Background: Interhospital transportation of critically ill patients is challenging. The risk incurred by the patient is compounded when stabilization and application of appropriate therapies are delayed. The purpose of this study was to first develop an interhospital intensive care unit (ICU) transfer instrument to systematize communication and determine feasibility of use. Then, the transfer instrument was tested for effects on patient mortality, stability on arrival, and recommended therapy implementation. Method: The instrument was developed and pilot tested for 6 months to optimize function and applicability. Then, a before-and-after quasi-experimental study tested this instrument by assessing several key outcomes. Outcomes measured included 48-hour mortality, ICU mortality, hospital mortality, emergent intubation, emergent central venous catheter insertion, immediate change in antibiotics, and addition of vasopressors immediately on arrival. Patients were compared by age, gender, cause for admission, and Acute Physiology and Chronic Health Evaluation (APACHE) II score. A standardized mortality ratio was calculated using the patient’s APACHE II score. Pretransport recommendations to referring physicians and adherence to recommendations were also measured. Results: The preintervention group consisted of 134 patients collected continuously over 6 months. The postintervention group was collected continuously over a 6-month period and included 77 patients. The interhospital ICU transfer instrument was associated with fewer emergent central venous catheter insertions and fewer changes in antibiotics on arrival. Recommendations to transferring physicians were followed 90% of the time. Conclusions: The interhospital ICU transfer instrument is a tool that is effective in coordinating the transfer of medical ICU patients. Implementation leads to timely critical interventions and may reduce mortality. [ABSTRACT FROM AUTHOR]