Sulphur hexafluoride

Specific investigations: other studies

Description of key information

The assessment of cardiac sensitisation potential of sulphur hexafluoride in dogs revealed no sign of cardiac sensitisation at concentrations up to 20%. Ophthalmologic examination in rabbits exposed to SF6 revealed endothelial lesions in the corneal tissue which is attributed to contamination with S2F10 / fluorinated degradation products of SF6 formed by LASER irradiation. SF6 as such does not cause endothelial lesions.

Additional information

Cardiac sensitisation

Cardiac sensitisation potential of SF₆was studied by Mullin and Trochimowicz (1972). 12 dogs were exposed via face mask to 20% SF₆. Animals were injected with 0.0008 mg/kg bw adrenaline before the exposure and 5 minutes after the beginning of the exposure. Electro-cardiogram recording was performed during the experiments. No sign of cardiac sensitisation was observed in exposed dogs.

Anaesthetic potential

Anaesthetic potential of SF₆was assessed in five dogs by Eger et al. (1969). The minimum alveolar concentration (MAC) necessary to eliminate movements in response to a painful stimulus was 4.9 ± 0.4 atm.

Ophthalmological application

The toxic potential of SF₆ used as a tamponade gas in ophthalmology was assessed in rabbits by Schulze and Schmidtdorf (1989). Formation of SF₆ bubbles was observed in the eyes of exposed animals. Microscopic examinations revealed the occurrence of clouding areas in the cornea of the eyes insufflated with SF₆, in correspondence with the formation of the bubbles. In vitro post mortem examination revealed endothelial lesions in all corneal tissue of eye treated with SF₆ in comparison to control samples. Endothelial cell areas with damage or regeneration changes were recorded in SF₆ treated eye. The authors indicated the contamination of SF₆ with S₂F₁₀ as a possible explanation for the toxic effects. SF₆ as such does not cause endothelial lesions.

The possible cytotoxic effect of ophthalmological use of SF₆ in LASER surgery was assessed in vitro by Gripphits et al. (1987). Human retinal pigment epithelial (REP) cells were cultured in a flask and exposed to an atmosphere containing SF₆ or air. Nd:YAG-LASER radiation was used to form 100 plasmas in the gas at a site distant from the cell layer. An almost complete cellular death was observed in samples containing SF₆and irradiated with LASER, whereas no adverse effects were observed by directly exposing cells to air or to the gas alone. The effect was attributed by the authors to the formation of fluorinated degradation products with cytotoxic potentials; breakdown of sulphur hexafluoride is known to occur under the conditions of electric arcing. Such conditions are not relevant for the risk characterisation of SF₆ under REACH. SF₆ as such does not cause endothelial lesions.