 1. Treatment study: The study will follow the standard operating procedure of Good Clinical Practice, including a clinical monitor from Oslo University Hospital, Ullevål who will provide study quality assurance in all centers. Two main groups randomised into RA vs saline, each divided into two arms of the active drugNaCl groups: fixed or on demand inhalations. The trial will be double blinded by the pharmacy. One glass with sufficient medication for the entire hospital stay will be designated per patient throughout. No cross-over. Outcomes will be analysed by intention to treat, with treatment given and recorded throughout the hospital admission. No interim analyses are planned since the study compares two established treatment modalities used for the last decades. 