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Physiologic Monitoring of the Surgical Patient

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Physiologic Monitoring of the Surgical Patient Powered By Docstoc
					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
       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
   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
   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
       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)]

				
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