Quantitative accuracy of the simplified strong ion equation to predict serum pH in dogs

Background

Electrochemical approach to the assessment of acid‐base states should provide a better mechanistic explanation of the metabolic component than methods that consider only pH and carbon dioxide.

Hypothesis/Objectives

Simplified strong ion equation (SSIE), using published dog‐specific values, would predict the measured serum pH of diseased dogs.

Animals

Ten dogs, hospitalized for various reasons.

Methods

Prospective study of a convenience sample of a consecutive series of dogs admitted to the Massey University Veterinary Teaching Hospital (MUVTH), from which serum biochemistry and blood gas analyses were performed at the same time. Serum pH was calculated (Hcal+) using the SSIE, and published values for the concentration and dissociation constant for the nonvolatile weak acids (A_tot and K_a), and subsequently Hcal+ was compared with the dog's actual pH(Hmeasured+). To determine the source of discordance between Hcal+ and Hmeasured+, the calculations were repeated using a series of substituted values for A_tot and K_a.

Results

The Hcal+ did not approximate the Hmeasured+ for any dog (P = 0.499, r² = 0.068), and was consistently more basic. Substituted values A_tot and K_a did not significantly improve the accuracy (r² = 0.169 to <0.001). Substituting the effective SID(Atot−[HCO3−]) produced a strong association between Hcal+ and Hmeasured+ (r² = 0.977).

Conclusions and clinical importance

Using the simplified strong ion equation and the published values for A_tot and K_a does not appear to provide a quantitative explanation for the acid‐base status of dogs. Efficacy of substituting the effective SID in the simplified strong ion equation suggests the error lies in calculating the SID.

Crossover clinical trial to determine the effect of manual acupuncture at Siguan points (bilateral LI4 and LR3) on intestinal motility in healthy subjects

This study examined whether manual acupuncture at the Siguan points (bilateral points LI4 and LR3) affects intestinal motility in healthy human subjects. Twenty healthy male subjects were randomly assigned either to real acupuncture (RA) at Siguan points or sham acupuncture (SA) groups in a crossover manner. All subjects underwent two experimental sessions; the RA group in the first session was treated with SA in the second session after a 2-week washout period, and vice versa. Each subject took 20 radio-markers and was treated with acupuncture 0, 12, 24, and 36 hours after radio-marker intake. Radiographs were taken at 6, 12.5, 24.5, and 48 hours, and the effect of acupuncture on intestinal motility was evaluated based on the distribution of the radio-markers in the ileum, ascending colon, transverse colon, descending colon, sigmoid/ rectum, and outside the body. Defecating habit was monitored during the trial, and complete blood counts were checked before and after the two acupuncture sessions. The RA and SA results showed extremely similar distributions of the radio-markers in these five regions of the alimentary canal and outside the body in radiographs taken at four different times, verifying that there was no effect of manual acupuncture at the Siguan points on intestinal motility, at least in healthy human subjects.