Influence of hydroxyethyl starch 130/0.4 versus ringer lactate on renal function during acute normovolemic haemodilution in combination with controlled hypotension

The risks associated with banked homologous blood products are well known. Several techniques for management of surgical patients without homologous blood transfusion are available. Controlled hypotension and acute normovolemic haemodilution [ANH] have been proven effective in decreasing operative blood loss and the need for transfusion of allogenic blood. The combined reduction of oxygen carrying capacity and perfusion pressure during combination of ANH and controlled hypotension raises the concerns of hypoperfusion and ischaemic injury to the kidney. Forty patients undergoing major abdominal surgery were allocated to receive controlled hypotension induced by Na nitroprusside [mean arterial pressure 50 mm Hg] and acute normovolemic haemodilution [post ANH haematocrite 29%]. ANH was established by withdrawing venous blood into standard blood bags and replacing it by HES 130/0.4 [Group I] or RL [group II]. The shed blood was reinfused at the end of surgery. Subclinical alteration in renal integrity detected by sensitive markers of tubular damage has been reported in the absence of overt change in creatinine serum concentration and creatinine clearance in both groups. These markers have returned to normal values after 24 hours. Sensitive markers of kidney dysfunction have increased in both groups indicating moderate alterations in renal integrity during combination of ANH and controlled hypotension. Both volume replacement regimens did not differ with regard to kidney integrity

Study of the preconditioning effect of sevoflurane against acute ischemia reperfusion injury of the lower limb skeletal muscles after tourniquet deflation

Preconditioning [PC] is a process where cells or tissues exposed to a sublethal stimulus are transiently protected from a subsequent normal lethal stress. Many forms of preconditioning have been investigated, such as ischemic, thermal, pharmacologic, or gas inhalation. The present study aimed to study the preconditioning effect of sevoflurane as a prophylaxis against ischemia reperfusion injury of the lower limb skeletal muscles after tourniquet deflation. The study was carried out on 40 adult patients. The patients were randomly assigned into two equal groups, each one including 20 patients. Group I: received sevoflurane anesthesia. Group II: received spinal anesthesia using heavy bupivacaine 15 mg. Biochemical parameters of muscle injury including serum CPK, AST, K, Ca, ABGs, lactic acid, IL-6 and TNF[alpha] were compared between both groups before induction of anaesthesia, and 5 min after deflation of the tourniquet. Both groups showed an increase in CPK and AST levels 5 minutes after tourniquet deflation but the increase was significantly higher in group II; CPK was 61.1+13.6 IU/L in the sevoflurane group versus 76.2+11.4 IU/L in the control[spinal] group. Also AST was 28.4+6.9 IU/L in the sevoflurane group versus 55.5+6.3IU/L in the control group. Both groups developed increase in serum K 5 min. after tourniquet deflation and the increase was significantly higher in the control group; serum K was 4.4+0.71 meq/L in the sevoflurane group vs. 5.1+0.4 meq/L in the control group. Both groups showed an increase in serum Ca level 5 minutes after tourniquet deflation but there was no significant difference between them. There were no significant differences in PaO2 or arterial pH between both groups, however the control group showed a significantly higher PaCO2 and a significantly lower arterial HCO3 - values than in the sevoflurane group 5 min. after tourniquet deflation. Serum lactic acid, IL-6 and TNF[-alpha] significantly increased in both groups 5 min. after tourniquet deflation but the rate of increase was higher in the control group; serum lactic acid was 1.30 + 0.25 mg/dl in the sevoflurane group vs. 1.98 + 0.27 mg/dl in the control group, IL-6 was 50.4 + 12.6 pg/ml in the sevoflurane group vs. 66.7 + 9.9pg/ml in the control group, and TNF[-alpha] was 15.6 + 6.4 pg/ml in the sevoflurane group vs. 28.4 + 5.8 pg/ml in the control group 5 min. after tourniquet deflation. In conclusion, the findings of the study has shown that sevoflurane has a preconditioning effect on human skeletal muscles as evidenced by a lower biochemical parameters of muscle injury

Assessment of intraoperative use of ringer acetate in patients with liver cirrhosis

In this study, Acetated Ringer [AR] and Lactated Ringer [LR] were used as intraoperative infusions in patients with liver cirrhosis during elective surgery under general anaesthesia Their effect on acid- base balance, serum pyruvate, serum lactate, ketone bodies concentration, liver function, blood glucose level and haemodynamic parameters were evaluated intra and postoperatively. Thirty patients [grade A, Child-Pugh classification] were divided into two groups according to the type of the infused solution; LR or AR. Postoperative Pyruvate level in AR [1 21 +/- 0 39 mg/dl] was significantly higher than in LR group [0.47 +/- 0.11 mg/dl]. However, the level of lactate in LR group postoperatively [16.80 +/- 1.61 mg/dl] increased significantly in comparison to that in AR group [8.87 +/- 0.92 mg/dl]. The ketone bodies concentration was significantly higher in AR group [2.33 +/- 0.42 mg/dl] than in LR group [0.40 +/- 0.20 mg/dl]. There was no significant changes in pH, HCO3, base excess, liver function, blood glucose level and haemodynamic parameters in both groups either tntraoperatively or at the end of the infusion These results suggest that AR may be more beneficial as an intraoperative fluid than LR. Acetated ringer decreased the metabolic load to the liver and improved hepatic energy status in patients with liver dysfunction

Effects of propofol total intravenous anesthesia versus sevoflurane inhalational anesthesia on pulmonary shunt fraction and haemodynamics during one lung ventilation in thoracic surgery

One-lung ventilation [OLV] is required for several thoracic operations. The effects of anesthesia and one-lung ventilation on arterial oxygenation are complex and not fully understood; adequate arterial oxygen is not achieved in some patients despite an accurately placed endobronchial tube and high inspired oxygen. The present study compared the effect of both total intravenous anesthesia using propofol infusion and inhalational anesthesia using sevoflurane on pulmonary shunt fraction and haemodynamic variables in patients requiring OLV during thoracic surgery. Twenty patients were studied, aged 20-65 years ASA physical status, II, and III; they were scheduled for lobectomy with OLV, and were randomly assigned into two groups. Group I: Patients were anesthetized using I.V. anesthesia using propofol. Group II: Patients were anesthetized with inhalation anesthesia using sevoflurane. Blood gas values [PaO2, PaCO2, SpaO2], mixed venous blood samples and haemodynamic data [HR, MAP, CVP, PAP and PCWP] were obtained. Four sets of measurements were taken: after 15 min. of stable total lung ventilation [TLV], after 15 min. of stable OLV in supine position [OLVs], after 15 min. of stable OLV in lateral position [OLVL] and after opening thorax [OLVo]. Shunt fraction [Qs/Qt] was calculated using standard formula Qs/Qt = [CcO2-CaO2]/[CcO2-CvO2]. Also, CI, SVRI, and PVRI were calculated. There was significant increase in PaCO2 values in both groups but no significant difference was found between the two groups. Both groups showed significant decrease in PvO2 throughout the entire four-step sequences and no significance was found between the two groups. Average shunt during OLVs increased by 11.02% and 5.6% from TLV and during OLVL by 14% and 10.29% for propofol and sevoflurane respectively; this increase showed statistically significant value in both groups. Institution of OLVs was associated with a significant decrease in CI in each group and there was no significance between groups; turning the patient to lateral position together with opening chest was associated with significant increase in CI and these results did not show any significance between groups. Significant reduction in SVRI was observed after initiation of OLVs in propofol group while SVRI increased in sevoflurane group; these changes were statistically insignificant between the two groups. Turning the patient to lateral position together with opening the chest were associated with significant increase in SVRI in each group,but it was significantly higher in the propofol group. PVRI decreased after turning the patient to lateral position in propofol group while PVRI increased in sevoflurane group. In conclusion: both sevoflurane and propofol administration causes an increase in shunt fraction. PvO2, PaO2, PaCO2, CI did not differ between both groups. Both sevoflurane and propofol are considered as good drugs for thoracic operations but sevoflurane appears to give more cardiovascular stability