Download Physiologic Monitoring of the Surgical Patient

Basic Science Conference
1/26/2010
Background
 Latin word monere, which means “to warn, or advise,”
is the origin for the English word monitor.
 Patients undergo monitoring to detect pathologic
variations in physiologic parameters, in order to give
us advance warning of deterioration of one or more
organ systems.
 GOAL: Use the information to make a timely
intervention.
 Monitoring also used to guide resuscitation and titrate
medications.
Background (cont.)
 The ultimate goal of hemodynamic monitoring is to
ensure that the flow of oxygenated blood through the
microcirculation is sufficient to support aerobic
metabolism at the cellular level.
 This involves multiple inputs.
 Oxygen delivery
 CO
 Hgb
 O2 sat
 PAO2
Arterial Blood Pressure
 The pressure exerted by blood in the systemic arterial
system.
 Hypotension = Shock ?
 MAP = CO x SVR
 How do we measure blood pressure?
 Non-invasive (cuff)
 Invasive
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Risks and benefits
Noninvasive
 Manual and automated means, both of which use a
cuff. The width of the cuff should be about 40% of the
circumference.
 Korotkoff sounds
 Systolic- tapping sounds first audible
 Diastolic- audible pulsations disappear
 Dyna-map
Invasive
 Fluid-filled tubing to connect an intra-arterial catheter
to external strain-gauge transducer which is
transduced as a continuous waveform.
 Underdamped –systolic overestimated and diastolic
underestimated
 Overdamped- systolic underestimated and diastolic
overestimated
 Use Mean Arterial Pressure
 Systolic pressure higher, diastolic pressure lower in
the radial artery compared to the aorta
Invasive Complications
 Thrombosis (Allen test)
 Air Embolism
 Infection
EKG monitoring
 Continuous monitoring with three lead EKG
 Immediate alarm with arrhythmias
 Can detect ST elevation
 No substitute for 12 lead EKG
Cardiac output
 Determinants of Cardiac Performance
 Preload - EDV
 Afterload-SVR
 Contractility- dependent on preload and afterload
Pulmonary artery catheter
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PAC has four channels
Balloon (1.5cc)
CVP, PA
Insertion
Waveforms
Distance
 45 cm RSCV
 50cm RIJ
 55cm LSC
 60cm LIJ
Approximate Normal Ranges for Selected Hemodynamic
Parameters in Adults
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CVP 0–6 mmHg
Right ventricular systolic pressure 20–30 mmHg
Right ventricular diastolic pressure 0–6 mmHg
PAOP 6–12 mmHg
Systolic arterial pressure 100–130 mmHg
Diastolic arterial pressure 60–90 mmHg
MAP 75–100 mmHg
QT 4–6 L/min
QT* 2.5–3.5 L·min–1·m–2
SV 40–80 mL
SVR 800–1400 dyne·sec·cm–5
SVRI 1500–2400 dyne·sec·cm–5·m–2
PVR 100–150 dyne·sec·cm–5
PVRI 200–400 dyne·sec·cm–5·m–2
Hemodynamic measurements
 Cardiac output by thermodilution
 Mixed venous oximetry
 RV ejection fraction
Types of Shock
 Hemorrhagic
 Septic
 Cardiogenic
 Neurogenic
 Hypo adrenal
Risks and benefits of PACs
 Many studies show no mortality difference with PAC
use and more complications related to the catheter or
its placement.
 Alternatives
 Doppler Ultrasonography
 Impedance cardiography
 Pulse contour analysis
 TEE
Respiratory monitoring
 The ability to monitor various parameters of
respiratory function is of utmost importance is
critically ill patients.
 Arterial blood gases
 Peak and plateau airway pressure
 Pulse oximetry
 CO2 monitoring
ABG
 O2 (PEEP, FIO2)
 CO2 (RR, TV)
 O2 sat
 HCO3
 BE/BD
Airway Pressures
 Increased pressure = decreased compliance
 Hemo/pneumothorax
 Atelectasis
 Pulmonary edema
 ARDS
 Abdominal distension
 Barotrauma
Renal monitoring
 Urine output
 Bladder pressure
Neurologic monitoring
 Intracranial pressure
 CPP= MAP- ICP
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CPP>60
 Allows monitoring and drainage
 Strategies to decrease ICP
 Transcranial doppler ultrasonography
 EEG
 Brain tissue oxygen tension
Conclusions
 Physiologic monitoring provides us with a multitude
of information.
 Determining what information is beneficial and using
this to positively affect the outcome of the patient is
the key.
All of the following are most often associated with a
decrease in SVO2 except:
 Myocardial infarction
 Cardiac tamponade
 Hemorrhagic shock
 Septic shock
You place a swan ganz catheter in a 709kg adult male through
the left subclavian vein and get a wedge pressure. The
approximate distance into the patient should be:
 45cm
 50cm
 55cm
 60cm
While trying to treat a patient with severe ARDS, you start to
increase the PEEP to improve oxygenation. After doing this, you
notice a decrease in urine output. The mechanism of decreased
urine output with increased PEEP is:
 Compartment syndrome
 Decreased cardiac output
 Reduced oxygenation
 Retained CO2
A patient stops making urine after surgery. All of te following
values are consistent with pre-renal renal failure except:
 Urine Na 5
 BUN/Cr ratio >35
 FeNA=0.1%
 Urine osmolality 200 mOsm
All of the following concerning pulmonary artery catheters are
true except:
 Excessive PEEP can artificially increase wedge
pressure.
 Excessive PEEP can artificially decrease wedge
pressure.
 Zone III of the lung is the optimal site of placement.
 The balloon should be inflated when advancing the
catheter.
A critical care patient has the following PAC values: CI 1.8, SVR
3000, and a wedge pressure of 5. This is most consistent with:
 Septic shock
 Hypovolemic shock
 Cardiogenic shock
 Neurogenic shock
A critical care patient has the following PAC values: CI 5.0, SVR
500, and a wedge pressure of 7. This is most consistent with:
 Septic shock
 Hypovolemic shock
 Cardiogenic shock
 Neurogenic shock
A critical care patient has the following PAC values: CI 1.8, SVR
3000, and a wedge pressure of 28. This is most consistent with:
 Septic shock
 Hypovolemic shock
 Cardiogenic shock
 Neurogenic shock
A critical care patient has the following PAC values: CI 2.0, SVR
500, and a wedge pressure of 5. This is most consistent with:
 Septic shock
 Hypovolemic shock
 Cardiogenic shock
 Neurogenic shock
A patient with ARDS following an inhalation injury has an
oxygenation saturation of 90% on 90% FiO2 with an SVO2 of 55.
The patient’s ABG is pH 7.35, pO2 of 60, and pCO2 60. The patient
has a cardiac output of 5, and a Hgb of 8. Oxygen delivery will
increase the most by:
 Increasing cardiac output by 1
 Increasing hemoglobin by 2
 Increasing FiO2 by 10%
 Decreasing CO2 by 10%
 Oxygen delivery = CO x[(Hgb x1.34x O2 sat) + (0.003x
PaO2)]