orthodeoxia

orthodeoxia

 [or″tho-de-ok´se-ah]
accentuation of arterial hypoxemia in the erect position.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

or·tho·de·ox·i·a

(ōr'thō-dē-oks'ē-ă),
Fall in arterial blood oxygen on assuming the upright posture. Usually caused by right-to-left cardiac or vascular shunting with a posturally induced fall in left-sided pressure permitting a corresponding gradient across the shunt.
Farlex Partner Medical Dictionary © Farlex 2012

or·tho·de·ox·i·a

(ōr'thō-dē-oks'ē-ă)
Fall in arterial blood oxygen on standing upright.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
Marked orthodeoxia was demonstrated; the Fi[O.sub.2] required to achieve fixed Sp[O.sub.2] rapidly fell from 0.66 to 0.46 upon moving from a semirecumbent to supine posture (Figure 4); however, a test-dose of methylene blue did not improve oxygenation.
Platypnoea-orthodeoxia is an unusual phenomenon characterised by positional dyspnoea (platypnoea) and hypoxaemia (orthodeoxia) exacerbated in the sitting position/ improved in the supine position.
The most evident symptom of HPS is dyspnea; however, other clinical manifestations, more commonly seen in this syndrome, despite not specific for it, are platypnea (increased shortness of breath while sitting up from prone position), orthodeoxia (decrease in arterial saturation by more than 5% or 4 mmHg in erect position), spider nevi, and clubbing [9].
Platypnea orthodeoxia, defined as dyspnea and hypoxemia when adopting an upright position and resolving during decubitus, has been attributed to PAVMs [4].
There are some typical conditions when PFO can worsen hypoxemia such as valvular PS, Ebstein anomaly, RV myocardial infarction, orthodeoxia platypnoea syndrome, chronic obstructive pulmonary diseases, pulmonary hypertension (primary or secondary).
One unique patient in our study presented with platypnea (dyspnea on standing) and orthodeoxia (hypoxemia on standing) because of pulmonary hypertension from tumor emboli in combination with a patent foramen ovale that created a right-to-left intracardiac shunt and the reduced venous return to the heart on standing left an insufficient amount of unshunted blood to keep him from deoxygenation.
Orthodeoxia, a drop in oxygen saturation associated with vertical posture, is characteristically present in HPS, but not in porto-pulmonary hypertension, which is much more serious, but thankfully a much less common complication of PHT in childhood.
(3) Pulmonary symptoms include dyspnea, fatigue, cyanosis, and orthodeoxia (decreased arterial oxygen content while upright), all due to right-to-left shunting of blood through the pulmonary AVM.
Most common pulmonary symptom is dyspnea, which may accompany platypnea, and/or orthodeoxia. Platypnea and orthodeoxia are not pathognomonic for HPS.
Platypnea orthodeoxia (PO) is an uncommon presentation of an underlying disorder consisting of hypoxemia and dyspnea upon assuming an upright position and is relieved by decubitus [1].
Several days after extubation, hypoxemia with wide A-a gradient (622 mmHg while receiving 100% FiO2 via non-rebreathing mask) and orthodeoxia (SpO2 88% while in the supine position, decreasing to 79% upon assuming and upright posture) were notable.