Safety of nonanesthetist sedation with propofol for outpatient colonoscopy and esophagogastroduodenoscopy.

BACKGROUND AND STUDY AIMS: In our endoscopy service, nonanesthetists administered propofol sedation has been used in more than 8000 procedures during the past 3 years. This study prospectively assessed the safety of propofol sedation in outpatient colonoscopy and esophagogastroduodenoscopy (EGD). PATIENTS AND METHODS: A total of 300 consecutive outpatients (mean age 53, range 14-94) were enrolled in the study (139 colonoscopies, 161 EGDs). After an initial dose of 0.5 mg/kg (ASA I-II and age III or age >70 years), propofol was titrated in 10 mg boluses to a steady state of sedation by the endoscopy nurse under the endoscopist's supervision. Colonoscopy patients also received 25 mg pethidine (meperidine) and 20 mg butylscopolamine, whereas EGDs were performed with propofol sedation alone, without topical pharyngeal anesthesia. In addition to standard monitoring with pulse oximetry and automated sphygmomanometry, patients were also observed with sidestream capnography or measurement of electrocardiographic impedance changes, providing real-time graphic assessment of respiratory activity. All patients were given oxygen 2 L/min by nasal cannula during the entire procedure. RESULTS: Mean dosages of 157 mg (range 70-340) and 180 mg (60-400) propofol were administered for colonoscopy and EGD procedures, respectively. No episodes of apnea occurred. The oxygen saturation fell below 90 % for short periods of time in 11 patients (3.7 %). Three patients required a temporary increase in oxygen delivery. No assisted ventilation was necessary. In 22 patients (7.3 %), the mean blood pressure temporarily decreased below 50 mmHg. Two patients received a 500-ml infusion of normal saline. CONCLUSIONS: Propofol can be safely administered for sedation during colonoscopy and esophagogastroduodenoscopy by nonanesthetists who are familiar with the pharmacological properties and use of this drug.

Methane emissions of differently fed dairy cows and corresponding methane and nitrogen emissions from their manure during storage.

This study investigated the effects of supplementing 40 g lauric acid (C12) kg(-1) dry matter (DM) in feed on methane emissions from early-lactating dairy cows and the associated effects on methane, nitrous oxide and ammonia release from the manure during storage. Stearic acid (C18), a fatty acid without assumed methane-suppressing potential in the digestive tract of ruminants, was added at 40 g kg(-1) DM to a control diet. The complete feed consisted of forage and concentrate in a ratio of 1.5:1 (DM basis). The manure was stored for 14 weeks either as complete slurry or, separately, as urine-rich slurry and farmyard manure representing two common storage systems. Methane release of the cows, as measured in respiratory chambers, was lower with C12 by about 20%, but this was mostly resulting from a reduced feed intake and, partly, from a lower rate of fibre digestion. As milk yield declined less than feed intake, methane emission per kg of milk was significantly lower with C12 (11.4 g) than with C18 (14.0 g). Faeces of C12-fed cows had a higher proportion of undigested fibre and accordingly methane release from their manure was higher compared with the manure obtained from the C18-fed cows. Overall, manure-derived methane accounted for 8.2% and 15.4% of total methane after 7 and 14 weeks of storage, respectively. The evolution of methane widely differed between manure types and dietary treatments, with a retarded onset of release in complete slurry particularly in the C12 treatment. Emissions of nitrous oxide were lower in the manures from the C12 treatment. This partially compensated for the higher methane release from the C12 manure with respect to the greenhouse gas potential. The total greenhouse gas potential (cow and manure together) accounted for 8.7 and 10.5 kg equivalents of CO2 cow(-1) d(-1) with C12 and C18, respectively. At unaffected urine-N proportion ammonia and total nitrogen losses from stored manure were lower with C12 than with C18 corresponding to the differences in feed and nitrogen intake. The present results suggest that manure storage significantly contributes to total methane emission from dairy husbandry, and that the identification of effective dietary mitigation strategies has to consider both the digestive tract of the animals and the corresponding manure.

Safer colonoscopy with patient-controlled analgesia and sedation with propofol and alfentanil.

BACKGROUND: The aim of this study was to assess the efficacy of patient-controlled analgesia and sedation with propofol/alfentanil for colonoscopy compared with continuous drug infusion and conventional nurse-administered medication. METHODS: One hundred fifty patients undergoing colonoscopy on an outpatient basis were randomly assigned to 1 of 3 medication regimens. To maintain blinding, all patients were connected to an infusion pump. Group I patients could self-administer boluses of 4.8 mg propofol and 125 microg alfentanil without restriction. Group II patients received a continuous infusion with 0.048 mg/kg propofol and 0.12 microg/kg alfentanil per minute. Group III patients received intravenous premedication with 0.035 mg/kg midazolam and 0.35 mg/kg meperidine. RESULTS: There were no differences between the groups with respect to pain (visual analogue scale) and procedure time. Patient-controlled analgesia and sedation with propofol/alfentanil (group I) resulted in less of an increase in the transcutaneous partial pressure of carbon dioxide (p = 0.0004) during colonoscopy and less of a decrease in mean arterial blood pressure (p = 0.0021) during recovery, as well as more complete recovery (p = 0.0019) after 45 minutes compared with conventional administration of midazolam/meperidine. Furthermore, patient-controlled analgesia and sedation yielded a higher degree of patient satisfaction than continuous infusion of propofol/alfentanil (p = 0.0033) or nurse-administered midazolam/meperidine (p = 0.0094). CONCLUSIONS: Patient-controlled administration of propofol and alfentanil for colonoscopy may provide a better margin of safety than conventional administration of midazolam and meperidine and results in a higher level of patient satisfaction and shorter recovery.

Is histological investigation of polyps always necessary?

BACKGROUND AND STUDY AIMS: To assess whether polyp histological type can be predicted by patient characteristics and endoscopic polyp findings. PATIENTS AND METHODS: 1681 polyps in 494 patients were categorized as advanced adenomas (villous component or severe dysplasia or early cancer) or insignificant polyps. Chi-squared tests were used to analyze whether polyp histological type could be predicted based on patient age (< 60 vs. > or = 60 years), gender, family history of colon polyps or cancer, presence of anemia, polyp size (< or = 5 mm vs. > 10 mm), and location (left- vs. right-sided). RESULTS: Insignificant polyp histology (n = 1337) correlated with patient age < 60 years (P = 0.0026), lack of anemia (P< 0.0001), polyp size < or = 5 mm (P < 0.0001), and right-sided location (P= 0.0058). Stepwise inclusion of these parameters demonstrated that the association of a < or = 5 mm right-sided polyp in a patient < 60 years yielded the highest combined predictive value (96.2%) for an insignificant polyp. Conversely, age > or = 60 years, presence of anemia, polyp size > 10 mm, or left-sided location, as single or combined parameters, demonstrated a maximum predictive value of only 75.4% for an advanced adenoma. CONCLUSIONS: A small right-sided polyp in a young patient is associated with a small risk (3.8 %) for advanced adenomatous tissue, indicating that histological investigation of such a polyp might not always be necessary. However, the recent recognition of flat adenomas and "mini" de novo colon carcinomas in the European population also may limit the usefulness of small polyp diameters in the exclusion of severe polyp histology.

Transnasal versus transoral endoscopy for the placement of nasoenteral feeding tubes in critically ill patients.

BACKGROUND: Nasoenteral feeding tube placement with the Seldinger technique using transoral endoscopy is a tedious procedure. This study compared the transoral approach with a new technique that uses a transnasal endoscope without the need for a mouth-to-nose wire transfer. METHODS: Critically ill patients requiring nasoenteral feeding tube placement were randomly assigned to the transoral technique using a standard upper endoscope (n = 80) or the transnasal method using a 5.3 mm fiberscope (n = 80). Procedure time, medication requirement, technical difficulty, patient tolerance, and radiologic tube position were assessed. RESULTS: The two groups were similar with regard to baseline medication, endoscopic findings, as well as overall technical difficulty and patient tolerance. The transnasal technique required less procedure time (median 8.0 versus 12.0 minutes, p < 0.001) and less relaxant medication (p = 0.029). Furthermore, it caused fewer circulatory (p = 0.040) and respiratory (p = 0.016) alterations regardless of the application of sedative or relaxant medication. The transnasal endoscope was inferior with respect to passage through the pylorus (p = 0.003) and duodenum (p = 0.020). These differences were significant in univariate hypothesis testing. Bonferroni correction for multiple testing of data removed the significance at p > 0.0031. Both techniques achieved similar rates of successful tube placement in the small bowel (86% versus 84%, p = 0.82). CONCLUSION: Transnasal endoscopy allows accurate placement of nasoenteral feeding tubes in critically ill patients and is superior to transoral endoscopy in terms of procedure time, medication requirement, and safety.

Virtual endoscopy--comparison with colonoscopy in the detection of space-occupying lesions of the colon.

BACKGROUND AND STUDY AIMS: A new technique has been described which combines abdominal helical computed tomography (CT) scanning and virtual reality computer technology, known as virtual colonoscopy (VC); the reconstructed images provide a simulation of the interior of the colon as viewed by endoscopy. We compared VC with conventional colonoscopy in patients with suspected or known colonic neoplasia. PATIENTS AND METHODS: A total of 38 patients, in whom there was a high likelihood of colonic polyps or cancer, underwent a noncontrast helical CT scan of the abdomen and pelvis after regular colonoscopy bowel preparation. The images were reconstructed into a VC presentation and compared with the subsequent conventional colonoscopy in a blinded manner. RESULTS: Conventional colonoscopy identified a total of 24 polyps 5 mm or greater. VC correctly identified five of 13 polyps 5-9 mm in size, and ten of 11 lesions greater than or equal to 10 mm in diameter. The reasons for four missed lesions were identified as being secondary to a collapsed rectum in two patients and stool in the right colon in two patients. The sensitivity and specificity per patient of VC for lesions greater than or equal to 5 mm were 66.7% and 75.0% respectively, and for lesions greater than 1 cm were 90.0% and 82.1%, respectively. CONCLUSIONS: Virtual colonoscopy is feasible, well tolerated, and capable of detecting most lesions greater than 10 mm in diameter. This technique is continuing to be developed and warrants further evaluation as a diagnostic and screening tool in colorectal neoplasia.

Cost analysis of antibiotic prophylaxis for PEG.

BACKGROUND: There are conflicting recommendations regarding the prophylactic use of antibiotics in patients undergoing placement of percutaneous endoscopic gastrostomy tubes. The purpose of this decision analysis was to assess the cost-effectiveness of antibiotic prophylaxis in percutaneous endoscopic gastrostomy. METHODS: A decision tree was modeled using the data of 7 published prospective placebo-controlled trials. Infectious complications were classified as grade I (requiring local care), grade II (requiring intravenous antibiotics), or grade III (requiring surgery). Medication costs were estimated from the United States average wholesale prices of the 1998 Red Book. Physician and facility costs were estimated based on the 1998 Medicare costs. A one-way sensitivity analysis was performed by varying the probability rates of the complications associated with percutaneous endoscopic gastrostomy and the costs of their treatment. RESULTS: The average cost of prophylactic antibiotics was $13.10. Antibiotic prophylaxis led to expected cost savings of $76.72 per percutaneous endoscopic gastrostomy. A sensitivity analysis suggested that antibiotic prophylaxis for percutaneous endoscopic gastrostomy was the preferred strategy unless the average probability of grade III complications dropped below an improbably low threshold value of 0.09%. CONCLUSION: Antibiotic prophylaxis in percutaneous endoscopic gastrostomy is a cost-effective strategy.

In-vivo real-time magnetic resonance monitoring of endoscopic laser applications in the porcine gastrointestinal tract.

BACKGROUND AND STUDY AIMS: Endoscopic laser therapy involves a risk of perforation, mainly because the depth of tissue destruction is not visible. Magnetic resonance (MR) imaging is capable of showing temperature changes, and is therefore suitable for monitoring thermal therapies such as laser. This animal study assessed the feasibility of real-time MR monitoring of endoscopic laser applications in the gastrointestinal tract. MATERIALS AND METHODS: The procedures were carried out using an MR-compatible endoscope in three live pigs in a 0.5-Tesla interventional MR system. Nd:YAG laser applications were performed in the lower gastrointestinal tract (n = 7) and upper gastrointestinal tract (n = 5), and were monitored using real-time color-coded T1-weighted gradient echo sequences. The postmortem macroscopic tissue coagulation sizes were compared with the lesion diameters seen on real-time MR. RESULTS: The endoscope did not cause any artifacts during continuous MR imaging. Ten of the twelve laser lesions were visible with temperature-sensitive MR imaging, and their sizes correlated well with the diameters of the postmortem macroscopic coagulation zones (r = 0.76, P = 0.009). Two laser lesions were not visible on MR due to technical limitations inherent with the healthy animal model. CONCLUSIONS: The formation of endoscopic laser lesions in the porcine gastrointestinal tract can be accurately visualized using real-time temperature-sensitive MR imaging. This new technique has the potential to spare healthy tissue while ensuring full treatment coverage of the targeted lesion with fewer therapy sessions.

Quantitative effects of feed protein reduction and methionine on nitrogen use by cows and nitrogen emission from slurry.

The effects on N use and N volatilization from slurry were investigated in 24 early-lactation Brown Swiss cows (32 kg/d milk) fed four diets with 128, 124, 147 and 175 g/kg DM of crude protein (CP). All diets were supplemented with 0.75 g/kg of rumen-protected Met except for one of the low-protein rations (128 g/kg of CP). The unsupplemented low-protein ration was calculated to be deficient in Met by approximately 20%. No significant treatment effects on performance, water intake and excretion, and slurry quantities were observed. Differences in N intake were closely reflected in the daily excretions of total and urea N via urine, and in urine N as a proportion of total excretory N. These values were higher for the unsupplemented low-protein ration than for the Met-supplemented low-protein ration. The treatment effects on fecal N excretion were generally smaller, and milk N excretion and N balance were not affected. Feed N utilization for milk N excretion increased with decreasing CP content from 27% for the high-protein group to about 35% for the two low-protein groups. Comparing the Met supplemented rations only, ammonia N emission from fresh slurry (excreta:water = 1:0.5) decreased from 231 to 160 and 55 microg/s per square meter of surface with 175, 147 and 124 g/kg of CP, respectively, and the corresponding total N losses during 7 wk of slurry storage declined from 89 to 57 and 25 g/d per cow. Regression analysis demonstrated the basic suitability of milk urea N excretion to estimate urine N excretion and, consequently, potential N emissions.

Endoscopic injection of bleeding esophageal varices with a poly-N-acetyl glucosamine gel formulation in the canine portal hypertension model.

BACKGROUND: It has been shown that poly-N-acetyl glucosamine produces rapid hemostasis by stimulating erythrocyte aggregation. Endoscopic injection of this substance may be effective in the treatment of bleeding varices. METHODS: In eight heparinized dogs with a bleeding esophageal varix greater than 2 mm in diameter, 2.5% to 3.5% poly-N-acetyl glucosamine gel was injected intravariceally and paravariceally. Endoscopy, endosonography, and histopathology were performed at 1, 7, 21, and 90 days after injection. RESULTS: In all cases, the variceal hemorrhage was stopped with three to four injections of a mean total gel volume of 1.9 mL. No recurrence of bleeding, ulceration, or stricture formation occurred. Through replacement of the gel by connective tissue, the varix was permanently obliterated in its whole course in five cases and in more than 70% of its length in three cases. No embolization and no poly-N-acetyl glucosamine antibodies were detected. CONCLUSIONS: Endoscopic injection of bleeding esophageal varices in this animal model with the use of poly-N-acetyl glucosamine gel was an effective and safe method for stopping the hemorrhage and inducing permanent varix obliteration.

Local staging of anal and distal colorectal tumors with the magnetic resonance endoscope.

BACKGROUND: We prospectively assessed the feasibility and accuracy of endoscopic magnetic resonance (EMR) scanning in the local staging of anal and colorectal cancer as compared to endosonography. METHODS: Fifteen patients with biopsy-proven anal (n = 2), rectal (n = 11), and distal colonic (n = 2) cancer underwent endosonography followed by EMR imaging. Scans were acquired using the magnetic resonance receiver coil incorporated into the tip of the non-ferromagnetic endoscope. Blinded to endosonography results, two radiologists interpreted the EMR images using the TNM system. Staging results were compared to endosonography in all patients and to histopathology in the 13 colorectal cases. RESULTS: EMR imaging, well tolerated in all patients, correlated with endosonography in 10 of 15 and 12 of 15 cases for T- and N-staging, respectively. In the 13 colorectal patients with available histopathology, accuracy of EMR and of endosonography in T-staging was 77% and 85%, respectively; N-staging accuracy was 62% for both. CONCLUSIONS: For anal and distal colorectal neoplasms, EMR imaging is feasible and provides local staging comparable to endosonography.

Newer antiepileptic drugs: gabapentin, lamotrigine, felbamate, topiramate and fosphenytoin.

Twenty-five to 40 percent of patients with epilepsy continue to have seizures despite optimal treatment with traditional antiepileptic drugs. Treatment with standard anticonvulsants such as phenytoin, carbamazepine, valproic acid and phenobarbital is often complicated by side effects and by failure to adequately control seizures. Up to 61 percent of patients with seizures report having side effects with antiepileptic drugs. After a 15-year hiatus since the last new antiepileptic drug was marketed, five new drugs have been approved by the U.S. Food and Drug Administration for the control of seizures. Three of these, gabapentin, lamotrigine and topiramate, are approved for use in adults with partial seizures with or without generalization. Felbamate is approved for the above indication and also for use in children with Lennox-Gastaut syndrome, a rare childhood seizure disorder. Felbamate and lamotrigine have the potential of significant side effects and should be prescribed by physicians experienced in managing patients with complicated epilepsy. Fosphenytoin is a parenteral prodrug of phenytoin that is more tolerable than parenteral phenytoin.

Local staging of esophageal cancer using endoscopic magnetic resonance imaging: prospective comparison with endoscopic ultrasound.

BACKGROUND AND STUDY AIMS: The magnetic resonance endoscope consists of a non-ferrous endoscope with a radiofrequency receiver coil incorporated into its tip. The aim of this study was to assess the accuracy of endoscopic magnetic resonance imaging for the local staging of esophageal cancer. PATIENTS AND METHODS: Prospectively, 15 patients with biopsy-proven cancer of the esophagus (n = 9) or gastroesophageal junction (n = 6) underwent endosonography followed by imaging by the magnetic resonance endoscope. The results of endoscopic magnetic resonance imaging were assessed blindly, then compared with those of endosonography, which served as the gold standard. RESULTS: Endoscopic magnetic resonance imaging of transmural tumor invasion agreed with ultrasonography in 11/15 cases and of nodal state in 12/15 cases. Endoscopic magnetic resonance images were inadequate in four cases as a result of motion artifacts. CONCLUSIONS: Endoscopic magnetic resonance imaging of esophageal cancer diagnoses local staging that is comparable to endosonography. In future, the combination of endoscopic and conventional magnetic resonance scanning may provide comprehensive staging of esophageal cancer.