UOTW #29 Answer - Core Ultrasound

Diagnosis: Severe Pulmonary Hypertension

This echocardiogram demonstrates profound RV dilation, suspected to be secondary to severe pulmonary hypertension. Despite FiO2 of 100% sats were in the 50’s so inhaled nitric oxide was started to empirically treat the pulmonary hypertension. The patient’s oxygen saturation jumped to 100% after just a few minutes of this treatment regimen. His FiO2 was slowly weaned down before he was transferred to see a pulmonary hypertension specialist.

Signs of pulmonary hypertension on bedside echo include an RV:LV ratio > 1:1 on the apical view, a D-shaped left ventricle on the PSAX view (flattening of the interventricular septum on apical/PLAX view), and tricuspid regurgitation (TR).
The IVC inspiratory collapse percentage can help estimate right atrial pressure (RAP, same as central venous pressure) in the infant population, just as it can in adults.¹ Remember that the 50% IVC collapse cutoff is reliable only in the spontaneously breathing patient. The <50% IVC collapse in this patient predicts a RAP of ~15 mmHg. Absolute IVC size varies in children, so it is not a reliable indicator of RAP.
To estimate right ventricular systolic pressure (RVSP, same as pulmonary artery systolic pressure assuming no obstruction between the PA and RV) you must add your estimated RAP to the pressure gradient you obtain by measuring the maximal TR jet. Here is a handy RVSP calculator to do the hard math for you. An RVSP of < 30 mmHg is normal, although a cutoff of 40 mmHg is considered normal in the obese and elderly.²
In the pediatric population, the most common causes of pulmonary hypertension are idiopathic and congenital heart defects.³
Pediatric patients with acute respiratory distress syndrome have been shown to respond to inhaled nitric oxide as empiric treatment.^4,5 This treatment is especially useful in patients with pulmonary hypertension.

Jone PN, Ivy DD. Echocardiography in Pediatric Pulmonary Hypertension. Front Pediatr. 2014;2:124. [PDF]
McQuillan BM, Picard MH. Clinical correlates and reference intervals for pulmonary artery systolic pressure among echocardiographically normal subjects. Circulation. 2001;104(23):2797-802. [PDF]
Beghetti M, Berger RMF. The challenges in paediatric pulmonary arterial hypertension. European Respiratory Review. 2014;23(134):498–504. [PDF]
Dellinger RP, Zimmerman JL, Taylor RW, Straube RC, Hauser Dl, Criner GJ, Davis K, Hyers TM, Papdakos P. Effects of inhaled nitric oxide in patients with acute respiratory distress syndrome: results of a randomized phase II trial. Crit Care Med. 1998;26:15–23. [PubMed]
Troncy E, Collet JP, Shapiro S, Guimond JG, Blair L, Ducruet T, Francoeur M, Charbonneau M, Blaise G. Inhaled nitric oxide in acute respiratory distress syndrome: a pilot randomized controlled study. Am J Respir Crit Care Med. 1998;157:1483–1488. [PubMed]

One Comment

Dr Srinivas Jakkula says:
December 20, 2014 at 5:19 pm
That the RV and RA are enlarged and the RV is hypertrophied (chronic pressure overload) is quite obvious. Indeed pulmonary hypertension is very likely and the obvious needs to be stated first. What is also evident is that there is pleural effusion and interstitial/extra-vascular lung water (>3 B lines/rockets in one intercostal window) which means that the pulmonary artery occlusion pressure is greater than 18 mmHg, again supporting pulmonary hypertension (unless ofcourse the kid is really unlucky to have a 2nd pathology causing pulmonary capillary endothelial dysfunction and non-cardiogenic pulmonary oedema (ARDS)) . Another thing that is obvious is the obliteration of the LV cavity in systoly suggesting persistent left to right intracardiac shunt in this setting and given that the inter-atrial septum looks a bit suspect, one also needs to interrogate that inter-atrial septum more closely using atleast 2 other views with colour and Doppler mode, as it may give a clue as to the cause of pulmonary hypertension! A novice might also state that there is a pericardial effusion, given the hypoechoeic rim around the RV in the subcostal view, but that would be erroneous as it almost certainly is pericardial fat that is common in this age group and the rim doesn’t extend around the LV .