Preoperative levosimendan infusion in combined aortic valve and coronary bypass surgery.

BACKGROUND: Cardiopulmonary bypass may have detrimental effects on intestinal function and decrease the concentrations of the active, long-acting metabolites of levosimendan, an inodilator used to improve cardiac function. The aim of this study was to evaluate the haemodynamic effects of preoperative levosimendan in patients undergoing high-risk cardiac surgery. METHODS: Twenty-four patients were randomized to receive levosimendan (12 µg bolus followed by an infusion of 0.2 µg kg(-1) min(-1)) or a placebo 24 h before surgery. The inclusion criteria were left ventricular ejection fraction (LVEF) <50% or LV hypertrophy indicated by a wall thickness of >12 mm. Haemodynamics were recorded every hour for 24 h (pulmonary artery catheter) and daily until postoperative day 4 (whole-body impedance cardiography). Doppler echocardiography with tissue Doppler imaging was used to assess systolic and diastolic cardiac function. RESULTS: The cardiac index (CI) and stroke volume index (SI) were higher in the levosimendan group (LG) for the 4 day postoperative period (P<0.05); on the fourth postoperative day, the CI was 3.0 litre m(-2) min(-1) in the LG compared with 2.4 litre m(-2) min(-1) in the control group (CG) and the SI was 30 vs 25 ml m(-2), respectively. The LVEF measured at baseline and on the fourth postoperative morning decreased in the CG, but was maintained in the LG. CONCLUSIONS: Levosimendan improved haemodynamics compared with a placebo in patients undergoing high-risk cardiac surgery. The concentrations of levosimendan's metabolites were higher compared with earlier studies using perioperative dosing.

Hyper osmolality does not modulate natriuretic peptide concentration in patients after coronary artery surgery.

BACKGROUND: The heart secretes natriuretic peptides (NPs) in response to myocardial stretch. Measuring NP concentrations is a helpful tool in guiding treatment. It has been suggested that sodium ion and hyperosmolality could affect NP excretion. If this is true, peri-operative NP measurements could be inconsistent when hypertonic solutions are used. With different osmolalities but equal volumes of hydroxyethyl starch (HES)--and hypertonic saline (HS)--infusions, this double-blinded study tested the hypothesis that osmolality modulates the excretion of NPs. METHODS: Fifty coronary surgery patients were randomized to receive within 30 min 4 ml/kg either HS or HES post-operatively. Samples for analysis of atrial NP (ANP), brain NP (BNP), plasma and urine sodium and osmolality and urine oxygen tension were obtained before and 60 min after starting the infusions and on the first post-operative morning. The haemodynamic parameters were measured at the same time points. RESULTS: Plasma osmolality and sodium increased only in the HS group. Changes in plasma BNP and ANP levels did not differ between the groups (P=0.212 and 0.356). There were no correlations between NP levels and osmolality or sodium at any time point. In the HS group, urine volume was higher (3295 vs. 2644 ml; P<0.05) and the need for furosemide treatment was less (0.4 vs. 3.8 mg; P<0.01) than in the HES group. CONCLUSIONS: The absence of effects of plasma sodium content or hyperosmolality on NP release validates the value of NPs as a biomarker in peri-operative patients.

Effects of levosimendan on indocyanine green plasma disappearance rate and the gastric mucosal-arterial pCO2 gradient in abdominal aortic aneurysm surgery.

BACKGROUND: Levosimendan has a dual mechanism of action: it improves myocardial contractility and causes vasodilatation without increasing myocardial oxygen demand. In a laboratory setting, it selectively increases gastric mucosal oxygenation in particular and splanchnic perfusion in general. The aim of our study was to describe the effects of levosimendan on systemic and splanchnic circulation during and after abdominal aortic surgery. METHODS: Twenty abdominal aortic aneurysm surgery patients were randomized to receive either levosimendan (n=10) or placebo (n=10) in a double-blinded manner. Both the mode of anaesthesia and the surgical procedures were performed according to the local guidelines. Automatic gas tonometry was used to measure the gastric mucosal partial pressure of carbon dioxide. Systemic indocyanine green clearance plasma disappearance rate (ICG-PDR) was used to estimate the total splanchnic blood flow. RESULTS: The immediate post-operative recovery was uneventful in the two groups with a comparable, overnight length of stay in the intensive care unit. Cumulative doses of additional vasoactive drugs were comparable between the groups, with a tendency towards a higher cumulative dose of noradrenaline in the levosimendan group. After aortic clamping, the cardiac index was higher [4(3.8-4.7) l/min/m(2) vs. 2.6(2.3-3.6) l/min/m(2); P<0.05] and the gastric mucosal-arterial pCO(2) gradient was lower in levosimendan-treated patients [0.9(0.6-1.2) kPa vs. 1.7(1.2-2.1) kPa; (P<0.05)]. However, the total splanchnic blood flow, estimated by ICG-PDR, was comparable [29(21-29)% vs. 20(19-25)%; NS]. Organ dysfunction scores (sequential organ dysfunction assessment) were similar between the groups on the fifth post-operative day. CONCLUSION: Levosimendan favours gastric perfusion but appears not to have a major effect on total splanchnic perfusion in patients undergoing an elective aortic aneurysm operation.

Etoricoxib pre-medication for post-operative pain after laparoscopic cholecystectomy.

BACKGROUND: Etoricoxib alleviates and prevents acute pain. The hypothesis of our study was that the pre-operative use of etoricoxib would reduce the post-operative need for additional pain treatment. METHODS: In this double-blind, randomized and active placebo-controlled study, 75 patients were pre-medicated 1.5 h before elective laparoscopic cholecystectomy with 120 mg of etoricoxib (E120 group), the same dose of etoricoxib combined with 1 g of paracetamol (E + P group) or placebo (Pla group). To alleviate post-operative pain, a patient-controlled analgesia (PCA) device was programmed to deliver 50 microg of fentanyl intravenously (lockout time, 5 min). The pain intensity and nausea were assessed using a visual analogue scale (VAS). The number of patients with post-operative nausea and vomiting was recorded. Blood loss was compared between the groups. Because the operations are almost blood-less, the operation time was also recorded to compare the possible effect on bleeding time. RESULTS: Pre-medication with etoricoxib or etoricoxib plus paracetamol had a statistically significant fentanyl-sparing effect 2-20 h post-operatively compared with placebo (P = 0.001). No significant differences were demonstrated in fentanyl-sparing effect between the E120 and E + P groups. No significant differences in pain intensity were found between the three study groups. No significant differences were observed between the groups with regard to nausea, blood loss, duration of anaesthesia or duration of surgery. CONCLUSION: Etoricoxib is suitable for pre-medication before laparoscopic cholecystectomy as it reduces the need for post-operative opioids. Opioid-related side-effects, however, were not reduced in the present study, despite the observed opioid-sparing effect of etoricoxib and combined etoricoxib and paracetamol.

Effects of cigarette smoking on serum fluoride concentrations and renal function integrity after 1 MAC-h sevoflurane anaesthesia.

BACKGROUND: Tobacco smoke contains various chemicals which may affect drug metabolism. Sevoflurane is metabolized to inorganic fluoride, and elevated serum fluoride concentrations (S-F(-)) may cause deterioration of renal function. Whether smokers develop high S-F(-) and associated disturbances in renal function is not known. METHODS: We investigated sevoflurane metabolism in 25 non-smoking and 25 smoking (> 10 cigarettes/day) generally healthy women, aged 19-68 years, undergoing gynaecological elective surgery under one minimum alveolar concentration-hour (1 MAC-h) standardized sevoflurane anaesthesia. S-F(-) was measured for 24 h. Glomerular and tubular function was assessed by measuring serum and urine tumour-associated trypsin inhibitor (TATI), beta(2)-microglobulin and serum creatinine for 48 h after sevoflurane inhalation. RESULTS: There were no differences between the two study groups with regard to S-F(-). It increased significantly in both groups: in non-smokers, from a baseline between 1.0 and 11 micromol/l (median, 1.6 micromol/l) to a maximum between 8.2 and 40 micromol/l (26 micromol/l) (P < 0.001) and, in smokers, from a baseline between 0.5 and 5.2 micromol/l (1.7 micromol/l) to a maximum between 19 and 71 micromol/l (25 micromol/l) (P < 0.001). In both groups, S-F(-) remained elevated for the entire sampling period (P < 0.001). In all five women (one non-smoker and four smokers) with a maximum S-F(-) of 40 micromol/l or higher and an area under the serum fluoride concentration-time curve (AUC(F0-24)) of 500 micromol/h/l or higher, serum TATI increased above the pathological concentration of 3.0 nmol/l, whereas only six of the 45 patients with S-F(-) below 40 micromol/l had serum TATI above 3.0 nmol/l (P < 0.001). Beta(2)-Microglobulin increased significantly (> 1 mg/l) in two patients with high S-F(-) relative to two of the 45 patients with S-F(-) below 40 micromol/l (P= 0.005). None of the patients developed clinically detectable renal dysfunction. CONCLUSION: Smoking did not affect S-F(-) after sevoflurane anaesthesia. Glomerular dysfunction, seen as increased serum TATI, was noted in five women with S-F(-) above 40 micromol/l. Our results suggest that the renal toxic threshold of S-F(-) seems to be lower than the earlier reported value of 50 micromol/l.

Lack of analgesic effect of parecoxib following laparoscopic cholecystectomy.

BACKGROUND: The cyclo-oxygenase-2 inhibitor, parecoxib, can be administered parenterally. The recommended dose for post-operative use is 40 mg twice daily, which may not be the appropriate dose for the treatment of visceral pain. We studied the effect of a single dose of parecoxib of either 40 or 80 mg in laparoscopic cholecystectomy, and its effect on opioid-induced side-effects. METHODS: Seventy-three patients scheduled for elective laparoscopic cholecystectomy were enrolled in this prospective, randomized, double-blind study. Patients were randomized into three groups: a placebo-treated control group, a 40-mg parecoxib-treated group (P40) and an 80-mg parecoxib-treated group (P80). We recorded the cumulative fentanyl consumption during the first 20 h post-operatively by patient-controlled analgesia equipment, the pain scores during rest, coughing and mobilization (visual analogue scale, 0-10), the worst pain during the first 2 h post-operatively and in the following 18 h, and the side-effects by questionnaire. RESULTS: No significant differences in fentanyl consumption between the three groups could be detected. The worst pain experienced between 2 and 20 h post-operatively on the ward was significantly lower in the P80 group than in the control group. CONCLUSION: The recommended dose of parecoxib, 40 mg, is not effective for the treatment of pain during the early post-operative period after laparoscopic cholecystectomy. Doubling the dose to 80 mg seems to improve the results.

Endovascular vs open AAA repair: similar effects on renal proximal tubular function.

AIM: To compare the effect of open and endovascular repair on renal function. MATERIALS AND METHODS: In a prospective, non-randomized study twenty-four abdominal aortic aneurysms (AAA) treatable with either method were repaired, 15 using endovascular device (ENDO group) and nine with open surgery with infrarenal aortic cross-clamping (OPEN group). All the patients had standardised general anaesthesia, intravascular fluid therapy and monitoring. Renal function tests and cardiovascular measurements were performed at predetermined intervals. RESULTS: N-acetyl-beta-D-glucosaminidase indexed to urinary creatinine (U-NAG/crea), a sensitive marker of renal proximal tubular damage, increased similarly in both groups at the end of surgery (two-way ANOVA, p < 0.05). No patient developed clinical renal impairment, on the contrary, creatinine clearance was increased, serum cystatin C (a sensitive marker of renal glomerular filtration) and serum creatinine concentration decreased at 24 hours postoperatively (Wilcoxon paired test, p < 0.05). Intraoperative blood loss and the amount of administered crystalloids were higher in the OPEN than in the ENDO group (Mann-Whitney U-test, p < 0.05). The cardiovascular measurements were comparable between the groups. The mean (SD) amount of radio-contrast media given was 3.1 (1.1) ml/kg in the ENDO group. CONCLUSIONS: Our results indicate that endovascular AAA repair does not protect renal proximal tubular function. A temporary renal tubular dysfunction was found both in open and in endovascular AAA repair which did not lead to permanent changes in renal function.

Fluoride metabolism in smokers and non-smokers following enflurane anaesthesia.

BACKGROUND: Inorganic fluoride is released by the metabolism of enflurane and the increased serum fluoride concentrations may impair renal function. Tobacco smoke consists of numerous reactive compounds that can either induce or inhibit drug metabolism. Studies on the interaction of smoking with anaesthetic drug metabolism and possible toxicity are warranted. METHODS: Sixteen non-smoking and 17 smoking (>10 cigarettes day(-1)) generally healthy women undergoing elective gynaecological surgery were given 1 MAC (minimum alveolar concentration)-hour standardized anaesthesia with enflurane in oxygen-air mixture. The serum inorganic fluoride and renal function markers beta(2)-microglobulin, tumour-associated trypsin inhibitor (TATI) and serum creatinine were measured for 48 h. RESULTS: The greatest inorganic fluoride concentration was between 8.4 and 21.0 (mean 13.8 (SD 3.4)) micromol litre(-1) in the non-smokers and between 8.6 and 38.0 (18.7 (7.0)) micromol litre(-1) in the smokers; the mean difference was 4.9 micromol litre(-1) (95% confidence interval (CI) 1.0-8.8, P<0.05). Serum beta(2)-microglobulin, TATI and creatinine were not increased. Serum inorganic fluoride concentrations were significantly greater in the smokers compared with the non- smokers 1, 2, 3 and 6 h after 1 MAC-hour inhalation with enflurane (P<0.05). Inorganic fluoride concentrations were still increased 24 h after anaesthesia in both groups. Urine beta(2)-microglobulin and TATI creatinine ratio remained at low values during the whole 48-h period in both groups. CONCLUSIONS: Regular smoking is associated with an increase in serum inorganic fluoride concentration after anaesthesia with enflurane, but there are no signs of renal damage.

Experience with albumin dialysis in five patients with severe overdoses of paracetamol.

Five patients in whom the serum paracetamol levels or the amount of ingested paracetamol was high enough to cause severe liver injury were treated with N-acetyl-cysteine (NAC) and a molecular absorbant recirculating system (MARS). MARS treatment was started as early as possible in order to prevent or retard the development of hepatocyte necrosis. Four of our five patients survived without liver transplantation, and one died due to brain oedema. The early commencement with NAC and MARS treatments in paracetamol intoxication might give enough time for the liver to regenerate and thus avoid liver transplantation.

Sentinel node mapping affects intraoperative pulse oximetric recordings during breast cancer surgery.

BACKGROUND: In invasive breast cancer lymphatic mapping with patent blue vital dye (PBV) is used intraoperatively to identify the sentinel lymph nodes: the first axillary node draining the mammary lymphatic basin and first involved by the metastatic growth in breast cancer. Patent blue vital dye spreads to tissues giving a bluish tinge to patients. We have noted the possibility that intraoperative peripheral pulse oximetric (SpO2) values are artificially low when intradermal PBV is used. METHODS: Twenty patients with normal pulmonary function undergoing breast cancer surgery in standardized anesthesia either did or did not receive intradermal PBV sentinel node marking. The radial artery was cannulated for blood-gas-analysis; arterial oxygen tension (PaO2); and arterial oxygen saturation (SaO2). Peripheral oxygen saturation was measured using the light absorption technique. Red and infrared light (660 and 900 nm), used by pulseoxymetry, is partially absorbed when passing through the tissue. The amount of light absorbed is sensed and saturation calculated. The color of the skin was evaluated. RESULTS: Peripheral oxygen saturation decreased only immediately after the injection of PBV, and remained at a significantly lower level (P<0.001) throughout the operation and up to 90 min postoperatively. Arterial oxygen tension and SaO2 values did not decrease after intradermal PBV. Patent blue vital dye made patients' skin more bluish (P<0.001). No changes in SpO2, PaO2 and SaO2 were found in control patients. CONCLUSION: The spectrum of PBV has a peak absorption at 640 nm, thus making the SpO2 values incorrect. Peripheral oxygen saturation values are falsely low and true arterial oxygenation is not impaired when PBV is used during sentinel node mapping.

The effect of ketorolac and sevoflurane anesthesia on renal glomerular and tubular function.

UNLABELLED: We assessed the renal effects of the combination of ketorolac and sevoflurane anesthesia by using sensitive and specific markers of renal proximal and distal tubular and glomerular function. Thirty women (ASA physical status I and II) undergoing breast surgery received either ketorolac 30 mg IM or saline at premedication, at the end, and 6 h after anesthesia maintained with sevoflurane. Peak levels of serum fluoride at 2 h after the end of anesthesia were 30.1 micromol/L (21.0-50.0 micromol/L) in the Ketorolac group and 33.3 micromol/L (13.0-38.0 micromol/L) in the Control group (mean and range, not significant). Urine alpha1-microglobulin indexed to urine creatinine was increased from 2 h after the start of anesthesia until the first postoperative day in the Ketorolac group (peak level, 0.8 +/- 0.4 mg/mmol; upper limit of normal, 0.7 mg/mmol) but did not change in the Control group. Urine glutathione-S-transferase (GST)-alpha indexed to urine creatinine (GST-alpha/creatinine) and GST-pi/creatinine were increased 2 h after anesthesia and returned to baseline values thereafter in both groups. There were no changes in serum cystatin C and urine kallikrein or urine output per hour between groups. The perioperative administration of ketorolac to healthy, well hydrated patients anesthetized with sevoflurane did not produce renal glomerular or tubular dysfunction. IMPLICATIONS: Ketorolac 90 mg IM, given in divided doses over approximately 10 h to patients anesthetized with sevoflurane with a fresh gas flow rate of 4-6 L/min, did not result in clinically significant changes in renal glomerular or tubular function.

A test for cleaning and disinfection processes in a washer-disinfector.

Disinfection processes such as heat, aldehydes or alcohols kill vegetative microorganisms but do not necessarily remove other organic contamination. Organic residues impair the result of low-temperature sterilisation processes. Heat-stable organic residues may give rise to clinical symptoms in the patient. Standards are available in Britain and in Sweden for the examination of cleaning processes in washer-disinfectors. The test substances are artificial soil or blood. These standards are based on visual inspection of instruments or equipment. They cannot be used for examination of tubular instruments, nor can they be quantified. For validation of cleaning procedures a simple quantifiable method, which can be performed in an infection control laboratory is needed. We have used suspensions in horse blood of Enterococcus faecalis bacteria and Bacillus subtilis spores to test disinfection and cleaning in a washer-disinfector. Instruments used for laparoscopic surgery were contaminated with a blood bacteria suspension containing 10(7) organisms/ml and then dried and processed in a washer-disinfector using a regular process. Remaining microbial contamination was cultured quantitatively. Nineteen objects were investigated in 10 experiments each. Cleaning, measured as log reduction >5-6 of B. subtilis, was achieved on surfaces that were adequately in contact with the water flow in the machine. Disinfection (and cleaning) measured as log reduction >5-6 of E. faecalis was successful at all points examined. The test method is simple and quantifiable, and can be used to evaluate and to improve cleaning and disinfection processes.

Modifying the cellular transport of DNA-based vaccines alters the immune response to hantavirus nucleocapsid protein.

Puumala virus is a member of the hantavirus genus (family Bunyaviridae) and is one of the causative agents of hemorrhagic fever with renal syndrome (HFRS) in Europe. A genetic vaccination approach was conducted to investigate if the immune response could be modulated using different cellular secretion and/or localisation signals, and the immune responses were analysed in BALB/c mice and in a bank vole infectious model. Rodents vaccinated with DNA constructs encoding the antigen fused to an amino-terminal secretion signal raised significantly higher antibody levels when compared to using constructs lacking secretion signals. Furthermore, the ratios of the IgG subclasses (IgG2a/IgG1) were raised by the use of cellular localisation signals, indicating a more pronounced Th1-type of immune response. The majority of the mice, or bank voles, immunised with DNA encoding a secreted form of the antigen showed a positive lymphoproliferative response and were protected against challenge with Puumala virus (strain Kazan-wt).

Cyclosporine induces myocardial connective tissue growth factor in spontaneously hypertensive rats on high-sodium diet.

BACKGROUND: The introduction of cyclosporine (CsA) has led to an improvement in the prognosis of solid organ transplantation. However, drug-induced hypertension and nephrotoxicity, associated with the development of atherosclerosis and coronary heart disease, still worsen the long-term outcome of CsA-treated patients. Whether the CsA-induced myocardial changes are associated with the induction of connective tissue growth factor (CTGF), a recently found polypeptide implicated in extracellular matrix synthesis, is not known. METHODS: Spontaneously hypertensive rats (8-9 weeks old) were treated with CsA (5 mg x kg(-1) x d(-1) subcutaneously) for 6 weeks. The influence of angiotensin-converting enzyme inhibition (enalapril 30 mg x kg(-1) x d(-1) orally) and angiotensin-1 receptor blockade (valsartan 3 and 30 mg x kg(-1) x d(-1) orally) on CsA toxicity was also investigated. Myocardial morphology was examined, and vascular lesions were scored. Localization and the quantitative expression of CTGF, as well as collagen I and collagen III, mRNA were evaluated by in situ hybridization and Northern blot. RESULTS: CsA-induced hypertension and nephrotoxicity were associated with myocardial infarcts and vasculopathy of the coronary arteries. CsA increased myocardial CTGF, collagen I, and collagen III mRNA expressions by 91%, 198%, and 151%, respectively. CTGF mRNA expression colocalized with the myocardial lesions. Blockade of the renin-angiotensin system prevented vascular damage and the CsA-induced CTGF, collagen I, and collagen III mRNA overexpressions in the heart. CONCLUSIONS: CsA increases CTGF, collagen I, and collagen III mRNA expressions in the heart. The induction of CTGF gene is mediated, at least in part, by angiotensin II.

Ketorolac is not nephrotoxic in connection with sevoflurane anesthesia in patients undergoing breast surgery.

UNLABELLED: Ketorolac, which may cause renal vasoconstriction by cyclooxygenase inhibition, is often administered to patients anesthetized with sevoflurane that is metabolized to inorganic fluoride (F(-)), another potential nephrotoxin. We assessed this possible interaction using urine N-acetyl-beta-D-glucosaminidase indexed to urinary creatinine (U-NAG/crea) as a marker of proximal tubular, beta2-microglobulin as a tubular, urine oxygen tension (P(u)O(2)) as a medullary, and erythropoietin as a marker of tubulointerstitial damage. Thirty women (ASA physical status I-II) undergoing breast surgery were included in our double-blinded study. They were allocated into two groups receiving either ketorolac 30 mg IM (Group K) or saline (Group C) at the time of premedication, at the end of, and 6 h after anesthesia maintained with sevoflurane. Urine output, U-NAG/crea, P(u)O(2,) serum creatinine, urea, and F(-) were assessed. Blood loss was larger in Group K (465 +/- 286 mL vs 240 +/- 149 mL, mean +/- SD, P < 0.05). The MAC-doses of sevoflurane were similar. U-NAG/crea increased during the first 2 h of anesthesia and serum F(-) peaked 2 h after the anesthesia without differences between the groups. There were no statistically significant changes in P(u)O(2), erythropoietin, beta2-microglobulin, serum creatinine, urea, or urine output during anesthesia or the recovery period in either group. Our results indicate that the kidneys are not affected by ketorolac administered in connection with sevoflurane anesthesia. IMPLICATIONS: The different kinetics of N-acetyl-beta-D-glucosaminidase indexed to urinary creatinine and serum inorganic fluoride during and after sevoflurane anesthesia suggest that the observed mild renal tubular function deterioration is not caused by inorganic fluoride. Administration of ketorolac IM is therefore considered safe in adequately hydrated healthy adult patients given sevoflurane anesthesia.

Are diabetic patients in danger at renal transplantation? An invasive perioperative study.

It is assumed that diabetic patients with uraemia have more complications at renal transplantation than those who are not diabetic. We compared the preoperative ECGs, and invasive perioperative haemodynamic and oxygenation parameters in 15 diabetic and 15 non-diabetic uraemic patients undergoing renal transplantation. The number of patients with increased QT dispersion in the ECG was higher in diabetic than in non-diabetic patients (P<0.05). Before anaesthesia, heart rate and mean arterial pressure were higher (P<0.05) in the diabetic than in the non-diabetic group. After preanaesthetic volume loading all patients showed a hyperdynamic circulation, which subsided during anaesthesia. However, stroke volume index remained unchanged. Four patients in the diabetic group and six in the non-diabetic group needed additional oxygen therapy after surgery. No cardiac dysrhythmias were noted. However, the increased QT dispersion in diabetic patients calls for an adequate perioperative ECG monitoring for dysrhythmias. The diabetic and non-diabetic uraemic patients performed equally well at renal transplantation. In conclusion, renal transplantation for diabetics is justified.

Cerebral blood flow and oxygenation in liver transplantation for acute or chronic hepatic disease without venovenous bypass.

The autoregulation of cerebral blood flow (CBF) is impaired in patients with end-stage liver disease and encephalopathy. These patients are vulnerable to sudden deterioration of cerebral perfusion and oxygenation during liver transplantation. We compared CBF and metabolism during liver transplantation without venovenous bypass and 24 hours postoperatively in 9 patients with acute liver failure (ALF) and 16 patients with chronic liver disease. A fiberoptic catheter was inserted cranially through the left internal jugular vein for determination of jugular venous oxygen saturation, cerebral oxygen extraction ratio (COER), lactate level, and neuron-specific enolase (NSE) level. Arterial concentrations of lactate were also measured. Flow velocity in the middle cerebral arteries was monitored bilaterally using transcranial Doppler sonography. Mean flow velocity and pulsatility index (PI) were regarded as indicators of intracranial pressure. Core body temperatures were recorded. Mild hyperventilation, perioperative hemofiltration, and N-acetylcysteine infusion were used according to our clinical practice. NSE level was greater in acute patients at the end of surgery (P <.05), but not 24 hours later. Lactate concentrations were greater in patients with ALF (P <.001) preoperatively and intraoperatively but were similar in both groups 24 hours postoperatively. There was no difference between arterial and jugular venous concentrations of lactate. Changes in blood flow velocity, PI, and COER were parallel and without statistical significance between the groups. The patients' core temperature did not correlate with CBF, NSE level, or clinical outcome. Caval clamping was well tolerated in both patient groups.

Beneficial effects of dietary magnesium and potassium on cardiac and renal morphologic features in cyclosporin A-induced damage in spontaneously hypertensive rats.

BACKGROUND: Cyclosporin A-induced hypertension is dependent on the level of dietary salt. We investigated whether dietary magnesium or potassium could protect against cyclosporin A-induced cardiac and renal damage in spontaneously hypertensive rats (SHRs) on high-sodium diet. METHODS: Eight-week-old SHRs were divided into 4 groups: (1) receiving a high-sodium diet, (2) receiving a high-sodium, high-potassium diet, (3) receiving a high-sodium, high-magnesium diet, and (4) receiving a high-sodium, high-potassium, high-magnesium diet. The effects of cyclosporin A in SHRs on a relatively low-sodium diet and in normotensive Wistar-Kyoto rats were also examined. Cardiac and renal morphologic condition was assessed, and tissue damage was scored by light microscopy after 6 weeks of cyclosporin A treatment. RESULTS: In SHRs on a high-sodium diet, cyclosporin A caused luminal narrowing of the coronary arteries, left ventricular scarring, and damage in the renal arterioli and glomeruli. Dietary magnesium supplementation alone and in combination with potassium protected against these changes, whereas potassium alone was less effective. Cyclosporin A treatment caused only minor histopathologic changes in SHRs receiving a low-sodium diet. Interestingly, the detrimental interaction between cyclosporin A and a high-sodium diet was also observed in normotensive Wistar-Kyoto rats. CONCLUSIONS: Dietary magnesium, especially in combination with potassium, protects against cyclosporin A-induced cardiac and renal damage.

Effect of intra-aortic magnesium on renal function during and after abdominal aortic surgery: a pilot study.

BACKGROUND: Infrarenal aortic cross-clamping causes renal vasoconstriction. Magnesium may protect against renal deterioration through its vasodilatory properties. METHODS: Thirty patients with normal preoperative renal function undergoing infrarenal aortic cross-clamping for elective aortic surgery received magnesium (4 mmol) or saline into the aorta immediately after aortic cross-clamping and again just before unclamping in a double-blind fashion. Pulmonary artery occlusion pressure was maintained 215 mmHg. Five patients with magnesium were excluded due to need for intravenous nitroglycerine because of myocardial ischaemia during the study. RESULTS: Postoperative creatinine clearance remained unchanged in both groups. Urinary N-acetyl-beta-D-glucosaminidase excretion increased before and decreased after aortic cross-clamping in both groups. The concentrations of glutathione peroxidase in serum were identical between the two groups. CONCLUSIONS: These data indicate that intra-aortic magnesium had no effect on renal function during or after aortic cross-clamping.