{'fraction_non_alphanumeric': 0.028092656481025137, 'fraction_numerical': 0.011335633316904879, 'mean_word_length': 5.304347826086956, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Effect of a constant rate infusion of remifentanil hydrochloride on left ventricular systolic and diastolic function in propofol-anesthetized dogs.

OBJECTIVE To assess the effects of a constant rate infusion (CRI) of remifentanil hydrochloride on left ventricular systolic and diastolic function in healthy propofol-anesthetized dogs. ANIMALS 6 healthy Beagles. PROCEDURES Each dog underwent 2 experimental treatments separated by a 7-day interval. In 1 treatment, anesthesia was induced with propofol and maintained with a CRI of propofol (0.6 mg/kg/min); dogs also received a CRI of saline (0.9% NaCl) solution. In the other treatment, anesthesia was similarly induced and maintained with propofol; dogs also received a CRI of remifentanil (0.3 μg/kg/min). Doppler echocardiographic and hemodynamic variables of interest were determined at baseline (before anesthesia) and at 20, 40, and 60 minutes following the simultaneous start of the 2 CRIs of each treatment; all CRIs were administrated for 60 minutes. RESULTS For the 2 treatments, end-diastolic and end-systolic volume indices did not differ from baseline or at any time point. Peak tissue Doppler-derived mitral annulus systolic velocity decreased from baseline with both treatments; however, no differences were found between treatments at any time point. Mean arterial blood pressure decreased similarly with both treatments. Heart rate and Doppler-determined cardiac index decreased significantly with the propofol-remifentanil treatment, compared with findings for the propofol-saline solution treatment. For the propofol-remifentanil treatment, the ratio of peak velocity flow in early diastole to that in late diastole remained > 1.80, whereas the ratio of early to late Doppler-derived mitral annulus velocity had a normal relaxation pattern. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study indicated that a CRI of remifentanil administered along with a CRI of propofol does not impair left ventricular systolic and diastolic function in healthy dogs.