from VM Dept of Anesthesiology, 2007rev 1612 D McMahon.ppt

1、from VM Dept of Anesthesiology, 2007 rev 1/6/12 D McMahon,ASA Standards for Basic Anesthesia Monitoring,The primary goal of anesthesia is to keep the patient as safe as possible in the perioperative period. Careful monitoring of the patient during and after surgery allows the anesthesiologist to ide

2、ntify problems early, when they can still be corrected.,Basic Anesthetic Monitoring,Some of the physiologic disturbances that occur in the perioperative period include, but are not limited to: apnea, respiratory depression, airway obstruction, cardiac depression, hypertension, hypotension, hypervole

3、mia, hypovolemia, arrhythmias, blood loss, fluid shifts, weakness, bradycardia, tachycardia, hyperthermia, and hypothermia. Basic monitoring includes ongoing evaluation of the major body systems.,Guidelines specify what is usually expected, and standards specify what is always expected. The most wid

4、ely accepted current anesthesia monitoring standards are those published by the American Society of Anesthesiologists (ASA). Monitoring standards are not law except in two states, but for all practical purposes they might as well be. Failure to follow nationally published standards sets the practiti

5、oner up for credentialing problems and lawsuits. The ASA standards were initially published in 1986, and were most recently updated in 2006. Copies of the ASA standards for monitoring are available from the ASA.,Standards of Care,The ASA Standards for Basic Anesthetic Monitoring,Standard I states th

6、at a qualified anesthesia provider will be present with the patient throughout the anesthetic. Standard II states that the patients oxygenation, ventilation, circulation, and temperature will be continually monitored. Oxygenation: Inspired oxygen. Hemoglobin saturation with a pulse oximeter and obse

7、rvation of skin color. Ventilation: Capnography. Tracheal intubation must be verified clinically and by detection of exhaled CO2. Mechanical ventilation must be monitored with an audible disconnect monitor. Circulation: ECG monitoring, blood pressure measurement at least every five minutes, and cont

8、inuous monitoring of peripheral circulation by palpation, ausculation, plethysmography, or arterial pressure. Temperature: Thermometry if changes are anticipated, intended, or suspected.,Circulatory Monitoring: ECG and Blood Pressure,Capnography,The most common method of exhaled CO2 measurement is s

9、idestream infrared (IR) capnography. Gas from the circuit is drawn into an infrared measurement chamber. CO2, N2O, H20, and inhaled anesthetic agents all absorb infrared light, but at slightly different frequencies. Newer monitors have precise light sources and filters that specifically measure the

10、individual gases. These monitors provide breath-by-breath gas analysis. Problems with IR capnographs are that moisture can cause blockage of the gas path, and that they cant measure oxygen or nitrogen. Other methods of measuring exhaled gases include RAMAN scattering and mass spectrometry. These sys

11、tems measure oxygen and nitrogen directly, as well as carbon dioxide. They are, however, more expensive and more complicated devices,Ventilation Monitors,Current anesthesia machines have ventilator disconnect alarms and built-in spirometers. The spirometers have high and low limit alarm settings. Co

12、ntinuous measurement of exhaled tidal volume can detect circuit leaks and hypoventilation. The spirometers on the anesthesia machines may give false readings if moisture blocks the innerworkings. Current anesthesia machines also have overpressure alarms and overpressure pop-off valves. Patient injur

13、y can occur before these high pressure alarms are triggered,Temperature Monitors,Monitoring of skin temperature is nearly useless. Upper esophageal and nasopharyngeal temperature are affected by airway temperature. Lower esophageal temperature is normally a good reflection of core or blood temperatu

14、re. Tympanic membrane temperature is also a good indication of core temperature but it is not practical in the operating room environment.,Peripheral Nerve Stimulators,Peripheral nerve stimulation (PNS) monitoring is not required by the ASA standards. However, it is an important safety monitor in patients who a receiving neuromuscular blocking drugs. Train-of-four monitoring assesses the level of nondepolarizer blockade and double-burst stimulation assesses return of strength at the end of the case. Clinical monitoring