NON-INVASIVE CARDIOVASCULAR MONITORINGweb.med.u-szeged.hu/expsur/rop/angol/AdvMedSkills/PDF/C1-2...
Transcript of NON-INVASIVE CARDIOVASCULAR MONITORINGweb.med.u-szeged.hu/expsur/rop/angol/AdvMedSkills/PDF/C1-2...
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C1-2 MODUL – Non-invasive monitoring;Invasive hemodinamic monitoring
C3-4 MODUL – Laparotomy, enterotomy,Intestinal suture,Diagnostic peritoneal lavage,Chest tube insertion
C5-6 MODUL – Minimal invasive surgery
Institute of Surgical Research„C” Module
Advance Basic Medical Skills
NON-INVASIVE CARDIOVASCULAR
MONITORING
It is the first line in monitoring of sick patients
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Pulse palpating above carotid artery (in pig ordummy);
Pulse rate estimation;
Can estimate systolic blood pressure if can be palpated carotid pulse - then systolic is at least 60 mmHg;
1. Pulse
Parameters of respiration:
• Tidal volume;• Respiration frequency;• Minute ventillation: volume x frequency;• Inspiration/expiration ratio,
2. Respiration and ventilationMechanical ventillation is need if:
• The spontaneous respiration is insufficient;• It is not spontaneous respiration (apnoe);• In case of hypoxaemia or hypercapnia;
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3. Capnography vs Capnometry
Capnography•Measurement and display of both ETCO2 value and capnogram (CO2 waveform)•Measured by a capnograph
Capnometry•Measurement and display of ETCO2 value (no waveform)•Measured by a capnometer
Continuous non-invasive method for measuring arterial oxygen saturationand pulse rate.
Principle of operation:
infrared absorption by oxygenated and de-oxygenated haemoglobin at twodifferent wavelengths.
4. Pulse oximetry
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The variable absorption due to pulse added volume of arterial blood is used to calculate the saturation of arterial blood
Pulse Oximetry
- Minimizes tissue interference byseparating out the pulsatile signal
- Estimates heart rate by measuring cyclicchanges in light transmission
Oxygen Saturation
Definition:
Percentage of hemoglobin saturated with oxygen
•Normal SpO2 is 95-98%
•Suspect cellular perfusion compromise if < 95% SpO2
•Severe cellular perfusion compromise when SpO2 is < 90%
• SpO2 indicates: the oxygen bound to hemoglobin
• PaO2 indicates the oxygen dissolved in the plasma
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Core temperature = temperature of inner organs (surface -4-5 0C, depends on the site)
Depends on:anatomy - rectum: 37.1± 0.4
oral cavity: 36.7± 0.4axillary: 36.5 ± 0.4
coveringwater contentdaytime (higher in the late afternoon)
5. Temperature monitoring
Electronic device: Termistor (tainted metal oxide semiconductors withnegative temperature coefficients) resistance decreaseswith elevated temperature.
A standard ECG waveform
6. Electrocardiography
It provides information on- Heart rate- Atrial, ventriculal rhythm- Status of myocardial oxygenation- Myocardial diseases- Electrolyte disturbance- Serum K+ level affects the ECG in a predictable and dose related manner- Drug toxicity
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7. Blood pressureIndirect or Direct
Manual or Oscillotonometry (‘electric’)• Mercury manometer• Aneroid manometer
Standard - required machinery– Pulse oxymeter – Apparatus to measure blood pressure, either
directly or non invasively – Electrocardiography – Capnography, when endotracheal tubes or
laryngeal masks are inserted– Apparatus to measure temperature
Monitoring guidelines (ASA)
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7. Gastrointestinal tonometry
Tonomitor includes a semi-permeable siliconeballoon for CO2 at the distal end of the catheter.
Indirect Tonometry: the Basics
Catheter is positioned in the stomach and CO2 freelyequilibrates between the gastric mucosa and the balloon.
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pCO2 HCO3
[ ]
pHi= pKD + lg ————————————
0,03 x
Intramucosalis pH (pHi) determination
From arterial blood sample:HCO3 level is determinated by blood pH and pCO2;
Saline sample from Tonomitor catheter: mucosal pCO2 determination;
CO2-gap
CO2-gap=pACO2 – pgCO2
pACO2= systemic arterial pCO2
pgCOpgCO22= = locallocal tissuetissue pCOpCO2 2 ((signedsigned byby tonomitortonomitor))
Gasztrotonometry → indirect monitoring ofmucosal microcirculation;
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2,5 ml
Sigmoid Tonomitor(wih balloon)
Saline
Bicarbonate buffer
Time of equilibration: min. 30 min„Static” device
0,2-0,3 ml
Time of equilibration: 4-6 minDynamic device
Capillar TonomitorConstructed by Boda et. al.
Catheters of gastrotonometry
Changing of intramucosal pH inhemorrhagic shock
Time (min)0 30 60 90 120 150 180 210 240
pHi
6,3
6,6
6,9
7,2
Intestinal pHi Sigmoid TIntestinal pHi Cap.TEsophageal pHi Cap.T
Hemorrhagic shock
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INVASIVE HEMODYNAMIC
MONITORING
1. Measurement of central venous pressure
Place of puncture: 1. Internal jugular vein; 2. V. subclaviaNormal value of CVP: 2-6 mmHg;
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1. Central vein catheterization
(Surgical Team 1.);
• Surgical exploration of left side jugular vein;
• Percutaneos puncture of jugular vein with asepticSeldinger technique.
• Fix the cannula securely and connect it to the pressure measurement system;
The Seldinger technique for central venous catheterization
1. Introduce a Braunüle into a periferal vein
3. Insert a flexible guide-wire to the central vein
5. Insert – then remove a dilator cannula
6. Insert the central venous cannula
2. Remove the needle
4. Remove the Braunüle cannula
7. Remove of guide-wire
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Axillary (A)Brachial (B)Femoral (F)Radial (R), long catheter
A
B
F
R
2. Measurement of arterial pressure inclinical practice
Arterial pressure transducer
Places of catheterization
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2. Catheterization of femoral artery(Surgical Team 2.)
• Skin incision on the ingvinal area;• Cutting of connective tissue by diatermy;• Abdominal wall is retracted;• Carefull, blunt disection of femoral artery (by
using dressing forceps only);• Catheterization with a termistor sensor supplied
Swan-Ganz catheter; • Fix the catheter securely and connect it to the
pressure sensor;
Monitor
Arterial thermodilution catheter
Injectate temperature sensor
Disposable pressure transducer
Central venous catheter Injectate temperaturesensor housing
3. Cardiac output measurement with a transpulmonary thermodilution method
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Cold salinebolusinjection
Termistorcatheterin aorta
Left HeartRight heart
RA PBVEVLW
LA LV
EVLW
RV
Scheme of transpulmonary thermodilutionmethod
A known volume of cold (2,5-5-10-20 ml; at least 10°C lower than blood temperature) solution is injected intravenously, as fast as possible.
The effect of thermal bolus injected into the central vein is registered by a thermistor catheter positioned in the femoral artery.
The temperature change recorded downstream is dependent on the flow and on the volume through which the cold indicator has passed. As a result, a thermodilution curve can be obtained.
The cardiac output is calculated from the area ofthermodilution curve.
Measurement of Cardiac Output (CO)
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Calculated hemodynamicparameters from arterial
pressure and cardiac output:
Cardiac index = CO/body area (ml/min/m2)
Stroke volume = CO/heart rate (ml)
Peripheral vascular resistance =
= (Mean arterial pressure-CVP)/CO
Goal: to determine the blood gas state of the patient
• O2 uptake
• CO2 excretion in the lung• blood pH• HCO3
- the role of kidneysSteps:
Sample taken;Measurement by blood gas analyser;Data interpreting;
4. Arterial and venous blood sampletaken and blood gas analysis
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1. Sack about 4-times of catheter volum blood beforesample taking (this vill be discarded) by a 5 ml syringe;
2.Fill with heparine (inhibition of blood coagulation) the conus of a 2 ml syringe; (heparine content: 50-100 U/ml blood)!
3.Sack about 1 ml blood into the heparine filledsyringe;
4.Remove air bubble from the syringe;
5.Closed the syringe with cap;
6.Rinse about 5 ml saline the catheter;
Blood sample taken
AVL Compact 2(AVL Medical Instruments)
Sample detecting system:• sense an air bubble;• sense the quantity of sample;
Minimal samle volume: 55 µl
Measurement time: 20 sec
Measurement by blood gas analyser
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Measured parameters:pO2, pCO2, pH
Calculated parametersBE, HCO3
-, O2sat, ctO2,
Metabolits:cLactate, cGlucose
Electrolits:cK+, cNa+, cCl-, cCa2+
Blood gas and Acid-Base parameters:
a negative number is a base deficitmmol/l-2, 0, +2base excess
the [HCO3-] after the
sample has beenequilibrated with CO2 at40mmHg (5,3kPa)
mmol/l22 - 24 - 26standard bicarbonate
normal values vary if thePCO2 is abnormalmmol/l22 - 24 - 26HCO3 (actual
bicarbonate)
lower at high altitude, higher if supplementaloxygen
mmHg90 - 100
at sea level, FiO2 = 21%kPa11.9 - 13.2
pO2
mmHg36 - 40 - 44kPa4.8 - 5.3 - 5.9
pCO2
(no units)7.35 - 7.4 - 7.45pHNotesUnitsNormal rangeItem
Blood Gas Normal Values
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Calculated parameters of oxygentransport and uptake by cardiac
output and blood gas data:
• Arterial Oxygen Content = CaO2 Vol%• Venous Oxygen Content = CvO2 Vol%• A-V Content Difference• Oxygen Delivery ml/min• Oxygen Extraction %• Oxygen Consumption
– ml/min – ml/Kg
Which factors determine O2 delivery?Arterial oxygen content (CaO2)
a. Hemoglobine (Hgb)b. Saturation (SO2);Total saturated Hgb delevers 1.38 ml oxygen (per gram)
Arterial Oxygen Content in Vol% (CaO2) = = Hb x 1.34 x (SaO2/100) + (PaO2 x 0.0031
Cardiac Output (CO)
Oxygen delivery (DO2)
DO2 [ml/min]=CO x [(1,38 x Hb x SaO2)+(0,003xpaO2)]
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Oxygen saturation (SO2)
95-100 %70-90 %
Percentage of hemoglobin saturated with oxygen
Body/Organs
Oxygen Consumption (VO2)
If Hgb, CO and A/V saturations are known, VO2 may be calculated without knowing the pO2 values;
Dissolved O2 normally contributes < 0.3 Vol% of the arterial O2 content:
Derived from the Fick equation:this method calculates the arterial and venous oxygen contentdifference and multiplies that value by the CO:
VO2 (ml/min) = (CaO2-CvO2) x CO
VO2 (ml/min)=Hb x 1.34 x [(SaO2-SvO2)/100] x CO
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5. Monitoring of pulmonary circulation
Pulmonary artery
Monitoring of Pulmonary Artery Pressure (PAP) and Cardiac Output by Swan Ganz catheter
Yellow: PA pressureBlue: for CVP and injectionWhite: termistor cabelRed: catheter balloon
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Positioning of Swan Ganz catheter
Pulmonary artery and wedge pressures
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Cardiac output measurement with Swan Ganz catheter in clinical practice (thermodilution)
Injector branch of catheter
Thermal bolus sensingthermistor branch
Pressure transducer
Internal reference thermistor sensorfor cold saline injecting
Inflatable branch of catheter
Computermonitor
Tb injection
t
5. Monitoring of pulmonary circulation
1. Explore the right side jugular vein (Surgical team 1.);
2. Catheterisation with Swan-Ganz catheter;
3. Introduce Swan-Ganz catheter into the arteria pulmonalisby right of monitoring of continous blood pressure signaland helping of the inflatable baloon at the tip of catheter;
4. Pulmonary artery pressure, pulmonary capillar wedgepressure and cardiac output can be measuredsimultenaously;
Introduce a Swan-Ganz catheter into the arteria pulmonalisfrom the jugular vein and through the right heart:
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Transonic animal research flowmeter consists of a bench-top electronic flow detection unit with enhanced frequency resolution and volume flow sensing probes.
The ultrasonic transducer within the flow sensor body transmits a minimum level of ultrasound through a rectangular sensing window and sense volume flow of all liquid passing through this window.
6. Blood flow measurementon carotis artery
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Acid-base Balance – the Basics
Among the buffer system of the human body bicarbonateregulates the pH of the whole system, because it acts on twopoints:
HCO3- through kidneys
CO2 through the lungs: H+ + HCO3- <=> H2CO3 <=> H2O + O2
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PaCO2 – Partial pressure of CO2 in the arterial blood.PaO2 – Partial pressure of O2 in the arterial blood.Oxygen is carried in the blood in 2 forms:Dissolved O2 (~2-3% of total O2 content)O2 bound to hemoglobin (~97-98% of total O2 content)Total O2 content of blood (Ca O2) = Dissolved O2 + O2
bound to hemoglobinBackground•Oxygen is exchanged by diffusion from higher concentrations to lower concentrations•Most of the oxygen in the arterial blood is carried bound to hemoglobin:
–97% of total oxygen is normally bound to hemoglobin–3% of total oxygen is dissolved in the plasma
Gas Exchange