title: Non-invasive measurement of blood pressures in the Yucatan micropig (Sus scrofa domestica), with and without midazolam-induced sedation.
abstract: Current literature suggests that the effects of midazolam, a water-soluble benzodiazepine, on blood pressure in swine are minimal. The hypothesis of the study reported here was that a light sedative dose would induce a decrease in blood pressure in this species. Healthy female Yucatan Micropigs (n = 20), 16 to 30 (mean, 22) kg, aged four six months, were individually placed in a humane restraint sling and allowed to acclimate. Systolic (SBP), diastolic (DBP), and mean (MBP) blood pressures (mmHg) and heart rate (HR; beats per min [bpm]) were measured by use of oscillometry. The pressure cuff was placed at the base of the tail, and five sets of values were recorded at five-min intervals, beginning at 10 and ending 30 min after cuff placement. Following a three- to four-day rest period, this procedure was repeated with the addition of a dose of 0.5 mg of midazolam HCl/kg of body weight given intramuscularly at the time of cuff placement. A paired one-way Student's t-test was used to compare the means of the five measures between control and midazolam treatment. Mean (+/- SD) differences for SBP, DBP, MBP, and HR were 18.9 (+/- 3.97), 17.8 (+/- 5.27), and 18.6 (+/- 5.09) mmHg and 20.7 (+/- 3.73) bpm, respectively. All four parameters were significantly reduced in the midazolam-sedated group (P < 0.001). The maximal decrease in SBP, DBP, and MBP occurred at 15 and 20 min after dosing. Mean values based on the means of the five measures were 128 (+/- 12.6), 80 (+/- 9.4), and 99 (+/- 9.2) mmHg and 135 (+/- 17.4) bpm, and 109 (+/- 15.4), 63 (+/- 12.6), and 80 (+/- 13.6) mmHg and 115 (+/- 15.5) bpm for SBP, DBP, MBP, and HR in the control (n = 20) and midazolam (n = 20) groups, respectively. The control values can serve as normal oscillometric values for this age, sex, and breed of Micropig. We conclude that midazolam, given intramuscularly at a sedative dosage, negatively affects cardiovascular parameters measured by use of a blood pressure cuff, in sexually mature female Micropigs, compared with values in untreated pigs, which is similar to reports for humans.
authors.affiliation: Department of Comparative Medicine, Medical University of South Carolina, Charleston 29425, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Goodrich
authors.forename: D T
authors.initials: DT
authors.lastname: Lackland
authors.forename: M J
authors.initials: MJ
authors.lastname: Del Signore
authors.forename: M M
authors.initials: MM
authors.lastname: Swindle
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001795:Blood Pressure Determination / Q000379:methods / Q000662:veterinary*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008874:Midazolam / Q000494:pharmacology*; D013552:Swine; D013556:Swine, Miniature / Q000502:physiology*
chemical_list: D006993:Hypnotics and Sedatives; D008874:Midazolam