JOURNAL ARTICLE

Gas exchange detection of exercise-induced right-to-left shunt in patients with primary pulmonary hypertension

Xing-Guo Sun, James E Hansen, Ronald J Oudiz, Karlman Wasserman
Circulation 2002 January 1, 105 (1): 54-60
11772876

BACKGROUND: Because of high pulmonary vascular resistance in patients with primary pulmonary hypertension (PPH), right atrial pressure may exceed left atrial pressure during exercise, resulting in a right-to-left shunt via a patent foramen ovale (PFO). This shunting would disturb arterial PCO2 and H+ homeostasis if the pulmonary blood were not simultaneously hyperventilated to compensate for the high CO2 and H+ in the shunted blood. This article first hypothesizes and then describes unique changes in gas exchange when right-to-left exercise-induced shunting (EIS) occurs.

METHODS AND RESULTS: Retrospectively, the cardiopulmonary exercise tests of 71 PPH patients were studied. Criteria postulated to document hyperventilation of the pulmonary blood flow due to a right-to-left EIS were (1) an abrupt and sustained increase in end-tidal O2 with a simultaneous sustained decrease in end-tidal CO2; (2) an abrupt and sustained increase in the respiratory exchange ratio; and (3) usually, an associated decline in pulse oximetry saturation. Each patient was evaluated for a PFO with resting echocardiography. The investigators interpreting the gas exchange evidence of EIS were blinded to the echocardiographic readings. Forty-five percent of the patients had demonstrable EIS by gas exchange criteria. Almost all were also positive for a PFO by echocardiography. Using the resting echocardiograph as the reference, the sensitivity, specificity, positive and negative predictive values, and accuracy were all between 90% to 96%.

CONCLUSIONS: Exercise-induced right-to-left shunting can be detected by noninvasive, cardiopulmonary exercise testing in patients with PPH.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
11772876
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"