240- PROBLEM SET INSERTION OF SWAN-GANZ 50 kg Pig Rt Jugular 0 cm Rt Atrium 10 cm Rt ventricle 15 cm Wedge 20-25 cm SYSTEMIC VASCULAR RESISTANCE Blood pressure = f(cardiac output and peripheral resistance) (CO) I R (Body) E 1 E 0 (Heart) I = Voltage Drop (E 1- E 0) / Resistance 1
SYSTEMIC VASCULAR RESISTANCE Increased SVR Viscosity Polycythemia Hypothermia Arterial Tone Sympathetic activation Pain Hypoxia Hypercarbia Acidosis Drugs Catecholamines Vasoconstrictors Patient disease Hypertension Pheochromocytoma Decreased SVR Viscosity Hemodilution Arterial Tone Sympatholysis Deep anesthesia Spinal/Epidural anes. Drugs Anesthetics Vasodilators SNP, NTG Ca blockers AII blockers ACE inhibitors Patient disease Sepsis Anaphylaxis SYSTEMIC VASCULAR RESISTANCE CO = MAP - CVP SVR = MAP - CVP SVR CO x 80 = dynes-sec/cm5 CO = cardiac output: (5L/min) MAP=mean arterial pressure: Arterial line (100mmHg) CVP = central venous pressure: Swan Ganz tip prior to RV insertion (5 mm/hg) SVR = 100-5 x 80 = 1520 dynes-cm 5 5 PULMONARY VASCULAR RESISTANCE Blood pressure = f(cardiac output and pulmonary resistance) Lung (CO) E 1 E 0 I R I = Voltage Drop (E 1- E 0) / Resistance 2
PULMONARY VASCULAR RESISTANCE Increased PVR Viscosity Polycythemia Hypothermia Arterial Tone Sympathetic activation Pain Hypoxia Hypercarbia Acidosis Drugs Catecholamines Vasoconstrictors Patient disease Pulmonary embolism COPD, emphysema Anaphylaxis Heart failure Decreased PVR Viscosity Hemodilution Arterial Tone Drugs Oxygen Nitric oxide Hyperventilation Alkalosis It is difficult to reduce PVR in the clinical setting PULMONARY VASCULAR RESISTANCE CO = MPA - PCWP PVR = MPA - PCWP PVR CO x 80 = dynes-sec/cm5 CO = cardiac output: SG-thermal dilution (5 L/min) PCWP = pulmonary capillary wedge pressure: (7 mmhg) MPA = pulmonary art pressure: unwedged. (10 mm/hg) PVR = 10-7 x 80 = 48 dynes-cm 5 5 Fick Equation O 2 consumption = CO * [CaO 2 - CvO 2 ] CvO 2 CaO 2 = 15.5 ml / dl CvO 2 = 10.2 ml / dl CO = 3 l / min CaO 2 VO 2 = 30 dl / min * [15.5 ml / dl - 10.2 ml / dl] = 159 ml / min 3
Oxygen Content of Blood Blood Gas Analysis Arterial Blood Gas Tensions Bound to hemoglobin 1.39 * Hgb (g/dl) * SpO2 (%) ph normal Dissolved in plasma 0.003 ml/mmhg * PaO2 (mmhg) Hgb = 15 gm/dl SpO2 = 100% PaO2 = 110 mmhg CaO2 = [1.39 * 15 * 100%] + [0.003 * 110] = 21.2 ml / dl FiO2 = 0.3 PiO2 = 224 PaO2 = 177 Slight reduction PaO2 PaCO2 normal Ventilation appropriate Calculated Sigaard-Andersen Nomogram Hemoglobin saturation CaO2 = 1.39 * 10.9 * 99% + 0.003 * 121 = 15.5 ml/dl 4
Venous Blood Gas Tensions ph slightly lower PaCO 2 slightly higher Ventilation appropriate Body metabolism: O2 in (consumption) CO2 out Fick equation: VO2 = (Amt O2 extracted by body) x (Blood delivered) Fick Equation Effect of Cardiac Output O 2 consumption = CO * [CaO 2 - CvO 2 ] FiO 2 = 0.3 PiO 2 = 224 PaO 2 = 177 Slight reduction PaO 2 CaO 2 = 1.39 * 12.9 * 66% + 0.003 * 37 = 11.9 ml / dl 10.2 ml / dl Calculated Sigaard-Andersen Nomogram Hemoglobin saturation Amount of O2 delivered (extracted) Arterial O 2 content - Venous O 2 content Samples Arterial: Arterial line Venous: Pulmonary artery (PA Distal port) Content Bound to hemoglobin: 1.39 * Hgb (g/dl) * SpO 2 (%) Dissolved in plasma: 0.003 ml/mmhg * PaO 2 (mmhg) Amount of Blood delivered: Cardiac output CO = 6 l / min CaO 2 = 15.5 ml / dl CvO 2 = 12.9 ml / dl CaO 2 = 15.5 ml / dl CvO 2 = 10.2 ml / dl CO = 3 l / min CaO 2 = 15.5 ml / dl CO = 1.5 l / min CvO 2 = 4.9 ml / dl 5
15 cm PEEP Positive end tidal expiratory pressure Connect PEEP valve in expiratory air way circuit..equivalent outflow into 15 cm of water EFFECT UPON CARDIAC OUTPUT? Weighted ball Exhaled Gas ACUTE LINKAGE BETWEEN BP AND HR Baroreceptor Reflex BP HR BP HR? IF NOT WHY NOT? 6
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