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Biomedical subjects

D C O'Sullivan

Publications and source records attributed to D C O'Sullivan.

At least 19 recordsLinked to original sources
PubMed1998

Factors involved in gas embolism after laparoscopic injury to inferior vena cava.

This study evaluated the incidence and factors involved in the occurrence of gas embolism after laparoscopic injuries. A 5-MHz transesophageal echocardiographic (TEE) probe was placed in 11 anesthetized pigs and used to examine the right cardiac chambers and pulmonary artery. A calibrated carbon dioxide analyzer continuously measured end-tidal carbon dioxide (ETCO2). The ventilatory settings were adjusted to achieve a baseline ETCO2 between 25 and 28 mm Hg. A blinded dose-response curve for TEE and ETCO2 measurements were created by injecting 0.0007 to 1.5 mL/kg of CO2 gas intravenously. Venotomies (N = 22) were created laparoscopically in the inferior vena cava (IVC) of the study animals. All TEE images were videotaped and correlated with laparoscopic events. Embolic episodes were classified by comparison with images recorded during the bolus studies. A variety of methods for obtaining hemostasis and repairing the venotomies were evaluated and their effects on gas embolism were studied. No emboli were noted when the venotomies were bleeding freely, the hole was directly occluded, or the proximal IVC was compressed. Marked embolism was seen with distal IVC occlusion or when there had been significant blood loss. In this situation, manipulation of the hole and higher intraperitoneal pressures led to higher degrees of embolization. No emboli were seen in an open control group except after significant bleeding. The TEE is the most sensitive method of detecting gas emboli; however, the majority of episodes are not clinically significant. Embolism of CO2 occurs when central venous pressure is decreased by blood loss or distal compression. When significant venous bleeding occurs, intravascular volume should be maintained and the bleeding site should be directly occluded.

Animals↗
PubMed1997

Teleradiology in urology: comparison of digital image quality with original radiographic films to detect urinary calculi.

PURPOSE: Teleradiology systems are now being evaluated as a mechanism to provide rapid, accurate and cost-effective diagnostic radiographs to off-site physicians. Little data are available on the role and safety of teleradiology in urology. To address these issues a personal computer based system was developed to assess the diagnostic accuracy and ease of use of transmitted digital images when evaluating for urinary calculi. MATERIALS AND METHODS: A total of 100 plain abdominal scout films from excretory urograms performed during acute urological referrals was digitized on a laser scanner. The 10 megabyte files were transferred over public telephone lines and written to compact disks. The images were viewed on a 1280 x 1640 resolution monitor using "Imager-3D" software run on a 133 MHz. pentium personal computer with 32 megabytes of random access memory. Two faculty urologists and 2 urology fellows each looked at 50 original radiographs and 50 digital images. Diagnostic interpretations of the presence and location of calculi were recorded, and confidence in the diagnosis, assessment of image quality and diagnostic difficulty were scored using a numerical scale. RESULTS: The accuracy for all readers was 86.5% for plain radiographs and 81.5% for digital images (p >0.2). There was no statistical difference between faculty and fellows. Diagnostic accuracy did not differ between plain films and screen images when the results were assessed with respect to image quality, diagnostic difficulty or the reader confidence in the diagnosis (p >0.1). Compared to plain films, more screen images were classified as lower image quality (60 versus 40%) and the diagnostic confidence was lower (low and medium grade 50 versus 35%), although this did not interfere with diagnostic accuracy. CONCLUSIONS: These data imply that a high quality affordable teleradiology system is effective and accurate compared to plain films for assessing urinary calculi.

Humans↗
PubMed1996

Circumcision: how do urologists do it?

OBJECTIVE: To determine the range of surgical techniques, analgesic practice, post-operative care and follow-up procedures used in the circumcision of children by urologists in the United Kingdom, and to suggest changes which would improve patient care and medical training in the relatively simple procedure of circumcision. MATERIALS AND METHODS: In 1994, all consultant urologists in the United Kingdom were sent detailed questionnaires asking about their practices in the circumcision of children. RESULTS: Of 308 urologists, 61% replied; of these, 55% use the sleeve-resection technique and 39% the free-hand method, and 57% use diathermy, half of which is bipolar. There is wide variation in the type of post-operative analgesia; 95% use an initial dressing but few recommend any subsequent dressing, 70% perform all circumcisions as day cases and 48% review patients in the clinic. There is significant concern that circumcision is not taught adequately to junior surgeons. CONCLUSION: The sleeve technique of resection should be more widely used. Analgesic practice could be improved with greater use of regional anaesthetics. Most urologists promote no specific care after discharge. There is probably a place for increasing the use of alternative procedures to circumcision.

Analgesia↗
PubMed1995

Should Stamey colposuspension be our primary surgery for stress incontinence?

OBJECTIVE: To evaluate the outcome of the Stamey procedure for stress incontinence and to decide if it is an acceptable first-line option for the treatment of patients. PATIENTS AND METHODS: Between June 1987 and March 1993 67 women had Stamey bladder neck suspension carried out for the treatment of stress incontinence. In September 1993 all patients received a detailed questionnaire to ascertain their present status. RESULTS: Immediately after surgery 70% of patients were dry and 15% were much improved. At 6 months 56% of patients were dry and 21% were much improved. More than 1 year following surgery, of 58 patients responding only 31% were dry and 28% were much improved. More than 5 years after surgery only 18% of the 28 women responding were dry. The factors which were significantly associated with failure were obesity (P < 0.005) and the number of pads used per day (P < 0.05). Previous surgery may also be an important factor. CONCLUSION: The Stamey vesical neck suspension has a good early success rate but the results in the longer term are not acceptable. This operation should not be used as a first-line treatment for stress incontinence and should be reserved for specific patient subgroups.

Adult↗
PubMed1994

Prosthetic bladder: in vivo studies on an active negative-pressure-driven device.

Active alloplastic bladders were implanted into four dogs after cystectomy and were well tolerated. The prosthesis created a vacuum of -90 cm. H2O in the upper tracts, which gradually decreased until the bladder filled. Renal function was maintained as long as the prostheses worked effectively. Hydronephrosis developed and renal function deteriorated if the bladder was not emptied, even though the leak pressure was only 3 to 5 cm. H2O. Both resolved when active bladder function was restored. Pressures in the ureter were measured percutaneously, at flow rates up to 15 ml. per minute (900 ml. per hour). At 15 ml. per minute, the pressure only reached a maximum of 16 cm. H2O. Encrustation did not occur even in the presence of infection. The results achieved with this negative pressure bladder prosthesis, which is emptied actively, are very promising and should provide the impetus for increased research in this field of urology.

Animals↗
PubMed1994

Transplant nephrectomy over 20 years: factors involved in associated morbidity and mortality.

Of 1,048 renal transplants performed between 1971 and 1990, transplant nephrectomy was performed in 86 (8.2%). Mean patient age was 33 years (range 3.8 to 66.5). Postoperative complications occurred in 60% of the patients, including wound infection in 20% and major hemorrhage in 4 patients. The external iliac artery was ligated in 4 patients. The incidence and severity of the complications were greater in patients with acute rejection. Four patients died: 1 of ischemic bowel and metastatic carcinoma, 1 of pulmonary embolism, and 2 of sepsis and disseminated intravascular coagulation. The nephrectomy rate increased significantly (p < 0.005) when cyclosporine A was initially introduced. Added care is necessary when new immunosuppressants are used. The majority of our failed transplants were left in situ without compromising overall patient well-being.

Adolescent↗
PubMed1994

Ureteric stricture formation following ureteric instrumentation in patients with a nephrostomy drain in place.

OBJECTIVE: To determine what effect the presence of a nephrostomy, left on free drainage, might have on the rate of occurrence of ureteric strictures after ureteric instrumentation. PATIENTS AND METHODS: Eighteen patients were identified in this unit who had had ureteric instrumentation while a nephrostomy was in place. RESULTS: Eight of 11 patients in whom the nephrostomy was left open developed ureteric strictures. None of seven patients in whom the lumen was maintained by stenting and/or clamping of the nephrostomy developed strictures. The strictures needed dilatation and stenting in seven patients and the ureter had to be reimplanted in the other. CONCLUSION: In patients in whom a nephrostomy is in place, the opening should be occluded after ureteric instrumentation or a stent should be inserted if it is to be left on free drainage.

Adult↗
PubMed1993

Subcutaneous port for longterm access and administration of topical chemotherapy to the upper urinary tract.

Fourteen silicone pigtail catheters were inserted into the renal pelves of ten 25 kg. pigs. These catheters were connected to injection ports implanted in the flank. Each animal received 15 mg. of thiotepa, into one port, weekly for 8 weeks. These were well tolerated. Percutaneous radiography and histological examination showed effective distribution of thiotepa throughout the upper urinary tract. Microscopic changes included cytoplasmic vacuolation, cystic changes and denudation of the mucosa. There was edema and chronic inflammatory infiltrate in the submucosa. This method of access to the upper tracts should be considered for long-term recurrent treatment of upper tract superficial transitional cell carcinoma.

Administration, Topical↗
PubMed1992

Artificial bladder replacement: a new design concept [see comment].

An effectively functioning artificial bladder would be useful after cystectomy because of the ease of insertion and the availability to all patients. In this report, we describe a new design concept based on negative pressure drainage of the kidneys and active voiding, and we present the results of testing this device. Although previous prosthetic bladders have had difficulties with renal failure from hydronephrosis, infection from retention of urine, and encrustation of the luminal surface, the current artificial complete bladder system addresses these problems.

Humans↗
PubMed1992

Compensatory hypertrophy effectively assesses the degree of impaired renal function in unilateral renal disease.

A series of 66 children with unilateral renal disease and normal total renal function were reviewed with the aim of determining whether clinically detectable compensatory hypertrophy indicated severe contralateral renal impairment. The proportion of total renal function that was contributed by each kidney was determined using isotope renography (99mTc-DTPA for 46 children, 99mTc-DMSA for 20). Kidney length was measured from plain abdominal radiographs or intravenous urograms and hypertrophy was expressed as the renal size index (RSI). Of 37 kidneys with a RSI greater than 2 standard deviations from the mean, 36 had less than 15% of total function in the contralateral diseased kidney. Kidneys with less than 10 or 15% of total renal function could be selected with 97 or 80% sensitivity and 84 or 97% specificity, respectively, using the same RSI selection level.

Adolescent↗
PubMed1992

Acute urinary retention. Comparison of suprapubic and urethral catheterisation.

A total of 86 consecutive patients who presented to the accident and emergency department with acute urinary retention due to prostatomegaly required catheterisation; 56 received suprapubic catheters and 30 were catheterised urethrally. Both groups were followed up for 3 years. Of the 30 patients catheterised urethrally, 12 (40%) developed urinary tract infections compared with 10 (18%) urinary tract infections in the 56 patients catheterised suprapubically. Five patients (17%) in the urethral group developed urethral strictures with no strictures in the suprapubic group. Two patients catheterised urethrally developed epididymo-orchitis and 1 developed septicaemia. None of the patients with suprapubic catheters developed these complications. Furthermore, 16 patients catheterised suprapubically underwent successful trial clamping of their catheter, whereas 7 patients required recatheterisation following removal of their urethral catheters. We recommend that the use of suprapubic catheters should become the preferred initial treatment for acute urinary retention.

Acute Disease↗
PubMed1992

Effect of external beam radiotherapy on prostatic carcinoma DNA content as measured by static image cytometry.

Static image cytometry was used to study the effect of radiotherapy on the DNA content of prostatic carcinoma. Feulgen-stained specimens from 50 patients before and after radiotherapy were examined. The DNA index increased significantly after treatment (p less than 0.03), and it occurred equally in those with low (less than 1.5) and high (greater than or equal to 1.5) indices. The level of the initial DNA index was significantly related to the rate of symptomatic progression (p less than 0.05). The initial change in and final DNA indices were not related to survival however. There was a significant increase in Gleason score (p = 0.001) and histological grade (p = 0.01) after irradiation and, when taken individually, the degree of change was related to survival in both, p = 0.05 and 0.004, respectively. As Gleason score, Mayo grade and clinical stage were not independent variables; none of them was related to survival when corrected for the other factors. Thus, DNA content or ploidy, as well as Mayo grade and Gleason score, increases in recurrent tumor after radiotherapy. This may be of importance when considering what treatment to use and how intensively the patients should be followed up.

Actuarial Analysis↗
PubMed1991

Particle shedding and migration from silicone genitourinary prosthetic devices.

Of 26 patients undergoing revision of genitourinary prostheses the surrounding reactive fibrous capsule was biopsied in 25 and the draining lymph nodes also were biopsied in 4. The prostheses included 16 inflatable and 14 flexible penile devices, and 10 artificial urinary sphincters. Tissue was examined by light and transmission electron microscopy. X-ray microanalysis was done on intracellular and extracellular foreign material from each specimen. Silicone was found in 18 of the 25 periprosthetic specimens and in all 4 lymph nodes. Foreign body granulomas were identified in 14 of these 29 specimens. Examination of new and explanted versions of each prosthesis by scanning electron microscopy revealed free particles of silicone or silicates on the surface of most devices. Pitting and microfissuring were seen on a few of the new devices and on nearly all of the used ones. Thus, genitourinary prostheses shed silicone particles that can be found in the fibrous capsule and draining lymph nodes.

Adolescent↗
PubMed1991

Artificial bladder and the use of the artificial sphincter.

Gradually, the lifestyle that can be offered to a patient who requires a cystectomy or has a small incontinent bladder is being improved. It is possible to combine sphincter placement with cystoplasty and neobladder formation if the surgery is carried out with care. Further development of the sphincters is required before their use around bowel segments will provide consistently safe results. Concurrently, development of the totally artificial bladder is progressing toward an ideal of a system that is biocompatible and preserves renal function.

Equipment Design↗
PubMed1983

Suprapubic prostatectomy--combined technique.

Three hundred and fifty-one consecutive prostatectomies have been carried out using a combined suprapubic approach for the enucleation of the adenoma and a transurethral approach to control bleeding. Removal of any residual tissue in the prostatic fossa and removal of a wedge from the bladder neck are done with the resectoscope. The procedure is reserved for larger adenomas not suitable for transurethral resection.

Aged↗