Institute of Surgical Research C Module Advance Basic Medical Skills

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1 Institute of Surgical Research C Module Advance Basic Medical Skills 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 NON-INVASIVE CARDIOVASCULAR MONITORING It is the first line in monitoring of sick patients

2 1. Pulse Pulse palpating above carotid artery (in pig or dummy); Pulse rate estimation; Can estimate systolic blood pressure if can be palpated carotid pulse - then systolic is at least 60 mmhg; 2. Respiration and ventilation Mechanical ventillation is need if: The spontaneous respiration is insufficient; It is not spontaneous respiration (apnoe); In case of hypoxaemia or hypercapnia; Parameters of respiration: Tidal volume; Respiration frequency; Minute ventillation: volume x frequency; Inspiration/expiration ratio,

3 3. Capnography vs Capnometry Capnography Measurement and display of both ETCO 2 value and capnogram (CO 2 waveform) Measured by a capnograph Capnometry Measurement and display of ETCO 2 value (no waveform) Measured by a capnometer 4. Pulse oximetry Continuous non-invasive method for measuring arterial oxygen saturation and pulse rate. Principle of operation: infrared absorption by oxygenated and de-oxygenated haemoglobin at two different wavelengths.

4 Pulse Oximetry - Minimizes tissue interference by separating out the pulsatile signal - Estimates heart rate by measuring cyclic changes in light transmission The variable absorption due to pulse added volume of arterial blood is used to calculate the saturation of arterial blood Oxygen Saturation Definition: Percentage of hemoglobin saturated with oxygen Normal SpO 2 is 95-98% Suspect cellular perfusion compromise if < 95% SpO 2 Severe cellular perfusion compromise when SpO 2 is < 90% SpO 2 indicates: the oxygen bound to hemoglobin PaO 2 indicates the oxygen dissolved in the plasma

5 5. Temperature monitoring Core temperature = temperature of inner organs (surface C, depends on the site) Depends on: anatomy - rectum: 37.1± 0.4 oral cavity: 36.7± 0.4 axillary: 36.5 ± 0.4 covering water content daytime (higher in the late afternoon) Electronic device: Termistor (tainted metal oxide semiconductors with negative temperature coefficients) resistance decreases with elevated temperature. 6. Electrocardiography A standard ECG waveform 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

6 Indirect or Direct 7. Blood pressure Manual or Oscillotonometry ( electric ) Mercury manometer Aneroid manometer Monitoring guidelines (ASA) 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

7 7. Gastrointestinal tonometry Tonomitor includes a semi-permeable silicone balloon for CO 2 at the distal end of the catheter. Indirect Tonometry: the Basics Catheter is positioned in the stomach and CO 2 freely equilibrates between the gastric mucosa and the balloon.

8 Intramucosalis ph (phi) determination pco 2 HCO 3 From arterial blood sample: HCO 3 level is determinated by blood ph and pco 2 ; Saline sample from Tonomitor catheter: mucosal pco 2 determination; [ ] phi= pk D + lg 0,03 x CO 2 -gap CO 2 -gap=paco 2 pgco 2 paco 2 = systemic arterial pco 2 pgco 2 = local tissue pco 2 (signed by tonomitor) Gasztrotonometry indirect monitoring of mucosal microcirculation;

9 Catheters of gastrotonometry Bicarbonate buffer 0,2-0,3 ml 2,5 ml Saline Sigmoid Tonomitor (wih balloon) Time of equilibration: min. 30 min Static device Capillar Tonomitor Constructed by Boda et. al. Time of equilibration: 4-6 min Dynamic device phi Changing of intramucosal ph in hemorrhagic shock 7,2 6,9 6,6 * * * * * 6,3 * Hemorrhagic shock Time (min) Intestinal phi Sigmoid T Intestinal phi Cap.T Esophageal phi Cap.T

10 INVASIVE HEMODYNAMIC MONITORING 1. Measurement of central venous pressure Place of puncture: 1. Internal jugular vein; 2. V. subclavia Normal value of CVP: 2-6 mmhg;

11 1. Central vein catheterization (Surgical Team 1.); Surgical exploration of left side jugular vein; Percutaneos puncture of jugular vein with aseptic Seldinger 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 2. Remove the needle 3. Insert a flexible guide-wire to the central vein 4. Remove the Braunüle cannula 5. Insert then remove a dilator cannula 6. Insert the central venous cannula 7. Remove of guide-wire

12 2. Measurement of arterial pressure in clinical practice Places of catheterization Axillary (A) Brachial (B) Femoral (F) Radial (R), long catheter B A R F Arterial pressure transducer

13 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; 3. Cardiac output measurement with a transpulmonary thermodilution method Central venous catheter Injectate temperature sensor housing Monitor Injectate temperature sensor Disposable pressure transducer Arterial thermodilution catheter

14 Scheme of transpulmonary thermodilution method Cold saline bolus injection Termistor catheter in aorta Right heart RA RV EVLW PBV EVLW LA Left Heart LV Measurement of Cardiac Output (CO) A known volume of cold (2, 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 of thermodilution curve.

15 Calculated hemodynamic parameters from arterial pressure and cardiac output: Cardiac index = CO/body area (ml/min/m 2 ) Stroke volume = CO/heart rate (ml) Peripheral vascular resistance = = (Mean arterial pressure-cvp)/co 4. Arterial and venous blood sample taken and blood gas analysis Goal: to determine the blood gas state of the patient O 2 uptake Steps: CO 2 excretion in the lung blood ph HCO - 3 theroleofkidneys Sample taken; Measurement by blood gas analyser; Data interpreting;

16 Blood sample taken 1. Sack about 4-times of catheter volum blood before sample 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: U/ml blood)! 3. Sack about 1 ml blood into the heparine filled syringe; 4. Remove air bubble from the syringe; 5. Closed the syringe with cap; 6. Rinse about 5 ml saline the catheter; Measurement by blood gas analyser Sample detecting system: sense an air bubble; sense the quantity of sample; Minimal samle volume: 55 µl Measurement time: 20 sec AVL Compact 2 (AVL Medical Instruments)

17 Blood gas and Acid-Base parameters: Measured parameters: po 2, pco 2, ph Calculated parameters BE, HCO 3-, O 2 sat, cto 2, Metabolits: clactate, cglucose Electrolits: ck +, cna +, ccl -, cca 2+ Blood Gas Normal Values Item ph pco 2 po 2 HCO 3 (actual bicarbonate) standard bicarbonate base excess Normal range , 0, +2 Units kpa mmhg kpa mmhg mmol/l mmol/l mmol/l Notes (no units) at sea level, FiO 2 = 21% lower at high altitude, higher if supplemental oxygen normal values vary if the PCO 2 is abnormal the [HCO 3- ] after the sample has been equilibrated with CO 2 at 40mmHg (5,3kPa) a negative number is a base deficit

18 Calculated parameters of oxygen transport and uptake by cardiac output and blood gas data: Arterial Oxygen Content = CaO 2 Vol% Venous Oxygen Content = CvO 2 Vol% A-V Content Difference Oxygen Delivery ml/min Oxygen Extraction % Oxygen Consumption ml/min ml/kg Oxygen delivery (DO2) Which factors determine O 2 delivery? Arterial oxygen content (CaO 2 ) a. Hemoglobine (Hgb) b. Saturation (SO 2 ); Total saturated Hgb delevers 1.38 ml oxygen (per gram) Arterial Oxygen Content in Vol% (CaO 2 ) = = Hb x 1.34 x (SaO 2 /100) + (PaO 2 x Cardiac Output (CO) DO 2 [ml/min]=co x [(1,38 x Hb x SaO 2 )+(0,003xpaO 2 )]

19 Oxygen saturation (SO 2 ) Percentage of hemoglobin saturated with oxygen % % Body/Organs Oxygen Consumption (VO 2 ) Derived from the Fick equation: this method calculates the arterial and venous oxygen content difference and multiplies that value by the CO: VO 2 (ml/min) = (CaO 2 -CvO 2 ) x CO If Hgb, CO and A/V saturations are known, VO 2 may be calculated without knowing the po 2 values; Dissolved O 2 normally contributes < 0.3 Vol% of the arterial O 2 content: VO 2 (ml/min)=hb x 1.34 x [(SaO 2 -SvO 2 )/100] x CO

20 5. Monitoring of pulmonary circulation Pulmonary artery Monitoring of Pulmonary Artery Pressure (PAP) and Cardiac Output by Swan Ganz catheter Yellow: PA pressure Blue: for CVP and injection White: termistor cabel Red: catheter balloon

21 Positioning of Swan Ganz catheter Pulmonary artery and wedge pressures

22 Cardiac output measurement with Swan Ganz catheter in clinical practice (thermodilution) Inflatable branch of catheter Internal reference thermistor sensor for cold saline injecting Injector branch of catheter Pressure transducer Computer monitor Thermal bolus sensing thermistor branch T b injection t 5. Monitoring of pulmonary circulation Introduce a Swan-Ganz catheter into the arteria pulmonalis from the jugular vein and through the right heart: 1. Explore the right side jugular vein (Surgical team 1.); 2. Catheterisation with Swan-Ganz catheter; 3. Introduce Swan-Ganz catheter into the arteria pulmonalis by right of monitoring of continous blood pressure signal and helping of the inflatable baloon at the tip of catheter; 4. Pulmonary artery pressure, pulmonary capillar wedge pressure and cardiac output can be measured simultenaously;

23 6. Blood flow measurement on carotis artery 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. Acid-base Balance the Basics Among the buffer system of the human body bicarbonate regulates the ph of the whole system, because it acts on two points:. HCO 3- through kidneys CO 2 through the lungs: H + + HCO 3- <=> H 2 CO 3 <=> H 2 O + O 2

24 Gas Exchange P a CO 2 Partial pressure of CO 2 in the arterial blood. P a O 2 Partial pressure of O 2 in the arterial blood. Oxygen is carried in the blood in 2 forms: Dissolved O 2 (~2-3% of total O 2 content) O 2 bound to hemoglobin (~97-98% of total O 2 content) Total O 2 content of blood (Ca O 2 ) = Dissolved O 2 + O 2 bound to hemoglobin Background 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