The effects of acute L-carnitine administration on ventilatory breakpoint and exercise performanceduring incremental exercise

(Received 31 October, 2009 ; Accepted 10 March, 2010)AbstractBackground and purpose: Many athletes adopt nutritional manipulations to improve their performance. Among the substances generally consumed is carnitine (L-trimethyl-3-hydroxy-ammoniobutanoate) which has been used by athletes as an ergogenic aid, due to its role in the transport of long-chain fatty acids across mitochondrial membranes. Nutritional supplements containing carbohydrates, proteins, vitamins, and minerals have been widely used in various sporting fields to provide a boost to the recommended daily allowance. The aim of this study is to investigate the effects of acute L-carnitine administration on ventilatory breakpoint, an exercise performance during incremental exercise.Materials and methods: This study was double-blind, randomized and crossover in design. The subjects were 12 randomly selected active male physical education students, 21.75±0.64 years old, with a mean body mass index (BMI) of 23.7±0.94kg/m2, divided into 2 groups. They received orally either 2g of L-carnitine dissolved in 200 ml of water, plus 6 drops of lemon juice or a placebo (6 ml lemon juice dissolved in 200 ml of water) 90 minutes before they began to exercise on a treadmill. They performed a modified protocol of Conconi test to exhaustion. One-way analysis of variance with repeated measurements was used for data analysis.Results: The results showed that exercise performance improved in LC group (2980±155 meter) compared with placebo group (2331±51 meter). Furthermore, no significant difference was found in ventilatory breakpoint between the two groups.Conclusion: This finding indicates that administration of L- Carnitine, 90 minutes prior to exercise may improve performance; despite the ventilatory breakpoint as one of the anaerobic system indices that had no effect. J Mazand Univ Med Sci 2009; 19(73): 43-50 (Persian)

Echocardiography integrated ACLS protocol versus con-ventional cardiopulmonary resuscitation in patients with

【Abstract】Objective: To examine the utility of bedside echocardiography in detecting the reversible causes of pulseless electrical activity (PEA) cardiac arrest and pre-dicting the resuscitation outcomes. Methods: In this prospective interventional study, pa-tients presenting with PEA cardiac arrest were randomized into two groups. In Group A, ultrasound trained emergency physicians performed echocardiography evaluating cardiac activity, right ventricle dilation, left ventricle function, peri-cardial effusion/tamponade and IVC size along with the ad-vanced cardiac life support (ACLS) protocol. Patients in Group B solely underwent ACLS protocol without applying echocardiography. The presence or absence of mechanical ventricular activity (MVA) and evidences of PEA reversible causes were recorded. The return of spontaneous circulation (ROSC) and death were evaluated in both groups. Results: One hundred patients with the mean age of (58±6.1) years were enrolled in this study. Fifty patients (Group A) had echocardiography detected in parallel with cardiopulmonary resuscitation (CPR). Among them, 7 pa-tients (14%) had pericardial effusion, 11 (22%) had hypovolemia, and 39 (78%) were revealed the presence of MVA. In the pseudo PEA subgroup (presence of MVA), 43% had ROSC (positive predictive value) and in the true PEA subgroup with cardiac standstill (absence of MVA), there was no recorded ROSC (negative predictive value). Among patients in Group B, no reversible etiology was detected. There was no significant difference in resuscitation results between Groups A and B observed (P=0.52). Conclusion: Bedside echocardiography can identify some reversible causes of PEA. However, there are no sig-nificant changes in survival outcome between the echo group and those with traditional CPR. Key words: Heart arrest; Echocardiography; Car-diopulmonary resuscitatio