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  • 1. Case 1
    • 35 YO G3P2, uneventful pregnancy
    • Presented in labour @ 39 wks
    • Shoulder dystocia
    • Pulseless, apneic, and pale
    • Responded to PPV and chest compressions. AS 1, 3, 6, 7
  • 2. Case 1
    • At 20 min of life:
    • Ventilated, poor resp. effort, FiO 2 0.25
    • Temp 36ºC, HR 120 bpm, MBP 42 mmHg
    • Mottled skin, CRT 3-4 sec
  • 3. Case 1
    • What is the next action?
  • 4. Case 2
    • 25 YO, G2P1, regular ANC
    • Presented 3 days prior to delivery in threatened preterm labour @ 26 wks
    • No pPROM
    • Received Beta x 2, Amp and Erythro
    • Baby was born pink, HR>100, apneic
    • Intubated, Bless, Ventilated, UAC, UVC
  • 5. Case 2
    • At 1 hr of age:
    • AC/VG, PEEP 6, VG 4 ml/kg, FiO 2 0.23
    • HR 150 bpm, MBP 23 mmHg, CRT 2-3 sec
  • 6. Case 2
    • What is the next action?
  • 7. Case 3
    • 25 YO, G2P1, regular ANC
    • Presented 3 days prior to delivery in threatened preterm labour @ 26 wks
    • No pPROM
    • Received Beta x 2, Amp and Erythro
    • Baby was born pink, HR>100, apneic
    • Intubated, Bless, Ventilated, UAC, UVC
  • 8. Case 3
    • At 6 hrs of age:
    • HR 150 bpm, MBP 29 mmHg, CRT 2-3 Sec
    • AC/VG, PEEP 6, FiO 2 0.25, VG 4 ml/kg,
    • VR 40, RR 50’s
    • ABG: pH 7.22, PCO 2 37, PO 2 54,
    • HCO 3 15, BE -12
  • 9. Case 3
    • What is the next action?
  • 10. Monitoring of Neonatal Hemodynamics* Ayman Abou Mehrem, MD, CABP Neonatology Fellow University of Manitoba * Adapted from Early Human Development 86 (2010) 135-165
  • 11. Monitoring of Neonatal Hemodynamics
    • Introduction
    • Objective
    • Part 1: Clinical Monitoring of Systemic Hemodynamics
    • Part 2: Cardiac Output Monitoring
    • Part 3: Functional Echocardiography
    • Part 4: Peripheral Hemodynamics
  • 12. Introduction
    • Hemodynamics: from Greek
    • αίμα (haima): blood
    • Δύναμις (dynamis): power or strength
    • The study of the movements of blood and the forces concerned herein 1
    1 Dorland's illustrated medical dictionary. Philadelphia: Saunders; 2003
  • 13. Introduction
    • Circulation in neonates is unique:
      • Transition from low resistant placental circulation to high resistant systemic circulation
      • Presence of intra- and extra-cardiac shunts
      • Underdeveloped regulatory mechanism at the end organs in preterm neonates
  • 14. Picture from: Kliegman: Nelson Textbook of Pediatrics, 18th ed
  • 15. Introduction
    • Adequate blood circulation is necessary for adequate supply of O 2 and other essential nutrients, and to remove toxic metabolic products from all tissues
    • O 2 supply is dependent on:
      • Arterial O 2 content
      • Blood flow
    Picture from: www.learnhemodynamics.com/hemo/oxygen.htm
  • 16. Introduction
    • Arterial O 2 content
      • Hemoglobin concentration
      • Arterial O 2 saturation (SaO 2 )
    • The limitation of O2 supply monitoring
      • the ability to monitor blood flow to the tissues
  • 17. Objective
    • Review of available methods for monitoring of hemodynamics and end-organ perfusion in neonates.
    • Identify best evidence-based practice in directing the management of circulatory insufficiency in neonates, achieving hemodynamic stability and avoiding deleterious effect of various interventions.
  • 18. Part 1 Clinical Monitoring of Systemic Hemodynamics
  • 19. What do your criteria to diagnose “ circulatory insufficiency” in neonates?
  • 20. Clinical monitoring of systemic hemodynamics
    • In questionnaire across Canada: 2
      • 25.8% of the respondents rely on absolute BP values alone when defining hypotension
      • The remainder combine BP values and clinical signs of perfusion: color, capillary refill time and urine output
      • 87.1% defined hypotension as BP in mm Hg less than gestational age in weeks
    2 Dempsey EM, Barrington KJ. Diagnostic criteria and therapeutic interventions for the hypotensive very low birth weight infant. J Perinatol 2006;26:677–81.
  • 21. Blood Pressure
    • Hypotension:
      • BP < the tenth (or fifth) percentile of normative BP values from a reference population with regard to GA, BW, and postnatal age
      • The lower limit of normal MABP: the numeric value of GA in wks, provided no additional signs exist of hypoperfusion of endorgans
      • MABP < 30 mm Hg
  • 22. Blood Pressure
    • Osborn et al, 2004: 3
    • Poor correlation between BP and Systemic Blood Flow in preterm infants < 30 wks GA
    3 Osborn DA, Evans N, Kluckow M. Clinical detection of low upper body blood flow in very premature infants using blood pressure, capillary refill time, and central–peripheral temperature difference. Arch Dis Child Fetal Neonatal Ed 2004;89: F168–73.
  • 23. Blood Pressure
  • 24. Blood Pressure
    • Groves et al, 2008: 4
    • Low blood pressure does not correlate with poor perfusion in the first 48 h of postnatal life in sick preterm infants < 30 wks GA
    • Infant with reduced systemic perfusion (SVC flow < 41 ml/kg/min) tend to have normal or high blood pressure in the first hours of life.
    • High systemic vascular resistance may lead to reduced blood flow.
    4 Groves AM, Kuschel CA, Knight DB, Skinner JR. Relationship between blood pressure and blood flow in newborn preterm infants. Arch Dis Child Fetal Neonatal Ed. 2008 Jan;93(1):F29-32. Epub 2007 May 2.
  • 25. Heart Rate
    • In neonate,
    • It is supposed that cardiac output is almost entirely dependent on HR !!!??
  • 26. Heart Rate
    • Kluckow and Evans, 2000: 5
    • No correlation between HR and systemic blood flow (SBF)
      • The normal range of SBF: being above the lowest recorded SVC flow at each of the four scans, that is, above 30, 34, 42, and 46 ml/kg/min respectively at 5, 12, 24, and 48 hours of age
    5 Kluckow M, Evans N. Low superior vena cava flow and intraventricular haemorrhage in preterm infants. Arch Dis Child Fetal Neonatal Ed 2000;82: F188–94.
  • 27. Heart Rate
  • 28. Color
    • Skin and mucosal membranes color is influenced by:
      • Oxygenation
      • Hb concentration
      • Skin temperature
      • Skin thickness
      • Peripheral perfusion
      • Race
      • Gestational age
      • ambient temperature
      • Light
  • 29. Color
    • O'Donnell et al, 2007: 6
    • Among clinicians observing the same videos there was disagreement about whether newborn infants looked pink with wide variation in the SpO 2 when they were considered to become pink
    6 O'Donnell CP, Kamlin CO, Davis PG, Carlin JB, Morley CJ. Clinical assessment of infant colour at delivery. Arch Dis Child Fetal Neonatal Ed 2007;92:F465–7.
  • 30. Capillary refill time (CRT)
    • The time required for the return of color after the application of a blanching pressure to a distal capillary bed
    • Raichur et al, 2001: 7
    • There was good interobserver agreement when CRT was measured on the chest but not the forehead, palm or heel
    7 Raichur DV, Aralihond AP, Kasturi AV, Patil DH. Capillary refill time in term neonates: bedside assessment. Indian J Pediatr. 2001 Jul;68(7):613-5.
  • 31. Capillary refill time (CRT)
    • Osborn et al, 2004: 3
    • CRT > 3 sec had a sensitivity of 55% and a specificity of 80% for predicting low SVC flow
    3 Osborn DA, Evans N, Kluckow M. Clinical detection of low upper body blood flow in very premature infants using blood pressure, capillary refill time, and central–peripheral temperature difference. Arch Dis Child Fetal Neonatal Ed 2004;89: F168–73.
  • 32. Capillary refill time (CRT)
  • 33. Urine Output
    • Miletin et al, 2009: 8
    • There was a poor correlation between the capillary refill time, MBP, urine output and low SVC flow (< 40 ml/kg/min)
    8 Miletin J, Pichova K, Dempsey EM. Bedside detection of low systemic flow in the very low birth weight infant on day 1 of life. Eur J Pediatr 2009;168:809–13.
  • 34. Urine Output
  • 35. Lactate
    •  Blood Lactate ≠ Lactic Acidosis
    • Cause of  lactate production in neonates:
      • Anaerobic metabolism (e.g. circulatory failure)
      • Increased glycogenolysis
      • Administration of sympathicomimetic drugs
      • Inborn errors of metabolism.
  • 36. Lactate
    • Elevated lactate may be associated with:
      • Normal pH, acidosis, alkalosis
      • Normoxia, hypoxia or anoxia
    • Deshpande and Platt, 1997: 9
      • There was no correlation between common acid-base parameters such as pH, base excess, bicarbonate concentrations and blood lactate concentrations
    9 Deshpande SA, Platt MP. Association between blood lactate and acid–base status and mortality in ventilated babies. Arch Dis Child Fetal Neonatal Ed 1997;76: F15–20.
  • 37. Lactate
    • Despite circulatory insufficiency, lactate may not increase when :
      • Lactate clearance is in balance with lactate production
      • Oxygen delivery meets the oxygen demand in the tissues by increased oxygen extraction
    • Lactate may accumulate locally and remain undetectable until perfusion improves
  • 38. Lactate
    • Miletin et al, 2009: 8
    • Serum lactate ≥ 2.8 mmol/l has sensitivity of 100% and specificity 60% for detecting low flow states.
    8 Miletin J, Pichova K, Dempsey EM. Bedside detection of low systemic flow in the very low birth weight infant on day 1 of life. Eur J Pediatr 2009;168:809–13.
  • 39. Lactate
  • 40. Central–peripheral temp. difference (CPTd)
    • Osborn et al, 2004: 3
    • There was no correlation between CPTd and SVC flow
    3 Osborn DA, Evans N, Kluckow M. Clinical detection of low upper body blood flow in very premature infants using blood pressure, capillary refill time, and central–peripheral temperature difference. Arch Dis Child Fetal Neonatal Ed 2004;89: F168–73.
  • 41. Central–peripheral temp. difference (CPTd)
  • 42. Acid–base balance
    • Kluckow and Evans, 2001: 10
    • No correlation between low SVC flow and pH or base excess
    10 Kluckow M, Evans N. Low systemic blood flow and hyperkalemia in preterm infants. J Pediatr 2001;139:227–32.
  • 43. Venous oxygen saturation (SvO 2 )
    • Mixed SvO 2 represents the oxygen reserve after tissue oxygen extraction
    • SvO 2 depends on:
      • Arterial O 2 concentration
      • O 2 consumption
      • Cardiac output
      • Hb concentration
    • Main PA is most optimal site for mixed venous blood sampling
  • 44.
    • In NB, we can measure central SvO 2
    • Mixed SvO 2 ≠ Central SvO 2
    • Difference is influenced by:
      • Sampling site of central venous blood
      • Presence of left-to-right shunts
      • Incomplete mixing of venous blood
      • Redistribution of blood flow through upper and lower body
      • Level of consciousness (anaesthesia)
      • Myocardial O 2 consumption
    Venous oxygen saturation (SvO 2 )
  • 45. Venous oxygen saturation (SvO 2 )
    • In healthy adults:
    • SVC saturation is 2–3% lower than the true mixed venous saturation
  • 46. Venous oxygen saturation (SvO 2 )
    • In Shock:
      • The relationship between SVC saturation and mixed venous saturation reverses, with the reported difference ranging from 5–18%
    • SVC saturation will typically overestimate Mixed SvO 2 , whereas IVC saturation may underestimate it
    11 Martin J, Shekerdemian LS. The monitoring of venous saturations of oxygen in children with congenitally malformed hearts. Cardiol Young 2009;19:34–9.
  • 47. Venous oxygen saturation (SvO 2 )
    • Hart et al, 2006: 12
    • No linear relationship has been found between IVC SvO 2 , obtained from UVC, and systemic blood flow (SVC flow)
    12 Hart J, Vemgal P, Cocks-Drew S, Harrison C, Andersen C. The relation between inferior vena cava oxygen saturation, superior vena cava flow, fractional oxygen extraction and haemoglobin affinity in sick newborns: a pilot study. Acta Paediatr 2006;95:50–5.
  • 48. Venous oxygen saturation (SvO 2 )
    • de Oliveira et al, 2008: 13
    • Aiming at a central SvO 2 ≥ 70%, improves outcome of pediatric septic shock
    13 de Oliveira CF, de Oliveira DS, Gottschald AF, et al. ACCM/PALS haemodynamic support guidelines for paediatric septic shock: an outcomes comparison with and without monitoring central venous oxygen saturation. Intensive Care Med 2008;34:1065–75.
  • 49. Combination of different clinical hemodynamic variables de Boode. Clinical monitoring of systemic hemodynamics in critically ill newborns. Early Human Development 86 (2010) 137–141
  • 50. Conclusion
    • The clinical assessment of cardiac output by the interpretation of indirect parameters of systemic blood flow is inaccurate , irrespective of the level of experience of the clinician
  • 51. Conclusion
    • Using BP to diagnose low systemic blood flow will consequently mean that too many patients will potentially be undertreated or overtreated , both with substantial risk of adverse effects and iatrogenic damage.
  • 52. Conclusion
    • Combining different clinical hemodynamic parameters enhances the predictive value in the detection of circulatory failure, although accuracy is still limited.
  • 53. Conclusion
    • Variation in time (trend monitoring) might possibly be more informative than individual, static values of clinical and biochemical parameters to evaluate the adequacy of neonatal circulation.
  • 54. THANK YOU