Standardization of Ischemic Hepatic Failure in Pigs as a Model for Bioartificial Liver Assessment

Purpose. A standard protocol of ischemic liver failure in pigs was examined to establish a system for assessing the efficacy of a bioartificial liver, based on clinical practice. Methods. The portal blood flow was extracorporeally bypassed into the cervical jugular vein, using a centrifugal blood pump. The portal vein and hepatic artery were then ligated. Results. The maintenance protocol was established as follows: (1) the concentration of the inhaled anesthetic was decreased by 0.2% when the systolic blood pressure was 100mmHg; (2) the volume of an infusion containing 5% glucose was increased to 10ml/kg per hour when central venous pressure was 5mmHg; (3) 20ml of 50% glucose was injected intravenously when the blood glucose was 50mg/dl; (4) 2000 units of heparin was injected intravenously when the activated clotting time was 150s; (5) sodium bicarbonate was given when the blood pH was 7.3; (6) tidal volume was increased by 1ml/kg when the pCO₂ was 80mmHg; (7) oxygen was increased by 25% when the pO₂ was 100mmHg. No vasopressors were used in the experiment. Conclusion. Our protocol reduced the operating time and minimized the risk of data deviation that can arise from variations in operating techniques and individual animal conditions. This experimental model is also easy to use as a bridge to transplantation.     

Elevation of the extracellular glutamate concentration in the hippocampus after total cerebral ischemia related to the deterioration of the recovery in EEG and evoked potentials in dogs

The concentrations of extracellular glutamate (Glu), aspartate (Asp) and glycine (Gly) were measured by microdialysis method in the cortex and hippocampus before, during and after 15min of total cerebral ischemia in dogs. The correlations between the concentrations of amino acids and the changes in EEG and evoked potentials (EP) after ischemia were evaluated. Total cerebral ischemia was achieved by occluding the ascending aorta and the caval veins. The concentrations of Glu in the hippocampus significantly increased from 1.73 ± 0.59 (mean ± SEM) nmol·ml^–1 at pre-ischemia to 5.46 ± 1.34 (P 0.05) during ischemia and 14.37 ± 3.70 (P 0.01) 0–15min after ischemia, and returned to the pre-ischemic level 30min after ischemia. The concentration of hippocampal Glu 0–15min after ischemia had significant negative correlations with the EEG-EP scores (0 = serious deterioration of electrical function and 6 = normal electrical function) 30min, 3hr and 5hr after ischemia (r = –0.69, P 0.05:r = –0.67, P 0.05:r = –0.70, P 0.05, respectively). The increase of the extracellular Glu concentration in the hippocampus immediately after ischemia may aggravate the neurological outcome after total cerebral ischemia.(Ono K, Iwatsuki N, Tajima T, et al.: Elevation of the extracellular glutamate concentration in the hippocampus after total cerebral ischemia related to the deterioration of the recovery in EEG and evoked potentials in dogs. J Anesth 7: 334–340, 1993)     

Sustained effects of plasma norepinephrine levels on femoral-radial pressure gradient after cardiopulmonary bypass

In order to determine the influence of the sympathetic nervous system upon the femoral-radial artery pressure gradient after cardiopulmonary bypass (CPB), we examined plasma norepinephrine levels in 34 adult male patients undergoing coronary artery bypass grafting. Cardiovascular parameters, including systolic arterial pressure, mean arterial pressure, cardiac index (CI), systemic vascular resistance index (SVRI), pulmonary artery pressure (PAP), hemoglobin (Hb) and peak dP/dt of radial and femoral artery pressures were measured after sternotomy, and immediately after the discontinuation of CPB and 90min after CPB. Plasma norepinephrine levels were measured after sternotomy, after aortic declamping and 90min after CPB.The patients were divided into two groups. Group A consisted of 17 patients whose femoral minus radial systolic pressure difference was 15mmHg or more at 90min after CPB, while Group B consisted of 17 patients with the difference less than 15mmHg. Group A patients had significantly longer time values in the duration of both CPB (Group A 175 ± 10min; Group B 115 ± 12min, P 0.001) and aortic cross clamping (Group A 116 ± 7min, Group B 71 ± 9min, P 0.001).Although there was no significant difference in Hb or PAP of 90min after CPB in Groups A and B, the following values, listed in the order of A to B, were obtained; CI, 2.79 ± 0.10 versus 3.46 ± 0.16l·min^–1·m^–2 (P 0.01); mean radial artery pressure (MRP), 58.7 ± 2.4 versus 65.1 ± 1.8mmHg (P 0.05); peak dP/dt of radial artery pressure, 568 ± 64 versus 1026 ± 61mmHg·sec^–1 (P 0.001); and plasma norepinephrine concentration, 1.81 ± 0.25 versus 0.98 ± 0.10ng·ml^–1 (P 0.01), which were statistically significant.The higher femoral-radial artery pressure gradient after CPB was observed in patients with both a longer CPB time and a higher plasma norepinephrine concentration. These results suggest that a marked constriction of peripheral arteries might have produced a damped transmission of the pressure pulse to the radial artery.(Nakayama R, Goto T, Kukita I, et al.: Sustained effects of plasma norepinephrine levels on femoral-radial pressure gradient after cardiopulmonary bypass. J Anesth 7: 8–15, 1993)     

Suppression of proliferative cholangitis in a rat model by local delivery of paclitaxel

Background. Proliferative cholangitis (PC) leads to biliary stricture, which is the main cause of hepatolithiasis, recurrent cholangitis, and biliary cirrhosis. The aim of this study was to determine whether local delivery of paclitaxel, which inhibits cell proliferation by overstabilization of microtubules, prevents PC in a rat model.Methods. PC was induced by introducing a fine nylon thread into the bile duct in a rat. Paclitaxel (100µl of 10, 100, and 1000µmol/l) or solvent vehicle was administered into the bile duct for 15min. One week after treatment, histopathologic examination and 5-bromodeoxyuridine (BrdU) labeling of the bile duct were performed.Results. In comparison with the control, the mean thickness of the bile duct was reduced by 29% in the 1000µmol/l paclitaxel-treated group (2.61 ± 0.31µm vs 3.67 ± 0.25µm, P 0.05). The luminal area increased (P 0.0001) and the grade of epithelial–glandular proliferation was decreased (P 0.01) as the dose of paclitaxel increased. Ductal fibrosis and inflammatory cell infiltration were similar in both groups. The BrdU labeling index was significantly lower in the paclitaxel-treated group (P 0.05).Conclusions. Local delivery of paclitaxel suppressed PC in a rat model by the inhibition of epithelial–glandular proliferation and may offer an effective therapeutic option for biliary stricture.     

Insulin-like growth factor-I increases p21 expression and attenuates cisplatin-induced acute renal injury in rats

Background Exogenous insulin-like growth factor-I (IGF-I) promotes recovery from ischemic renal injury, but its effect on cisplatin (CDDP)-induced nephrotoxicity and its mechanisms for the attenuation of renal injury are unknown.Methods We administered recombinant human IGF-I (rhIGF-I, 150µg/day, i.p.) once a day 24h prior to and after CDDP (5mg/kg, i.v.) injection in rats.Results The rhIGF-I treatment significantly decreased serum creatinine (0.92 ± 0.11 vs 1.50 ± 0.15mg/dl; P 0.05), the tubular damage score, and the ratio of apoptotic cells to tubular epithelial cells in the outer stripe of the outer medulla on day 5 (P 0.05). rhIGF-I significantly increased the numbers of p21-positive nuclei (5.15 ± 0.19 vs 3.45 ± 0.42/×400 high-power field (HPF); P 0.05) and proliferating cell nuclear antigen (PCNA)-positive nuclei (28.61 ± 1.89 vs 18.26 ± 2.14/×400 HPF; P 0.05), but decreased the number of cyclin D1-positive cells (3.3 ± 0.3 vs 6.3 ± 1.7/×400 HPF; P 0.05) on day 3. rhIGF-I did not alter 5-bromo-3-deoxyuridine (BrdU) incorporation.Conclusions Our findings suggested that rhIGF-I increased renal p21 and PCNA expression, but reduced cyclin D1 expression in CDDP-treated kidneys. Exogenous rhIGF-I may ameliorate renal damage, in part by stopping the cell cycle at G1/S phase.     

Induced hypotension for surgical repair of congenital dislocation of the hip in children

The surgical repair of congenital dislocation of the hip was performed under normotensive anaesthesia (23 children) and hypotensive anaesthesia (52 children). Hypotension was induced with infusion of hypotensive agents such as trimetaphan or nitroglycerin during inhalation or neurolept-anaeshesia under careful monitoring of blood pressure, haematocrit and electrocardiogram. Blood replacement was done to keep hematocrit value above 30%. Blood loss was significantly less in hypotensive group (2.53ml/kg/h) than that in normotensive group (4.53ml/kg/h). Twenty one percent of patients in hypotensive group required blood transfusion with the rate of 3.3ml/kg/h compared with 43% of cases in normotensive group with the rate of 4.4ml/kg/h. Depending upon anaesthesia technique blood loss was greater in neuroleptanaesthesia (5.5ml/kg/h) than inhalation (2.3ml/kg/h) or epidural (2.1ml/kg/h) anaesthesia. Urine output and laboratory data for liver and kidney functions were not different between normotensive and hypotensive group. The dose of hypotensive agents required to produce moderate hypotension for paediatric patients was much higher than that for adult. We consider that moderate hypotension is safe procedure if employed by well experienced anaesthetist with careful monitoring of blood pressure, Hct and ECG. Blood loss and requirement of blood replacement are significantly reduced with this technique.(Nam YT, Shin T, Yoshitake J: Induced hypotension for surgical repair of congenital dislocation of the hip in children. J Anesth 3: 58–64, 1989)     

The effects of calcitonin on bone resorption in hyperthyroidism: a placebo-controlled clinical study

The effects of intranasal calcitonin on bone metabolism were investigated in patients with hyperthyroidism. Urinary deoxypyridinoline (uDPD) levels were measured as a bone turnover marker and lumbar spine (L2) bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DEXA) in 7 patients who were given only antithyroid drug (group 1), in 10 patients who were given antithyroid drug plus intranasal calcitonin (group 2), and in 10 healthy subjects who were given placebo (group 3) at the beginning and at the end of the study. The study continued until the patients with hyperthyroidism became euthyroidic according to the laboratory values. This period was approximately 3 months in groups 1 and 2. At the beginning of the study, uDPD was 21.5 ± 2.6nM DPD/mM creatinine in group 1, 23.3 ± 3.6nM DPD/mM creatinine in group 2, and 4.3 ± 1.2nM DPD/mM creatinine in group 3. uDPD levels measured in groups 1 and 2 were significantly higher than those in group 3 (P 0.001). Area BMD Z scores of the patients in groups 1 and 2 were significantly lower than the healthy controls (P 0.01, for both). At the end of the study, uDPD was 11.5 ± 1.6nM DPD/mM creatinine in group 1, 5.3 ± 0.6nM DPD/mM creatinine in group 2, and 4.4 ± 1.3nM DPD/mM creatinine in group 3. The levels of uDPD obtained in group 1 were significantly higher than those obtained in groups 2 and 3 (P 0.05, for both). The difference between groups 2 and 3 was not significant. Area BMD Z scores measured at the end of the study were found to be increased in groups 1 and 2 compared to early values, but the values were slightly lower than the normal values. In comparison of early and late uDPD values, the decrease in late period was statistically significant in groups 1 (P 0.05) and 2 (P 0.001). We concluded that bone turnover is high in hyperthyroidism. The treatment of hyperthyroidism decreases the rate of bone turnover, but it is not sufficient to prevent the degradation of bone in hyperthyroidism. The addition of intranasal calcitonin to the treatment of hyperthyroidism prevents the degradation of bone.     

Hemodynamic responses during induction of anesthesia with halothane-nitrous oxide in children with or without atropine premedication

Forty three children ranged from 1yr. to 6yr. were randomly assigned to non-atropinized group (n = 20; A(–)) and atropinized group (0.015mg·kg^–1 i.m., n = 23; A(+)). Control hemodynamics were measured under 0.5% halothane and 67% nitrous oxide and 33% oxygen for three minutes, and then halothane was increased to 2.5% and maintained for 15min. In the A(–) group, stroke volume (SV) decreased to 64%, heart rate (HR) increased from 100/min to 111/min, and blood pressure (BP) decreased from 65mmHg to 62mmHg. Skin blood flow (SBF) concomitantly measured by a laser doppler flowmeter decreased to 48% and total peripheral resistance (TPR) increased to 128%. In the A(+) group, HR increased from 117/min to 132/min (P 0.05, vs. A(–) group), BP decreased from 67mmHg to 66mmHg. SV decreased to 71% (P 0.05, vs. A(–) group). Changes in SBF and TPR were 68% and 128% respectively. End-expired halothane concentration in the A(+) group increased slower than in the A(–) group but not significantly. The results indicate increased sympathetic tone would work as a compensating mechanism for decreased SV and CO. Atropine premedication attenuated cardiovascular depression by maintaing HR and possibly by delaying induction speed of anesthesia. In conclusion, halotane-nitrous oxide anesthesia decreased SV without a marked decrease in heart rate and blood pressure in children. This decrease in SV and BP was attenuated by atropine premedication.(Kawana S, Namiki A, Morita Y, et al.: Hemodynamic responses during induction on anesthesia with halothane-nitrous oxide in children with or without atropine premedication. J Anesth 6: 63–68, 1992)     

Positive inotropic and chronotropic effects of pancuronium and vecuronium in the canine blood-pefused papillary muscle and sinoatrial node preparations

The positive inotropic and chronotropic potencies of pancuronium (Pc) and vecuronium (Vc) were compared with developed tension of the isolated papillary muscle (DT) and sinoatrial rate of the sinoatrial node preparation (SAR). Both Pc and Vc caused dose-dependent positive inotropic and chronotropic effects. Pc showed much more potent effect than Vc on DT (0.1, 0.3mg; P 0.05) or SAR (0.03, 0.1, 0.3mg; P 0.05). DT and SAR were increased by Pc and Vc, and the increase in DT was inhibited by propranolol or tetrodotoxin. These results suggest that the cardiac effects of Pc or Vc may be mediated by release of norepinephrine from the synpathetic nerve endings.(Manabe M, Motomura S, Kumazawa T et al.: Positive inotropic and chronotropic effects of pancuronium and vecronium in the canine blood-pefused papillary muscle and sinoatrial node preparations. J Anesth 2: 202–206, 1988)     

Infusion of radiocontrast agents induces exaggerated release of urinary endothelin in patients with impaired renal function

Background The aim of the study was to examine the role of endothelin in radiocontrast-induced nephropathy (RCN) in patients with chronic renal failure.Methods We measured plasma endothelin-1 (ET) and the urinary excretion of endothelin-like immunoreactivity before and after infusion of radio contrast medium (CM) in patients with normal renal function (group N; n = 6; mean serum creatinine concentration, 0.8 ± 0.1 (SEM) mg/dl), and in another group, with renal dysfunction (group R; n = 6; 2.7 ± 0.5mg/dl). Half-normal saline (0.45% NaCl solution) was continuously infused in all patients for 25h, at a rate of 100ml/h; starting from 5h before the infusion of CM.Results Plasma ET in group R (5.2 ± 1.4pg/ml) was significantly higher than in group N (0.9 ± 0.3; P 0.01). Urinary endothelin excretion corrected by creatinine concentration (uET/Cr) in group R (7.9 ± 2.4mg/g Cr) was significantly higher than in group N (1.5 ± 0.4mg/g Cr; P 0.05). Urinary excretion levels of N-acetyl--d-glucosaminidase (NAG) and 2-microglobulin (2M) were also significantly higher in group R (0.8 ± 0.2mU/g Cr and 670 ± 400mg/g Cr, respectively) than in group N (0.3 ± 0.1 and 7.5 ± 2.2, respectively). After CM infusion, uET/Cr in group R significantly increased, to 10.7 ± 2.6mg/g Cr on the next day and returned to baseline level on the third day. NAG and 2M showed a similar pattern, but a significant change in NAG was observed on the second day in group R. In group N, uET/Cr, NAG, and 2M did not change after CM infusion. Plasma ET remained unchanged throughout the observation period of 4 days in both groups. No patient developed pulmonary edema or a significant rise in serum creatinine (more than 0.5mg/dl), caused by infusion of the amount of half-normal saline used.Conclusions In the present study, uET/Cr increased after the administration of CM only in the patients with renal impairment. This difference in endothelin reaction may be a causal one, in that patients with renal insufficiency readily develop RCN. The infusion of half-normal saline starting before CM infusion causes no side effects and is safe for the prevention of CM-induced acute renal failure.     

Comparison of anesthetic effects of epidural and intravenous administration of buprenorphine during operation

Thirty six patients were received epidural anesthesia with or without buprenorphine (BPN) during upper abdominal surgery. They were divided into three groups of 12 patients as follows; G-I received 20ml of 1% lidocaine epidurally, G-II received 20ml of 1% lidocaine epidurally and 0.6mg BPN intravenously, G-III received 20ml of 1% lidocaine with 0.6mg BPN epidurally. Additional 5ml of 1% lidocaine was given to any patient if systolic blood pressure or heart rate increased 10% compared to control value. Trachea was intubated following anesthetic induction with thiopental. The lungs were ventilated with a mixture of N₂O/O₂ (33%) and pancuronium was used for muscle relaxation. The total required doses of lidocaine in G-II and G-III were decreased 60% compared to control group (G-I) (P 0.05). The mean period of time until the first administration of pentazocine for postoperative pain was 13 ± 10hr (mean ± SD) in G-II and 19 ± 24hr in G-III compared to 5 ± 4hr in G-I (P 0.001). The dose of the administration of pentazocine that was required for pain relief during the first 48 postoperative hr in G-III was 54 ± 10mg (mean ± SD) compared to 150 ± 21mg in G-I (P 0.02) and 106 ± 28mg in G-II (P 0.05). Recovery from anesthesia in G-III was more rapid than that in G-I (P 0.05). The Pa_{CO 2} values in G-II and G-III increased 15% compared to control group at about 4hr and 8hr after administration of BPN, but any clinical treatment was not needed for them. Nonrespiratory side effects, e.g., nausea, vomiting, fatigue and headache, were comparably common in all groups. Mild hematuria associated with acute hypotension occurred in two patients in G-II (17%) immediately after the intravenous injection of 0.6mg of BPN. The results showed that 0.6mg of BPN given epidurally demonstrated better anesthetic and more potent postoperative analgesic effects and lesser side effects than 0.6mg of BPN given intravenously in patients undergoing upper abdominal surgery.(Yonemura E, Fukushima K.: Comparison of anesthetic effects of epidural and intravenous administration of buprenorphine during operation. J Anesth 4: 242–248, 1990)     

Cyclic alteration in the anticonvulsant effect of nitrous oxide in rats

The anticonvulsant action of nitrous oxide and its time course were studied in rats. Bicuculline, a GABA-receptor antagonist, was administered intravenously at a rate of 0.2mg·kg^–1·min^–1 during exposure to air (n = 60) or 75% nitrous oxide in oxygen (n = 80). The convulsant dose of bicuculline was determined. The rats were divided into subgroups according to the duration of exposure to air or nitrous oxide, from 0 to 120min at 15min intervals. Although the convulsant dose of bicuculline was consistent in the air group (1.03 ± 0.06mg·kg^–1, mean ± SEM), it showed two peaks at 30- and 90min exposures to nitrous oxide. The threshold dose in the nitrous oxide group was significantly higher than in the air group at only 15- and 30min exposures (1.50 ± 0.16, 2.15 ± 0.25mg·kg^–1, respectively, P 0.05). We conclude that nitrous oxide has an anticonvulsant action against bicuculline-induced seizure, and that a cyclic nature exists in its action.(Shingu K, Osawa M, Mori K: Cyclic alteration in the anticonvulsant effect of nitrous oxide in rats. J Anesth 4: 309–312, 1990)     

Hospital Readmissions Following Abdominal Aortic Aneurysm Repair

In-hospital outcomes associated with abdominal aortic aneurysm (AAA) repair are well described. However, little is known about post-discharge readmission rates, lengths of stay, associated mortality, and costs. We examined 206 consecutive patients who underwent AAA repair at two American hospitals between 1998 and 2000. Index hospitalization and 6-month readmission data were extracted from a resource and cost accounting system used by both hospitals. Among the 206 patients, 183 survived until discharge (mortality rate 11.2%). Among the surviving patients, 38 (21.0%) were readmitted within 6 months. Half of the readmissions occurred within two weeks of discharge, with patients presenting with a diverse array of complications. Nonelective repair and diabetes mellitus were independent predictors of hospital readmission (OR=2.83, 95% CI=1.25-6.40, p=0.01; OR=6.60, 95% CI=1.02-42.4, p=0.047, respectively). For each readmission, the mean length of stay was 10.7±2.5 days and the mean cost was $13,397±3,381. The cumulative number of hospital days during the 6 months post-discharge was 17.7±3.5 days for each readmitted patient and the mean per-patient total cost was $23,262±5,478. The mortality rate among readmitted patients was 13.2%. Overall, readmissions following AAA repair accounted for a cost >50% over and above the cost of the readmitted patients index hospitalization. Hospital readmissions are common during the 6 months following AAA repair. Patients who are readmitted experience long lengths of stay and high mortality rates, and their care incurs high costs.Dr. Eisenberg is a Physician-Scientist of the Quebec Foundation for Health Research. Dr. Pilote is a Physician-Scientist of the Canadian Institutes for Health Research.     

The effect of vagal afferent on total vascular compliance in rats

This study was designed to investigate the effect of vagal afferent stimulation on total vascular compliance (TVC). Rats were anesthetized with sodium pentobarbital and artificially ventilated, TVC was determined together with stressed and unstressed blood volumes by measuring mean circulatory filling pressure (Pmcf) at three different levels of circulating blood volume. Measurements was repeated with the intact vagus, after vagotomy and during stimulation of vagal afferents. Vagotomy caused no change in TVC, Pmcf, and stressed and unstressed blood volumes. On the other hand, electrical stimulation of the vagal afferents for 30sec increased TVC from 3.03 ± 0.51 to 3.39 ± 0.44ml·mmHg^–1·kg^–1 (P 0.05) and decreased Pmcf from 7.83 ± 1.40 to 7.22 ± 1.21mmHg (P 0.05). Neither stressed nor unstressed blood volume was changed by vagal stimulation. These results indicate that excitation of vagal afferent causes venodilation and increases TVC without changing stressed and unstressed blood volumes.(Kinoshita T: The effect of vagal afferent on total vascular compliance in rats. J Anesth 7: 198–205, 1993)     

Changes of local brain tissue oxygen pressure after vasopressin during spontaneous circulation

Summary. Background. Brain tissue oxygen pressure (PbtO₂) correlates to cerebral blood flow (CBF) during spontaneous circulation, with one important regulator being nitric oxide (NO). Although it is established that arginine vasopressin (AVP) improves CBF and global cerebral oxygenation during cardiopulmonary resuscitation, it is unknown whether similar beneficial effects are present during spontaneous circulation. The purpose of this study was to investigate the effects of AVP with and without pre-treatment with the NO synthase inhibitor N-omega-nitro-L-arginine methyl ester (L-NAME) on local brain tissue oxygenation in a beating heart model.Methods. Following approval of the Animal Investigational Committee, nine healthy piglets underwent general anaesthesia, and were instrumented with a probe in the cerebral cortex to measure PbtO₂. Each animal was assigned to receive AVP (0.4U·kg^–1), and after a wash-out period, L-NAME (25mg·kg^–1 over 20min) followed by AVP (0.4U·kg^–1). After each AVP administration, nitroglycerine (25µg·kg^–1 over 1min) as a NO donor was infused to test the vascular reactivity independently from NOS inhibition.Findings. Three minutes after administration of AVP, PbtO₂ increased significantly (P<.05; mean±SEM, 31±11 versus 43±14mmHg, +39%), compared with baseline. After pre-treatment with L-NAME, the changes of PbtO₂ after AVP were not significant (32±11 versus 28±10, –13%) when compared with the baseline.Conclusion. In this beating heart porcine model, local brain tissue oxygenation was improved after AVP alone, but not after inhibition of NO synthesis with L-NAME.     

68. Keramik-Traizrippen-Prothesen ohne Zement

Zusammenfassung Zur Vermeidung aseptischer Prothesenlockerung infolge Zementbruches wurde die zementfrei implantierbare Tragrippen-Endoprothese mit dem biomechanischen Verankerungsprinzip der Oberflächenvergrößerung und damit Druckreduzierung entwickelt. Darlegung der Technologie, der verwendeten Aluminiumoxydkeramik Biolox und der neuen Metallegierung Endocast. Hinweis auf die tierexperimentelle Prüfung und Operationstechnik sowie 4 1/2 jährige klinische Erfahrung mit Ergebnisstatistik. Eignung insbesondere für jüngere Patienten.     

Factors influencing metacarpal bone mineral density in adults with cerebral palsy

Several studies have examined bone mineral density (BMD) and related factors in children with cerebral palsy, but there are no such studies of adults with cerebral palsy. We evaluated BMD in 123 institutionalized adults (51 men aged 21–41 years and 72 premenopausal women aged 24–46 years) with cerebral palsy, and examined the associations of BMD with mobility level, use of anticonvulsant drugs, and abnormal calcium metabolism status. Hand radiographs were used to measure BMD of the second metacarpal bone (mBMD). Body weight (kg), height (m), and body mass index (BMI) were recorded. Serum calcium, phosphate, and alkaline phosphatase were measured. Abnormal calcium metabolism, defined as calcium 8.5mg/dl, phosphate 2.6mg/dl, or alkaline phosphatase 260U/l, was identified in 28% of the men and 31% of the women. Multiple regression analysis showed that the use of anticonvulsant drugs was significantly associated with lower mBMD in both sexes. Higher alkaline phosphatase level was significantly associated with lower mBMD in men. Mobility level (ambulation) was significantly associated with higher mBMD in women. Neither age nor BMI correlated with mBMD. Our findings indicated poor bone health status in adults with cerebral palsy and the existence of several factors that could affect bone metabolism in these patients.     

Bench test assessment of the new Raumedic Neurovent-P ICP sensor: a technical report by the BrainIT group

Summary. Background. In clinical practice, fiberberoptic and piezo-electric ICP probes are often used for measuring intracranial pressure (ICP). A number of similar technologies, although performing well in bench test studies, have been shown to exhibit unacceptable zero drift, fragility or both during trials conducted under clinical conditions. Recently, a new technology has become available, the Neurovent-P (Raumedic AG+CO, Raumedic, Germany). As a pre-requisite for a clinical trial, we have conducted and report on bench test studies to confirm the manufacturers long term zero-drift performance for this technology.Method. In a test rig static tests (recording of 20mmHg pressure) and dynamic tests, ranging from 5 to 50mmHg have been performed.Findings. 10 ICP probes have been tested for a total of 60 days. All the catheters, after the connection with the ICU monitor displayed a static pressure of 0±1mmHg and did not required pre-insertion alteration. At five days, mean zero drift was 0.6±0.9mmHg. Overall, zero drift ranged from 0 to 2mmHg. At a fixed static pressure of 20mmHg, the mean recorded value was 20.6±0.8mmHg, ranging from 19 to 23mmHg. A regression analysis of the relationship between the applied pressure and the recorded pressure during the dynamic tests of the 10 catheters yielded a correlation coefficient R² of 0.997. Applying the Altman and Bland method to assess the bias and confidence limits for the Raumedic catheter responses during the dynamic tests against the applied gold-standard hydrostatic column pressures, the average bias of –0.66±0.85mmHg, with 95% CLs of –2mmHg and 1mmHg.Conclusions. Mean zero drift, after five days, was very small and long-term continuous recording of a stable pressure was very precise. The response at dynamic tests, i.e. the changes of pressure in a wide range, was excellent. The average bias of the Raumedic catheter compared with the hydrostatic column is very small. After this bench test, the next and most critical step will be to conduct a trial of this promising technology under more demanding clinical environment.     

Temperature and humidity of the DrÄger Cato anesthetic machine circuit

Purpose.The DrÄger Cato anesthetic machine (DrÄger, LÜbeck, Germany) effectively humidifies and warms anesthetic gases, because it has a built-in hotplate to heat the breathing system, and expired gas passes through the CO₂ absorbent three times during one breath. In the present study, we measured the temperature and absolute humidity (AH) of the anesthetic circuit in the DrÄger Cato machine with and without heat moisture exchangers (HME), and compared them with those in another anesthetic machine, the Aestiva/5 (Datex-Ohmeda, Helsinki, Finland).Methods.Forty-eight adult patients were randomly assigned to one of eight groups according to the anesthetic machine, fresh gas flow (FGF), and the use of HME (n = 6 each): Cato 0.5l·min^–1 without HME (group 1), Cato 1.0l·min^–1 without HME (group 2), Cato 0.5l·min^–1 with HME (group 3), Cato 1.0l·min^–1 with HME (group 4), Aestiva 0.5l·min^–1 without HME (group 5), Aestiva 1.0l·min^–1 without HME (group 6), Aestiva 0.5l·min^–1 with HME (group 7), and Aestiva 1.0l·min^–1 with HME (group 8). The temperature and AH of the anesthetic gases were measured with a Moiscope (S.K.I. Net, Tokyo, Japan), which was placed between the endotracheal tube and the Y-piece of the anesthetic circuit. The HME was placed between the Moiscope and the Y-piece of the anesthetic circuit. The temperature and AH of the anesthetic gases were measured at 5, 10, and 15min and then every 15min up to 150min after tracheal intubation.Results.Among the groups without HME (groups 1, 2, 5, and 6), the inspired temperatures and AH in groups 1 and 2 were significantly higher than those in groups 5 and 6 at all times during the study period (P 0.01–0.001). The inspired temperatures and AH of the groups with HME (groups 3, 4, 7, and 8), were significantly higher than those in groups 2, 5, and 6 (P 0.01–0.001). Among the groups with HME, the AH in group 3 was significantly higher than that in group 8 until the final study period.Conclusion.The present study indicates that the DrÄger Cato machine was more effective in warming and humidifying respiratory gas than the Aestiva/5, and that Aestiva/5 without HME does not reach the optimal temperature and humidity ranges, even if minimal flow anesthesia (0.5l·min^–1) is performed.     

Combined effects of Inversed Ratio Ventilation (IRV) with positive end-expiratory pressure ventilation (PEEP) on cardiorespiratory function in acute respiratory failure

Combined effects of inversed ratio ventilation (IRV) with positive end-expiratory pressure (PEEP) on cardiorespiratory function were examined in 24 patients with acute respiratory failure. Patients were divided into two groups: the IRV group (n = 12) who showed no significant increase in Pa_{O 2} with a 6cmH₂O of PEEP and PEEP group (n = 12) who were ventilated mechanically with PEEP only at maximum level of 10cmH₂O. In IRV group step-wise prolongation of the I:E ratio from 1:1.9 to 2.6:1 or 4:1 was applied as a Pa_{O 2} was improved and in PEEP group also level of PEEP was increased from 0, 5 to 10cmH₂O after one hour period irrespective of Pa_{O 2}. Inversed ratio ventilation and PEEP increased significantly Pa_{O 2}/Fi _{O 2}, the increase being observed 6hrs (I:E = 2:1) and 2hrs (10cmH₂O) after starting IRV or PEEP. Further improvement of oxygenation was not observed in IRV even if I:E ratio was prolonged up to 2.6:1 or 4:1. These results suggested that combinations of IRV with PEEP were effective and an I:E ratio of 2:1 may be optimal, and IRV is advantageous compared to PEEP, but will take more long time to improve oxygenation than PEEP.(Sari A, Toriumi T, Yamashita S, et al.: Combined effects of inversed ratio ventilation (IRV) with positive end-expiratory pressure ventilation (PEEP) on cardiorespiratory function in acute respiratory failure. J Anesth 5: 105–113, 1991)