Non-invasive monitoring of pH and oxygen using miniaturized electrochemical sensors in an animal model of acute hypoxia

Abstract Background One of the most prevalent causes fetal hypoxia leading to stillbirth is placental insufficiency. Hemodynamic changes evaluated with Doppler ultrasound have been used as a surrogate marker hypoxia. However, evaluation cannot be performed continuously. As first step, present work aimed evaluate performance miniaturized electrochemical sensors in continuous monitoring oxygen and pH model acute hypoxia-acidosis. Methods were ventilatory rabbit model. The ventilator protocol included 3 differential phases: basal (100% FiO 2 ), hypoxia-acidosis period (10% ) recovery ). Sensors tested blood tissue (ex vivo sensing) muscular (in sensing). on day insertion (short-term evaluation) also after 5 days (long-term evaluation). sensing registered throughout (basal, hypoxia-acidosis, recovery) compared gas metabolites results from carotid artery catheterization (obtained EPOC analyzer). Finally, histological assessment was sensor site. One-way ANOVA for analysis evolution acid-based signaling results; t-test pre- post-calibration analyses; chi-square analyses categorical variables. Results At short-term evaluation, both distinguished periods ex sensing. only detected period. In long-term signal seemed lose sensibility. revealed no signs alteration (short-term), whereas sub-acute inflammatory reaction adjacent implantation site detected. Conclusions Miniaturized represent new generation tools which especially indicated high-risk pregnancies. Further studies including more tissue-compatible material would required order improve