Pulse oximetry and venous blood gas analysis of 119 dogs diagnosed with the paralysis tick Ixodes holocyclus

Authors: Reddrop C, Webster R, Epstein SE
Publication: Australian Veterinary Practitioner, Volume 53, Issue 4, pp 114-121, Oct 2023
Publisher: Australian Veterinary Association

Animal type: Dog
Article class: Clinical Article

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Abstract:

Tick paralysis effects many domestic species along the East Coast of Australia each year. Despite its clinical prominence, an evaluation of pulse oximetry and venous blood gas analysis, including specific tick distribution on presentation has not been previously investigated. Data was collected retrospectively from 119 dogs with an engorged paralysis tick showing clinical signs of tick paralysis on presentation. The location of a tick(s) was recorded, including their incidence once clipped in hospital. The hypothesis was there would be a significant difference between low and high tick scored groups for pulse oximetry and PvCO2 only. A significant difference was seen for pulse oximetry between respiratory score B (median 98%) and C (median 95.5%), and between a gait score 1 (median 98%) and 3 (median 96%). No difference was seen between groups for PvCO2. Of the dogs hospitalised presenting with a respiratory score of 3 or C, 20% required mechanical ventilation despite having an SpO2 >97% on presentation. Given the exclusion criteria for the study, only a single case was seen with a respiratory score D and gait score 4. Tick distribution on presentation identified 46.5% of ticks were found on the head with 17.5% found second most common on the neck, and 9.6% having two ticks.

Keywords: tick paralysis, blood gas, pulse oximetry, hypoxaemia

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