) were AA. Demographic and pre-operative characteristics were found to be similar between the two groups. 30-day ED visits, postoperative pancreatic fistula (POPF), delayed gastric emptying (DGE), and intra-abdominal abscess (IAA) were found to be significant on univariate analysis in the AA cohort. On multivariate analysis, 30-day ED visit (OR 4.5; 95% CI 1.3-15.8; p = 0.02), POPF (OR 4.5; 95% CI 1.3-14.8; p = 0.015), and IAA (OR 4.4; 95% CI 1.12-17.3; p = 0.033) were still significantly higher in the AA cohort while DGE lost its significance. Median overall survival and disease-free survival showed no significant difference on Kaplan-Meier curves. There was no statistical difference in local, regional, or metastatic recurrence patterns between the two groups (distant metastasis 36% in non-AA and 37% in AA). Conclusions: AA undergoing pancreas surgery for PDAC were noted to have higher incidence of POPF and IAA as well as ED visits compared to non-AA patients. However, no significant difference was seen in reoperation rates, major CD complications, recurrences, or survival. Exploring tumor biology, and preoperative treatment algorithms may shed additional insight on the differences in surgical outcomes in this patient cohort.[Table: see text]

Local resection versus radical surgery for parathyroid carcinoma: A National Cancer Database analysis

INTRODUCTION

Parathyroid carcinoma (PC) is rare and often diagnosed incidentally after local resection (LR) for other indications. Although recommended treatment has traditionally been radical surgery (RS), more recent guidelines suggest that LR alone may be adequate. We sought to further investigate outcomes of RS versus LR for localized PC.

MATERIALS AND METHODS

PC patients from 2004 to 2015 with localized disease were identified from the National Cancer Database, then stratified by surgical therapy: LR or RS. Demographic and clinicopathologic data were compared. Cox proportional hazard models were constructed to estimate associations of variables with overall survival (OS). OS was estimated from time of diagnosis using Kaplan-Meier curves.

RESULTS

A total of 555 patients were included (LR = 522, RS = 33). The groups were comparable aside from LR patients having higher rates of unknown nodal status (66.9% versus 39.4%; p = 0.003). By multivariable analysis, RS did not have a significant association with OS (hazard ratio (HR) = 0.43, 95% confidence interval (95%CI) = 0.10, 1.83; p = 0.255), nor did positive nodal status (HR = 0.66, 95%CI = 0.09, 5.03; p = 0.692) and unknown nodal status (HR = 1.30, 95%CI = 0.78, 2.17; p = 0.311). There was no difference in OS between the LR and RS groups, with median survival not reached by either group at 10 years (median follow-up = 60.4 months; p = 0.20).

CONCLUSIONS

There was no difference in OS between LR and RS for localized PC. RS and nodal status may not impact survival as previously identified, and LR should remain a valid initial surgical approach. Future higher-powered studies are necessary to assess the effects of surgical approaches on morbidity and oncologic outcomes.

Neoadjuvant chemotherapy versus upfront resection in ampullary adenocarcinoma stratified by stage: A retrospective analysis using the National Cancer Database

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Background: Outcomes of a neoadjuvant therapy (NAT) strategy to treat ampullary adenocarcinoma (AAC) are unclear. Upfront resection (UR) (typically pancreaticoduodenectomy) with or without adjuvant therapy (AT) is currently the standard of care. We looked to assess outcomes of NAT followed by radical surgery for AAC. Methods: The NCDB was queried for ampullary carcinoma patients from 2004-2015. Patients with Stage I to III AAC who underwent radical surgery were included, and separated into NAT with surgery and UR groups. Demographic/clinical/pathologic data and their associations to survival were analyzed with univariate and multivariate cox proportional hazard models. Overall survival was estimated from time of diagnosis using Kaplan-Meier curves and compared using log-rank tests (LRT) (see table). Statistical analyses were performed using R version 3.5.1 with significance established at p < 0.05. Results: There was no difference in overall survival between the NAT (n = 47) and UR (n = 1521) groups, either as total groups (LRT p = 0.2), or when stratified by stage (stratified LRT p = 0.5). Rates of AT were higher in the UR group (p = 0.038). Receiving AT was significantly associated with improved survival (hazard ratio (HR) = 0.648), while positive nodal status (HR = 2.06), stage 3 disease (HR = 1.542), age > 65 (HR = 1.494), and male gender (HR = 1.241) were significantly associated with decreased overall survival by multivariate analysis. Conclusions: NAT does not offer a survival advantage over UR either overall or for stage-specific disease. This finding extended even to stage III disease, where NAT would theoretically offer greatest benefit. This study suggests that a NAT strategy is not preferable to UR for treatment of resectable AAC, regardless of stage. Higher powered study of NAT for AAC with controls for AT is warranted before discarding a NAT strategy. [Table: see text]

Neoadjuvant therapy for body and tail pancreatic adenocarcinoma: Propensity score matched analysis using the National Cancer Database

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Background: The role of neoadjuvant systemic therapy in the management of body and tail pancreatic ductal adenocarcinoma (PDAC) is unknown. The aim of our study was to investigate the outcomes associated with neoadjuvant therapy for early stage body and tail PDAC. Methods: The National Cancer Database (NCDB) was queried for stage I and II body and tail PDAC between 2006-2014. Groups were defined according to treatment sequencing strategies into an upfront resection group (UR), resection followed by adjuvant therapy (R+AT), neoadjuvant therapy followed by resection (NAT+R), and neoadjuvant therapy followed by resection and adjuvant therapy (NAT+R+AT). Patients who underwent neoadjuvant therapy followed by resection were matched by propensity score with patients who underwent upfront resection. Overall survival was compared using Kaplan-Meier method and Cox proportional hazards regression model. Results: 441 patients received NAT+R with or without AT compared to 1323 patient who underwent UR with or without AT. NAT+R had lower pathologic stage, lymph node positivity and a higher rate of margin negative resections compared to the matched UR cohort. In the propensity matched cohort, the median survival (MS) was higher in the neoadjuvant (NAT+R/NAT+R+AT) group compared to the upfront resection (UR/R+AT) group (28.6 vs. 22.9 mo; p<0.001). When further stratified by treatment sequencing the MS was longer in a NAT+R+AT cohort compared to the R+AT group (36.0 vs. 25.3 mo; p<0.05) (Table). However, there was no difference in MS between R+AT and NAT+R cohorts. On multivariable analysis, receipt of NAT represented an independent factor for survival (NAT+R+AT HR 0.41, 95% CI 0.32-0.54; NAT+R HR, 0.53, 95% CI 0.44-0.64; R+AT HR 0.61, 95% CI 0.53-0.70). Conclusions: There appears to be a survival benefit with neoadjuvant systemic therapy in patients with early stage body and tail PDAC. A systemic perioperative treatment sequencing approach (NAT+R+AT) appears to have the greatest survival benefit. [Table: see text]

MicroRNA-101 inhibits growth of epithelial ovarian cancer by relieving chromatin-mediated transcriptional repression of p21(waf¹/cip¹)

PURPOSE

MicroRNA-101 (miR-101) expression is negatively associated with tumor growth and proliferation in several solid epithelial cancers. Enhancer of zeste homolog 2 (EzH2) appears to be a functional target of miR-101. We explore the role of miR-101 and its interaction with EzH2 in epithelial ovarian carcinoma (EOC).

METHODS

In situ hybridization (ISH) for miR-101 was performed on EOC patient tissues and normal controls. EOC cell lines were transfected with miR-101 and subjected to growth analysis and clonogenic assays. Cell motility was assessed by Boyden chamber and wound-healing assays. P21(waf1/cip1) and EzH2 interaction was assessed by Chromatin Immunoprecipitation (ChIP) assay in MDAH-2774 cells. SCID mice were assessed for tumor burden after injection with miR-101 or control vector-treated MDAH-2774 cells.

RESULTS

ISH analysis revealed a decrease in miR-101 expression in EOC compared with normal tissue. MiR-101 re-expression in EOC cell lines resulted in increased apoptosis, decreased cellular proliferation, invasiveness, and reduced growth of tumor xenografts. CHIP assays revealed that re-expression of miR-101 inhibited the interaction of EzH2 with p21(waf1/cip1) promoter.

CONCLUSIONS

MiR-101 re-expression appears to have antitumor effects, providing a better understanding of the role of miR-101 in EOC.

Ritonavir blocks AKT signaling, activates apoptosis and inhibits migration and invasion in ovarian cancer cells

Background

Ovarian cancer is the leading cause of mortality from gynecological malignancies, often undetectable in early stages. The difficulty of detecting the disease in its early stages and the propensity of ovarian cancer cells to develop resistance to known chemotherapeutic treatments dramatically decreases the 5-year survival rate. Chemotherapy with paclitaxel after surgery increases median survival only by 2 to 3 years in stage IV disease highlights the need for more effective drugs. The human immunodeficiency virus (HIV) infection is characterized by increased risk of several solid tumors due to its inherent nature of weakening of immune system. Recent observations point to a lower incidence of some cancers in patients treated with protease inhibitor (PI) cocktail treatment known as HAART (Highly Active Anti-Retroviral Therapy).

Results

Here we show that ritonavir, a HIV protease inhibitor effectively induced cell cycle arrest and apoptosis in ovarian cell lines MDH-2774 and SKOV-3 in a dose dependent manner. Over a 3 day period with 20 μM ritonavir resulted in the cell death of over 60% for MDAH-2774 compared with 55% in case of SKOV-3 cell line. Ritonavir caused G1 cell cycle arrest of the ovarian cancer cells, mediated by down modulating levels of RB phosphorylation and depleting the G1 cyclins, cyclin-dependent kinase and increasing their inhibitors as determined by gene profile analysis. Interestingly, the treatment of ritonavir decreased the amount of phosphorylated AKT in a dose-dependent manner. Furthermore, inhibition of AKT by specific siRNA synergistically increased the efficacy of the ritonavir-induced apoptosis. These results indicate that the addition of the AKT inhibitor may increase the therapeutic efficacy of ritonavir.

Conclusion

Our results demonstrate a potential use of ritonavir for ovarian cancer with additive effects in conjunction with conventional chemotherapeutic regimens. Since ritonavir is clinically approved for human use for HIV, drug repositioning for ovarian cancer could accelerate the process of traditional drug development. This would reduce risks, limit the costs and decrease the time needed to bring the drug from bench to bedside.

Telomere maintenance in laser capture microdissection-purified Barrett's adenocarcinoma cells and effect of telomerase inhibition in vivo

PURPOSE

The aims of this study were to investigate telomere function in normal and Barrett's esophageal adenocarcinoma (BEAC) cells purified by laser capture microdissection and to evaluate the effect of telomerase inhibition in cancer cells in vitro and in vivo.

EXPERIMENTAL DESIGN

Epithelial cells were purified from surgically resected esophagi. Telomerase activity was measured by modified telomeric repeat amplification protocol and telomere length was determined by real-time PCR assay. To evaluate the effect of telomerase inhibition, adenocarcinoma cell lines were continuously treated with a specific telomerase inhibitor (GRN163L) and live cell number was determined weekly. Apoptosis was evaluated by Annexin labeling and senescence by beta-galactosidase staining. For in vivo studies, severe combined immunodeficient mice were s.c. inoculated with adenocarcinoma cells and following appearance of palpable tumors, injected i.p. with saline or GRN163L.

RESULTS

Telomerase activity was significantly elevated whereas telomeres were shorter in BEAC cells relative to normal esophageal epithelial cells. The treatment of adenocarcinoma cells with telomerase inhibitor, GRN163L, led to loss of telomerase activity, reduction in telomere length, and growth arrest through induction of both the senescence and apoptosis. GRN163L-induced cell death could also be expedited by addition of the chemotherapeutic agents doxorubicin and ritonavir. Finally, the treatment with GRN163L led to a significant reduction in tumor volume in a subcutaneous tumor model.

CONCLUSIONS

We show that telomerase activity is significantly elevated whereas telomeres are shorter in BEAC and suppression of telomerase inhibits proliferation of adenocarcinoma cells both in vitro and in vivo.

Lipopolysaccharide activation of pericyte's Toll-like receptor-4 regulates co-culture permeability

BACKGROUND

Pericytes (PCs) have a synergistic relationship with endothelial cells (MVEC) in regulating capillary permeability. PCs express Toll-like receptor-4 (TLR-4). We hypothesize one mechanism of MVEC/PC co-culture permeability is regulated through lipopolysaccharide (LPS) activation of pericyte TLR-4.

METHODS

Rat PCs were harvested and cultured. PCs were transfected with siRNA targeted to TLR-4. Western blotting was used to confirm gene silencing of TLR-4. A previously described co-culture permeability assay was performed after LPS treatment.

RESULTS

Western blot confirmed successful silencing of TLR-4 in PCs, which was sustained for 7 days. A dose- and time-dependent effect of LPS on albumin clearance was seen in MVEC/PC co-cultures. Co-cultures with TLR-4 silenced in PCs eliminated the LPS dose-dependent increase in albumin clearance.

CONCLUSIONS

TLR-4 regulates pericyte mediated capillary leak seen with LPS exposure. Our TLR-4 silencing model can be used to further investigate TLR-4's role in pericyte mediated capillary leak.

Lipopolysaccharide up-regulates heat shock protein expression in rat lung pericytes

BACKGROUND

Heat shock proteins (HSP) function as molecular chaperones, participating in protein folding and maturation throughout the cell. Serum HSPs may correlate with acute lung injury. Pericytes are perivascular cells located abluminally from endothelial cells, and play a regulatory role in capillary leak. It is our hypothesis that pericytes express HSP 60 and HSP 70, and these HSPs are up-regulated in response to lipopolysaccharide (LPS).

METHODS

Rat microvascular lung pericytes were isolated and cultured. Cells from passages three to five were used and treated with LPS (control, 10 ng/mL, and 100 ng/mL) for either 4 or 18 h. Immunoblotting and real-time PCR were used to analyze the presence and quantity of HSP 60 and HSP 70.

RESULTS

Immunoblotting revealed the presence of HSP 60 and HSP 70 in control pericytes. After 4 h of treatment with LPS (10 ng/mL and 100 ng/mL), no increase in protein expression of HSP 60 or HSP 70 was seen. However, after 18 h an increase in protein expression of HSP 60 and HSP 70 was seen. Real-time PCR demonstrated the presence of HSP 60 mRNA and HSP 70 mRNA in control pericytes. An increase in mRNA was seen after 18 h of LPS treatment, but not after 4 h.

CONCLUSIONS

This study provides the first in vitro evidence that rat lung pericytes express HSP 60 and HSP 70. HSP 60 and HSP 70 are up-regulated after 18 h of LPS exposure. Pericyte heat shock protein expression may contribute to the lung's response seen in sepsis.

Solid-pseudopapillary tumors of the pancreas: case report and literature review

Solid pseudopapillary tumors (SPT) of the pancreas are rare neoplasms of low malignant potential that mostly affect young women. These tumors are of unclear pathogenesis, are slow growing, and can become considerably large before causing symptoms. Complete resection is curative in most cases. This is the case of a 39-year-old African-American woman undergoing evaluation for Roux-en-Y gastric bypass, who was found to have a pancreatic mass. Image-guided biopsy revealed SPT. The patient underwent complete excision of the tumor and had an open Roux-en-Y gastric bypass performed concurrently. The patient had an uneventful postoperative course. A review of the literature is presented.

Cytokine production in lipopolysaccharide-exposed rat lung pericytes

BACKGROUND

Vessels of the pulmonary microvasculature are composed of two cell types: endothelial cells and pericytes. Pericytes are crucial to the development of capillary leak and pulmonary edema seen in acute respiratory distress syndrome (ARDS). Pericytes express toll-like receptor-4, and is upregulated in response to lipopolysaccharide (LPS). The objective of this study was to evaluate secretory cytokine production by rat microvascular pericytes. It is our hypothesis that pericytes secrete interleukin (IL)-1B, IL-6, and tumor necrosis factor (TNF)-A in response to LPS.

METHODS

Rat lung pericytes (RLPs) were isolated and grown either alone or in coculture with rat endothelial cells. Cells from passages 3 to 5 were used and treated with LPS (control, 10 ng/mL, and 100 ng/mL) for varying amounts of time. Immunoblotting and reverse transcriptase polymerase chain reaction (RT-PCR) was used for detection and quantification of NF-kB. Enzyme-linked immunosorbent assay and RT-PCR were used for detection and quantification of cytokines.

RESULTS

The protein and mRNA for NF-kB was detected in RLPs. Additionally, NF-kB mRNA increased with exposure to LPS. The supernatant of RLPs exposed to LPS contained IL-1B, and IL-1B increased in a time- and dose-dependant manner. An increase in mRNA for IL-1B, IL-6, and TNF-A was seen in a dose-dependant fashion. Cocultures produced significantly less IL-1B when exposed to similar concentrations of LPS.

CONCLUSIONS

Pericytes contain the machinery necessary, and produce pro-inflammatory cytokines. Cocultures manufacture less IL-1B then pericytes alone, which is similar to previous coculture observations. Pericyte activation and cytokine production may play a role in capillary leak seen in gram-negative sepsis.

Vascular endothelial growth factor modulates contractile response in microvascular lung pericytes

BACKGROUND

Pericytes are capillary support cells that may play a role in regulating permeability by their contractile responses. Vascular endothelial growth factor (VEGF) may play a role in the increased permeability found in sepsis and other inflammatory conditions. The purpose of this study was to evaluate the role of VEGF in regulating pericyte contraction.

METHODS

Rat microvascular lung pericytes were isolated according to previously described methods and cultured on collagen gel matrices. Cells were exposed to VEGF (10, 100, and 1000 pg/mL) for varying time periods (0, 10, 30, 60, and 120 minutes). The gels were released and their contractile responses digitally quantified.

RESULTS

At all doses, VEGF induced initial pericyte relaxation (contraction 85% to 90% of controls; P < .001). This was followed-up by increased and sustained contraction (107% to 120% of controls; P < .01).

CONCLUSIONS

VEGF modifies the contractile response of microvascular lung pericytes. This mechanism may play a role in the increased permeability demonstrated in inflammatory states.

TNF-alpha and IL-1beta increase pericyte/endothelial cell co-culture permeability

BACKGROUND

Pericytes (PC) have a unique synergistic relationship with microvascular endothelial cells (MVEC) in the regulation of capillary permeability. This study investigates the effect of TNF-alpha, IL-1beta, and IL-6 on the microvasculature by measuring changes in PC contractility, and also, albumin permeability across MVEC/PC co-cultures.

MATERIALS AND METHODS

Semi-permeable inserts were plated first with rat lung MVEC and then PCs (on the fourth day) at a ratio of 10:1 MVEC/PC. On day 5, 50 ng/ml of TNF-alpha, IL-1beta, and IL-6 were added with or without a secretory phospholipase A(2)-IIA (sPLA(2)-IIA) inhibitor for 24 h. After treatments, albumin clearances were quantified. For measuring contractility, PCs were cultured on collagen matrices and exposed for 24 h to TNF-alpha, IL-1beta, and IL-6 at 1 ng/ml, 10 ng/ml, and 50 ng/ml with/without inhibitors for sPLA(2)-IIA, phospholipase A(2) (PLA(2)), and cyclooxygenase-II (COX-II). After treatments, the surface area of the collagen disks was digitally quantified.

RESULTS

TNF-alpha and IL-1beta significantly increased albumin clearance in MVEC/PC co-cultures (P < 0.05) and induced dose-dependent relaxation of PCs (P < 0.05). PC relaxation was completely attenuated with the sPLA(2)-IIA and pLA(2) inhibitors; the COX-II inhibitor provided partial blockade. IL-6 had no effect on PC contractility or permeability.

CONCLUSION

TNF-alpha and IL-1beta directly increased microvascular permeability in co-cultures. They also induced relaxation of PCs through a sPLA(2)-IIA dependent mechanism. Interestingly, IL-6 had no effect, although its presence in high levels has been demonstrated in inflamed lungs. These findings may help elucidate the significance of PC in regulating the capillary response to various pro-inflammatory cytokines.

Endothelial cells protect against lipopolysaccharide-induced caspase-3–mediated pericyte apoptosis in a coculture system

BACKGROUND

Cells that comprise the pulmonary capillary walls, the pericytes and endothelial cells, may undergo apoptosis in inflammatory states. This study examined the effects of lipopolysaccharide (LPS) on apoptosis in pericytes and endothelial cells, both individually and grown together in a coculture system.

METHODS

Pericytes and endothelial cells were isolated and cultured separately and in coculture as previously described. The cells were subsequently exposed to LPS for 12, 24, 48, and 72 hours. The cellular contents were then examined by Western blot analysis for products of apoptosis. TUNEL staining was also performed to analyze for apoptosis.

RESULTS

Pericytes alone exposed to LPS showed increased levels of p11 and p17, which are activated fragments of capase-3, a cysteine effector protease involved in cleaving cytoskeletal and nuclear proteins to induce apoptosis. When grown in coculture with endothelial cells and exposed to LPS in coculture but harvested independently, pericytes showed decreased levels of p11 and p17 and increased levels of Bcl-xL, an antiapoptotic protein that protects the integrity of mitochondria, and prevents cytochrome c release and subsequent caspase-9 activation.

CONCLUSIONS

In response to LPS, pericytes undergo apoptosis involving the caspase-3 pathway. Endothelial cells may decrease this effect through the expression of a soluble mediator.

Prognostic determinants in duodenal injuries

A retrospective review of 222 consecutive patients with duodenal injuries admitted to an urban Level 1 Trauma Center who subsequently underwent laparotomy during the period July 1980 to April 2002 was performed in an effort to elucidate factors associated with mortality, infectious morbidity, and length of stay in these patients. Predictably, the patients were predominantly male (92.7%) and young (mean age, 31.6 years). The overall mortality rate was 22.5 per cent, with a mortality rate of 18 per cent seen in the first 48 hours. Penetrating trauma was suffered by 88.3 per cent of the patients. Multivariate analysis revealed the performance of a thoracotomy, initial emergency department (ED) systolic blood pressure (SBP) <90 mm Hg, final operating room (OR) core body temperature less than 35 degrees C, and presence of a splenic injury to be the most important predictors of mortality (all P < 0.05). Mortality in the patients undergoing a resuscitative thoracotomy was 88.9 per cent versus 13.3 per cent in those patients not requiring thoracotomy. An initial SBP in the ED <90 was associated with a 46 per cent mortality rate, as compared with 4 per cent in those patients not in shock. A final OR core body temperature of less than 35 degrees C led to a 60 per cent mortality rate versus 8.3 per cent for warmer patients. Patients with a concomitant splenic injury were noted to have a 62.5 per cent mortality rate; those without had a 19.4 per cent mortality rate. The mean length of stay among survivors greater than 48 hours was 16.0 +/- 24.7 days. Univariate analyses revealed lowest OR core body temperature below 35 degrees C, initial OR SBP <90, presence of infection, >5 transfusions, initial ED SBP <90, final OR core temperature <35 degrees C, colon injury, spleen injury, and an injury severity score (ISS) >25 all to be significantly associated with increased length of stay. Multivariate analysis revealed an initial operating room blood pressure of less than 90 mm Hg systolic, the presence of an infection, and greater than 5 blood transfusions to be the factors most significantly correlated with increased length of stay (all P < 0.02). Of 182 patients surviving 48 hours, 98 (54%) developed an infection. Fifty-seven (31%) patients were noted to have wound-related infections, 92 (51%) patients had nosocomial infections, and 50 (27%) patients had both types. The presence of an abdominal arterial injury, an ISS >25, pancreatic injury, and lowest OR core body temperature <35 degrees C were the factors identified on multivariate analysis most significantly correlated with infectious morbidity (all P < 0.05). This data suggests that early efforts to prevent shock and rapidly control bleeding are the most likely efforts to reduce mortality rates in these patients. Those patients with duodenal injury presenting in shock or requiring a thoracotomy for resuscitation did poorly. Splenic injury was the associated injury found on multivariate analysis to be most closely associated with increased mortality. Early control of bleeding and the prevention of infection provide the most significant opportunity for decreasing length of stay. Infections are common with duodenal injuries, and aggressive surveillance should especially be performed in those patients with an abdominal arterial injury, an ISS >25, pancreatic injury, or lowest OR core body temperature <35 degrees C.

Prognostic Determinants in Duodenal Injuries

A retrospective review of 222 consecutive patients with duodenal injuries admitted to an urban Level 1 Trauma Center who subsequently underwent laparotomy during the period July 1980 to April 2002 was performed in an effort to elucidate factors associated with mortality, infectious morbidity, and length of stay in these patients. Predictably, the patients were predominantly male (92.7%) and young (mean age, 31.6 years). The overall mortality rate was 22.5 per cent, with a mortality rate of 18 per cent seen in the first 48 hours. Penetrating trauma was suffered by 88.3 per cent of the patients. Multivariate analysis revealed the performance of a thoracotomy, initial emergency department (ED) systolic blood pressure (SBP) <90 mm Hg, final operating room (OR) core body temperature less than 35°C, and presence of a splenic injury to be the most important predictors of mortality (all P < 0.05). Mortality in the patients undergoing a resuscitative thoracotomy was 88.9 per cent versus 13.3 per cent in those patients not requiring thoracotomy. An initial SBP in the ED <90 was associated with a 46 per cent mortality rate, as compared with 4 per cent in those patients not in shock. A final OR core body temperature of less than 35°C led to a 60 per cent mortality rate versus 8.3 per cent for warmer patients. Patients with a concomitant splenic injury were noted to have a 62.5 per cent mortality rate; those without had a 19.4 per cent mortality rate. The mean length of stay among survivors greater than 48 hours was 16.0 ± 24.7 days. Univariate analyses revealed lowest OR core body temperature below 35°C, initial OR SBP <90, presence of infection, >5 transfusions, initial ED SBP <90, final OR core temperature <35°C, colon injury, spleen injury, and an injury severity score (ISS) >25 all to be significantly associated with increased length of stay. Multivariate analysis revealed an initial operating room blood pressure of less than 90 mm Hg systolic, the presence of an infection, and greater than 5 blood transfusions to be the factors most significantly correlated with increased length of stay (all P < 0.02). Of 182 patients surviving 48 hours, 98 (54%) developed an infection. Fifty-seven (31%) patients were noted to have wound-related infections, 92 (51%) patients had nosocomial infections, and 50 (27%) patients had both types. The presence of an abdominal arterial injury, an ISS >25, pancreatic injury, and lowest OR core body temperature <35°C were the factors identified on multivariate analysis most significantly correlated with infectious morbidity (all P < 0.05). This data suggests that early efforts to prevent shock and rapidly control bleeding are the most likely efforts to reduce mortality rates in these patients. Those patients with duodenal injury presenting in shock or requiring a thoracotomy for resuscitation did poorly. Splenic injury was the associated injury found on multivariate analysis to be most closely associated with increased mortality. Early control of bleeding and the prevention of infection provide the most significant opportunity for decreasing length of stay. Infections are common with duodenal injuries, and aggressive surveillance should especially be performed in those patients with an abdominal arterial injury, an ISS >25, pancreatic injury, or lowest OR core body temperature <35°C.

Evaluation of academic and community surgery clerkships at a Midwestern medical school

BACKGROUND

The equivalency of surgical clerkship experience between academic and community sites is an issue that is assessed with difficulty. We examined the objective performance of 222 medical students after completion of the 8-week surgical clerkship. Six different consecutive semesters were analyzed. There were two objective examinations reviewed, the National Board of Medical Examiners' subject examination and the surgical subportion of the Objective Structured Clinical Examination (OSCE) given at the end of the third year.

METHODS

Medical students were classified into three separate groups based on the site of their surgical clerkship. The medical students were in either academic (100), community (79), or combined (academic and community) (43) locations. Medical student performance on the subject examination and OSCE was examined after completion of the general surgical clerkship. Single-factor analysis of variance testing was done to compare each of the three groups with respect to subject examination test score, or OSCE score. Significance was defined as P < 0.05.

RESULTS

The combined group scored highest on the subject examination (73.6%). The community group scored highest on the OSCE (80.7%). However, no statistical significance exists between the three groups with regard to subject examination (P = NS) or OSCE (P= NS). Subject examination scores did not correlate with OSCE scores (r = 0.095). Objective measurements of surgical subject examination and OSCE were not statistically different between academic, community, and academic and community surgical clerkship participants.

CONCLUSIONS

No statistically significant differences exist between the three groups with regards to OSCE failure rates, but the small amount of failures may have caused Type 2 error. Surgical clinical skills as tested by an OSCE and surgical knowledge as tested by a subject examination are equally attained by an academic or community surgical clerkship.

Predictors of Mortality in Patients with Traumatic Diaphragmatic Rupture and Associated Thoracic and/or Abdominal Injuries

This is a retrospective review of 731 patients sustaining diaphragmatic trauma over a 22 year period (1980–2002) at an urban level I trauma center. Patients had an average injury severity score (ISS) of 22 ± 12. The mortality rate (MR) was 23 per cent (168/731). There were a total of 460 left-sided diaphragmatic injuries (L-TDR), 263 right-sided diaphragmatic injuries (R-TDR), and 8 bilateral diaphragmatic injuries (B-TDR). There were no significant differences in mortality with L-TDR versus R-TDR. Shotgun wounds had the highest MR (42%) ( P = 0.0028). Emergency thoracotomies were performed in 31 per cent (225) with a 62 per cent (140) MR. Bilateral thoracotomies had a significantly higher MR of 85 per cent (33/39) compared to the 58 per cent (107/186) for unilateral thoracotomies ( P = 0.0028). Multivariate analysis revealed the most significant independent predictors of mortality to be the revised trauma score, transfusion of pRBCs > 10 units, and need for thoracotomy (P < 0.0001). The infection rate was 41 per cent. Multivariate analysis revealed blunt trauma, blood transfusions, ISS, and pancreatic injury as the most significant independent predictors of infection ( P < 0.001). The initial physiologic presentation of the patient and the severity of hemorrhagic shock are the primary determinants for survival. Prompt identification of associated injuries with rapid control of bleeding is paramount to survival.

Inhibition of Heme Oxygenase-1 in Microvascular Lung Pericytes Diminishes at High Concentrations of an Inflammatory Mediator

Post-traumatic inflammation and sepsis induce changes in the lung microvasculature causing increased permeability. Pericytes, contractile cells positioned abluminally to endothelial cells, play a role in regulating this response. An in vitro model of microvascular lung pericytes (MLP) was used to investigate the effect of inhibiting heme oxygenase-1 (HO-1), a stress-induced enzyme, in the presence of varying levels of lipopolysaccharide (LPS), a mediator in the initiation of inflammation, on pericyte contractility. Rat MLP were cultured on collagen gel matrices. Cells were exposed to three concentrations of LPS in the presence of zinc protoporphyrin IX (ZnPP-9), a known inhibitor of HO-1. After 24 hours, the surface area of the collagen disks was quantified, thereby measuring pericyte contraction. ZnPP-9 caused a significant attenuation of the LPS-induced relaxation of the pericytes ( P ≤ 0.003). The effects of ZnPP-9, however, depended on the concentration of LPS to which the pericytes were exposed. Greater concentrations of LPS decrease the attenuating power of ZnPP-9. The inhibition of HO-1 diminished MLP relaxation triggered by LPS. The effect of ZnPP-9, however, is dependent on the concentration of LPS to which the MLP are exposed, indicating its saturation. ZnPP-9 may antagonize the microvascular response to trauma.

Inhibition of heme oxygenase-1 in microvascular lung pericytes diminishes at high concentrations of an inflammatory mediator

Post-traumatic inflammation and sepsis induce changes in the lung microvasculature causing increased permeability. Pericytes, contractile cells positioned abluminally to endothelial cells, play a role in regulating this response. An in vitro model of microvascular lung pericytes (MLP) was used to investigate the effect of inhibiting heme oxygenase-1 (HO-1), a stress-induced enzyme, in the presence of varying levels of lipopolysaccharide (LPS), a mediator in the initiation of inflammation, on pericyte contractility. Rat MLP were cultured on collagen gel matrices. Cells were exposed to three concentrations of LPS in the presence of zinc protoporphyrin IX (ZnPP-9), a known inhibitor of HO-1. After 24 hours, the surface area of the collagen disks was quantified, thereby measuring pericyte contraction. ZnPP-9 caused a significant attenuation of the LPS-induced relaxation of the pericytes (P < or = 0.003). The effects of ZnPP-9, however, depended on the concentration of LPS to which the pericytes were exposed. Greater concentrations of LPS decrease the attenuating power of ZnPP-9. The inhibition of HO-1 diminished MLP relaxation triggered by LPS. The effect of ZnPP-9, however, is dependent on the concentration of LPS to which the MLP are exposed, indicating its saturation. ZnPP-9 may antagonize the microvascular response to trauma.

Predictors of mortality in patients with traumatic diaphragmatic rupture and associated thoracic and/or abdominal injuries

This is a retrospective review of 731 patients sustaining diaphragmatic trauma over a 22 year period (1980-2002) at an urban level I trauma center. Patients had an average injury severity score (ISS) of 22 +/- 12. The mortality rate (MR) was 23 per cent (168/731). There were a total of 460 left-sided diaphragmatic injuries (L-TDR), 263 right-sided diaphragmatic injuries (R-TDR), and 8 bilateral diaphragmatic injuries (B-TDR). There were no significant differences in mortality with L-TDR versus R-TDR. Shotgun wounds had the highest MR (42%) (P = 0.0028). Emergency thoracotomies were performed in 31 per cent (225) with a 62 per cent (140) MR. Bilateral thoracotomies had a significantly higher MR of 85 per cent (33/39) compared to the 58 per cent (107/186) for unilateral thoracotomies (P = 0.0028). Multivariate analysis revealed the most significant independent predictors of mortality to be the revised trauma score, transfusion of pRBCs > 10 units, and need for thoracotomy (P < 0.0001). The infection rate was 41 per cent. Multivariate analysis revealed blunt trauma, blood transfusions, ISS, and pancreatic injury as the most significant independent predictors of infection (P < 0.001). The initial physiologic presentation of the patient and the severity of hemorrhagic shock are the primary determinants for survival. Prompt identification of associated injuries with rapid control of bleeding is paramount to survival.

The Roles of Cyclic Adenosine Monophosphate- and Cyclic Guanosine Monophosphate-Dependent Protein Kinase Pathways in Hydrogen Peroxide-Induced Contractility of Microvascular Lung Pericytes

BACKGROUND

Sepsis and posttraumatic inflammatory processes are accompanied by definite changes in microvascular permeability, particularly in the lung. These permeability changes may occur because of damaged regulatory mechanisms at the level of the capillary wall. Pericytes are adventitial cells located within the basement membrane of capillaries. These cells contain multiple cytoplasmic processes that envelope endothelial cells, and are consequently thought to stabilize capillary walls and participate in microcirculation and endothelial cell permeability. Data from this laboratory and other laboratories have confirmed that pericytes are contractile cells, adding to the evidence that pericytes may influence or help regulate capillary permeability. We have already determined that hydrogen peroxide (H2O2) causes dose-dependent relaxation in microvascular lung pericytes (MLPs) at 10 minutes and, conversely, dose-dependent contraction at 30 minutes. It is the aim of this study to determine the mechanism of this biphasic contractile response. Specifically, we will determine whether cyclic adenosine monophosphate (cAMP)- or cyclic guanosine monophosphate (cGMP)-dependent protein kinase intracellular pathways are responsible for the hydrogen peroxide-induced contractility of MLPs.

METHODS

Rat MLPs were isolated by previously published protocol and cultured on collagen gel matrices. MLPs were pretreated with either ODQ, a soluble guanylate cyclase inhibitor (100 mumol/L), for 15 minutes; GKIP, a protein kinase G inhibitor (100 mumol/L), for 1 hour; SQ22536, an adenylate cyclase inhibitor (100 mumol/L), for 15 minutes; or H89, a protein kinase A inhibitor (10 mumol/L), for 1 hour. Hydrogen peroxide was then introduced to each MLP culture at 10 mumol/L, 100 mumol/L, and 1 mmol/L. After each of these treatments, the surface area of the collagen gels was digitally quantified at 10 and 30 minutes.

RESULTS

SQ22536 attenuated both relaxation at 10 minutes and the contraction seen at 30 minutes for all concentrations of H2O2. H89 caused a marked basal relaxation and prevented the cells from contracting at 30-minute exposures to all concentrations of H2O2. Both ODQ and GKIP attenuated the relaxation at 10 minutes but had no affect on the later contraction.

CONCLUSION

The cGMP-dependent protein kinase pathway is a mechanism for H2O2-induced relaxation of MLPs. Up-regulation of cAMP and cGMP is responsible for early H2O2-induced relaxation and late contraction. Protein kinase A (cAMP-dependent protein kinase pathway) may be an important intracellular signaling protein in the H2O2-induced contraction of MLPs or may be unable to down-regulate cAMP once inhibited. This evidence further supports the concept that there are separate intracellular pathways that regulate divergent cellular responses. This idea parallels the clinical concept of reversible and irreversible dysfunction of cellular processes in shock, and that the cellular dysfunction is initiated by separate intracellular pathways.

Lipopolysaccharide (LPS) enhancement of outward current in lung pericytes

Patch clamp methods were used to study the effect of lipopolysaccharide (LPS), an endotoxin produced by gram-negative bacteria, on voltage-dependent outward current of lung pericytes. Pericytes are located in capillary walls and may mediate pathological changes in microvascular hemodynamics and permeability that accompany endotoxin-mediated pulmonary edema. Previous studies have shown that LPS reduces lung pericyte contractility. Lung pericytes exhibited a voltage-dependent outward current, presumed to be K+ current, and this current increased in magnitude in response to LPS. Cells incubated for 48 hr without LPS (control) had an average peak current at 50 mV of 101 pA (n = 5 cells), whereas cells incubated with 100 mg/ml LPS had an average peak current of 927 pA (n = 9 cells, P<0.01 compared to control). When held at 50 mV for 50 msec, net outward current decreased in control cells by 10.7% and in LPS-treated cells by 2.6% (P<0.05). The increased activation of outward current in LPS-treated cells may be due to a previously inactive potassium channel and may mediate LPS-induced relaxation of the lung pericyte.

End-tidal CO2-derived values during emergency trauma surgery correlated with outcome: a prospective study

BACKGROUND

The purpose of this study was to determine whether end-tidal carbon dioxide (PETCO) derived variables assist in evaluating the adequacy of resuscitation during emergency surgery for trauma.

METHODS

This was a prospective study of end-tidal derived variables and outcome in 106 trauma patients in an urban Level I trauma center.

RESULTS

The patients who lived (compared with those who died) had higher final end-tidal Pco levels, lower arterial-end tidal CO differences (Pa-ET)CO, and a decreased alveolar dead space ratio (p < 0.001). The best survival rates were with a PETCO > 27 mm Hg, a (Pa-ET)CO < or = 9 mm Hg, and 96% (56 of 58) for an alveolar dead space ratio < or = 0.20 (p < 0.001). An inappropriately high or "excess Paco also correlated with a decreased (Pa-ET)CO and poorer prognosis. If, after the initial resuscitation, the PETCO -derived values did not achieve these "optimal" levels, survival was significantly reduced.

CONCLUSION

During emergency trauma surgery, the PETCO and its derived values help to predict outcome and may be used to identify patients needing more aggressive resuscitation.

Pericytes augment the capillary barrier in in vitro cocultures

Most in vitro studies of capillary permeability focus on endothelial cell (MVEC) monolayers and ignore the second cell that forms the capillary wall: the microvascular pericyte (PC). We describe a model to study the permeability characteristics of MVEC, PC, and MVEC:PC cocultures.

METHODS

Semipermeable culture inserts were coated with collagen and then plated with early passage bovine pulmonary MVEC. On Day 3, bovine pulmonary PC were added at concentrations to approximate MVEC:PC ratios of 1:1, 5:1, and 10:1. Electrical resistance was measured on subsequent days and fluorescently labeled (FITC) albumin was used in a permeability assay to calculate an albumin clearance for each culture.

RESULTS

The results for electrical resistance measurements and albumin assays showed a similar pattern. Resistance for endothelial cell monolayers was significantly higher and albumin permeability was significantly lower than that of controls. Addition of pericytes at a 10:1 and 5:1 ratios increased the permeability barrier compared to endothelial cells alone, although these cultures were not significantly different from one another. Cocultures at a 1:1 ratio had the best barrier, significantly better than all other cultures.

CONCLUSIONS

Endothelial cell monolayers are an inadequate model of the microcirculation. As PC form a key component of the capillary wall in vivo and as addition of PC to MVEC monolayers in vitro, optimally at a 1:1 ratio, increase their barrier effect to large and small molecules, we believe it is necessary to include both cells in future in vitro studies.

Infectious Complications following Duodenal and/or Pancreatic Trauma

Patients with pancreatic and/or duodenal trauma often have a high incidence of infectious complications. In this study we attempted to find the most important risk factors for these infections. A retrospective review of the records of 167 patients seen over 7 years (1989 through 1996) at an urban Level I trauma center for injury to the duodenum and/or pancreas was performed. Fifty-nine patients (35%) had isolated injury to the duodenum (13 blunt, 46 penetrating), 81 (49%) had isolated pancreatic trauma (18 blunt, 63 penetrating), and 27 (16%) had combined injuries (two blunt, 25 penetrating). The overall mortality rate was 21 per cent and the infectious morbidity rate was 40 per cent. The majority of patients had primary repair and/or drainage as treatment of their injuries. Patients with pancreatic injuries (alone or combined with a duodenal injury) had a much higher infection rate than duodenal injuries. The patients with duodenal injuries had significantly lower penetrating abdominal trauma indices, number of intra-abdominal organ injuries, and incidence of hypothermia. On multivariate analysis independent factors associated with infections included hypothermia and the presence of a pancreatic injury. Although injuries to the pancreas and duodenum often coexist it is the pancreatic injury that contributes most to the infectious morbidity.

Infectious complications following duodenal and/or pancreatic trauma

Patients with pancreatic and/or duodenal trauma often have a high incidence of infectious complications. In this study we attempted to find the most important risk factors for these infections. A retrospective review of the records of 167 patients seen over 7 years (1989 through 1996) at an urban Level I trauma center for injury to the duodenum and/or pancreas was performed. Fifty-nine patients (35%) had isolated injury to the duodenum (13 blunt, 46 penetrating), 81 (49%) had isolated pancreatic trauma (18 blunt, 63 penetrating), and 27 (16%) had combined injuries (two blunt, 25 penetrating). The overall mortality rate was 21 per cent and the infectious morbidity rate was 40 per cent. The majority of patients had primary repair and/or drainage as treatment of their injuries. Patients with pancreatic injuries (alone or combined with a duodenal injury) had a much higher infection rate than duodenal injuries. The patients with duodenal injuries had significantly lower penetrating abdominal trauma indices, number of intra-abdominal organ injuries, and incidence of hypothermia. On multivariate analysis independent factors associated with infections included hypothermia and the presence of a pancreatic injury. Although injuries to the pancreas and duodenum often coexist it is the pancreatic injury that contributes most to the infectious morbidity.

Lipopolysaccharide induces relaxation in lung pericytes by an iNOS-independent mechanism

Lipopolysaccharide (LPS)-regulated contractility in pericytes may play an important role in mediating pulmonary microvascular fluid hemodynamics during inflammation and sepsis. LPS has been shown to regulate inducible nitric oxide (NO) synthase (iNOS) in various cell types, leading to NO generation, which is associated with vasodilatation. The purpose of this study was to test the hypothesis that LPS can regulate relaxation in lung pericytes and to determine whether this relaxation is mediated through the iNOS pathway. As predicted, LPS stimulated NO synthesis and reduced basal tension by 49% (P < 0.001). However, the NO synthase inhibitors N (omega)-nitro-L-arginine methyl ester, aminoguanidine, and N (omega)-monomethyl-L-arginine did not block the relaxation produced by LPS. In fact, aminoguanidine and N (omega)-monomethyl-L-arginine potentiated the LPS response. The possibility that NO might mediate either contraction or relaxation of the pericyte was further investigated through the use of NO donor compounds; however, neither sodium nitroprusside nor S-nitroso-N-acetylpenicillamine had any significant effect on pericyte contraction. The inhibitory effect of aminoguanidine on LPS-stimulated NO production was confirmed. This ability of LPS to inhibit contractility independent of iNOS was also demonstrated in lung pericytes derived from iNOS-deficient mice. This suggests the presence of an iNOS-independent but as yet undetermined pathway by which lung pericyte contractility is regulated.

Effects of vasoactive mediators on the rat lung pericyte: quantitative analysis of contraction on collagen lattice matrices

Pericytes are contractile cells of the microvasculature which may contribute to the hypotension and increase in permeability that are present during inflammation and late-stage sepsis. The purpose of this study was to examine the contractile effects, if any, of septic modulators on the lung pericyte. Contractile effects were qualitatively examined using a previously developed silicone rubber method. This study further demonstrates a quantitative method for measuring the contraction of lung pericytes cultured on a collagen lattice. Contraction was measured by the change in collagen matrix area in response to vasoactive stimuli. Bradykinin and serotonin significantly increased contraction in a dose-dependent manner, with a maximum increase in contraction twice that of control. Forskolin and adenosine caused relaxation, also in a significant dose-dependent manner, with a maximum decrease in contraction of 80 and 30-40%, respectively. Histamine had no effect on contractility in either the silicone rubber or the collagen lattice assay. These results show that the lung pericyte, like the retinal pericyte, is a contractile cell and can be stimulated to contract or relax in vitro by the presence of certain inotropic agents present during inflammation and sepsis. These responses may play a role in microvascular regulation.

CD4 cell counts as a prognostic factor of major abdominal surgery in patients infected with the human immunodeficiency virus

OBJECTIVE

To measure the prognostic utility of helper T-cell (CD4) counts in human immunodeficiency virus (HIV)-infected patients undergoing major abdominal surgery.

DESIGN

Retrospective case series.

SETTING

Three university-affiliated hospitals.

PATIENTS

Forty-three HIV-infected patients undergoing major abdominal surgery.

MAIN OUTCOME MEASURES

Morbidity and mortality rates with respect to CD4 cell counts.

RESULTS

Nineteen of 32 patients who had CD4 cell counts less than 0.20 X 10(9)/L (200 cells/microL) suffered major complications compared with 2 of 11 patients who had CD4 cell counts greater than 0.20 x 10(9)/L (200 cells/microL) (P=.03). Perioperative mortality was 38% for patients with CD4 cell counts less than 0.20 x 10(9)/L, and was 9% for those with CD4 cell counts greater than 0.20 x 10(9)/L (P=.13). Six months postoperatively, mortality rates were 47% and 9%, respectively (P=.03). Of patients with septic processes perioperatively (n=12), mortality was 75%, and was 19% (P=.009) for those with nonseptic processes (n=31). Nine patients had HIV-related intra-abdominal pathologic conditions at laparotomy. Mortality was 56% perioperatively (P=.13) and 88% after 6 months (P=.001). Sixty-eight percent of patients who received blood product transfusions developed complications, whereas only 7% of those who did not receive transfusions developed complications (P<.001). Overall mortality and morbidity rates were 37% and 49%, respectively. Patients with morbidity had lower CD4 cell counts (median, 0.034 x 10(9)/L) than those without complications (median, 0.102 x 10(9)/L) (P=.02). Similarly, patients who died had lower CD4 cell counts (median, 0.031 x 10(9)/L vs 0.088 x 10(9)/L) (P=.05).

CONCLUSIONS

Patients with acquired immunodeficiency syndrome-defining CD4 cell counts undergoing major abdominal surgery developed more complications and had poorer outcomes at 6-month follow-up compared with HIV-infected patients whose CD4 cell counts were greater than 0.20 x 10(9)/L (200 cells/microL). A perioperative septic process and HIV-related pathologic conditions seen at laparotomy are also associated with worse outcomes.

Basic science curriculum during residency: justification based on in-training examination scores

The American Board of Surgery is increasing its emphasis on competency in surgical basic science as part of residency training. The 1991 American Board of Surgery In-Training Examination (ABSITE) contained 135 questions designated as basic science to assess residents' knowledge. We reviewed the separate progression of scores in clinical and basic sciences at Wayne State University (WSU) surgical residency and nationally through the 1991 ABSITE report. Regression analysis of WSU data yielded a slope (% correct answers per postgraduate year) of 5.3 for clinical and 2.4 for basic science scores (P < 0.001 by t-statistic applied to regression slopes). These data imply a progression of knowledge during residency but at a significantly slower rate for basic science. The national data confirm this trend, although we were unable to evaluate it statistically. This situation illustrates the need for organized teaching of clinically relevant basic science as part of a residency curriculum.

Oxygen transport-dependent splanchnic metabolism in the sepsis syndrome

OBJECTIVE

Total body oxygen consumption (VO2) may be pathologically oxygen delivery (DO2)-dependent in critically ill patients exhibiting the sepsis syndrome. This observation has been used to infer the presence of occult tissue or organ ischemia that potentially can be eradicated by augmenting DO2. We examined this hypothesis by determining the VO2-DO2 relationship and lactate metabolism in the splanchnic region.

DESIGN

Before and after intervention trial.

SETTING

University-affiliated Veterans Affairs Medical Center, Allen Park, Mich.

PATIENTS

Eighteen surgical patients exhibiting the sepsis syndrome.

INTERVENTION

Systemic and splanchnic oxygen exchange and lactate uptake measurements before and after augmentation of DO2 with blood transfusion.

MAIN OUTCOME MEASURES

Changes in oxygen exchange and lactate metabolism.

RESULTS

The splanchnic VO2 index rose 9% in association with a 26% regional DO2 index increase indicating an oxygen transport dependency (P < .05). Splanchnic O2 extraction (0.47 +/- 0.04) was significantly greater than the mean systemic level (0.31 +/- 0.02) and showed a greater decline following DO2 index augmentation (0.41 +/- 0.04 vs 0.28 +/- 0.03, respectively). However, splanchnic lactate uptake was not changed significantly in response to the increased DO2 index.

CONCLUSIONS

Although splanchnic oxygen transport dependency and elevated extraction ratios suggest the presence of regional ischemia that should be relieved with an increased DO2 index, the observed changes in lactate uptake do not support this conclusion. The significance of the VO2-DO2 relationship, its role in the pathophysiology of the sepsis syndrome, and its place in the clinical care of the septic surgical patient are in doubt.

Endoscopic management of nonvariceal gastrointestinal bleeding

Endoscopic management of upper gastrointestinal bleeding has been expanded from a purely diagnostic role to a therapeutic role in many patients. In addition to controlling active bleeding, it is an option in a patient who is clinically at a high risk of rebleeding, or in patients who have peptic ulcers with visible vessels or stigmata indicating high risk. Several methods have been studied, and currently the most useful include thermal cautery with the heater probe or bipolar electrocoagulation, and injection using epinephrine and/or sclerosants. Endoscopic hemostasis can effect permanent control of bleeding in many patients, but should be considered complementary to conventional surgical control in other patients, where temporary control to stabilize the patient is a desired end.

Blood transfusion and oxygen consumption in surgical sepsis

OBJECTIVE

To evaluate the use of serum lactic acid values to predict flow-dependent increases in oxygen consumption (VO2) in response to increasing oxygen delivery (DO2) after blood transfusion in surgical sepsis.

DESIGN

Prospective study.

SETTING

Tertiary care, trauma center.

PATIENTS

Twenty-one patients, postsurgical or posttrauma, judged septic by defined criteria.

INTERVENTIONS

Serum lactic acid concentrations, DO2, and VO2 were measured before and after transfusion therapy.

MEASUREMENTS AND MAIN RESULTS

Overall, the DO2 increased from 532 +/- 146 to 634 +/- 225 (SD) mL/min.m2 (p less than .001), and the VO2 increased from 145 +/- 39 to 160 +/- 56 mL/min.m2 (p = .02). These changes occurred with an Hgb increase from 9.3 +/- 1.1 to 10.7 +/- 1.5 g/dL (p less than .001). The patients were grouped by their pretransfusion serum lactic acid values. In those patients with normal (less than 1.6 mmol/dL) serum lactic acid (n = 10), DO2 increased from 560 +/- 113 to 676 +/- 178 mL/min.m2 (p less than .02), and VO2 increased from 150 +/- 25 to 183 +/- 46 mL/min.m2 (p less than .02). However, in the increased serum lactic acid group (n = 17), VO2 was not significantly changed after transfusion (143 +/- 46 to 146 +/- 58 mL/min.m2) despite increased DO2 (515 +/- 163 to 609 +/- 251 mL/min.m2, p less than .01).

CONCLUSIONS

Blood transfusion can be used to augment DO2 and VO2 in septic surgical patients. Increased serum lactic acid values do not predict patients who will respond. The absence of lactic acidosis should not be used in this patient population to justify withholding blood transfusions to improve flow-dependent VO2. Patients who have increased lactate concentrations may have a peripheral oxygen utilization defect that prevents improvement in VO2 with increasing DO2.

Oxygen saturation monitoring during endoscopy

The role of monitoring during endoscopy is not clearly defined. We have prospectively investigated continuous arterial oxygen saturation (SaO2) monitoring in 326 patients undergoing upper endoscopy (EGD) and 90 undergoing colonoscopy. Automated blood pressure recording was evaluated in 278 of these patients. SaO2 desaturation (less than 90%) occurred in 17.8% of patients undergoing EGD and 12.9% undergoing colonoscopy. Systolic blood pressure abnormalities (greater than 200 or less than 90 mmHg) occurred in 19.8% of EGD patients and 19.6% of colonoscopy patients. Treatment based on these abnormalities was required in 4.3% of patients during EGD and 8.8% during colonoscopy. A history of pulmonary or cardiac disease predicted increased risk during colonoscopy, while cardiac disease and age 60 years or above predicted desaturation during EGD. Pulse oximetry and automated blood pressure monitoring was especially valuable during endoscopy in the elderly and patients with cardiac or pulmonary disease. It may be used as a guide to therapeutic intervention and to avert major cardiopulmonary complications.

Upper GI bleeding in an urban hospital. Etiology, recurrence, and prognosis

Acute upper gastrointestinal bleeding (UGIB) continues to be a common cause of hospital admission and morbidity and mortality. This study reviews 469 patients admitted to a surgical service of an urban hospital. There were 562 total admissions because 53 patients were readmitted 93 times (recurrence rate, 20%). The most common causes of bleeding, all endoscopically diagnosed, included acute gastric mucosal lesion (AGML) (135 patients, 24%), esophageal varices (EV) (121 patients, 22%), gastric ulcer (108 patients, 19%), duodenal ulcer (78 patients, 14%), Mallory-Weiss tear (61 patients, 11%), and esophagitis (15 patients, 3%). Nonoperative therapy was sufficient in 504 cases (89.5%). Endoscopic treatment was used in 144 cases. Operations were performed in 58 cases (10.5%), including 29% of ulcers. Emergency operations to control hemorrhage were required in only 2.5% of all cases. The rate of major surgical complications was 11% and the mortality rate was 5.2%. There were 58 deaths (12.6%), with 36 deaths directly attributable to UGIB. Factors correlating with death include shock at admission (systolic blood pressure less than 80), transfusion requirement of more than five units, and presence of EV (all p less than 0.001). Most cases of UGIB can be treated without operation, including endoscopic treatment, when diagnostic endoscopy establishes the source. Subsequent operation in selected patients can be done with low morbidity and mortality rates.