I understand that it may be a long time ago you had issues w this baby but I would point out couple of things. Hope you weathered the storm and baby survived. It appeared that from the beginning baby had poor chance. It is important to have good recruitment of the lung before you give surfactant. You dont want it to go only to opened alveoli as the ones closed will be very stiff and eventually end up w PIEs. Undoubtedly Jet is superior to HFOV for PIEs. Jet doesn’t ventilate PIE alveoli allowing them to heal. Ask Dr. Keszler for advices when in question. Next, when you cant oxygenate, like last few CXR shown, and kid is hyperexpanded you are decreasing preload and at the same time obstructing pulmonary flow. You have to drop MAP on HFOV. You need to learn POCUS to look at the heart filling while managing tough cases like this. Also lung US helps a lot. Read Australian and McNamara studies on POC ECHO as well as Kurepa et al. paper on lung US. Finally using higher or lower Hz depends on each baby. See what works for your kid. Remember CXR is just one quick shot in time. All the best.