Wisam Khoury

Inhaled nitric oxide improves pulmonary functions following massive pulmonary embolism: a report of four patients and review of the literature.

Acute pulmonary embolism increases pulmonary vascular resistance and may lead to acute right ventricular failure and cardiocirculatory collapse and respiratory failure, possibly resulting in substantial morbidity and mortality. Inhaled nitric oxide (NO) dilates pulmonary blood vessels and has been used to reduce pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension and acute respiratory distress syndrome. This case series describes our experience with inhaled NO administered to four patients suffering from acute massive pulmonary embolism following abdominal surgery. The four described patients recovering from small bowel resection, pancreatoduodenectomy, hemipelvectomy, or recent gastrointestinal bleeding had severe respiratory and hemodynamic deterioration due to pulmonary embolism. Each received inhaled NO (20–25 ppm) via the inspiratory side of the breathing circuit of the ventilator. Pulmonary and systemic blood pressures, heart rate, and lung gas exchange improved in all the patients within minutes after the initiation of NO administration. Inhaled NO may be useful in treating acute massive pulmonary embolism. This potential application warrants further investigation.

Mannitol Attenuates Kidney Damage Induced by Xanthine Oxidase-Associated Pancreas Ischemia-Reperfusion

BACKGROUND Ischemia and subsequent reperfusion (IR) may induce local and remote organ reperfusion injury. It may be propagated by xanthine oxidase (XO)-generated oxidant stress. We investigated whether pancreas IR directly and acutely induces renal dysfunction and if this outcome could be prevented by mannitol. MATERIALS AND METHODS Rat pancreases were isolated and perfused with Krebs-Henseleit solution enriched with 5% bovine albumin. Other rats donated kidneys that were perfused at constant pressure mode. Each pancreas underwent 45 min of either perfusion (control) or ischemia (no flow). Both organ perfusion systems were then combined and the kidneys were perfused with the pancreatic 15-min reperfusate for 2 h. A third group consisted of paired ischemic pancreases and nonischemic kidneys treated with mannitol 250 mg/kg body weight during reperfusion. RESULTS The controls demonstrated no abnormal perfusion or metabolite changes. Pancreas and renal perfusion pressures increased by >50% in the ischemia group immediately upon reperfusion; it remained above the values of controls during the 2-h kidney reperfusion. Conversely, perfusion pressure in the treatment group was not significantly different from the control. The reduced glutathione level increased significantly, as did XO, immediately upon starting reperfusion in both organs appertaining to the ischemic group; this misbalance was not documented in the controls and the mannitol-treated groups. Urine output was severely reduced in the IR kidneys. CONCLUSION Ischemia/reperfusion of the rat pancreas evokes immediate renal dysfunction. Kidney oxidant-antioxidant balance is disturbed, but can be prevented with mannitol. These two figures underline the role of oxidative stress in promoting acute renal damage in the presence of pancreas IR.

Renal Apoptosis Following Carbon Dioxide Pneumoperitoneum in a Rat Model

PURPOSE Laparoscopically recruited kidneys regain normal function more slowly than laparotomy harvested organs for several possible reasons. We investigated the effects of CO(2) induced pneumoperitoneum on kidney function, as reflected by blood and urine creatinine levels, and its relation with renal cell apoptosis. MATERIALS AND METHODS CO(2) pneumoperitoneum was established in anesthetized Wistar male rats that were randomly allocated at 6 per group into 1 of 6 groups with an intraperitoneal pressure of 0 (control), 5, 8, 12, 15 or 18 mm Hg. Pressure was maintained for 60 minutes in all groups. Three additional groups were subjected to 30-minute pneumoperitoneum at 0, 12 and 18 mm Hg, respectively. The rats were kept alive for the ensuing 24 hours, after which blood and urine creatinine were analyzed and the abdominal organs were harvested. Various areas of the organs were analyzed for apoptotic cells using the TUNEL method. Cells were randomly counted in 10 eyeshots in 3 sections each using an ocular micrometer. RESULTS Creatinine levels in blood and urine changed as pressure and pneumoperitoneum duration progressed. Isolated TUNEL positive nuclei were detected in the outer medulla and the cortex of control kidneys. There was a significantly higher number of TUNEL positive nuclei in the cortex and the medulla of all pressurized kidneys (p <0.05), which increased in parallel with increasing intraperitoneal pressure and pneumoperitoneum exposure time. CONCLUSIONS The CO(2) pneumoperitoneum gradient and its duration affect renal function and induce apoptosis. This could be a mechanism involved in renal delayed graft dysfunction in recipients of laparoscopically harvested kidneys.

Transanal Endoscopic Microsurgery for the Resection of Submucosal and Retrorectal Tumors

Background: Transanal endoscopic microsurgery (TEM) was originally designed for local endoscopic excision of benign and low-grade mucosal rectal lesions through an endoscopic system. The procedure is particularly challenging for submucosal and retrorectal lesions, as the tumor margins are not well defined. Objective: To investigate patient and surgical characteristics of TEM as a treatment for submucosal rectal and retrorectal lesions. Methods: All the patients in our department of general surgery who underwent TEM for a submucosal rectal or retrorectal lesion, between the years 2001 and 2011, were identified. Their charts were reviewed and data pertaining to demographic characteristics and medical history, including tumor characteristics, were collected. Operative notes and histopathology reports were also reviewed. The adequacy of the tumor resection, that ism attainment of free margins, endoscopic completion of the procedure, and perioperative complications, were assessed. Results: Fifteen patients (5 females, 10 males), mean age 53.9±16.9 years, were identified. The main indications for surgery were gastrointestinal stromal tumor (5 patients) and tailgut or duplication cyst (4 patients). All procedures were completed endoscopically. The median distance from the anal verge was 7.3 cm (range, 5 to 10 cm), and the mean diameter of the tumors was 3±1.1 cm. The one patient in whom the margins presented tumoral involvement underwent repeated TEM. No intraoperative complications were reported. The postoperative complication rate was 13.3%, and the mean length of hospital stay was 1.85±1.77 days. Conclusions: TEM for retrorectal and submucosal rectal lesions is feasible and safe. A remarkably low morbidity rate and limited surgical injury favor TEM in selected patients.

The hemodynamic effects of CO2-induced pressure on the kidney in an isolated perfused rat kidney model.

Background Variable mechanisms were suggested to mediate the changes in renal hemodynamics during pneumoperitoneum. To assess whether it can be pressure dependent only, we conduct a study in an isolated, pressurized, and perfused organ model. Methods Seventy Wistar rat kidneys were perfused with oxygenated, 3% albumin-contained Krebs-Henseleit solution. Experiments took place within Plexiglass chamber that provided conditions for perfusion of organs, humidity, and maintenance of intracameral CO2 pressures [0 (control), 3, 5, 8, 12, 15, and 18 mm Hg]. All kidneys (10/group) were perfused for 60 minutes. One-half of the groups were perfused for an additional 30 minutes, during which the perfusion pressures were reduced to 0 mm Hg. pH of the perfusate was measured as well. Results The perfusion pressure increased and the kidney flow decreased slightly, in proportion with the intrachamber pressure. Urine output decreased to a minimum of 40% in ≥8 mm Hg pressure conditions, compared with the control group. The pH values were below normal, during experimental pneumoperitoneum. Conclusions Pneumoperitoneal conditions are a direct cause of changes in renal urinary output. The increase in pCO2 pressure and consequently low intraorgan pH may contribute to a mild transient renal damage during pneumoperitoneum.

Repeated transanal endoscopic microsurgery is feasible and safe.

BACKGROUND The benefits of transanal endoscopic microsurgery (TEM) for the excision of benign and low-grade malignant lesions in the low and middle rectum are well recognized. This study examined the feasibility and safety of a repeated TEM procedure. PATIENTS AND METHODS Patients who underwent a repeat TEM for excision of rectal lesions, either for involved resection margins or for local recurrence, between the years 2000 and 2010, were identified. Rectal lesion characteristics were retrieved. Mean operative times, length of hospital stay, and intra- and postoperative complications were compared between primary and repeated procedures. The postoperative histopathology reports were reviewed, and the adequacy of resection was determined. All patients completed a questionnaire based on the Wexner score for anal sphincter function evaluation. RESULTS Fourteen patients (3 female, 11 male) underwent a repeat TEM operation during the study period. All procedures were completed endoscopically. Indications for repeated TEM were involved margins in 12 patients and recurrence of benign tumor in 2. Mean operative time, mean length of hospital stay, and rate of postoperative complications were similar for primary and repeated TEM procedures (62.5 ± 17 versus 55 ± 23 minutes, P=.181; 1.7 ± 1.3 versus 1.7 ± 1.12 days, P=.99; and 35.7% versus 21.4%, P=.66, respectively). The Wexner score was comparable at baseline and after the first and the second TEM procedures (1.5 ± 2.3, 1.5 ± 2.3, and 3.3 ± 3.1, respectively; P=.188). No cases of fecal incontinence following a repeat TEM were documented. CONCLUSIONS Repeated TEM is feasible and safe and may be appropriate for selected patients.

Transanal Endoscopic Microsurgery: Current and Future Perspectives.

Transanal endoscopic microsurgery is part of the colorectal surgeons’ armamentarium for over 2 decades. Since its first implementation for the resection of benign and T1 malignant lesions in the rectum several new indications were developed and it carries additional promise for further extension in upcoming years. Herein we review the technique, its current indications, novel implications, and future perspectives.

Assessment of the clinical usefulness of imaging modalities in identifying postoperative upper gastrointestinal tract leaks requiring reoperation.

Purpose: To assess the usefulness of imaging modalities in the diagnosis and determination of whether postoperative upper gastrointestinal tract leak (UGITL) requires operative intervention. Methods: Patients with suspected UGITL who underwent reoperation ⩽30 days after the primary operation with intraoperative confirmation of leaks were identified. Data of those patients who had undergone computerized tomography (CT) or upper gastrointestinal contrast study (UGIS) before reoperation were reviewed. The usefulness and impact of imaging studies obtained before reoperation were evaluated. Results: Thirty patients with confirmed UGITL were identified, 24 of whom had undergone imaging studies before reoperation. Fourteen CTs (63.7%) and 4 UGIS (67%) were positive or highly indicative of UGITL. The interval between the primary operation and the reoperation and the morbidity rates after the reoperation were similar between patients with and those without imaging studies before the reoperation (5.6±4.8 vs. 6.8±4.2 d, P=0.55; 91.6% vs. 100%, P=0.29, respectively). False-negative imaging results caused postponement of reoperation by ≥24 hours in 4 patients whose outcome was similar to those with true-positive results. Conclusions: CTs and UGIS are supportive tools when deciding whether to reoperate for postoperative UGITL. However, a negative imaging study for UGITL does not exclude it definitively, and therefore should not replace clinical evaluations.