Preliminary evaluation of tear production in dogs hospitalized in an intensive care unit

To determine the tear production in dogs admitted to an intensive care unit (ICU).

Prospective observational study from November 2010-September 2011.

Private emergency and referral hospital.

Thirty healthy control dogs and 30 dogs hospitalized in an ICU for treatment of systemic illness without previously diagnosed ophthalmic disorders and no recent history of anesthesia. Enrollment was based on availability of the ophthalmologist within 24 hours of admission to the ICU.

Tear production was measured utilizing Schirmer tear test strips (STT) in healthy control animals as well as in hospitalized canine patients. All patients received an ophthalmic examination by a board-certified veterinary ophthalmologist within 24 hours of admission to the ICU. Lubrication with artificial tear gel every 2-4 hours as needed was implemented after STT was measured.

Average tear productions in the control and canine ICU populations were 24.5 mm/min and 13.2 mm/min, respectively. This was found to be statistically significant (P < 0.001). Furthermore, there was a trend toward a decrease in tear production in patients with kidney disease and a trend toward normal tear production in patients with cardiac disease but the sample size was likely too small to enable detection of a statistically significant difference.

This study demonstrates a decrease in tear production in canine ICU patients. While further study is warranted to determine how different diseases impact tear production, these finding support the implementation of frequent ocular lubrication in all ICU patients.