Not as big a problem as suggested.
It is impossible to asses the ipact of this without an understanding of the intended use of the device but it is almost certainly the case that if it is being used as a vital signs monitor it will have a local audible alarm and alert feature. These must be there because the network/wireless communications cannot be relied upon. Yes misleading information could be fed into the remote monitoring system and this might be a factor in misleading clinicians but the same clinicians will still use visual observations and information from many other sources. In addition advice from the manufacturers will certainly include sensible security measures on the hospital network.