Blood gas sampling errors during exercise.

This research article critique reviews two other studies by Tate et al. on the collection of arterial blood from horses during exercise for blood gas and pH evaluation. The author questions the techniques used in these studies, the assumptions made about the differing metabolic processes between treadmill and track running, the inappropriate statistical analyses used, and the lack of validation for blood sampling methods.

Questioning the Assumptions about Metabolic Differences

• The author casts doubt on the assumption made by Tate et al. regarding significant differences in the metabolic work when a horse is running on a treadmill versus a track or turf. According to the critique, such differences have not been empirically proven even though they might be hypothetically possible.
• The author explains that treadmills are commonly used for such physiological experiments due to their ability to provide a controlled metabolic load on the animal. The argument is made that any differences in metabolic power required to run the same distance may be down to ground compliance or differences between treadmills, not the inherent difference between treadmill and track running.

Dismissing Statements about Acid-Base Changes

• Contrary to Tate et al.’s statement that previous studies show no consistent patterns of acid-base changes in exercising versus resting horses, the author asserts that consistent patterns in pH and blood gases are evident in mammals at different exercise intensities when adjustments for temperature are correctly applied.

Pointing Out Errors in Temperature Correction

• The critique also brings attention to apparent inconsistencies or errors in the way Tate and co. have applied temperature corrections to their blood gas data. The author suggests that by virtue of using rectal temperatures for these corrections, instead of blood temperatures, all the exercise data reported by Tate et al. may be invalid.

Discussion on Statistical Analyses

• The critique suggests that Tate et al.’s statistical analyses are flawed. Due to multiple measurements taken on the same animals in their studies, the data is not independent. Therefore, the critique suggests that Tate and his team should have used a repeated measures analysis of variance instead.
• The author further comments on the incorrect application of the Student’s t test for multiple comparisons in the studies, suggesting that Tate’s team should have used a multiple-range test or adjusted their test statistic via a correction method.

Doubts over Blood Sampling Methods

• Finally, the critique expresses doubts over the blood sampling methods used by Tate et al. The author disputes the assumption that the spring-loaded syringes used for the sample collection provided an anaerobic and unbiased sample of blood. The critique suggests that there is no data supporting this claim, and no idea of the degree of contamination in the samples.