Tehran University Medical Journal

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Background: The Bispectral Index (BIS) is an EEG-derived value that measures the sedative and hypnotic component of the anesthetic state. The effects of age on the bispectral index have not been well documented. The objective of the present study was to determine the influence of age on hypnotic requirement and bispectral index in awake and in patients with sedation induced by midazolam.

Methods: Eighty patients were enrolled in this prospective observational study. The patients in study group were aged more than 70 years, and the age in control group ranged 20-40 years. Baseline recording of BIS was taken in awake patients in two groups for few minutes. Five minutes after administration of 0.02 mg/kg IV midazolam the BIS value also was taken and recorded.

Results: In the study group, patients had a mean base BIS 94±3 compared with 97.3±1 in the control group (p< 0.0001). Five minutes after administration of 0.02 mg/kg midazolam the value were 80.9±6 and 90.4±3 respectively (p< 0.0001).

Conclusion: When BIS is used as a monitor of hypnosis in the elderly, we recommend that a baseline recording be taken before induction for a few minutes to alert the anesthesia provider to the possibility of low initial values. Further studies are needed to verify if the recommended range of 50-60 of BIS during clinical anesthesia is also adequate in the elderly with low initial baseline BIS or if this range needs adjusting in view of reduced initial BIS value.

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Background: Non-steroidal anti-inflammatory drugs (NSADs) and opioids are frequently administered to relieve postoperative pain. Uncontrolled postoperative pain may produce a range of detrimental acute and chronic health consequences and increase mortality and morbidity. Practically, the analgesic efficacy of opioids is typically limited by the development of tolerance to them or by opioid-related side- effects such as nausea, vomiting, sedation or respiratory depression. This study aims to assess the effects of suppository diclofenac on post-herniorrhaphy pain management. Methods: In this prospective double-blind clinical trial, 60 patients who were candidate for the surgical repair of inguinal hernia were divided into two groups. Patients in group A received 100 mg of suppository diclofenac and patients in group B 50 mg of pethidine after the induction of anesthesia and before surgical incision. Postoperative pain assessment was done by an unbiased observer on the arrival of patients in the recovery room, using a 10-cm visual analogue scale (VAS) at 2-hour intervals for 6 hours. Results: Pain relief was similar in the two groups (P=0.3). Patients in group B required more analgesia two hours post-operatively (P=0.03), while patients in group A had more favorable results regarding pain control (P<0.05). Statistically, there was no difference between the two groups at other intervals. The occurrence of nausea and vomiting was similar in both groups. No respiratory depression was observed in the patients. Conclusion: Preventive analgesia with 100 mg of suppository diclofenac after anesthesia induction for herniorrhaphy produced effective postoperative analgesia with minimum side-effects

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Background: Perioperative administration of tranexamic acid (TA), decreases bleeding and the need for transfusion after cardiac procedures. Hence, the results may vary in different clinical settings and the most appropriate timing to get the best results is unclear. The primary objectives of the present study were to determine the efficacy of TA in decreasing chest tube drainage, the need for perioperative allogeneic transfusions and the best timing for TA administration following primary, elective, coronary artery bypass grafting (CABG) in patients with a low baseline risk of postoperative bleeding.

Methods: In this double-blind, prospective, placebo-controlled clinical trial in Seiedoshohada Hospital during 2011-2012, we evaluated 150 patients scheduled for elective, primary coronary revascularization. They were randomly divided into three groups. Group B received tranexamic 10 mg/kg prior to, Group A received tranexamic acid 10 mg/kg after cardiopulmonary bypass and group C received an equivalent volume of saline solution. Blood requirement and postoperative chest tube drainage were recorded.

Results: The placebo group (group C) had a greater postoperative blood loss 12 h after surgery (501±288 vs. 395±184 in group B and 353±181 mL in group A, P=0.004). The placebo group also had greater postoperative total blood loss (800±347 vs. 614±276 in group B and 577±228 mL in group A, P=0.001). There was a significant increase in allogeneic blood requirement in the placebo group (P=0.001).

Conclusion: For elective, first time coronary artery bypass surgery, a single dose of tranexamic acid before or after cardiopulmonary bypass is equally effective.

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Background: Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO2 (puls-eoximetry oxygen saturation) in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation (SaO2) during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship.
Methods: In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO2 was recorded and compared with SaO2 obtained by blood gas analysis. One or serial arterial blood gas analyses (ABGs) were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO2 and SPO2 we recorded.
Results: O2 saturation as a marker of peripheral perfusion was measured by Pulseoxim-etry (SPO2). The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12%±1.6%. A total of 137 paired readings demonstrated good correlation (r=0.754 P<0.0001) between changes in SPO2 and those in SaO2 in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation (r=0.799 P<0.0001) and the mean difference between SaO2 and SPO2 was 0.05%±1.5%.
Conclusion: Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn’t alter the relation between SPO2 and SaO2 to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.