approach to, 484 f–485 f, 487 diagnostic studies for, 488 t–489 t history, 482 –483 physical examination, 483 , 485 –487 , 486 t triage and stabilization, 482 ultrasound for, 489 t gastrointestinal involvement in, 482 hematologic factors, 482 life-saving maneuvers to relieve, 483 t metabolic disturbances and, 482 neck masses and, 317 –318 pathophysiology, 478 respiratory rates, 486 t treatment, 487 , 490 vital sign abnormalities, 485 Respiratory dysfunction, definition, 77 t Respiratory failure, 478 , 949 criteria for, 479 t Respiratory foreign body, 207 , 208 f, 211 –212 Respiratory paralysis, 558 Respiratory syncytial virus (RSV), 102 , 307 –308 , 500 , 572 Respiratory system, 478 –481 Restrictive Cardiomyopathy (RCM), 613 Reticulocyte counts in aplastic crisis, 420 in Diamond–Blackfan syndrome, 418 in hemolysis, 296 in hemolytic anemias, 419 –420 in hypochromic anemia, 419 in iron-deficiency anemia, 417 MCV and, 423 in sickle cell disease, 374 in transient erythroblastopenia, 419 Reticulocyte index, calculation, 423 Reticulocytosis, 420 Retinal artery occlusion, 190 Retinal artery thrombosis, 191