Efficacy of Ultrasound to Guide Management During a Rapid Response Event

Rapid response team systems have been implemented in numerous hospitals throughout the world with the goal of improving the identification and safety of hospitalized patients who are clinically deteriorating. Despite their theoretical benefit, rapid response systems have not been proven in the medical literature to ultimately change outcomes.

The traditional physical exam is helpful in evaluating and treating unstable medical patients during these types of events but has significant limitations of deceased sensitivity and specificity of findings. Ultrasound is a known tool for more accurately assessing patients in shock and respiratory failure in the ICU by highly trained operators but to the investigators knowledge has not been studied in the setting of rapid response events on hospital wards by critical care fellows after focused training. The investigators aim to assess the impact of ultrasound performed by critical care fellows during rapid response events.

This is an randomized controlled trial to determine if portable critical care ultrasound use is feasible, if its findings change clinical decision making by critical care fellows and whether ultrasound can improve patient outcomes during rapid response events at Beth Israel Medical Center.

Patients for whom a rapid response has been called for cardiac or respiratory failure will be randomized to either have a bedside ultrasound performed by a critical care fellow at the time of rapid response or to undergo a bedside ultrasound only if clinically indicated and specifically requested by the RRT leader.

For all patients on whom a rapid response is called with shock or respiratory failure who are randomized to the intervention group, a designated ultrasound critical care fellow will document their ranked top 2 preliminary cause for either shock or respiratory failure on a data collection instrument (DCI). These clinical (i.e. pre-ultrasound) diagnoses will be based on history, physical exam and all ancillary testing available prior to ultrasound performance. Available ancillary testing will be documented.

An ultrasound exam will then be performed by the designated ultrasound fellow using a portable hand-carried unit (GE Vscan) and the findings documented on the same DCI. The GE Vscan will be used for all ultrasounds performed during this study. The ultrasound study will take approximately 5 -10 minutes and will not interfere with alternative evaluation or treatment modalities deemed to be necessary during the rapid response.

The critical care ultrasound fellow will then provide the RRT leader team with their 2 most likely post ultrasound diagnosis for shock and respiratory failure and then document these on the DCI. Any changes to management made as a result of the ultrasound exam, including all new ancillary tests and therapeutic interventions will be recorded.

At 72 hours following the initial event the ICU or general medical attending physician will be asked to document the "final" diagnosis as to the cause of the initial shock or respiratory failure. This "final" diagnosis will serve as the "gold standard" to allow the assessment of accuracy of the pre-ultrasound and post-ultrasound diagnoses.

Patients randomized to the standard care group will not have an ultrasound performed at the time of rapid response unless it is deemed medically necessary by the responding RRT leader or critical care fellow. This is the current practice approach at the investigators hospital where ultrasound is performed only when clinically indicated.

The study investigators will obtain all DCI's as well as the final diagnosis from the attending physician at 72 hours, and will enter this data into a database that will not contain any unique patient identifiers.

The patient's time in respiratory failure and time in shock will be recorded as primary outcome measures. Secondary outcomes of in-hospital mortality, utilization of CT scan and chest x-ray in the 24 hours following rapid response and hospital length of stay will also be recorded. Also measured will be variability in pre and post-ultrasound diagnosis as well as changes in management following ultrasound performance.

Eligibility Criteria:
Inclusion Criteria: Patients for whom a rapid response is called who have:

1. Hemodynamic instability as defined by:

   * Systolic blood pressure less than 90 mmHg or less than 40 mmHg from previously established baseline
   * Heart rate greater than 130 beats per minute
   * Known elevated lactate above normal value.
2. Hypercapnic or hypoxemic respiratory failure as judged by the responding critical care fellow.

Exclusion Criteria: Patients for whom a rapid response has been called who:

1. Are not hemodynamically unstable and not in respiratory failure.
2. Are hemodynamically unstable but who have an obvious source of bleeding to explain hemodynamic instability.