What's happening during Shock, and what do NICU Nurses need to know?

September is always a special month for me, did you know its NICU Awareness Month? Every year, this month gives me a moment to pause and reflect on why I’m so grateful to be part of this extraordinary community.

I still remember the very first time I walked into a NICU as a nursing student. I had no idea this world even existed. But watching the resilience of those tiny babies, the strength of their families, and the dedication of the nurses around me lit a fire in me that has never gone out. From that day forward, I knew this was my calling.

Since then, I’ve been shaped by the NICU in ways I never could have imagined. It’s taught me patience, kindness, and the importance of the little things—because in the NICU, something as small bringing the hands to the face can have lifelong impact. It’s shown me what true love and perseverance look like, through families who show up day after day, giving everything for their babies.

Most of all, I’m grateful for the community—the NICU nurses who came before me and taught me, the colleagues who inspire me daily, and the families who trust us with their most precious little ones. If I had to sum it up, the NICU is about love, strength, and community.

💜 This NICU Awareness Month, I want to say thank you. Thank you for everything you do, for every baby step you take alongside families, and for being part of this mission to provide the very best care.

👉 Share this newsletter with a NICU nurse who inspires you, and let’s celebrate the incredible NICU community together.

Invest in yourself with the Certification Review Course

Neonatal shock remains one of the most challenging conditions we encounter in the NICU. While we often focus on blood pressure as our primary indicator, the underlying physiology is far more complex than a single number can capture.

Neonatal Shock

Shock occurs when oxygen delivery fails to meet tissue demand. In neonates, this presents unique challenges due to developmental differences in cardiovascular physiology. Unlike adults, preterm infants have immature myocardium with limited contractile reserve and underdeveloped autoregulation mechanisms.

The traditional approach of equating hypotension with shock oversimplifies the problem. As recent research demonstrates, many hypotensive neonates maintain adequate organ perfusion through compensatory mechanisms, while others with "normal" blood pressure may have compromised tissue oxygenation.

🔬 Normal Physiology: Oxygen Delivery & Uptake

Under normal conditions, the cardiovascular system’s main job is to deliver oxygen to tissues. Remember, cardiac output (CO) occurs thanks to heart rate (HR) and stroke volume (SV).

CO = HR x SV

The SV is the volume of blood ejected from the left ventricle (LV) and it is influenced by preload, contractility, and afterload.

• Preload: the volume of blood that fills a newborn's heart ventricles at the end of the heart's resting phase (diastole), just before the heart muscle contracts

• Contractility: the strength and vigor of a newborn's heart muscle contraction

• Afterload: the pressure or resistance that a newborn's heart must overcome to pump blood out of the ventricles and into the rest of the body

Image credit: FACMedicine

It doesn't end there....

Of course we care about cardiac output, but why? The heart pumps blood in order for it to carry oxygen to the tissues. Oxygen delivery (DO₂) depends on cardiac output and arterial oxygen content (CaO₂). C\

.Oxygen Delivery (DO₂) = Cardiac Output × Arterial Oxygen Content (CaO₂)

Another important concept, is oxygen consumption. How much oxygen is the tissue using to maintain normal metabolism?

• Oxygen Consumption (VO₂) stays stable until oxygen delivery drops below a critical threshold.

• When delivery can’t keep up, tissues increase oxygen extraction. Once that maxes out, metabolism shifts from aerobic (efficient ATP production) to anaerobic, producing lactic acidosis.

⚠️ What Happens During Shock?

Shock develops when tissue oxygen demand exceeds supply. Early on, the neonate compensates with tachycardia, vasoconstriction, and preferential blood flow to vital organs (heart, brain, adrenal glands). But as compensation fails, perfusion drops, anaerobic metabolism takes over, and lactate rises.

RNC tips:

• Neonates can only really increase their CO by increasing their HR

• increasing lactate is a hallmark sign of inadequate tissue oxygenation

In neonates, this process is even more complex:

• Transitional circulation (open ductus arteriosus, immature myocardium) alters normal physiology

• Prematurity further limits the heart’s ability to increase stroke volume, making cardiac output heavily rate-dependent

• Organ immaturity means subtle changes in preload, afterload, or contractility can quickly tip the balance and overwhelm the heart.

👩🏻‍⚕️Clinical Assessment Beyond Blood Pressure

Effective shock management requires comprehensive hemodynamic assessment:

• Tissue perfusion markers including lactate levels and capillary refill

• Organ-specific perfusion assessment (NIRS, urine output)

• Volume status evaluation

• Cardiac output evaluation through functional echocardiography

Recent evidence suggests that isolated hypotension without signs of poor perfusion may not require immediate intervention, particularly when cardiac output compensates for decreased vascular resistance.

📚Evidence-Based Treatment Approaches

Current research highlights several important considerations:

Volume Expansion: Multiple studies question the routine use of fluid boluses in preterm infants. Evidence suggests limited benefit and potential harm, including increased risk of intraventricular hemorrhage.

Vasopressor Selection: The choice between dopamine, epinephrine, and other agents should be guided by the underlying pathophysiology.

For example:

• Dopamine may be preferred when both inotropic and vasopressor effects are needed

• Epinephrine might be superior for pure myocardial dysfunction

• Vasopressin could be considered for vasodilatory shock

Corticosteroids: Low-dose hydrocortisone has shown efficacy in vasopressor-resistant hypotension, particularly in extremely preterm infants with relative adrenal insufficiency.

👶The Importance of Individualized Care

Perhaps the most critical takeaway from current research is the need for individualized assessment. Population-based blood pressure norms serve as guidelines, but each patient requires comprehensive evaluation of their hemodynamic status. The goal is not simply to normalize blood pressure, but to ensure adequate oxygen delivery to vital organs.

As NICU nurses, understanding these physiological principles helps us advocate for appropriate monitoring, recognize when intervention is truly needed, and support evidence-based treatment decisions. The complexity of neonatal shock demands sophisticated assessment skills and collaborative care approaches.

Ready to deepen your understanding of neonatal shock and vasoactive medications?

I'm so excited for my upcoming mini-course: "Neonatal Shock & Vasoactive Drugs: Advanced Concepts for NICU Nurses." This comprehensive course will cover:

• Detailed shock pathophysiology

• Evidence-based assessment techniques

• Pharmacology of vasoactive medications

• Case-based learning scenarios

• Latest research applications

The full course won't be available until October 18, 2025, but you can pre-order the course today!

P.S. If you pre-order, you will receive some bonus materials to help you at the bedside before the full course is out!

I'm Ready! Click Here to Pre-Order

Missed my other newsletters? Click here to read them!

Ready to simplify your studying and finally feel confident? Let's Study Together! Join my Certification Course

References:

Lakshminrusimha, S., Seri, I., & Noori, S. (2024). Pathophysiology and etiology of neonatal shock. In R. A. Polin & S. H. Abman (Eds.), Fetal and neonatal physiology (6th ed.). Philadelphia, PA: Elsevier .

Noori, S., Seri, I., & Kluckow, M. (2024). Cardiovascular compromise in the newborn infant. In R. A. Polin & S. H. Abman (Eds.), Fetal and neonatal physiology (6th ed.). Philadelphia, PA: Elsevier .

Noori, S., Friedlich, P. S., & Seri, I. (2022). Pathophysiology of shock in the fetus and neonate. In R. A. Polin & S. H. Abman (Eds.), Fetal and neonatal physiology (5th ed.). Philadelphia, PA: Elsevier .

Kumar, V. K., Pandita, A., Reddy, V. V., & Thakur, D. (2025). Neonatal shock: Current dilemmas and future research. Children, 12(2), 128. https://doi.org/10.3390/children12020128