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Biomedical subjects

I F Hawkins

Publications and source records attributed to I F Hawkins.

At least 55 records · Page 3Linked to original sources
PubMed1989

The use of carbon dioxide gas to displace flowing blood during angioscopy.

Carbon dioxide (CO2) gas is a safe and effective arterial contrast agent that images arteries by displacing blood. The use of CO2 gas to displace blood during angioscopy may improve intraoperative angioscopy and allow percutaneous angioscopy. To study this, 46 angioscopic evaluations in the femoral arteries of four dogs were done without inflow occlusion. The ability of CO2 gas to clear the flowing blood was compared to a high-pressure infusion of saline solution. Carbon dioxide gas successfully displaced flowing blood in 20 of 25 evaluations (80%) as compared to three of 21 evaluations (14%) with infusion of saline solution (p less than 0.0001). After the CO2 gas infusion was stopped, the image remained clear for 9 +/- 1 seconds. When saline was used, the image was clear only as long as the infusion was continued. The quality of clear images for the two media were similar through the eyepiece of the angioscope, but images observed through the motion picture camera had better contrast and depth of field in CO2 gas. The use of a CO2 gas infusion can clear the field of flowing blood without the risk of volume overloading and potentially allow performance of a successful percutaneous angioscopy.

Animals↗
PubMed1988

Extracorporeal shock-wave lithotripsy (ESWL). II. In vivo canine results of blast path treatment of human gallstones.

To evaluate the role of ESWL in vivo for the treatment of human gallstones positioned on the blast path, a canine model was developed to determine the efficacy of stone fragmentation and the subsequent histopathological injury that occurs as a result of this therapeutic technique. Twenty-four 16- to 20-kg mongrel dogs were divided into five groups: I: ESWL without stone, autopsy at 48 hr (N = 6); II: ESWL with stone (mean diameter 16.8 mm, range = 14-19 mm), autopsy at 48 hr (N = 10); III: ESWL without stone, autopsy at 41-46 days (N = 6); IV: ESWL without stone, autopsy immediately after ESWL (N = 1); V: No ESWL or stone, autopsy 2 hr after anesthesia induction (N = 1). A human gallstone (96% cholesterol) was inserted by cholecystotomy (N = 10) in Group II only. All groups (N = 24) had operative placement of a 6.5 Fr accordion catheter into the gallbladder for radiographic visualization. For each blast path treatment, 2000 discharges were delivered at 18-24 kV. Histopathologically, the Group V gallbladder served as a control. Groups I, II, and IV revealed mild subacute injury; dog gallbladders in Group III showed regression of these changes. Total surface area (TSA) of Group II stones increased from a pre-ESWL mean of 6.60 +/- 0.0.84 cm2 to 53.84 +/- 26.8 cm2 post-ESWL (P less than 0.001). Cumulative post-ESWL fragment sizes for particles in less than or equal to 2-, less than or equal to 3-, less than or equal to 5-, less than 10- and greater than or equal to 10-mm categories represented 32.9, 41.6, 49.4, 74.3, and 100% of pretreatment stone weight, respectively. These data indicate that human gallstones can be fractured to a variable degree when treated on the ESWL blast path and that TSA increased significantly. Gallbladder histopathologic changes appear to be reversible by 41-46 days post-ESWL.

Animals↗
PubMed1988

Directional needle for antegrade guide wire placement with vertical arterial puncture.

A directional needle with a closed pencil-point tip and a distal side hole was developed to permit antegrade guide wire placement by way of a 90 degrees puncture angle. It has been used in over 25 patients without technical difficulties or complications. It has been very effective for catheterization of the superficial femoral artery for angioplasty, diagnostic studies, and chemotherapy infusion, providing easy antegrade access in patients in whom the traditional antegrade approach may be difficult.

Catheterization, Peripheral↗
PubMed1988

Retractable-barb needle for breast lesion localization: use in 60 cases.

A needle system with a retractable barb was developed for localization of nonpalpable breast lesions. The system can be repositioned without major adjustments and strongly anchors to breast tissue, eliminating failure due to dislodgment or transection of the localizing wire. Its use may necessitate fewer confirmatory radiographs, resulting in decreased radiation exposure. In addition, the needle can be retracted during surgery, to ease extraction of the specimen.

Biopsy, Needle↗
PubMed1987

The ureteral access system: a review of the immediate results in 43 cases.

The ureteral access set was used 43 times during an 18-month period between 1984 and 1985. Stones lodged throughout the ureter and in the renal pelvis were extracted with a success rate of 51 per cent. Of the upper tract strictures 92 per cent were dilated successfully. Filling defects were diagnosed in 88 per cent of the cases. Foreign bodies were retrieved, Double-J stents were placed and biopsies were successful in each case. Ureteral perforation in 28 per cent of the cases was caused by the dilator in 8 of 12 (19 per cent over-all). The technique and short-term results are discussed. Long-term followup data are not yet available.

Catheterization↗
PubMed1987

The treatment of acute cholangitis. Percutaneous transhepatic biliary drainage before definitive therapy.

Forty-two patients with acute cholangitis, as evidenced by fever (95%), jaundice (86%), and right upper quadrant pain (67%), were treated with fluid and electrolyte resuscitation, broad spectrum antibiotic coverage, and initial percutaneous transhepatic biliary drainage (PTD). Despite a 17% incidence of nondilated ductal systems, drainage was established in all patients using a 22-gauge "skinny" needle and "accordion" catheter. No attempt was made at definitive cholangiogram; only 1-2 mL of contrast were injected to confirm placement of the catheter. Sepsis began to resolve in all patients within 24 hours of PTD, after which definitive cholangiogram was performed. PTD was accompanied by a 7% (3/42) complication rate, none of which contributed to subsequent morbidity and mortality. Two patients in severe septic shock had PTD but died within 8 hours of admission, constituting a 5% mortality rate. Definitive therapy after resolution of sepsis included: surgical (16 patients), internal/external drainage (14 patients), balloon dilatation (10 patients), mono-octanoin infusion (1 patient), and ampullary dilatation (1 patient). The surgical morbidity rate was 18%. There was no mortality. PTD is effective in providing decompression as initial therapy for acute cholangitis with minimal morbidity. Accurate diagnosis provided by the definitive cholangiogram obviates the need for multiple surgical procedures. PTD provides a portal to the biliary tract for alternative procedures (i.e., internal/external drainage, balloon dilatation), especially in patients with medical contraindications to surgery.

Acute Disease↗
PubMed1987

Localization and resection of gastrinomas in Zollinger-Ellison syndrome.

From 1971-1986, 24 patients were diagnosed as having Zollinger-Ellison syndrome (ZES) and 22 patients had laparotomy. Of this group, gross tumor was identified in 15 of 22 patients. Ten of 15 patients had resection of their gastrinomas with the specific aim of curing the disease. This group had responded favorably to either cimetidine or ranitidine before operation. Preoperative transhepatic portal venous sampling (PVS) with gastrin determinations was performed in six patients; three patients had this procedure twice. The tumor was correctly localized by PVS in five of six patients. In four of six patients, the tumor was easily found at surgery. In two of six patients (33%) PVS was vital to intraoperative decisions. Criteria for biochemical cure are normal periodic fasting gastrin and secretin infusion tests. Of the 10 patients who had resection for potential cure, two patients failed within 48 hours of surgery on the basis of an elevated fasting serum gastrin level in one patient and a positive secretin infusion test in the other patient. Eight patients were considered cured with follow-up from 6 months through 15 years. Of the eight cured patients, the tumors were located as follows: four were extraintestinal and extrapancreatic, four were in the duodenal wall, one patient had a tumor located in the uncinate process of the pancreas, and one tumor was located in a lymph node along the lesser curve of the stomach. Two patients had mobilization of the pancreas and duodenum for a "blind" pancreatoduodenectomy based on preoperative PVS (2 procedures each patient). In one patient a 3-mm gastrinoma was enucleated from the posterior uncinate process. The second patient had pancreatoduodenectomy with findings of two duodenal wall gastrinomas. Both patients remained cured of ZES beyond 2 years. It is concluded that PVS does indeed locate some tumors before operation, even those not easily found at surgery. ZES can be cured by an aggressive approach combining preoperative tumor localization and tumor resection. Of the eight patients biochemically and perhaps biologically cured, follow-up was greater than four years in five patients, greater than two years in two patients, and beyond six months in one patient.

Duodenal Neoplasms↗
PubMed1987

Retrograde percutaneous nephrostomy.

The percutaneous approach has become an accepted procedure for the removal of kidney stones in the urinary tract. Developed initially from our method of transvenous punch biopsy and transvenous cholangiography, the "inside-out" retrograde nephrostomy technique involves either cystoscopic or fluoroscopic placement of a 9 or 10 French catheter into a selected minor calix, through which a fine 21-gauge needle passes and exists the skin. The tract is then dilated over the needle. Used in over 200 cases without any complications directly attributable to the nephrostomy, the retrograde approach is safer, more reliable, and less time consuming than the previous standard antegrade approach, particularly in the nondilated pelvicalyceal system. Also presented are several new modifications to the original procedure and further technical considerations for operators.

Humans↗
PubMed1986

Retrievable Gianturco-coil introducer.

A new delivery system for placement of Gianturco coils has been devised that permits retrieval of the coil if malposition occurs. The delivery system itself consists of a very fine coaxial cannula that will cut the monofilament once the coil is properly placed. It has been successfully used on three patients in whom a total of 48 coils were employed to occlude great vein of Galen aneurysms. The system is applicable for routine coil embolization but has particular application in treating high-flow vascular lesions (arteriovenous fistulas or malformations).

Embolization, Therapeutic↗
PubMed1985

Evaluation of percutaneous transhepatic balloon dilatation of benign biliary strictures in high-risk patients.

During the period from 1979 through 1984, 17 patients with benign biliary strictures underwent percutaneous transhepatic balloon dilatation. All patients presented with either hyperbilirubinemia and acute cholangitis, a history of intermittent chills and fever, or both. Balloon dilatation was most successful in those patients with intrahepatic strictures, sclerosing cholangitis, strictured biliary enteric anastomoses, and distal common bile duct strictures with retained calculi. Two patients with postsurgical common bile duct injury had treatment failure 3 and 18 months after dilatation and subsequently underwent elective hepaticojejunostomy. Although our longest treatment success is now more than 4 1/2 years in an 83 year old woman who is 15 years posthepaticojejunostomy, the mean follow-up of the entire group has only been 2 years. On the basis of our early experience and that of others, we now recommend an initial attempt at balloon dilatation in most patients with postsurgical benign biliary strictures. Further technical advances and longer follow-up in present and future series may certainly broaden the appeal of this nonoperative procedure.

Adult↗
PubMed1985

Preoperative angioinfarction of localized renal cell carcinoma using absolute ethanol.

A total of 25 patients with renal cell carcinoma underwent angioinfarction of the tumor using absolute ethanol. An average of 15 ml. absolute ethanol was injected into the main renal artery through a balloon occlusion catheter. Complete cessation of renal arterial flow could be demonstrated in all cases. The post-embolization syndrome of pain, nausea, vomiting, hypertension and fever was minimal compared to other methods of renal artery occlusion. Of the patients 21 underwent post-infarction transabdominal radical nephrectomy without intraoperative or postoperative complications attributable to the injection of absolute ethanol. No damage to extrarenal tissue was noted at operation. Subsequent surgical dissection was facilitated, particularly in cases of large tumors when control of the renal pedicle often is difficult. Median blood loss was 725 ml. In light of recent reports concerning the benefit of angioinfarction and nephrectomy in metastatic disease a similar approach may be applicable to localized disease. This pilot study shows the safety of preoperative angioinfarction with absolute ethanol and may be used as a reference for future randomized prospective studies comparing angioinfarction and nephrectomy to nephrectomy alone for localized renal cell carcinoma.

Adult↗