Hemodynamic Monitoring in the ICU

Abstract

Management of the unstable patient is one of the greatest challenges in medicine. At stake is the very life of the patient: treat wisely and your patient will benefit; choose poorly and your patient may suffer. Ultimately, the management of any critically ill patient returns to a single, central question: “What is making my patient unstable?” Unfortunately, this very question is one of the most difficult to answer. In part, it is a difficult question because our patients may be unstable for a variety of competing reasons. Even more challenging, a few patients are unstable for a combination of these reasons. Understanding the vectors of the forces that affect a patient’s hemodynamics is the key to selecting the management strategy that will provide the most benefit (and do the least harm). In order to make the most intelligent choices possible, a clinician must always seek to better understand the forces at work inside the body. The delicate interplay between intravascular volume, cardiac function, and vasomotor tone can be difficult to assess. Scientists and engineers have been working for decades to develop a device that can accurately and easily measure a patient’s hemodynamic profile. Unfortunately, as of the publication of this textbook, that technology does not exist. Each device or technique is victim to its own specific set of strengths, weaknesses, and complications of use. Critical measurements are often made indirectly or with some degree of estimation. It is imperative that the clinician understands the capabilities of each instrument and when to apply it to a particular patient.