Surgical tactics in acute mesenteric artery occlusion

Operations were performed on 52 patients for acute mesenteric embolism, between 1980 and 1988. The average age of 48 of them was 75.8 +/- 7.3 years. Only four patients were below 60 years of age. Only exploratory laparotomy was possible in 20 cases, and all of these patients died. Six of eight patients (75 per cent) did not survive embolectomy from the superior mesenteric artery. Seven of twelve patients (58 per of eleven patients (27 per cent) died after embolectomy and resection of subtotal parts of the small intestine. Death occurred also to one patient with acute iliaco-mesenteric bypass. Hence, total mortality of all 52 patients amounted to 71.1 per cent. The mortality rate for 32 patients with attempted restitutional surgery amounted to 53.1 per cent, exploratory laparotomy unconsidered. This was certainly attributable to 73 per cent of survivors of embolectomy combined with removal of somewhat extended intestinal sections. Follow-up checks in short intervals of serum lactate have proved to provide reliable diagnostic parameters and means for postoperative appraisal with a view to making an informed estimate of changes of a second-look operation for acute intestinal ischaemia. The lactate mean value for mesenteric embolism was 8.88 +/- 4.43 mmol/l. However, lactate values were normal, between 1 mmol/l and 2 mmol/l, in acute abdominal processes with non-ischaemic causes and in cases of ischaemia of extremities.(ABSTRACT TRUNCATED AT 250 WORDS)     

Continuous veno-venous haemodialysis with a novel bicarbonate dialysis solution: prospective cross-over comparison with a lactate buffered solution.

OBJECTIVE: To compare acid-base balance, lactate concentration and haemodynamic parameters during continuous veno-venous haemodialysis (CVVHD) using bicarbonate or a lactate buffered dialysate. METHODS: Design: prospective randomized cross-over design; Setting: Multicentre combined adult surgical and medical intensive care units. Patients; 26 critically ill patients starting CVVHD for acute renal failure. Interventions: Each patient to receive 48 h of bicarbonate dialysate and 48 h of lactate dialysate with the order of the 48 h block randomized at trial entry. RESULTS: The serum bicarbonate increased from baseline in both the lactate and bicarbonate groups over the first 48 h of treatment (16.3+/-1.53 to 22.2+/-1.41 mmol/l and 18.9+/-2.02 to 22.2+/-1.18 mmol/l, respectively) and continued to rise towards normal over the next 48 h after cross-over to the other dialysate. The H+ and pCO2 only trended higher in the lactate group. Unlike the acid base parameters, serum lactate levels varied depending on the dialysate composition. The patients initially randomized to the lactate dialysate had higher serum lactate levels and these tended to increase further after 48 h of dialysis from 2.4+/-0.8 to 2.6+/-0.4 mmol/l. However, in the following 48 h the lactate levels fell to 1.8+/-0.6 (P = 0.039) while patients were being treated with the bicarbonate dialysate. Similar results were seen in the patients initially randomized to the bicarbonate dialysate. Serum lactate remained stable over the first 48h (1.4+/-0.2 to 1.5+/-0.1 mmol/l) but after cross-over to the lactate dialysate increased to 3.1+/-0.7 mmol/l (P = 0.051). Overall, lactate levels were significantly higher during dialysis with lactate buffered solution than bicarbonate buffered solution (2.92+/-0.45 vs. 1.61+/-0.25 mmol/l P = 0.01). Mean arterial pressure trended higher during bicarbonate dialysis but did not reach statistical significance (lactate vs. bicarbonate; 71.1+/-3.1 vs. 81.3+/-5.8 mm Hg). Subgroup analysis of the patients with abnormal liver indices or increased lactate levels at initiation of dialysis (n = 15) revealed only a trend toward better bicarbonate control (lactate vs. bicarbonate; 22.00+/-1.73 vs. 22.86+/-1.09, P = 0.2). However, in this group with hepatic insufficiency elevations in serum lactate were even greater during lactate compared to the bicarbonate dialysis (3.39+/-0.68 vs. 1.78+/-0.42 P = 0.036). Patients who had elevations of lactate during lactate dialysis had a high mortality (6 of 7). These patients had an even greater disparity in lactate levels (4.3+/-1.4 vs. 1.3 +/-0.3) and blood pressure (68.0+/- 7.7 vs. 87.2+/-17.1) between lactate and bicarbonate dialysis. Due to small patient numbers these comparisons did not achieve statistical significance. CONCLUSION: During continuous veno venous haemodialysis a bicarbonate buffered dialysis solution provided equal acid-base control but maintained more normal lactate levels than a lactate buffered dialysis solution.     

Early and long-term prognostic value of Troponin-I after cardiac surgery in newborns and children.

BACKGROUND: Troponin-I (Tn-I) is a well-recognized early postoperative marker for myocardial damage in adults and children. The present prospective study was undertaken to investigate whether a postoperative Tn-I value higher than 35 microg/l is able to predict long-term outcome as it does in early postoperative course, after surgery for congenital heart defects (CHD). MATERIALS AND METHODS: Five hundred and twenty patients (median age 11 months; male 54.7%: 284 patients) undergoing congenital heart defect repair on cardiopulmonary by-pass were prospectively updated in our database including postoperative Tn-I values. Seventy of them (13.4%) (mean age 2.6+/-5.8 months) (70/520) experienced low output syndrome in the early postoperative period. According to the complexity of their malformations, we have arbitrarily divided these patients into two groups: group A included atrial and ventricular septal defects (13 patients), while group B included hypoplastic left heart syndrome, atrio-ventricular canal, transposition of great vessels, tetralogy of Fallot, double outlet right ventricle, truncus arteriosus, total anomalous venous return, and other combined diseases (57 patients). These patients are the object of our study. We reviewed clinical, laboratory, and echocardiographic data performed in the immediate postoperative course (within 24 h) and in the follow-up. RESULTS: In this study, 13 patients died (13/70 patients; 18.5%), 12 in group B and 1 in group A. In deceased patients, mean Tn-I value was 130+/-175 microg/l (CK-MB 570+/-280 microg/l). Conversely, survivors showed a lower mean Tn-I value (25.5+/-28.9 microg/l; CK-MB 76+/-86 microg/l). Overall, Tn-I peak value was higher than 35 microg/l in 19 patients (19/70; 27.2%); among these, 9 died (median Tn-I was 163+/-186 microg/l), whereas in survivors it was 73.4+/-37 microg/l (p=0.37). The remaining four patients who died had a median Tn-I value of 21 microg/l. When Tn-I exceeded 35 microg/l (>100 microg/l in two cases), at echocardiogram a severely depressed cardiac function was evident. Nevertheless, at long-term follow-up (12+/-6 months), the echocardiogram showed an enhanced cardiac performance with an ejection fraction of 70+/-8.5% in all; none of these patients presented with worsened ventricular function. CONCLUSION: Cardiac Tn-I is a specific and sensitive marker of myocardial injury after cardiac surgery and it may predict early in-hospital outcomes. However, by long-term echocardiographic analysis, cardiac Tn-I value looses its prognostic significance and therefore it is not a predictor of long-term ventricular dysfunction.     

Interest of D-lactate as a colic hypoperfusion marker during aortic abdominal aneurysm surgery

OBJECTIVE: D-lactate is the dextrogyre form of the lactate usually measured in intensive care. Its bacterial origin should make it a marker of translocation during gut ischemia. The aim was to test D-lactate as a postoperative marker of colic hypoperfusion measured during aortic surgery. STUDY DESIGN: Prospective observational cohort study. PATIENTS AND MEASUREMENTS: Patients operated for abdominal aortic aneurysm. Two groups were stratified on inferior mesenteric arterial residual pressure (IMArP) measured during the surgery: Colic hypoperfusion during surgery (CHs) group: patients with an IMArP < 40 mmHg. Control Group: patients with an IMArP > or = 40 mmHg. Baseline data such as age, duration of aortic clamping and severity score (IGS II) were collected. The D-lactate was measured in postoperative at admission time in ICU and then daily. D-lactate(max) defined the maximum value of D-lactate for one patient. MAIN RESULTS: Twenty-nine patients were included, 23 in the control group and 6 in the CHs group. Groups were comparable at baseline. D-lactate(max) was significantly higher in the CHs group (median: 0.13 mmol/l; min-max: 0.03-0.9 mmol/l) than in the control group (0.03; 0-0.26 mmol/l, p=0.007). CONCLUSION: D-lactate could be postoperative marker of colic hypoperfusion measured during surgery for abdominal aortic aneurysm.     

Washing of irradiated red blood cells prevents hyperkalaemia during cardiopulmonary bypass in neonates and infants undergoing surgery for complex congenital heart disease.

OBJECTIVE: High concentrations of potassium and lactate in irradiated red cells transfused during cardiopulmonary bypass may have detrimental effects on infants and neonates undergoing cardiac surgery. The effects of receiving washed and unwashed irradiated red cells from the cardiopulmonary circuit on serum potassium and lactate concentrations were compared. METHODS: The study population included neonates and infants undergoing heart surgery for complex congenital heart disease. A control group (n=11) received unwashed irradiated red cells and the study group (n=11) received irradiated red cells washed in a cell saver (Dideco Electa) using 900ml of 0.9% saline prior to pump priming. Potassium and lactate concentrations were compared before, during and after bypass. RESULTS: Washing irradiated red cells reduced donor blood [potassium] from>20 to 0.8+/-0.1mmol/l, and [lactate] from 13.7+/-0.5 to 5.0+/-0.3mmol/l (p<0.001). The resulting prime had significantly lower [potassium] and [lactate] than the unwashed group (potassium 2.6+/-0.1 vs 8.1+/-0.4mmol/l, p<0.001; lactate 2.6+/-0.2 vs 4.6+/-0.3mmol/l, p<0.001). Peak [potassium] in the unwashed group occurred 3 minutes after going on bypass (4.9+/-0.3mmol/l) and during rewarming (4.9+/-0.4mmol/l). These were significantly higher than the washed group (3.1+/-0.1, p<0.001 and 3.0+/-0.1mmol/l, p<0.001). The [potassium] was greater than 6.0mmol/l for 4 out of these 11 unwashed patients compared with none of the washed group. Immediately post-bypass the washed group had significantly lower serum [potassium] (3.2+/-0.1 vs 4.2+/-0.2mmol/l, p=0.002). There was no significant difference in [lactate] between groups during and after cardiopulmonary bypass. CONCLUSIONS: The washing of irradiated red cells reduces potassium and lactate loads and prevents hyperkalaemia during cardiopulmonary bypass. The washing of irradiated red cells should be considered in neonates and infants undergoing cardiac surgery for complex congenital heart disease.     

Is an increase in lactate concentration associated with cardiac dysfunction after the Fontan procedure?

PURPOSE: To investigate how blood lactate concentration changes in the early postoperative course after the Fontan procedure, and whether such a change is associated with postoperative hemodynamics. MATERIALS AND METHODS: Eight pediatric patients who underwent the Fontan procedure for congenital heart disease were included. Enrollment criteria were body weight >10 kg and staged Fontan procedure following the bidirectional Glenn procedure. Blood lactate concentration and central venous oxygen saturation (SvO2) were measured at five points: before skin incision, upon intensive care unit (ICU) admission, 15 minutes before, 15 minutes after, and 2 hours after extubation. Cardiac index (CI) was continuously monitored using the pulse contour technique. RESULTS: Lactate concentration increased in the ICU, peaking from 15 minutes before (2.7+/-1.3 mmol/L) to 15 minutes after (3.0+/-1.3 mmol/L) extubation. Values returned to normal parameters (1.0+/-0.1 mmol/L) within 48 hours. The CI values were also higher immediately after extubation (4.0+/-0.6 L/min/m2) than at ICU admission (3.3+/-0.6 L/min/m2) and before extubation (3.6+/-0.6 L/min/m2) (p=0.012). No significant change in central SvO2 or blood pressure (BP) was evident during the study period. CONCLUSION: In the early postoperative period after the Fontan procedure, blood lactate concentration increased temporarily around the time of extubation but the increase was not associated with hemodynamic deterioration.     

Paradoxical increase in arterial hydrogen ion concentration in patients with hepatorenal failure given lactate-based fluids

We have investigated lactate intolerance in nine patients with acute hepatorenal failure during 21 machine haemofiltration treatments using a lactate based replacement solution. In all cases hyperlactataemia occurred, the mean arterial lactate increased from 1 +/- 0.2 mmol/l (mean +/- SEM) prior to treatment to 3.2 +/- 0.3 mmol/l at 1 h (P less than 0.01), 4.2 +/- 0.4 mmol/l at 2 h (P less than 0.01), 4.2 +/- 0.4 mmol/l at 3 h (P less than 0.01) and 3.9 +/- 0.4 mmol/l (P less than 0.01) post-treatment. There were correlations between the maximum increase in blood lactate and both the change in arterial hydrogen ion concentration (r = 0.71, P = 0.001) and the mean arterial blood pressure prior to starting treatment (r = -0.57, P = 0.007). During eight of the treatments (38%), the arterial hydrogen ion concentration increased. This group showed increased lactate intolerance in association with a lesser pretreatment mean arterial pressure. The administration of exogenous lactate to patients with hepatorenal failure who are at, or near to, the threshold of their own endogenous lactate metabolism can result in an increase in hydrogen ion concentration rather than the expected decrease, and therefore lactate-based dialysate solutions are best avoided.     

Long-term outcome after surgical treatment of arterial lesions in Behçet disease

OBJECTIVE: Surgical treatment of arterial lesions associated with Beh?et disease (BD) is often complicated by graft occlusion and recurrence of aneurysms. The purpose of this study was to clarify the long-term outcome of surgical intervention for arterial involvement in BD. METHODS: Ten patients with BD (9 men, 1 woman) who underwent surgical treatment for arterial aneurysms between 1980 and 2004 were included in the study. The age of patients at the first operation ranged from 36 to 69 years (mean, 50.4 +/- 9.0 years). The mean period between the onset of BD and that of arterial manifestations was 8.0 +/- 5.0 years. We retrospectively reviewed their postoperative courses, including survival, graft occlusion, formation of anastomotic false aneurysms, and the development of aneurysms at different sites. The Kaplan-Meier method was used to calculate the chronologic incidence of complications after surgery. RESULTS: The mean follow-up period was 133 +/- 92 months, ranging from 5 to 285 months. One patient died of rupture of a dissecting aortic aneurysm after undergoing several surgical interventions for multiple aneurysms. There were five graft occlusions among 21 grafts. The cumulative primary graft patency rate in the infrainguinal region was 83.9% at 3 years. Five anastomotic false aneurysms formed among 49 anastomoses between grafts and host arteries. The overall cumulative incidence of formation of anastomotic pseudoaneurysm was 12.9% at 5 and 10 years. All of them formed within 18 months after surgery. Development of new aneurysms in different arteries was observed in two patients. CONCLUSIONS: Early occurrence of anastomotic false aneurysm is characteristic of BD. Further investigation is necessary to establish effective postoperative treatment.     

Clinical and economic evaluation of the trellis thrombectomy device for arterial occlusions: preliminary analysis

OBJECTIVES: This preliminary study examined the technical efficacy, safety, and cost of treating arterial occlusions with a single device that combines pharmacologic and mechanical thrombolysis. METHODS: The technical success, bleeding complications, and costs for the first 26 consecutive patients in whom lower extremity ischemia was treated with the Trellis infusion catheter (TIC) were analyzed. Procedure time, thrombolytic infusion time, technical success, bleeding complications (major and intracranial hemorrhage), interventional suite time, and 30-day amputation-free survival were evaluated. RESULTS: 15 of 26 patients (58%) who received treatment with the TIC had acute arterial occlusions, and 11 of 26 patients (42%) had nonacute arterial occlusions. Nineteen of 26 patients (73.1%) received treatment of an infrainguinal occlusion, and 7 of 26 patients (26.9%) received treatment of a suprainguinal occlusion. Lower extremity native arteries were treated in 18 of 26 patients (69%), and lower extremity bypass grafts in 8 of 26 patients (31%). The technical success rate with TIC treatment was 92%, and the 30-day amputation-free survival rate was 96%. There was no difference in technical success or amputation-free survival rate between acute versus nonacute arterial occlusions, native artery versus bypass grafts, and suprainguinal versus infrainguinal arterial occlusions. Procedure time was 2.1 +/- 0.9 hours, and infusion time was 0.3 +/- 0.2 hours. There were no bleeding complications; however, 3 of 26 patients (11.5%) required further intervention to treat distal embolization. The overall mean cost for patients with TIC treatment was $3216 +/- $1740. CONCLUSIONS: Early results of TIC treatment in patients with arterial occlusions suggest that it is as effective as traditional catheter-directed thrombolysis. Furthermore, there were no bleeding complications, likely the result of TIC requiring shorter procedure and infusion times.     

Vascular manifestations of Behçet's disease. Eighteen cases among 140 patients

OBJECTIVES: To describe the features, prognosis, and treatment of vascular involvement in Beh?et's disease (BD). PATIENTS: Among 140 patients with BD seen at the H?tel-Dieu Hospital in Beirut between 1980 and 2000, 18 (13%) had vascular involvement and were included in this retrospective study. All these patients fulfilled International Study Group criteria for BD. RESULTS: Men with BD were more likely to have vascular involvement (13/77, 17%) than women (5/63, 8%) (P = 0.12) and were younger at diagnosis of vascular disease (32 +/- 7 vs. 36 +/- 7.5 years; P < 0.01). Many patients had vascular disease at more than one site: 17 had thrombophlebitis, 10 had arterial thromboses, and one had an aneurysm. Thrombophlebitis was more common in men (82% vs. 18%; P < 0.03) and arterial occlusion in women (70% vs. 30%; P > 0.05). Caval thrombosis and arterial occlusions were the most serious complications. Combined treatment with glucocorticoids, anticoagulants, and immunosuppressants was effective in superior vena cava syndrome and extracranial arterial occlusion. CONCLUSION: Vascular manifestations of BD are common in Lebanon, particularly venous lesions. Aneurysms are seen less often than arterial occlusions. Medical treatment may be sufficient in superior vena cava syndrome and arterial occlusion.     

Intestinal ischemia associated with cardio-pulmonary-bypass surgery: a life threatening complication

Intestinal ischemia following open heart surgery is rare but nevertheless extremely dangerous and the causes are still unclear. The purpose of this study was to evaluate the factors influencing the occurrence and outcome of patients with this complication. At our institution between 1985 and 1989 1712 patients underwent open heart surgery and 4 female patients suffered from intestinal ischemia. The early mortality was 2.5% for the whole group and 100% for the group with intestinal ischemia. All these 4 patients were elderly and had a history of hypertension and hyperlipoproteinemia. Three of the four patients with intestinal ischemia had various risk factors for thromboembolic events such as pre-existing occlusive arterial disease and cardiac dysrhythmias or had a complicated postoperative course. In two patients an enormous increase in serum lactate to over 10 mmol/l occurred prior to the intestinal ischemia. We therefore consider advancing age, female gender and a susceptibility for thromboembolic events as important risk factors for the development of intestinal ischemia. A serum lactate over 10 mmol/l should lead to an aggressive diagnostic and therapeutic approach including exploratory laparotomy.     

Blood lactate levels during fast-track cardiac anesthesia

BACKGROUND: Lactate is a very sensitive marker of outcomes in critically ill patients. The aim of this study was to investigate the significance of blood lactate measurement during fast-track cardiac anesthesia. METHODS: We examined arterial blood lactate levels of 12 patients following coronary artery bypass graft surgery under intermittent aortic cross clamping with fast-track cardiac anesthesia. Anesthesia was induced with propofol and fentanyl, and maintained with propofol, fentanyl (total 400-1000 micrograms) and isoflurane. Blood samples were collected from a radical artery catheter. RESULTS: At the termination of the extracorporeal circulation, the blood lactate was 10.3 +/- 2.0 (7.4-12.5) mmol.l-1. This value decreased slowly to 1.5 +/- 0.4 mmol.l-1 on the second postoperative day. All patients were extubated within 4 hours after surgery. Vital signs were stable, and no cardiac events occurred perioperatively. CONCLUSIONS: A continuous decline in blood lactate levels was related to a favorable postoperative course. Further research might be required to prevent transient hyperlactecemia at the end of cardiopulmonary bypass.     

介入疗法在急性肢体动脉闭塞治疗中的应用价值

目的探讨介入疗法在急性肢体动脉闭塞治疗中的应用价值。方法回顾性总结28例急性肢体动脉闭塞介入治疗经验。采用经皮血管腔内成形术和动脉内溶栓术治疗上肢动脉闭塞5例、腹主动脉下段闭塞1例、下肢动脉闭塞22例。结果经术后4个月~9年临床观察,急性单段动脉闭塞血管再通率为100%(8/8例)、多段动脉闭塞血管再通率为80%(16/20例),总血管再通率为85.71%(24/28例)。结论介入疗法是治疗急性肢体动脉闭塞的一种有效方法,值得推广应用。     

Serum lactate level has prognostic significance after pediatric cardiac surgery

OBJECTIVE: The determination of postoperative course after cardiac surgery has always been a challenging issue. It is more sophisticated in the pediatric age group. The aim of this investigation was to identify whether increased concentrations of lactate in arterial blood has a predictive value for postoperative morbidity and mortality after heart surgery. METHODS: From May 2002 to June 2003, 60 infants operated on at the authors' institution were included in this prospective study. The patients were divided into 2 groups according to their respective postoperative serum lactate values. After the stabilization period in the intensive care unit (first 3 hours postoperatively), samples for serum lactate were obtained from arterial blood at 3 (t1), 6 (t2), and 12 hours (t3) postoperatively. The patients were subdivided into 2 groups according to their respective mean serum lactate values. A value of 4.8 mmol/L (3 times the normal upper limit) was chosen as a threshold for serum lactate. The patients with a mean value of greater than 4.8 mmol/L (group 1) were compared with the remaining group of patients (group 2). The relationship between serum mean lactate level and intraoperative and postoperative clinical variables was evaluated. RESULTS: Among the patients in this study, 26 (43.3%) had a serum mean lactate level more than 4.8 mmol/L and 34 (56.7%) had a level of 4.8 mmol/L or less. Age, aortic cross-clamping time, cardiopulmonary bypass time, and the lowest hematocrit during cardiopulmonary bypass were significant variables that influenced the postoperative serum mean lactate level. Six patients died in the postoperative period and 54 infants survived. The hospital mortality was significantly higher in group 1 than in group 2 (19.0% v 2.9%; p = 0.037, kappa = 0.179). Multivariate analysis revealed that serum mean lactate level correlated significantly with inotrope score, intubation time, and intensive care unit stay. CONCLUSIONS: Blood lactate concentration of 4.8 mmol/L or higher during the early postoperative hours identifies a group of patients with increased risk of postoperative morbidity and mortality.     

When is urokinase treatment an effective sole or adjunctive treatment for acute limb ischemia secondary to native artery occlusion?

BACKGROUND: Intra-arterial thrombolytic therapy is currently a therapeutic option for the treatment of acute limb ischemia. A recent large prospective randomized trial (TOPAS) comparing lytic therapy and operative intervention showed that both forms of treatment had similar results in terms of amputation-free survival. However, the exact role for lytic treatment is unclear. METHOD: Over a 4-year period we treated 60 cases of acute limb ischemia in 57 patients secondary to native artery occlusion with thrombolytic therapy with urokinase. All patients were evaluated at 1 week, 1 month, and then at 3-month intervals posttreatment. Follow-up evaluations included pulse examination, pulse volume recordings, and duplex examinations to confirm arterial patency. No patients were lost to follow-up with a range of 8 to 54 months (mean 26). RESULTS: Of these 60 native arterial occlusions, complete lysis was achieved in 46 cases (76%). Of these 46 cases, 18 required lysis only, 19 cases (9 iliac, 7 superficial femoral artery (SFA), and 3 popliteal) required angioplasty of lesions uncovered by clot lysis, and 9 patients had lysis and angioplasty of iliac arteries followed by infrainguinal bypasses. Eight of the 57 patients (14%) who had been asymptomatic presented with symptoms limited to new onset claudication, all of which were successfully lysed. Cumulative patency for the 43 successful cases was 90% +/- 5% at 1 year and 75% +/- 4% at 2 years. The 1-year amputation-free survival for all native artery occlusions was 85% +/- 6%. CONCLUSION: Thrombolysis with urokinase simplified the treatment of native arterial occlusion proving to be the sole therapy in 18 (29%) patients or a valuable adjunct by facilitating the angioplasty of arterial lesions and avoiding open surgery in 60% of patients treated. In addition, the correction of inflow lesions reduced the magnitude of required subsequent bypass procedures to achieve limb salvage. In conclusion, successful thrombolysis of native artery occlusion provided durable arterial patency and limb salvage, particularly in patients with new onset claudication.     

Predictive factors of low HCO3- levels in peritoneal dialysis patients

BACKGROUND: Metabolic acidosis is a major metabolic abnormality in end-stage renal disease (ESRD) and alkali is provided with dialysis treatment to patients on chronic peritoneal dialysis (CPD) to keep their acid-base balance within normal serum HCO3- levels. METHODS AND RESULTS: We examined the levels of venous serum HCO3- in 163 patients on CPD and the predictive factors for HCO3- levels low enough to indicate metabolic acidosis. The mean value for HCO3- was 26+/-2.4 mmol/l and for anion gap was 13.1+/-3.1 mEq/l. A serum bicarbonate concentration of less than 24 mmol/l, compatible with metabolic acidosis, was observed in 13.5% of the patients. In a multivariate analysis HCO3- levels were directly correlated with older age and use of CaCO3- as phosphate binders, and inversely associated with serum potassium, the use of sevelamer and low lactate dialysis solutions. Higher serum urea levels, the use of low lactate solutions and sevelamer instead of CaCO3 were significantly predictive factors for HCO3- levels < 24 mmol/l. CONCLUSIONS: Venous HCO3- and anion gap values were within the normal ranges in stable CPD patients. In 13.5% of them, however, chronic metabolic acidosis was observed based on venous HCO3- levels < 24 mmol/l. Dietary protein intake, the use of sevelamer and low (35 mmol/l) concentration of lactate in dialysis solutions are important predictive factors for chronic metabolic acidosis in these patients.     

Acute arterio-venous fistula occlusion decreases sympathetic activity and improves baroreflex control in kidney transplanted patients.

BACKGROUND: The acute bradycardia induced by the occlusion of an arteriovenous fistula (AVF), known as the Nicoladoni-Branham sign, is considerably larger than that which occurs during carotid sinus massage. This suggests increased arterial baroreflex sensitivity during acute AVF occlusion. Moreover, the influence of acute AVF occlusion on muscle sympathetic nerve traffic (MSNA, by microneurography) is unknown. We therefore assessed the effects of acute AVF occlusion on baroreflex sensitivity and on MSNA in patients with stable functional kidney grafts and patent AVF. METHODS: We measured blood pressure (BP), MSNA (n = 11), heart rate (HR), cardiac output (CO) and arterial baroreflex sensitivity (n = 18) at baseline and during acute, 30-s pneumatic AVF occlusions in 23 renal transplanted recipients. RESULTS: During the first 5 s of the AVF occlusion, mean BP increased from 98+/-4 to 112+/-4 mmHg (P<0.0001) while MSNA decreased to 28+/-5% of baseline values (P<0.0001) and HR decreased from 71+/-3 to 61+/-3 b.p.m. (P<0.0001). The largest increases in BP were accompanied by the most marked decreases in MSNA (r = -0.79, P = 0.003) and HR (r = -0.49; P = 0.01) during the first 5 s of the AVF occlusion. During AVF occlusion baseline CO of 6.9+/-0.3 decreased to 5.6+/-0.3 l/min (P<0.0001) while baroreflex sensitivity increased from 10+/-1 to 17+/-2 ms/mm Hg (P<0.001). CONCLUSIONS: Arterial baroreceptor activation and increased arterial baroreflex sensitivity decrease heart rate during AVF occlusion. In addition, our study is the first to demonstrate that arterial baroreflex activation decreases sympathetic nerve traffic during the Nicoladoni-Branham sign.     

D-dimer testing in patients with suspected acute thromboembolic occlusion of the superior mesenteric artery

BACKGROUND: There is no accurate non-invasive method available for the diagnosis of acute thromboembolic occlusion of the superior mesenteric artery (SMA). The aim of this study was to assess the diagnostic properties of the fibrinolytic marker D-dimer. METHODS: From September 2000 to April 2003 consecutive patients aged over 50 years admitted to hospital with acute abdominal pain were studied. Patients with possible acute SMA occlusion at presentation had blood samples taken within 24 h of the onset of the pain for analysis of D-dimer, plasma fibrinogen, activated partial thromboplastin time, prothrombin time and antithrombin. The value of D-dimer testing to diagnose SMA occlusion was assessed by means of likelihood ratios. RESULTS: Nine of 101 patients included had acute SMA occlusion. The median D-dimer concentration was 1.6 (range 0.4-5.6) mg/l, which was higher than that in 25 patients with inflammatory disease (P = 0.007) or in 14 patients with intestinal obstruction (P = 0.005). The combination of a D-dimer level greater than 1.5 mg/l, atrial fibrillation and female sex resulted in a likelihood ratio for acute SMA occlusion of 17.5, whereas no patient with a D-dimer concentration of 0.3 mg/l or less had acute SMA occlusion. CONCLUSION: D-dimer testing may be useful for the exclusion of patients with suspected acute SMA occlusion.     

Intracerebral microdialysis in clinical practice: baseline values for chemical markers during wakefulness, anesthesia, and neurosurgery

OBJECTIVE: The study was undertaken to measure baseline values for chemical markers in human subjects during wakefulness, anesthesia, and neurosurgery, using intracerebral microdialysis. METHODS: Microdialysis catheters were inserted into normal posterior frontal cerebral cortex in nine patients who were undergoing surgery to treat benign lesions of the posterior fossa. The perfusion rate was 1.0 microl/min during anesthesia/neurosurgery and the early postoperative course and 0.3 microl/min during the later course. Bedside biochemical analyses of glucose, pyruvate, lactate, glycerol, glutamate, and urea were performed before, during, and after neurosurgery. After the bedside analyses, all samples were frozen for subsequent high-performance liquid chromatographic analyses of amino acids. RESULTS: The following baseline values were obtained during wakefulness (perfusion rate, 0.3 microl/min): glucose, 1.7+/-0.9 mmol/L; lactate, 2.9+/-0.9 mmol/L; pyruvate, 166+/-47 micromol/L; lactate/pyruvate ratio, 23+/-4; glycerol, 82+/-44 micromol/L; glutamate, 16+/-16 mmol/L; urea, 4.4+/-1.7 mmol/L. Marked increases in the levels of all chemical markers were observed at the beginning and end of anesthesia/surgery. CONCLUSION: The study provides human baseline levels for biochemical markers that can presently be measured at the bedside during neurointensive care. In addition, some changes that occurred under varying physiological conditions are described.     

Splanchnic perfusion during controlled hypotension combined with acute hypervolemic hemodilution: a comparison with combination of acute normovolemic hemodilution-gastric intramucosal pH study

STUDY OBJECTIVE: To evaluate the effect of controlled hypotension combined with acute hypervolemic or normovolemic hemodilution on the splanchnic perfusion in the clinical setting. DESIGN: Randomized, prospective study. SETTING: Inpatient surgery at Nagasaki Rosai Hospital. PATIENTS: 28 ASA physical status I and II patients scheduled for total hip arthroplasty.Interventions: Patients were randomly divided into two groups. Group A (n = 14) received controlled hypotension with acute normovolemic hemodilution (ANH). Group B (n = 14) received controlled hypotension with acute hypervolemic hemodilution (HHD). ANH was produced by drawing approximately 1000 mL of blood and replacing it with the same amount of 6% hydroxyethyl starch solution (HES). HHD was produced by preoperative infusion of 1000 mL of 6% HES without removing blood. The final hematocrit values were 24+/-2% (mean +/- SD) in Group A and 25+/-3% in Group B. Controlled hypotension was induced with prostaglandin E1 (PGE1) to maintain mean arterial blood pressure at 55 mmHg for 80 minutes. MEASUREMENTS: Measurements included the gastric pH (pHi), the arterial blood pH (pHa), and plasma lactate. These indices were measured before hemodilution, after hemodilution, 80 minutes after starting hypotension, 60 minutes after recovery from hypotension, and on the first postoperative day. The value of pHi was measured by tonometric method. MAIN RESULTS: The pHa and lactate values showed no change in either group A or group B throughout the time course. Gastric pHi values in group A showed a significant decrease from 7.424+/-0.033 to 7.335+/-0.038 (p<0.05) after hemodilution, whereas it showed no further decrease at 80 minutes after starting hypotension and 60 minutes after recovery from hypotension. The pHi values in group B showed no significant decrease after hemodilution and no further change at 80 minutes after starting hypotension. CONCLUSIONS: HHD does not impair splanchnic perfusion, whereas ANH might cause impairment. Controlled hypotension with prostaglandin E1 would not impair splanchnic perfusion in combination with either HHD or ANH.