Robert C. Mason

Identification of futility in intensive care

Rising costs of intensive care and the ability to prolong the life of critically ill patients creates a need to recognise early those patients who will die despite treatment. We used changes in a modified APACHE II score (organ failure score) to make daily predictions of individual outcome in 3600 patients. 137 patients were predicted to die and of these, 131 (95.6%) died within 90 days of discharge from hospital (sensitivity 23.4%, specificity 99.8%); a false-positive diagnosis rate of 4.4%. 2 of the 6 survivors have subsequently died but 4 are alive with good quality of life. Patients predicted to die stayed 1492 days in intensive care and incurred 16.7% of total intensive care expenditure and 46.4% of the cost of all patients that died. Median survival after a prediction to die was 2 days, accounting for 62% of intensive care patient days in this patient group, giving an effective intensive care cost per survivor of UK 129,651 pounds. If used prospectively, this algorithm has the potential to indicate the futility of continued intensive care but at the cost of 1 in 20 patients who would survive if intensive care were continued.

Intraoperative assessment of colonic perfusion using scanning laser Doppler flowmetry during colonic resection.

BACKGROUND Ischemia occurring on mobilization and mesenteric division is thought to be a major factor in the etiology of anastomotic dehiscence after colorectal resection. This study assessed the ability of the new technique of scanning laser Doppler flowmetry to measure changes in human colonic perfusion during mobilization at and adjacent to the anastomotic site. STUDY DESIGN Colonic perfusion was measured in 10 patients undergoing large-bowel resection by making laser Doppler scans of the proximal bowel before mobilization, after mobilization and mesenteric division, and after resection of the specimen. Mean perfusion was calculated within 1-cm2 regions of interest, each of which contained 1,750 individual measurements of perfusion. These regions represented the anastomosis site and adjacent areas 1 cm and 2 cm proximal and distal to this. The results were expressed as mean perfusion units (PUs). RESULTS After mobilization, there were significant decreases in perfusion in all the subjects between each time point and in all areas of the colon scanned. Median perfusion at the anastomosis site was 491 PUs before mobilization, and this fell to 212 PUs after mobilization, representing a decrease of 57%; the median within-person decrease was also 57% (p < 0.01). There was a gradient of reduced perfusion between the area 2 cm proximal to the mesenteric division (median within-person fall 25%; p < 0.05) and the area 2 cm distal to the mesenteric division (median within-person fall 84%; p < 0.01). After resection of the specimen, perfusion increased slightly at the anastomosis site to a median of 240 PUs (median within-person fall 41%; p < 0.01), but 2 cm proximal to this, median perfusion remained depressed at 330 PUs. CONCLUSIONS This new technique can be used intraoperatively and appears to overcome the limitations of single-point laser Doppler flowmetry. In this small preliminary study, it measured large decreases in colonic perfusion during mobilization, and it may have widespread clinical applications.

Plastic-covered metallic endoprostheses in the management of oesophageal perforation in patients with oesophageal carcinoma

OBJECTIVE To evaluate the role of plastic-covered self-expanding metallic endoprostheses in patients with oesophageal perforation occurring during endoscopically guided dilatation prior to laser treatment for malignant obstruction. SUBJECTS AND METHODS Six patients with oesophageal perforation following laser treatment for malignant obstruction were treated. Four patients received the polyurethane-covered Wallstent endoprosthesis (Schneider SA, Bulach, Switzerland) and two patients the barbed polyethylene-covered Gianturco stent (William Cook, Europe). RESULTS All patients had successful stent placement under intravenous sedation and fluoroscopic guidance with immediate relief of dysphagia and sealing of the perforation. Following the procedure all patients could eat either a normal diet or soft food and five patients were discharged within 3-4 days. None of the serious sequelae usually associated with oesophageal perforation were observed. Two patients required second overlapping stents to be inserted within 1 week because of minor migration of the initial endoprostheses. In one patient two stents were necessary because the carcinoma extended over 17 cm. Five patients died after stent insertion (mean survival time = 49 days, range 16-80; median survival time = 37 days, range 16-80) due to a general deterioration in their condition, although all could swallow normally until death. The remaining patient was well and tolerating a light diet at 1 month. CONCLUSION This technique is quick, safe and cost-effective and is now our preferred method of managing malignant oesophageal obstruction associated with perforation.

Intraoperative scanning laser doppler flowmetry in the assessment of gastric tube perfusion during esophageal resection

BACKGROUND Ischemia from tissue hypoperfusion in the gastric tube after esophagectomy is believed to contribute significantly to postoperative complications associated with anastomotic failure. This study assessed the ability of the new technique of laser Doppler flowmetry to measure differential levels of blood flow in human gastric tubes during esophagectomy. STUDY DESIGN Gastric perfusion was measured in 16 patients undergoing esophagectomy by making laser Doppler scans of the stomach before mobilization and after formation of the gastric tube. Mean perfusion was calculated within the whole anterior surface of the stomach or tube and within 1 cm2 regions of interest, each of which contained 1,750 individual measurements of perfusion. These regions represented the cephalic end of the gastric tube, 10 adjacent 1 cm2 regions distally along the tube, and the proposed anastomosis site. Results were expressed as mean perfusion units, and tissue blood flow from each scan in each region was compared. RESULTS There were significant decreases in gastric perfusion measured with the scanning laser Doppler in all patients after formation of the gastric tube. Mean perfusion of the stomach fell 41% (p<0.0005) after mobilization. In all patients there was a gradient of perfusion from the proximal end of the tube where flow was poor, to more distal areas where it was higher. At the proximal end of the tube perfusion fell by a mean of 72%, 5 cm distally the mean fall was 44%, and 10 cm from the proximal end of the tube the mean fall was 28%. At the anastomosis site mean perfusion fell 55%. CONCLUSIONS This new technique can be used intraoperatively and appears to overcome the limitations of single point laser Doppler flowmetry. It has measured large differences in perfusion at different sites within the gastric tubes and could therefore have widespread clinical applications.

GASTRIC INTRAMUCOSAL PH PREDICTS OUTCOME AFTER SURGERY FOR RUPTURED ABDOMINAL AORTIC ANEURYSM

OBJECTIVE The mortality associated with repair of ruptured abdominal aortic aneurysms (RAAA) remains obstinately high and many deaths result from multiple organ failure which is likely to be related to splanchnic ischaemia. The aim of this study is to investigate the importance of splanchnic ischaemia in determining outcome from RAAA by comparing gastric intramucosal pH with other methods of assessing the adequacy of splanchnic oxygenation. DESIGN AND SETTING Prospective cohort of patients following surgery for RAAA admitted to the Intensive Care Unit of Guys Hospital, London. OUTCOME MEASURES Gastric intramucosal pH (pHim) and global haemodynamic, oxygen transport and metabolic variables were measured on admission, at 12 h and at 24 h after admission. Results were compared between survivors and non-survivors and Receiver Operating Characteristic (ROC) curves were constructed to assess the ability of each measurement to predict outcome. RESULTS The median 24 h APACHE II was 18 and the ICU mortality 45.5%. Gastric pHim was significantly higher in survivors than non-survivors at 24 h (7.42 vs. 7.24, p < 0.01). In survivors who had a low intramucosal pH (pHim) on admission there was a significant improvement over the first 24 h (7.26 to 7.40, p < 0.05), whereas in patients who subsequently died, and had a normal pHim on admission, there was a significant fall in pHim (7.35 to 7.16, p < 0.05). ROC curves showed that gastric pHim was the most sensitive measurement for predicting outcome in these patients. CONCLUSIONS Gastric intramucosal pH is the most reliable indicator of adequacy of tissue oxygenation in patients with RAAA, suggesting that splanchnic ischaemia may have played an important role in determining survival.

Effect of gastric resection, Roux-en-Y diversion and vagotomy on gastric emptying in the rat

Solid and liquid gastric emptying studies were conducted in 61 male Wistar rats. In 20 animals a two-thirds Pólya-type gastric resection was performed and 21 had a similar resection with a 10-cm Roux-en-Y diversion. In nine of the Roux diversions truncal vagotomy was also carried out. Twenty animals acted as controls: ten unoperated and ten that received laparotomy only. Body-weight and gastric emptying were measured weekly for 4 weeks and monthly for 4 months after surgery. Animals subjected to gastrectomy revealed a weight loss of approximately 16 per cent after operation. Weight gain was slower after Roux reconstruction than after Pólya-type anastomosis and slowest in animals with vagotomy and Roux drainage (P < 0.05). Gastric emptying was unchanged in unoperated controls. Animals in which a laparotomy was performed had delayed solid and liquid emptying for the first 4 weeks after operation (P < 0.05). Following Pólya-type gastrectomy, liquid emptying was delayed for 4 months. Solid emptying was unchanged, with no evidence of the delay present in animals with a laparotomy. Animals subjected to Roux-en-Y diversion showed a greater delay in liquid emptying than those with a Pólya resection; solid emptying was also delayed (P < 0.05). Severe gastric retention of liquids and solids occurred in the early postoperative phase when vagotomy was added to the Roux diversion (P < 0.01). Emptying of solids adopted a relatively normal linear pattern after this initial retention. Emptying of liquids, however, remained abnormal, appearing to adopt a biphasic pattern.

Self-expanding metallic stents in the management of pyloric dysfunction after gastric pull-up operations.

Abstract. The purpose of this paper is to report the use and benefits of self-expanding metallic stents employed in pyloric dysfunction. Four patients treated with oesophagectomy and gastric pull-up for oesophageal carcinoma failed to respond to balloon dilatation for pyloric dysfunction. Three of the patients were thought to have residual tumour at sites remote from the pylorus prior to stenting, but the fourth, who had undergone surgery 8 years previously, was thought to be cured. All were treated with self-expanding metallic stents. All four patients responded well with resolution of their symptoms. Over a mean follow-up of 6 months there has been no recurrence of symptoms. Stent insertion represents a potentially valuable method of treatment in patients with post-surgical pyloric dysfunction in whom simple balloon dilatation has failed.

Treatment of a malignant esophageal perforation with a prototype conical wallstent

A 60-year-old man with a malignant esophageal perforation could not be treated by conventional covered metallic stents because the upper esophagus was dilated. The perforation was eventually closed by deployment of a prototype, conical covered Wallstent.

Sequential endoscopy and biopsy of intact rat stomach

This paper describes the technique of sequential endoscopy and biopsy of the intact rat stomach. It is recommended that this procedure be performed on fasted animals with access to water only, when a mortality of only 4% can be achieved.This paper describes the technique of sequential endoscopy and biopsy of the intact rat stomach. It is recommended that this procedure be performed on fasted animals with access to water only, when a mortality of only 4% can be achieved.