Melatonin premedication and the induction dose of propofol.

BACKGROUND AND OBJECTIVES: Melatonin (N-acetyl-5-methoxytryptamine) is the main indolamine secreted by the pineal gland. Many studies showed that premedication with melatonin is associated with preoperative anxiolysis and sedation without impairment of cognitive and psychomotor skills and without prolonging recovery. We hypothesized that melatonin decreases the amount of propofol required to produce an adequate depth of hypnosis at induction time. METHODS: After approval from the research committee of the anaesthesia department, informed written consent was taken from 45 adult patients undergoing different surgical procedures. They were allocated randomly into three groups according to the premedication. At 100 min preoperatively, premedication was given in the form of oral melatonin 3 mg (M3 group), oral melatonin 5 mg (M5 group) or no premedication (P group). After preoxygenation an anaesthesiologist who was blinded to the premedication injected propofol 10 mg over 5 s every 15 s until the bispectral index (BIS) score fell to 45. The total dose of propofol required to achieve a BIS score of 45 was recorded. Response to verbal commands and eyelash reflex was evaluated and correlated to the BIS score and propofol dosage. When a BIS score of 45 was reached, tracheal intubation was accomplished after administration of a narcotic and muscle relaxant. RESULTS: The mean (standard devitation (SD)) induction dose of propofol producing a BIS score of 45 was 134 (25) mg in the placebo group vs. 115 (19.5) and 114 (20.9) mg in the M3 and M5 groups, respectively (P < 0.05). The propofol dose required to achieve loss of eyelash reflex and loss of response to verbal commands was more in the placebo group. Anxiety score as assessed by visual analogue scale (VAS) scored more in the placebo group than both melatonin groups. Time spent in the recovery room did not differ between the three groups. CONCLUSION: Melatonin premedication, in an oral dose of either 3 or 5 mg, reduced the required dose of propofol to achieve a BIS score of 45, reflecting a sufficient level of hypnosis for tracheal intubation without prolongation of postoperative recovery room stay.

[Blood rheologic properties in patients with dilated cardiomyopathy]. / Reologicheskie svoistva krovi u bol'nykh dilatatsionnoi kardiomiopatiei.

Rheologic blood parameters--fluidity limit tau 0, viscosity n alpha 1, erythrocyte cohesion coefficient (A), hematocrit--were studied in 42 patients with dilated cardiomyopathy (DCM) and 30 patients with ischemic heart disease (IHD) and heart failure of stages I-III. Rheologic parameters tended to increase along with progression of heart failure while in IHD an opposite tendency was observed. Individual analysis in patients with DCM as well as those with IHD demonstrated, irrespectively of the stage of heart failure, both hyper- and hyporheological syndromes. Occurrence of thromboembolic complications was in both cases nearly the same (42.9% and 40%, correspondingly). The data obtained indicate at evident abnormality of rheologic blood parameters in patients with dilated cardiomyopathy progressing along with development of heart failure and suggest its possible role in intravascular thrombi formation.

[Disorders of heart rhythm and conduction in dilated and hypertrophic cardiomyopathies]. / Narusheniia ritma i provodimosti serdtsa pri dilatatsionnoi i gipertroficheskoi kardiomiopatii.

Idiopathic cardiomyopathies are characterized by diversity of clinical manifestations, among which heart rhythm abnormalities are the most common. The authors carried out qualitative and quantitative evaluations of heart rhythm abnormalities in patients with dilated and hypertrophic cardiomyopathies (DCMP, HCMP) and compared those abnormalities according to the data of daily ECG monitoring. Forty patients with DCMP and 30 with HCMP were examined. In 8 (25%) patients with DCMP and in 2 (6.7%) with HCMP, permanent atrial fibrillation was recorded. Among patients with sinus rhythm, supraventricular premature heart beats were found in 30 (96.8%) patients with DCMP and in 24 (85.7%) with HCMP. However, their number during 24 h exceeded 500 in 9 (29%) and in 7 (25%) patients, respectively. Supraventricular paroxysmal tachycardia (greater than or equal to 3 complexes at HR greater than or equal to 100/min) was recorded in 7 (22.6%) patients with DCMP and in 4 (14.3%) patients with HCMP. Ventricular premature heart beats were recorded in 38 (95%) patients with DCMP and in 21 (70%) patients with HCMP, polytopic in 31 (77.5% and 17 (56.7%), coupled in 227 (67.5%) and 10 (33.3%), ventricular paroxysmal tachycardia (greater than or equal to 3 complexes at HR greater than or equal to 100/min) in 22 (55%) and 5 (16.7%) patients, respectively. AV conduction abnormalities among patients with sinus rhythm were noted in DCMP and HCMP, in 12 (38.7%) and 1 (3.6%) cases, respectively. Thus, heart rhythm abnormalities are often encountered in both patients with DCMP and HCMP. However, in patients with DCMP, heart arrhythmias are graver and prognostically unfavourable.(ABSTRACT TRUNCATED AT 250 WORDS)