Lymph node characterization in vivo using endoscopic ultrasound spectrum analysis with electronic array echo endoscopes.

Our purpose was to demonstrate the use of radiofrequency spectral analysis to distinguish between benign and malignant lymph nodes with data obtained using electronic array echo endoscopes, as we have done previously using mechanical echo endoscopes. In a prospective study, images were obtained from eight patients with benign-appearing lymph nodes and 11 with malignant lymph nodes, as verified by fine-needle aspiration. Midband fit, slope, intercept, correlation coefficient, and root-mean-square (RMS) deviation from a linear regression of the calibrated power spectra were determined and compared between the groups. Significant differences were observable for mean midband fit, intercept, and RMS deviation (t test P < 0.05). For benign (n = 16) vs. malignant (n = 12) lymph nodes, midband fit and RMS deviation provided classification with 89 % accuracy and area under receiver operating characteristic (ROC) curve of 0.95 based on linear discriminant analysis. We concluded that the mean spectral parameters of the backscattered signals from electronic array echo endoscopy can provide a noninvasive method to quantitatively discriminate between benign and malignant lymph nodes.

Diaphragm pacing with natural orifice transluminal endoscopic surgery: potential for difficult-to-wean intensive care unit patients.

BACKGROUND: Up to 50% of the patients in the intensive care unit (ICU) require mechanical ventilation, with 20% requiring the use of a ventilator for more than 7 days. More than 40% of this time is spent weaning the patient from mechanical ventilation. Failure to wean from mechanical ventilation can in part be attributable to rapid onset of diaphragm atrophy, barotrauma, posterior lobe atelectasis, and impaired hemodynamics, which are normally improved by maintaining a more natural negative chest pressure. The authors have previously shown that laparoscopic implantation of a diaphragm pacing system benefits selected patients. They now propose that an acute ventilator assist with interventional neurostimulation of the diaphragm in the ICU is feasible and could facilitate the weaning of ICU patients from mechanical ventilation. Natural orifice transluminal endoscopic surgery (NOTES) has the potential to expand the benefits of the diaphragm pacing system to this acute patient population by allowing it to be performed at the bedside similarly to insertion of the common gastrostomy tube. This study evaluates the feasibility of this approach in a porcine model. METHODS: Pigs were anesthetized, and peritoneal access with the flexible endoscope was obtained using a guidewire, needle knife cautery, and balloon dilation. The diaphragm was mapped using a novel endoscopic electrostimulation catheter to locate the motor point (where stimulation provides complete contraction of the diaphragm). An intramuscular electrode then was placed at the motor point with a percutaneous needle. The gastrotomy was managed with a gastrostomy tube. RESULTS: Four pigs were studied, and the endoscopic mapping instrument was able to map the diaphragm to identify the motor point. In one animal, a percutaneous electrode was placed into the motor point under transgastric endoscopic visualization, and the diaphragm could be paced in conjunction with mechanical ventilation. CONCLUSIONS: These animal studies demonstrate the feasibility of transgastric mapping of the diaphragm and implantation of a percutaneous electrode for therapeutic diaphragmatic stimulation.

A reliable method for monitoring intraabdominal pressure during natural orifice translumenal endoscopic surgery.

BACKGROUND: Natural orifice translumenal endoscopic surgery (NOTES) provides surgical access to the peritoneal cavity without skin incisions. The NOTES procedure requires pneumoperitoneum for visualization and manipulation of abdominal organs, similar to laparoscopy. Accurate measurement of the pneumoperitoneum pressure is essential to avoid potentially deleterious effects of intraabdominal compartment syndrome. A reliable method for monitoring pneumoperitoneum pressures during NOTES has not been identified. This study evaluated several methods of monitoring intraabdominal pressures with a standard gastroscope during NOTES. METHODS: Four female pigs (25 kg) were sedated, and a single-channel gastroscope was passed transgastrically into the peritoneal cavity. Pneumoperitoneum was achieved via a pressure insufflator through a percutaneous, intraperitoneal 14-gauge catheter. Three other pressures were recorded via separate catheters. First, a 14-gauge percutaneous catheter passed intraperitoneally measured true intraabdominal pressure. Second, a 14-gauge tube attached to the endoscope was used to measure endoscope tip pressure. The third pressure transducer was connected directly to the accessory channel of the endoscope. The abdomen was insufflated to a range of pressures (10-30 mmHg), and simultaneous pressures were recorded from all three pressure sensors. RESULTS: Pressure correlation curves were developed for all animals across all intraperitoneal pressures (mean error, -4.25 to -1 mmHg). Endoscope tip pressures correlated with biopsy channel pressures (R2 = 0.99). Biopsy channel and endoscope tip pressures fit a least-squares linear model to predict actual intraabdominal pressure (R = 0.99 for both). Both scope tip and biopsy channel port pressures were strongly correlative with true intraabdominal pressures (R2 = 0.98 and R2 = 0.99, respectively). CONCLUSION: This study demonstrates that monitoring pressure through an endoscope is reliable and predictive of true intraabdominal pressure. Gastroscope pressure monitoring is a useful adjunct to NOTES. Future NOTES procedures should incorporate continuous intraabdominal pressure monitoring to avoid the potentially deleterious effects of pneumoperitoneum during NOTES. This can be achieved by the integration of pressure-monitoring capabilities into gastroscopes.

Familial aggregation of Barrett's oesophagus, oesophageal adenocarcinoma, and oesophagogastric junctional adenocarcinoma in Caucasian adults.

BACKGROUND: Although familial clusters of Barrett's oesophagus and oesophageal adenocarcinoma have been reported, a familial predisposition to these diseases has not been systematically investigated. AIMS: To determine whether Barrett's oesophagus and oesophageal (or oesophagogastric junctional) adenocarcinoma aggregate in families. PATIENTS AND METHODS: A structured questionnaire eliciting details on reflux symptoms, exposure history, and family history was given to Caucasian case (n=58) subjects with Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma, and to Caucasian control (n=106) subjects with symptomatic gastro-oesophageal reflux disease without Barrett's oesophagus. Reported diagnoses of family members were confirmed by review of medical records. RESULTS: The presence of a positive family history (that is, first or second degree relative with Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma) was significantly higher among case subjects compared with controls (24% v 5%; p<0.005). Case subjects were more likely to be older (p<0.001) and male (74% v 43% male; p<0.0005) compared with control subjects. In a multivariate logistic regression analysis, family history was independently associated with the presence of Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma (odds ratio 12.23, 95% confidence interval 3.34-44.76) after adjusting for age, sex, and the presence of obesity 10 or more years prior to study enrollment. CONCLUSIONS: Individuals with Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma are more likely to have a positive family history of Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma than individuals without Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma. A positive family history should be considered when making decisions about screening endoscopy in patients with symptoms of gastro-oesophageal reflux.