Effects of intravenous and topical laryngeal lidocaine on heart rate, mean arterial pressure and cough response to endotracheal intubation in dogs.
OBJECTIVE
To compare the effects of intravenous (IV) and topical laryngeal lidocaine on heart rate (HR), mean arterial pressure (MAP) and cough response to endotracheal intubation (ETI) in dogs.


METHODS
Prospective, randomized, blinded clinical study.


METHODS
Forty-two client-owned dogs (American Society of Anesthesiologists class I and II status) undergoing elective orthopaedic surgery.


METHODS
Dogs were randomized to three groups. Dogs in group SALIV received 0.1 mL kg(-1) IV saline. Dogs in group LIDIV received 2 mg kg(-1) IV 2% lidocaine. Dogs in group LIDTA received 0.4 mg kg(-1) topically sprayed laryngeal 2% lidocaine. All dogs were premedicated with methadone (0.2 mg kg(-1) IV). After 30 minutes, IV propofol was administered to abolish the lateral palpebral reflex and produce jaw relaxation. The allocated treatment was then administered and, after 30 seconds, further propofol was administered to abolish the medial palpebral reflex and facilitate ETI. HR and MAP were measured at four time-points using cardiac auscultation and automated oscillometry, respectively. The cough response at ETI was recorded. One-way anova and post hoc Tukey adjustment were used to analyse parametric data. The Kruskal-Wallis test was used to analyse non-parametric data. Odds ratios were calculated for the cough response. A p-value of ≤0.05 was considered to indicate statistical significance.


RESULTS
In response to ETI, changes in MAP differed significantly between groups. In SALIV, MAP increased (4 ± 6 mmHg), whereas it decreased in LIDIV (6 ± 13 mmHg) (p = 0.013) and LIDTA (7 ± 11 mmHg) (p = 0.003). Dogs in SALIV were almost 10 times more likely to cough than dogs in LIDIV (odds ratio 9.75, 95% confidence interval 0.98-96.60; p = 0.05).


CONCLUSIONS
In propofol-anaesthetized dogs, IV and topical laryngeal lidocaine attenuated the pressor response to ETI, whereas IV lidocaine reduced the cough response.
Department of Veterinary Anaesthesia, Small Animal Teaching Hospital, University of Liverpool, Liverpool, UK.
Kate R
KR
Thompson
Department of Veterinary Anaesthesia, Small Animal Teaching Hospital, University of Liverpool, Liverpool, UK.
Eva
E
Rioja
D000287:Administration, Topical; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D062186:Arterial Pressure / Q000187:drug effects*; D003371:Cough / Q000209:etiology / Q000662:veterinary*; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007275:Injections, Intravenous / Q000662:veterinary; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000662:veterinary*; D007830:Larynx / Q000187:drug effects; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D015742:Propofol / Q000008:administration & dosage; D011446:Prospective Studies; D012018:Reflex / Q000187:drug effects; D018709:Statistics, Nonparametric
D018686:Anesthetics, Intravenous; D006993:Hypnotics and Sedatives; D008012:Lidocaine; D015742:Propofol
cough; intravenous lidocaine; intubation; laryngotracheal lidocaine; pressor response