D. S. Byrne

B‐type natriuretic peptide predicts cardiac morbidity and mortality after major surgery

The objective of this study was to determine whether measurement of B‐type natriuretic peptide (BNP) concentration before operation could be used to predict perioperative cardiac morbidity.

Value of sentinel node status as a prognostic factor in melanoma: prospective observational study

Abstract Objective To establish the prognostic value of knowledge of sentinel node status in melanoma. Design Single centre prospective observational study, with sentinel nodes identified by lymphoscintigraphy, γ probe, and intraoperative blue dye and examined by both conventional histopathology and immunopathology. Setting Specialist surgical service in west of Scotland. Participants 482 patients with melanoma who consented to sentinel node biopsy in 1996-2003. Main outcome measure Time to recurrence of or death from melanoma. Results Of 472 patients who consented to sentinel node biopsy and in whom at least one sentinel node was identified, 367 (78%) had no tumour in the sentinel node. At mean follow-up of 42 months, 299 (82%) of this group were alive and free from disease, 24 were alive with melanoma recurrence, and 31 had died of melanoma. Of 105 patients with a positive sentinel node biopsy, 44 (42%) were alive and disease free, 12 were alive with recurrence, and 46 had died of melanoma. The survival difference between patients who were negative and those who were positive for tumour in the sentinel node was highly significant at all thickness levels over 1.0 mm (P < 0.001). Multivariate analysis showed that sentinel node status was independent of tumour thickness and ulceration. 71/105 (68%) patients with a positive sentinel node had a negative completion lymphadenectomy, and 44/71 (62%) were alive and disease free at follow-up; 34 patients with a positive sentinel node had further nodes involved, and only 4 (12%) were disease free (P < 0.001). 16 patients (13 sentinel node biopsy positive; 3 negative) died of other causes. Conclusion Sentinel node status is a highly significant predictor of prognosis in melanoma and should be considered in adjuvant studies. However, it should not be regarded as a standard of care until mature data from ongoing randomised trials are available.

Ten-year experience of carbon dioxide laser ablation as treatment for cutaneous recurrence of malignant melanoma.

Cutaneous recurrence of malignant melanoma is distressing for the patient, can be difficult to palliate and is resistant to treatment by conventional methods. Experience with carbon dioxide laser ablation was reviewed to determine the initial efficacy, time to recurrence, number of treatments required and length of palliation achieved.

Cardiopulmonary responses to treadmill and cycle ergometry exercise in patients with peripheral vascular disease

BACKGROUND Peripheral arterial disease (PAD) presenting as intermittent claudication (IC) is routinely assessed as the distance or time walked to the onset of pain, which often occurs before significant cardiopulmonary stress and is subject to confounding factors such as increased body mass and altered gait. Thus, where exercise-induced cardiovascular stress is desirable, such as in cardiac stress testing or clinical trials, an alternative modality of exercise is required. Cycling will circumvent several of the associated problems of treadmill walking and may provide an alternative preferable method of exercise, although there is limited information on the physiologic response of patients with PAD to cycling. This study compared the peak cardiorespiratory responses and the repeatability of cycling and treadmill exercise in patients with PAD. METHODS Ten men (mean age, 54 +/- 10 years) with stable IC completed two incremental exercise tests to the limit of tolerance on a treadmill and a cycle ergometer after familiarization with the outcome measures of exercise duration, work performed, respiratory gas exchange variables using continuous breath-by-breath measurement, heart rate, and ratings of perceived pain. RESULTS Both methods of exercise assessment revealed high reproducibility in terms of absolute claudication time (treadmill, r = 0.95; cycle, r = 0.91), time to volitional fatigue (treadmill, r = 0.96; cycle, r = 0.91), and cardiopulmonary exercise responses such as the lactate threshold (treadmill, r = 0.95; cycle, r = 0.94), peak heart rate (treadmill, r = 0.94; cycle, r = 0.96), and peak oxygen uptake (treadmill, r = 0.98; cycle, r = 0.87). Cycling induced significantly higher cardiopulmonary responses (peak heart rate, peak carbon dioxide output, peak minute ventilation, and respiratory exchange ratio) than treadmill exercise. There was no difference in time to volitional fatigue or in absolute claudication time between exercise modalities. CONCLUSION These results demonstrate that exercise testing using cycling offers an alternative method of cardiopulmonary testing for patients with IC that is equally reliable and reproducible to treadmill walking. Cycling may be preferable to treadmill exercise because it induces greater cardiopulmonary and metabolic responses and is better tolerated by patients.

Measurement of process as quality control in the management of acute surgical emergencies

Quality of care measured by adverse events cannot address errors of process that have no adverse outcomes. The aim of this study was to determine whether process could be used to assess quality of care and whether process analysis could be used to assess interventions designed to improve quality.

A single centre's 10 year experience with isolated limb perfusion in the treatment of recurrent malignant melanoma of the limb

The aim of this study was to assess whether isolated limb perfusion can be performed safely and whether it offers improved disease-free survival for patients with limb malignant melanoma. Between August 1983 and July 1993, 103 patients (78 female, 25 male) with recurrent limb melanoma were treated by isolated limb perfusion (ILP) in Glasgow, U.K. The mean age of the patients was 62 years; 95 had leg recurrence, 8 had arm recurrence. The mean time from original diagnosis to ILP was 48 months (range 1-290). 102 iliac, 5 femoral, 7 popliteal and 8 axillary perfusions were performed. All patients had stage II (local recurrence within 3 cm of primary site) or stage III (regional metastases; tissues excluding nodes, nodes or combination) disease according to the MD Anderson Cancer Centre Staging System. At a mean follow-up of 30.7 months, 68 patients had died of recurrent disease (mean time to death 22.5 months). The 2 and 5 year survival of the group was 50 and 26%, respectively and disease-free survival was 23 and 12%, respectively. At first perfusion, 76% of patients showed complete response and 23% showed partial response. With repeat perfusion, 47% showed complete response and 53% had partial response. In conclusion, ILP is safe and has an acceptable morbidity. It achieves highly satisfactory local disease control but long-term survival is the exception.

Common iliac artery access during endovascular thoracic aortic repair facilitated by a transabdominal wall tunnel.

Purpose: To describe a technique for common iliac artery (CIA) access during endovascular aortic aneurysm repair when unfavorable angulation between the CIA and the delivery sheath precludes direct arterial access. Technique: After retroperitoneal exposure of the CIA, a puncture site is chosen inferolateral to the surgical incision, and an 18-G trocar/cannula is advanced in alignment with the CIA through the anterior abdominal wall or skin of the upper thigh into the retroperitoneal space. Serial dilatation is performed over a guidewire placed through the cannula to create the subcutaneous tract. The trocar/cannula is replaced over the wire, and the CIA is punctured under direct vision. The guidewire is then advanced into the proximal aorta. A CIA arteriotomy is performed and the delivery system introduced over the guidewire through the tunnel into the iliac artery. Conclusions: Retroperitoneal exposure of the CIA with tunneled transabdominal wall delivery of the stent-graft avoids both external iliac artery injury and creation of a temporary access conduit in patients with iliac tortuosity and/or occlusive disease.

Pharmacokinetics and tissue penetration of vancomycin continuous infusion as prophylaxis for vascular surgery

OBJECTIVES To determine the tissue penetration of vancomycin into perivascular fat and arterial wall during a continuous infusion of vancomycin, given as prophylaxis for vascular surgery. PATIENTS AND METHODS Patients undergoing arterial reconstruction requiring antibiotic prophylaxis were included. Patients received a loading infusion of vancomycin the evening prior to surgery followed by a continuous 24 h infusion, calculated according to renal function. Three peri-operative serum samples and intra-operative perivascular fat and arterial wall samples were collected for vancomycin assay. RESULTS Twenty-eight patients were included. Three serum samples were obtained from all patients, fat samples were available from 27 (96.4%) patients and vessel wall samples were available from 23 (82.1%) patients. Serum vancomycin concentrations were maintained within a relatively narrow range, while fat and arterial wall concentrations were highly variable. CONCLUSIONS This study has shown that prophylactic administration of vancomycin with a loading infusion followed by a continuous infusion before and during vascular surgery achieves serum and vascular tissue concentrations that are above the MICs for most common organisms implicated in post-operative graft infection. However, penetration into perivascular fat tissues is poor.

Are routine microbiological investigations indicated in the management of non-perianal cutaneous abscesses?

BACKGROUND It is common practice to take a specimen of pus for microscopy and bacterial culture during drainage of abscesses. The aim of this study was to determine if routine culture and sensitivity had any therapeutic value in the care of patients with non-perianal cutaneous abscesses. PATIENTS AND METHODS A retrospective analysis ofall patients undergoing drainage ofa cutaneous abscess during a two year period (June 2003 - June 2005) was performed. Patients were identified from the hospital database and theatre records, and those with perianal, pilonidal or surgical wound sepsis were excluded. Notes were reviewed for clinical details, culture results, subsequent admissions and attendance at follow-up. RESULTS Of the 239 patients treated during this period, 74 patients had 77 operations to drain abscesses that matched the inclusion criteria. Specimens were sent from 52 (67.5%) procedures. Only 65.4% had an organism identified, of which methicillin-sensitive Staphylococcus aureus (MSSA) was the most commonly isolated organism (36.5%). Forty-one point six per cent of patients received antibiotics as part of their treatment. The results of the bacterial culture and antibiotic sensitivities were not known prior to discharge of any patient. CONCLUSION This study shows that bacteriology swabs are frequently taken during incision and drainage of non-perianal cutaneous abscesses and had little impact on the subsequent treatment, though these results may not be applicable to immune-compromised patients.

A comparison of dosinietric methods in isolated limb perfusion with melphalan for malignant melanoma of the lower extremity

The three dosimetric schedules currently used in isolated limb perfusion with melphalan for malignant melanoma of the lower limb were compared in a series of 51 patients. The doses prescribed by each of the three methods (based on total body weight (TBW), limb tissue volume (LTV) and total blood volume in the perfusion circuit (TBV)) were calculated for all patients and were then compared using Wilcoxons signed-rank test. This revealed that the method based on TBV consistently prescribed much lower doses of drug than either of the other two methods. Pharmacokinetic profiles of melphalan obtained by HPLC analysis of blood samples during the procedure also showed that the method did not reliably predict the concentration of melphalan achieved in the perfused limb. The dosimetric schedule based on LTV prescribed slightly higher doses than that based on TBW. However, the technique is more difficult to practise due to the problems of measuring the limb volume by immersion. We conclude that the dosimetric schedule based on TBW is the most appropriate by virtue of its simplicity, the high doses of melphalan which it prescribes, and the well-controlled toxicity which it produces.