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Biomedical subjects

A Cuschieri

Publications and source records attributed to A Cuschieri.

At least 109 records · Page 6Linked to original sources
PubMed1999

Do patients with acute abdominal pain wait unduly long for analgesia?

A prospective audit of 100 emergency admissions was carried out to determine local surgical practice for analgesia administration in patients with acute abdominal pain. The main outcome measure investigated was waiting time for analgesia and how this was influenced by (i) severity of pain, (ii) clinical diagnosis, (iii) clinical setting. The data were correlated with the results of a questionnaire on timing of analgesia. Forty percent of patients received analgesia within 1 h, 17% between 1-2 h, and 43% 2-22 h after admission. Mean waiting time was 2.3 h with severe pain (n = 84) vs. 6.3 h with moderate pain (n = 16, p < 0.0001, Mann-Whitney). Clinical diagnosis did not influence timing of analgesia. Fifty-seven per cent received analgesia in the Accident and Emergency (A&E) department with a mean wait of 60 min, whereas 43% admitted to the ward without analgesia in the A&E department waited an average of 5.7 h for pain medication (p < 0.0001; Mann-Whitney U-test). This was at variance with local surgical opinion that favoured early analgesia administration (yes-88%), in the absence of a firm diagnosis (yes-79%), although 38% stated that analgesia might mask physical signs. In conclusion, a substantial cohort of patients with acute abdominal pain (43%) wait too long for analgesia. Delays are due to omission of analgesia in A&E, and reluctance of junior staff to administer analgesia for fear of masking physical signs. Clinical guidelines for pain medication in acute surgical emergencies are warranted.

Abdomen, Acute↗
PubMed1999

Laparoscopic cholecystectomy.

Laparoscopic cholecystecomy is now the gold standard for the treatment of gallstones. When it was first introduced there were some concerns about its safety owing to its rapid adoption by untrained surgeons. However, when a careful, correct technique is employed, the operation is extremely safe. This article describes a well established technique for laparoscopic cholecystectomy, which has been evolved over several years in a centre that has concentrated on the development of laparoscopic surgery.

Cholangiography↗
PubMed1998

Randomised study of influence of two-dimensional versus three-dimensional imaging on performance of laparoscopic cholecystectomy.

BACKGROUND: Several three-dimensional video-endoscopic systems have been introduced to enhance depth perception during minimum-access surgery. However, there is no conclusive evidence of benefit, and these systems are more expensive than conventional two-dimensional systems. We undertook a prospective randomised comparison of two-dimensional and three-dimensional imaging in elective laparoscopic cholecystectomy for symptomatic gallstone disease. METHODS: The operations were done by four specialist registrars as part of their higher surgical training. 60 operations were randomised for execution by either two-dimensional or three-dimensional imaging display (30 by each method). The degree of difficulty of the operation was graded by a consultant surgeon on a standard grading system. The primary endpoints were execution time and the errors made during the procedure. The secondary endpoints were subjective assessment of the image quality and adverse effects on the surgeon. FINDINGS: There was no difference between the two-dimensional and three-dimensional display groups in median execution time (3160 [IQR 2735-4335 vs 3100 [2379-3710] s; p = 0.2) or error rate (six vs six). Surgeons reported adverse symptoms immediately after the operations with both systems. The scores for visual strain, headache, and facial discomfort were higher with the three-dimensional system. INTERPRETATION: With the current technology, three-dimensional systems based on sequential imaging show no advantage over two-dimensional systems in the conduct of laparoscopic cholecystectomy.

Adult↗
PubMed1998

Thermal characteristics of a hepatic cryolesion formed in vitro by a 3-mm implantable cryoprobe.

The objective of the investigation was to characterize the hepatic cryolesion formed with an implantable needle (3 x 100 mm) cryoprobe. This was used to produce cryolesions in isolated porcine liver tissue equilibrated to 37 degrees C in a water bath. The shape, size, and temperature zones within the cryolesion and the effect of single versus repeated freeze-thaw cycles on cryolesion size were studied. The final shape of the cryolesion at 15-20 min freezing was cylindrical and its distal hemispherical end extended 8 mm beyond the tip of the cryoprobe. The rate of increase in maximum diameter was logarithmic and decreased from 4.7 mm/min during the first 5 min to 0.4 mm/min during the fourth 5-min period of freezing. By contrast, the rate of increase in volume was linear and ranged from 9.6 to 7.9 ml/min during the corresponding periods. The volume of the hepatic cryolesion after 20 min of continuous freezing was significantly greater than that of the cryolesion formed with 20 min of cumulative freezing interrupted by a 5-min spontaneous thaw. The ultimate temperatures reached and the cooling rates varied in different zones within the cryolesion depending on distances away from and alongside the cryoprobe. Diameter measurements taken in isolation do not reflect the actual growth rate of the cryolesion. Volume measurements define more accurately the amount of tissue frozen and left in situ. Prolonged freezing beyond 20 min did not increase the diameter of the cryolesion. A single continuous freeze produces a larger cryolesion than two freeze-thaw cycles of the same freezing duration.

Animals↗
PubMed1998

Total radiated power, infrared output, and heat generation by cold light sources at the distal end of endoscopes and fiber optic bundle of light cables.

BACKGROUND: Skin burns and ignition of drapes have been reported with the use of cold light sources. The aim of the study was to document the temperature generated by cold light sources and to correlate this with the total radiated power and infrared output. METHODS: The temperature, total radiated power, and infrared output were measured as a function of time at the end of the endoscope (which is inserted into the operative field) and the end of the fiber optic bundle of the light cable (which connects the cable to the light port of the endoscope) using halogen and xenon light sources. RESULTS: The highest temperature recorded at the end of the endoscope was 95 degrees C. The temperature measured at the optical fiber location of the endoscope was higher than at its lens surface (p < 0.0001). At the end of the fiber optic bundle of light cables, the temperature reached 225 degrees C within 15 s. The temperature recorded at the optical fiber location of all endoscopes and light cables studied rose significantly over a period of 10 min to reach its maximum (p <0.0001) and then leveled off for the duration of the study (30 min). The infrared output accounted only for 10% of the total radiated power. CONCLUSIONS: High temperatures are reached by 10 min at the end of fiber optic bundle of light cables and endoscopes with both halogen and xenon light sources. This heat generation is largely due to the radiated power in the visible light spectrum.

Cold Temperature↗
PubMed1998

Computer-controlled endoscopic performance assessment system.

We have devised an advanced computer-controlled system (ADEPT) for the objective evaluation of endoscopic task performance. The system's hardware consists of a dual gimbal mechanism that accepts a variety of 5.0-mm standard endoscopic instruments for manipulation in a precisely mapped and enclosed work space. The target object consists of a sprung base plate incorporating various tasks. It is covered by a sprung perforated transparent top plate that has to be moved and held in the correct position by the operator to gain access to the various tasks. Standard video endoscope equipment provides the visual interface between the operator and the target-instrument field. Different target modules can be used, and the level of task difficulty can be adjusted by varying the manipulation, elevation, and azimuth angles. The system's software is designed to (a) prompt the surgeon with the information necessary to perform the task, (b) collect and collate data on performance during execution of specified tasks, and (c) save the data for future analysis. The system was alpha and beta tested to ensure that all functions operated correctly.

Endoscopy↗
PubMed1998

Chemical composition of smoke produced by high-frequency electrosurgery in a closed gaseous environment. An in vitro study.

BACKGROUND: High-frequency (HF) electrocoagulation and cutting procedures produce smoke by high-temperature pyrolysis of tissues. As distinct from the experience of conventional surgery, electrosurgical smoke is produced in a closed gaseous environment during laparoscopic operations. As a result, toxic chemicals may be absorbed into the circulation. The effects of this absorption are not known. Furthermore, the chemical composition of electrosurgical smoke produced in an anoxic environment may be different from that produced in air. METHODS: Smoke was produced in vitro by HF electrocutting of fresh porcine liver in helium, CO2, and air-saturated closed environments. Smoke samples were collected and analyzed by gas chromatography-mass spectrometry (GC-MS). RESULTS: The chemical constituents of electrosurgical smoke produced in air, CO2, and helium were similar. To date, 21 chemicals, some highly toxic, have been identified in the electrosurgical smoke produced in a closed environment. These consist of hydrocarbons, nitriles, fatty acids, and phenols. CONCLUSIONS: Electrosurgical smoke produced in a closed environment contains several toxic chemicals. The effects of these on cell viability, macrophage, and endothelial cell activation are not known but are being investigated. Meantime, measures to reduce smoke and evacuate it during endoscopic surgery are advisable.

Air Pollutants↗
PubMed1998

Cytotoxicity of electro-surgical smoke produced in an anoxic environment.

BACKGROUND: The effect on cell viability of smoke produced during high-frequency electro-surgery has not been previously reported. The aim of this study was to produce smoke in vitro, in a closed environment similar to that encountered in minimal access surgery, and to test its cytotoxic effects on cultured cells. METHODS: Pig liver was cut repeatedly with an electro-surgical hook knife, and the smoke generated was collected and equilibrated with cell culture medium. MCF-7 human breast carcinoma cells were exposed briefly to various dilutions of this medium and tested for clonogenicity. RESULTS: Electro-surgical smoke produced in a helium environment reduced the clonogenicity of the MCF-7 human breast carcinoma cells in a dose-dependent manner, falling to 30% when the cells were exposed to undiluted medium for 15 minutes. CONCLUSIONS: We conclude that electro-surgical smoke is cytotoxic. The sublethal effects at lower dilutions are currently being investigated.

Anaerobiosis↗
PubMed1998

Ergonomic evaluation of laparoscopic bowel suturing.

BACKGROUND: Ergonomic assessment of the instrument to needle to tissue relationship on efficiency and accuracy of laparoscopic suturing. METHODS: Video records of nine laparoscopic surgeons were analyzed for five technical variables of laparoscopic suturing. Surgeons undertook closure of 60 mm enterotomy using continuous 3/0 seromuscular atraumatic sutures. Subjects attempted to suture 3 to 5 mm from enterotomy edge and at 3 to 5 mm intervals. Vertical/horizontal deviations from desired entry/exit point of suture, execution time, and failure to complete sutures were recorded. RESULTS: Visualization style used by some was significantly more accurate but slower than the nonvisualization style used by others. Needle insertion angle of 80 degrees to 100 degrees gripping the middle and proximal end of needle and holding the needle >90 degrees to instrument axis significantly improved task accuracy. Insertion angle <80 degrees produced three times the failure rate of 80 degrees to 100 degrees. Surgeon's performance was consistent with either suturing style. CONCLUSIONS: Visualization style was slower but more accurate. Optimum conditions for good suturing include 80 degrees to 100 degrees needle insertion angle; holding angle >90 degrees, and gripping point at middle and proximal third of the shaft of the needle. Task accuracy was surgeon dependent.

Colon↗
PubMed1998

Errors enacted during endoscopic surgery--a human reliability analysis.

The aim of the study was to document the nature and incidence of surgical errors enacted during laparoscopic surgery in order to direct future research and surgical training. A modified Human Reliability Analysis (HRA) approach, based on direct observation, was adopted to categorise and record errors encountered during the practice of laparoscopic cholecystectomy. This study confirmed the applicability and usefulness of an observational methodology in the assessment of human error in endoscopic surgical performance. The study identified aspects of the design and usage of instruments, surgical training and the differences between tasks which needed further directed research in order to identify underlying performance shaping factors (PSFs) and so reduce error rates.

Cholecystectomy↗
PubMed1998

Does laparoscopic cardiomyotomy require an antireflux procedure?

BACKGROUND AND STUDY AIMS: There is controversy concerning the need for an antireflux procedure in patients undergoing open or endoscopic cardiomyotomy for achalasia. The addition of an antireflux wrap (partial or total), while preventing reflux, may result in persistence or incomplete relief of dysphagia in patients with total oesophageal aperistalsis. The technique of laparoscopic cardiomyotomy used in Dundee preserves the lateral and posterior attachments of the gastro-oesophageal junction, and was designed to minimize the risk of gastro-oesophageal reflux. PATIENTS AND METHODS: A consecutive series of patients with achalasia (n = 19) were treated by laparoscopic cardiomyotomy using the Dundee technique, which limits the mobilization to the anterior wall of the abdominal and thoracic oesophagus. The patients were followed up prospectively to assess the long-term relief of dysphagia and the postoperative incidence of reflux symptoms, with or without oesophagitis. RESULTS: The follow-up symptoms and assessment of the patients (15-53 months, median 27 months) showed total relief (n = 12) or substantial relief (n = 5) of dysphagia in 89%. On assessment at a median follow-up of 27 months, the number of patients experiencing heartburn after this operation increased from four of 15 to five of 15, and one patient (6.6%) developed endoscopically proved oesophagitis, with a positive oesophageal pH monitoring test. CONCLUSIONS: The routine addition of an antireflux operation is not justified in patients undergoing laparoscopic cardiomyotomy, provided that the lateral and posterior attachment of the oesophagus are kept intact.

Adult↗
PubMed1998

Task performance in endoscopic surgery is influenced by location of the image display.

OBJECTIVE: To investigate the influence of image display location on endoscopic task performance in endoscopic surgery. SUMMARY BACKGROUND DATA: The image display system is the only visual interface between the surgeon or interventionist and the operative field. Several factors influence the correct perceptual processing and endoscopic manipulation from images. One of these is location of the image display with respect to the surgeon and to the operative site. The present study was conducted to investigate whether endoscopic task performance improves under two conditions: when the surgeon-to-monitor visual axis is aligned with the forearm-instrument motor axis and when the image display is close to the operator's manipulation workspace. METHODS: An endoscopic task (tying an intracorporeal surgeon's knot) was performed under standardized conditions except for varying monitor locations. These altered the direction of view--in front of, to the left, and to the right of the operator's head and hands. In each of these view directions, the monitor was placed at the surgeon's eye level and lower down, at the level of the operator's hands. The outcome measures were the execution time, knot quality score and performance quality score. RESULTS: Task performance was better with frontal view direction: execution time was shorter (p < 0.0001) and the performance score was higher (p < 0.005) than with side viewing, with no significant difference between right and left viewing directions. With frontal view direction, hand-level "gaze-down" viewing resulted in a shorter execution time (p < 0.01) and a higher performance score (p < 0.01) than eye-level viewing. CONCLUSIONS: Task performance improves when the image display is placed in front of the operator, at a level below the head and close to the hands.

Clinical Competence↗
PubMed1998

Percutaneous endoscopic external ring hernioplasty using Dundee inguinal canal retractor.

The percutaneous endoscopic external ring (PEER) hernioplasty is a novel technique that uses a minimal access approach to the inguinal canal by the anterior route and reproduces the conventional open tension-free mesh repair. The procedure consists of two stages: an open phase through a 2.5-cm incision over the external ring followed by an endoscopic repair of the defect. During the open stage, the spermatic cord is mobilized from the external ring, blunt finger dissection of the inguinal canal is used to create a space beneath the external oblique aponeurosis, and the hernial sac is dissected down to level of the preperitoneal fascia. The second endoscopic stage is performed after insertion of a telescope-mounted retractor through the external ring. The posterior wall of the inguinal canal is visualized and the hernial defect repaired by a tension-free mesh repair (Lichtenstein onlay mesh repair or mesh plug repair). The procedure provides an anatomic approach that is familiar to general surgeons. In a pilot study, the authors have established that the PEER hernioplasty is an easily learned, safe, and cost-effective operation that offers the benefits of minimal access surgery in terms of patient recovery and early return to work, and can be performed as a day case under local or regional anesthesia.

Adult↗