Hemodynamic monitoring- Dr Sandeep Gampa


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Hemodynamic monitoring- Dr Sandeep Gampa

  1. 1.  Hemodynamic monitoring -cornerstone in the management of the critically ill patient  Identify impending cardiovascular insufficiency, its probable cause, and response to therapy.  Despite the many options available, utility of most hemodynamic monitoring is unproven
  2. 2. Physicians have developed a psychological dependence on feedback from continuous hemodynamic monitoring tools, independent of their utility  Effectiveness of hemodynamic monitoring to improve outcome limited to specific patient groups and disease processes for which proven effective treatments exist 
  3. 3. “To help direct management in medical patients in whom hemodynamics will alter treatment and clinical estimates are unreliable”  “To assist management of surgical patients”  “To establish or assist in establishing specific diagnoses” – Cardiac vs. non-cardiac pulmonary edema – VSD vs. MR in acute MI – Pericardial tamponade – RV MI 
  4. 4. Monitoring device will improve patientcentered outcomes when coupled to a treatment which, itself, improves outcome  Time -crucial for early diagnosis of hemodynamic catastrophe -earlier therapy improves outcome in this situation  N Engl J Med 2001; 345:1368–1377
  5. 5. Non Invasive Clinical variables  BP  ECG  Echocardiography   O2 saturation
  6. 6. Invasive  CVP  SvO2, Mixed venous oxygen saturation (from the central venous line  Arterial  Cardiac catheter output  PA Catheter
  7. 7. Blood pressure  Heart rate and rhythm  Rate of capillary refill of skin after blanching  Urine output  Mental status 
  8. 8.  Proper  Width  Lower Fit of a Blood Pressure Cuff of bladder = 2/3 of upper arm edge of cuff approximately 2.5 cm above the antecubital space
  9. 9.  Too small  Too LARGE causes false-low reading causes false-high reading
  10. 10.  Normal blood pressure ≠hemodynamic stability  Hypotension (MAP < 65 mmHg) is always pathological.
  11. 11.  Errors in measurement : › Long stethoscope tubing › Poor hearing in observer › Calibration errors of sphygmomanometer › Decreased blood flow in the extremity › Severe atherosclerosis (unable to occlude) › Inappropriate cuff size › Too rapid deflation
  12. 12. Intra-arterial catheters ("art lines") are a reliable method to continuously monitor systemic blood pressure.  A NORMAL WAVE form will be: - Within the normal parameter of blood pressure - Present a characteristic shape - Synchronous with the EKG waveform 
  13. 13. The normal peripheral arterial waveform will display the peak systolic pressure after the QRS.  This phenomenon reflects the time it takes the cardiac systolic pressure wave to reach the peripheral catheter and sensor.  The dicrotic notch reflects the closure of the aortic valve. 
  14. 14. Overdamping: seen as a smooth waveform that loses the dicrotic notch.  It can be caused by air bubbles in the system, too many stopcocks, kink in the catheter or tubing, blood on the transducer, a clot in the catheter, an empty flush bag, aortic stenosis, vasodilation or a low cardiac output
  15. 15. Underdamping: seen as a sharp exaggerated waveform with overshoot of the systolic pressure and undershoot of the diastolic.  It can be caused by excessive tubing, excessive catheter movement, atherosclerosis, vasoconstrict ion, aortic regurgitation, hyperdynamic states and hypertension.
  16. 16.  Arterial Catheter  Pressure Tubing  Pressure Cable  Flush – 500cc NS 19
  17. 17.  Hemorrhage  Air Emboli  Infection  Altered Skin Integrity  Impaired Circulation
  18. 18.   Improper set-up and equipment malfunction are the primary causes for hemodynamic monitoring problems Retracing the set-up process or tubing (patient to monitor) may identify the problem and solution quickly 21
  19. 19. Damped Waveforms  Pressure bag inflated to 300 mmHg  Reposition extremity or patient  Verify appropriate scale  Flush or aspirate line  Check or replace module or cable 22
  20. 20. Inability to obtain/zero waveform  Connections between cable & monitor  Position of stopcocks  Retry zeroing after above adjustments 23
  21. 21.  What is the target BP ? No threshold BP that defines adequate organ perfusion among organs, between patients, or in same patient over time  Based mainly on anecdotal experience, a systolic pressure of 100mmHg usual target, with HR < 120 /min-Controversial  Curr Opin Crit Care.2001; 7:422–430  MAP ≥ 65 mmHg -Initial target in septic shock,>40 mmHg in hemorrhagic shock and > 90 mmHg in Traumatic brain injury –Level 1 B Intensive Care Med. 2007; 33:575–590 International Consensus Conference Surviving sepsis Campaign 2008
  22. 22. Arrhythmia Monitoring –Up to 95% of AMI have arrhythmia within 1st48 hrs  Up to 1/3 have VT. Early diagnosis and prompt treatment may improve survival  Heart rate variability may reflect prognosis   Ischemia Monitoring –Significant uncertainty to reliably detect myocardial ischemia and diagnose MI in critically ill patients
  23. 23. Evidence  Ischemia in ICU related to pain, fluid balance, fever, catecholamine levels, or other physical stresses  Hurford et al -worsening of ischemia (cont ECG ) in patients rapidly weaned from positive pressure to spontaneous ventilation  Continuous ECG monitoring in ICU detected a 6.4% incidence of ischemia during weaning  Patients with ischemia fail to wean more commonly
  24. 24.  Sole imaging modality that provides realtime information on cardiac anatomy and function at bedside  Ideally suited to early hemodynamic evaluation of patients with persistent shock despite aggressive goal-directed therapy
  25. 25. Hemodynamic instability –Ventricular failure –Hypovolemia –Pulmonary embolism –Acute valvular dysfunction –Cardiac tamponade       -Complications after cardiothoracic surgery -Infective endocarditis -Aortic dissection and rupture -Unexplained hypoxemia -Source of embolus
  26. 26.  High image quality vital–Aortic dissection -Intracardiac thrombus –Assessment of endocarditis  Inadequately seen by TTE –Thoracic aorta -Left atrial appendage –Prosthetic valves
  27. 27.  Inadequate image clarity with TTE –Severe obesity –Emphysema Mechanical ventilation with high-level PEEP  Presence of surgical drains, surgical incisions, dressings  Acute perioperative hemodynamic derangements 
  28. 28. Myocardial or coronary perforation secondary to catheter-based interventions (pacemaker lead insertion, central catheter placement, or percutaneous coronary interventions)  Uremic or infectious pericarditis  Compressive hematoma after cardiac surgery  Proximal ascending aortic dissection 
  29. 29. Blunt or penetrating chest trauma  Complication of myocardial infarction (e.g., ventricular rupture)  Pericardial involvement by metastatic disease or other systemic processes 
  30. 30.  Changes in management after TEE in 30– 60% of patients leading to surgical interventions in 7–30% Crit Care Med 2007; 35[Suppl.]:S235-4  Critically ill patients with unexplained hypotension, new diagnoses were made in 28% -leading to surgical intervention in 20% J Am Coll Cardiol 1995; 26:152–2
  31. 31.  ECHO for diagnosis in patients with clinical evidence of ventricular failure and persistent shock despite adequate fluid resuscitation -Level 2 B Intensive Care Med. 2007; 33:575–590 International Consensus Conference
  32. 32. All physicians in charge of critically ill patients should be trained in goal directed echocardiography  Far from being competitive or conflicting, use of echocardiography by intensivists and cardiologists is complementary  German Society of Anesthesiology and Intensive Care Medicine-already developed their own certification  Brief (10 hrs) formal training in using a handheld ECHO system, intensivists able to successfully perform limited TTE in 94% of patients and interpreted correctly in 84% changed management in 37% of patients.  Intensive Care Med .2008.34:243–249
  33. 33. Describes the pressure of blood in the thoracic vena cava, near the right atrium of the heart.  Normal Value: 2-6 mmHg (7-12 cm H2O)  Reflects blood volume, RV performance, and venous tone.  May reflect LV filling pressures in patients with normal LV function (EF > 40%), valves, and pulmonary status.
  34. 34. Leveling  Standard reference level for assessment sternal angle, 5 cm vertically above the mid-point of the right atrium -even when the person sits up at a 60ºangle  In supine patient, reference level intersection of the fourth intercostal space with midaxillary line (3 mm Hg / 4.2 cm > sternal angle measurement )
  35. 35. CVP, should be made at end expiration pleural pressure is closest to atmospheric pressure  intrinsic or extrinsic PEEP, pericardial fluid, or increased abdominal pressure can increase CVP  PEEP of 10 cmH2O, increases the measured CVP by less than 3 mmHg in normal lung and even less in deceased lung 
  36. 36.  4th intercostal space, mid-axillary line  Level of the atria (Edwards Lifesciences, n.d.) 40
  37. 37.  CVP only elevated( > 10 mm Hg ) in disease, but clinical utility of CVP as a guide to diagnosis or therapy has not been demonstrated  If CVP is ≤ 10 mmHg then CO decrease when 10 cm H2O PEEP applied whereas a CVP above 10 mmHg -no predictive value
  38. 38.  Fluid resuscitation initially target a CVP of at least 8 mm Hg (12 mm Hg in mechanically ventilated patients)-Level 1C
  39. 39.  However no threshold value of CVP that identifies patients whose CO will increase in response to fluid resuscitation.
  40. 40.  Provides global estimation of adequacy of oxygen delivery (DO2 ) relative to tissue needs.  SvO2 = SaO2 - (VO2/(CO x 1.34 x Hb))  If O2 sat, VO2 & Hb remain constant, SvO2 is indirect indicator of CO  Can be measured using from blood gas from distal lumen of PA catheter  Normal SvO2 ~ 65% [60-75]
  41. 41. ↑ SvO2 [> 75%] › Wedged PAC: reflects LAP saturation › Low VO2: hypothermia, general anesthesia, NMB › Unable to extract O2: CO poisoning › High Cardiac output: sepsis, burns, L→ R shunt, AV fistulas
  42. 42. ↓ SvO2 [< 60%] › Low CO: MI, CHF, hypovolemia › Low Hb : bleeding, shock › ↓ SaO2 : hypoxia, resp distress › ↑ VO2: fever, agitation, thyrotoxic, shivering
  43. 43.  SvO2 is a balance between oxygen consumption and oxygen delivery › Normal: 60-80%  ScvO2 (Pre-Sep) catheter is placed in superior vena cava or right atrium › ScvO2 is always 5-18% >SvO2 in septic shock › Goal: ScvO2>70% › Use just like any other central line
  44. 44. The Nobel Prize in Physiology or Medicine 1956 “…develop a technique for the catheterization of the heart. This he did by inserting a canula into his own antecubital vein, through which he passed a catheter for 65 cm and then walked to the X-ray department, where a photograph was taken of the catheter lying in his right auricle.” -The Nobel Foundation 1956
  45. 45. The purpose of this catheter is to :       Evaluate the hemodynamic treatments and measure the patient’s hemodynamic status Indirectly measures the LAP by wedging a catheter into a small pulmonary artery tightly enough to block flow from behind and thus to sample the pressure beyond. (PCWP : 5-12mm Hg) Draw mixed venous blood samples Obtain central vascular pressures measurements Evaluation of cardiac output in complex medical situations Prophylactic insertion for high-risk surgeries
  46. 46.  Fick Method (ADOLF FICK in 1870) › Amount of oxygen picked up by the blood as it passes through the lungs must be equal to the amount of oxygen taken up by the patients lungs during respiration › Concept that oxygen consumption = oxygen extraction by the tissues per unit time from the circulation › O2 Extracted (VO2) = (CaO2 CvO2) x CO › CO = VO2/(CaO2-CvO2)
  47. 47.  Indicator Dilution › Dye Dilution › Thermodilution  Current Method Of Choice  inert indicator without drawing of blood  cold injectate into RA with resulting temp change detected at PA thermistor  modified Stewart-Hamilton equation solved by computer (area under temp versus time curve)  CO is inversely proportional to area
  48. 48. Absolute  Tricuspid or Pulmonary valve stenosis  RA or RV masses  Tetralogy of Fallot Relative  Severe arrhythmias  Coagulopathy  Newly inserted pacemaker wires
  49. 49. Arrhythmias, complete heart block  Valvular damage  Catheter knotting and entrapment  Endobronchial hemorrhage  Pulmonary infarction  Thrombocytopenia, thrombus formation  Incorrect placement, balloon rupture 
  50. 50. Clinical management involving the early use of PAC in patients with shock, ARDS or both did not significantly affect morbidity and mortality. JAMA 2003; 290:2717-2720
  51. 51.  PAC is a classical tool for hemodynamic assessment since it enables continuous monitoring of numerous hemodynamic parameters such as tissue oxygenation variables and estimates of cardiac filling pressures that are not provided by other monitoring devices.
  52. 52.  A large recently published metaanalysis of RCT demonstrated that its use does not cause harm to critically ill patients. (Shah et al JAMA. 2005;294: 1664-1670)  The heterogeneous results should be interpreted in light of the specific interventions tested, the delay for inclusion and the case mixed of the patients, and not of the choice of PAC per se as a monitoring tool
  53. 53. TEE produced a change in therapy in at least one third of ICU patients, independent of the presence of a PAC  Study by Benjamin et al. TEE was performed in 12 ±7 mins vs. ≥ 30 mins for PAC insertion  Bedside echocardiography has a better safety profile  PAC continuous monitoring technique to assess the response to a therapeutic intervention 
  54. 54. Advantages Less-Invasive Than Thermodilution  Real Time/ Repetitive Monitoring  Disadvantages Needs Recalibration  Dependent on Compliance of Arterial Tree  Little Validation in Patients with Shock 
  55. 55. The PiCCO Technology is a combination of 2 techniques for advanced hemodynamic and volumetric management without the necessity of a pulmonary artery -∆T -∆T catheter in most patients:  t a. Transpulmonary thermodilution t b. Arterial pulse contour analysis
  56. 56. Transpulmonary thermodilution measurement simply requires the central venous injection of a cold (<8°C) or room-tempered (<24°C) saline bolus…  After which, the thermistor in the tip of the arterial catheter measures the temperature changes  The cardiac output is calculated by analysis of the thermodilution curve using a modified Stewart-Hamilton algorithm 
  57. 57. -Tb Injection CV Bolus Injection t PiCCO Catheter e.g. in femoral artery
  58. 58. via intermittent transpulmonary thermodilution  Transpulmonary cardiac output (C.O.)  Intrathoracic blood volume (ITBV)  Global end diastolic volume (GEDV)  Extravascular lung water (EVLW)  Cardiac function index (CFI)
  59. 59. Global Enddiastolic Volume (GEDV) is the volume of blood contained in the 4 chambers of the heart.  Global End diastolic Blood Volume GEDV: 680 – 800 ml/m2 
  60. 60. Intrathoracic Blood Volume (ITBV) is the volume of the 4 chambers of the heart + the blood volume in the pulmonary vessels.  Intrathoracic Blood Volume Index ITBI: 850 – 1000 ml/m2 
  61. 61. Extravascular Lung Water (EVLW) is the amount of water content in the lungs. ( Normal : 3 – 7 ml/kg)  It allows bedside quantification of the degree of pulmonary edema. EVLW has shown to have a clear correlation to severity of ARDS, length of ventilation days, ICU-stay and mortality and shown to be superior to assessment of lung edema by CXR. 
  62. 62. Intrathoracic Blood Volume (ITBV) and Global End diastolic Volume (GEDV) have shown to be far more sensitive and specific to cardiac preload than the standard cardiac filling pressures CVP + PCWP but also than right ventricular end diastolic volume.  The striking advantage of ITBV and GEDV is that they are not wrongly influenced by mechanical ventilation and give correct information on the preload status under any condition. 
  63. 63. via continuous pulse contour analysis  Continuous pulse contour cardiac analysis (PCCO)  Arterial blood pressure (AP)  Heart rate (HR)  Stroke volume (SV)  Stroke volume variation (SVV)  Systemic vascular resistance (SVR) calculated as (MAP- CVP) / CO
  64. 64.         Principle - Lithium hemodilution cardiac output Lithium dilution curve with arterial wave form analysis calibrated with lithium dilution Injectate is an isotonic solution of lithium chloride 0.15 -0.30 mmol for an average adult Arterial pulse power analysis which estimates stroke volume & flow Invasive Continuous CO data Peripheral or Central venous line for injectate (No PA catheter needed) Peripheral arterial line needed to attach sampling probe
  65. 65. Cardiac Output = (Lithium Dose x 60)/(Area x (1-PCV))
  66. 66. Patients on lithium therapy  Patients on muscle relaxants (atracurium)  Weight < 40 kgs  First trimester of pregnancy period  Renal dysfunction or dialysis 
  67. 67. Principle : Indirect FICK calculation with partial CO2 rebreathing technique  Uses CO2 production and difference in CO2 tension from normal respiration and re-breathing to calculate CO  No intravascular access needed 
  68. 68. Requires endotracheal intubation  Most accurate with stable respiratory and metabolic rate  Completely non invasive  Placement of NICO sensor between endotracheal tube & breathing circuit Y piece 
  69. 69.         CO/CI SV Pulm capill blood flow ETCO2 Inspired CO2 RR SpO2 HR       PEEP Mean airway pressure PIP Minute volume Dynamic compliance Airway resistance
  70. 70. Non invasive  No risks of infection  Automated & continuous  Not technique dependent  Proven accuracy  Extremely simple to set up & use  Cost effective 
  71. 71. Sepsis is accompanied by hypermetabolic state, with enhanced glycolysis and hyperlactataemia -not due to hypoxia  Marker of tissue perfusion and adequacy of resuscitation  Blood lactate concentration in excess of 4 mmol /L: is associated with a high risk of mortality 
  72. 72.  Appropriate to use elevated lactate trigger to initiate aggressive care-Level 1C › In the event of hypotension and/or lactate > 4 mmol/l (36 mg/dl):–initial minimum of 20 ml/kg of crystalloid (or colloid equivalent) › Apply vasopressors for hypotension not responding to initial fluid resuscitation to maintain MAP >65 mmHg
  73. 73. A knowledge deficit disorder continues to exist in ICU regarding ideal hemodynamic monitoring  Major problem is the user not the device of monitoring  Not everything that counts can be counted; And not everything that can be counted
  74. 74. Thank You