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Biomedical subjects

J P Fletcher

Publications and source records attributed to J P Fletcher.

17 recordsLinked to original sources
PubMed1992

Deep vein thrombosis prophylaxis: a survey of current practice in Australia and New Zealand.

A survey of current practice for deep vein thrombosis (DVT) prophylaxis was undertaken in Australia and New Zealand. The most common indications for prophylaxis were a history of thrombo-embolism, the type and length of surgery and obesity. Prophylaxis was used in 65% of patients having hip surgery and in 39% undergoing knee surgery. In general surgery the corresponding rate was around 67% for colorectal surgery, hepatobiliary, upper gastrointestinal and major abdominal vascular surgery. Apart from open-heart cardiothoracic surgery (66%), use in other specialties was less than 50%. Physical methods (anti-embolism stockings, calf stimulation and calf compression devices) were most commonly used for prophylaxis (46%) with heparin being used by 40%. The main side effect reported with heparin was bleeding (18%). The estimated incidence of DVT and pulmonary embolus (PE) was 2.8 and 0.4% for general surgery, 2.7 and 0.7% for orthopaedic surgery and 6.6 and 1.3% for hip surgery. Intravenous heparin followed by oral anticoagulants was the most commonly used treatment for established DVT and nearly all respondents used intravenous heparin and oral anticoagulants for treatment of PE. Venography was the favoured objective test for diagnosing DVT. The principal reason for considering a change in prophylactic policy was the potential availability of an agent with increased efficacy and a reduced incidence of haemorrhagic complications.

Anticoagulants↗
PubMed1992

Vascular trauma.

An arterial injury causes either major haemorrhage with hypovolaemia and shock or ischaemia in the distribution of the damaged vessel. Initial management consists of establishment of an airway and haemodynamic stabilisation. If there is persisting hypotension because of continuing bleeding, further resuscitation is carried out in the operating room. A rapid systematic examination is performed with a thorough evaluation of motor and sensory function, as vascular injuries are often accompanied by nerve injuries, which should be well defined prior to any attempts at vascular repair. Arteriography, if available promptly, is useful in stable patients. It allows assessment of the extent of injury and of distal vessels and may prevent unnecessary exploration of neck and extremity injuries. However, it should not delay the vascular repair beyond six hours from the time of injury. It is useful if the site of injury is unclear, the trajectory of a missile is unknown or there are multiple pellet injuries but it is unnecessary if there is an obvious vascular injury. It is helpful to have facilities available for intra-operative arteriography. Repair of arterial injury is performed whenever possible. Prolonged ischaemia, beyond six to eight hours, causes irreversible nerve damage and will lead to an unsatisfactory result, even if re-vascularisation is successful. The principle of proximal and distal control and adequate debridement of damaged artery and surrounding tissue must be adhered to. The type of repair depends on the nature and extent of the arterial injury and includes lateral repair, end-to-end anastomosis and vein graft interposition.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1991

Infection of vascular prostheses.

Graft infection occurred in 11 of 322 patients (3.4%) who had insertion of a vascular prosthesis for peripheral vascular disease during a 4-year period. The groin was the most common site of infection and multiple resistant Staphylococcus aureus (MRSA) was the most common organism responsible. Six of 7 MRSA infections occurred following a procedure involving a previously placed graft and/or a groin incision. Prophylactic antibiotics effective against MRSA are recommended for patients having a revisional procedure, especially involving the groin.

Bacterial Infections↗
PubMed1991

Rifampicin impregnation of a protein-sealed Dacron graft: an infection-resistant prosthetic vascular graft.

A gelatin-sealed knitted Dacron vascular graft was prepared by passive impregnation with rifampicin and implanted in the common carotid artery of 10 merino sheep. Another 10 merino sheep had an untreated graft inserted. The graft was topically inoculated with 1 mL of 10(8) colony forming units per mL of Staphylococcus aureus before wound closure. The grafts were harvested at 3 weeks and cultured. All untreated grafts and surrounding tissues became infected. One of the 10 grafts treated with rifampicin became infected (P = 0.0002) and 4 sheep with rifampicin-treated grafts had surrounding tissue infection. No bacteria cultured from the rifampicin-treated sheep developed resistance to rifampicin.

Animals↗
PubMed1990

Ultrasound diagnosis of lower limb deep venous thrombosis.

Venous ultrasound imaging was compared with ascending contrast venography for the diagnosis of suspected deep vein thrombosis (DVT) in the femoral, popliteal and calf vein segments of 44 limbs in 44 patients. One femoral and one calf vein segment could not be imaged (1.5% of the segments examined), but during the same period venography failed in six patients because of an inability to cannulate a swollen limb. Ultrasound imaging compared with venography as a means of diagnosing DVT showed an overall sensitivity of 95% and a specificity of 92%. The sensitivity and specificity of ultrasound imaging for the diagnosis of both femoral and popliteal vein thromboses were 100% and 97%, respectively, and for calf vein thrombosis were 85% and 83%, respectively. This study supports the recommendation that ultrasound imaging is now the investigation of choice for the diagnosis of DVT provided that the scan is performed by an experienced vascular technologist. Ultrasound imaging may also define other pathological conditions presenting in the differential diagnosis of DVT, such as superficial thrombophlebitis and Baker's cyst.

Adult↗
PubMed1990

Establishment of a vascular graft infection model in the sheep carotid artery.

A study was performed to assess whether a model of vascular graft infection could be established in sheep carotid artery. Either a protein sealed Dacron or a polytetrafluoroethylene (PTFE) graft was used in 22 sheep while a control operation was performed on 4 animals. Staphylococcus aureus in concentrations of 10(2), 10(4), 10(6) or 10(8) colony-forming units (CFU) was inoculated into the wound before closure. No infection occurred with an inoculum of 10(2). The lowest concentration of organism producing infection was 10(4) for PTFE, 10(6) for Dacron and 10(8) for controls. Six of eleven Dacron grafts and seven of ten PTFE grafts became infected. The sheep carotid artery has proven a satisfactory model for studies of vascular graft infection.

Animals↗
PubMed1990

Changes in body protein composition following aortic reconstruction.

Major surgery initiates a stress response due to the body's neuroendocrine reaction which leads to a breakdown of muscle protein with an increased urinary nitrogen excretion and a negative nitrogen balance. In vivo neutron activation analysis (IVNAA) is a technique which measures total body nitrogen. A total of 23 IVNAA studies were performed in six patients having aortic reconstruction to assess the effect of this major operation on body nitrogen and to determine the time required for a return to the pre-operative state. Aortic surgery caused a mean decrease of 2.9% in bodyweight (from a mean of 65.4 kg to 63.5 kg) but a much greater decrease of 9.9% in total body nitrogen (from a mean of 1778 g to 1602 g). Only two of six patients had recovered to pre-operative values by the end of the study period which extended for a mean of 92 days.

Aged↗
PubMed1989

Early experiences with laser-assisted thermal angioplasty for peripheral vascular disease.

Laser-assisted angioplasty has been used on 47 occasions in 45 patients for the management of atherosclerosis of the superficial femoral and proximal popliteal arteries. Twenty-four procedures were performed to treat disabling intermittent claudication and 23 procedures were performed for a "threatened limb" (rest pain, ischaemic ulceration or digital gangrene). Technical success was achieved in 40 (85%) cases; the mean length of occluded segment was 7.7 cm. The presence of heavily calcified occlusions contributed significantly (P less than 0.001) to technical failure. In 28 (70%) of the successfully treated cases, the recanalized arteries were patent at one month and in 21 (53%) cases they have remained patent during the follow-up period. In five of nine cases with a nine-month follow-up, the arteries still were patent. The mean length of the occluded segments that were treated initially was 7.1 cm in those that remained patent compared with 8.2 cm in those that reoccluded. Thirty-six (77%) patients were discharged from hospital on the day after the procedure. Laser-assisted angioplasty is a promising new technique that is applied best to short-segment, non-calcified occlusions and should reduce the requirement for femoropopliteal arterial bypass surgery.

Adult↗
PubMed1989

Percutaneous feeding gastrostomy.

Percutaneous endoscopic gastrotomy tubes have been inserted in 50 patients with no mortality and minimal morbidity. The principal indications for their insertion were an inability to swallow (39 patients), a need for nutritional support (eight patients) and venting (three patients). The most common complication was peristomal wound infection (14 patients), the incidence of which was reduced significantly by the use of single-dose prophylactic antibiotic therapy. Percutaneous gastrostomies provide adequate nutrition with minimal morbidity in an acceptable way to both patients and those who care for them.

Adolescent↗
PubMed1989

A 2 year experience of a nutritional support service: prospective study of 229 non-intensive care patients receiving parenteral nutrition.

During a 2 year period, 229 non-intensive care patients received total parenteral nutrition (TPN) for a mean of 23.2 days. Nutritional parameters of weight, triceps skin-fold thickness (TSF), mid-arm muscle circumference (MAMC), total lymphocyte count (TLC), serum albumin and serum transferrin were measured prior to commencement of TPN and then at weekly intervals. All parameters showed an upward trend during the period of TPN. This was small and not statistically significant for weight, TSF, MAMC and albumin; the trends were greater and statistically significant for transferrin (P = 0.001) and TLC (P = 0.002). In contrast, in the 14.4% of patients who died, albumin, transferrin and TLC all fell. Patients who died had a significantly lower initial albumin (P = 0.05), transferrin (P = 0.04) and TLC (P = 0.04). The last values obtained in patients who died were very significantly lower for albumin (P less than 0.001), transferrin (P less than 0.001) and TLC (P = 0.003). Single-lumen tunnelled subclavian catheters had a significantly lower incidence of catheter sepsis (4.8%) compared with double-lumen (17.4%) and triple-lumen (13.7%) catheters (P = 0.01). There was also a greater incidence of mechanical and thrombotic complications with multiple-lumen catheters compared with single-lumen catheters (P = 0.02). This study shows that the nutritional indices albumin, transferrin and TLC have prognostic significance. Single-lumen rather than multiple-lumen catheters should be used for administration of TPN whenever possible.

Adolescent↗
PubMed1979

Intestinal pseudo-obstruction.

Intestinal pseudo-obstruction is a fairly common clinical condition. It is often asosociated with the taking of phenothiazines, tricyclic antidepressants and anti-Parkinsonian drugs, or with another disease. Treatment is conservative, unless gross colonic distension cannot be relieved or perforation is suspected. Vasopressin (Pitressin) may be a useful adjunct in management.

Aged↗
PubMed1979

Arterial reconstruction with polytetrafluoroethylene: a preliminary report.

Early results of arterial reconstruction with reinforced expanded polytetrafluoroethylene (PTFE) in the lower extremity have been obtained by reviewing 55 patients undergoing 59 operations - 38 femoropopliteal bypasses and 21 long bypasses distal to the popliteal artery. The one-year accumulated patency rates were 73% for the femoropopliteal bypass group and 50% for the long bypass group. Early results suggest that PTFE is superior to Dacron and is an acceptable substitute for autogenous saphenous vein when the latter is unavailable or of inadequate calibre.

Adult↗
PubMedDate not supplied

Prevention of prosthetic vascular graft infection by rifampicin impregnation of a protein-sealed Dacron graft in combination with parenteral cephalosporin.

Antibiotic-impregnated prosthetic vascular grafts have been shown to be highly resistant to bacterial contamination in animal models. The aim of this study was to assess if graft infection in an animal model challenged with local bacterial contamination could be reduced further by the use of rifampicin soaking of a protein-sealed Dacron graft in addition to the prophylaxis provided by perioperative intravenous cephalosporin. Of 20 Merino sheep given cefoxitin intravenously before the induction of anaesthesia, ten had a rifampicin treated Dacron graft implanted into the common carotid artery (group 1), and ten received an untreated Dacron graft (group 2). Before wound closure the grafts were inoculated with 1 ml of 10(8) colony forming units per ml of Staphylococcus aureus. After three weeks the grafts were removed and cultured. Group 1 sheep had fewer graft infections (two of 10) compared to group 2 (six of eight survivors), this difference being statistically significant (p = 0.03; Fisher exact test). It is concluded that rifampicin treatment of protein-sealed Dacron grafts combined with intravenous cefoxitin provides more protection from contaminating Staphylococcus aureus than intravenous cefoxitin alone in this animal model.

Animals↗
PubMedDate not supplied

The incidence of recurrent carotid stenosis after carotid endarterectomy and its relationship to neurological events.

We have studied the incidence of postoperative recurrent stenosis and occlusion in 286 patients, following 320 carotid endarterectomies, all of whom were commenced on low dose aspirin postoperatively. Two hundred and thirty patients (242 procedures) were examined clinically and by duplex scanning on at least two occasions at a minimum of six months apart. The crude incidence of significant recurrent carotid disease was 9.1% (22 out of 242). Seven of 22 vessels had recurrent disease detected within 24 months of operation, representing a crude incidence of 2.9% and a cumulative incidence of 4.2% at two years. The remainder developed recurrent disease after this time. Multivariate analysis of risk factors for recurrent carotid disease following carotid endarterectomy showed that a history of hypertension was significant (p = 0.001). The incidence of ipsilateral neurological events was 7.4% and was related to the presence of recurrent carotid disease (p less than 0.001).

Adult↗
PubMedDate not supplied

Laser angioplasty for superficial femoral and proximal popliteal artery occlusion.

A prospective study of percutaneous laser assisted thermal angioplasty for superficial femoral and proximal popliteal artery occlusions was performed on 93 consecutive patients with a mean length of occluded segment of 7.6 cm. Technical success was achieved in 78 patients (84%). Subsequent patency or occlusion has been confirmed by duplex ultrasound scanning or arteriography. The crude patency rate for successfully recanalised vessels was 48% during a mean follow-up period of 18 months. Subsequent femoropopliteal bypass or amputation was required in 20% of these patients. Factors predictive of reocclusion were a length of occluded segment greater than 8 cm (p = 0.05) and less than two patent vessels below the knee (p = 0.005).

Adult↗
PubMedDate not supplied

Noninvasive imaging of the superficial femoral artery using ultrasound Duplex scanning.

A total of 56 lower extremities in 28 patients were evaluated by both conventional arteriography and ultrasound duplex scanning. Overall sensitivity for duplex scanning compared to arteriography in detecting stenotic or occlusive disease was 91%, specificity was 94%, positive predictive value 85% and negative predictive value 97%. Results for Duplex scanning were better in the proximal and middle segment compared to the distal third of the superficial femoral artery. The sensitivity of segmental lower extremity pressures and pulse volume recordings for predicting proximal superficial femoral artery disease compared to arteriography was 82%; specificity was 79% and accuracy 80%, all inferior to that of Duplex scanning. Duplex scanning is a promising technique suitable for noninvasive assessment of patients presenting with suspected superficial femoral artery disease. It should readily identify candidates for percutaneous interventional techniques in which a patent segment of proximal superficial femoral artery is required for access. It will also be useful in follow-up studies of patency of the superficial femoral artery following interventional procedures such as balloon dilatation and laser angioplasty.

Aged↗