Study of Hypotensive Hematopoietic Malignancy Patients' USCOM Readings

Primary outcomes

1. What is the inter-rater agreement between multiple independent USCOM users measuring stroke volume (SV) and peak velocity (Vpk) whose systolic blood pressures (SBPs) and mean arterial pressures (MAPs) are stable (SBP above 95 mmHg and MAP above 65 mmHg)?

   Time frame: 1 day (one time event for patient)

   Pairs of USCOM measurements from multiple raters for SV and Vpk, both of which are interval-level measures. Inter-rater reliability will be assessed using the Intraclass Correlation Coefficient (ICC); our design fits into case 1 using the Shrout and Fleiss (1979) classification system.

2. What is the inter-rater agreement between multiple independent USCOM users measuring SV and Vpk in hematopoietic malignancy patients whose SBPs drop below 95mmHg or MAPs drop below 65mmHg?

   Time frame: 1 day (one time event for patient)

   pairs of USCOM measurements from multiple raters for SV and Vpk. We will use the ICC to evaluate rater agreement here, as well, with the same sample size and the same confidence interval. For Aim 2, though, if the second rating cannot be completed within 5 minutes of the first, that episode will be excluded from the study.

3. In what percentage of patients is fluid bolus administration successful as measured by the current standard of care (MAP) and what is the level of agreement between the standard measure and USCOM readings in determining return to hemodynamic stability?

   Time frame: 1 day (one time event for patient)

   After two raters have measured SV and Vpk, bolus will be administered. Determining the success of bolus administration, we will simply record whether the clinician judged the bolus to be successful. In addition, one rater will measure SV and Vpk again using USCOM within 5 minutes of bolus administration. We will then calculate the percentage of patients whose stroke volume and peak velocity increased at least 15% after bolus administration using the post-bolus USCOM reading and the same rater's pre-bolus USCOM reading. We chose an increase of 15% based on a review of the research as the threshold that would best indicate a therapeutic response to bolus administration.