2.3 Neonatal Cardiac Surgery and Postoperative Care

Neonatal Cardiac Surgery and Postoperative Care

Quick Answer: Neonatal cardiac surgery succeeds or fails in the hours around cardiopulmonary bypass as much as in the operating room. Preoperative work is PGE1 when the duct is required, a balanced Qp:Qs in single-ventricle physiology, treatment of acidosis and hypothermia, and a mixing atrial communication when parallel circulations need one. Postoperative watch-list items are residual lesions, low cardiac output syndrome, bleeding and tamponade, pulmonary hypertension crisis, chylothorax, arrhythmia, infection, and the developmental cost of neonatal bypass. OpenExamPrep teaches timing concepts such as arterial switch and Norwood or hybrid staging at a nursing level—not operative steps and not an endorsement claim.

Surgery is one of the cardiovascular leaves on the current Neonatal CCRN Test Plan. This section stays at the crib: what you stabilize, what you watch after the sternotomy, and which numbers change your call to the surgeon.

Preoperative stabilization is the first operation

A neonate does not become “surgical” only when the consent is signed. The preoperative hours decide whether the myocardium, kidneys, and brain enter the operating room already injured.

Ductal-dependent infants stay on PGE1 with a secure intravenous path (UVC or a reliable peripheral or central line that will not infiltrate unnoticed). Apnea surveillance is part of the infusion. If the infant is still on a low-dose wean and the lactate climbs from 2 to 5 mmol/L while femorals fade, the problem is the lesion and the closing duct, not a “need for more volume” as the only thought.

Single-ventricle and mixing infants need a balanced circulation. Many units write saturation targets in the 75–85% range for HLHS before Norwood. Free-flow oxygen, hypocapnia, and a hematocrit that is allowed to drift very low all drop PVR and can produce pulmonary overcirculation with systemic and coronary steal. Follow the written target; if the infant is 50% and bradycardic, you still resuscitate.

Metabolic hygiene is not optional. Keep core temperature in the 36.5–37.5 °C band unless a specific cooling protocol is in effect. Treat hypoglycemia (many units intervene below 40–50 mg/dL in the first day). Correct a base deficit that reflects hypoperfusion while you restore oxygen delivery—do not treat a number with bicarbonate while the duct is closed and the gut is ischemic. NPO status, prostaglandin continuity, prostaglandin-compatible lines, prostaglandin-aware transport, and a recent echocardiogram that answers mixing and arch questions are the preoperative checklist.

Balloon atrial septostomy, when needed for TGA with a restrictive FO, is preoperative work, not a postoperative afterthought. After septostomy, watch saturations for a new mixing floor (often a jump from the 50s–60s toward the 70s–80s if the hole is adequate), rhythm, and groin or umbilical catheter sites.

Transport to a cardiac center is a systems task: PGE1 that cannot interrupt, airway plan for prostaglandin apnea, glucose and thermal control, and a receiving team that already knows whether this is shock, cyanosis, or obstructed veins.

Timing concepts at a nursing level

You do not need the suture sequence. You do need why the calendar looks the way it does.

Arterial switch operation (ASO) for TGA is typically performed in the first 1–2 weeks of life. In fetal life the LV faces the high-resistance systemic/placental circuit (the PA arises from the LV in TGA, but fetal PVR is high). After birth the LV quickly “deconditions” as PVR falls. Switching the great arteries too late leaves an LV that cannot face postnatal SVR. Late-presenting TGA may need LV retraining (for example a pulmonary-artery band) before switch—know that the delay exists, not how to band.

Norwood (Stage I) for HLHS is a neonatal reconstruction: the PA is used to rebuild a systemic outflow, an atrial septectomy lets the pulmonary veins empty into the single ventricle, and pulmonary blood flow is provided by a modified Blalock–Taussig shunt or a Sano (RV-to-PA) conduit. Timing is usually in the first week once the infant is metabolically stabilized, not delayed for weeks of “watchful waiting” on a closing duct.

Hybrid strategies (PDA stent plus bilateral pulmonary-artery bands, with or without an atrial intervention) are used when a full neonatal bypass reconstruct is judged too high-risk—extreme prematurity, intracranial hemorrhage, or a center pathway. Nursing implication: the infant still has a duct that must stay open (now stented) and lungs that can be banded too tightly (cyanosis) or too loosely (overcirculation).

Obstructed TAPVR is repaired when recognized, often as an emergency, because delay is pulmonary edema and acidosis. Critical coarctation is repaired in the neonatal period once PGE1 has restored lower-body perfusion and the infant has been resuscitated. TOF may be a complete neonatal repair or a staged shunt, depending on pulmonary-artery size and center practice—your job is cyanosis, spells, and shunt murmur after a staged approach, not choosing the suture line.

Residual lesions are the first postoperative diagnosis to exclude

When an infant does not wean as expected, ask whether the anatomy is still wrong. After ASO: coronary kinking or occlusion (sudden ST change, sudden collapse, unexplained rise in troponin if your unit draws it). After Norwood: residual arch obstruction (upper-to-lower body gradient, hypertension in the arms, gut and renal hypoperfusion), restrictively small atrial communication, or a shunt that is too small (deep cyanosis) or too large (wide pulse pressure, overcirculation). After VSD or AVSD repair: residual ventricular shunt (loud murmur, failure to wean the ventilator, pulmonary edema). After TOF repair: residual RV outflow obstruction or a residual VSD. Echo and the surgeon’s operative note are data, not decorations.

Low cardiac output syndrome

Low cardiac output syndrome (LCOS) is the expected myocardial slump after neonatal bypass. Capillary leak, myocardial edema, and a stiff ventricle peak commonly around 6–18 hours after coming off bypass—often on the night the infant looked “fine” at handoff. You see rising tachycardia (for example 180–200 in a term postoperative infant), cool extremities, oliguria (less than about 1 mL/kg/h), a climbing lactate, a widening base deficit, and a blood pressure that is only held with escalating vasoactive support.

Milrinone is a frequent first inotrope/vasodilator in this setting because it supports contractility and reduces afterload, including RV afterload when PVR is labile. Catecholamines are added per protocol. Nursing is not the drip recipe; it is recognizing that LCOS is a time-window diagnosis and that tamponade, residual lesion, and arrhythmia can mimic it. A falling chest-tube output plus equalizing filling pressures is not “milrinone failure.”

Delayed sternal closure is a planned treatment for edema, not a complication label. An open chest with a silastic patch means you do not bag-ventilate like a closed thorax, you do not lift or turn without a plan, and you treat the chest as a sterile surgical field. Closure happens when edema recedes and hemodynamics tolerate the sternum coming together—often after 24–72 hours, sometimes longer.

Bleeding and tamponade after sternotomy

Neonatal bypass heparin, immature clotting proteins, and a raw sternal bed make bleeding expected. Track chest-tube output in mL/kg/h. Many teams become concerned when output exceeds about 5–10 mL/kg in an hour or stays high over several hours—use your unit threshold, but do not normalize a tube that suddenly goes dry while the abdomen distends and the blood pressure falls.

Tamponade in a neonate rarely announces itself with a textbook Beck triad. Look for sudden hypotension, narrowing pulse pressure, rising atrial or central venous pressure, equalizing filling pressures, muffled or distant heart sounds if you can hear them, and loss of previously brisk chest-tube drainage (clot). Pulsus paradoxus is hard to appreciate on an arterial line in a ventilated neonate, but a swinging systolic pressure with each mechanical breath plus a rising lactate should make you call for an immediate bedside evaluation. Treatment is evacuation—opening the chest at the bedside if the infant is crashing, not a second bag of crystalloid as the only move.

Pulmonary hypertension crisis after repair

Any infant whose pulmonary vascular bed was already reactive (obstructed TAPVR, late mixing lesions, residual left-atrial hypertension, lung disease) can have a pulmonary hypertension crisis: abrupt rise in PA pressure, RV dilation and failure, desaturation, bradycardia, and a rising central venous pressure. Triggers are pain, agitation, hypoxia, hypercarbia, acidosis, and endotracheal suction. Prevention is anticipatory sedation for suction, pre-oxygenation as ordered, and avoiding a “routine deep suction” culture on a fragile RV.

Response is an emergency algorithm: call for help, hand-ventilate with oxygen as ordered, deepen sedation/analgesia, treat acidosis, and start or uptitrate inhaled nitric oxide per protocol. Sodium bicarbonate and hyperventilation appear in some crisis cards; they are physician-directed tools, not a nurse-only reflex. The conceptual point for this exam is that a post-op desaturation storm can be RV afterload, not “the lungs need a bigger tidal volume.”

Chylothorax, arrhythmia, infection, pain, and the developing brain

Chylothorax follows thoracic-duct injury or high venous pressure. If the infant is enterally fed, the chest tube turns milky. Pleural triglycerides often exceed about 110 mg/dL when chyle is present (your lab may also compare pleural and serum values). Management is chest drainage, a diet that reduces long-chain fat (medium-chain triglyceride formula or total parenteral nutrition), and sometimes octreotide. Watch volume loss, lymphocyte loss, and coagulation—chyle is not just “cloudy fluid.”

Arrhythmia. Junctional ectopic tachycardia (JET) after TOF or VSD repair is a narrow-complex, often incessant tachycardia that is poorly tolerated because atrial contribution is lost. Cooling, sedation, and antiarrhythmics are unit-specific. Complete heart block after VSD or AVSD repair may require pacing; temporary epicardial wires are not decorative. Do not chase every sinus tachycardia of 170 in a painful, febrile infant as JET—but do not ignore a sudden rate of 190 with a flat blood pressure and no P waves you can find.

Infection. Mediastinitis and sternal wound infection present with fever, wound drainage, sternal instability, and a rising CRP days after surgery. Central-line infection is the other postoperative bloodstream story. Delayed sternal closure increases exposure time; sterile technique and line discipline are clinical, not ceremonial.

Pain and sedation. Neonatal sternotomy needs a planned opioid, a muscle-relaxant window if the chest is open, and a weaning plan. Dexmedetomidine is common when units want sedation with less respiratory drive suppression. Withdrawal (sweating, yawning, diarrhea, tachycardia, sneezing) appears as infusions wean; score and treat rather than labeling the infant “septic” as the only thought.

Neurodevelopment. Deep hypothermic circulatory arrest, cardiopulmonary bypass, preoperative shock, and residual cyanosis all raise the risk of white-matter injury and later motor or cognitive delay. Nursing contribution is avoiding hypoxia, hypoglycemia, and fever after repair, and making sure the family leaves with a follow-up path—not a promise that bypass is developmentally silent.

Putting a night-shift scenario together

A 3.2 kg infant is 10 hours after arterial switch. Chest-tube output was 8 mL/kg in the first two hours and is now a sudden trickle. Heart rate has climbed from 150 to 188, arterial pressure is 48/38 mm Hg, and the CVP has risen from 6 to 14 mm Hg. Lactate is 4.8 mmol/L. This is tamponade until proven otherwise, not a routine LCOS wean. Compare that with the same infant at 14 hours, tubes draining steadily, warm and well-filled, whose lactate rises from 1.5 to 3.2 mmol/L as urine falls below 1 mL/kg/h: that second picture is the LCOS window and needs support plus a residual-lesion check, not an automatic chest reopening as the first thought.

A 2.6 kg infant 36 hours after TAPVR repair desaturates to 60% during suction, with a rising CVP and a falling arterial pressure. That is a pulmonary hypertension crisis pattern. A 2.8 kg infant on day 8 after Norwood whose chest tube turns milky after feeds is chylothorax until the triglycerides say otherwise.

Exam traps: treating every postoperative slump as “just LCOS” without looking at tubes and filling pressures; bagging an open chest like a closed one; suctioning a reactive pulmonary bed without a sedation plan; calling chyle “transudate” because the infant is on TPN; and describing this OpenExamPrep chapter as official AACN procedure training. It is independent teaching covering surgery as a listed patient problem. Mixed practice items are at /practice/ccrn-neonatal.