A vacuum release valve and method are defined. The monitor, which is non-invasive, comprises an optical fiber interferometer that includes an optical fiber proximately situated to the patient so that time varying acousto-mechanical signals from the patient are coupled into the optical fiber. The invention further relates to a method for qualitatively or quantitatively determining an analyte in such a liquid receptacle. These pivota+e wings are mechanically retracted out of the side curtain airbag; deployment zones in the event of an airbag deployment event.