HEART LESIONS & PHYSIOLOGY
A hole between the atria.
What is an ASD (atrial septal defect)?
This non-invasive monitor is standard in the ICU but may be less reliable in patients with poor perfusion or certain shunt lesions.
What is pulse oximetry, or SpO₂?
This pressure, determined by PEEP, inspiratory pressure, and I-time, can decrease venous return and cardiac output if set too high.
What is mean airway pressure?
This test provides pH, PaO₂, and PaCO₂ and is often drawn from an arterial line.
What is an arterial blood gas (ABG)?
After cardiac surgery, this common lung problem shows up as patchy or lobar collapse on x‑ray and often improves with recruitment and positioning.
What is atelectasis?
A large VSD causes a left‑to‑right shunt, which primarily increases blood flow to this circulation.
What is the pulmonary circulation (lungs)?
In many single-ventricle or ductal-dependent lesions, we intentionally avoid 100% saturation and instead target this approximate SpO₂ range to balance Qp:Qs.
What is 75–85%
In a fragile cardiac patient, a sudden drop in blood pressure after a PEEP increase is most likely due to this hemodynamic effect.
What is decreased venous return and reduced cardiac output?
This non-invasive monitoring technology is often used during and after cardiac surgery to trend regional brain or somatic oxygenation.
What is near-infrared spectroscopy, or NIRS?
These drains placed after cardiac surgery can affect lung expansion and must be considered when assessing breath sounds and chest x-rays.
What are chest tubes?
This ductal-dependent lesion requires a patent ductus arteriosus to provide systemic blood flow and often presents with shock when the ductus closes.
What is hypoplastic left heart syndrome, or HLHS?
This value is the primary indicator of oxygenation and is often interpreted alongside SpO₂ in cyanotic heart disease.
What is PaO₂?
Hyperventilating a patient (dropping PaCO₂ too low) generally does this to PVR, which can be harmful in some single ventricle patients.
What is it decreases PVR, increasing pulmonary blood flow and potentially stealing flow from the systemic circulation?
A rising lactate and dropping mixed venous saturation (SvO₂) together suggest this overall issue with systemic circulation.
What is decreased systemic perfusion or low cardiac output?
On a chest X‑ray, this post‑op complication appears as blunting of costophrenic angles or large opacities and can cause decreased breath sounds.
What is a pleural effusion?
In single ventricle physiology (e.g., Norwood), the same ventricle supplies both pulmonary and systemic blood flow. We call these two flows by these abbreviations.
What are Qp (pulmonary blood flow) and Qs (systemic blood flow)?
In a large left‑to‑right shunt with pulmonary overcirculation, high FiO₂ can further lower this vascular resistance, driving more flow to the lungs.
What is pulmonary vascular resistance (PVR)?
In a patient with pulmonary undercirculation (e.g., TOF with significant RV outflow obstruction), your vent strategy should support oxygenation by adjusting these two settings carefully.
What are FiO₂ (increase as needed for sats) and PEEP (use moderate levels to recruit without significantly dropping venous return)?
In a mixing lesion, SpO₂ alone may not fully describe oxygenation. This value tells you the actual partial pressure of oxygen in arterial blood.
What is PaO₂?
Inhaled nitric oxide (iNO) primarily lowers pressure in this vascular bed and is delivered through this route.
What is the pulmonary circulation, delivered via inhalation into the lungs?
In a Glenn circulation, systemic venous blood from the upper body drains directly into this structure without passing through the ventricle first.
What is the pulmonary artery (via the superior vena cava–to–pulmonary artery connection)?
One lesion or situation where your team might intentionally accept SpO₂ in the mid‑70s to mid‑80s, and briefly say why.
Single ventricle/Norwood or Glenn patient, because lower sats help keep Qp and Qs balanced and preserve systemic perfusion.
A post‑op cardiac child is on pressure control ventilation. You see rising PaCO₂ and low tidal volumes while pressures are unchanged. Name one likely cause and one RT action.
Likely cause: decreased lung compliance (atelectasis, edema) or increased resistance. RT action: perform recruitment maneuvers as appropriate, suction, adjust pressures, or notify team.
This blood level rises when tissues are not getting enough oxygen and is often trended in post-op cardiac kids to assess perfusion.
What is lactic acid
A child on iNO is being weaned. List one sign that the patient is not tolerating the wean and one RT action.
Sign: rising pulmonary pressures, desaturation, increased work of breathing, or hemodynamic instability.
RT action: notify team, consider returning to previous iNO dose, ensure adequate oxygenation and ventilation.