Patients in the medical intensive care unit (MICU) often receive arterial lines as standard of care, however there are little data to support this practice. Investigators will randomly assign consecutive weeks to either current practice(control) or to a more conservative practice of not placing invasive arterial lines except for limited indication indications as defined below (intervention). Patients entering during an intervention week will be treated according to the intervention practice throughout their ICU stay. Likewise, patients entering during a control week will be treated according to current standard practice.~Permuted block randomization will be used to assure equal numbers of intervention and control weeks. All outcome measures will be obtained through EPIC data analytics and post-hospitalization phone calls. Weekly randomization codes will be generated by the study statisticians and delivered to MICU staff via sealed envelopes to be opened at the beginning of each week.
Investigators will conduct a pragmatic randomized trial to investigate the non-inferiority of restricted use of invasive arterial lines compared to standard arterial line use.