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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