noninvasive blood pressure monitoring

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Non Invasive Blood Pressure

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DR.RAKESH CHINTALAPUDI PRESENTED BY : MD. D.A., e mail id : rakesh1959@gmail.com

INTRODUCTION: 

INTRODUCTION Frequent BP monitoring Drug Titration Fluid Management Impending danger to patient SAFETY OF PATIENT I C U IC C U P I C U S I C U I R C U INTRMD. ICU POSTOP O T

INTERMITTENT BLOOD PRESSURE MONITORS: 

INTERMITTENT BLOOD PRESSURE MONITORS INTERMITTENT CONTINUOUS VASOTRAC T-LINE TENSYMETER

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PALPATION AUSCULTATION DOPPLER PROBE OSCILLOMETRY PLETHYSMOGRAPHY ARTERIAL TONOMETRY A R T E R Y

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DOPPLER PROBE PLETHYSMOGRAPHY ARTER. TONOMETRY

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ARTERIAL TONOMETRY

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CONTINUOUS NONINVASIVE BLOODPRESSURE INSTRUMENTS

Vasotrac : 

Vasotrac

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Wrist Module Connecting cable Monitor / Display Pressure sensing mechanism applies variable pressures pressure - counter pressure method Wave form analysis gives SP DP MAP. Range 40 to 240 Accurate with arrhythmias even V A S O T R A C

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Vasotrac does not provide continuous BP measurement, it provides readings 3 to 4 times per minute than the Intermittent method.

T-line Tensymeter: 

T-line Tensymeter

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Utilizes arterial Tonometry. Peripheral artery is slightly compressed pulse wave is picked up by the transducer placed over it. Thee components 1.disposable wrist splint 2.disposable radial artery sensor 3.reusable bracelet. T- LINE TENSYMETER

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First wrist restraint is applied Sensor is aligned to pulsation, then bracelet is applied. The pulsations are converted to waveform This provides continuous beat to beat NIBP measurements The B P closely agreed with measurements done via Invasive methods on opposite pulse.

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PLETHYSMOGRAPHY

PLETHYSMOGRAPHY: 

PLETHYSMOGRAPHY Light emitting diode – photoelectric cell Detects changes in finger volume Solenoid controlled air pump rapidly modulates cuff pressures which are displayed as beat to beat tracings.

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Although the pressures are intra-arterial determinations, Plethysmography has proved unreliable in patients with poor peripheral perfusion, hypothermia, therefore not recommended for routine clinical use.

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DOPPLER PROBE

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DOPPLER’S EFFECT is shift in the frequency of sound waves when their source moves relative to the observer. The pitch of train’s whistle increases as a train approaches and decreases as it departs. As RBC moves in artery Doppler frequency shift will be detected by the probe.

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The difference between transmitted and received frequency is represented by swishing sound, which indicates blood flow. Air between probe and skin can interfere with readings, thin jelly is used for better results. Only Systolic pressures can be recorded.

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OSCILLOMETRY

STANDARDS: 

STANDARDS AMERICAN STANDARDS 2002 : BP determined by the device be equivalent to those obtained by intra-arterial technique by trained person. INTERNATIONAL STANDARDS 1999 : Equipment specified for adults 300 mm Hg Equipment specified for neonates 150 mmHg

Operating Principles: 

Operating Principles Microprocessor controls the sequence of inflation and deflation of the cuff. The cuff is inflated to a pressure above the previous systolic pressure; it is then deflated incrementally. A transducer senses the pressure changes, which are processed by the microprocessor. This has an accuracy of +/- 2%. The mean arterial pressure (MAP) corresponds to the maximum oscillation at the lowest cuff pressure. The systolic pressure corresponds to the onset of rapidly Increasing oscillations.

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Diastolic pressure corresponds to the onset of rapidly decreasing oscillations. It is also calculated from the systolic and, MAP. (MAP= diastolic + one-third pulse pressure)

Equipment: 

Equipment Inflatable cuff Pressure tubings Cuff inflation deflation mechanism Sensing mechanism Timing Circuitry Control Circuitry Alarms

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Inflatable Cuff Cuff Inflation Deflation mechanism : Pressure Tubing : Sensing Mechanism

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Timing Circuitry : Control Circuitry : Alarms :

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American Heart Association Recommended Bladder Dimensions for Blood Pressure Cuffs According to Arm Circumference (Cuff Width = 40% of Arm Circumference) Upper Arm Circumference Cuff Name Bladder Width (cm) 5 – 7.5 Newborn 3 7.5 – 13 Infant 5 31 –20 Child 8 24 – 32 Adult 13 32 –42 Wide/large adult 17 42 – 50 Thigh 20

Sources of error : 

Sources of error If the cuff is too small, the blood pressure over-reads. Similarly, if too large then the blood pressure under-reads (greatest error is seen with an undersized cuff). Systolic pressure over-reads at low pressures (<60 mmHg) and under-reads at high systolic pressures. Arrhythmias such as atrial fibrillation affect accuracy. External pressure on the cuff (e.g. the surgeon!) can cause inaccuracies.

ACCURACY: 

ACCURACY FACTORS AFFECTING CUFF/ARM RELATIONSHIP SITE ARM POSITION BP DETERMINATIONS IMPROPER CALIBRATION AND MAINTENANCE : ARRHYTHMIAS

Complications : 

Complications Damage to Underlying Tissues : Petechiae, erythema, edema, thrombophlebitis, skin avulsion- predisposing with drugs like Neuropathies : Median Ulnar, Radial nerves – resolves spontaneously predisposing – excessive movements Mechanical Problems : failure or NIBP readings may cause serious problems—leaking cuff, hose, connectors Artifacts : intrinsic , extrinsic motion artifacts Air Embolism : Line used to inflate the cuff is connected to an intravenous line, a serious air embolus can result.

Advantages : 

Advantages Automaticity Simplicity Reliability Non invasiveness Usefulness Versatility Monitor integrity

Disadvantages : 

Disadvantages Unsuitable situations Patient discomfort Non continuous measurements Clinical Limitations

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Thank You