Predicting complicated appendicitis based on clinical findings: the role of Alvarado and Appendicitis Inflammatory Response scores.

PURPOSE: The pre-interventional differentiation between complicated and uncomplicated appendicitis is decisive for treatment. In the context of conservative therapy, the definitive diagnosis of uncomplicated appendicitis is mandatory. This study investigates the ability of clinical scoring systems and imaging to differentiate between the two entities. METHODS: This is a retrospective analysis of two cohorts from two tertiary referral centers in Switzerland and Germany. All consecutive patients underwent appendectomy between January 2008 and April 2013 (in the first cohort) or between January 2017 and June 2019 (the second cohort). Exclusion criteria did not apply as all patients found by the database search and received an appendectomy were included. Diagnostic testing and calculation of a receiver operating curve were performed to identify a cutoff for clinical scores that resulted in a minimum sensitivity of 90% to detect complicated appendicitis. The cutoff was combined with additional diagnostic imaging criteria to see if diagnostic properties could be improved. RESULTS: Nine hundred fifty-six patients were included in the analysis. Two hundred twenty patients (23%) had complicated appendicitis, and 736 patients (77%) had uncomplicated appendicitis or no inflammation. The complicated appendicitis cohort had a mean Alvarado score of 7.03 and a mean AIR of 5.21. This compared to a mean Alvarado of 6.53 and a mean AIR of 4.07 for the uncomplicated appendicitis cohort. The highest Alvarado score with a sensitivity of > 90% to detect complicated appendicitis was ≧ 5 (sensitivity = 95%, specificity 8.99%). The highest AIR score with a sensitivity of > 90% to detect complicated appendicitis was ≧ 3 (sensitivity 91.82%, specificity 18.53). The analysis showed that additional CT information did not improve the sensitivity of the proposed cut-offs. CONCLUSION: AIR and Alvarado scores showed limited capability to distinguish between complicated and uncomplicated appendicitis even with additional imaging in this retrospective cohort. As conservative management of appendicitis needs to exclude patients with complicated disease reliably, appendectomy seems until now to remain the safest option to prevent undertreatment of this mostly benign disease.

Oral health-related quality of life of patients after solid organ transplantation is not affected by oral conditions: results of a multicentre cross-sectional study.

BACKGROUND: This multicentre cross-sectional study aimed in examination of oral health-related quality of life (OHRQoL) of patients after solid organ transplantation (SOT). MATERIAL AND METHODS: Patients after SOT (liver, lung and heart) at one out of three German centers (Goettingen, Essen, Leipzig) were included. For comparison, a healthy control (HC) was recruited. OHRQoL was assessed by German short form of oral health impact profile (OHIP G14). Oral examination comprised: decayed-, missing- and filled-teeth index (DMF-T), remaining teeth and periodontitis severity. RESULTS: In total, 196 patients after SOT and 130 HC with comparable age, gender and smoking habits were included (p>0.05). DMF-T and number of remaining teeth was worse in SOT group (p<0.01). OHIP G14 sum score was significantly higher in SOT (3.49 ± 5.73 vs. 1.33 ± 2.63, p<0.01). In contrast to HC, in SOT no associations between OHIP G14 and oral health parameters were found (pi>0.05). Number of remaining teeth was not an independent predictor of OHIP G14 sum score in SOT (ß -0.082, CI95 -0.156 - 0.045, p=0.28). CONCLUSIONS: OHRQoL of SOT recipients is not affected by their oral condition, leading to the assumption that the individual perception of patients physical oral health is not in line with the clinical situation.

[Is acute appendicitis a surgical emergency?] / Ist die akute Appendizitis ein chirurgischer Notfall?

Acute appendicitis is one of the most common causes of acute abdomen. Whereas patients with a complicated form of appendicitis need prompt surgery, short preoperative delays are tolerable for patients with uncomplicated appendicitis. Delays of up to 8 h between hospital admission and beginning of surgery are not associated with increased rates of perforation or postoperative complications.

Association of time under immunosuppression and different immunosuppressive medication on periodontal parameters and selected bacteria of patients after solid organ transplantation.

BACKGROUND: Aim of this study was to investigate the association of the time under immunosuppression and different immunosuppressive medication on periodontal parameters and selected periodontal pathogenic bacteria of immunosuppressed patients after solid organ transplantation (SOT). MATERIAL AND METHODS: 169 Patients after SOT (lung, liver or kidney) were included and divided into subgroups according their time under (0-1, 1-3, 3-6, 6-10 and >10 years) and form of immunosuppression (Tacrolimus, Cyclosporine, Mycophenolate, Glucocorticoids, Sirolimus and monotherapy vs. combination). Periodontal probing depth (PPD) and clinical attachment loss (CAL) were assessed. Periodontal disease severity was classified as healthy/mild, moderate or severe periodontitis. Subgingival biofilm samples were investigated for eleven selected potentially periodontal pathogenic bacteria using polymerasechainreaction. RESULTS: The mean PPD and CAL as well as prevalence of Treponema denticola and Capnocytophaga species was shown to be different but heterogeneous depending on time under immunosuppression (p<0.05). Furthermore, only the medication with Cyclosporine was found to show worse periodontal condition compared to patients without Cyclosporine (p<0.05). Prevalence of Porphyromonas gingivalis, Tannerella forsythia and Fusobacterium nucleatum was reduced and prevalence of Parvimonas micra and Capnocytophaga species was increased in patients under immunosuppression with Glucocorticoids, Mycophenolate as well as combination therapy. CONCLUSION: Time under and form of immunosuppression might have an impact on the clinical periodontal and microbiological parameters of patients after SOT. Patients under Cyclosporine medication should receive increased attention. Differences in subgingival biofilm, but not in clinical parameters were found for Glucocorticoids, Mycophenolate and combination therapy, making the clinical relevance of this finding unclear.

[Management of acute appendicitis : Evidence for prompt surgical treatment?] / Management der akuten Appendizitis : Evidenz für eine zeitnahe chirurgische Therapie?

BACKGROUND: Acute appendicitis is a common disease which requires immediate surgical treatment of the focus of inflammation. So far there are no reliable data on how much time can pass between hospitalization, indications for surgery and initiating surgery without an increased risk of morbidity and mortality for the patient. OBJECTIVE: The aim of this study was to investigate how much time can lapse between admission and initiation of surgery for acute appendicitis while still providing patient safety and no increase in complication rates. MATERIAL AND METHODS: This retrospective analysis investigated the management of all patients who underwent appendectomy under the suspicion of acute appendicitis. Besides the time span between hospital admittance and beginning of the operation (admission to incision time, AIT), anamnestic, diagnostic, technical and perioperative data were assessed and statistically analyzed (mean ± SD). RESULTS: From January 2008 to April 2013 a total of 655 patients underwent appendectomy. The mean AIT was 7 h and the rate of negative appendectomy was 9.8 %. The mean hospitalization period was 5.9 ± 8.7 days with a postoperative stay of 5.2 ± 7.1 days. A comparison of the subgroups stratified by increasing AIT showed that there was no increased probability for perforation or postoperative complications with an AIT of up to 8 h. DISCUSSION: This retrospective cohort study showed that appendectomy should be performed within the first 8 h after hospitalization of the patient.

Oral health-related quality of life in patients on chronic haemodialysis and after kidney transplantation.

OBJECTIVES: The objective of the study was to evaluate oral health-related quality of life (OHRQoL) depending on dental and periodontal situation in patients on haemodialysis (HD) and after kidney transplantation (KTx) compared to healthy controls (HC). SUBJECTS AND METHODS: OHRQoL was assessed using the German short form of Oral Health Impact Profile (OHIP G14). Dental health was estimated using the decayed, missing and filled teeth index (DMF-T). Periodontal health was classified as healthy/mild or moderate/severe periodontitis. STATISTICAL ANALYSIS: Mann-Whitney U-test, Kruskal-Wallis test, chi-square test and Fisher's test. RESULTS: Eighty-seven HD patients, 39 KTx patients and 91 HC were included. Significant differences in DMF-T, D-T, M-T and F-T scores were identified between groups (P < 0.001). The prevalence of moderate/severe periodontitis was significantly higher in the HD and KTx group compared to HC (P = 0.002). Differences in OHIP G14 between groups were neither clinical relevant nor statistically significant (P = 0.199). A significant effect of DMF-T (P = 0.012), M-T (P < 0.001) and periodontitis (P = 0.023) on the OHIP G14 scores was identified only in HC. CONCLUSIONS: Improvement in dental care of HD and KTx patients is required. OHIP G14 values provide a subjectively considered low importance of oral health in HD and KTx patients, leading to need of motivation and sensitisation of these patients.

Proangiogenic potency of MUC18 in arteriosclerotic disease.

AIM: Stenotic peripheral and dilatative arteriosclerotic diseases have different pathomechanism although associations between both diseases are well known. The adhesion molecule MUC18 is a cell membrane glycoprotein also known as the melanoma cell adhesion molecule. As MUC18 has proangiogenic potency in melanoma and prostate cancer this study investigated the role of MUC18 in patients with stenotic or dilatative arteriosclerotic disease as a putative biochemical marker. METHODS: Using qRT-PCR, Western Blot and immunohistochemistry techniques, the expression of MUC18 in arteriosclerotic arteries from major lower limb amputates (AP, N.=15) as well as specimen from femoral endarterectomies (TEA, N.=20) and in dilatative aortic diseases using abdominal aortic aneurysms (AAA, N.=13) was evaluated. Human visceral arteries without macroscopic arteriosclerosis from liver transplants served as controls (AN, N.=19). RESULTS: MUC18 mRNA and protein expression could be found in AN, AP, TEA and AAA tissues. Immunohistochemical analysis showed that a complete and intact intima was the predominant location of MUC18 expression. Although in stenotic arteriosclerotic disease (AP and TEA) the intima was widely calcified, qRT-PCR analysis showed overexpression compared to normal tissue. Interestingly, MUC18 expression was significantly down-regulated in dilatative compared to stenotic arteriosclerotic disease and normal arteries. CONCLUSION: In peripheral stenotic arteriosclerotic disease the proangiogenic potency of MUC18 may play a role in angiogenesis of collaterals, whereas in dilatative aortic diseases the induction of collaterals is typically not evident. The results support the hypothesis of a role in angiogenesis of MUC18 in stenotic arteriosclerotic disease.

Improved survival in liver transplant recipients receiving prolonged-release tacrolimus in the European Liver Transplant Registry.

This study was a retrospective analysis of the European Liver Transplant Registry (ELTR) performed to compare long-term outcomes with prolonged-release tacrolimus versus tacrolimus BD in liver transplantation (January 2008-December 2012). Clinical efficacy measures included univariate and multivariate analyses of risk factors influencing graft and patient survival at 3 years posttransplant. Efficacy measures were repeated using propensity score-matching for baseline demographics. Patients with <1 month of follow-up were excluded from the analyses. In total, 4367 patients (prolonged-release tacrolimus: n = 528; BD: n = 3839) from 21 European centers were included. Tacrolimus BD treatment was significantly associated with inferior graft (risk ratio: 1.81; p = 0.001) and patient survival (risk ratio: 1.72; p = 0.004) in multivariate analyses. Similar analyses performed on the propensity score-matched patients confirmed the significant survival advantages observed in the prolonged-release tacrolimus- versus tacrolimus BD-treated group. This large retrospective analysis from the ELTR identified significant improvements in long-term graft and patient survival in patients treated with prolonged-release tacrolimus versus tacrolimus BD in primary liver transplant recipients over 3 years of treatment. However, as with any retrospective registry evaluation, there are a number of limitations that should be considered when interpreting these data.

[Advance Directives - Not a Lot of Margin for Error - The Surgeon's View of a Complex Medical-Legal Topic]. / Patientenverfügungen - welchen Spielraum erlauben sie? - Chirurgische Sicht auf ein komplexes medizinjuristisches Thema.

Since September 1st, 2009, the most recent version of the German "Betreuungsrechtsänderungsgesetz" has been validated by the legislators. It precisely sets out how physicians and nursing staff have to deal with a written declaration of a patient's will. This new law focuses in a special way on advance directives, describes the precise rules for the authors of an advance directive and shows both its sphere of action and its limitations. This article aims to give an overview on the legal scope of advance directives, and to illustrate potential limitations and conflicts. Furthermore, it shows the commitments and rights of the medical team against the background of an existing advance directive.

Liver injury following blunt abdominal trauma: a new mechanism-driven classification.

PURPOSES: The current classifications for blunt liver trauma focus only on the extent of liver injury. However, these scores are independent from the localization of liver injury and mechanism of trauma. METHODS: The type of liver injury after blunt abdominal trauma was newly classified as type A when it was along the falciform ligament with involvement of segments IVa/b, III, or II, and type B when there was involvement of segments V-VIII. With the use of a prospectively established database, the clinical, perioperative, and outcome data were analyzed regarding the trauma mechanism, as well as the radiological and intraoperative findings. RESULTS: In 64 patients, the type of liver injury following blunt abdominal trauma was clearly linked with the mechanism of trauma: type A injuries (n = 28) were associated with a frontal trauma, whereas type B injuries (n = 36) were found after complex trauma mechanisms. The demographic data, mortality, ICU stay, and hospital stay showed no significant differences between the two groups. Interestingly, all patients with type A ruptures required immediate surgical intervention, whereas six patients (16.7 %) with type B ruptures could be managed conservatively. CONCLUSIONS: This new classification for blunt traumatic hepatic injury is based on the localization of parenchymal disruption and correlates with the mechanism of trauma. The type of liver injury correlated with the necessity for surgical therapy.

[Benchmarking surgical resources--a work sampling analysis at a German university hospital]. / Ärztliche Ressourcennutzung in der Chirurgie auf dem Prüfstand--eine Worksampling-Analyse an einer deutschen Universitätsklinik.

INTRODUCTION: Work densification caused by lack of young surgeons with increased clinical documentation keeps surgeons busy. It is proven by many studies that surgeons work significantly longer hours per week and deal with a larger amount of medical and non-medical documentation than staff members in conservative disciplines. The aim of the study was to investigate surgeons work distribution in a surgical university department and to evaluate by means of a work sampling analysis whether it can be standardised and slimmed down by systematic use of IT-supported, process-managed work-flow. In addition the data obtained are compared wuith those from other studies on similar topics. METHODS: Based on the results of an independent pilot observational study, 21 surgeons (14 residents, 7 staff surgeons) had to document over a 10-day period in a self-observation once in an hour their actual activity in a two dimensional matrix concerning medical activity (13 items) and patient contact (5 items). After the study, each physician had to estimate his/her own work distribution. Real percentages of the self-observation study were compared to the physicians' estimates of work distribution. IT-supported clinical pathways have been implemented since 2004 in our department. RESULTS: Over a ten-day evaluation period (1830 observation points), surgeons spent 30.2% of their activity in the operating theatre or on direct patient care. During 13.9% they were in meetings and they spent 10.8% of their time on documentation. Time needed for studying medical records (9.2%) and ward rounds (9.0%) ranged in a similar way. There was a significant accordance of estimated and real work distribution concerning the 5 most frequent daily activities. In only 14% there was no direct patient relationship. CONCLUSION: Application of work sampling analysis in surgery is a valid procedure for the evaluation of work flows in the course of personal observations. Surgeons working time in a hospital is limited. To achieve a maximum of direct patient care, clinical documentation has to be optimised by process automatisation within the context of IT-supported clinical pathways. Surgeons are able to estimate very exactly the distribution of their daily activities so that data of working time estimations is valuable.

Hepatic arterial infusion with tumor necrosis factor-α induces early hepatic hyperperfusion.

BACKGROUND: Hepatic arterial infusion (HAI) has been developed for high-dose regional chemotherapy of unresectable liver metastases or primary liver malignancies. While it is well known that high concentrations of tumor necrosis factor (TNF)-α damage tumor blood perfusion, there is no information on whether autochthonous liver perfusion is affected by HAI with TNF-α. Therefore, we investigated the effects of HAI with TNF-α on hepatic macro- and microvascular perfusion. METHODS: Swabian Hall pigs were randomized into three groups. HAI was performed with either 20 or 40 µg/kg body weight TNF-α (n = 6 each group). Saline-treated animals served as controls (n = 6). Analyses during a 2-hour post-HAI observation period included systemic hemodynamics, portal venous and hepatic arterial blood flow, portal venous pressure, and the blood flow in the hepatic microcirculation. RESULTS: HAI with TNF-α caused a slight decrease of mean arterial blood pressure (p < 0.001), which was compensated by a moderate increase of heart rate (p < 0.001). No further systemic side effects of TNF-α were observed. HAI with TNF-α further caused a slight but not significant decrease of portal venous blood flow (p = 0.737) in both experimental groups, paralleled by an increase of hepatic arterial blood flow (p = 0.023, 20 µg/kg; p = 0.034, 40 µg/kg) resulting in an overall hepatic hyperperfusion. The hepatic hyperperfusion after HAI with 20 µg/kg TNF-α was more pronounced and associated with a 40% decrease of the blood flow in the hepatic microcirculation (p = 0.009). HAI with 40 µg/kg TNF-α was only associated with a temporary and moderate total hepatic hyperperfusion and did not affect the blood flow in the hepatic microcirculation. CONCLUSION: HAI with TNF-α causes a decrease of portal venous flow; however, this is overcompensated by an increased hepatic arterial blood flow, resulting in a total hepatic hyperperfusion. Moderate total hepatic hyperperfusion does not affect the blood flow in the hepatic microcirculation, while a persistent and more pronounced hyperperfusion may cause hepatic microcirculatory disturbances.

A comparative evaluation of ablations produced by high-frequency coagulation-, argon plasma coagulation-, and cryotherapy devices in porcine liver.

INTRODUCTION: Hepatic resection is the only curative treatment option for primary or metastatic malignancies of the liver. Although R1 resections can also lead to prolonged survival, the main surgical goal is complete tumor resection (R0). To achieve this, additional treatment of the resection margin with ablation devices is discussed. Using a porcine in vivo model, we therefore analyzed the effect of different ablation devices on depth and completeness of hepatic parenchymal cell destruction. METHODS: Swabian-Hall strain pigs underwent ablation on the surface of the right, middle, or left liver lobe using seven different types of high-frequency (HF)-, cryotherapy (Cryo)-, or argon plasma coagulation (APC) devices. Penetration depth and volume were analyzed from histological sections. Severity of parenchymal cell destruction was assessed by a histomorphological score. RESULTS: The greatest penetration depth was achieved with Cryo (10.4 ± 1.7 mm), whereas HF and APC exhibited a smaller penetration depth. However, HF and APC compared to Cryo achieved complete destruction of the intralobular architecture and hepatocellular morphology depending on the application time and the adjusted power. CONCLUSION: HF, APC, and Cryo applied to the liver surface induce different parenchymal penetration depth and cell destruction. HF and APC are considered to be standard surgical instruments and therefore recommended as standard treatment, whereas Cryo may be used only if particularly deep penetration is required.

Graft-versus-host disease or toxic epidermal necrolysis: diagnostic dilemma after liver transplantation.

Graft-versus-host disease (GvHD) and toxic epidermal necrolysis (TEN) are rare and severe complications after liver transplantation. While mild acute GvHD is quite different from TEN and easy to distinguish, severe acute GvHD and TEN can be hard to differentiate because of similar clinical symptoms. We herein report a case with rapid progression of critical illness, after liver transplantation, caused by GvHD or TEN, although between those, diagnosis was not possible during the clinical course. Although, based on the timing/progression of the symptoms and the chimerism of >40%, the case seemed much more clinically consistent with GVHD, the combination of clinical symptoms together with skin rashes and the histologic appearance of skin lesions indicated diagnosis of a Stevens-Johnson syndrome/TEN overlap. The true diagnostic dilemma in such cases is discussed in detail, as these cases emphasize the need for more advanced diagnostic techniques.

[Reduced time-frame for ward rounds and patient satisfaction]. / Arbeitszeitkonformes Visitenmodell und Patientenzufriedenheit.

INTRODUCTION: The introduction in 2006 of the European legislation restricting physicians work-ing hours has had a dramatic impact on working conditions. This restriction called for a marked improvement in hospital workflow, leading to a reduction of time spent on ward rounds. We conducted an opinion survey assessing patient satisfaction in the area of markedly reduced ward rounds. MATERIALS AND METHODS: By January 2009, the time-frame allowed for morning ward rounds had been reduced by 33 % from 45 to 30 min. At the same time, the attendance of the senior staff surgeon was declared mandatory on each ward round. We conducted a prospective study, assessing patient satisfaction over a period of 3 months. RESULTS: 86 patients with an average age of 56.7 years were repeatedly questioned by a single investigator. Average length of hospital stay was 7.2 days. Patients expected ward rounds to average 5.3 min, which was significantly higher than actually observed. However, an overall patient satisfaction of above 80 % could be measured. CONCLUSION: In spite of the reduced time spent on ward rounds, a high level of overall patient satisfaction can be obtained due to the regular attendance of a senior staff surgeon. Process management is furthermore endorsed by the routine -application of clinical pathways in patient management.

Octreotide prophylaxis is not beneficial for biochemical activity and clinical severity of postoperative pancreatic fistula after pancreatic surgery.

BACKGROUND: Prospective randomized trials indicate that prophylactic octreotide treatment does not decrease the incidence of postoperative pancreatic fistula (POPF). The aim of this study was to analyze if octreotide prophylaxis could decrease the severity grade of POPFs after pancreatic surgery. METHOD: Seventy-eight of 684 patients undergoing pancreatic resection with POPF were included in the study. Prophylactic octreotide treatment was started immediately after surgery and was performed in 22 patients, whereas 56 patients had no octreotide treatment and served as controls. Lipase activity was measured in the abdominal drainage on postoperative days (POD) 3, 5 and 7. Primary endpoints of the study were clinical severity of the POPF and lipase activity in the drainage. RESULTS: There was no significant difference concerning length of postoperative hospital stay. Lipase activity in the abdominal drainage was not influenced by octreotide prophylaxis at POD 5 or 7 compared to POD 3. Multivariate analysis showed that the risk to develop a type B or C fistula in the octreotide group was independent of the kind of operation and the consistency of the pancreas (RR = 3.4; CI = 1.0-11.7; p = 0.050 and RR = 6.3; CI = 1.4-29.6; p = 0.019). CONCLUSION: Octreotide prophylaxis after pancreatic surgery has no beneficial effect on clinical severity of POPF.

[Increasing efficiency and patient satisfaction by structured clinical processes in presurgical visits]. / Steigerung von Effizienz und Patientenzufriedenheit durch strukturierte Prozesse am Beispiel der Prämedikationsambulanz.

BACKGROUND: In clinical routine the process of presurgical visit and signed informed consent is imperfectly realized in surgical patients. MATERIAL AND METHODS: A total of 450 consecutive patients were interviewed after a presurgical visit for informed consent using a questionnaire. The aim of the study was to investigate the amount of knowledge gained by informed consent. Patient satisfaction with medical treatment and logistic workflow was correlated with real waiting times and process times. RESULTS: Mean information duration was 36.1±0.8 min. In patients with no appointed time, waiting times and overall stay was shorter. Patient's satisfaction with medical treatment and time process was significantly higher in the elderly. Longer conversation with the surgeon was associated with a higher assessment of surgeons' medical experience irrespective of his specialist's state. Real waiting times did not affect patient's satisfaction. CONCLUSION: A walk-in clinic for presurgical visit and signed informed consent can improve patient satisfaction. It allows an excellent patients information in an appropriate time-frame. Clinical pathways can improve patient satisfaction and information concerning the lining up operation and disease pattern.

Tumour growth following portal branch ligation in an experimental model of liver metastases.

BACKGROUND: Portal branch ligation (PBL) is being used increasingly before hepatectomy for colorectal metastases. This study evaluated the effect of PBL on angiogenesis, growth factor expression and tumour growth in a mouse model of hepatic colorectal metastases. METHODS: CT26.WT cells were implanted into the left liver lobe of BALB/c mice. Animals underwent PBL of the left liver lobe or sham treatment. Angiogenesis, microcirculation, growth factor expression, cell proliferation and tumour growth were studied over 14 and 21 days by intravital multifluorescence microscopy, laser Doppler flowmetry, immunohistochemistry and western blotting. RESULTS: Left hilar blood flow and tumour microcirculation were significantly diminished during the first 7 days after PBL. This resulted in tumour volume being 20 per cent less than in sham controls by day 14. Subsequently, PBL-treated animals demonstrated recovery of left hilar blood flow and increased expression of hepatocyte growth factor and transforming growth factor alpha, associated with increased cell proliferation and acceleration of growth by day 21. CONCLUSION: PBL initially reduced vascular perfusion and tumour growth, but this was followed by increased growth factor expression and cell proliferation. This resulted in delayed acceleration of tumour growth, which might explain the stimulated tumour growth observed occasionally after PBL.

Laser Doppler flowmetry of hepatic microcirculation during Pringle's maneuver: determination of spatial and temporal liver tissue perfusion heterogeneity.

BACKGROUND: Laser Doppler flowmetry (LDF) is frequently used for non-invasive microvascular perfusion measurements. The aim of the present study was to analyze liver blood flow heterogeneity in detail using LDF devices under normal and low-flow conditions. MATERIALS AND METHODS: In 5 anesthetized and laparotomized Suabian-Hall strain pigs, systemic hemodynamics and hepatic arterial/portal venous blood flow were constantly recorded. Hepatic microcirculation was assessed by 2 different LDF devices, analyzing microvascular flow and velocity before, during and after inducing a Pringle's maneuver for hepatic inflow occlusion. Offline data analysis comprised differentiation between the two LDF devices used as well as calculation of temporal and spatial heterogeneity of liver perfusion. RESULTS: Pringle's maneuver induced complete inflow occlusion, confirmed by hepatic arterial/portal venous blood flow measurement. Laser Doppler signals showed a significant decrease during Pringle's maneuver. Spatial heterogeneity of flow and velocity increased more than temporal heterogeneity during Pringle's maneuver. CONCLUSION: Both LDF devices proved suitable for assessing hepatic microvascular perfusion during normal perfusion and low-flow conditions. Reduced microvascular perfusion induces a significant increase in temporal and spatial perfusion heterogeneity. In particular, the pronounced spatial heterogeneity requires measurements at different places when assessing hepatic microcirculation by LDF during impaired perfusion conditions.