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Biomedical subjects

A J McMahon

Publications and source records attributed to A J McMahon.

At least 19 recordsLinked to original sources
PubMed2001

Acute-phase protein response, survival and tumour recurrence in patients with colorectal cancer.

INTRODUCTION: An acute-phase protein response (APPR) has been associated with reduced crude survival rates and increased recurrence following apparently curative resection in patients with colorectal cancer. This study investigated the prognostic significance of a preoperative and postoperative APPR in relation to disease-specific mortality rate. METHODS: Some 202 patients with colorectal cancer were followed for at least 5 years. C-reactive protein concentration, measured before and at 3 months after operation, was used as an index of the APPR. Univariate and multivariate analyses were performed on a number of potential prognostic factors. RESULTS: Thirty-six per cent of patients had an APPR and this was associated with a higher rate of local tumour invasion, fewer curative resections and a higher carcinoembryonic antigen (CEA) concentration. There was no difference in Dukes' stage between patients with or without an APPR. The most important prognostic factor related to both disease-specific and crude survival was Duke's stage (P < 0.0001). Subgroup analysis demonstrated that APPR had prognostic significance only in patients with advanced disease (P = 0.013). An APPR was present in a minority of patients (11 per cent) after operation and was not associated with increased likelihood of tumour recurrence. CONCLUSION: The APPR is increased in more than a third of patients presenting with colorectal cancer and is associated with more frequent local tumour invasion, fewer curative resections and a higher CEA level. An APPR at 3 months after operation does not have the prognostic significance reported by earlier studies.

Acute-Phase Reaction↗
PubMed2000

Impact of laparoscopic cholecystectomy: a population-based study.

BACKGROUND: We assessed the effect of the introduction of laparoscopic cholecystectomy on surgical outcomes in routine practice. METHODS: Hospital discharge and death-certificate data were linked for all patients undergoing cholecystectomy (n=85120) in Scottish public-sector hospitals (n=51) between January, 1981, and June, 1999. The primary endpoints were cholecystectomy rate, hospital stay, and postoperative mortality. Regression methods were used to examine the effect of laparoscopic experience and surgeon caseload on postoperative mortality and hospital stay. FINDINGS: From 1989 to 1999, the proportion of cholecystectomies done laparoscopically rose from none to 80%, and the age-standardised cholecystectomy rate increased by 20% (95% CI 15-26). Postoperative mortality did not change in the 1990s (odds ratio 0.99 [0.7-1.4], p=0.99). The mean postoperative hospital stay fell from 8.0 (SD 3.7) to 2.9 (3.2) days. There was wide variation between hospitals in the proportion of cholecystectomies done laparoscopically and in average hospital stay. For individual surgeons, increasing laparoscopic experience and annual caseload were associated with higher proportions of laparoscopic procedures and shorter hospital stays. Postoperative mortality was higher during the first ten laparoscopic cholecystectomies done by a surgeon (compared with >200 procedures, odds ratio 2.3 [1.2-4.6], p=0.015). INTERPRETATION: The laparoscopic method reduced hospital stay but had no overall effect on postoperative mortality. Studies to assess the appropriateness of the increased cholecystectomy rate are merited. The wide variation in the proportion done laparoscopically, together with evidence of better results for surgeons doing more procedures, suggests scope for further reductions in hospital stay and morbidity.

Adult↗
PubMed1995

Bile duct injury and bile leakage in laparoscopic cholecystectomy.

The introduction of laparoscopic cholecystectomy has been associated with an increased incidence of bile duct injury. This review presents the incidence of bile duct injury in reported series and examines the role of the learning curve and other contributing factors. There is good evidence to suggest that, with adequate training and experience, the incidence of biliary injury can be reduced to a level comparable to that of open cholecystectomy. Continued audit is required to ensure that the low complication rates achieved in selected centres with wide experience are reproduced by the surgical community in general.

Bile↗
PubMed1995

Symptomatic outcome 1 year after laparoscopic and minilaparotomy cholecystectomy: a randomized trial.

In a randomized controlled trial, 299 patients were sent a symptoms questionnaire 1 year after laparoscopic (n = 151) or minilaparotomy (n = 148) cholecystectomy for symptomatic cholelithiasis. The response rate to the questionnaire from contactable patients was 86 per cent. In both groups, at least 90 per cent of patients reported that their symptoms were improved, and at least 93 per cent rated the success of their operation as 'excellent', 'good', or 'fair'. However, over half the patients reported abdominal pain, a quarter reported flatulence, and a quarter dyspepsia. The only difference between treatment groups was that a higher proportion of patients who underwent minilaparotomy reported heartburn (35 per cent versus 19 per cent, P = 0.005). Patients who reported a 'poor' outcome were more likely to have suffered a postoperative complication, had lower quality of life scores, and higher anxiety and depression scores. Both laparoscopic and minilaparotomy cholecystectomy result in symptomatic benefit in at least 90 per cent of patients with symptomatic cholelithiasis.

Abdominal Pain↗
PubMed1994

Laparoscopic versus minilaparotomy cholecystectomy: a randomised trial.

Although laparoscopic cholecystectomy has rapidly become routine practice in the UK, there has been no rigorous comparison of it with open cholecystectomy. In our trial, 302 patients were randomised to laparoscopic or minilaparotomy cholecystectomy. Recovery after surgery was assessed by length of hospital stay, outpatient review at 10 days and 4 weeks, and patient questionnaires 1, 4, and 12 weeks after surgery. The mean operation time was 14 min shorter for minilaparotomy, while median post-operative hospital stay was 2 days shorter after laparoscopic cholecystectomy. The hospital costs were about 400 pounds greater for the laparoscopic procedure. Laparoscopic patients returned to work in the home sooner; at 1 week, they had better physical and social functioning, were less limited by physical problems, and had less pain and depression. At 4 weeks, only physical functioning and depression scores were better in the laparoscopic group, and by 3 months there were no differences. Laparoscopic patients were more satisfied with the appearance of their scars. The incidence of complications after both procedures was 20%. Compared to minilaparotomy cholecystectomy, laparoscopic cholecystectomy results in shorter hospital stay, less postoperative dysfunction, and quicker return to normal activities, but is more costly.

Activities of Daily Living↗
PubMed1994

Helium pneumoperitoneum for laparoscopic cholecystectomy: ventilatory and blood gas changes.

Laparoscopic cholecystectomy with carbon dioxide pneumoperitoneum may result in hypercarbia and acidosis in patients with cardiorespiratory disease. The aim of the present study was to assess helium as an alternative to carbon dioxide for creating the pneumoperitoneum. Ventilation requirements and carbon dioxide levels were assessed at the beginning and end of laparoscopic cholecystectomy using helium (n = 30) and carbon dioxide (n = 30) pneumoperitoneum. Insufflation with helium did not result in an increase in ventilation requirement although, like carbon dioxide pneumoperitoneum, it was associated with a mean rise in peak airway pressure (of 7 cmH2O; P < 0.001). There was also a 3.2-kPa increase in the alveolar-arterial oxygen gradient with helium (P = 0.006). Carbon dioxide pneumoperitoneum was associated with a significant rise in arterial carbon dioxide levels, despite increasing ventilation. Four patients with helium pneumoperitoneum had surgical emphysema for 5 days. Helium may be a suitable alternative to carbon dioxide for creating pneumoperitoneum in patients with severe cardiorespiratory disease. However, because of its low water solubility helium has a lower safety margin than carbon dioxide in the rare event of gas embolism.

Adult↗
PubMed1994

Laparoscopic and minilaparotomy cholecystectomy: a randomized trial comparing postoperative pain and pulmonary function.

BACKGROUND: Upper abdominal surgery is associated with severe postoperative pain and a concomitant reduction in pulmonary function and oxygen saturation. Laparoscopic cholecystectomy is said to result in less postoperative pain compared with open cholecystectomy. METHODS: In a pragmatic, randomized trial, postoperative pain, opiate analgesic consumption, oxygen saturation, and pulmonary function (forced vital capacity, forced expiratory volume in 1 second, and peak expiratory flow rate) were assessed after laparoscopic (n = 67) and minilaparotomy (n = 65) cholecystectomy. RESULTS: Compared with minilaparotomy cholecystectomy, laparoscopic cholecystectomy was associated with lower linear analogue pain scores (median 40 vs 59, p < 0.001), lower patient-controlled morphine consumption (median 22 vs 40 mg, p < 0.001), a smaller reduction in postoperative pulmonary function (mean peak expiratory flow rate 64% of preoperative value vs 49%, p < 0.001), and better oxygen saturation (mean 92.9% vs 91.2%, p = 0.008). CONCLUSIONS: This study confirms that the postoperative pain and pulmonary changes associated with upper abdominal surgery are significantly reduced by the laparoscopic technique. These findings suggest that laparoscopic cholecystectomy may result in a reduced risk of postoperative pulmonary complications.

Adult↗
PubMed1993

Ventilatory and blood gas changes during laparoscopic and open cholecystectomy.

As part of a randomized trial, ventilatory and arterial blood gas changes were assessed during open (n = 30) and laparoscopic (n = 30) cholecystectomy. Measurements were made during anaesthesia before the start of surgery and at the time of removal of the gallbladder. Despite an increase in minute ventilation from a mean(s.d.) of 5.7(1.4) to 6.1(1.2) litres, mean(s.d.) arterial carbon dioxide tension (PaCO2) rose from 5.3(0.9) to 6.0(0.9) kPa during laparoscopic cholecystectomy. End-tidal carbon dioxide tension (PE'CO2) had poor precision in predicting PaCO2 (95 per cent interval of agreement -0.61 to 1.93 kPa). Mean(s.d.) peak airway pressure increased from 17(4) to 23(4) cmH2O. The mean PaCO2--PE'CO2 value did not change significantly, although there was significant within-patient variation. Arterial oxygen levels did not change significantly. By comparison, no clinically significant changes in ventilation or blood gas values occurred during open cholecystectomy. In conclusion, laparoscopic cholecystectomy requires a substantial but variable increase in minute ventilation to compensate for carbon dioxide absorption from the peritoneum.

Adult↗
PubMed1993

Comparison of metabolic responses to laparoscopic and minilaparotomy cholecystectomy.

This randomized study compared the metabolic responses to laparoscopic cholecystectomy (n = 10) and minilaparotomy cholecystectomy with a 5-7-cm incision (n = 10). Venous blood samples were taken before operation and at 3, 6, 9, 12, 18, 24, 48, 72 and 168 h after incision and analysed for levels of C-reactive protein, interleukin 6, cortisol, albumin, transferrin, iron, fibrinogen, fibrin degradation products and polymorphonuclear elastase, and for neutrophil and lymphocyte counts. Urine samples (24 h) were analysed for urea, creatinine, 3-methylhistidine and catecholamines. The magnitude of the metabolic changes from baseline levels was quantified by calculating areas under each individual curve. A significant metabolic response with a similar time course and magnitude of changes occurred after laparoscopic and minilaparotomy cholecystectomy but with wide variation in magnitude between individuals.

Adult↗
PubMed1993

Combined predeposit and salvage autotransfusion in elective aortic aneurysm repair.

In this study assessing the safety and value of the routine use of autotransfusion in elective aortic aneurysm surgery, the first 16 patients (control group) received homologous transfusion only, while the subsequent 38 patients (autotransfusion group) received a combination of predeposit and salvage autotransfusion (Solcotrans device). Between 1 and 3 units of blood were venesected preoperatively, and a median of 0.80 (0.20-2.75) litres of unwashed shed blood was salvaged and re-infused (48% of the measured blood loss). A median of 4 units of banked blood was required in the control group compared with 2 units in the autotransfused group, an average saving of 2 units per patient (P < 0.001). Banked blood was avoided completely in 37% of patients in the autotransfusion group. There were no haematological or biochemical complications. Predeposit and salvage autotransfusion is simple and safe, and reduces banked blood requirement in aortic aneurysm surgery.

Aortic Aneurysm↗
PubMed1992

Needle core biopsy of the breast with a spring-loaded device.

Over a 2-year period, 151 outpatients with a palpable breast lump requiring needle core biopsy were randomized to a Tru-Cut 14-G (T14), Bioptycut 14-G (B14) or Bioptycut 18-G (B18) needle. Use of a Biopty gun resulted in less pain than a Tru-Cut needle. An inadequate sample was obtained after two needle passes in 11 of 49 (T14), none of 51 (B14) and two of 51 (B18) patients (chi 2 = 14.6, 2 d.f., P = 0.0007). Tissue samples were assessed by a single pathologist for tissue volume and overall diagnostic value; the B14 group scored better than the B18 and T14 for both of these parameters (P < 0.003). The sensitivities were 68 (T14), 88 (B14) and 96 (B18) per cent (overall chi 2 = 7.3, 2 d.f., P = 0.026). The Biopty gun with a 14-G needle results in a higher sampling success rate, greater diagnostic sensitivity and a better specimen quality than the Tru-Cut, and is much easier to use.

Adult↗