Effects of thoracic epidural anesthesia on pulmonary venous admixture and oxygenation with isoflurane or propofol anesthesia during one lung ventilation

Thoracic epidural anesthesia [TEA] with local anesthetics during OLV is increasingly being combined with general anesthesia [GA] in our clinical practice for thoracic surgery. A combination of TEA with GA might maximize the benefits of each form of anesthesia. Furthermore, epidural anesthesia and postoperative epidural analgesia may improve outcome in high-risk patients. The present study was designed to compare the effects of thoracic epidural anesthesia on oxygenation and pulmonary venous admixture [Qs/Qt], when combined with isoflurane or propofol anesthesia, during one lung ventilation and to compare also between the effects of propofol with isoflurane on oxygenation and pulmonary venous admixture [Qs/Qt], during one lung ventilation. This study was carried out on 60 patients, [ASA classification I-II-III] in Tanta University Hospitals, scheduled for thoracotomies for pulmonary resections in the lateral decubitus position and one-lung ventilation. The patients were randomized into one of four groups, 15 patients in each group: Group I: propofol group [TIVA group], Group II: propofol combined with thoracic epidural anesthesia [TIVA-TEA group], Group III: isoflurane group [ISO group] and Group IV: isoflurane combined with thoracic epidural. The trachea was intubated with a doublelumen tube and its position was confirmed with auscultation. Anesthesia was maintained with propofol at continuous infusion in [Group I and Group II], and with isoflurane in [Group III and Group IV] and with increments of fentanyl and vecuronium. PaO[2], PaCO[2], SaO[2], PvO[2], SvO[2] and Hb, as well as the hemodynamic variables [HR and MAP] were measured. A right atrial blood sample was used to calculate the pulmonary venous admixture [Qs/Qt]. In epidural groups [Group II and Group IV] a 10-ml bolus of a solution of bupivacaine 0.1%+ 0.1 mg/ml morphine in saline was administered at least 30 min before the induction, followed by a 7 ml/h infusion of the same solution during the operation. In the other two groups [Group III and Group IV], no medication was applied via the epidural catheter in the preoperative and the intraoperative period. After preoxygenation, anesthesia was induced with fentanyl 3 microg/kg and propofol 2 mg/kg; tracheal intubation was facilitated with vecuronium 0.1 mg/kg. As regards PaO[2], it was significantly higher in Group I and Group II [propofol groups] than Group III and Group IV [isoflurane], in contrary, no significant effect of TEA [between Group I and Group II] nor between [Group III and Group IV] on PaO[2]. However; PaO[2] significantly decreased during OLV in all groups. As regards Qs/Qt, it was significantly lower in Group I and Group II [propofol groups] than Group III and Group IV [isoflurane], in contrary, no significant effect of TEA [between GI and GII] nor between [GIII and GIV] on Qs/Qt. However; Qs/ Qt significantly increased during OLV in all groups. The administration of thoracic epidural anesthesia, either combined with propofol or isoflurane, was not associated with a relevant impairment of oxygenation during OLV. Therefore Pre-emptive analgesia via an epidural thoracic catheter can be used safely as a standard in lung surgery, decreasing the anesthesia requirements when combined with GA, maximizing the benefits of each form of anesthesia and improving the outcome in patients with cardiopulmonary diseases, hence it was found that it has no effect on oxygenation during OLV, and it is associated with stable hemodynamics

influence of general anesthesia when combined with epidural anesthesia in postoperative delirium in elderly patients undergoing hip replacement surgery

Cognitive impairment [e.g., delirium confusion] is a significant problem in elderly patients during the early postoperative period. Postoperative delirium, a transient mental dysfunction, can result in Increased morbidity, delayed functional recovery and prolonged hospital stay in the elderly. The aim of this study is to determine the effect of epidural anesthesia when combined with general anesthesia on the incidence as well as the recovery of delirium in elderly patients undergoing hip replacement surgery. The present study was carried out on sixty adult patients [ASA I-I1I] of both sex scheduled for hip replacement surgery. Patients were randomly allocated to one of two groups to receive either general anesthesia [GA group, n =30] or GA plus epidural anesthesia with 0.75% ropivacaine [GA-EDA group, n = 30]. All patients were tested for cognitive dysfunction [Delirium] using the Confusion Assessment Method [CAM] score preoperatively and for 24 hr postoperatively. This study showed a significant incidence of +ve CAM score [36.7% and 26.7%] in the GA group and GA- EDA groups respectively at 1hr postoperatively when compared with the preoperative baseline values. From the 2[nd] hr postoperatively, there were continuous reduction in the +ve CAM score patients throughout the study period. When comparing the two studied groups, there were no significant difference in the incidence of +ve CAM score throughout the study period. Epidural anesthesia in combination with general anesthesia does not affect the incidence as well as the recovery pattern of delirium in elderly patients undergoing hip replacement surgery

Comparison of colloid versus crystalloid preload for prevention of hypotension during spinal anesthesia for elective cesarean section in women with positive supine stress test

If parturient prone to develop caval compression in the supine position were identified before delivery; this might be a method of predicting hypotension during cesarean section under spinal anesthesia. Colloid preloading is thought to be superior to crystalloid in reducing the risk for spinal anesthetic induced hypotension. It is postulated that parturients preoperalively susceptible to the supine position would benefit the most from colloid preloading. The aim of this study is to compare colloid versus crystalloid preload for prevenilon of hypotension during spinal anesthesia for elective cesarean section in women with positive supine stress test [SST]. Forty healthy women, with term singleton normal pregnandes presenling for elective cesarean section under spinal anesthesia were included in the study. All patients were positivefir supine stress test [SST], they were divided into 2 equal groups [20 palients each], crystalloid preload group [group I] and colloid preload group [group II]. IViaternal hypotension, nausea, vomiting or dizziness and ephedrine requirements were recorded during the study. Induction-to-uterotomy interval, uterotomy-to-delivery interval and inlraoperative blood loss, were also recorded. Moreover, Apgar score and umbilical artery add-base status at delivery were measured. Our results showed that in patients received crystalloid preload [group I] the frequendes of occurrence of decreased systolic blood pressure below 100 mmHg or 20% from baseline, occurrence of vomiting, nausea or dizziness were 14[70%], 7[35%], 9[45%], and 7[35%], respectively, while, in palients received colloid preload [group II] were 6[30%], 1[5%], 2[10%], and 1[5%], respectively. So, patients received crystalloid preload showed a higher frequency of hypotension, vomiting, nausea and dizziness compared to colloid group [P<0.05], and also a greater need for ephedrine, mean[+SD] was 21[11.4] in group I compared to 7.25.3]mg in group II[P<0.05]. Pregnant women with a positive preoperative supine stress test constitute a subset at increased risk for clinically significant hypotension during cesarean delivery under spinal anesthesia. These women seem more likely to benefit from prophylaclic colloid solution preload

Effects of sevoflurane and isoflurane on coagulation system a comparative study

Several studies of the effects of inhalational anesthetic agents on platelet function have been reported since Ueda demonstrated in 1971 that clinical concentrations of halothane inhibited ADP-induced platelet aggregation. Sevoflurane in particular has recently been the subject of several investigations; however, the results remain contradictory. Platelets play an important role in hemostasis during and after surgery. Among multiple factors, interactions of drugs used in anesthesia with platelet function have been implicated to aggravate the risk of perioperative bleeding. In this study, the aim was to assess the effects of sevoflurane and isoflurane on the coagulation system. Patients were randomly divided into two groups [30 patients each]: isoflurane group [group I] and sevoflurane group [group S] according to the inhalational anesthetic used for maintenance of anesthesia. Blood samples were withdrawn before induction, 1 hour after induction and 1 hour postoperatively to measure red blood cells count, hemoglobin level, platelets count, bleeding time, prothrombin time and activity, activated partial thromboplastin time, pH, body temperature and platelet aggregation tests. The results of this study showed that red blood cells count, hemoglobin level, blood pH values and vital signs measurements were insignificantly changed during the predetermined times of measurements. Sevoflurane had a significant inhibitory effect on intraoperative platelet aggregation. Also, it had a residual suppressive effect 1 hour postoperatively, whereas it had no significant effect on other coagulation parameters including platelet count, bleeding time, prothrombin time and activity and activated partial thromboplastin time. As regards isoflurane, it had no significant effect neither on platelet aggregation nor other coagulation parameters during the intraoperative and postoperative periods. The conclusion of this study is that sevoflurane has a significant inhibitory effect on intraoperative platelet aggregation, whereas isoflurane has no effect. There is also a residual suppressive effect 1 hour postoperatively with sevoflurane. Therefore, in patients at increased risk of intraoperative and postoperative bleeding, isoflurane may be preferred as an inhalational agent for maintenance of general anesthesia.