Collateral damage: Cardiovascular and respiratory implications of tear gas deployment during peaceful protest

In December 2024, large-scale protests in front of Georgia's Parliament were met with crowd-control measures involving the widespread use of tear gas and pepper spray, mixed with water. This study examined whether protest participants exposed to these agents exhibited electrocardiographic, capillaroscopic, or hematologic abnormalities, and explored associations with allergy status, mask use, and attendance frequency.

An observational case-control study was conducted from January 9 to March 1, 2025. Of 347 protest participants surveyed, 69 underwent clinical evaluation. A control group of 31 unexposed individuals was recruited. Participants received ECGs, capillaroscopy, complete blood count (CBC), and coagulogram testing. Data were analyzed using chi-square tests, eta coefficients, and t-tests (p < 0.05).

ECG abnormalities-including P-wave (p < 0.001), QRS complex (p = 0.035), and T-wave (p = 0.012) changes-were significantly more frequent in the exposed group. Right bundle branch block and T-wave inversions were particularly notable. Capillaroscopy showed more non-specific and sclerodermal abnormalities in the exposed group, though not statistically significant. Allergy status was linked to higher symptom burden, while mask use and attendance frequency were not predictive. Laboratory parameters were largely normal. Two respiratory cases-hypersensitivity pneumonitis and unresolved pneumonia-were clinically linked to exposure.

Exposure to CS gas was associated with significant ECG changes, indicating potential cardiopulmonary effects. Clinical patterns and rare respiratory cases warrant re-evaluation of chemical agent use, improved oversight, and long-term studies to assess chronic health risks in exposed populations.