effect of perfusion pressure during cardiopulmonary bypass on gastric mucosal pH

The objective of this prospective randomized study was to investigate the effect of high and low perfusion pressure during cardiopulmonary bypass [CPB] on the gastric mucosal pH [pHim]. The study was carried out on 30 patients scheduled for elective valve replacement surgery and allocated randomly into one of two groups: group I [n=14] managed by perfusion pressure of 70-90 mmHg during CPB and group II [n= 16] managed by perfusion pressure < 60 mmHg during CPB. All patients were subjected to the same method of anesthesia, monitoring, anticoagulation and myocardial protection. ABG, PCO[2] [R-a], pHim were recorded before, during, at the end of and one hour after CPB. The results of this study revealed that in contrast to high perfusion pressure low perfusion pressure was associated with significant gastric mucosal acidosis during and after CPB. So we can concluded that the use of perfusion pressure >/= 70 mmHg can prevent or attenuate gastric mucosal acidosis during open cardiac surgery

Effect of spinal versus general anesthesia on the postoperative cognitive function in elderly patients

The objective of this prospective randomized study was to compare the effect of general and spinal anesthesia on the cognitive function in elderly patients. Forty-two patients [male: female 18 : 24] between the ages of 60 and 73 yr old undergoing knee arthroplasty were randomly allocated into one of two groups: group I [n=20] received general anesthesia, and all of them receive the same anesthetic technique, and group II [n=22] received spinal anesthesia. Initially, all patients were assessed by Blessed dementia scale and Hamilton Depression Rating Scale. A battery of neuropsychological measures including Circle Connection, Benton visual Retention Memory, Digit Span and Controlled Word Association, were carried out before surgery and again one and seven days after surgery, then 3 months later. Analysis of data revealed that the two groups were similar in terms of demographic data, baseline cognitive function scores, duration of surgery and intraoperative mean arterial blood pressure [MAP], oxygen saturation [SpO[2]%], and the amount of fluid needed. The results indicated that there were an early postoperative cognitive dysfunction [POCD] at one day after surgery in both study groups. One week later the cognitive function returned to baseline scores. At the 3rd month follow up, the cognitive measures were normal and even showed a statistically non significant improvement in both groups. We can conclude that PO CD after general or regional anesthesia was transient and there were no POCD after 3 months in elderly patients undergoing knee arthroplasty under general or regional anesthesia

Delta gap changes should guide therapy in different cases of metabolic acidosis

Metabolic acidosis is associated with serious morbidities and mortality. Its diagnosis is difficult because it is frequently associated with mixed acid-base disorders and its clinical manifestations are often non specific or subclinical, which means that its diagnosis is made from laboratory and other diagnostic tests. The aim of this study was to use the delta gap for accurate interpretation of normal anion gap [AG] acidosis, high AG acidosis and if there was a coexisted metabolic disorders associated with the metabolic acidosis. Such diagnosis is beneficial in the management of each type of these metabolic disorders. Forty hundred and seventy nine measurements of acid-base changes were drawn from 479 ICU critically ill patients and patients with metabolic acidosis were selected. They were divided according to the aetiology of their acidotic condition into a renal failure group [n = 23] and a sepsis group [n= 26]. Arterial blood gases [ABG] were analyzed and the anion gap [AG] was calculated by arterial blood gas analyzer. In the renal failure group the incidence of metabolic acidosis was: normal AG acidosis 9%, mixed [normal and high] AG acidosis 48% and high AG acidosis 43%, but there was no associated metabolic alkalosis. In sepsis group, 23% of the patients had normal AG acidosis, 42% of patients had mixed [normal and high] AG acidosis, 12% of patients had high AG acidosis and the remaining cases [23%] had an associated metabolic alkalosis. In conclusion, AG is important for differential diagnosis between normal and high AG metabolic acidosis. Delta gap is an important tool for diagnosing the mixed acid-base disorders associated with the metabolic acidosis. Such diagnosis is important as a guide to know when to use bicarbonates [HCO[3]] to treat metabolic acidosis

Comparison between clonidine and verapamil as additives to local anesthetic for intravenous regional anesthesia

This study compared the effect of addition of clonidine or verapamil to 0.5% lidocaine for intravenous regional anesthesia [IVRA] on the onset of sensory and motor block, duration of postoperative analgesia, recovery of sensory function and hemodynamic response to tourniquet. Sixty patients scheduled for minor orthopedic surgery in the hand and forearm were randomly allocated into one of three groups. All patients received 40 ml of 0.5% of lidocaine together with 5 ml of an additive. The additive was saline in group A, clonidine 2 mug kg -1 in group B and 5 mg verapamil in group C. The results revealed that the onset of complete sensory block proved to be significantly faster in patients received clonidine and verapamil than the control group. The return of sensory function was significantly slower in clonidine group and verapamil group, the tourniquet pain scores were significantly better in clonidine and verapamil groups and the hypertensive response to the tourniquet was attenuated in both groups