Graciela Martínez-Pallí

Gas exchange mechanism of orthodeoxia in hepatopulmonary syndrome

The mechanism of orthodeoxia (OD), or decreased partial pressure of arterial oxygen (PaO2) from supine to upright, a characteristic feature of hepatopulmonary syndrome (HPS), has never been comprehensively elucidated. We therefore investigated the intrapulmonary (shunt and ventilation‐perfusion [V̇A/Q̇] mismatching) and extrapulmonary factors governing PaO2 in 20 patients with mild to severe HPS (14 males, 6 females; 50 ± 3 years old SE) at upright and supine, in random order. We set out a cutoff value for OD, namely a PaO2 decrease ≥5% or ≥4 mm Hg (area under the receiver operating characteristic curve, 0.96 each). Compared to supine, 5 patients showed OD (PaO2 change, −11% ± 2%, −7 ± 1 mm Hg, P < .05) with further V̇A/Q̇ worsening (shunt + low V̇A/Q̇ mode increased from 19% ± 7% to 21% ± 7% of cardiac output [Q̇T], P < .05), as opposed to 15 patients who did not (+2% ± 2%, +1± 1 mm Hg) with V̇A/Q̇ improvement (from 20% ± 4% to 16% ± 4% of Q̇T, P < .01). Cardiac output was significantly lower in OD patients in both positions. Changes in extrapulmonary factors at upright, such as increased minute ventilation and decreased Q̇T, were of similar magnitude in both subsets of patients. In conclusion, our data suggest that gas exchange response to OD in HPS points to a more altered pulmonary vascular tone inducing heterogeneous blood flow redistribution to lung zones with prominent intrapulmonary vascular dilatations. (HEPATOLOGY 2004;40:660–666.)

Severe Complications Limit Long-Term Clinical Success of Self-Expanding Metal Stents in Patients With Obstructive Colorectal Cancer

OBJECTIVES:Self-expanding metal stents (SEMS) are increasingly being used to treat malignant colorectal obstruction. However, complications have been reported in up to 50% of patients. There is limited information on long-term outcomes of these patients. The aim of this study was to retrospectively assess the long-term clinical success of SEMS in patients with malignant colorectal obstruction in a single tertiary center and to identify possible predictive factors of developing complications.METHODS:A total of 47 attempts to insert colorectal SEMS were made in 47 patients during a 5-year period. Stents of 9-cm length were placed under endoscopic and radiologic monitoring. After 24 h, all patients underwent abdominal X-ray to verify correct positioning of the stent. Patients were followed at the outpatient clinic.RESULTS:Insertion success was achieved in 44 (94%) patients. Acceptable initial colonic decompression was observed in 44 out of 47 (94%) attempts and in all (100%) successfully inserted stents. The stents were placed in the rectum (n=7, 15%), sigmoid (n=33, 70%), left colon (n=4, 9%), or anastomosis (n=3, 6%). The majority of patients had stage IV disease (n=40, 85%). SEMS served as a bridge to scheduled surgery in 9 (20%) patients and as a palliative definitive treatment in 38 (80%) cases. Three patients were lost to follow-up, so the outcome was evaluated in 41 patients. Long-term clinical failure occurred in 21 (51%) patients and was due to complications such as: migration (n=9, 22%), obstruction (n=7, 17%), perforation (n=3, 7%), and tenesmus (n=2, 5%). Perforations occurred 3, 4, and 34 days after insertion, and all patients died. In the bridge-to-surgery group, primary anastomosis was possible in only four of nine patients (44%). Clinical failure was not associated with any tumor-related factor. However, eight of nine patients with stent migration and two of three patients with perforation had been previously treated with chemotherapy.CONCLUSIONS:Placement of SEMS does not seem to be as effective as suggested because of late complications. For patients with potentially curable lesions, the use of colonic stents for malignant obstruction should only be considered when surgery is scheduled shortly after the stent insertion. Moreover, in patients with incurable obstructing colorectal cancer eligible for chemotherapy and a long life expectancy, palliative treatments other than SEMS should be considered.

Endoscopic ultrasound-guided fine-needle aspiration and trucut biopsy in the diagnosis of gastric stromal tumors: a randomized crossover study.

BACKGROUND AND AIM The diagnosis of gastrointestinal stromal tumors (GISTs) has important prognostic and therapeutic implications. The specific diagnosis of GIST has to be based on immunocytochemistry. This study aimed to prospectively compare in a crossover manner the accuracy of endoscopic ultrasound (EUS)-guided fine-needle aspiration (EUS-FNA) and EUS-guided trucut biopsy (EUS-TCB) in the specific diagnosis of gastric GISTs. We hypothesized that EUS-TCB is superior to EUS-FNA in this respect. PATIENTS AND METHODS Forty patients with gastric subepithelial tumors suspected on the basis of EUS of being a GIST underwent both EUS-FNA and EUS-TCB. The sequence in which the techniques were employed was randomly assigned to avoid bias. RESULTS Forty tumors were sampled (mean number of passes: 2.1 +/- 0.9 with EUS-TNB and 1.9 +/- 0.8 with EUS-FNA; P = not significant, NS). Final diagnoses were: GIST (n = 27), carcinoma (n = 2), leiomyoma (n = 1), schwannoma (n = 1), and no diagnosis possible (n = 9). Device failure occurred in 6 patients with EUS-TCB. A cytohistological diagnosis of mesenchymal tumor (n = 29) and carcinoma (n = 2) was made in 70 % of cases by EUS-FNA and in 60 % of cases by EUS-TCB ( P = NS). Among the samples that were adequate, immunohistochemistry could be performed in 74 % of EUS-FNA samples and in 91 % of EUS-TCB samples ( P = 0.025). When inadequate samples were included, the overall diagnostic accuracy of EUS-FNA was 52 % and that of EUS-TCB was 55 % ( P = NS). There were no complications. CONCLUSIONS EUS-TCB is not superior to EUS-FNA in GISTs because of the high rate of technical failure of trucut. However, when an adequate sample is obtained with EUS-TCB, immunohistochemical phenotyping is almost always possible. EUS-TCB can be safely performed in this set of patients.

An assessment of thromboelastometry to monitor blood coagulation and guide transfusion support in liver transplantation

BACKGROUND: Rotation thromboelastometry (TEM) has been proposed as a convenient alternative to standard coagulation tests in guiding the treatment of coagulopathy during orthotopic liver transplantation (OLT). This study was aimed at assessing the value of TEM in monitoring blood coagulation and guide transfusion support in OLT.

Severe portopulmonary hypertension after liver transplantation in a patient with preexisting hepatopulmonary syndrome.

BACKGROUND Portopulmonary hypertension and hepatopulmonary syndrome have been considered mutually exclusive pulmonary vascular disorders in liver disease states. METHODS This current report describes a middle-aged patient, a candidate for liver transplantation, diagnosed with hepatopulmonary syndrome on the basis of clinical, echocardiographic and gas exchange criteria. Unusually high pulmonary pressures were observed at liver transplantation, performed 6 months after the initial diagnosis of hepatopulmonary syndrome. Three months later, the patient developed severe pulmonary hypertension and died of right ventricular failure during a second attempted liver transplantation. Postmortem histologic findings in the lung confirmed the presence of plexogenic pulmonary arteriopathy. CONCLUSION This case illustrates the potential occurrence of hepatopulmonary syndrome and portopulmonary hypertension in the same patient, suggesting that the presence of hepatopulmonary syndrome may not preclude the development of portopulmonary hypertension.

Effects of carbon dioxide vs helium pneumoperitoneum on hepatic blood flow

AbstractBackground: Elevated intraabdominal pressure due to gas insufflation for laparoscopic surgery may result in regional blood flow changes. Impairments of hepatic, splanchnic, and renal blood flow during peritoneal insufflation have been reported. Therefore we set out to investigate the effects of peritoneal insufflation with helium (He) and carbon dioxide (CO2) on hepatic blood flow in a porcine model. Methods: Twelve pigs were anesthetized and mechanically ventilated with a fixed tidal volume after the stabilization period. Peritoneal cavity was insufflated with CO2 (n= 6) or He (n= 6) to a maximum intraabdominal pressure of 15 mmHg. Hemodynamic parameters, gas exchange, and oxygen content were studied at baseline, 90 mm and 150 min after pneumoperitoneum, and 30 min after desufflation. Determination of hepatic blood flow with indocyanine green was made at all measured points by a one-compartment method using hepatic vein catheterization. Results: A similar decrease in cardiac output was observed during insufflation with both gases. Hepatic vein oxygen content decreased with respect to the baseline during He pneumoperitoneum (p < 0.05), but it did not change during CO2 insufflation. Hepatic blood flow was significantly reduced in both the He and CO2 pneumoperitoneums at 90 min following insufflation (63% and 24% decrease with respect to the baseline; p < 0.001 and p < 0.05, respectively) being this decrease marker in the He group (p= 0.02). Conclusions: These findings suggest that helium intraperitoneal insufflation results in a greater impairment on hepatic blood flow than CO2 insufflation.

Personalised Prehabilitation in High-risk Patients Undergoing Elective Major Abdominal Surgery: A Randomized Blinded Controlled Trial

Objective: The aim of this study was to assess the impact of personalized prehabilitation on postoperative complications in high-risk patients undergoing elective major abdominal surgery. Summary Background Data: Prehabilitation, including endurance exercise training and promotion of physical activity, in patients undergoing major abdominal surgery has been postulated as an effective preventive intervention to reduce postoperative complications. However, the existing studies provide controversial results and show a clear bias toward low-risk patients. Methods: This was a randomized blinded controlled trial. Eligible candidates accepting to participate were blindly randomized (1:1 ratio) to control (standard care) or intervention (standard care + prehabilitation) groups. Inclusion criteria were: i) age >70 years; and/or, ii) American Society of Anesthesiologists score III/IV. Prehabilitation covered 3 actions: i) motivational interview; ii) high-intensity endurance training; and promotion of physical activity. The main study outcome was the proportion of patients suffering postoperative complications. Secondary outcomes included the endurance time (ET) during cycle-ergometer exercise. Results: We randomized 71 patients to the control arm and 73 to intervention. After excluding 19 patients because of changes in the surgical plan, 63 controls and 62 intervention patients were included in the intention-to-treat analysis. The intervention group enhanced aerobic capacity [&Dgr;ET 135 (218) %; P < 0.001), reduced the number of patients with postoperative complications by 51% (relative risk 0.5; 95% confidence interval, 0.3–0.8; P = 0.001) and the rate of complications [1.4 (1.6) and 0.5 (1.0) (P =  0.001)] as compared with controls. Conclusion: Prehabilitation enhanced postoperative clinical outcomes in high-risk candidates for elective major abdominal surgery, which can be explained by the increased aerobic capacity.

Endoscopic ultrasonography in patients with large gastric folds at endoscopy and biopsies negative for malignancy : Predictors of malignant disease and clinical impact

OBJECTIVES:The aims of the study were to assess in patients with large gastric folds at endoscopy and endoscopic biopsies that tested negative for malignancy: (i) the predictive variables of malignancy in endoscopic ultrasonography (EUS), (ii) the impact of EUS.METHODS:Patients with this condition evaluated with radial EUS (following the standard study protocol of our Unit in these patients) during a 5-yr period were included. Nine variables were evaluated as possible predictors of malignancy (χ2, t-test, and logistic regression procedure) using pathology results, or a minimum of 2 yr of follow-up as gold standard. Likelihood ratios (LR), pre-EUS, and post-EUS probabilities for the diagnosis of malignancy were used to assess the clinical impact of the technique.RESULTS:Sixty-one patients were included (40 benign and 21 malignant). Predictive factors of malignancy were as follows: thickened gastric wall, thickened deep layers, impaired gastric distension, loss of the wall structure, and presence of ascites or lymph nodes, whereas the enlargement of superficial layers was a predictor of a benign condition. The enlargement of deep layers, as assessed by EUS was the only independent predictive factor for malignancy. When using this parameter, the pre-EUS probability of malignancy in our series (34%) increased up to 95% when EUS suggested malignancy (positive LR = 45), whereas it decreased to 4.7% when EUS precluded this diagnosis (negative LR = 0.102).CONCLUSIONS:(i) The enlargement of deep layers is the only independent predictive factor for malignancy in patients with large gastric folds at endoscopy and biopsies testing negative for malignancy and (ii) EUS has a high clinical impact in these patients.

Yes, we can: reliable colonic closure with the Padlock-G clip in a survival porcine study (with video).

BACKGROUND Secure closure of the colonic access site is one of the most important issues for the development of natural orifice transluminal endoscopic surgery. OBJECTIVE To evaluate the feasibility, reproducibility, and efficacy of a new over-the-scope clip. DESIGN Descriptive study, in vivo porcine colon. INTERVENTION In 10 female Yorkshire pigs weighing 30 to 35 kg, a 10-mm colotomy was performed by using a needle-knife and advancing the endoscope to the peritoneal cavity. Colonic closure was performed by using the Padlock-G clip (Aponos Medical, Kingston, NH) delivered with the Lock-It system (Aponos). MAIN OUTCOME MEASUREMENTS Animals were monitored daily for signs of peritonitis and sepsis over a period of 14 days. During necropsy, the peritoneal cavity was examined, and the colon segment containing the incision was excised for pathological study. RESULTS Closure was achieved in all cases. Nine of 10 pigs survived 14 days without complications, but 1 pig was killed immediately after the procedure because of severe bleeding during the colonic incision. The median closure time was 8 minutes (range 1-30 minutes). At necropsy, adhesions were observed in 5 cases. The incision was hardly visible at the serosa side in 3 cases and was not identified in 6 cases. In 6 cases, the clip was still slightly attached to the mucosa, and it was not found in 3 cases. The pathological study revealed a complete remodeling of the colonic wall in all cases. LIMITATIONS Animal model, noncomparative study. CONCLUSION The Padlock-G clip procedure is feasible, reproducible, effective, and easy to perform, and it provides a reliable colonic closure.

Impact of deep sedation on the accuracy of hepatic and portal venous pressure measurements in patients with cirrhosis.

Measurement of the hepatic venous pressure gradient (HVPG) offers valuable prognostic information in patients with cirrhosis. In specific circumstances, (children, agitated patients, TIPS placement) deep sedation is required. This study aims to assess the impact of deep sedation on the accuracy of hepatic/portal pressure measurements.