In vivo measurement of liver perfusion in the normal and partially hepatectomized rat using Tc-99m sulfur colloid.

A nonsacrificial technique for measurement of liver perfusion in rats using Tc-99m sulfur colloid and gamma camera with computer system is described. The results of measurement in normal rats and at various stages after partial hepatectomy are presented and are compared with results obtained by workers using other techniques. The method reported here is simpler to perform than those previously reported and has the additional advantage that frequent sequential determinations of liver perfusion can be made.

In vivo assessment of hepatic-arterial and portal-venous components of liver perfusion: concise communication.

An in vivo technique for assessment of the relative contributions of hepatic artery and portal vein to liver perfusion has been developed in the rat. Dynamic scintigrams have been obtained following i.v. bolus injection of Tc-99m sulfur colloid. Temporal separation of the arterial and venous phases has been verified by hepatic-arterial ligation and portacaval diversion. The former procedure abolishes the early arterial phase of normal uptake. Portacaval diversion similarly eliminates the delayed venous phase. Assessment of the individual components of liver perfusion is of promise in the investigation of hepatic dysfunction.

Alterations in liver blood flow and reticuloendothelial function in progressive cirrhosis in the rat.

Cirrhosis of the liver was induced in rats by twice weekly inhalation of carbon tetrachloride in conjunction with sodium phenobarbitone administration. At sequential time intervals during induction, liver blood flow and extraction efficiency of colloid were assessed in order to elucidate changes in these parameters which occur with cirrhosis. Liver samples were also taken for histologic examination and graded for extent of disease. Initially there was a fall in extraction efficiency (and thus reticuloendothelial function), associated with early histologic change. Subsequently extraction efficiency recovered, as regeneration was observed on histologic specimens. From 4 wk and onward, blood flow gradually fell, as did extraction efficiency. These changes were associated with increasing severity of disease as demonstrated by histologic sections.

Scintigraphic estimation of arterial and portal blood supplies to the liver.

A technique is described for the measurement of the relative magnitudes of the hepatic-artery and portal-vein components of liver perfusion, using a gamma camera and on-line computer system. This ratio is obtained from analysis of the time variation in liver activity on the first pass following bolus intravenous injection of a Tc-99m-labeled radiocolloid. The arterial and portal components are separated by their times of arrival at the liver. These arrival times are evaluated from activity time variations for spleen, left ventricle, and left kidney. Physiological validation of the technique was provided in a digestion study in which normal volunteers showed a significant increase in the portal-vein component 1 hr after a meal relative to the fasting situation. These results are compared with those from studies by other workers. The uncertainties and limitations of the technique are discussed and potential clinical uses suggested.

Uptake of a colloid in rat liver following intravenous intrasplenic and intramesenteric injection.

Intramesenteric and intrasplenic injections of 99mTc-sulfur colloid in the rat resulted in significant differences between the mean uptakes in only some of the liver lobes. More important were the wider interlobular variations seen in the intrasplenic and intramesenteric routes of injection compared with the intravenous route. It is suggested that these differences result from laminar blood flow in the portal vein. In the light of our findings, previous evidence must be considered inconclusive. Laminar flow appears to vary between individual animals and may also vary from time to time in the same animal. Caution is therefore advised when other than systemic routes of injection are used.

In vivo assessment of liver size in the rat.

In vivo assessment of liver mass in the rat was achieved using several parameters obtained by scintigraphy, including one computed using a Nuclear Data 50:50 analysis system. All correlated well with the directly measured liver weight. The simplest parameter, the area of the anterior view measured from the Polaroid scintigraph, was therefore the one preferred. The results so obtained were compared with those derived from the relationship between liver and body weights. It is suggested that this accurate in vivo measurement of liver mass is of value in the study of the pathophysiology of this organ.

Effects of N-methyl-thiotetrazole cephalosporin on haemostasis in patients with reduced serum vitamin K1 concentrations.

Two patients with low random serum vitamin K1 concentrations but with normal prothrombin times and normal biological assays of the vitamin K dependent coagulation proteins were treated with an N-methyl-thiotetrazole cephalosporin (cefotetan) postoperatively. Four to six days later both patients developed a prolonged prothrombin time and a noticeable and specific lowering of the clotting activities of factors II, VII, IX and X, though the serum vitamin K1 concentrations remained unchanged. Crossed immunoelectrophoresis of prothrombin showed the appearance of a second peak corresponding to descarboxyprothrombin (PIVKA II). These abnormalities corrected after vitamin K administration. These data are consistent with the hypothesis that cephalosporins with an N-methyl-thiotetrazole side chain inhibit the hepatic utilisation of vitamin K but that this only causes hypoprothrombinaemia when liver reserves of vitamin K are low.

Studies of hepatic tolerance of polyvinylpyrrolidone in the rat.

Intraperitoneal polyvinylpyrrolidone in amounts much larger than used in povidone-iodine for peritonitis or for adhesion prophylaxis was administered to rats. No adverse effects on hepatic reticulo-endothelial function could be detected using dynamic hepatic scintigraphy and fewer histochemical changes occurred than expected.

A randomized prospective study to compare cefotetan with cefuroxime plus metronidazole as prophylaxis in elective colorectal surgery.

This study compares the efficacy of cefotetan with the combination of cefuroxime plus metronidazole as antibiotic prophylaxis in elective colorectal surgery when given over the first 24 h postoperatively. There was no significant difference in wound infection rates between the two groups (14.7% for cefotetan and 13.9% for cefuroxime plus metronidazole), or the rates of other infective complications. Adverse reactions occurred with equal frequency in both treatment groups and no serious side effects occurred. Cefotetan is a safe and effective antibiotic for use as prophylaxis in elective colorectal surgery. Its advantages are that it is a single agent with a spectrum covering both aerobic Gram-negative rods and anaerobic organisms and, because of its long half-life, needs only to be given at 12-hourly intervals.

A randomized prospective study to compare ceftizoxime with cephradine as single dose prophylaxis in elective cholecystectomy.

This study compares the efficacy of ceftizoxime with that of cephradine as single agent prophylaxis in elective cholecystectomy. The incidence of purulent wound infection was low in both groups (ceftizoxime 1/99; cephradine 2/92). No adverse reactions to the trial antibiotics occurred in either group. Ceftizoxime is a safe, effective, convenient and well-tolerated antibiotic for use as single agent prophylaxis in elective cholecystectomy. However, because it has no demonstrable advantage over cephradine and is three times as expensive, its routine use is not justified.

Enhanced retention of urea-nitrogen in patients on total parenteral nutrition for intestinal failure.

Urea, the main end product of human nitrogen metabolism, is either excreted in the urine or salvaged for further metabolic interaction, through the activity of the colonic microflora. In patients on TPN (total parenteral nutrition) the bowel is 'defunctioned' insofar as the microflora are deprived of exogenous substrate, and it might be expected that urea salvaging is reduced to low levels. The recovery of labelled urea-nitrogen was measured in 7 patients on TPN and compared with 4 normals. Following a single intravenous dose of 15N15N-urea, urine was collected for 48h and analysed for 15N. In normals the median retention of 15N was 17% (range 13-17) of the dose compared with 38% (24-52) in 5 TPN patients not on antibiotics (p < 0.05). TPN patients on antibiotics retained 11 and 15%. Despite the absence of exogenous substrate, the 'defunctioned' bowel of patients on TPN appears more active in hydrolysing urea than in normals, and the hydrolysis is sensitive to the effect of antibiotics.

Detection of dangerous malnutrition.

The assessment of malnutrition by simple methods was studied in 120 patients undergoing elective major abdominal surgery to determine which index was of the most value in predicting postoperative complications. Weight for height and weight loss were of little significant value; serum albumin less than 35 g/l was more significant (p less than 0.05) but predicted only a quarter of those patients who developed serious complications. Measurements of muscle stores by anthropometry (arm and forearm muscle circumference) predicted nearly half the patients (p less than 0.01). By far the most useful index was hand-grip dynamometry, which predicted 90% of those who developed complications (p less than 0.001). The incidence of serious complications was 6 times greater in those patients with a low grip strength. Hand-grip dynamometry appears to be a useful screening test of patients at risk, and a valuable additional test for nutritional assessment.

Non-invasive assessment of absolute values of hepatic haemodynamics using radiocolloid scintigraphy.

A non-invasive technique for the assessment of hepatic haemodynamics using radiocolloid imaging with a computer, in which absolute values of hepatic, mesenteric and splenic arterial effective blood flows were assessed, is described. The technique was carried out on ten volunteers, before and after a standard meal. After eating, total effective liver blood flow rose by 28% and the mesenteric arterial effective flow by 69%. Hepatic and splenic arterial effective flow were reduced.

Regional indices of relative hepatic arterial perfusion from dynamic liver scintigraphy: the variability of indices and the use of parametric imaging.

Regional indices of relative arterial hepatic perfusion have been studied in 21 control subjects following dynamic radiocolloid scintigraphy of the liver (DLS). Three different indices have been calculated: the hepatic perfusion index (HPI); the hepatic arterial ratio (HAR) and the mesenteric fraction (MF). Three regions were defined in the upper, mid and lower right hepatic lobes and the three indices were calculated for each region. There was reasonable agreement between regional values of the same index with inter-regional correlation coefficients above 0.7 and standard errors in straight line fits of less than 0.093. There were significant regional differences for (1-MF) and HPI indices, but not for HAR. The index (1-MF) was calculated for each pixel and presented as a parametric image in 16 control subjects. The parametric images indicated the raised regional arterial indices due to overlying lung, right kidney and aorta. Parametric images may be of value to show the hepatic area free of significant overlying tissue and therefore available for analysis by DLS. However, the results suggest that the observed variability of single pixel indices limit the potential of parametric imaging for the localization of small focal lesions.

Noninvasive assessment of portosystemic shunting in extrahepatic portal hypertension in rats.

A simple reproducible animal model of extrahepatic portal hypertension (EHPHT) has been developed in weanling Wistar rats using a two-stage ligation of the portal vein. This model consistently produces substantial collaterals, both portosystemic (hepatofugal) and portoportal (hepatopetal). Using dynamic hepatic scintigraphy (DHS) with 99mTechnetium sulphurcolloid, hepatopetal collateral flow was measured as the mesenteric fraction (MF) of total hepatic blood flow and compared with measurement of hepatofugal collateral flow (portosystemic shunting) following intraportal injection of radiolabeled microspheres. Strong and significant correlation between the two assessments was found with reduction in MF denoting increased portosystemic shunting (PSS). The technique of DHS has been used successfully in adults to assess compromised portal venous flow and is a simple noninvasive test to aid diagnosis, assessment, and follow-up of children with EHPHT.

Cefotetan in the treatment of serious intra-abdominal sepsis: a controlled clinical trial.

Cefotetan has been compared with two regimens of combination antibiotic therapy in the treatment of peritonitis and serious intra-abdominal sepsis. One hundred predominantly elderly patients (median age 66 years) were entered into a prospective randomized surgical trial. Sixty-two per cent had peritonitis. There were seven non-septic deaths. Side-effects were similar in each group and generally of a minor, self limiting nature. Haematological and biochemical factors were closely monitored, and though there were increases in the prothrombin time, there was no statistical difference between cefotetan and comparators. Cefotetan is as effective as combination therapy in the treatment of surgical patients with serious intra-abdominal sepsis.

Review of the perceptions of general surgical staff within the Wessex region of the status of quality assurance and surgical audit.

The opinion of surgical staff about the present state and effectiveness of surgical audit within a single regional health authority has been obtained by questionnaire. Seventy-five per cent of registrars/senior registrars and 72 per cent of consultants completed and returned the proforma. The majority of registrars (86 per cent) believe that it is vital or very important to collect clinical outcome information that is relevant, accurate and complete. However, more than half (56 per cent) felt that these objectives were not being met. All consultants also agreed with the statement that meaningful surgical audit and quality assurance must be based on confidential critical peer review of relevant, accurate, ongoing and complete information. None, however, believed that this objective was being met completely, while only 41 per cent felt that they were doing even 'fairly well', with the principle reason for failure being lack of time. These results support the view that most surgeons are keen to achieve meaningful audit, but at present this objective is not being satisfactorily met.

Postoperative complications: how much do they cost?

Complications following major abdominal surgery incur considerable expense. The aims of this study were to analyse prospectively the costs of complications following major abdominal surgery and to compare such costs with those of elective distal large bowel resection. Six patients undergoing elective resection for large bowel cancer were studied at the Royal South Hants Hospital between January and March 1983. The mean cost of resection and primary anastomosis, without postoperative complications, was pounds 1,364 (n = 4). Indirect costs accounted for 38%, nursing 25%, medical staff 13%, investigations 8% and consumables 16%. The operation itself accounted for 12% of the total. Complications following major abdominal surgery were studied in a further ten patients. The costs of complications not prolonging hospital stay were: wound infection pounds 64-146; chest infection pounds 21-27; urinary infection pounds 3-6. Complications prolonging hospital stay resulted in considerably greater cost: pelvic abscess pounds 1245; myocardial infarction pounds 476; subphrenic abscess pounds 857; colostomy retraction pounds 764; wound dehiscence pounds 599; incisional hernia pounds 1723, and major chest infection pounds 258. Owing to high fixed costs, the main factor in determining cost for bowel resection and complications was length of hospital stay.

Clinical evaluation of percutaneous insertion and long-term usage of a new cuffed polyurethane catheter for central venous access.

A new, long-term venous access catheter was evaluated in clinical practice and the insertion time, complication rate and prospective follow-up recorded. Fifty novel polyurethane catheters (Cuff-Cath) were inserted in 48 patients, for cytotoxic chemotherapy in 36, long-term total parenteral nutrition in five and miscellaneous indications in seven. All catheters were inserted by a percutaneous technique under local anaesthesia. The mean insertion time was 18 min. There were three insertion complications; failure to cannulate, pneumothorax and malposition. Seven catheters required removal (sepsis in five, subclavian vein thrombosis in two) and one catheter fell out. Total catheter days to date has been 6607 (mean 132, range 18-831 days). Eleven catheters are still in use a mean of 154 days (range 38-490 days) after insertion. Furthermore, a new technique has been described which prevents inadvertent displacement. This new catheter combines the mechanical advantages of polyurethane, together with those of a Dacron cuff. Early results suggest that this catheter may be a useful alternative to silicone catheters of the Hickman/Broviac type for long-term central venous access.

The practical management of Fournier's gangrene.

Effective early treatment of this serious condition is necessary to prevent death. Urgent exploration by the most experienced surgeon available should include wide excision of all necrotic or dubious tissue, and adequate drainage of deep fascial planes. Deep and apparently healthy tissues must be exposed and the surgeon must be prepared to proceed to laparotomy, and even diverting colostomy and/or suprapubic cystotomy when necessary. Cross matched blood must be available, and we have found hydrogen peroxide irrigation useful. Pus, tissues, and blood samples for bacteriological culture and sensitivity should always be sent, but broad spectrum antibiotics should be started without delay to prevent systemic complications. In addition to the urgent initial surgery, repeated daily examination of all wounds is necessary, usually under general anaesthesia to allow full inspection, further débridement, irrigation and change of dressings, until the infective process is halted. This is a serious condition with a high mortality which we believe may be reduced by early diagnosis and appropriate aggressive surgery.