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.

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.

Aprotinin and transfusion requirements in orthotopic liver transplantation: a multicentre randomised double-blind study. EMSALT Study Group

BACKGROUND

Intraoperative hyperfibrinolysis contributes to bleeding during adult orthotopic liver transplantation. We aimed to find out whether aprotinin, a potent antifibrinolytic agent, reduces blood loss and transfusion requirements.

METHODS

We did a randomised, double-blind, placebo-controlled trial in which six liver-transplant centres participated. Patients undergoing primary liver transplantation were randomly assigned intraoperative high-dose aprotinin, regular-dose aprotinin, or placebo. Primary endpoints were intraoperative blood loss and transfusion requirements. Secondary endpoints were perioperative fluid requirements, postoperative blood transfusions, complications, and mortality.

FINDINGS

137 patients received high-dose aprotinin (n=46), regular-dose aprotinin (n=43), or placebo (n=48). Intraoperative blood loss was significantly lower in the aprotinin-treated patients, with a reduction of 60% in the high-dose group and 44% in the regular-dose group, compared with the placebo group (p=0.03). Total amount of red blood cell (homologous and autologous) transfusion requirements was 37% lower in the high-dose group and 20% lower in the regular-dose group, than in the placebo group (p=0.02). Thromboembolic events occurred in two patients in the high-dose group, none in the regular-dose group, and in two patients in the placebo group (p=0.39). Mortality at 30 days did not differ between the three groups (6.5%, 4.7%, and 8.3%; p=0.79).

INTERPRETATION

Intraoperative use of aprotinin in adult patients undergoing orthotopic liver transplantation significantly reduces blood-transfusion requirements and should be routinely used in patients without contraindications.

Oral health of patients scheduled for elective abdominal aortic correction with prosthesis

OBJECTIVE

to evaluate the frequency of potential oral foci of infection in patients scheduled for elective abdominal aortic surgery.

DESIGN

prospective clinical study.

MATERIALS

oral health and dentures of 50 patients (33 males and 17 females, mean age 65 years) were examined before aortic surgery.

CHIEF OUTCOME MEASURES

radiographic and clinical examination with special emphasis on identifying acute and chronic oral and ontogenic conditions which may contribute to aortic prosthesis infection.

RESULTS

eighty-two per cent of the patients had some oral infection foci. The mean number of remaining teeth in the cohort was 9.3, and 21% of these were potential infectious foci (62% in the patients). Twenty-six per cent of the patients suffered from oral Candida infection. Seventy-four per cent of the patients had total or partial dentures, 45% of which were ill-fitting and needed repair.

CONCLUSIONS

oral infectious foci occur frequently in patients needing aortic surgery. Untreated foci may contribute to aortic prosthesis infection. Preoperative oral evaluation and elimination of intraoral infection is recommended for patients scheduled for abdominal aortic repair.

Factors associated with post-operative myocardial ischaemia in elderly patients undergoing major non-cardiac surgery

Forty patients (> 65 years) undergoing hip arthroplasty or peripheral vascular surgery both associated with high risk for post-operative myocardial ischaemia were randomized to receive either spinal or general anaesthesia. Ambulatory ECG recording (Holter) until the third post-operative morning, a daily 12-lead ECG and serum creatine kinase and troponine concentraItions were obtained. The number of ischaemic episodes, total duration of ischaemia and ischaemic minutes per hour were noted for each patient peri-operatively. Sixteen of the patients (40%) had post-operative myocardial ischaemia. An intra-operative increase in the plasma concentration of norepinephrine but not epinephrine was detected in the patients who later developed post-operative myocardial ischaemia. The increase in plasma norepinIephrine concentrations correlated with the decrease in core temperature. The type of anaesthesia had no effect on the incidence of myocardial ischaemia during or after surgery. Our results suggests that intra-operatively decreased core temperature and the increase in plasma concentration of norepinephrine probably caused peripheral vasoconstriction leading to latent cardiac dysfunction. These events should be avoided in the patients at risk of post-operative cardiac ischaemia.

Epileptiform electroencephalogram during mask induction of anesthesia with sevoflurane

BACKGROUND

Sevoflurane is suggested as a suitable anesthetic agent for mask induction in adults. The authors recently found that hyperventilation during sevoflurane-nitrous oxide-oxygen mask induction is associated with cardiovascular hyperdynamic response. We tested the hypothesis that the hyperdynamic response can be explained by electroencephalography (EEG) findings.

METHODS

Thirty women were randomly allocated to receive sevoflurane-nitrous oxygen-oxygen mask induction using a single-breath method, followed by either spontaneous breathing (n = 15) or controlled hyperventilation (n = 15) for 6 min. EEG was recorded. Blood pressure and heart rate were recorded at 1-min intervals.

RESULTS

Epileptiform EEG activity (spikes or polyspikes) was seen in all patients with controlled hyperventilation, and in seven patients with spontaneous breathing (P < 0.01). Jerking movements were seen in three patients with controlled hyperventilation. In the controlled hyperventilation group, heart rate increased 54% from baseline at 4 min after induction (P < 0.001). Mean arterial pressure increased 17% (P < 0.05), peaking at 3 min. In the spontaneous breathing group, heart rate showed no change, and mean arterial pressure decreased by 14% (P < 0.01) at 6 min. Heart rate and mean arterial pressure differed significantly between the groups from 2 min after beginning of the induction to the end of the trial. An increase in heart rate of more than 30% from baseline always was associated with epileptiform EEG activity.

CONCLUSIONS

Sevoflurane mask induction elicits epileptiform EEG patterns. These are associated with an increase in heart rate in patients with controlled hyperventilation and also during spontaneous breathing of sevoflurane.

Hepatic and splanchnic oxygenation during liver transplantation

OBJECTIVE

To evaluate hepatic and splanchnic oxygenation during liver transplantation.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

Ten adult patients undergoing liver transplantation.

INTERVENTIONS

Standardized surgery and anesthesia without venovenous bypass.

MEASUREMENTS AND MAIN RESULTS

Hepatic oxygenation was assessed by analyzing oxygen tension, oxygen saturation, and lactate concentration in hepatic venous blood. Splanchnic oxygenation was assessed by analyzing oxygen tension, oxygen saturation, and lactate concentration in portal venous blood and by gastric tonometry. Before reperfusion, the grafts were flushed with 1000 mL of acetated Ringer's solution and 400 mL of portal venous blood. The effluent blood from the graft was wasted and showed a mean pH of 6.86 and a lactate concentration of 9.4 mmol/L. Five minutes after portal reperfusion, most of the grafts produced lactate. Portal-hepatic venous P(CO2) difference ranged from 3 to 16 torr (0.4-2.1 kPa). By the time of restoration of the infrahepatic caval flow mean 24 mins later, eight of the grafts had stopped producing lactate. Mean hepatic venous oxygen tension was 47 torr (6.3 kPa), stabilizing to 41 torr (5.5 kPa) at the end of surgery. Acidosis resolved without pharmacologic interventions. Mean gastric mucosal pH was 7.29 during the anhepatic phase and 7.40 at the end of surgery. One of the patients developed hepatic arterial thrombosis intraoperatively. Her data were analyzed separately. Later, the other patients recovered with good liver function, whereas the patient with hepatic arterial thrombosis was successfully retransplanted.

CONCLUSIONS

The liver grafts received well-oxygenated portal venous blood during reperfusion, despite the low values of gastric mucosal pH immediately before reperfusion. Hepatic oxygenation became adequate soon after reperfusion. In the patient with hepatic arterial thrombosis, the recovery of hepatic oxygenation was impaired and lactic acidosis persisted.

Comparison of 125I- and (111)In-labeled monoclonal antibody BR96 for tumor targeting in combination with extracorporeal immunoadsorption

Extracorporeal whole blood immunoadsorption (ECIA) accelerates the clearance of radiolabeled monoclonal antibodies (mAbs) without significantly affecting tumor uptake by removing the excess of these mAbs from the blood, thus increasing tumor:normal tissue (T:N) ratios. The present study is focused on comparing the capacity of ECIA in tumor targeting with the same mAb (chiBR96-biotin) labeled with either (111)In or 125I. Forty-five Brown Norwegian rats with syngeneic rat colon carcinoma isografted both in liver and intramuscularly were used. chiBR96 is a highly tumor-specific mAb directed against the Lewis-type antigen. ECIA of whole blood was started 15 h after the injection of 125I- or (111)In-labeled BR96-biotin. The procedure lasted for 2 h and was repeated for (111)In-labeled BR96-biotin in a few rats after 3 or 24 h. ECIA reduced the whole body activity by the same magnitude (between 39% and 52%), irrespective of whether (111)In- or 125I-labeled chiBR96 was used. A similar observation was also made for the reduction in blood radioactivity after ECIA (79-94%). Time-activity curves during ECIA showed that the major reduction (approximately 85%) in blood radioactivity occurred during the first 45-60 min. Repeating the ECIA with (111)In-BR96 caused only an additional minimal reduction of blood activity, whereas a further reduction of whole body activity of 14-20% was achieved. The T:N uptake ratios were significantly enhanced immediately after ECIA with (111)In- or 125I-labeled chiBR96. Due to greater accumulation of (111)In-BR96 in tumors, a long-term improvement in T:N ratios was obtained after ECIA compared with 125I-labeled BR96. Our results therefore indicate that (111)In/(90Y)-labeled BR96-biotin could be more advantageous than 125I/131I for radioimmunotargeting/radioimmunotherapy in combination with ECIA due to better activity retention by the tumor.

Changes in heart rate variability in elderly patients undergoing major noncardiac surgery under spinal or general anesthesia

BACKGROUND AND OBJECTIVES

Heart rate variability (HRV), widely used as an indicator of activity of the autonomic nervous system, has been reported to decrease during and after both spinal and general anesthesia in patients without cardiovascular disease. We evaluated the changes in HRV bands in 40 patients with a high risk of ischemic heart disease.

METHODS

The patients were randomly assigned to receive either spinal (SA) or general anesthesia (GA) for elective total hip arthroplasty or peripheral vascular surgery. Anesthetic techniques and perioperative fluid administration were standardized. Holter monitoring was started preoperatively and continued until the third postoperative day. Three HRV frequency bands were analyzed.

RESULTS

A significant decrease was seen in very low frequency (VLF) and low frequency (LF) bands during GA but not during SA. Also the LF/high frequency (HF) ratio decreased during GA but not during SA. A decrease in all HRV frequency bands was seen after both types of anesthesia. None of the frequency bands returned back to the preoperative level during the 3-day trial. Postoperatively circadian variation was found only in the VLF band after SA.

CONCLUSIONS

The sympathovagal balance (LF/HF) is more stable during SA than during GA in patients with a high risk of ischemic heart disease. The postoperative decrease in HRV bands, however, is independent of the anesthetic technique.

QT dispersion after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) causes a stress response with increased concentrations of plasma catecholamines and serious cardiac arrhythmias. Increased QT dispersion has been shown to predispose to cardiac arrhythmias. In SAH patients, QT dispersion has not been studied previously. QT dispersion was analyzed in 26 patients with SAH and in 16 patients (control group) scheduled for ligation of a nonruptured cerebral aneurysm. In 15 patients with SAH, the plasma concentrations of catecholamines were analyzed, and an 18-hour continuous electrocardiogram (ECG) recording was obtained. In the other 11 patients, electrocardiography was repeated daily for up to 9 days for analysis of QT dispersion. The median (25th and 75th percentiles) QT dispersion in all SAH patients was 78 milliseconds (50 and 109 milliseconds, respectively), and in control patients, it was 25 milliseconds (15 and 33 milliseconds, respectively) (P < .001). There was a positive correlation with QT dispersion and the plasma concentration of DHPG, a metabolite of norepinephrine (P < .05). All patients had episodes of cardiac arrhythmia during the 18-hour recording period. In conclusion, increased QT dispersion is a common finding after SAH and may be a result of high plasma concentrations of catecholamines in these patients.

Induction characteristics of thiopentone/suxamethonium, propofol/alfentanil or halothane alone in children aged 1-3 years

The aim of this study was to compare the effect of three different induction techniques, with or without neuromuscular block, on tracheal intubation, haemodynamic responses and cardiac rhythm. Ninety children, aged 1-3 years, undergoing day-case adenoidectomy were randomly allocated to three groups: group TS received thiopentone 5 mg kg-1 and suxamethonium 1.5 mg kg-1, group H 5 Vol.% halothane and group PA alfentanil 10 micrograms kg-1 and propofol 3 mg kg-1 for induction of anaesthesia. No anti-cholinergics were used. Holter-monitoring of the heart rate and rhythm was started at least 15 min before induction of anaesthesia and continued until 3 min after intubation. Tracheal intubation was performed by an anaesthetist blinded to the induction method and judged as excellent, moderate or poor according to ease of laryngoscopy, position of vocal cords and incidence of coughing after intubation. Tracheal intubation was successful at the first attempt in all children in groups TS and H and but only in 80% in group PA (P = 0.001). Intubating conditions were excellent in 22 (73%), 22 (73%) and one (3%) of the patients in groups TS, H and PA, respectively (P = 0.001). Cardiac dysrhythmias (supraventricular extrasystole or junctional rhythm) occurred in two (7%) patients in groups PA and H each (NS). Bradycardia occurred in 0 (0%), four (14%) and six (21%) children in groups TS, H and PA, respectively (P = 0.007 PA vs. TS, P = 0.03 H vs. TS). In conclusion, induction of anaesthesia with propofol 3 mg kg-1 and alfentanil 10 micrograms kg-1 without neuromuscular block did not provide acceptable intubating conditions in children 1-3 years, although it preserved arterial pressure better than thiopentone/suxamethonium or halothane. Cardiac dysrhythmias were few regardless of the induction method.

Transient hyperdynamic response associated with controlled hypocapneic hyperventilation during sevoflurane-nitrous oxide mask induction in adults

We assessed hemodynamic variables during sevoflurane face mask anesthetic induction in female ASA physical status I or II patients. Anesthesia was induced with a single-breath inhalation method with 8% sevoflurane in 50% nitrous oxide in oxygen. Thirty patients were randomized either to breathe spontaneously (SB group, n = 15) or to receive controlled ventilation (CV group, n = 15) for 6 min after the loss of consciousness. Noninvasive blood pressure and heart rate (HR) were recorded at 1-min intervals. Mean +/- SD HR increased from 83+/-18 to 112+/-24 bpm at 4 min in the CV group (P < 0.001 between groups and within group compared with baseline). Mean arterial pressure increased from 97+/-9 to 106+/-26 mm Hg at 4 min in the CV group, which was significantly higher than that in the SB group (P < 0.01). In the SB group, mean arterial pressure decreased significantly, from 96+/-8 to 78+/-13 mmHg, at 6 min (P < 0.001), and HR remained unchanged. Therefore, hyperventilation should be avoided during the induction of sevoflurane anesthesia via a mask.

IMPLICATIONS

In this randomized, prospective study, we found that controlled hypocapneic hyperventilation delivered manually during sevoflurane/ N2O/O2 mask induction was associated with a significant transient hyperdynamic response. This kind of hemodynamic arousal can be detrimental to many patients and can be avoided by conducting sevoflurane mask induction with unassisted spontaneous breathing.

Sevoflurane requirement for laparoscopic tubal ligation: an electroencephalographic bispectral study

It has been shown in healthy volunteers that a concentration of volatile anaesthetic lower than 1 minimum alveolar concentration provides unconsciousness. We tested the hypothesis that, using the electroencephalogram bispectral index, less than 1 minimum alveolar concentration of sevoflurane can produce unconsciousness in patients. Anaesthesia was induced and maintained with sevoflurane in N2O and O2 (33%) in 32 ASA I-II women undergoing laparoscopic tubal ligation. For the first patient, the sevoflurane concentration was adjusted to 1 minimum alveolar concentration with an end-tidal concentration of 0.7%. The electroencephalogram bispectral index values were used to determine the concentration to be used for the next patient. The ED50 (effective dose) measured using end tidal concentrations of sevoflurane for laparoscopic tubal ligation in a 40-year-old patient was 0.70% (CI 95%: 0.63-0.77) and ED95 0.83% (CI 95%: 0.75-0.90). None of the patients had any operation-associated recall. It is concluded that the sevoflurane concentration needed for laparoscopic tubal ligation is not lower than 1 minimum alveolar concentration.

Time course of the inflammatory response to histamine and allergen skin prick test in guinea-pigs

Plasma exudation and vasodilatation are key microvascular features of acute inflammation. Exudation and vasodilatation responses in the weal area after skin prick testing with histamine are essentially completed within 30 min. There is evidence to suggest that vasodilatation lasts considerably longer after provocation with allergen, but there is no information on the duration of plasma exudation. The purpose of this study was to measure the time course of the microvascular inflammatory response in the skin after histamine and allergen provocation. Skin prick tests were performed with histamine, allergen (ovalbumin) or saline (control) on guinea-pigs which were shaved on their backs. Radioactive 113mIn was used to label transferrin as a plasma tracer. Radioactivity was recorded from the superficial part of the skin by external detection of conversion electrons from the decay of 113mIn. The increase in count rate, corresponding to tracer accumulation by vasodilatation and/or plasma exudation, was used as a measure of the microvascular inflammatory response to skin prick test. The microvascular response was studied immediately and up to 30 min after provocation. The largest response to histamine and allergen occurred immediately after provocation. The exudative response then gradually declined to be absent after 25-30 min. Skin prick test with saline resulted in a small response of shorter duration. We conclude that the microvascular reaction to histamine as well as allergen provocation in guinea-pig skin has a rapid onset and a duration of approximately 30 min.

Effect of temperature of insufflated CO2 during and after prolonged laparoscopic surgery

BACKGROUND

Pneumoperitoneum with room temperature carbon dioxide (CO2) has been shown to decrease core temperature and urine output.

METHODS

The effect of 37 degrees C (warm) and room temperature (cool) CO2 pneumoperitoneum on core temperature, urine output, and central hemodynamics was compared in 26 randomized patients undergoing prolonged laparoscopic surgery (>90 min).

RESULTS

The core temperature (p < 0.05) and cardiac index (p < 0.05) were significantly higher after warm than after cool pneumoperitoneum. Urine output was significantly higher during warm (2.3 +/- 1.6 ml/kg/h) than during cool (0.9 +/- 0.7 ml/kg/h) insufflation (p < 0. 05). Two of 13 patients with warm and 11 of 13 patients with cool pneumoperitoneum needed mannitol to maintain adequate diuresis (p < 0.05).

CONCLUSIONS

Warm insufflation probably causes a local vasodilation in the kidneys and may be beneficial to patients with borderline renal function.

Effect of oxygen on pulmonary hemodynamics and incidence of atrial fibrillation after noncardiac thoracotomy

OBJECTIVE

The mechanism of postthoracotomy atrial fibrillation (AF) could be related to right ventricular (RV) strain. The effect of oxygen on the occurrence of postoperative AF and on RV function was studied.

DESIGN

A prospective, randomized study.

SETTING

A university hospital.

PARTICIPANTS

Twenty-four noncardiac thoracotomy patients.

INTERVENTIONS

At the end of the postoperative anesthesia care unit period, the patients were randomly allocated to receive 35% oxygen until either the third (P = prolonged group) or the first postoperative morning (S = short group).

MEASUREMENTS AND MAIN RESULTS

Measurement of hemodynamic variables using a thermodilution pulmonary artery catheter, oxygenation, concentration of plasma atrial natriuretic peptide (ANP) and Holter monitoring were started preoperatively and continued for the 3 postoperative days (PODs). Systolic RV pressure (systolic RVP) and pulmonary vascular resistance (PVR) increased postoperatively only in group S. Major changes in RV performance were not seen with echocardiography or the thermodilution method in any patient. Silent episodes of AF occurred in three patients (25%) in group P and in one patient (8%) in group S (not significant [NS]) without deviations in plasma ANP concentration. On each of the 3 PODs, all patients were exposed to 60% oxygen for 15 minutes. Systolic RVP decreased significantly during the exposure to 60% oxygen only in group S, but not in patients developing AF. Predictive factors for AF were a high preoperative PVR, intraoperative bleeding necessitating volume loading, and elevated systolic RVP immediately after thoracotomy.

CONCLUSION

Short episodes of AF occurred irrespective of the length of oxygen therapy. Occurrence of AF could not be explained by changes in RV function.

Comparison of intrathecal morphine and continuous femoral 3-in-1 block for pain after major knee surgery under spinal anaesthesia

Major knee surgery is associated with moderate or severe post-operative pain. Intrathecal morphine and continuous femoral 3-in-1 block were compared prospectively in 40 patients for pain after major knee surgery under spinal anaesthesia, with 4 mL isobaric 0.5% bupivacaine. In a random order, 20 patients received preservative free morphine 0.3 mg mixed with spinal bupivacaine. In 20 patients, following spinal anaesthesia with only bupivacaine, femoral 3-in-1 block was performed post-operatively with 0.5% bupivacaine 2 mg kg-1. The block was continued via a catheter with 0.25% bupivacaine 0.1 mL h-1 kg-1 until the next morning (24 h after induction of spinal anaesthesia). Intramuscular oxycodone was given as a rescue analgesic in all patients. Two patients from the femoral group were excluded due to technical failure. Three patients in the morphine group and one patient in the femoral group did not need any additional oxycodone. In the morphine group on average 2.8 (range 0-7) and in the femoral group 3.2 (0-5) additional doses of oxycodone were needed during the 24 h observation period. The mean pain scores were significantly lower in the morphine group at 9 and 12 h into the 24-h trial. Itching was seen only in the morphine group (40% of the patients). Other side effects were similar in the two groups. All patients were satisfied with their pain therapy. Both intrathecal morphine and femoral 3-in-1 block alone were insufficient for the treatment of severe pain after major knee surgery.

Effects of esmolol on haemodynamic response to CO2 pneumoperitoneum for laparoscopic surgery

BACKGROUND

Carbon dioxide (CO2) pneumoperitoneum for laparoscopic surgery increases arterial pressures, systemic vascular resistance and heart rate and decreases urine output.

METHODS

In this double-blind randomized study esmolol, an ultrashort-acting beta1-adrenoceptor antagonist was compared with physiological saline (control) in 28 patients undergoing laparoscopic surgery in standardized 1 MAC isoflurane anaesthesia. Alfentanil infusion was used to prevent the increase of mean arterial pressure more than 25% from baseline.

RESULTS

Esmolol effectively prevented the pressor response to induction and maintenance of CO2 pneumoperitoneum. Significantly (P<0.001) less alfentanil was needed in the esmolol group than in the control group. Urine output was higher (P<0.05) and plasma renin activity (P<0.01) and urine N-acetyl-beta-D-glucosaminidase levels lower in the esmolol group when compared with the control group.

CONCLUSIONS

Esmolol blunts the pressor response to induction and maintenance of pneumoperitoneum and may protect against renal ischaemia during pneumoperitoneum.

Detrimental effect of dietary sodium and beneficial effect of dietary magnesium on glomerular changes in cyclosporin-A-treated spontaneously hypertensive rats

BACKGROUND

Cyclosporin A (CsA) causes renal magnesium wasting, hypertension, and occasionally irreversible renal damage. We examined the effect of dietary sodium and magnesium on renal histology in spontaneously hypertensive rats (SHR) receiving CsA.

METHODS

Forty-six 8-week-old SHR were divided into six groups and given different dietary levels of sodium (low 0.3%, high 2.6%) and magnesium (low 0.2%, high 0.6%). Low-dose CsA (5 mg/kg/d) was given subcutaneously for 6 weeks in four groups. Systolic blood pressure, serum creatinine, degree of proteinuria, and renal tissue CsA and calcium concentrations were determined. Kidney wet weight to total body-weight ratio was calculated as an index of renal hypertrophy. Renal histological alterations were scored according to glomerular changes: 100 glomeruli were assigned for severity of change a score from 0 to 3. The number of affected glomeruli was multiplied by the damage score to obtain a damage index.

RESULTS

In the CsA-treated high-sodium diet group systolic blood pressure and glomerular damage index were increased, and renal hypertrophy was the most common. These changes were prevented by oral magnesium supplementation. The glomerular damage index correlated positively with increases in systolic blood pressure, serum creatinine, proteinuria, and renal calcium concentration.

CONCLUSIONS

Dietary sodium enhanced CsA-induced functional and morphological renal changes in SHR and aggravated hypertensive renal arteriolar and glomerular lesions. Dietary magnesium supplementation protected against the deleterious effects of sodium and CsA.

Outcome of infrainguinal bypass surgery for critical leg ischaemia in patients with chronic renal failure

OBJECTIVE

To determine whether infrainguinal bypass surgery is worthwhile in patients with critical limb ischaemia (CLI) and chronic renal failure.

DESIGN

Longitudinal observational study.

MATERIALS AND METHODS

Twenty-two patients with moderate renal failure indicated by serum creatinine level above 150 mumol/l, 10 patients with end-stage renal disease requiring dialysis, and three patients with functioning kidney transplant, underwent 39 bypass procedures for critical limb ischaemia.

RESULTS

Six femoropopliteal, 14 femorocrural and 19 femoropedal bypasses were performed. The immediate, 1-month, and 1-year primary patency rates were 97%, 84% and 70%, respectively. The limb salvage was 93% at 1-month and 72% at 1-year follow-up. One-year patency and leg salvage rates were 81% and 79% in non-dialysis patients, and 47% and 37% in dialysis patients. At 1-year follow-up, 55% of surviving patients had salvaged limbs. None of the patients in dialysis was alive with salvaged legs 4 months after revascularisation. Among preoperative risk factors, only serum creatinine showed a statistical significance in predicting leg salvage and survival.

CONCLUSIONS

As the outcome of patients on dialysis is very poor after infrainguinal bypass grafting, revascularisation is seldom indicated. On the contrary, leg salvage can achieve good results in patients not requiring dialysis.

A comparison of gasless mechanical and conventional carbon dioxide pneumoperitoneum methods for laparoscopic cholecystectomy

Carbon dioxide (CO2) insufflation with increased intraabdominal pressure (IAP) has adverse hemodynamic, pulmonary, and renal effects. To avoid these problems, an abdominal wall lift method with a retractor was used to provide the surgical view without CO2 insufflation. Twenty-six patients undergoing elective laparoscopic cholecystectomy were randomly allocated to either the gasless, retractor group, or conventional CO2 pneumoperitoneum group (CPP). Hemodynamic data, ventilatory variables, urine output, urine oxygen tension, and blood samples for determining stress hormones were collected throughout the perioperative period. Patients in the retractor group had lower mean arterial pressure, heart rate, and central venous pressure (P < 0.001). They also had higher pulmonary dynamic compliance and needed a lower minute volume of ventilation to achieve normocarbia (P < 0.001). Urine output and oxygen tension in urine were higher (P < 0.05) with the retractor method than with CPP. Increase in plasma renin activity (P < 0.05) and decrease in core temperature (P < 0.001) were smaller with the gasless method than with CPP. The gasless method for laparoscopic cholecystectomy might be beneficial, especially in patients with compromised cardiorespiratory or renal function.

IMPLICATIONS

Totally gasless laparoscopic cholecystectomy was compared with conventional pressure pneumoperitoneum with CO2 insufflation. The gasless method resulted in more stable hemodynamics and pulmonary function, as well as higher urine, output than conventional pressure pneumoperitoneum. No changes in renal oxygenation was seen with the gasless method, compared with conventional pressure pneumoperitoneum.