[The virtual discussion: a new model of clinical session].
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Computer-Assisted Instruction↗
Biomedical subjects
R Calabuig
Publications and source records attributed to R Calabuig.
[Central venous catheter location by endocavitary ECG: an alternative to chest radiography].
BACKGROUND: The location of a central venous catheter is checked with a chest radiograph. Right endocavitary electrocardiography (ECG), a technique in which the catheter is connected to the ECG recorder wire to record ECG in DII, might be an alternate method to check the position of the catheter. When the catheter enters the right atrium, there is a large increase in the amplitude of P wave. The aim of this study was to compare the efficacy of endocavitary ECG against the chest radiography as a method to check the position of a central catheter, and to determine whether the ECG method can replace the radiological method. MATERIAL AND METHODS: One-hundred central catheters which location was checked by ECG and by chest X-ray entered the study. Efficacy of endocavitary ECG, delay between catheter insertion and radiological check, and the cost of the two methods were studied. RESULTS: Endocavitary ECG determined that de catheter was in a correct position in 80 cases and malpositioned in 20 cases. ECG check agreed with radiological check in 93 catheters. There were 4 false-positive and 3 false-negative cases. The efficacy of endocavitary ECG was 93% (sensitivity: 82%; specificity: 81%; positive predictive rate: 95%; negative predictive rate: 85%). Catheter location was checked immediately on insertion by ECG in all cases, while radiological check was delayed 32 +/- 25 min in the emergency department and 68 +/- 206 min in the admitted patients. The cost of the ECG method was less than that of the radiological method. CONCLUSIONS: The check of the position of a central venous catheter by endocavitary ECG is taster, cheaper, and of similar efficacy to the radiological method. Endocavitary ECG can replace chest X-rays to check the position of the catheter in more than 90% of cases.
Catheterization, Central Venous↗
Gallbladder dyskinesia in acalculous biliary colic.
AIMS: To test the hypotheses that: 1) postprandial gallbladder emptying might be abnormal in patients with acalculous biliary colic; and 2) that hymecromone, a drug that increases bile flow and relaxes biliary muscle might improve symptoms. METHODS: Twenty-four women were studied. Twelve patients presented recurrent biliary type of pain in the absence of gallstones, and persistence of contrast in the gallbladder, 24 hours after an oral cholecystogram, suggesting cholesterolosis. Twelve healthy volunteers used as controls had no symptoms and the gallbladder was not visible the day after an oral cholecystogram. Gallbladder emptying induced by an oral meal was studied with ultrasound in both groups before and after the administration of hymecromone. RESULTS: Gallbladder volumes were similar in both groups (23 +/- 10 ml vs. 31 +/- 11 ml; NS). Gallbladder emptying in the control group was simple exponential (R2 = 0.948 +/- 0.059) with a rate of 32 +/- 16 minutes. Gallbladder emptying was bimodal in patients. Gallbladder volume increased to 120% in the first 10 minutes, to empty exponentially thereafter (R2 = 0.964 +/- 0.040. Rate: 29 +/- 22 minutes). This resulted in a marked reduction in gallbladder volume emptied at 40 minutes when compared to controls (30% +/- 27% vs. 54% +/- 14%; p = 0.012). Pretreatment of controls with hymecromone induced an emptying pattern similar to that of patients. In patients, emptying after hymecromone did not change but symptoms were improved. CONCLUSIONS: An abnormal emptying pattern of the gallbladder was identified in patients with acalculous biliary colic, and hymecromone was partly effective to reduce pain, despite a minor effect on gallbladder emptying pattern.
Biliary Tract Diseases↗
[Efficacy of the ilioinguinal and iliohypogastric block in the treatment of the postoperative pain of inguinal herniorrhaphy].
INTRODUCTION: The ileoinguinal-ileohypogastric block (IHB) improves pain control in inguinal hernioplasty. OBJECTIVE: To determine the efficacy of the IHB on the treatment of postoperative pain in inguinal herniorrhaphy, and to compare the effect of its use before and after incision for diminishing pain and postponing the first dose of analgesia. PATIENTS AND METHODS: Sixty-eight patients scheduled for inguinal herniorrhaphy with mesh were enrolled and distributed randomly in 4 groups as follows: 1) IHB before incision using 0.25 ml/kg bupivacaine 0.5% with no vasoconstrictor; 2) IHB after incision with the same dose of bupivacaine; 3) IHB before incision with 0.25 ml/kg of serum; and 4) IHB after incision with 0.25 ml/kg of serum. Pain was evaluated on visual analog scales employing facial expressions and verbal description, a patient questionnaire and time elapsing between surgery and the first dose of analgesia. The evaluations were performed in the postoperative recovery unit and on the ward 8 and 24 hours after surgery. RESULTS: The total overall score for postoperative pain was lower in the bupivacaine group than in the placebo group (9.2 +/- 4.4 and 1.5 +/- 3.9, respectively; p = 0.026). The first dose of analgesia was given to those who received placebo between the second and third hour after surgery, whereas it was given between the fourth and fifth hour to the bupivacaine group. No significant differences were found between infiltration before and after incision. CONCLUSIONS: IHB decreases pain, delaying the need for a first dose of analgesic and improving patient comfort. Its use is therefore recommended for relief of postoperative pain.
Double-Blind Method↗
Ileo-cecal junction: a valve or a sphincter? An experimental study in the opossum.
The characteristics of the ileo-junction (UIC) were examined in seven opossums in vivo, and the effect of the UIC on colo-ileal reflux in eight opossums in vitro. Electromyography and intraluminal manometry were studied during intestinal distensions, and administration of phenylephrine, isoproterenol and carbachol. In vitro studies used preparations of ileum, UIC, and colon, attached to a propulsion evaluation system. Fluid flow across the UIC was studied basally and after phenylephrine, isoproterenol and carbachol. A high pressure zone in the UIC was not observed in vivo. Colonic distension increased the pressure and electrical spike bursts in the ileum and UIC, while ileal distension had the opposite effect. Myoelectric and contractile activities were inhibited by adrenergic agonists and stimulated by carbachol. In vitro studies demonstrated aborally migrating ileal contractions initiated by fluid injections into the ileum, and cecal contractions elicited by fluid injections into the colon. The UIC only prevented colo-ileal reflux when it was undergoing contraction as part of ileal or colonic activity. These findings suggest that the opossum UIC does not have valvular properties and ileal fluid propulsion is the main factor in the prevention of colo-ileal reflux.
Action Potentials↗
Mathematical analysis of epidural space location.
BACKGROUND: The location of epidural space for local anaesthetic injection can be difficult. The aim of this study was to define the mathematical function of the pressure changes in the syringe during puncture of the epidural space. Knowledge of pressure changes might be of help to the anesthetist who attempts to ascertain the location of the needle, and it is essential to the design of a device with which to locate epidural space. METHODS: Epidural punctures were performed in 20 patients, using an 18-Tuohy needle connected to a 10 ml syringe. The epidural space was located by the loss of resistance technique. Pressure variations within the injection system during epidural puncture were measured and digitized at 250 Hz. Pressure curves were analyzed for amplitude and rate of a decay after entry of the needle into the epidural space. RESULTS: Pressure increased as the needle passed through skin, subcutaneous fat and muscle. The maximal pressure was observed when the needle perforated the ligamentum flavum (689 +/- 124 cm H2O). When the needle entered the epidural space, an exponential decrease in pressure was observed in all patients (R2 = 0.99; tau = 2.1 +/- 0.9 seconds). End-residual pressure was 22 +/- 12 cm H2O. The change in pressure observed when the needle entered the epidural space fitted a negative exponential function (y = e-x/2.08). CONCLUSIONS: Pressures within the injection system for epidural puncture can reach 1100 cm H2O. Location of the epidural space is characterized by an exponential decay to and end-residual pressure below 50 cm H2O, with a constant time of approximately 2 seconds.
Adolescent↗
Influence of the menstrual cycle and of menopause on the gastric emptying rate of solids in female volunteers.
The aim of this study was to assess the influence of the normal menstrual cycle and of menopause on the gastric emptying rate of solids. Gastric emptying was studied in 15 premenopausal and ten postmenopausal women with an isotopic technique after the ingestion of a radiolabelled test meal. Premenopausal women were studied twice: within 1 week prior to menses and again 1 week after onset of menses. Postmenopausal women were studied only once. The emptying curves of the solid component of the meal fitted a linear model. The half-emptying time was 78 +/- 5 min during the follicular phase, 75 +/- 7 min during the luteal phase and 76 +/- 6 min in postmenopausal women (differences not statistically significant). The mean percentages of the meal retained in the stomach at different time intervals were also similar in the three groups. These results suggest that the menstrual cycle does not influence the gastric emptying rate of solids, which remains unchanged in relation to the follicular phase or after menopause.
Adult↗
[Dysfunction of the Oddi's sphincter].
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Common Bile Duct Diseases↗
Anatomy of the bilioduodenal junction of the opossum.
Prevention of reflux is a major function of the terminal biliary duct system at its junction with the duodenum. We examined this area via scanning electron microscopy and light microscopy to explore anatomic features that might play such a role in the Virginia opossum, a species with a highly developed sphincter of Oddi (SO). The terminal apparatus, most of which consists of a dilated extramural ampulla, has a lumen with abundant folds. Mucus is produced by the lining epithelium and by a plethora of glands. Three muscle layers constitute the SO: an inner longitudinal, an outer circular, and a less consistent outermost longitudinal. The terminal apparatus forms an acute angle and narrows as it enters the duodenum; at this point, the SO becomes continuous with the muscularis externa of the intestine. Four anatomical features with potential antireflux properties may be identified: mucus production, luminal folds, and the narrow opening and oblique course of the intramural duct.
Animals↗
Bacterial flora of the gastrointestinal tract of opossums.
The bacterial flora of the stomach, small intestine, cecum and bile from 20 healthy opossums (Didelphis virginiana) captured from the wild was studied. Results showed that their gastrointestinal flora was similar to that found in other small mammals but, in addition, opossums are heavily colonized by Salmonella spp., which might adversely affect their adequacy as laboratory animals for some experimental protocols.
Animals↗
Effects of pentagastrin and of the somatostatin analog (SMS 201-995) on growth of CT26 in vivo adenocarcinoma of the colon.
This study was done to investigate the effects of pentagastrin and of somatostatin analog (SMS 201-995) on growth of CT26 adenocarcinoma of the colon implanted in mice. Eighty Balb C mice were inoculated subcutaneously with 100,000 cells. Four groups of 20 mice each were treated with 0.1 milliliters of saline solution every eight hours; 250 micrograms per kilogram of pentagastrin every eight hours; 100 micrograms per kilogram of SMS 201-995 every 12 hours; 250 micrograms per kilogram of pentagastrin every eight hours, plus 100 micrograms per kilogram of SMS 201-995 every 12 hours. Tumoral weight, volume and deoxyribonucleic acid (DNA) content and mean survival rates were determined for each group. Control mice had tumors weighing 1,619 +/- 179 milligrams, of 1.47 +/- 0.2 milliliters to the third power and with 12.9 +/- 1.1 milligram of DNA, at 30 days after inoculation. The mean survival rate was 42.5 days. Pentagastrin administration increased the three parameters of tumoral growth by 40 percent and reduced survival time to 29.6 days (p < 0.01), while SMS 201-995 inhibited growth by 40 percent and prolonged survival time to 48.5 days (p < 0.01). Simultaneous administration of both peptides had no effects. These data suggest that pentagastrin has a trophic effect and SMS 201-995 an inhibitory effect on CT26 adenocarcinoma in mice.
Adenocarcinoma↗
Transduodenal sphincteroplasty with transampullary septectomy for stenosing papillitis.
The papilla of Vater and its sphincter of Oddi, lying at the confluence of the bile and pancreatic ducts in man, have long been suspected as a source of upper abdominal pain. Enlarging the opening of the transpapillary segment of the bile and major pancreatic ducts by using a transduodenal sphincteroplasty with transampullary septectomy resulted in death in a patient with a peripapillary diverticulum and pancreas divisum. Eight-six patients followed for 1 to 10 years experienced a 75% success rate. Thirty-six patients had a marked stenosis of their duct of Wirsung, suggesting that their pain was primarily from the pancreas. The remainder had either a generalized narrowing (40 patients) or a normal (7 patients) papilla. Pain was not satisfactorily resolved in patients with an associated pancreas divisum, chronic pancreatitis, and recurrent episodes of acute pancreatitis with alcoholism.
Abdominal Pain↗
Immunological sensitization of opossum gallbladder by naturally acquired stomach roundworm infection.
1. The opossum gallbladder develops an immediate type hypersensitivity as a result of chronic infection with the gastric nematode, Physaloptera turgida. 2. Hypersensitization is evident from a change in net transepithelial ion transport in response to parasite-derived antigen. 3. The antigen-induced change in ion transport involves mediation by histamine and possibly prostaglandins and is independent of intrinsic neural modulation. 4. The functions of the gallbladder epithelium are influenced by reactions of local immune elements that are part of the common mucosal immune system.
Animals↗
Gastric emptying of two radiolabelled antacids.
The rate of gastric emptying of two antacids, magaldrate and Maalox, was investigated using scintigraphy. Successful labelling of the antacids was carried out with 99mTc. The stability of the 99mTc-labelled antacids was satisfactory and there was no difference in antacid capacity between the labelled and unlabelled antacids. The studies were carried out on 15 healthy male volunteers. After an eight hour fast each subject ingested a standardised meal of 95.7 MJ (400 kcal). One hour later 10 ml of one of the two antacids previously labelled with 99mTc was administered. Serial detection by anterior and posterior projection of the amount of antacid retained in the stomach was performed to determine gastric emptying of antacid. One week later the study was repeated under the same conditions with the other antacid also labelled with 99mTc. The mean (SD) percentages of antacid retained in the stomach fit a linear model with a t1/2 of 86.6 (15.3) minutes for magaldrate and 52.3 (5.2) minutes for Maalox (p less than 0.01). When the mean percentages of retention at six time intervals were compared for both antacids, it was found that Maalox emptied much faster (p less than 0.01 at 15 and 30 minutes, p less than 0.02 at 45, 60, 75, and 90 minutes).
Adult↗
Choledochoduodenal flow: effect of the sphincter of Oddi in opossums and cats.
The aim of this study was to test in vivo (a) whether the sphincter of Oddi acts as a resistor or also as a pump, (b) the effect of an IV infusion of cholecystokinin (CCK) on choledochoduodenal flow, and (c) the ability of the choledochoduodenal junction to prevent duodenobiliary reflux in two animal species, opossums (n = 11) and cats (n = 8). Opossums were implanted with bipolar electrodes on the sphincter of Oddi and the adjacent duodenum. Cats were not. Experiments were performed in vivo using a propulsion evaluation system to test whether the Sphincter of Oddi was able to pump fluid from the bile duct to the duodenum against pressure gradients. In 5 opossums and 4 cats, choledochoduodenal flow was evaluated during the IV infusion of CCK (20 ng.kg-1.min-1). The opossum sphincter of Oddi moved fluid against duodenal pressure gradients of 6-45 cm H2O. The spike-burst frequency (6.4 +/- 1.7 min-1) was maximal at peak bile duct pressures and decreased as bile duct pressure decreased (4.9 +/- 1.6 min-1; P less than 0.001). Pressure pulses in the bile duct were observed at a frequency that correlated with sphincter of Oddi spike-burst frequency (r = 0.84; P less than 0.001). In cats, choledochoduodenal flow occurred only along a hydrostatic gradient; the sphincter of Oddi never acted as a pump but only as a resistor. Infusion of CCk significantly increased the frequency of sphincter of Oddi contractions in opossums, but the transfer of fluid from bile duct to duodenum was significantly reduced. In cats, the rate of fluid flow from the bile duct to the duodenum during CCK infusion did not differ from control values. Reflux of duodenal fluid into the biliary tree was never observed, even at duodenal pressures as high as 100 cm H2O. In conclusion, in vivo, the sphincter of Oddi is able to pump fluid from the bile duct to the duodenum against a pressure gradient in opossums, but, in cats, choledochoduodenal flow requires a bilioduodenal pressure gradient. The increase in sphincter of Oddi contraction frequency induced by CCK in opossums resulted in a decrease in active transsphincteric flow. Duodenobiliary reflux could not be elicited in opossums and cats under the conditions of these experiments.
Animals↗
Stenosis of the sphincter of Oddi.
"Stenosing papillitis" is a descriptive term for an anatomic deformity of the papilla of Vater that is characterized by narrowing of the lower end of the bile duct and the proximal end of the duct of Wirsung. The defect is secondary to inflammation and fibrosis from the chronic passage of gallstones, episodes of acute pancreatitis, chronic pancreatitis, sclerosing cholangitis, peptic ulcer disease, and cholesterolosis. Patients with papillary stenosis from gallstones may present with episodes of severe upper-abdominal pain several years after cholecystectomy. The pain is often incapacitating, and patients are often addicted to narcotic analgesics. The work-up includes abdominal ultrasonography and CT scanning and endoscopic retrograde cholangiopancreatography even though the findings usually are normal. Liver and pancreatic enzymes are not frequently elevated with the painful episodes. Transendoscopic manometry may reveal elevated pressures within the papillary portion of the distal bile duct. Some patients are relieved of their pain by transduodenal sphincteroplasty and transampullary septectomy, thereby ablating the sphincter of Oddi around the bile and pancreatic ducts and enlarging their openings.
Cholestasis, Extrahepatic↗
Biliary and gut function following shock.
The aim of this study was to characterize the alterations in gallbladder and intestinal function after hemorrhagic shock and blood reperfusion in opossums. Animals were subjected to a shock of 30 mm Hg of arterial blood pressure for 60 minutes and resuscitated with blood reinfusion. Gallbladder epithelial ion transport, gallbladder motility in vitro and in vivo, gastrointestinal motility, and flora of the stomach and small bowel were studied 2 and 24 hours after shock. Changes at 2 hours included decreased gallbladder contractility in vitro and decreased emptying in vivo, loss of coordination with intestinal motor activity, decrease in frequency of intestinal electrical slow waves, and reduced duration of the intestinal migrating motor complex cycle. By 24 hours, gallbladder epithelial permeability was increased and in vitro contractility remained reduced but the in vivo functions showed partial recovery. Gastrointestinal flora was not affected by these changes. These data demonstrate that hemorrhagic shock and reperfusion affect digestive motility. The early timing of the alterations observed and the partial recovery 24 hours post shock suggest an ischemia-hypoxia mechanism of injury.
Animals↗