Confronting the Effects of 0.9% Saline Administration on Breathing

Abstract

Saline (0.9%) is regularly used in hospitals and research settings as a resuscitation solution or as a conduit to administer compounds to patients or subjects. Preliminary data in our laboratory suggested dissimilar ventilation following short‐term i.p. saline administration (n=4) compared to non‐injected (n=6) mice (frequency: 111±15 vs. 126±4 breaths/min; tidal volume (TV): 0.31±0.02 vs. 0.35±0.01 mL/breath; minute ventilation (MV): 35.1±5.9 vs 43.9±1.4 mL/min). In addition, previous reports suggest that the addition of 0.9% saline could induce changes in pH, possibly altering breathing. We tested the hypothesis that ventilation would be higher in mice prior to saline administration compared to after saline administration. Utilizing unrestrained barometric plethysmography, we tested 18 week old CD‐1 male mice prior to intervention and following 7 days of 0.9% saline (i.p., 10mL/kg body mass) during exposure to room air. Values are reported as MEAN ± SEM; p<0.05; n=4. There were no differences when comparing PRE vs. POST saline in frequency (137±9 vs. 142±10 breaths/min, TV (0.46±.01 vs. 0.52±.02 mL/breath), or MV (62.5±3.8 vs. 72.5±7.7 mL/min). Conscious blood gas sampling showed no differences between 7 days of saline administration (pH: 7.46±0.00; PaCO2: 29.3±2.3) and 1 day of washout (pH: 7.39±0.03; PaCO2: 39.1±4.6). Our preliminary findings indicate no impact of saline administration on the pattern of breathing during exposure to room air. Funding: Le Moyne College Student Research Committee and McDevitt Center Research Fellowship in Natural Science (TG).