Gastric intramucosal pH predicts death in severe acute pancreatitis

The Pathogenesis of Nonocclusive Mesenteric Ischemia: Implications for Research and Clinical Practice

Nonocclusive mesenteric ischemia (NOMI) is a condition that can encompass ischemia, inflammation, and infarction of the intestinal wall. In contrast to most patients with acute mesenteric ischemia, NOMI is distinguished by patent arteries and veins. The clinical presentation of NOMI is often insidious and nonspecific, resulting in a delayed diagnosis. Patients most at risk are those with severe acute and critical disease, including major surgery and trauma. Nonocclusive mesenteric ischemia is part of a spectrum, from mild, asymptomatic, and an unexpected finding on CT scanning, through to those exhibiting abdominal distension and peritonitis. Severe NOMI is associated with a significant mortality rate. This review of NOMI pathophysiology was conducted to document current concepts and evidence, to examine the implications for diagnosis and treatment, and to identify gaps in knowledge that might direct future research. The key pathologic mechanisms involved in the genesis of NOMI represent an exaggerated normal physiological response to maintain perfusion of vital organs at the expense of mesenteric perfusion. A supply-demand mismatch develops in the intestine due to the development of persistent mesenteric vasoconstriction resulting in reduced blood flow and oxygen delivery to the intestine, particularly to the vulnerable superficial mucosa. This mismatch can be exacerbated by raised intra-abdominal pressure, enteral nutrition, and the use of certain vasoactive drugs, ultimately resulting in the development of intestinal ischemia. Strategies for prevention, early detection, and treatment are urgently needed.

The anatomy and physiology of the terminal thoracic duct and ostial valve in health and disease: potential implications for intervention

The thoracic duct (TD) transports lymph drained from the body to the venous system in the neck via the lymphovenous junction. There has been increased interest in the TD lymph (including gut lymph) because of its putative role in the promotion of systemic inflammation and organ dysfunction during acute and critical illness. Minimally invasive TD cannulation has recently been described as a potential method to access TD lymph for investigation. However, marked anatomical variability exists in the terminal segment and the physiology regarding the ostial valve and terminal TD is poorly understood. A systematic review was conducted using three databases from 1909 until May 2017. Human and animal studies were included and data from surgical, radiological and cadaveric studies were retrieved. Sixty-three articles from the last 108 years were included in the analysis. The terminal TD exists as a single duct in its terminal course in 72% of cases and 13% have multiple terminations: double (8.5%), triple (1.8%) and quadruple (2.2%). The ostial valve functions to regulate flow in relation to the respiratory cycle. The patency of this valve found at the lymphovenous junction opening, is determined by venous wall tension. During inspiration, central venous pressure (CVP) falls and the valve cusps collapse to allow antegrade flow of lymph into the vein. During early expiration when CVP and venous wall tension rises, the ostial valve leaflets cover the opening of the lymphovenous junction preventing antegrade lymph flow. During chronic disease states associated with an elevated mean CVP (e.g. in heart failure or cirrhosis), there is a limitation of flow across the lymphovenous junction. Although lymph production is increased in both heart failure and cirrhosis, TD lymph outflow across the lymphovenous junction is unable to compensate for this increase. In conclusion the terminal TD shows marked anatomical variability and TD lymph flow is controlled at the ostial valve, which responds to changes in CVP. This information is relevant to techniques for cannulating the TD, with the aid of minimally invasive methods and high resolution ultrasonography, to enable longitudinal physiology and lymph composition studies in awake patients with both acute and chronic disease.

Acute pancreatitis conditioned mesenteric lymph causes cardiac dysfunction in rats independent of hypotension

BACKGROUND

Critical illness including severe acute pancreatitis is associated with the multiple organ dysfunction syndrome. The "gut-lymph" hypothesis states that multiple organ dysfunction syndrome is due to release of toxic factors from the intestine into the mesenteric lymph. The aims of this study were to determine the effect of normotensive acute pancreatitis conditioned mesenteric lymph on cardiac function and whether external drainage of mesenteric lymph would protect the heart.

METHODS

Groups of normal rats and those with normotensive taurocholate induced acute pancreatitis, had either no lymphatic intervention or thoracic duct ligation and external drainage of mesenteric lymph. After 6 hours, the hearts were removed for ex vivo functional measurements, including cardiac output, ventricular contractility (+dP/dt), and relaxation (-dP/dt). In a second experiment, mesenteric lymph from normal rats and those with established acute pancreatitis was infused into ex vivo perfused normal working rat hearts to assess impact on cardiac function. Heart and lung tissues were collected for assessment of edema.

RESULTS

Significant cardiac dysfunction, denoted by decreased cardiac output (21%), contractility (37%), relaxability (23%), and increased cardiac tissue edema (2-fold), developed in rats with established acute pancreatitis and no lymphatic intervention compared with the control group (all P < .05). Strikingly this cardiac dysfunction and edema was normalized in acute pancreatitis rats that had undergone prior thoracic duct ligation and external drainage of mesenteric lymph. In the second experiment, infusion of acute pancreatitis conditioned mesenteric lymph resulted in an immediate and significant similar magnitude decrease in of cardiac output (17%), contractility (22%), and relaxation (27%) compared with the infusion of normal lymph (all P <.05).

CONCLUSION

Mesenteric lymph from normotensive acute pancreatitis animals caused significant cardiac dysfunction which could be prevented by thoracic duct ligation and external drainage of mesenteric lymph.

Novel strategies for the treatment of acute pancreatitis based on the determinants of severity

Acute pancreatitis (AP) is a common disease for which a specific treatment remains elusive. The key determinants of the outcome from AP are persistent organ failure and infected pancreatic necrosis. The prevention and treatment of these determinants provides a framework for the development of specific treatment strategies. The gut-lymph concept provides a common mechanism for systemic inflammation and organ dysfunction. Acute and critical illness, including AP, is associated with intestinal ischemia and drastic changes in the composition of gut lymph, which bypasses the liver to drain into the systemic circulation immediately proximal to the major organ systems which fail. The external diversion of gut lymph and the targeting of treatments to counter the toxic elements in gut lymph offers novel approaches to the prevention and treatment of persistent organ failure. Infected pancreatic necrosis is increasingly treated with less invasive techniques, the mainstay of which is drainage, both endoscopic and percutaneous. Further improvements will occur with the strategies to accelerate liquefaction and through a fundamental re-design of drains, both of which will increase drainage efficacy. The determinants of severity and outcome in patients admitted with AP provide the basis for innovative treatment strategies. The priorities are to translate the gut-lymph concept to clinical practice and to improve the design and active use of drains for infected complications of AP.

Functional testing in the diagnosis of chronic mesenteric ischemia

Chronic mesenteric ischemia (CMI) results from insufficient oxygen delivery or utilization to meet metabolic demand. Two main mechanisms may lead to mesenteric ischemia: occlusion in the arteries or veins of the gastrointestinal tract, or reduced blood flow from shock states or increased intra-abdominal pressure, so-called non-occlusive mesenteric ischemia. Severe stenoses in the three main mesenteric vessels as demonstrated with CT-angiography or MR-angiography are sufficient to proof mesenteric ischemia, for example in patients who present with weight loss, postprandial pain and diarrhea. Still in many clinical situations mesenteric ischemia is only one of many possible explanations. Especially in patients with a single vessel stenosis in the celiac artery or superior mesenteric artery with postprandial pain, mesenteric ischemia remains a diagnosis of probability or assumption without functional proof of actual ischemia. This review is aimed to provide an overview of all past, present and future ways to functionally proof CMI.

Role of liver in modulating the release of inflammatory cytokines involved in lung and multiple organ dysfunction in severe acute pancreatitis

The objective of this study was to understand the role of liver in modulating remote organ dysfunction during severe acute pancreatitis (SAP). We used sodium taurocholate and endotoxin to induce SAP in the rats and confirmed the development of this condition by measuring serum and ascite levels of the biomarkers of liver and lung damage. Our results showed that expression of tumor necrosis factor (TNF)-α was up-regulated sequentially, first in the gut, then in the liver, and finally in lung. Moreover, the SAP-induced increase in the expressions of TNF-α and IL-6 occurring in gut, liver, and lung was directly related to the increase in time. However, in liver and lung, the transcriptional activity of NF-κB and expression of TNF-α at 4 and 8 h were not increased. The distribution sequence of the pro-inflammatory cytokines to various organs was determined by their detection in the blood from portal vein and inferior vena cava. Although liver received TNF-α during 0.5-8 h of the SAP induction, the release of this cytokine into vena cava was not increased in this period of time. In conclusion, our results suggest that the aggravation of SAP leading to development of MODS exhibited the gut-liver-lung cytokine axis. Furthermore, this study indicates that liver performs both protective and stimulatory activities in the modulation of pro-inflammatory cytokine generation and their distribution to remote organs, such as lungs.

Fluid resuscitation in sepsis: reexamining the paradigm

Sepsis results in widespread inflammatory responses altering homeostasis. Associated circulatory abnormalities (peripheral vasodilation, intravascular volume depletion, increased cellular metabolism, and myocardial depression) lead to an imbalance between oxygen delivery and demand, triggering end organ injury and failure. Fluid resuscitation is a key part of treatment, but there is little agreement on choice, amount, and end points for fluid resuscitation. Over the past few years, the safety of some fluid preparations has been questioned. Our paper highlights current concerns, reviews the science behind current practices, and aims to clarify some of the controversies surrounding fluid resuscitation in sepsis.

Protective effect of hydrogen sulfide against cold restraint stress-induced gastric mucosal injury in rats

Hydrogen sulfide (H2S) is an endogenous gaseous mediator plays a potential role in modulating gastric inflammatory responses. However, its putative protective role remains to be defined. The present study aimed to evaluate role of the exogenously released and endogenously synthesized H2S in cold restraint stress (CRS)-induced oxidative gastric damage in rats. Rats were restrained, and maintained at 4 °C for 3 h. The H2S donor, sodium hydrosulfide (NaHS) (60 μmol/kg) was injected intraperitoneally (i.p.) before CRS. Our results revealed that NaHS pretreatment significantly attenuated ulcer index, free and total acid output, and pepsin activity in gastric juice along with decreased gastric mucosal carbonyl content and reactive oxygen species production. This was accompanied by increased gastric juice pH and mucin concentration in addition to restoring the deficits in the gastric reduced glutathione, catalase as well as superoxide dismutase enzyme activities. NaHS pretreatment markedly reduced the serum level of tumor necrosis factor (TNF-α) and myeloperoxidase activity compared to CRS-non-treated. Moreover, NaHS preadministration significantly abrogated the inflammatory and the deleterious responses of gastric mucosa in CRS. The protective effects of H2S were confirmed by gastric histopathological examination. However, pretreatment with the H2S-synthesizing enzyme, cystathionine-gamma-lyase inhibitor, beta-cyano-L-alanine (50 mg/kg, i.p.) reversed the gastroprotection afforded by the endogenous H2S. Collectively, our results suggest that H2S can protect rat gastric mucosa against CRS-induced gastric ulceration possibly through mechanisms that involve anti-oxidant and anti-inflammatory actions alongside enhancement of gastric mucosal barrier and reduction in acid secretory parameters.

Pathophysiology of acute pancreatitis: potential application from experimental models and human medicine to dogs

The cellular events leading to pancreatitis have been studied extensively in experimental models. Understanding the cellular events and inciting causes of the multisystem inflammatory cascades that are activated with this disease is of vital importance to advance diagnosis and treatment of this condition. Unfortunately, the pathophysiology of pancreatitis in dogs is not well understood, and extrapolation from experimental and human medicine is necessary. The interplay of the inflammatory cascades (kinin, complement, cytokine) is extremely complex in both initiating leukocyte migration and perpetuating disease. Recently, nitric oxide (NO) and altered microcirculation of the pancreas have been proposed as major initiators of inflammation. In addition, the role of the gut is becoming increasingly explored as a cause of oxidative stress and potentiation of systemic inflammation in pancreatitis.

Acute pancreatitis severity is exacerbated by intestinal ischemia-reperfusion conditioned mesenteric lymph

OBJECTIVE

To determine the effect of intestinal ischemia-reperfusion (IIR) on acute pancreatitis (AP) and the role of mesenteric lymph.

SUMMARY BACKGROUND DATA

Intestinal ischemia is an early feature of AP and is related to the severity of disease. It is not known whether this contributes to the severity of AP or is a consequence.

METHODS

Two experiments are reported here using intravital microscopy and a rodent model of mild acute pancreatitis (intraductal 2.5% sodium taurocholate). In the first, rats had an episode of IIR during AP that was produced by temporary occlusion of the superior mesenteric artery (30 min or 3 x 10 min) followed by 2h reperfusion. In a second study rats with AP had an intravenous infusion of mesenteric lymph collected from donor rats that had been subjected to IIR. In both experiments the pancreatic erythrocyte velocity (EV), functional capillary density (FCD), leukocyte adherence (LA), histology and edema index were measured.

RESULTS

The addition of IIR to AP caused a decline in the pancreatic microcirculation greater than that of AP alone (EV 42% of baseline vs. 73% of baseline AP alone, FCD 43% vs 72%, LA 7 fold increase vs 4 fold increase). This caused an increased severity of AP as evidenced by 1.4-1.8 fold increase of pancreatic edema index and histologic injury respectively. A very similar exacerbation of microvascular failure and increased pancreatitis severity was then demonstrated by the intravenous infusion of IIR conditioned mesenteric lymph from donor animals.

CONCLUSIONS

Unidentified factors released into the mesenteric lymph following IIR injury are capable of exacerbating AP. This highlights an important role for the intestine in the pathophysiology of AP pathogenesis and identifies mesenteric lymph as a potential therapeutic target.

Severe acute pancreatitis: Clinical course and management

Severe acute pancreatitis (SAP) develops in about 25% of patients with acute pancreatitis (AP). Severity of AP is linked to the presence of systemic organ dysfunctions and/or necrotizing pancreatitis pathomorphologically. Risk factors determining independently the outcome of SAP are early multi-organ failure, infection of necrosis and extended necrosis (> 50%). Up to one third of patients with necrotizing pancreatitis develop in the late course infection of necroses. Morbidity of SAP is biphasic, in the first week strongly related to early and persistence of organ or multi-organ dysfunction. Clinical sepsis caused by infected necrosis leading to multi-organ failure syndrome (MOFS) occurs in the later course after the first week. To predict sepsis, MOFS or deaths in the first 48-72 h, the highest predictive accuracy has been objectified for procalcitonin and IL-8; the Sepsis-Related Organ Failure Assessment (SOFA)-score predicts the outcome in the first 48 h, and provides a daily assessment of treatment response with a high positive predictive value. Contrast-enhanced CT provides the highest diagnostic accuracy for necrotizing pancreatitis when performed after the first week of disease. Patients who suffer early organ dysfunctions or at risk of developing a severe disease require early intensive care treatment. Early vigorous intravenous fluid replacement is of foremost importance. The goal is to decrease the hematocrit or restore normal cardiocirculatory functions. Antibiotic prophylaxis has not been shown as an effective preventive treatment. Early enteral feeding is based on a high level of evidence, resulting in a reduction of local and systemic infection. Patients suffering infected necrosis causing clinical sepsis, pancreatic abscess or surgical acute abdomen are candidates for early intervention. Hospital mortality of SAP after interventional or surgical debridement has decreased in high volume centers to below 20%.

Diagnostic criteria and severity assessment of acute cholecystitis: Tokyo Guidelines

This article addresses the criteria for severity assessment and the severity scoring system of the Ministry of Health and Welfare of Japan; now the Japanese Ministry of Health, Labour, and Welfare (the JPN score). It also presents data comparing the JPN score with the Acute Physiology and Chronic Health Evaluation (APACHE) II score and the Ranson score, which are the major measuring scales used in the United States and Europe. The goal of investigating these scoring systems is the achievement of earlier diagnosis and more appropriate and successful treatment of severe or moderate acute pancreatitis, which has a high mortality rate. This article makes the following recommendations in terms of assessing the severity of acute pancreatitis:

(1) Severity assessment is indispensable to the selection of proper initial treatment in the management of acute pancreatitis (Recommendation A).

(2) Assessment by a severity scoring system (JPN score, APACHE II score) is important for determining treatment policy and identifying the need for transfer to a specialist unit (Recommendation A).

(3) C-reactive protein (CRP) is a useful indicator for assessing severity (Recommendation A).

(4) Contrast-enhanced computed tomography (CT) scanning and contrast-enhanced magnetic resonance imaging (MRI) play an important role in severity assessment (Recommendation A).

(5) A JPN score of 2 or more (severe acute pancreatitis) has been established as the criterion for hospital transfer (Recommendation A).

(6) It is preferable to transfer patients with severe acute pancreatitis to a specialist medical institution where they can receive continuous monitoring and systemic management.

Prolonged intestinal mucosal acidosis is associated with multiple organ failure in human acute pancreatitis: Gastric tonometry revisited

AIM: To evaluate whether multiple determinations of intramucosal pH (pHi) in acute pancreatitis (AP) patients could provide additional information of the disease severity during early hospitalization.

METHODS: Twenty-one patients suffering from acute pancreatitis were monitored by gastric tonometry in the first 72 h after hospital admission.

RESULTS: In the survivor group (n = 15) the initially low pHi values returned to normal level (pHi ≥ 7.32) within 48 h (median pHi: d 1: 7.21; d 2: 7.32; d 3: 7.33). In contrast, pHi values in the non-survivor group n = 6) were persistently either below or in the low normal range (median pHi 7.12; 7.12; 7.07 respectively), but pHi differences between the two groups reached significance only after 24 h (P < 0.01). Mucosal acidosis detected at any time during the monitored period was associated with the emergence of single or multiple organ dysfunction (P < 0.01).

CONCLUSION: Prolonged gastric mucosal acidosis was associated with remote organ dysfunction and failure in Acute Pancreatitis, however, correlation with the fatal outcome became significant only 24 h after admission. Due to its non-invasive nature gastric tonometry may supplement the pro-inflammatory markers to achieve a multi-faceted monitoring of the disease.

Clinical laboratory assessment of acute pancreatitis

BACKGROUND

Several biochemical markers in blood and urine have been investigated to establish their clinical application in patients with acute pancreatitis (AP). The relevant studies are reviewed and critically appraised.

METHODS

Medline and the World Wide Web were searched and the relevant literature was classified under the following categories: (1) diagnosis of AP and (2) prediction of: a) disease severity, b) pancreatic necrosis and its secondary infection, c) organ failure and death, and d) disease etiology.

RESULTS AND CONCLUSIONS

Serum lipase is a more reliable diagnostic marker of AP than serum amylase. Urinary strip tests for trypsinogen activation peptide (TAP) and trypsinogen-2 provide a reliable early diagnosis of AP. Useful predictors of severity may include serum procalcitonin and urinary TAP and trypsinogen-2 on admission, serum interleukins-6 and -8 and polymorphonuclear elastase at 24 h, and serum C-reactive protein (CRP) at 48 h. Other markers such as amyloid A and carboxypeptidase B activation peptide (CAPAP) need further investigation. Biochemical prediction of pancreatic necrosis requires 72 h to reach reliability and is impractical. However, the daily monitoring of serum procalcitonin provides a non-invasive detection of infected necrosis; the promising role of phospholipase A(2) in this regard requires further investigation. Early transient hypertransaminasemia reliably predicts biliary etiology, while serum carbohydrate-deficient transferrin and trypsin may predict an alcoholic etiology.

Role of the gut in the course of severe acute pancreatitis

INTRODUCTION

The pathogenesis of acute pancreatitis remains elusive. Sepsis and multiple organ failure continue to cause death (overall mortality rate, approximately 10%) despite immense improvements in supportive, radiologic, and surgical therapy. The gut appears to play a key role in the development of these complications.

AIM

To critically review the evidence implicating the gut in the pathogenesis of acute pancreatitis.

METHODS

Relevant English-language literature or abstracts cited in the MEDLINE database were reviewed.

RESULTS AND CONCLUSION

Gram-negative enteric organisms account for most infections of pancreatic necrosis and subsequent sepsis, which suggests the gut as a source. Intestinal permeability is increased early in patients with severe acute pancreatitis and correlates with endotoxemia, which suggests translocation as a possible mechanism. The pathogenesis of the deranged function of the gut mucosal barrier and the possible sites of increase in intestinal permeability are discussed. The gut also plays a role in priming neutrophils and the release of inflammatory cytokines, which initiate and propagate nearly all the detrimental consequences of severe inflammation and sepsis. Future research avenues and potential therapeutic measures that may restore and preserve gut barrier function are explored.

The role of the intestine in the pathophysiology and management of severe acute pancreatitis

BACKGROUND

The outcome of severe acute pancreatitis has scarcely improved in 10 years. Further impact will require new paradigms in pathophysiology and treatment. There is accumulating evidence to support the concept that the intestine has a key role in the pathophysiology of severe acute pancreatitis which goes beyond the notion of secondary pancreatic infection. Intestinal ischaemia and reperfusion and barrier failure are implicated in the development of multiple organ failure.

DISCUSSION

Conventional management of severe acute pancreatitis has tended to ignore the intestine. More recent attempts to rectify this problem have included 1) resuscitation aimed at restoring intestinal blood flow through the use of appropriate fluids and splanchnic-sparing vasoconstrictors or inotropes; 2) enteral nutrition to help maintain the integrity of the intestinal barrier; 3) selective gut decontamination and prophylactic antibiotics to reduce bacterial translocation and secondary infection. Novel therapies are being developed to limit intestinal injury, and these include antioxidants and anti-cytokine agents. This paper focuses on the role of the intestine in the pathogenesis of severe acute pancreatitis and reviews the implications for management.

Plasma amylin concentration is related to the severity of intestinal ischemic injury in rats

BACKGROUND

Previous work has demonstrated that intestinal ischemia increases plasma amylin concentration. This study examined the relationship between the degree of intestinal ischemia injury and plasma amylin in an experimental rat model.

METHODS

Wistar rats were divided into a control group (n = 6); a sham-operated group (n = 9); and 3 intestinal ischemia-reperfusion groups (n = 8 in each), which underwent clamping of the superior mesenteric artery for either 15, 30, or 45 minutes followed by 15 minutes of reperfusion. Samples were then collected for intestinal histology and measurement of amylin, insulin, and glucose.

RESULTS

There was a positive correlation between the histologic score of the intestinal injury and the measured plasma amylin concentration (R = 0.48, P =.007). The median plasma concentration of amylin was 62 pmol/L (range, 42-97 pmol/L) in the 30-minute intestinal ischemia group and 58 pmol/L (42-86 pmol/L) in the 45-minute intestinal ischemia group. Both these groups were increased compared with the sham-operated group (29 pmol/L; range, 22-57 pmol/L; P <.001 and P <.005, respectively) and the control group (28 pmol/L; range, 26-42 pmol/L; P <.001 and P <.0005, respectively). The median plasma concentration of insulin in the 30-minute intestinal ischemia group was 4230 pmol/L (range, 1360-5770 pmol/L), which was increased compared with both the control group (950 pmol/L; range, 550-1510 pmol/L; P <.005) and the sham-operated group (720 pmol/L; range, 280-4180 pmol/L; P<.005). There were no differences between any of the other groups either for glucose, insulin, or amylin.

CONCLUSIONS

Plasma amylin concentration is related to the severity of intestinal ischemic injury.

Gastric tonometry in patients with cardiogenic shock and intra-aortic balloon counterpulsation

OBJECTIVE

To study the course of gastric regional PCO2 (PrCO2) in patients with cardiogenic shock requiring intra-aortic balloon (IAB) counterpulsation and the prognostic value of PrCO2 in this patient population.

DESIGN

A prospective, observational clinical study.

SETTING

Medical intensive care unit in a university hospital.

PATIENTS

Twenty-six consecutive patients with cardiogenic shock requiring mechanical support with an IAB counterpulsation undergoing mechanical ventilation

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULT

Hemodynamic variables, tonometric variables, arterial blood gases, and arterial lactate were assessed before insertion of IAB (baseline), and 1, 2, 3, 8, 16, 24, and 48 hrs thereafter. A subset of these patients (n = 14) were studied just before and 1, 8, 24, and 32 hrs after IAB removal; 12/26 patients (46.2%) died. Cardiac index increased from baseline to 1 hr after insertion of IAB (1.7 +/- 0.3 to 2.6 +/- 0.8 L/min/m2, p < .05). PrCO2 did not change between admission (47 +/- 13 torr [6.3 +/- 1.7 kPa]) and 8 hrs after placement of IAB but increased to 63 +/- 22 torr (8.4 +/- 2.9 kPa) at 16 hrs (p < .05) without any further alteration until 48 hrs. CO2 gap showed a similar pattern with 15 +/- 11 torr (2.0 +/- 1.5 kPa) at baseline and an increase to 28 +/- 22 torr (3.7 +/- 2.9 kPa) 16 hrs later. PrCO2 and CO2 gap remained at high levels (59 +/- 11 torr [7.7 +/- 1.5 kPa] and 22 +/- 10 torr [2.9 +/- 1.3 kPa], respectively), before IAB removal without further improvement or deterioration thereafter. PrCO2 values showed no difference between survivors and nonsurvivors at any time point.

CONCLUSION

Patients with cardiogenic shock developed high PrCO2 within the first 24 hrs, which reflects gastric mucosal ischemia. Persistently high levels of PrCO2 were indicative for prolonged hypoperfusion of the gut. Gastric tonometry failed to discriminate between survivors and nonsurvivors.

Gastric tonometry in assessing splanchnic tissue perfusion in acute pancreatitis

BACKGROUND

Hypovolemia is typical early in acute pancreatitis. Despite fluid resuscitation splanchnic hypoperfusion may be present and may have a role in the course of pancreatitis. To test this hypothesis, we assessed gastric mucosal pH (pHi) and P(CO)2 during the first 48 h of hospitalization for acute pancreatitis.

METHODS

Thirty-three patients were studied. A gastric tonometer was inserted on admission, and gastric mucosal pH and P(CO)2 were measured on admission and then every 12 h during next 48 h.

RESULTS

On the basis of the Atlanta classification there were 22 cases of mild and 8 of severe pancreatitis. Three patients were excluded because of consent withdrawal. The groups were similar with regard to age, sex ratio, and etiology of pancreatitis. Independently of disease severity the gastric pHi decreased, and the gastric mucosal-arterial P(CO)2 difference and pH difference both increased over time as compared with base line. No difference was seen in these values between mild and severe pancreatitis.

CONCLUSIONS

Moderate gastric mucosal hypoperfusion was found early in acute pancreatitis. However, gastric pHi measurement with tonometry has no obvious value as a screening tool to assess the severity of pancreatitis.

Plasma von Willebrand factor and intestinal ischaemia-reperfusion injury in rats

The purpose of this study was to determine whether plasma von Willebrand factor concentrations are correlated with the degree of intestinal ischaemia-reperfusion injury. Forty-six anaesthetised adult Wistar rats were divided into five groups. The sham-operated group (S, n=10) had laparotomy and isolation of the superior mesenteric artery without clamping. Three ischaemia-reperfusion groups (n=10 in each) had clamping of the superior mesenteric artery for 15, 30, and 45 minutes, respectively, and reperfusion for 15 minutes. A control group (C, n=6) had direct puncture of the heart to sample blood. Mean arterial pressure was measured continuously. Blood was collected at the end of the study to measure von Willebrand factor. The small bowel injury was graded histologically. There was a significant systemic hypotension after declamping in all ischaemia-reperfusion groups, which had a high negative correlation with the histological score (R=-0.46, F=10.1, p<0.003, simple linear regression). Plasma von Willebrand factor was significantly elevated in the three ischaemia-reperfusion groups compared with the control group but not significantly different from the sham-operated group (mean von Willebrand factor concentration (SEM): 156 (29), 283 (29), 295 (25), 381 (44), and 366 (40)% in C, S, ischaemia-reperfusion 15, ischaemia-reperfusion 30, and ischaemia-reperfusion 45 groups, respectively). The concentration of von Willebrand factor was not correlated to the histological score (R=0.22, F=1.83, p<0.2) or the degree of hypotension after the removal of the clamp (R=-0.22, F=1.8, p<0.2, simple linear regression). This study shows that von Willebrand factor concentration does not correlate with the degree of intestinal ischaemia-reperfusion injury. It is unlikely that von Willebrand factor can be used as a predictor of disease severity.

Splanchnic tissue perfusion in acute experimental pancreatitis

BACKGROUND

Gut hypoperfusion may have a role in the pathogenesis of multiple organ failure, which is a the main cause of death in severe acute pancreatitis. We hypothesized that gut hypoperfusion is present early in acute pancreatitis and that supporting the systemic hemodynamics by fluid resuscitation would prevent this.

METHODS

In a pig model of randomized, controlled experimental hemorrhagic pancreatitis induced by Na-taurocholate the animals were divided into four groups (n = 6 for each): 1) pancreatitis, 2) control, 3) pancreatitis and fluid resuscitation to keep the pulmonary capillary wedge pressure at 5 to 6 mmHg, and 4) control and fluid resuscitation as in group 3. Splanchnic perfusion was assessed by means of local PCO2 gap with intestinal tonometer, oxygen delivery and consumption, lactate production, and blood flow. The follow-up time was 6 h.

RESULTS

The Pco2 gap increased in pancreatitis (1.72+/-0.17, 1.94+/-0.29, 1.75+/-0.22, 2.32+/-0.33; 9.40+/-2.16, 3.72+/-1.78, 0.84+/-0.39, 1.11+/-0.21 kPa, respectively; P < 0.05). Oxygen delivery in portal-drained organs decreased in pancreatitis (2.5+/-0.3, 2.6+/-0.2, 2.8+/-0.4, 2.3+/-0.2; 1.7+/-0.3, 2.3+/-0.3, 2.4+/-0.5, 2.3+/-0.3 ml/min x kg, respectively; P < 0.05). Regional oxygen consumption did not change. Arterial plasma lactate increased (1.20+/-0.19, 1.33+/-0.16, 1.14+/-0.15, 1.43+/-0.33; 3.81+/-1.31, 1.48+/-0.48, 1.12+/-0.18, 1.18+/-0.35 mmol/l, respectively; P < 0.05). The portal venous blood flow decreased 50% in pancreatitis, but with fluid resuscitation it increased 50%.

CONCLUSIONS

Splanchnic hypoperfusion is present early in acute hemorrhagic pancreatitis. The signs of hypoperfusion can be prevented with fluid resuscitation.