Detection of circulating tumor necrosis factor after endotoxin administration

Cytokines, products of stimulated macrophages, are thought to mediate many host responses to bacterial infection, but increased circulating cytokine concentrations have not been detected consistently in infected patients. We measured plasma concentrations of circulating tumor necrosis factor alpha (cachectin), interleukin-1 beta, and gamma interferon, together with physiologic and hormonal responses, in 13 healthy men after intravenous administration of Escherichia coli endotoxin (4 ng per kilogram of body weight) and during a control period of saline administration. Eight additional subjects received ibuprofen before receiving endotoxin or saline. Plasma levels of tumor necrosis factor were generally less than 35 pg per milliliter throughout the control period, but increased 90 to 180 minutes after endotoxin administration to mean peak concentrations of 240 +/- 70 pg per milliliter, as compared with 35 +/- 5 pg per milliliter after saline administration. Host responses were temporally associated with the increase in circulating tumor necrosis factor at 90 minutes, and the extent of symptoms, changes in white-cell count, and production of ACTH were temporally related to the peak concentration of tumor necrosis factor. Ibuprofen pretreatment did not prevent the rise in circulating tumor necrosis factor (mean peak plasma level, 170 +/- 70 pg per milliliter) but greatly attenuated the symptoms and other responses after endotoxin administration. Concentrations of circulating interleukin-1 beta and gamma interferon did not change after endotoxin administration. We conclude that the response to endotoxin is associated with a brief pulse of circulating tumor necrosis factor and that the resultant responses are effected through the cyclooxygenase pathway.

Enhanced recovery after surgery: a consensus review of clinical care for patients undergoing colonic resection

BACKGROUND & AIMS

Clinical care of patients undergoing colonic surgery differs between hospitals and countries. In addition, there is considerable variation in rates of recovery and length of hospital stay following major abdominal surgery. There is a need to develop a consensus on key elements of perioperative care for inclusion in enhanced recovery programmes so that these can be widely adopted and refined further in future clinical trials.

METHODS

Medline database was searched for all clinical studies/trials relating to enhanced recovery after colorectal resection. Relevant papers from the reference lists of these articles and from the authors' personal collections were also reviewed. A combination of evidence-based and consensus methodology was used to develop the resulting enhanced recovery after surgery (ERAS) clinical care protocol.

RESULTS AND CONCLUSIONS

Within traditional perioperative practice there is considerable evidence supporting a range of manoeuvres which, in isolation, may improve individual aspects of recovery after colonic surgery. The present manuscript reviews these issues in detail. There is also growing evidence that an integrated multimodal approach to perioperative care can result in an overall enhancement of recovery. However, effects on major morbidity and mortality remain to be determined. A protocol is presented which is in current use by the ERAS Group and may provide a standard of care against which either current or future novel elements of an enhanced recovery approach can be tested for their effect on outcome.

Consensus guidelines for enhanced recovery after gastrectomy: Enhanced Recovery After Surgery (ERAS®) Society recommendations

BACKGROUND

Application of evidence-based perioperative care protocols reduces complication rates, accelerates recovery and shortens hospital stay. Presently, there are no comprehensive guidelines for perioperative care for gastrectomy.

METHODS

An international working group within the Enhanced Recovery After Surgery (ERAS®) Society assembled an evidence-based comprehensive framework for optimal perioperative care for patients undergoing gastrectomy. Data were retrieved from standard databases and personal archives. Evidence and recommendations were classified according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system and were discussed until consensus was reached within the group. The quality of evidence was rated 'high', 'moderate', 'low' or 'very low'. Recommendations were graded as 'strong' or 'weak'.

RESULTS

The available evidence has been summarized and recommendations are given for 25 items, eight of which contain procedure-specific evidence. The quality of evidence varies substantially and further research is needed for many issues to improve the strength of evidence and grade of recommendations.

CONCLUSION

The present evidence-based framework provides comprehensive advice on optimal perioperative care for the patient undergoing gastrectomy and facilitates multi-institutional prospective cohort registries and adequately powered randomized trials for further research.

A protocol is not enough to implement an enhanced recovery programme for colorectal resection

BACKGROUND

Single-centre studies have suggested that enhanced recovery can be achieved with multimodal perioperative care protocols. This international observational study evaluated the implementation of an enhanced recovery programme in five European centres and examined the determinants affecting recovery and length of hospital stay.

METHODS

Four hundred and twenty-five consecutive patients undergoing elective open colorectal resection above the peritoneal reflection between January 2001 and January 2004 were enrolled in a protocol that defined multiple perioperative care elements. One centre had been developing multimodal perioperative care for 10 years, whereas the other four had previously undertaken traditional care.

RESULTS

The case mix was similar between centres. Protocol compliance before and during the surgical procedure was high, but it was low in the immediate postoperative phase. Patients fulfilled predetermined recovery criteria a median of 3 days after operation but were actually discharged a median of 5 days after surgery. Delay in discharge and the development of major complications prolonged length of stay. Previous experience with fast-track surgery was associated with a shorter hospital stay.

CONCLUSION

Functional recovery in 3 days after colorectal resection could be achieved in daily practice. A protocol is not enough to enable discharge of patients on the day of functional recovery; more experience and better organization of care may be required.

A single dose of endotoxin increases intestinal permeability in healthy humans

To investigate the effects of endotoxin on gut barrier function, we performed paired studies of intestinal permeability in healthy humans (N = 12) receiving intravenous Escherichia coli endotoxin (4 ng/kg) or 0.9% saline solution. Two nonmetabolizable sugars, lactulose and mannitol, which are standard permeability markers, were administered orally, 30 minutes before and 120 minutes after the test injection. The 12-hour urinary excretion of these substances after endotoxin/saline solution administration was used to quantitate intestinal permeability. After endotoxin administration systemic absorption and excretion of lactulose increased almost two-fold (mean +/- SEM, 263 +/- 36 mumol per 12 hours vs 145 +/- 19 mumol per 12 hours during saline studies). Similar but less marked alterations in mannitol absorption and excretion occurred after endotoxin injection (5.7 +/- 0.3 mmol per 12 hours vs 4.9 +/- 0.3 mmol per 12 hours). When individual 12-hour lactulose excretion after endotoxin administration was related to the magnitude of systemic responses, a significant relationship occurred between lactulose excretion and elaboration of norepinephrine and between lactulose excretion and minimum white blood cell count. These data suggest that a brief exposure to circulating endotoxin increases the permeability of the normal gut. These observations are consistent with the hypothesis that during critical illness, prolonged or repeated exposure to systemic endotoxins or associated cytokines may significantly compromise the integrity of the gastrointestinal mucosal barrier.

Initial experience with a multimodal enhanced recovery programme in patients undergoing liver resection

Background

Accelerated recovery from surgery has been achieved when patients are managed within a multimodal Enhanced Recovery After Surgery (ERAS) protocol. This study evaluated the benefit of an ERAS programme for patients undergoing liver resection.

Methods

The ERAS protocol of epidural analgesia, early oral intake and early mobilization was studied prospectively in a consecutive series of 61 patients. Outcomes were compared with those in a consecutive series of 100 patients who underwent liver resection before the start of the study. Endpoints were postoperative length of hospital stay, postoperative resumption of oral intake, readmissions, morbidity and mortality.

Results

Fifty-six patients (92 per cent) in the ERAS group tolerated fluids within 4 h of surgery and a normal diet on day 1 after surgery. Median hospital stay, including readmissions, was 6·0 days compared with 8·0 days in the control group (P < 0·001). There were no significant differences in rates of readmission (13 and 10·0 per cent respectively), morbidity (41 and 31·0 per cent) and mortality (0 and 2·0 per cent) between ERAS and control groups.

Conclusion

The ERAS fast-track protocol is safe and effective for patients undergoing liver resection. It allows early oral intake, promotes faster postoperative recovery and reduces hospital stay.

Inhibition of cyclo-oxygenase attenuates the metabolic response to endotoxin in humans

Acute infection initiates fever, acute-phase changes, and catabolic responses in the host, resulting in weight loss, hypermetabolism, and accelerated proteolysis. To test the hypothesis that cyclo-oxygenase inhibition might attenuate these responses, we administered Escherichia coli endotoxin intravenously to seven normal volunteers and to seven additional subjects pretreated with a cyclo-oxygenase inhibitor (ibuprofen). Control studies were also performed following administration of saline and ibuprofen alone. Vital signs, metabolic rate, and concentrations of pituitary and stress hormones, as well as those of other substrates, were serially measured. Endotoxin administration produced a response similar to an acute illness, with flulike symptoms, fever, tachycardia, increased metabolic rate, and stimulation of stress hormone release. These changes were markedly attenuated by cyclo-oxygenase inhibition. The leukocytosis, hypoferremia, and elevation of the C-reactive protein level induced by endotoxin were unaffected by cyclo-oxygenase inhibition. These data indicate that activation of the cyclooxygenase pathway is necessary to produce many of the metabolic changes observed during critical illness.

Growth hormone after abdominal surgery attenuated forearm glutamine, alanine, 3-methylhistidine, and total amino acid efflux in patients receiving total parenteral nutrition

OBJECTIVE

The study clarified the effects of growth hormone treatment on forearm amino acid efflux in patients with full nutritional support after gastrointestinal surgery.

SUMMARY BACKGROUND DATA

Growth hormone attenuates net nitrogen loss after surgical trauma. An increase in net protein synthesis has been described, whereas the results regarding protein breakdown have been conflicting.

METHODS

Elective patients undergoing abdominal surgery were double blindly randomized to treatment with recombinant human growth hormone (GH, n = 9) 24 IU or placebo (PL, n = 10) the first 5 postoperative days. All received parenteral nutrition (nitrogen = 5.7 +/- .1 g/m2, energy = 1018 +/- 12 kcal/m2 (125 +/- .7% of BMR) and epidural analgesia. Amino acid plasma levels and forearm fluxes were measured.

RESULTS

The second postoperative day, growth hormone abolished forearm efflux of total amino acid nitrogen (GH: 170 +/- 117, PL: -785 +/- 192 nmol/100 mL/min, p = .0007) due to reduced losses of both essential and nonessential amino acids. Glutamine release was abolished (13 +/- 15 vs. -137 +/- 43 nmol/100 mL/min, p = .007) and alanine release attenuated (-61 +/- 17 vs. -211 +/- 51 nmol/100 mL/min, p = .01). 3-Methyl-histidine release was attenuated (-.20 +/- .11 vs. -.62 +/- .09 nmol/100 mL/min, p = .04). Growth hormone also induced decreased venous plasma amino acid levels.

CONCLUSIONS

When given after gastrointestinal surgery in patients treated with total parenteral nutrition, growth hormone treatment abolished glutamine, 3-methylhistidine, and total amino acid nitrogen loss from forearm tissue. Alanine loss from forearm tissue was attenuated.

Vasoactive intestinal polypeptide and somatostatin in leucocytes

Vasoactive intestinal polypeptide (VIP) was measured in extracts from polymorphonuclear (PMN) and mononuclear (MN) leucocytes from 14 healthy persons and 12 pigs. In addition, extracts from PMN and MN cells from eight pigs were studied for possible contents of somatostatin. Immunoreactive VIP was present in the PMN and MN leucocytes from man and pigs with a significantly higher level in the MN cells. Similarly, immunoreactive somatostatin was found in both cell lines from pigs with a significant higher amount in the MN leucocytes. Furthermore, extracts from pure populations of human PMN and MN leucocytes were separately applied on a Sephadex G-50 Fine column, and VIP, somatostatin, secretin, GIP and motilin were measured in the eluted fractions. Only VIP and somatostatin were found to be present in detectable amounts. Immunoreactive VIP eluted corresponding to the elution volume for pure porcine VIP in extracts from both PMN and MN cells, while immunoreactive somatostatin eluted corresponding to the elution volume for the synthetic tetradecapeptide somatostatin in extracts from MN cells only. Possible physiological implications of these findings are briefly discussed.

The effects of tumor necrosis factor and their selective inhibition by ibuprofen

High doses of tumor necrosis factor (TNF) cause hypotension, metabolic acidosis and, death. At Brigham and Women's Hospital, the effects of a sublethal, 6-hour infusion of TNF (0.57 X 10(5) Units/kg body weight) in twelve anesthetized dogs were studied. The dose caused falls in mean arterial pressure from 153 mmHg to 96 mmHg, pulmonary artery pressure (-4.5 mmHg), central venous pressure (-2.5 mmHg) and pulmonary capillary wedge pressures (-5.25 mmHg). Associated with these responses were a fourfold increase in urine volume (22.4 ml/kg/6 hours as compared to 5.2 ml/kg/6 hours in controls), significant pyrexia (from 38.1 C to 39.5 C, rectal), tachycardia (from 125 to 175 beats/minute), and hypermetabolism. In addition, leukopenia and increased circulating stress hormone concentrations were observed. Blood glucose concentrations fell from 4.68 mM/1 to 3.97 mM/1 (84-71 mg/dl) within 3 hours of TNF infusion, whereas lactate and pyruvate concentrations increased. These alterations occurred in the absence of severe hypotension or acidosis and were similar to changes observed after endotoxin administration or gram-negative septicemia. Pretreatment of the animals with the cyclooxygenase inhibitor ibuprofen abolished most of the hemodynamic changes and attenuated other responses. These findings support the hypothesis that TNF is an important mediator of septic responses and that some of the effects of TNF are mediated via cyclooxygenase pathways.

Patterns in current anaesthesiological peri-operative practice for colonic resections: a survey in five northern-European countries

BACKGROUND

For colorectal surgery, evidence suggests that optimal management includes: no pre-operative fasting, a thoracic epidural analgesia continued for 2 days post-operatively, and avoidance of fluid overload. In addition, no long-acting benzodiazepines on the day of surgery and use of short-acting anaesthetic medication may be beneficial. We examined whether these strategies have been adopted in five northern-European countries.

METHODS

In 2003, a questionnaire concerning peri-operative anaesthetic routines in elective, open colonic cancer resection was sent to the chief anaesthesiologist in 258 digestive surgical centres in Scotland, the Netherlands, Denmark, Sweden and Norway.

RESULTS

The response rate was 74% (n = 191). Although periods of pre-operative fasting up to 48 h were reported, most (> 85%) responders in all countries declared to adhere to guidelines for pre-operative fasting and oral clear liquids were permitted until 2-3 h before anaesthesia. Solid food was permitted up to 6-8 h prior to anaesthesia. In all countries more than 85% of the responders indicated that epidural anaesthesia was routinely used. Except for Denmark, long-acting benzodiazepines were still widely used. Short-acting anaesthetics were used in all countries except Scotland where isoflurane is the anaesthetic of choice. With the exception of Denmark, intravenous fluids were used unrestrictedly.

CONCLUSION

In northern Europe, most anaesthesiologists adhere to evidence-based optimal management strategies on pre-operative fasting, thoracic epidurals and short-acting anaesthetics. However, premedication with longer-acting agents is still common. Avoidance of fluid overload has not yet found its way into daily practice. This may leave patients undergoing elective colonic surgery at risk of oversedation and excessive fluid administration with potential adverse effects on surgical outcome.

Risk factors, complications and survival after upper abdominal surgery: a prospective cohort study

Background

Preoperative weight loss and abnormal serum-albumin have traditionally been associated with reduced survival. More recently, a correlation between postoperative complications and reduced long-term survival has been reported and the significance of the relative proportion of skeletal muscle, visceral and subcutaneous adipose tissue has been examined with conflicting results. We investigated how preoperative body composition and major non-fatal complications related to overall survival and compared this to established predictors in a large cohort undergoing upper abdominal surgery.

Methods

From 2001 to 2006, 447 patients were included in a Norwegian multicenter randomized controlled trial in major upper abdominal surgery. Patients were now, six years later, analyzed as a single prospective cohort and overall survival was retrieved from the National Population Registry. Body composition indices were calculated from CT images taken within three months preoperatively.

Results

Preoperative serum-albumin <35 g/l (HR = 1.52, p = 0 .014) and weight loss >5 % (HR = 1.38, p = 0.023) were independently associated with reduced survival. There was no association between any of the preoperative body composition indices and reduced survival.

Major postoperative complications were independently associated with reduced survival but only as long as patients who died within 90 days were included in the analysis.

Conclusions

Our study has confirmed the robust significance of the traditional indicators, preoperative serum-albumin and weight loss. The body composition indices did not prove beneficial as global indicators of poor prognosis in upper abdominal surgery. We found no association between non-fatal postoperative complications and long-term survival.

Adjuvant chemotherapy (5-fluorouracil and levamisole) in Dukes' B and C colorectal carcinoma. A cost-effectiveness analysis

BACKGROUND

Adjuvant chemotherapy (5-fluorouracil, levamisole) is now standard practice in the treatment of Dukes' B and C coloretal carcinoma (CRC), and this has increased the financial burden on health care systems world-wide.

PATIENTS AND METHODS

Between 1993 and 1996, 95 patients in northern Norway were included in a national randomised CRC study, and assigned to surgery plus adjuvant chemotherapy or surgery alone. In April 1996, 94 of the patients were evaluable and 82 were still alive. The total treatment costs (hospital stay, surgery, chemotherapy, administrative and travelling costs) were calculated. A questionnaire was mailed to all survivors for assessment of the quality of their lives (QoL) (EuroQol questionnaire, a simple QoL-scale, global QoL-measure of the EORTC QLQ-C30), and 62 of them (76%) responded.

RESULTS

Adjuvant chemotherapy in Dukes' B and C CRC raised the total treatment costs by 3,369 pounds. The median QoL was 0.83 (0-1 scale) in both arms. Employing a 5% discount rate and an improved survival of adjuvant therapy ranging from 5% to 15%, we calculated the cost of one gained quality-adjusted life-year (QALY) to be between 4,800 pounds and 16,800 pounds.

CONCLUSION

Using a cut-off point level of 20,000 pounds per QALY, adjuvant chemotherapy in CRC appears to be cost-effective only when the improvement in 5-year survival is > or = 5%. Adjuvant chemotherapy does not affect short-term QoL.

Effects of in vivo endotoxin infusions on in vitro cellular immune responses in humans

Studies of the immune response of patients following major injury have identified significant abnormalities, some of which may be due to the effects of endotoxin. To evaluate the effect of endotoxin on the immune system without conflicting variables, we studied 18 normal, healthy male volunteers each on two occasions. In one study, Escherichia coli endotoxin was administered intravenously at a dose of 4 ng/kg. In the other, saline was given. Blood for immune function studies was obtained at either 0, 4, or 24 hr (seven volunteers), 0, 1, and 4 hr (five volunteers), or 0, 4, and 6 hr (six volunteers) postinfusion. Peripheral blood mononuclear cells (PBMC) were isolated and adjusted to the same concentration. Measurements following endotoxin infusion were compared with those of the same volunteers following saline infusion and with those from normal ambulatory laboratory volunteers. Interleukin 1 (IL-1) production by adherent cells was significantly reduced at 1 hr post endotoxin infusion. Significant decreases in number of mononuclear cells, response to phytohemagglutinin (PHA), and production of IL-2 and IL-1 were observed by 4 hr after endotoxin infusion. No significant changes in percentages of monocytes, lymphocytes, or CD3, CD4, or CD8 lymphocytes were observed at any time. By 24 hr postinfusion all values had returned to normal or, in some cases, supranormal levels. Response to PHA by PBMC from volunteers 4 hr following endotoxin was completely restored by in vitro addition of recombinant human IL-2 but was only marginally improved by IL-1. In vitro addition of indomethacin to PBMC cultures responding to PHA reduced the suppression observed after in vivo endotoxin but also was not as effective as IL-2. In a fourth study, seven volunteers were treated as above either with two doses (800 mg each) of the cyclooxygenase inhibitor ibuprofen before endotoxin infusion or with ibuprofen alone. Ibuprofen pretreatment completely restored the PBMC response to PHA to normal and caused a significant decrease in the endotoxin-induced suppression of IL-2 production. However, the decrease in circulating PBMC number and adherent cell secretion of IL-1 was not affected by inhibition of the cyclooxygenase pathway. These results suggest that endotoxin has immunomodulatory effects on both adherent mononuclear-cell and T-lymphocyte function and that more than one mechanism is involved.

Impact of radiotherapy on local recurrence of rectal cancer in Norway

Background

The purpose of this study was to analyse the impact of radiotherapy on local recurrence of rectal cancer in Norway after the national implementation of total mesorectal excision (TME).

Methods

This was a prospective national cohort study of 4113 patients undergoing major resection of rectal carcinoma between November 1993 and December 2001.

Results

The proportion of patients who had radiotherapy before or after operation increased from 4·6 per cent in 1994 to 23·0 per cent in 2001. The cumulative 5-year local recurrence rate decreased from 16·2 to 10·7 per cent. Multivariable analysis showed that preoperative radiotherapy significantly reduced local recurrence (hazard ratio 0·59 (95 per cent confidence interval 0·39 to 0·87)). The use of preoperative radiotherapy in patients from a local hospital offering radiotherapy was 50 per cent higher than that for patients from a hospital without such services (P = 0·003); cumulative 5-year local recurrence rates for these patients were 10·6 and 15·8 per cent respectively (P &lt; 0·001).

Conclusion

Following national implementation of TME for rectal cancer, increased use of preoperative radiotherapy appeared to reduce recurrence rates further.

Tumor necrosis factor and interleukin 1 appearance in experimental gram-negative septic shock. The effects of plasma exchange with albumin and plasma infusion

To study the effect of plasma removal vs plasma administration on the appearance of tumor necrosis factor (TNF) and interleukin 1 in septic shock, 24 anesthetized piglets were inoculated with live Escherichia coli. Plasma exchange with albumin was performed in one group. Fresh-frozen plasma was administered to a second group. A third group served as nontreated controls. Following plasma exchange, a reduction in both TNF and interleukin 1 levels occurred, whereas plasma infusion was followed by a decrease in TNF levels only. No significant differences were observed between the two treated groups with respect to survival or cardiovascular performance, with both being significantly enhanced compared with the controls. High levels of TNF and interleukin 1 correlated with depressed cardiovascular performance in the early phase of the shock. Our results confirm the important role of TNF and interleukin 1 as early mediators of septic shock. However, the benefit of reducing cytokine activity in later stages of septicemia seems to be dubious.

Renal elimination of protein S-100beta in pigs with acute encephalopathy

BACKGROUND

Protein S-100beta is an established biochemical marker for cerebral injury in serum. For the further interpretation and possible use of S-100beta serum measurements in acute hepatic encephalopathy, renal elimination of S-100beta was measured in pigs with elevated S-100beta levels due to hepatic encephalopathy.

METHODS

Eighteen female Norwegian Landrace pigs were randomly allocated to either hepatic devascularization (n=13) or sham operation (n=5). Repeated samples from the common carotid artery, right renal vein, and urine were simultaneously drawn for S-100beta analysis, using the Sangtec100 Liamat immunoassay.

RESULTS

In hepatic devascularized pigs, arterial serum levels of S-100beta increased from 0.96+/-0.04 microg/L (mean +/- SEM) at t = 0h to 1.74+/-0.11 microg/L (mean +/- SEM) at t = 5 h. Urinary excretion increased simultaneously from 8.48+/-3.66 ng/h (mean +/- SEM) to 20.4+/-9.54 ng/h (mean +/- SEM), while renal arterial-venous fluxes for both kidneys increased from 1022+/-404 ng/h (mean +/- SEM) to 2444+/-590 ng/h (mean +/- SEM).

CONCLUSIONS

Increased arterial S-100beta levels in pigs with acute hepatic encephalopathy are not a result of decreased renal elimination. The large difference between the renal arterial venous S-100beta concentrations and the urinary excretion of S-100beta indicate that renal metabolism is the major route of elimination.

N-acetylcysteine increases cerebral perfusion pressure in pigs with fulminant hepatic failure

OBJECTIVE

Intravenous administration of N-acetylcysteine beyond 15 hrs reduces mortality rates in patients suffering from paracetamol-induced fulminant hepatic failure, although the mechanism of the therapeutic benefit remains unclear. We hypothesized increased survival to be caused by improved hemodynamic performance. The main objective for the study was to explore the effect of N-acetylcysteine on hemodynamics, oxygen transport, and regional blood flow in pigs with fulminant hepatic failure.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Surgical research laboratory in a university hospital.

SUBJECTS

Female Norwegian Landrace pigs.

INTERVENTIONS

Fulminant hepatic failure was induced by a total liver devascularization procedure. Five hours later, the pigs were allocated to N-acetylcysteine treatment (150 mg.kg-1 in 100 mL of 0.9% saline over 15 mins, followed by 50 mg.kg-1 in 500 mL of 0.9% saline over a period of 4 hrs) or placebo.

MEASUREMENTS AND MAIN RESULTS

Mean arterial pressure stabilized in the N-acetylcysteine group and increased slightly during the last 2 hrs (pGT =.009). Thus, mean arterial pressure was significantly higher compared with placebo after 3 hrs (p =.01). Cerebral perfusion pressure was significantly higher during the last 2 hrs in the N-acetylcysteine group (pGT =.033). Common carotid artery flow also increased and was maintained at a higher level compared with placebo (pG =.027). Systemic vascular resistance index initially decreased but then gradually increased (pGT <.001). Cardiac index increased after 15 mins of N-acetylcysteine infusion, causing a significant interaction (pGT =.038), but did not differ after 3 hrs. No significant differences in hindleg and mesentery hemodynamics were found. A short-lived increase in oxygen delivery caused by a temporary increase in cardiac index was observed but without any corresponding increase in oxygen consumption.

CONCLUSIONS

Intravenous N-acetylcysteine infusion increases cerebral perfusion pressure in pigs with fulminant hepatic failure. Earlier reported effects on oxygen transport and uptake could not be confirmed.

An experimental large animal model for the assessment of bioartificial liver support systems in fulminant hepatic failure

BACKGROUND

Pre-clinical assessment of bioartificial liver support systems requires a highly reproducible large animal model. The main objective of the present study was to develop a valid large animal model for assessing novel bioartificial liver support systems in fulminant hepatic failure.

METHODS

A complete liver devascularization procedure was performed in 10 female pigs weighing 25-38 kg. Five matched pigs were sham-operated and served as controls.

RESULTS

Pigs with fulminant hepatic failure developed a hyperdynamic circulation, with increased cardiac index (P(GT) < .0001), decreased systemic vascular resistance index (P(GT) < .0001) and mean arterial pressure (P(GT) = .001). Furthermore, intracranial hypertension developed (P(GT) < .0001). with increased common carotid artery flow (P(GT) < .0001) and decreased common carotid resistance (P(G) = .003). Femoral artery flow increased (P = .036). while hindleg resistance (P < .001) and renal artery resistance decreased (P = .019). Oxygen consumption (P(GT) = .050) and oxygen extraction ratio (P(GT) = .001) increased compared to controls. Arterial ammonia, venous aspartate aminotransferase and bilirubin levels increased (P(GT) < .0001, respectively). Abnormal haemostasis developed with significant loss of platelets (P(GT) = .010), decreasing fibrinogen levels (P(G) = .001) and increasing international normalized ratio (P(GT) = .012) and activated clotting time (PGT < .001). Urine became hypo-osmotic (P < .001. P(G) = .011), with decreased sodium levels (P = .08) and increased potassium levels (P(G) = .025).

CONCLUSIONS

This study characterizes a reproducible large animal model for fulminant hepatic failure that seems suitable for the assessment of bioartificial liver support systems.

Liver transplantation in patients with splenorenal shunts: intraoperative flow measurements to indicate shunt occlusion

Two patients with previous distal splenorenal shunts (DSRSs) performed 6 years earlier underwent liver transplantation (LT). A preoperative selective mesenteric artery angiogram showed collateral veins draining mesenteric venous flow into the shunt. Intraoperative flow measurements were performed to assess the steal of portal venous flow by the shunt and determine the need for shunt occlusion. Portal vein, hepatic artery, and shunt flows were measured by ultrasound transit-time flow probes in the native liver and after graft implantation with and without temporary shunt occlusion. Hemodynamic studies showed that long-standing DSRSs are high-flow shunts that steal portal flow. After graft implantation, DSRS flows remained high. Occlusion of the shunts produced an increase in portal vein flow at an amount similar to those of splenorenal shunt. Thus, the flow measurements showed persistent steal by the shunts after graft implantation and, therefore, the DSRSs were occluded but splenectomy was not performed. We conclude that the decision to occlude a DSRS should be based on the demonstration of steal of portal flow by the shunt and reversibility once the shunt is occluded. Splenectomy is not required when the DSRS is occluded.

Liver regeneration in surgical animal models - a historical perspective and clinical implications

METHODS/AIMS: Despite improved preoperative evaluation, surgical techniques and perioperative intensive care, some patients still experience postoperative liver failure in part due to insufficient regeneration. The aim of this review is to give the reader a historical synopsis of the major trends in animal research on liver regeneration from the early experiments in 1877 up to modern investigation. A major focus is placed on the translational value of experimental surgery.

METHODS

A systematic review of the English literature published in Medline was undertaken with the search words 'pig, porcine, dog, canine, liver regeneration, experimental'.

RESULTS

The evolution of the various models tentatively explaining the process of liver regeneration is described.

CONCLUSIONS

We conclude by emphasizing the importance of large-animal surgical research on liver regeneration as it offers a more integrated, systemic biological understanding of this complex process. Furthermore, in our opinion, a closer collaboration between the hepatologist, liver surgeon/transplant surgeon and the laboratory scientist may advance clinically relevant research in liver regeneration.

Introducing an asymmetric cleft lift technique as a uniform procedure for pilonidal sinus surgery

BACKGROUND AND AIMS

Asymmetric techniques for surgery in pilonidal sinus disease (PSD) have been reported to provide better results than simple excision and closure in the midline. The aim of this retrospective study was to evaluate the results after introducing the Bascom asymmetric cleft lift procedure in our hospital on a day care basis.

MATERIAL AND METHODS

From a total of 33 patients operated from April 2002 to September 2004 with the Bascom asymmetric cleft lift technique, we were able to contact 29 who were invited to a follow up study. Eighteen (62%) of these patients accepted a consultation in the outpatient clinic while 11 (38%) were interviewed by phone.

RESULTS

At follow up mean 17 (range 10-27) months after the operation 24 (83%) of the wounds were healed while recurrences were present in 5 (17%) of the patients. In two of the patients with recurrences errors in the procedures were identified. Further results related to pre-, per- and postoperative conditions are discussed in this paper.

CONCLUSION

Early results after surgery for PSD with the Bascom asymmetric cleft-lift technique are promising. The technique has now become our standard procedure for treating chronic, symptomatic PSD.

Growth hormone and insulinlike growth factor 1 promote intestinal uptake and hepatic release of glutamine in sepsis

OBJECTIVE

To study the effects of growth hormone (GH) and insulinlike growth factor 1 (IGF-1) on whole body and gastrointestinal (GI), hepatic, femoral, and renal glutamine (GLN) uptake and release in septic piglets.

SUMMARY BACKGROUND DATA

The GI metabolism of GLN is impaired during sepsis, and this may contribute to a breakdown of the gut's mucosal barrier. GH treatment has produced increased GI GLN uptake in surgical stress. Little is known about the effects of GH and IGF-1 in sepsis.

METHODS

Twenty-four piglets were randomized to three groups of eight each: a GH group received a bolus of 16 IU of Genotropin; an IGF-1 group received a continuous infusion of 1.3 mg/hour of IGF-1; and a control group received saline. After surgical preparation, sepsis was induced with live Escherichia coli bacteria. Using isotope technique, whole body turnover and organ-specific absolute uptake and release were measured before and 4 hours after sepsis.

RESULTS

After sepsis, both GH and IGF-1 treatment increased GI GLN uptake compared with controls and induced hepatic release of GLN. GLN release from skeletal muscle was diminished in all groups after sepsis. Whole body GLN turnover was increased in the GH and IGF-1 groups compared with the controls, before and after sepsis.

CONCLUSIONS

GH and IGF-1 treatment induced increased GI net uptake of GLN. GH and IGF-1 treatment also promoted absolute and net release of GLN from the liver. This release might facilitate increased GI uptake despite reduced hindleg release in the early phase of sepsis.

Fatal course in severe meningococcemia: clinical predictors and effect of transfusion therapy

OBJECTIVE

To investigate whether the administration of fresh-frozen plasma to patients with systemic meningococcal disease is associated with an increased mortality rate compared with the administration of plasma substitutes.

DESIGN

Seventeen-year case-control study.

SETTING

Intensive care units and departments of internal medicine and pediatrics of one university hospital and one local hospital.

PATIENTS

A total of 336 patients with culture-proven meningococcemia or symptoms characteristic of meningococcemia who were admitted to two hospitals in northern Norway between 1974 and 1991.

MEASUREMENTS AND MAIN RESULTS

High-risk patients were selected on the basis of two different scoring systems (Niklasson's score and clinical score) and classified according to the type of intravenous fluid regimen (fresh-frozen plasma, blood, or colloids). For comparison between groups, analysis of variance and chi-square tests were used. Assessments of adjusted effects on mortality rate were done by multiple logistic regression. Administration of blood or plasma was significantly associated with a fatal course, both in the total patient population (p < .01) and in the high-risk group (p = .02), while using colloids alone was negatively associated with death, although not reaching statistical significance. A significantly lower mortality rate was found in one of the hospitals where colloids were used instead of plasma or blood in the last part of the period studied (p < .05).

CONCLUSION

The results support our hypothesis that the use of fresh-frozen plasma may negatively influence outcome in systemic meningococcal disease.

Protein S-100beta: a biochemical marker for increased intracranial pressure in pigs with acute hepatic failure

BACKGROUND

Acute hepatic failure (AHF) may cause encephalopathy. Intracranial pressure (ICP) is frequently monitored to guide therapy, but such monitoring may cause intracerebral haemorrhagic complications. We hypothesize that determination of serum levels of S-100beta, a protein synthesized in astroglial cells, will provide useful clinical information on the presence and extent of intracranial hypertension in AHF.

METHODS

Continuous intraparenchymatous ICP monitoring and serial S-100beta measurements in serum were performed in 11 Norwegian Landrace pigs with surgically induced AHF and in 4 sham-operated controls.

RESULTS

ICP increased hour by hour in the devascularized pigs in parallel with increased serum levels of protein S-100beta. In the sham-operated controls S-100beta was not detectable at any time point.

CONCLUSIONS

Serum levels of S-100beta are increased early in experimental AHF. Determination of protein S-100beta may provide useful information on the presence and extent of intracranial hypertension in AHF.