R. Neal Garrison

Intensive surveillance of femoropopliteal-tibial autogenous vein bypasses improves long-term graft patency and limb salvage

OBJECTIVE The authors determined the impact of an intensive surveillance program of autogenous vein bypasses on patency and limb salvage. SUMMARY BACKGROUND DATA Surveillance protocols of vein bypasses can identify graft-threatening lesions to permit elective revisions before thrombosis. The authors compared follow-up based on clinically indicated procedures with intensive surveillance. METHODS From 1985 to 1994, 615 autogenous vein bypasses (454 in situ, 161 reversed/composite) to popliteal (n = 169) and tibial (n = 446) arteries were performed for critical limb ischemia (n = 507), claudication (n = 88), and popliteal aneurysm (n = 20). Intensive surveillance of autogenous vein bypasses consisted of ankle brachial index and duplex scan with graft velocities measured at 1 month, 3 months, 6 months, and every 6 months subsequently. After surgery 317 bypasses had intensive surveillance, 222 bypasses were clinically indicated for follow-up, and 76 bypasses were excluded because follow-up or patency was less than 31 days. RESULTS Primary patency at 5 years was similar for bypasses treated by intensive surveillance (56%) and those treated with clinically indicated procedures (67%). Secondary patency and limb salvage at 5 years was significantly improved (p < 0.02) for bypasses followed by intensive surveillance (80% and 94%) compared with clinically indicated procedures (67% and 73%). Revision of patent bypasses was higher (p < 0.000001) for bypasses treated by intensive surveillance (61 of 70, 87%) compared with those treated with clinically indicated procedures (9 of 34, 26%). Secondary patency at 2 years was significantly higher (p < 0.02) for revision of patent bypasses (79%) compared with thrombosed bypasses (55%). CONCLUSIONS Long-term autogenous vein bypass patency and limb salvage is significantly improved by intensive surveillance, permitting identification and correction of graft threatening lesions before thrombosis.

Intestinal blood flow is restored with glutamine or glucose suffusion after hemorrhage

Intestinal blood flow has been shown to be impaired after resuscitated hemorrhagic shock. Enteral feeding has been proposed as an adjunct for preserving mucosal integrity and decreasing translocation-related morbidities during stress. The purpose of this study was to determine if an ileal mucosal suffusion with an isotonic glucose or glutamine solution begun after resuscitation would prevent development of this blood flow impairment. The distal ileum of anesthetized Sprague-Dawley rats was prepared for in vivo videomicroscopy. Animals were bled to 50% of baseline blood pressure for 60 min and then resuscitated with their shed blood and an equal volume of lactated Ringers. After resuscitation was complete, the mucosa was suffused with isotonic glucose, glutamine, or saline (control). Resuscitation restored cardiac output and mean arterial pressure to baseline in all groups; however, first-order arteriolar blood flow remained 50% below baseline in the saline group. Glucose-treated animals demonstrated a 34% increase over baseline in first-order arteriolar blood flow 120 min after resuscitation due to submucosal and previllus arteriolar dilation. This effect became evident 30 min after initiating the suffusion, suggesting an effect mediated via locally generated vasodilators. Glutamine suffusion attenuated the flow impairment by dilation of previllus arterioles but to a lesser degree than that observed in glucose-treated animals. These data demonstrate that mucosal suffusion with an isotonic glucose solution overrides the residual effects of hemorrhagic shock on the intestinal microcirculation and suggest a mechanism for preserving mucosal integrity with the addition of glutamine to standard enteral formulations.

Mechanisms of malignant ascites production

The accumulation of malignant ascites is determined primarily by the obstruction of diaphragmatic lymphatics with tumor inhibiting the outflow of peritoneal fluid. An abnormal increase in peritoneal fluid production has been shown to contribute to ascites formation by a marked neovascularization of the parietal peritoneum. Cell-free malignant ascitic fluid obtained from rats with intra-abdominal Walker 256 carcinoma when infused into the peritoneal cavities of normal animals causes an increase in edema formation and an increase in the permeability of protein from normal omental vessels. Protamine sulfate, a known inhibitor of angiogenesis when infused into the peritoneal cavity along with cell free malignant ascitic fluid, significantly reduces the leak of protein from the intravascular space when compared to ascites alone. Persistent permeability changes continue to exist even after the inhibition of vessel proliferation. These results indicate that angiogenesis is responsible for a major portion of the increase in permeability caused by malignant ascitic fluids. Other tumor-induced factors may be present which alter vascular permeability by other mechanisms which remain to be elucidated.

Pedal or peroneal bypass: Which is better when both are patent?

PURPOSE We compared autogenous vein pedal and peroneal bypasses, focusing on extremities that could have a bypass to either artery. METHODS From 1985 to 1993 we performed a total of 175 pedal and 77 peroneal autogenous vein bypasses for rest pain (n = 75, 30%) and tissue loss (n = 177, 70%). One hundred ninety-six (78%) in situ saphenous vein and 56 (22%) reversed or composite vein bypasses were performed. One hundred fifty-two of these 252 bypasses were performed in extremities with both the pedal and peroneal arteries patent by arteriography. The vascular surgeon chose to perform 99 pedal and 53 peroneal vein bypasses in these 152 extremities. RESULTS The angiogram score of the outflow arteries were similar for pedal and peroneal bypasses with the Society for Vascular Surgery and the International Society for Cardiovascular Surgery and modified scoring systems. At 2 years the primary and secondary patency rates for pedal bypasses (70% and 77%) were not significantly different compared with those for peroneal bypasses (60% and 72%). Limb salvage rates at 2 years were similar for pedal and peroneal bypasses for all patients (74% and 73%), patients with both pedal and peroneal arteries patent (83% and 72%), diabetics (76% and 66%), and patients with tissue necrosis (77% and 71%). CONCLUSIONS Pedal and peroneal artery bypasses with equivalent angiogram scores have similar long-term graft patency and limb salvage. The choice between pedal or peroneal artery bypass should be based on the quality of vein and the surgeons preference.

Pentoxifylline but not saralasin restores hepatic blood flow after resuscitation from hemorrhagic shock

After determining that hepatic blood flow remains impaired after resuscitation from hemorrhagic shock, we used the angiotensin II receptor antagonist saralasin and pentoxifylline to investigate their respective effects on hepatic blood flow responses after resuscitation from hemorrhagic shock. Rats were bled to 50% of baseline blood pressure for 60 min and resuscitated with shed blood and an equal volume of lactated Ringers solution. Saralasin [10 micrograms/kg per min (n = 6)], pentoxifylline [25 mg/kg bolus and 12.5 mg/kg per hr (n = 7)], or saline (n = 11) were started with the onset of resuscitation. Total hepatic blood flow measured by ultrasonic transit time flow meter, effective nutrient hepatic blood flow measured by galactose clearance, mean arterial pressure, and cardiac output were recorded at 15-min intervals for 2 hr after resuscitation. Hemorrhage decreased cardiac output 57% below baseline and decreased total hepatic blood flow 64% below baseline. Resuscitation restored cardiac output to baseline levels in all three groups. Despite restoration of cardiac output, total hepatic and effective hepatic blood flow remained significantly below baseline in the saline control and saralasin groups but was restored to baseline levels in the pentoxifylline group. These data indicate that angiotensin II does not contribute significantly to the hepatic blood flow impairment after resuscitation from hemorrhagic shock. Improvement in flow with pentoxifylline implies that hemorrhage and resuscitation impair hepatic microvascular hemorrheology and that addition of pentoxifylline to standard resuscitation corrects the impairment.

Resuscitation regimens for hemorrhagic shock must contain blood.

Endothelial cell dysfunction occurs during hemorrhagic shock (HS) and persists despite adequate resuscitation (RES) that restores and maintains hemodynamics. We hypothesize that RES from HS with crystalloid solutions alone aggravate the endothelial cell dysfunction. To test this hypothesis, anesthetized nonheparinized rats were monitored for hemodynamics, and the terminal ileum was studied with intravital video microscopy. HS was 50% of mean arterial pressure (MAP) for 60 min. Four hemorrhaged groups (10 animals in each group) were randomized for RES: group I with shed blood returned + equal volume of normal saline (NS); group II with shed blood returned + 2× NS; group III with 2× NS only; and group IV with 4× NS only. Two hours post-RES, endothelial cell function was assessed with the endothelial-dependent agonist acetylcholine (ACh, 10−9–10−4 M). Maximum arteriolar diameter was elicited by the endothelial-independent agonist sodium nitroprusside (NTP, 10−4 M). HS caused a selective vasoconstriction associated with low blood flow in inflow A1 arterioles in all hemorrhaged groups. Post-RES vasoconstriction developed in A1 and premucosal arterioles (pA3 and dA3) in all hemorrhaged groups regardless of the RES regimen. However, A1 vasoconstriction and flow were significantly worst in the animals RES with NS alone (−43% and −75%, respectively) compared with those resuscitated with blood and NS (−27% and −57%). Impaired dilation response to ACh was noted in all hemorrhaged animals. However, a significant shift to the right of the dose-response curve (decreased sensitivity) was observed in the animals resuscitated with NS alone irrespective of the RES volume. These animals required at least two orders of magnitude greater ACh concentration to produce a 20% dilation response. For all vessel types, Group II had the best preservation of endothelial cell function. In conclusion, HS causes a selective vasoconstriction of A1 arterioles, which was not observed in A3 vessels. RES from HS results in progressive vasoconstriction in all intestinal arterioles irrespective of the RES regimen. Crystalloid RES after HS does not restore hemodynamics to baseline and is associated with a marked endothelial cell dysfunction. Blood-containing RES regimens preserve and maintain hemodynamics and are associated with the least microvascular dysfunction. Therefore, regimens for RES from HS must contain blood. Endothelial cell dysfunction is not the sole etiologic factor of post-RES microvascular impairment.

Practicing surgeons lead in quality care, safety, and cost control.

Objective:To report the experiences of 66 surgical specialists from 15 different hospitals who performed 43 CPT-based procedures more than 16,000 times. Summary Background Data:Surgeons are under increasing pressure to demonstrate patient safety data as quantitated by objective and subjective outcomes that meet or exceed the standards of benchmark institutions or databases. Methods:Data from 66 surgical specialists on 43 CPT-based procedures were accessioned over a 4-year period. The hospitals vary from a small 30-bed hospital to large teaching hospitals. All reported deaths and complications were verified from hospital and office records and compared with benchmarks. Results:Over a 4-year inclusive period (1999–2002), 16,028 elective operations were accessioned. There was a total 1.4% complication rate and 0.05% death rate. A system has been developed for tracking outcomes. A wide range of improvements have been identified. These include the following: 1) improved classification of indications for systemic prophylactic antibiotic use and reduction in the variety of drugs used, 2) shortened length of stay for standard procedures in different surgical specialties, 3) adherence to strict indicators for selected operative procedures, 4) less use of costly diagnostic procedures, 5) decreased use of expensive home health services, 6) decreased use of very expensive drugs, 7) identification of the unnecessary expense of disposable laparoscopic devices, 8) development of a method to compare a one-surgeon hospital with his peers, and 9) development of unique protocols for interaction of anesthesia and surgery. The system also provides a very good basis for confirmation of patient safety and improvement therein. Conclusions:Since 1998, Quality Surgical Solutions, PLLC, has developed simple physician-authored protocols for delivering high-quality and cost-effective surgery that measure up to benchmark institutions. We have discovered wide areas for improvements in surgery by adherence to simple protocols, minimizing death and complications and clarifying cost issues.

Intraperitoneal Resuscitation Improves Intestinal Blood Flow Following Hemorrhagic Shock

ObjectiveTo study the effects of peritoneal resuscitation from hemorrhagic shock. Summary Background DataMethods for conventional resuscitation (CR) from hemorrhagic shock (HS) often fail to restore adequate intestinal blood flow, and intestinal ischemia has been implicated in the activation of the inflammatory response. There is clinical evidence that intestinal hypoperfusion is a major factor in progressive organ failure following HS. This study presents a novel technique of peritoneal resuscitation (PR) that improves visceral perfusion. MethodsMale Sprague-Dawley rats were bled to 50% of baseline mean arterial pressure (MAP) and resuscitated with shed blood plus 2 equal volumes of saline (CR). Groups were 1) sham, 2) HS + CR, and 3) HS + CR + PR with a hyperosmolar dextrose-based solution (Delflex 2.5%). Groups 1 and 2 had normal saline PR. In vivo videomicroscopy and Doppler velocimetry were used to assess terminal ileal microvascular blood flow. Endothelial cell function was assessed by the endothelium-dependent vasodilator acetylcholine. ResultsDespite restored heart rate and MAP to baseline values, CR animals developed a progressive intestinal vasoconstriction and tissue hypoperfusion compared to baseline flow. PR induced an immediate and sustained vasodilation compared to baseline and a marked increase in average intestinal blood flow during the entire 2-hour post-resuscitation period. Endothelial-dependent dilator function was preserved with PR. ConclusionsDespite the restoration of MAP with blood and saline infusions, progressive vasoconstriction and compromised intestinal blood flow occurs following HS/CR. Hyperosmolar PR during CR maintains intestinal blood flow and endothelial function. This is thought to be a direct effect of hyperosmolar solutions on the visceral microvessels. The addition of PR to a CR protocol prevents the splanchnic ischemia that initiates systemic inflammation.

Direct Peritoneal Resuscitation Accelerates Primary Abdominal Wall Closure after Damage Control Surgery

BACKGROUND Damage control surgery is a staged approach to the trauma patient in extremis that improves survival, but leads to open abdominal wounds that are difficult to manage. We evaluated whether directed peritoneal resuscitation (DPR) when used as a resuscitation strategy in severely injured trauma patients with hemorrhagic shock requiring damage control surgery would affect the amount of and timing of resuscitation and/or show benefits in time to abdominal closure and reduction of intra-abdominal complications. STUDY DESIGN A retrospective case-matched study of patients undergoing damage control surgery for hemorrhagic shock secondary to trauma between January 2005 and December 2008 was performed. Twenty patients undergoing standardized wound closure and adjunctive DPR were identified and matched to 40 controls by Injury Severity Score, age, gender, and mechanism of injury. A single early death was excluded because of inability to control ongoing hemorrhage. RESULTS There were no differences in age, gender, or mechanism of injury between the groups. Injury Severity Score (35.07 +/- 17.1 versus DPR 34.95 +/- 16.95; p = 0.82) and packed red blood cell administration in 24 hours (23.8 +/- 14.35 U versus DPR 26.9 +/- 14.1 U; p = 0.43) were similar between the groups. Presenting pH was similar between the study group and the DPR group (7.24 +/- 0.13 d versus DPR 7.26 +/- 0.11; p = 0.8). Time to definitive abdominal closure was significantly less in the DPR group compared with controls (DPR: 4.35 +/- 1.6 d versus 7.05 +/- 3.31; p < 0.003). DPR also allowed for a higher rate of primary fascial closure, lower intra-abdominal complication rate, and lower rate of ventral hernia formation at 6 months. Adjunctive DPR afforded a definitive wound closure advantage compared with Wittmann patch closure techniques (DPR 4.35 +/- 1.6 versus Wittmann patch 6.375 +/- 1.3; p = 0.004). CONCLUSIONS The addition of adjunctive DPR to the damage control strategy shortens the interval to definitive fascial closure without affecting overall resuscitation volumes. As a result, this mitigates intra-abdominal complications associated with open abdomen and damage control surgery and affords better patient outcomes.

Diagnostic Transdiaphragmatic Pericardiotomy in Thoracoabdominal Trauma

Sixty patients with combined thoracoabdominal trauma underwent diagnostic transdiaphragmatic pericardiotomy to assess possible cardiac injury. Injuries were from penetration in 53 patients and from blunt trauma in seven. Transdiaphragmatic pericardiotomy was positive in 19 patients with 17 subsequently having documented cardiac injury. This technique is a safe and rapid method of evaluation for patients with combined thoracoabdominal injury who have an injury in proximity to the heart, or unexplained hypotension occurring during an abdominal exploratory operation.