Pulmonary Hypertension Secondary To CLD: A Cautionary Tale

Abstract

Table 1: Pre and Post re-intubation ventilator setting, FiO2, pH and PCO2The incidence of chronic lung disease (CLD) ranges from 7 to 52% and is highest among extremely premature neonates. Background: CLD increases the risk of developing pulmonary hypertension (PH) secondary to altered angiogenesis and post natal lung growth, and abnormal vasoreactivity. PH especially in the infants requiring prolonged mechanical ventilation contributes to their morbidity and mortality; moreover the management of PH is still being refined. A goal to maintain normal CO and alkalotic pH to decrease PVR, may 2 lead to invasive ventilation and promote other invasive interventions such as tracheostomy, gastrostomy and heavy sedation.We present 4 extreme preterms (GA 26wks in 3 and 24wks in one) with PH associated with CLD. All had severe RDS and Case series: required prolonged ventilation (46, 104, 46 and 85 days respectively), but successfully weaned off to either nasal cannula or CPAP. All had severe pulmonary hypertension diagnosed by ECHO, treated with combination of iNO, Sildenafil, Bosentan and Prostacyclin targeting the 3 pathways of PVR (cGMP, Endothelin and cAMP). All electively re-intubated for invasive ventilation to keep PCO in targeted low range to 2 decrease PVR (day of life at re-intubation 165, 181, 189 and 161 respectively). The institution of mechanical ventilation lead to later escalation of ventilatory support, ventilatory dependency and tracheostomy without significant improvement in PCO , worsening PH and 2 oxygenation. (table1) NICU course was protracted (244, 344, 240, and 315 days). Currently 2/4 are still in chronic care facility, 3 are still ventilator dependent with tracheostomies with chronological age of 1, 2, 1.5 and 5.5 years.Current management of CLD includes permissive hypercapnea and permissive hypoxia, but when associated with PH, Discussion: management is still debated. Animal Studies by Malik and Marshall have shown that PVR is affected by pH alone rather than independent changes in PaCO CLD patients have chronic compensated respiratory acidosis keeping pH close to normal. Combinations of 2. supplemental therapies targeting the PVR have shown to be beneficial.Elective mechanical ventilation in preterm infants with PH associated with CLD should be avoided as it may trigger Conclusion: pulmonary hypertensive crisis with all attendant aforementioned morbidities. The management should be guided by pH in conjunction with medications that alter vascular reactivity and the provision of optimal nutrition to assure adequate somatic/lung growth. Cases with such severe presentation may warrant lung biopsy to exclude developmental lung anomalies. This abstract is funded by: None