1. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Chapter 46 Monitoring the Patient in the Intensive Care Unit

2. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 2 Learning Objectives  Discuss the principles of monitoring the respiratory system, cardiovascular system, neurological status, renal function, liver function, and nutritional status of patients in intensive care.  Discuss the risks and benefits of intensive care unit (ICU) monitoring techniques.  Discuss why the caregiver is the most important monitor in the ICU.  Describe how to evaluate measures of patient oxygenation in the ICU.

3. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 3 Learning Objectives (cont.)  Define why Paco 2 is the single best index of ventilation for critically ill patients.  Describe the approach used to evaluate changes in respiratory rate, tidal volume, minute ventilation, Paco 2, and end-tidal Pco 2 values for monitoring purposes.  Discuss monitoring techniques used in the ICU to evaluate lung and chest wall mechanics and work of breathing.  Discuss the importance of monitoring peak and plateau pressures in patients receiving mechanical ventilatory support.

4. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 4 Learning Objectives (cont.)  Introduce monitoring techniques that have become available recently such as stress, strain, FRC, stress index, Electrical Impedance Tomography and Acoustic Respiratory Monitoring.  Describe the approach used to interpret the results of ventilator graphics monitoring.  Describe the cardiovascular monitoring techniques used in the care of critically ill patients and how to interpret the results of hemodynamic monitoring.

5. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Learning Objectives (cont.)  Discuss the importance of neurological status monitoring in the ICU and the variables that should be monitored.  Discuss evaluation of renal function, liver function, and nutritional status in intensive care.  Describe and discuss the use of composite and global scores to measure patient status in the ICU, such as the Murray lung injury score and the APACHE severity of illness scoring system.  Discuss monitoring and troubleshooting of the patient  ventilator system in the ICU. 5

6. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 6 Introduction to Monitoring  Continuous monitoring or periodic checks  Gray area between diagnostic and monitoring procedures Risk/benefit ratio

7. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 7 Monitored Values  All data must be evaluated in context of overall clinical presentation  Instrument inaccuracy  recalibrate  Artifacts  Factitious events: true but temporary (cough)  Treat pathology, not errant number  All values monitored must be considered in relation to what pathology has altered them and how best to treat the pathology

8. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 8 Respiratory Monitoring  Gas Exchange  Arterial Blood Gas pH PaCO 2 PaO 2 Calculated HCO 2 Estimated base excess or deficit SaO 2  Oxygenation  Ventilation

9. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Monitoring 9

10. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 10 Monitoring Oxygenation  Tissue oxygenation depends on CaO 2 (PaO 2 and SaO 2 ), cardiac output, and oxygen uptake  Pulse oximetry (“fifth vital sign”)  Provides noninvasive measurement of SaO 2, referred to as SpO 2  Monitors only oxygen, not ventilation  Significant limitations

11. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 11 All of the following are true about pulse oximetry monitoring, except: A.Provides an SpO 2 reading B.Provides invasive measurement of SaO 2 C.Monitors only oxygen, not ventilation D.Significant limitations

12. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 12 Monitoring Oxygenation (cont.)

13. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 13 All of the following values affect pulse oximetry, except: A.Nail polish B.Deeply pigmented skin C.Anemia D.CO 2 buildup

14. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 14 Other Oxygen Indices  Oxygen consumption  Difficult to measure, so seldom used  Normal 250 ml/min, 25% of oxygen delivery  P(A  a)O 2  Healthy patient 21% O 2, gradient is 5 to 15 mm Hg 100% O 2, gradient is 100 to 150 mm Hg  Abnormal increase associated with gas exchange problems

15. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 15 Other Oxygen Indices (cont.)  PaO 2 /FIO 2 ratio (P/F ratio)  Normal P/F ratio is 400 to 500.  In Acute Lung Injury - ALI, this falls below 300.  In Acute Respiratory Distress Syndrome - ARDS, will be < 200.  Most reliable index of gas exchange if FIO 2 > 0.50 and PaO 2 < 100 mm Hg  Q S /Q T (physiologic shunt)  Increased if pulmonary venous admixture occurs (mixed venous blood exits A/C membrane unchanged)

16. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 16 Which of the following PaO 2 /FIO 2 ratio identifies a patient with ARDS? A.500-600 B.300-500 C.>200 D.<200

17. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 17 Monitoring Ventilation  Routine monitoring includes  PaCO 2, which defines adequacy of ventilation  V T, f, and V E Low V T and high f often indicate distress  V D /V T Normal 0.20 to 0.40 Higher ratio indicates more wasted ventilation ICU common to be > 0.60 >0.60, patient is unlikely to sustain spontaneous ventilation VV..

18. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 18 Monitoring Ventilation (cont.)  Inspired vs. Expired Tidal Volume  Normal Inspired – (VTI) and expired tidal volume (VTE) should be nearly equal. Air leak will result in higher VTI than VTE.  Capnography  Capnometry

19. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Monitoring Ventilation (cont.) 19

20. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 20 All of the following are true regarding VD/VT ratio, except: A.Normal 0.40 to 0.60 B.Higher ratio indicates more wasted ventilation C.ICU common to be >0.60 D.If >0.60, patient is unlikely to sustain spontaneous ventilation

21. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 21 Compliance  Compliance is ΔV/ΔP or effective V T /(P plat  PEEP).  Normally, is 60 to 100 ml/cm H 2 O  In severe ARDS, may be <25-30 ml/cm H 2 O  Many pulmonary diseases alter compliance See Box 46-7.

22. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 22 Resistance  Resistance (Raw) = (PIP  P plat )/flow  Normally 1 to 2 cm H 2 O/L/sec  Intubated, typically 5 to 10 cm H 2 O/L/sec or more  See Box 46-7 for diseases that alter Raw

23. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 23 Auto-PEEP  If exhalation is incomplete, intrinsic or auto- PEEP occurs  Causes ⇑ FRC and mean alveolar pressure  Often causes patient  ventilator asynchrony  Ways to decrease auto-PEEP  Decrease V E  Increase E T  Decrease I T

24. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 24 Auto-PEEP (cont.)  Adding extrinsic PEEP may overcome the trigger sensitivity issue and facilitate lung emptying  Slowly increase in 1-2 cm H 2 O increments until either: Patient can trigger the ventilator Auto-PEEP increases

25. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 25 Measuring Auto-PEEP  Presence noted by expiratory flow at end of expiration  Measured by  End-expiratory hold: most common method Allows alveolar pressure to equalize with ventilator pressure.  Esophageal balloon  Increase PEEP until end-expiratory flow is zero PEEP applied estimates auto-PEEP

26. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 26 Auto-PEEP can be measured by all of the following, except: A.Esophageal balloon B.Inspiratory pause C.Increase PEEP until end-expiratory flow is zero D.End expiratory hold

27. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 27 Monitoring Breathing Effort & Pattern  P 0.1 assesses ventilator drive  Occlusion pressure 100 ms after initiation of inspiration  <6 cm H 2 O is indicative of patient’s ability to wean from MV  RSBI (f/VT)  Respiratory muscle fatigue tends toward rapid shallow breathing  RSBI < 105 indicates patient likely to wean from MV The lower the RSBI the better

28. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 28 Monitoring Breathing Effort & Pattern (cont.)  Vital capacity (VC)  Effort dependent  VC less than 10 to 15 ml/kg, need for MV  Maximal inspiratory pressure (MIP)  Not effort dependent, as prolonged occlusion of airway stimulates maximal effort  More negative is better  20 to  30 cm H 2 O acceptable

29. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. MIP 29

30. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Work of Breathing 30

31. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 31 Monitoring During Lung Protective Ventilation  Commonly used for ALI/ARDS patients to avoid ventilator-induced lung injury (VILI)  Three principles confirmed  Limit P plat to < 28 cm H 2 O  Reduce V T to 4–8 ml/kg  Use adequate PEEP to avoid opening/closing injury  Permissive hypercapnia is often used as a lung protective strategy avoid VILI

32. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 32 Cardiac & Cardiovascular Monitoring  Arterial blood pressure  Invasive or noninvasive  Central venous pressure (CVP)  Pulmonary arterial catheter: high risk-to-return ratio, so only used on most complicated patients  Allows monitoring of Cardiac output/cardiac index Pulmonary arterial pressure Pulmonary capillary wedge pressure Pulmonary vascular resistance Systemic vascular resistance

33. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Cardiac & Cardiovascular Monitoring 33

34. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Cardiac & Cardiovascular Monitoring 34

35. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 35 Pulmonary arterial catheter allows monitoring of all of the following, except: A.Cardiac output/cardiac index B.Pulmonary and Systemic vascular resistance C.Peripheral vascular wedge pressure D.Pulmonary arterial pressure

36. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 36 Hemodynamic Monitoring  Complete hemodynamic profile from PA catheter eases determination of cause for altered hemodynamic status  Table 46-4 shows expected changes in hemodynamic values associated with clinical presentation of cardiac or cardiovascular dysfunction

37. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 37 Neurologic Monitoring  Neurologic dysfunction is difficult to recognize in sedated patient  Obtain history, from family if not from patient  Neurologic examination  Mental status  Pupillary response and eye movement  Corneal and gag reflex  Respiratory rate and pattern  ICP monitoring (10 to 15 mm Hg normal)  Glasgow Coma Scale (see Table 46-6)

38. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 38 Monitoring Renal Function  Kidney functions  Filtering and excretion of wastes  Regulates fluid and electrolyte composition  Renal failure is noted by  BUN increases of 10 to 15 mg/dl/day  Creatinine increases of 1 to 2.5 mg/dl/day  Urine volume reflects renal perfusion Oliguria <400 ml/day in average-sized adult Anuria occurs with <50 ml/day

39. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 39 Monitoring Nutritional Status  Adequate nutrition key for healing  Assessment for malnutrition important  Including organ function and muscle wasting  Serum albumin concentration most common <2.2 g/dl reflects severe malnutrition; shows chronic, not acute, change Also altered by sepsis, dehydration, trauma

40. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 40 Estimating Nutritional Needs  First step is estimating caloric need  Estimate the basal energy expenditure, or BEE  Harris-Bennedict equation estimates BEE  Men = 66 + (13.7) (wt) + 5 (ht) – 6.8 (age)  Women = 65 + (9.6) (wt) + 1.8 (ht) – 4.7 (age)  For ill patients, often multiply the result by a stress factor of 0.5 to 2.5.