Andersons pediatric cardiology 1856

to make sure that there are no complications of cannulation (e.g., regurgitation of the systemic AV or semilunar valve), evaluate for residual lesions, and make certain that the systemic ventricle is decompressed If there is distention and lack of ejection, the ventricle is unlikely to recover and placement of a vent should be strongly considered Cardiac catheterization while the patient is on mechanical support is helpful to exclude residual lesions and perhaps perform interventional procedures, but hemodynamic calculations are extremely difficult to make under the conditions of ECMO Clinical evidence of ventricular recovery includes the return of normal sinus rhythm and spontaneous cardiac ejection Evidence of recovery usually appears within 1 to 4 days Ideally the patient is weaned from support and observed on either no or minimal flow for a period of time and, if stable, hemodynamics are maintained; then decannulation can be performed For the patient with a partially occluded shunt, the shunt will have to be reopened prior to separation from ECMO Acute Respiratory Failure After Extubation Reintubation within 24 hours of extubation following neonatal palliation for fUVH is not uncommon, reaching as high as 33% a decade or two ago More recently, while somewhat improved, it remains at 10% to 20%.42,105,163 Indeed, tracheostomy use has been reported to be as high as 2% of patients (126 of 5721) in one recent series.171 Common causes of acute respiratory failure after extubation include airway edema, left vocal cord injury, and paralysis of the phrenic nerve Investigations for these problems are typically undertaken following stabilization and reintubation Acute failure to extubate—a primary airway and ventilation issue—must be evaluated differently than the progressive cardiopulmonary failure discussed earlier Injury to the recurrent laryngeal nerve will result in vocal cord dysfunction (VCD) VCD after pediatric cardiovascular surgery is associated with ineffective cough, impaired clearance of airway secretions, and difficulty in maintaining lung volume, which can contribute to early respiratory failure after extubation VCD can result in significant feeding problems and a higher risk of aspiration Most injuries involve the left recurrent laryngeal nerve and can occur in up to two-thirds of patients undergoing arch procedures such as the Norwood procedure Management includes feeding evaluation and a modified feeding regimen sometimes including the avoidance of oral feeds with either a nasogastric tube or gastrostomy tube In the Norwood population, VCD adds to length of stay in the CICU Recovery of VCD is seen in about 75% of surviving patients after a year.172–174 Injury to the phrenic nerve may occur during cardiac surgery and will result in paralysis of the diaphragm This is a common cause of failure of extubation Although phrenic nerve injury occurs at the time of surgery, progressive muscle atrophy and loss of tone take several days to develop; as a consequence, the patient may be extubated and may appear well until diaphragmatic function worsens Eventually paradoxic motion of the paralyzed diaphragm occurs, impairing respiratory mechanics The patient will develop tachypnea, hypercapnia, and accessory respiratory muscle use The chest x-ray will show progressive elevation of the affected diaphragm The diagnosis can be confirmed by ultrasound or fluoroscopy Ultimately the patient may need noninvasive ventilatory support or reintubation and mechanical ventilation Although recovery of nerve and diaphragmatic function is common, the time course is typically months, and failure to wean from even noninvasive respiratory support is a generally accepted indication for diaphragmatic plication Typically, a seventh interspace posterolateral thoracotomy is performed on the affected side The diaphragm is plicated with a series of sutures The aim is to create a taut diaphragm that will not move paradoxically and will permit the contralateral healthy diaphragm to change intrathoracic volume and allow for effective ventilation Most patients benefit from plication and can be extubated within a day or two of the procedure Plication does affect ultimate diaphragmatic recovery.175–177 Evaluation and Management of Failure to Progress Although center-specific, the progression of neonates following palliation for univentricular heart disease should generally follow a predictable pattern depending on the exact surgical procedure, comorbidities, and potential systemic limitations.14,105 Centers should establish reliable benchmarks for progression (e.g., sternal closure, weaning from vasoactive medications, timing of extubation, progression to full enteral nutrition) Any deviation from the expected course should prompt early investigation Commonly accepted deviations from the typical course are summarized in Box 71.4 Box 71.4 Common Clinical Presentations of “Failure to Progress” ■ Persistent borderline hemodynamics ■ Persistent hypoxemia ■ Persistent need for mechanical ventilation ■ Persistent fluid overload ■ Inability to tolerate full enteral nutrition ■ Poor weight gain The most common reasons for failure to progress is a borderline hemodynamic profile, a persistent low cardiac output state, or hemodynamic deterioration upon extubation These conditions should trigger prompt evaluation clinically by echocardiography and, if necessary, cardiac catheterization If there is any suspected anatomic burden or coronary abnormality, or if no clearly identifiable cause is present, early postoperative cardiac catheterization should be strongly considered We have found it helpful to convene a multidisciplinary discussion between the cardiac surgeon, cardiac intensive care physician, imaging team, and interventional cardiologist prior to any planned diagnostic or interventional procedure Data suggest that early postoperative catherization yields important information regarding modifiable residual anatomic disease, much of which can be treated during the same catheterization178–180 in more than 70% of cases Despite historical biases to the contrary, early catheter-based interventions can be performed with minimal complications Sometimes chronic respiratory failure is the reason for failure to progress Failure to wean from invasive or noninvasive mechanical ventilation should first prompt a thorough investigation into a cardiac etiology; any residual lesions should be addressed if possible Direct laryngoscopy of the vocal cords, trachea, and bronchi is frequently helpful even if normal Fluoroscopy on sonography of the diaphragm during spontaneous ventilation should be performed for patients who fail to wean from mechanical ventilation; if diaphragmatic paralysis is