Patient Monitoring Patient monitoring and the equipment to support it are vital to caring for patients in operating rooms, intensive care units,emergency departments, and in acute care settings
:Patient Monitoring divided into• Non Instrumental: clinical observation(“look, listen, feel”)Visual and auditory surveillance is central to patient monitoring, and involves many dimensions:• Observing the patient’s color, respiratory pattern, accessory muscle use, and looking for movements, grimaces or unsafe patient positioning
• Observing the patient’s clinical data on intraoperative monitors• Observing bleeding and coagulation at the surgical site (e.g., are the surgeons using many sponges or are they doing a lot of suctioning?)• Monitoring the functioning of all lines to ensure that IV catheters have not infiltrated• Conducting an anesthesia machine and workspace checkout
Instrumental patient monitoring• Electrocardiogram (Provides information about rate, rhythm, ischemia (ST Segments))• Blood pressure (manual, automatic, arterial catheter)• Pulse oximeter (usually on fingertip or ear lobe)• Capnograph (especially in patients with an LMA or ETT)• Oxygen analyzer (part of anesthesia machine)• Anesthetic agent concentration analyzer
7. Temperature (usually esophageal or axillary)8. Precordial or esophageal stethoscope (Listen to heart sounds, breath sounds)9. Gas flows/ spirometry (part of anesthesia machine)10. Airway pressure monitor (part of anesthesia machine)11. Airway disconnect alarm (part of anesthesia machine)12. Peripheral nerve stimulator (where appropriate)13. Urometer (measure urine output where appropriate)
Electrocardiogram ECGThis provides the clinician with three types of information: (1) heart rate, (2) cardiac rhythm (3) information about possible myocardial ischemia (via ST segment analysis) In addition, ECG monitoring can help assess the function of a cardiac pacemakerThe most common electrocardiographic system used during anesthesia is a 5-electrode lead system. This arrangement allows for the recording of any of the six limb leads plus a single precordial (V) lead
Blood PressureMeasurement of arterial blood pressure is an important indicator of the adequacy of circulation Systemic blood pressure monitoring is commonly performed indirectly using extremity- encircling cuffs or directly by inserting a catheter into an artery and transducing the arterial pressure trace.Variety of techniques available for measuring changes in systolic, diastolic, and mean arterial pressure (MAP).
Indirect Measurement of Arterial Blood PressureThe simplest method of blood pressure determination estimates systolic blood pressure by palpating the return of the arterial pulse while an occluding cuff is deflated. Modifications of this technique include the observance of the return of Doppler sounds, the transduced arterial pressure trace, or a photoplethysmographic pulse wave as produced by a pulse oximeter.
• Auscultation of the Korotkoff sounds permit estimation of both systolic (SP) and diastolic (DP)• blood pressures. MAP can be calculated using an estimating equation (MAP = DP + 1/3 [SP-DP]).
• The American Heart Association recommends that the bladder width for indirect blood pressure monitoring should approximate 40% of the circumference of the extremity.• Bladder length should be sufficient to encircle at least 60% of the extremity.• Falsely high estimates result when cuffs are too small, when cuffs are applied too loosely, or when the extremity is below heart level.• Falsely low estimates result when cuffs are too large, when the extremity is above heart level, or after quick deflations.
Automated Intermittent TechniqueMany limitations of manual intermittent blood pressure measurement have been overcome by automated NIBP devices, which are now used widely. In addition, automated NIBP devices provide audible alarms and can transfer data to a computerized information system. However, the greatest advantage of automated NIBP devices over manual methods of blood pressure measurement is that they provide frequent, regular blood pressure measurements and free the operator to perform other vital clinical duties.
• In a generic noninvasive oscillometric monitor (noninvasive blood pressure, or NIBP),• Cuff pressure is sensed by a pressure transducer whose output is digitized for processing.• After the cuff is inflated by an air pump, cuff pressure is held constant while oscillations are sampled.
Direct method (intra-arterial pressure(monitoringIntra-arterial pressure monitoring provides an invasive, continuous measure of blood pressure by beat-to-beatreproduction of the arterial pressure waveform
The method requires the insertion of a short parallel-sided cannula into an artery.A continuous flow of either saline or heparinised saline at rates between 1 and 4 ml per hour is used to reduce clot formation in the cannula.The cannula is connected by a short length of narrow-bore, noncompliantplastic tubing containing saline to a pressuretransducer
Indications for Arterial Cannulation1. Continuous, real-time blood pressure monitoring2. Planned pharmacologic or mechanical cardiovascular manipulation3. Repeated blood sampling4. Failure of indirect arterial blood pressure measurement5. Supplementary diagnostic information from the arterial waveform6. Determination of volume responsiveness from systolic pressure or pulse pressure variation