Biomedical subjects
Publications and source records attributed to Anis S Baraka.
IMPLICATIONS: Supplementing a sevoflurane induction of anesthesia in children with IV lidocaine 2 mg/kg can suppress cough after tracheal intubation and thus improve intubating conditions. In addition, lidocaine minimizes blood pressure fluctuations after tracheal intubation.
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UNLABELLED: We compared, in volunteers, the oxygenation achieved by tidal volume breathing (TVB) over a 3-min period after maximal exhalation with that achieved by TVB alone. Twenty-three healthy volunteers underwent the two breathing techniques in a randomized order. A circle absorber system with an oxygen flow of 10 L/min was used. The end-expiratory oxygen concentration (EEO(2)) was monitored at 15-s intervals up to 3 min. TVB after maximal exhalation produced EEO(2) values of 68% +/- 5%, 75% +/- 5%, and 79% +/- 4% at 30, 45, and 60 s, respectively, which were significantly larger (P < 0.05) than the corresponding values obtained with TVB alone (58% +/- 5%, 66% +/- 6%, and 71% +/- 5%, respectively). In both techniques, the EEO(2) increased exponentially, with time constants of 35 s during TVB after maximal exhalation versus 58 s during TVB without prior maximal exhalation. In conclusion, maximal exhalation before TVB can hasten preoxygenation by decreasing the nitrogen content of the functional residual capacity, with a consequent increase of EEO(2) to approximately 70% in 30 s and 80% in 60 s. IMPLICATIONS: Oxygenation by using maximal exhalation before tidal volume breathing produced a significantly faster increase in end-expiratory oxygen concentration than oxygenation with tidal volume breathing alone.
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UNLABELLED: Forty-eight healthy parturients scheduled for elective cesarean delivery were randomly allocated to receive intrathecally either 12 mg of hyperbaric bupivacaine plus 12.5 microg of fentanyl (n = 23) or bupivacaine alone (n = 25). In the latter group, IV 12.5 microg of fentanyl was administered immediately after spinal anesthesia. We compared the amount of IV fentanyl required for supplementation of the spinal anesthesia during surgery, the intraoperative visual analog scale, the time to the first request for postoperative analgesia, and the incidence of adverse effects. Additional IV fentanyl supplementation amounting to a mean of 32 +/- 35 microg was required in the IV Fentanyl group, whereas no supple- mentation was required in the Intrathecal Fentanyl group (P = 0.009). The time to the first request for postoperative analgesia was significantly longer in the Intrathecal Fentanyl group than in the IV Fentanyl group (159 +/- 39 min versus 119 +/- 44 min; P = 0.003). The incidence of systolic blood pressure <90 mm Hg and the ephedrine requirements were significantly higher in the IV Fentanyl group as compared with the Intrathecal Fentanyl group (P = 0.01). Also, intraoperative nausea and vomiting occurred less frequently in the Intrathecal Fentanyl group compared with the IV Fentanyl group (8 of 23 vs 17 of 25; P = 0.02). IMPLICATIONS: Supplementation of spinal bupivacaine anesthesia for cesarean delivery with intrathecal fentanyl provides a better quality of anesthesia and is associated with a decreased incidence of side effects as compared with supplementation with the same dose of IV fentanyl.
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Cardiac diseases are present in 0.5-4% of pregnancies, and they remain a frequent cause of death during pregnancy. Pregnancy per se imposes significant hemodynamic changes, placing a major burden on the cardiovascular system. The early recognition and close follow-up of patients with cardiac diseases will improve maternal tolerance to the cardiovascular burden imposed by pregnancy, promote fetal growth and neonatal survival. Rheumatic heart disease remains the most frequent heart disease in the pregnant population with pulmonary edema as the most frequent complication. Atrial septal defect is the most frequent congenital heart disease in the adult population, whereas tetralogy of Fallot is the most common cyanotic congenital heart disease. An improvement in modern techniques of monitoring, a better understanding of the pathophysiology of cardiac disease, as well as multidisciplinary care has led to a substantial improvement in outcome of the pregnant cardiac patient. Management should be initiated before conception as it will provide optimal clinical conditions and sufficient information on the underlying pathophysiology.
PURPOSE OF REVIEW: This report reviews the derangements of neuromuscular transmission in the different types of myopathy. RECENT FINDINGS: The article covers recent literature on myopathy, whether prejunctional, junctional or postjunctional, as well as intensive care unit myopathy, and outlines the influence of myopathy on the action of both depolarizing and non-depolarizing muscle relaxants. SUMMARY: The review classifies myopathy according to its cause, and sheds light on the upregulation and downregulation of endplate acetylcholine receptors. These findings are important for both clinical practice, and for research into neuromuscular transmission.
BACKGROUND AND OBJECTIVES: The objective of the report is to monitor, in patients undergoing minimally invasive direct coronary artery bypass surgery (MIDCAB), the haemodynamic parameters, ST segment changes and the incidence of arrhythmias during clamping of the coronary artery and following reperfusion. METHODS: Twelve patients scheduled for elective MIDCAB surgery during isoflurane anesthesia were enrolled in the study. Patients were monitored by a pulmonary artery thermodilution catheter, an arterial line and 5 leads ECG. The different haemodynamic parameters, the ST segment changes, as well as the occurrence of arrhythmias during coronary clamping and ten minutes following reperfusion were compared to the control values. RESULTS: No significant changes in the cardiac index followed clamping of the coronary artery. However, the ST segment was significantly elevated. Following coronary reperfusion, the ST segment recovered to the baseline values, and the cardiac index significantly increased more than the baseline value (3.5 +/- 1.1 l/min/m2 vs 2.6 +/- 0.7 l/min/m2). However, reperfusion was associated with multiple ventricular extrasystoles in four patients. The elevation of the ST segments during coronary clamping was higher in the four patients who developed reperfusion arrhythmias (0.9 +/- 0.4 mm); one of the patients had preoperative frequent VPBs, two patients had history of unstable angina, while the fourth patient had 70% proximal stenosis of the LAD and recent myocardial infarction. CONCLUSIONS: Coronary occlusion in patients undergoing MIDCAB can result in ST segment elevation, followed by reperfusion ventricular extrasystoles. The reperfusion arrhythmias were observed in patients showing a significant elevation of the ST segment during coronary occlusion; risk factors included a preoperative history of arrhythmia, unstable angina, recent MI, and/or 70% LAD stenosis. The rapid restoration of the control ST segment level and the significant increase of cardiac output following coronary reperfusion suggest that isoflurane anesthesia may have provided a degree of myocardial protection during coronary clamping and reperfusion.
OBJECTIVE: Intrathecal morphine has been used for the relief of postoperative pain following cesarean delivery. We report a case of postoperative hypothermia down to 33.6 degrees C associated with excessive sweating in patient undergoing elective cesarean delivery under spinal bupivacaine anesthesia who received intrathecal morphine for postoperative pain management. CASE REPORT: A healthy 31-year-old multigravida presented for elective cesarean delivery. Following prehydration with 500 mL hemaccel, she had a subarachnoid block, using hyperbaric bupivacaine 12 mg and morphine 200 microgram, via a 25-gauge Whitacre needle. In the recovery room, 3 hours after induction of spinal anesthesia, the patient's sublingual temperature was 33.6 degrees C and she was noted to be sedated and sweating excessively. During the next 2 hours, the patient was still hypothermic despite active warming. She also complained of severe nausea, vomiting, and moderate pruritus. Following administration of naloxone 400 microgram sedation, vomiting, and pruritus were relieved. Also, the patient experienced excessive shivering, and her body temperature started to increase in association with a concurrent decrease of sweating. The postoperative hypothermia and excessive sweating in our patient may be related to the cephalad spread of the intrathecal morphine within the cerebrospinal fluid (CSF) to reach the level of opioid receptors in the hypothalamus, causing a perturbation of the thermoregulatory center. This effect could be counteracted by administration of naloxone. CONCLUSIONS: Intrathecal morphine may cause disruption of thermoregulation resulting in hypothermia associated with excessive sweating.