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Shock and Hypotension in the Newborn Workup

  • Author: Samir Gupta, DM, MRCP, MD, FRCPCH, FRCPI; Chief Editor: Ted Rosenkrantz, MD  more...
 
Updated: Mar 27, 2014
 

Approach Considerations

At this stage, attempt to determine the type of shock (eg, hypovolemic, cardiogenic, maldistributive) because each requires a different therapeutic approach. In neonates who are hypotensively compromised, the authors encourage the early use of a bladder catheter. Hourly urine output is one of the few objective methods of evaluating hypoperfusion that leads to specific organ failure, and its accurate objective measurement can augment clinical decision making.

Obtain the patient’s hematocrit level, electrolyte levels, blood culture, blood gases (for acid/base status), and glucose level as soon as vascular access is obtained. Among laboratory investigations, data supporting the diagnosis of shock include metabolic acidosis on an arterial blood specimen in the face of reasonable oxygenation.

Elevated plasma lactate with a normal pyruvate suggests anaerobic metabolism triggered by tissue hypoxia-ischemia.

Specific studies must be performed to determine the causes (eg, sepsis, cardiac lesions, anemia) and sequelae (eg, renal, hepatic, endocrine) of shock.

Other pertinent tests include the following:

  • Automated Doppler - Automated Doppler provides blood pressure readings through a noninvasive method
  • Manual oscillometric techniques - Manual oscillometric techniques are used for noninvasive blood pressure testing
  • Infant blood pressure testing - Invasive methods for infant blood pressure testing include direct manometry using an arterial catheter and the use of an in-line pressure transducer and continuous monitor

A study by Wahab and Saeed indicated that serum levels of mannose-binding lectin (MBL) can be used to predict the development of sepsis and septic shock, as well as their prognosis, in neonates. In a comparison of 62 newborns with sepsis with 35 controls, the investigators found that MBL levels were lower in the infants with sepsis and were lowest in those with septic shock, this being particularly the case in infants with septic shock who died.[7]

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Blood Gases

Mixed venous blood gases may be more helpful than arterial measurements, because mixed venous blood gases reflect oxygen extraction and waste products at the tissue level. Conversely, arterial blood reflects lung function and the gas composition of blood before it is delivered to the tissues.

Comparison of simultaneous arterial and mixed venous blood gas determinations may be more useful in assessing cardiac output, tissue oxygenation, and acid-base balance.

The value of capillary blood gas determinations is severely limited because they may only reflect diminished perfusion to the periphery and not reflect central perfusion.

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Echocardiography and Doppler Flow Velocimetry

Echocardiography and Doppler flow velocimetry may provide semiquantitative and semiqualitative noninvasive analysis of myocardial function.

Assessment of left ventricular output

Echocardiography is increasingly used as an imaging tool to objectively assess and manage hypotension. The left ventricular output (LVO) can be quantified to guide the management of hypotension.

If the LVO is normal or high and patent ductus arteriosus (PDA) is not evident, a vasopressor (eg, dopamine) can initially be instituted. If a hemodynamically significant PDA is diagnosed, additional treatment should be directed toward the PDA.

If the LVO is low and the left ventricle (LV) is underfilled, volume expansion is the first-line management. If the LVO is normal and the contractility of the LV is impaired, dobutamine should be the initial choice. Additionally, a low LVO with paradoxical movement of the interventricular septum would benefit from dobutamine.

There are noninvasive methods to assess cardiac output now available, which use either Doppler principle or impedance methods to calculate LVO. Echocardiography remains the criterion standard to evaluate cardiac function.

Newer modalities such as functional MRI are being evaluated to assess cardiac function. This technology is promising but is limited to the research findings and is subject to availability of an MRI scanner. It also has the limitation of the inability to perform repeated longitudinal measurements at point of care, such as bedside echocardiography.

Assessment of superior vena cava flow

Superior vena cava (SVC) flow in newborn infants has been reported to be a novel marker of systemic blood flow.[8] Low SVC flow (< 41 mL/kg/min) has been used to diagnose hypotension and to predict long-term outcome.[9]

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Contributor Information and Disclosures
Author

Samir Gupta, DM, MRCP, MD, FRCPCH, FRCPI Professor of Neonatal Medicine, Deputy Director, Research and Development, University of Durham and North Tees University Hospital, UK

Samir Gupta, DM, MRCP, MD, FRCPCH, FRCPI is a member of the following medical societies: British Medical Association, Society for Pediatric Research, European Society for Paediatric Research, Royal College of Paediatrics and Child Health, European Respiratory Society, Royal College of Physicians of Ireland

Disclosure: Nothing to disclose.

Coauthor(s)

Sunil K Sinha, MBBS, MD, MRCP, PhD, FRCP, FRCPCH Director of Neonatal Services, South Cleveland Hospital, UK

Sunil K Sinha, MBBS, MD, MRCP, PhD, FRCP, FRCPCH is a member of the following medical societies: British Medical Association, Royal College of Physicians

Disclosure: Nothing to disclose.

Chief Editor

Ted Rosenkrantz, MD Professor, Departments of Pediatrics and Obstetrics/Gynecology, Division of Neonatal-Perinatal Medicine, University of Connecticut School of Medicine

Ted Rosenkrantz, MD is a member of the following medical societies: American Academy of Pediatrics, American Pediatric Society, Eastern Society for Pediatric Research, American Medical Association, Connecticut State Medical Society, Society for Pediatric Research

Disclosure: Nothing to disclose.

Acknowledgements

David A Clark, MD Chairman, Professor, Department of Pediatrics, Albany Medical College

David A Clark, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Pediatric Society, Christian Medical & Dental Society, Medical Society of the State of New York, New York Academy of Sciences, and Society for Pediatric Research

Disclosure: Nothing to disclose.

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Pharmacy Editor, eMedicine

Disclosure: Nothing to disclose.

References
  1. Schmaltz C. Hypotension and shock in the preterm neonate. Adv Neonatal Care. 2009 Aug. 9(4):156-62. [Medline].

  2. Al-Aweel I, Pursley DM, Rubin LP, et al. Variations in prevalence of hypotension, hypertension, and vasopressor use in NICUs. J Perinatol. 2001 Jul-Aug. 21(5):272-8. [Medline].

  3. Northern Neonatal Nursing Initiative. Systolic blood pressure in babies of less than 32 weeks gestation in the first year of life. Arch Dis Child Fetal Neonatal Ed. 1999 Jan. 80(1):F38-42. [Medline].

  4. Gupta S, Wyllie J. Correlation of Non-invasive Systolic and Mean Blood pressure (BP) Measurements with Echocardiographic Haemodynamic Assessment. Third Congress of the European Academy of Paediatric Societies (EAPS). Copenhagen, Denmark. October 23-26, 2010.

  5. Laughon M, Bose C, Allred E, et al. Factors associated with treatment for hypotension in extremely low gestational age newborns during the first postnatal week. Pediatrics. 2007 Feb. 119(2):273-80. [Medline].

  6. [Guideline] Dellinger RP, Levy MM, Carlet JM, et al. Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008. Intensive Care Med. 2008 Jan. 34(1):17-60. [Medline].

  7. Wahab Mohamed WA, Saeed MA. Mannose-binding lectin serum levels in neonatal sepsis and septic shock. J Matern Fetal Neonatal Med. 2011 Jun 1. [Medline].

  8. Kluckow M, Evans N. Superior vena cava flow in newborn infants: a novel marker of systemic blood flow. Arch Dis Child Fetal Neonatal Ed. 2000 May. 82(3):F182-7. [Medline].

  9. Osborn DA, Evans N, Kluckow M, et al. Low superior vena cava flow and effect of inotropes on neurodevelopment to 3 years in preterm infants. Pediatrics. 2007 Aug. 120(2):372-80. [Medline].

  10. Skinner JR, Milligan DW, Hunter S, et al. Central venous pressure in the ventilated neonate. Arch Dis Child. 1992 Apr. 67(4 Spec No):374-7. [Medline].

 
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Determinants of cardiac function and oxygen delivery to tissues. Adapted from Strange GR. APLS: The Pediatric Emergency Medicine Course. 3rd ed. Elk Grove Village, Ill: American Academy of Pediatrics; 1998:34.
Assisted ventilation newborn –Intubation and meconium aspiration. Video courtesy of Therese Canares, MD, and Jonathan Valente, MD, Rhode Island Hospital, Brown University.
Table 1. Agents Used To Treat Neonatal Shock
Agent Type Agent Initial Dosage Additional Factors
Volume expanders Isotonic sodium chloride solution 10-20 mL/kg intravenous (IV) Inexpensive, available
Albumin (5%) 10-20 mL/kg IV Expensive
Plasma 10-20 mL/kg IV Expensive
Lactated ringer solution 10-20 mL/kg IV Inexpensive, available
Isotonic glucose 10-20 mL/kg IV Inexpensive, available
Whole blood products 10-20 mL/kg IV Limited availability
Reconstituted blood products 10-20 mL/kg IV Use type



O negative



Vasoactive drugs Dopamine 5-20 mcg/kg/min IV Never administer intra-arterially
Dobutamine 5-20 mcg/kg/min IV Never administer intra-arterially
Epinephrine 0.05-1 mcg/kg/min IV Never administer intra-arterially
Hydralazine 0.1-0.5 mg/kg IV every 3-6 h Afterload reducer
Isoproterenol 0.05-0.5 mcg/kg/min IV Never administer intra-arterially
Nitroprusside 0.5-8 mcg/kg/min IV Afterload reducer
Norepinephrine 0.05-1 mcg/kg/min IV Never administer intra-arterially
Phentolamine 1-20 mcg/kg/min IV Afterload reducer
Milrinone 22.5-45 mcg/kg/h continuous IV infusion (ie, 0.375-0.75 mcg/kg/min) Afterload reducer in cardiac dysfunction; decrease dose with renal impairment
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