All This Monitoring What's Necessary, What's Not

Transcription

1 All This Monitoring What's Necessary, What's Not James S. Tweddell, MD The S. Bert Litwin Chair, Cardiothoracic Surgery, Children s Hospital of Wisconsin. Professor of Surgery and Pediatrics, Chair, Division Cardiothoracic Surgery, Medical College of Wisconsin. Herma Heart Center May 5, 2013

2 Disclosures I have nothing to disclose

3 All This Monitoring What's Necessary, What's Not

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5 Pediatric ICU Challenges of Monitoring 298 monitored hours evaluated 86% of a total 2,942 alarms were found to be falsepositive alarms 6% clinically irrelevant true alarms. 8% of all alarms tracked during the study period were determined to be true alarms with clinical significance. 18% associated with patient intervention Tsien CL, Fackler JC. Crit Care Med 1997

6 Challenges of Perioperative Care 112 estimates of cardiac output by 27 clinicians on 36 intubated pediatric 2V patients Physical exam and laboratory data available Compared with thermodilution C.O. Clinicians cannot accurately determine CO of intubated pediatric patients with in-series circulation Are we any better with single ventricle patients with parallel circulation? Tibby, S. M et al. Arch Dis Child 1997;77:

7 Perioperative Management Remains Center Specific With a High Degree of Variability 1 Evidence = Divergence of Opinion

8 Demonstrating Effectiveness of Monitoring Monitoring should identify circulatory perturbation in a timely manner to permit effective therapy. Real time and easy to interpret Demonstrating effectiveness is difficult There has to be an accepted treatment strategy The treatment must be promptly applied

9 Things we routinely monitor: ECG, invasive blood pressure, central venous pressure, pulse oximetry and capnography

10 Electrocardiography Initially recorded with a string galvanometer 1895 Einthoven (Nobel Prize 1924) 1930s cathode ray oscilloscope Heart Rate, rhythm and Ischemia ECG monitoring is standard of care for all anesthetics and basic ICU monitoring* Randomized trials are not feasible Evidence of utility case series and observational studies *Drew BJ et al Circ 2004

11 Invasive Arterial Pressure Monitoring Guidelines mandate that arterial blood pressure be monitored during all anesthetic procedures and in the ICU 1 Invasive monitoring is necessary for cardiac surgery Randomized trials are not feasible Observational studies have established a correlation between BP and cardiovascular events 2,3 Blood pressure cardiac output 1. ASA Kilgannon JH et al Resuscitation Trzeciak S et al Crit Care Med 2009

12 ΔavO2, vol % Blood Pressure Cardiac Output No relationship between ΔavO2 and BP Postoperative hourly data after the Norwood procedure, n=9563: r = Mean Arterial Pressure (mmhg)

13 Central Venous Pressure Monitoring Intravascular volume assessment Central venous lines also useful for Inadequate peripheral iv access Frequent blood sampling Vasoactive or irritating drug administration TPN Randomized trials are not feasible

14 ΔavO 2 (vol %) Central Venous Pressure Not Much Help Hourly data, n=9697: r 2 = Central Venous Pressure (mmhg)

15 Left Atrial Line Provides information on left ventricular pre-load Routine use is much less common Is there additional benefit after a satisfactory TEE? Indications After biventricular repair with concern for LV function, size and/or compliance Fontan Ebstein s anomaly

16 Pulse Oximetry Pulse oximetry uses a combination of two technologies: spectrophotometry, whereby saturation of hemoglobin with oxygen is estimated; and optical plethysmography, which focuses the measurement on pulsatile blood arterial flow. Sources of error; movement, C.O., dyshemoglobinemia, tissue pigment, temperature, probe site and artificial light

17 152 children (non-cardiac) undergoing surgery were divided into two groups; 76 each One with pulse oximetry data immediately available to care providers and the other blinded to pulse oximetry data except when SpO 2 < 85% Pulse oximetry more likely to identify hypoxic events Pulse oximetry identified hypoxia before clinical signs (bradycardia, cyanosis) Risk factors for hypoxia: age < 2, ASA 3 or 4 patients

18 Pulse Oximetry Standard of care since 1990 Reduces number of arterial blood gas samples taken Shorter duration of oxygen weaning Increased detection of hypoxic events c/w clinical assessment Clinical assessment alone identified only half of the hypoxic events but no data showing improvement in outcome Duration of mechanical ventilation Mortality or morbidity

19 Pulse Oximetry Schmitt HJ et al J Cardiothorac Vasc Anesth 1993

20 Pulse Oximetry Schmitt HJ et al J Cardiothorac Vasc Anesth 1993

21 Pulse Oximetry Schmitt HJ et al J Cardiothorac Vasc Anesth 1993

22 Pulse Oximetry Schmitt HJ et al J Cardiothorac Vasc Anesth 1993

23 Capnometry and Capnography Guidelines require availability of CO 2 monitoring on ventilated patients, continuous capnography suggested 1-3 Integrity of ventilation occlusion/displacement of ET tube, airway obstruction, apnea Predictor of PaCO 2 Weaning of mechanical ventilation Noninvasive predictor of pulmonary blood flow Shunt patency, degree of right to left shunting Measure of CO 2 production 1. Rosenberg DI, Moss MM Pediatrics Kleinman ME et al Circ Walsh BK et al Respiratory Care 2011

24 Monitoring Cardiac Output

25 Measures of cardiac output Fick method Differential carbon dioxide Fick partial rebreathing technique Dye dilution Lithium indicator dilution Thermodilution Continuous waveform analysis Electrical impedance cardiography Doppler ultrasound

26 Measures of cardiac output Fick method Differential carbon dioxide Fick partial rebreathing technique Dye dilution Lithium indicator dilution Thermodilution Continuous waveform analysis Electrical impedance cardiography Doppler ultrasound

27 Continuous waveform analysis 31 patients; heart failure, pulmonary hypertension or following heart transplantation Thermodilution v FloTrac Patients with BSA 1 m 2

28 Continuous waveform analysis 31 patients; heart failure, pulmonary hypertension or following heart transplantation Thermodilution v FloTrac Patients with BSA > 1 m 2

29 Other Measures of Circulatory Well-Being

30 Gastric Tonometry During shock the gut vasoconstricts in order to redirect the limited cardiac output to the more vital organs Hypoperfusion results in regional hypercapnea Hypoperfusion occurs when gastric mucosal PCO 2 is 8 mmhg higher than arterial PCO 2 H 2 O

31 Evidence of utility Gastric Tonometry 2 RCTs in adult patients inconclusive No RCTs in pediatric cardiac surgical patients 5 prospective observational studies in pediatric cardiac surgical patients - inconclusive 1. Wippermann CF et al Eur J Cardiothorac Surg Perez A et al Crit Care Med de Souza RL et al Arg Bras Cardiol Pigula FA et al Ann Thorac Surg Kaufman J et al Pediatr Crit Card Med 2008

32 Venous Saturation Monitoring SvO 2 is the summed average of the last blood in contact with cells in the capillary bed a reflection of the balance between oxygen delivery DO 2 and oxygen consumption VO 2 SVC (SsvcO 2 ) saturation used as an approximation Has been demonstrated to be of benefit in RCT in pediatric patients with sepsis

33 Anaerobic Risk SVC Saturation and the Anaerobic Threshold patient hours * Anaerobic threshold ~ 30% * p<0.001 by L-R test <30% 31-40% 41-50% 51-60% >60% SsvcO 2 (%) Hoffman GM et al Ann Thorac Surg 2000

34 SVC Saturation is Related to Outcome Norwood procedure with BT shunt n = 116 SsvcO2 predicts CPR, ECMO, and death Any complication SsvcO 2 for 48 hours Any mortality CPR Any ECMO S1P mortality 1st 48 hour ECMO Tweddell JS et al Ann Thorac Surg 2007

35 Monitoring SsvcO 2 Permits Intervention that Improves Outcome 50:50 randomization of 102 children with sepsis 51 continuous SsvcO 2 monitoring 51 intermittent SVC measured saturations not available to investigators Control v Intervention Group Patients with SsvcO 2 < 70% Control v Intervent. Group 1. de Oliveira CF, et al Intensive Care Med Rivers E, et al NEJM 2001

36 Near Infrared Spectroscopy (NIRS) optical window of nm The ratio of HbO 2 /Hb can be determined

37 Two site NIRS Monitoring regional blood flow monitoring lower S/C ratio in NEC best cut point ~ 0.75 odds ratio ~ 8x, p< ROC: CSOR = 0.91 ( ) TOI abdo = 0.83 ( ) NEC No NEC Total S/C < S/C > Total Somatic to Cerebral ratio more predictive than abdominal signal alone Fortune PM et al, Int Care Med 2001

38 Predicted Probabilities and 95% CI for Outcomes NIRS: Predicts Shock, Complications and Mortality 79 neonates S/P S1P, 3792 hours of postop rso 2 data Any Complications Biochemical Shock.7 Mortality Somatic-Cerebral Saturation Difference Hoffman et al Anesthesiology 2007; 107: A234

39 Two Site NIRS Monitoring Correlates With SVC Saturation Measured SsvcO 2 Two Site NIRS Model SVC Saturation 1. Hoffman GM et al Semin Thorac Cardiovasc Surg Pediatr Card Surg Kaufman et al Pediatr Crit Care Med Ranucci M et al Pediatr Anesth 2008

40 Neuromonitoring Transcranial Doppler EEG NIRS

41 Transcranial Doppler Most commonly MCA through the temporal window Measures cerebral blood flow velocity not blood flow Trend information Δ cerebral vascular resistance Cannula malposition Cerebral emboli - HITS Research tool Cerebral vascular autoregulation Cerebral blood flow during hypothermic CPB and antegrade cerebral perfusion Andropolous DB. In Monitoring in Anesthesia and Perioperative Care 2011

42 Transcranial Doppler Evidence of utility No clear association between number of HITS and neurodevelopmental outcomes 1,2 Difficult to perform for long periods of time 3 Significant learning curve 3 1. Dittrich R, Ringelstein B. Stroke Martin KK, et al Am J Surg Andropolous DB. In Monitoring in Anesthesia and Perioperative Care 2011

43 EEG EEG detected seizures are 3 times as common as clinically detected seizures Perioperative seizures are a marker of neurologic injury and have been associated with neurodevelopmental delay Does early identification and treatment change outcome? Intraop and immediate postop EEG is cumbersome and requires expert interpretation (expensive) 1. Helmers SL et al Electroencephalogr Clin Neurophysiol Gaynor JW et al J Thorac Cardiovasc Surg 2006

44 NIRS for Neuromonitoring A strong correlation has been shown between jugular venous bulb saturation and NIRS. 1 Multiple prospective observational studies show a correlation between cerebral saturation and late neurodevelopmental outcome. 2-5 No randomized controlled trials and they are becoming increasingly unlikely 6 1. Abdul-Khaliq H et al. Biomed Tech (Berl) Kussman BD et al Circ Hoffman GM et al. J Thorac Cardiovasc Surg Sood ED,e al. J Thorac Cardiovasc Surg Andropoulos DB et al. Ann Thorac Surg Ghanayem NS, Wernovsky G, Hoffman GM. Pediatr Crit Care Med 2011

45 NIRs Predicts Neurodevelopmental Outcome rso 2 strongest predictor of low VMI score in preschool age children, 4-5 years (28% of variance) Hoffman GM et al J Thorac Cardiovasc Surg 2013

46 J Thorac Cardiovasc Surg 1997

47 Near Infrared Spectroscopy This black-box technology without the need for calibration or controls and using non-invasive sensors had led to many users believing that the only criterion for accuracy is the ability to display a believable number.

48 Near Infrared Spectroscopy This black-box technology without the need for calibration or controls and using non-invasive sensors had led to many users believing that the only criterion for accuracy is the ability to display a believable number. Smith J Understanding Pulse Oximetry. Anaesthesia and Intensive Care 1992

49 What s Necessary and What s Not? To be effective monitoring must detect perturbations in wellbeing fast enough and with enough fidelity to permit intervention Testing the utility of monitoring requires, in addition, 1. effective therapy 2. implemented in a timely manner All of the monitoring strategies we currently use are based on expert opinion, case series or at best observational studies The accumulated data concerning NIRS; expert opinion, case series and observational studies is similar to that supporting current monitoring strategies Only venous saturation monitoring from the SVC approaches level A data

50 References: Sivarajan VB, Bohn D. Monitoring of standard hemodynamic parameters: Heart rate,systemic blood pressure, atrial pressure, pulse oximetry, and end-tidal CO 2. Pediatric Crit Care Med 2011 Young D Griffiths Clinical trials of monitoring in anaesthesia, critical care and acute ward care: a review. Brit J Anaesth 2006 Montoring in Anesthesia and Perioperative Care. Reich DI, Kahn RA, Mittnacht AJ, Leibowitz AB, Stone ME, Eisenkraft JB. Cambridge University Press. 2011

51 Randomized controlled trials have demonstrated improved survival using which of the following monitoring strategies? A. Invasive blood pressure monitoring B. Near infrared spectroscopy C. Superior vena cava saturation monitoring D. Pulse oximetry Answer = C

52 Thank you

53 need for a fluid bolus Metabolic acidosis: ph < 7.25, lactate > 2, base excess -5 Oliguria < 1ml/kg/hour Escalation of inotropic support Ped Crit Care 2012

54 need for a fluid bolus Metabolic acidosis: ph < 7.25, lactate > 2, base excess -5 Oliguria < 1ml/kg/hour Escalation of inotropic support Of 31 episodes of LCO; 24 were physician behaviors and not objective evidence of LCO - NIRS did not predict physician behavior Ped Crit Care 2012

55 Challenges of Perioperative Care 112 estimates of cardiac output by 27 clinicians on 36 intubated pediatric 2V patients Physical exam and laboratory data available Compared with thermodilution C.O. Clinicians cannot accurately determine CO of intubated pediatric patients with in-series circulation Are we any better with single ventricle patients with parallel circulation? Tibby, S. M et al. Arch Dis Child 1997;77:

56 Physician Behaviour Equal Cardiac Output Wernovsky G et al. Circulation 1995