AACN clinical issues
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The resuscitation of critically ill patients frequently requires the administration of fluids for the purpose of increasing cardiac output and oxygen delivery to the tissues. The assessment of the patient's preload status during this process is vital. Traditionally, preload assessment has been through the use of right atrial pressure and pulmonary artery occlusion pressure, which are often referred to as the "filling pressures." The use of these filling pressures is based upon the assumption that ventricular compliance does not change. ⋯ The volumetric parameters are presented followed by a discussion of research supporting the use of the volumetric parameters in lieu of pressure measurements for preload assessment in a variety of patient populations. The technology providing continuous RVEDV measurements is presented followed by a discussion of a case study demonstrating the value of continuous measurements. Specific implications for the advanced practice nurse are addressed.
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AACN clinical issues · May 2003
Review Case ReportsContinuous nervous system monitoring, EEG, the bispectral index, and neuromuscular transmission.
In critically ill patients, the central nervous system remains vulnerable to multiple insults including ischemia, hemorrhagic events, and encephalopathy. The peripheral nervous system is vulnerable in the setting of neuro-muscular blockade (NMB), related drug-drug interactions, and drug-clinical state interactions. Optimal assessment of the nervous system is done by means of the clinical neurological examination. ⋯ Neuromuscular transmission (NMT) monitoring by means of peripheral nerve stimulation and assessment of the evoked response may be utilized, within the context of clinical assessment, to determine level of chemical paralysis and minimize dosing of NMB agents. This article explores utilization and differentiates technologies such as EEG, BIS, and NMT monitoring. Monitoring parameters are illustrated using a case study approach.
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AACN clinical issues · May 2003
ReviewSublingual capnometry: an alternative to gastric tonometry for the management of shock resuscitation.
Normal vital signs do not reflect the physiologic aberrations after blood loss. Recognition of hypoperfusion during resuscitation can avoid the development of multiple organ failure. ⋯ Gastric tonometry can be quite helpful in the intensive care unit in identifying gastric hypoperfusion, but has considerable drawbacks. The ability to monitor P(SI)CO(2) via sublingual capnometers overcomes some limitations of gastric tonometry and may be a valuable aid in the prehospital phase, the emergency department, and the intensive care unit in identifying end points of resuscitation.
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AACN clinical issues · May 2003
ReviewDoppler-based hemodynamic monitoring: a minimally invasive alternative.
Doppler-based hemodynamic assessment affords a magnitude of diagnostic applications including evaluation of blood flow from the left ventricle. Doppler echocardiography, in the form of transthoracic and transesophageal echocardiography, allows for intermittent evaluation of hemodynamic information including aortic blood flow, global and regional wall motion, and valvular integrity. In the hands of a skilled operator, transthoracic and transesophageal echocardiography provides reliable cardiac output determinations. ⋯ In contrast, esophageal Doppler monitoring, a minimally invasive hemodynamic assessment tool, provides the ability for ongoing real-time hemodynamic assessment of the critically ill or compromised patient. This simple-to-use technology requires that a probe, similar in size and shape to a gastric tube, be inserted into the esophagus to obtain measurement of blood flow in the descending aorta. Hemodynamic variables such as cardiac output, preload, afterload, and contractility are measured or derived from the esophageal Doppler monitoring waveform.
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AACN clinical issues · May 2003
ReviewRegional carbon dioxide monitoring: a different look at tissue perfusion.
Adequate tissue oxygenation is one of the main therapeutic goals for the critically ill patient. Until recently, the perfusion status of the critically ill and injured has been assessed by global indices such as blood pressure, heart rate, and urine output. However, these global parameters are inadequate in that they fail to demonstrate the actual perfusion status of a patient. ⋯ Because this region shows early signs of hypoperfusion and hypoxia, its monitoring provides for more effective and complete resuscitation. To that end, gastric tonometry offers a noninvasive means by which early symptoms of low flow can be determined, allowing for optimization of tissue perfusion and patient outcome. The most proximal segment of the gastrointestinal tract offers promising information regarding tissue perfusion with the use of sublingual capnography.