Biomedical subjects

H Athanasakis

Publications and source records attributed to H Athanasakis.

6 recordsLinked to original sources

PubMed2002

Lung emptying in patients with acute respiratory distress syndrome: effects of positive end-expiratory pressure.

The pattern of lung emptying was studied in 10 mechanically-ventilated patients with acute respiratory distress syndrome. At four levels of positive end-expiratory pressure (PEEP) (0, 5, 10 and 15 cmH2O) tracheal (Ptr) and airway pressures (Paw), flow (V') and volume (V) were continuously recorded. Tidal volume was set between 0.5-0.6 L and V'/V curves during passive expiration were obtained. Expired volume was divided into five equal volume slices and the time constant (taue) and effective deflation compliance (Crs(eff)) of each slice was calculated by regression analysis of V/V' and postocclusion V/Ptr relationships, respectively. In each slice, the presence or absence of flow limitation was examined by comparing V'/V curves with and without decreasing Paw. For a given slice, total expiratory resistance (Rtot) (consisting of the respiratory system (Rrs), endotracheal tube (Rtube) and ventilator circuit (Rvent)) was calculated as the taue/Crs(eff) ratio. In the absence of flow limitation Rrs was obtained by subtracting Rtube and Rvent from Rtot, while in the presence of flow limitation Rrs equaled Rtot. The taue of the pure respiratory system (taue(rs)) was calculated as the product of Rrs and Crs(eff). At zero PEEP, taue(rs) increased significantly towards the end of expiration (52+/-31%) due to a significant increase in Rrs (46+/-36%). Application of PEEP significantly decreased Rrs at the end of expiration and resulted in a faster and relatively constant rate of lung emptying. In conclusion, without positive end-expiratory pressure the respiratory system in patients with acute respiratory distress syndrome deflates with a rate that progressively decreases, due to a considerable increase in expiratory resistance at low lung volumes. Application of positive end-expiratory pressure decreases the expiratory resistance, probably by preventing airway closure, and as a result modifies the pattern of lung emptying.

Adult↗

PubMed2001

Laparoscopically assisted subtotal colectomy for slow-transit constipation.

BACKGROUND: When medical therapy fails, slow-transit constipation (STC), a condition seen almost exclusively in women, can be treated surgically. The aim of this study was to describe our results with laparoscopically assisted subtotal colectomy (LASC) for STC. METHODS: Over a 22-month period, four female patients underwent LASC with ileorectal anastomosis for STC at our hospital. The preoperative workup included clinical assessment, evacuation proctography, rectoanal manometry, and colonic transit measurement. Mobilization of the whole colon and ligation and division of colonic mesenteric vessels with preservation of the omentum were achieved laparoscopically. Through a small Pfannenstiel incision, the colon was removed from the abdomen, leaving a 15-cm rectal stump in situ. The rectal stump was fully mobilized posteriorly, a side-to-end ileorectal anastomosis was fashioned, and the rectal stump was fixed onto the presacral fascia with sutures. RESULTS: The operating time ranged from 150 to 260 min and blood loss was minimal. There were no conversions to open surgery. The postoperative course was uneventful in all patients but one, a 47-year old woman who had transient severe abdominal distension, pain, and frequent small-volume bowel movements. All patients were discharged by the 4th to 10th postoperative day. At 9-month follow-up, all of our patients had normal anorectal function with two to four solid bowel movements per day. CONCLUSION: Although it is a technically demanding procedure, laparoscopically assisted colectomy for slow-transit constipation, can be achieved safely.

Adult↗

PubMed2001

Prospective randomized trial comparing Nissen to Nissen-Rossetti technique for laparoscopic fundoplication.

BACKGROUND: It has been suggested that division of the short gastric vessels (SGV) provides a more floppy Nissen fundoplication, for the treatment of reflux disease. The aim of the study was to assess whether Nissen fundoplication with division of SGV is associated with improved clinical outcome and laboratory findings. METHODS: Fifty-six consecutive patients with gastroesophageal reflux disease (GERD) were randomly assigned to have a laparoscopic Nissen fundoplication either with division (24 patients; 15 men; mean age 51 +/- 15 years) or without division (32 patients; 23 men, mean age 47 +/- 14 years) of the SGV. Preoperative and postoperative investigation included clinical assessment, esophagoscopy, esophagogram, esophageal manometry, and 24-hour ambulatory esophageal pH monitoring. RESULTS: Division of the SGV resulted in a significant increase of the operating time (P <0.0001). The operation abolished reflux in both groups. Also, both types of Nissen fundoplication significantly increased the amplitude of peristalsis at distal esophagus (division group: from 56 +/- 20 mm Hg to 64 +/- 25 mm Hg, P = 0.01; nondivision group: from 65 +/- 27 mm Hg to 75 +/- 26 mm Hg, P <0.001) and the lower esophageal sphincter pressure (division group: from 16 +/- 10 mm Hg to 24 +/- 7 mm Hg, P <0.001; nondivision group: from 22 +/- 8 mm Hg to 28 +/- 5 mm Hg, P <0.001). No differences in the incidence of postoperative severe dysphagia (division group: 5 of 24; nondivision group: 3 of 32) and overall esophageal transit were accounted between groups. However, division of the SGV was associated with a significant increased incidence of gas-bloating syndrome (division group, 13 of 24, versus nondivision group, 9 of 32, P = 0.02). CONCLUSIONS: Division of the SGV at laparoscopic Nissen fundoplication for GERD does not improve clinical outcome and laboratory findings, while it is associated with prolongation of the operating time and increased incidence of gas-bloating syndrome.

Deglutition Disorders↗

PubMed2001

Laparoscopic repair of paraesophageal hernia.

BACKGROUND AND STUDY AIMS: Surgical repair of paraesophageal hernia is mandatory, due to the risk of severe complications, and it can be accomplished via the laparoscopic route. This study presents the results of laparoscopic repair of paraesophageal hernia combined with anterior hemifundoplication. PATIENTS AND METHODS: During a two-year period, ten consecutive patients with paraesophageal hernia (six men, four women; mean age 73, range 55-82) underwent laparoscopic treatment. Five patients presented with symptoms of gastroesophageal reflux, while another four reported lower chest pain. There was one patient in whom the paraesophageal hernia was manifested with upper gastrointestinal bleeding. Six patients had type III hiatal hernia. They all underwent esophagography, upper gastrointestinal endoscopy, stationary manometry, and 24-hour ambulatory pH-metry, preoperatively and within three months postoperatively. At laparoscopy, the hernia content was completely reduced, the sac excised, and the diaphragmatic crura approximated. The operation was completed with an anterior hemifundoplication. In three cases, a prosthetic mesh was applied to close the hiatal defect securely. RESULTS: Operating times ranged from 75 min to 125 min (mean 90 min). There were no postoperative deaths. One patient developed atelectasis, and another had empyema of the left pleura, treated with drainage and antibiotics. All patients but one were discharged on the second or third postoperative day. At the three-month follow-up examination, none of the patients had symptoms related to the paraesophageal hernia, gastroesophageal reflux, or fundoplication. Esophagography demonstrated restoration of normal anatomy at the gastroesophageal region, while esophageal motility was improved, and esophageal pH-metry showed no gastroesophageal reflux. CONCLUSION: Laparoscopic repair of paraesophageal hernias is a safe, technically feasible, and well tolerated procedure, which offers rapid and total relief of symptoms. The addition of an anterior hemifundoplication not only cures preexisting gastroesophageal reflux, but also prevents the development of postoperative gastroesophageal reflux.

Aged↗

PubMed2000

The effect of erythromycin on human esophageal motility is mediated by serotonin receptors.

OBJECTIVE: Erythromycin exhibits prokinetic properties. The drug enhances esophageal and gastric motility by acting as a motilin agonist and promoting acetylocholine release. 5-HT3 receptors are involved in the spontaneously occurring migrating motor complex and the effect of erythromycin on antral motility in dogs. The aim of the study was to investigate the hypothesis that 5-HT3 receptors are also involved in the action of erythromycin on the human esophagus. METHODS: A total of 18 healthy volunteers underwent standard esophageal manometry on three different occasions in a double-blind, placebo-controlled, randomized manner, as follows: 1) after placebo, 2) after 200 mg of erythromycin i.v., and 3) after 200 mg of i.v. erythromycin subsequent to pretreatment with either 4 mg of i. v. ondansetron (serotonin receptor antagonist) (10 subjects) or 12 microg/kg of i.v. atropine (8 subjects). RESULTS: Erythromycin significantly increased a) the amplitude of peristalsis at 5 cm (from 87 +/- 19 mm Hg to 108 +/- 26 mm Hg; p = 0.0007), 10 cm (from 72 +/- 24 mm Hg to 81 +/- 26 mm Hg; p = 0.016), and 15 cm (from 47 +/- 15 mm Hg to 55 +/- 17 mm Hg; p = 0.014) proximal to LES, b) the duration of peristalsis at 5 cm (from 4.5 +/- 0.9 s to 5.7 +/- 1.2 s; p < 0.0001) and 10 cm (from 4.1 +/- 1 s to 4.9 +/- 1 s; p < 0.0001) proximal to the LES and c) the strength of peristalsis at 5 cm proximal to the LES (from 180 +/- 49 mm Hg x s to 276 +/- 100 mm Hg x s; p < 0.0001), and decreased the velocity of peristalsis at distal esophagus (from 4.1 +/- 1 cm/s to 3.8 +/- 0.9 cm/s; p = 0.03). In addition, erythromycin significantly increased the resting pressure of the LES (from 36 +/- 10 mm Hg to 44 +/- 12 mm Hg; p = 0.002). Pretreatment with ondansetron totally reversed all of the effects of erythromycin to the placebo state. Pretreatment with atropine not only prevented the effects of erythromycin, but it reduced the amplitude and strength of peristalsis at the distal esophagus at significantly lower levels than after placebo. CONCLUSIONS: Erythromycin exerts its prokinetic action on the lower esophagus by stimulating cholinergic pathways. This action includes not only an increase in LES pressure, but significant increases in the amplitude and duration of esophageal peristalsis, as well. 5-HT3 receptors are also involved in this process.

Adult↗

PubMedDate not supplied

Treatment of unresectable malignant abdominal, pelvic and thoracic tumors using abdominal pelvic and thoracic stop-flow chemotherapy.

BACKGROUND: Stop-flow perfusion (SFP) has been recently used to enhance the effects of chemotherapy in patients with locally advanced tumors. PATIENTS AND METHODS: Over a 2-year period we performed abdominal, pelvic and thoracic SFP in 12 patients with unresectable or metastatic tumors, using balloon catheters inserted into the abdominal aorta and inferior vena cava. Blood flow was occluded and hypoxic extracorporeal perfusion or SFP was performed for advanced diseases. The chemotherapeutic agents were directly administered into the aorta and/or inferior vena cava for thoracic SFP. The procedure was repeated in each patient, with one-month interval between sessions. Haemofiltration was also applied in two patients with generalized abdominal disease in order to reduce systemic toxicity. RESULTS: At post-operative CT or MRI follow-up, tumor shrinkage of more than 50% was observed in six patients, while post-SFP chemotherapy surgical resection of the tumors became feasible in four cases. The relief of pain, wherever present, was dramatic in the immediate post-operative period. Overall clinical improvement was achieved in all 12 patients. Post-operative recovery was uneventful in all but two patients, who developed minor systemic toxicity. CONCLUSION: SFP appears to be a safe technique with low morbidity which improves the quality of life of cancer patients and allows satisfactory control of locally advanced tumors and metastatic carcinomatosis.

Abdominal Neoplasms↗