Laparoscopic assisted colectomy: experience from a rural centre.

BACKGROUND: This study presents an audit of the first 50 elective laparoscopic assisted colorectal resections carried out at the Launceston General Hospital, Tasmania, particularly in comparison with the 33 elective open resections carried out in the same 18-month period. METHODS: This was a retrospective review and analysis of prospectively recorded data on an intention-to-treat basis using non-parametric methods. RESULTS: With respect to case selection, patients in the laparoscopic group were younger (median = 63 years (range 19-98 years) vs 69 years (33-93 years), P = 0.0392) and more patients had benign pathology (22/50, 44% vs 4/33, 12%, P = 0.002). There was no significant difference in sex or American Society of Anesthesiologists status (P = 0.499 and 0.517, respectively). There were more left-sided than right-sided resections (28/50, 56% vs 14/33, 42%, P = 0.118), along with more total colectomies in the laparoscopic group (7 vs 2). Operation times in the laparoscopic group were longer (197.5 min (87-452 min) vs 144 min (70-260 min), P = 0.0002) and no significant reduction was recorded over the study period (P = 0.50). There were five conversions from laparoscopic to open procedure (a 10% incidence). Compared with the open colectomy group, patients who underwent laparoscopic resections required less parenteral analgesia (2 days (1-5 days) vs 3 days (0-6 days), P < 0.0001). They had earlier first flatus (3 days (1-7 days) vs 4 days (1-6 days), P = 0.0069) and bowel movement (3 days (1-7 days) vs 4 days (2-9 days), P = 0.0021), tolerated solid diet earlier (3 days (1-9 days) vs 4 days (1-30 days), P = 0.0001) and had shorter hospital stay (5 days (3-12 days) vs 7 days (4-37 days), P = 0.0009). Less major perioperative complications were recorded for the laparoscopic group (2/50 vs 4/33, P = 0.162), but very little difference was found with respect to minor complications (17/50 vs 10/33, P = 0.725). For carcinoma resections, there were no positive resection margins. In the laparoscopic group, tumour size was smaller (3.25 cm (1-7 cm) vs 5 cm (2-15 cm), P = 0.0014) and less lymph nodes were harvested (6 (2-16) vs 8 (3-23), P = 0.101). CONCLUSION: Laparoscopic colectomy allowed early postoperative recovery and shorter hospital stay. This was at the expense of a longer operation. It can be taken up by relatively laparoscopically naive surgeons without extra major morbidity/mortality associated with the learning curve. It is technically feasible and safe in small centres.

Prediction of failure of native arteriovenous fistulas using 'on-line' fistula flow measurements.

BACKGROUND: Measurement of blood flow within native arteriovenous fistula during haemodialysis is recommended to detect incipient fistula failure. In the present study the value of such flow measurements was assessed in a group of patients on maintenance haemodialysis, with access via native arteriovenous fistulas. METHODS: Flow was measured using the 'on-line' thermodilution technique, on three separate occasions, and correlated with subsequent fistula failure within 6 months. RESULTS: Of the 53 patients studied, there were six failures (three thromboses and three inadequate dialysis filtration rates). Flow rates in patients who progressed to fistula failure were significantly less than flow rates in patients whose fistulas did not fail (U = 13.0, P < 0.0003). Failure was no more common in one type of fistula than another (type fistula: F = 0.29, P = 0.88; flow predicting failure: F = 7.22, P = 0.010). Receiver operating characteristic (ROC) curve analyses confirmed flow measurement to be a useful predictor of fistula failure (area under ROC curve 0.91). The optimal threshold of 576 mL/min flow gave a sensitivity of 89% and a specificity of 81%. Measurement of access resistance was less useful in predicting failure (area under ROC curve 0.87). Measurement of fall in flow from the previous measurement was of no use (area under ROC curve 0.535). CONCLUSION: On-line thermodilution measurement of flow within established native arteriovenous fistula is useful in surveillance and early prediction of fistula failure. Fistula flow <576 mL/min may indicate incipient native fistula failure, and should prompt further investigation.

Confidence limits of arteriovenous fistula flow rate measured by the "on-line" thermodilution technique.

BACKGROUND: A method is presented for estimating the confidence limits (CLs), or accuracy, of the arteriovenous fistula flow rate measured at haemodialysis by the "on-line" thermodilution technique. METHODS: This was by derivation of an expression to estimate what variance a set of repeated measures of flow would yield, using values pertaining to a single measure of flow. (Laws of variance were applied to the formula used to calculate flow, to account for its variables' values and measurement errors.) This enabled CLs of a single measure to be estimated. RESULTS: The variance estimated from a single measure was compared with that actually observed upon immediately taking a second measurement; differences in 189 pairs were not significantly different from zero (P=0.56). Applying the results demonstrated that measured flow values of 430-570 ml/min typically had associated 95% CLs that included 500 ml/min; therefore, true flow could not be said to be either side of 500 ml/min. The same was the case for 500-700 ml/min with regard to 600 ml/min. CLs widened considerably with the magnitude of flow rate, limiting the accurate measurement of higher flows and the detection of falls in flow. CONCLUSION: A method to estimate CLs of flow rate measured by the thermodilution technique is presented and validated. Application demonstrates an accurate measurement of low flow, but limitations at higher flow and in detecting falls in flow. Appreciating the magnitude of such is critical to informed clinical decision making when using flow rate in an access surveillance programme.