Effect of oxygen on pulmonary hemodynamics and incidence of atrial fibrillation after noncardiac thoracotomy.
OBJECTIVE
The mechanism of postthoracotomy atrial fibrillation (AF) could be related to right ventricular (RV) strain. The effect of oxygen on the occurrence of postoperative AF and on RV function was studied.


METHODS
A prospective, randomized study.


METHODS
A university hospital.


METHODS
Twenty-four noncardiac thoracotomy patients.


METHODS
At the end of the postoperative anesthesia care unit period, the patients were randomly allocated to receive 35% oxygen until either the third (P = prolonged group) or the first postoperative morning (S = short group).


RESULTS
Measurement of hemodynamic variables using a thermodilution pulmonary artery catheter, oxygenation, concentration of plasma atrial natriuretic peptide (ANP) and Holter monitoring were started preoperatively and continued for the 3 postoperative days (PODs). Systolic RV pressure (systolic RVP) and pulmonary vascular resistance (PVR) increased postoperatively only in group S. Major changes in RV performance were not seen with echocardiography or the thermodilution method in any patient. Silent episodes of AF occurred in three patients (25%) in group P and in one patient (8%) in group S (not significant [NS]) without deviations in plasma ANP concentration. On each of the 3 PODs, all patients were exposed to 60% oxygen for 15 minutes. Systolic RVP decreased significantly during the exposure to 60% oxygen only in group S, but not in patients developing AF. Predictive factors for AF were a high preoperative PVR, intraoperative bleeding necessitating volume loading, and elevated systolic RVP immediately after thoracotomy.


CONCLUSIONS
Short episodes of AF occurred irrespective of the length of oxygen therapy. Occurrence of AF could not be explained by changes in RV function.
Bäcklund
M
M
Department of Anaesthesia, Helsinki University Central Hospital, Finland.
Laasonen
L
L
Lepäntalo
M
M
Metsärinne
K
K
Tikkanen
I
I
Lindgren
L
L
D001281:Atrial Fibrillation / Q000209:etiology*; D009320:Atrial Natriuretic Factor / Q000097:blood; D016063:Blood Loss, Surgical; D001810:Blood Volume; D002407:Catheterization, Swan-Ganz; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005544:Forecasting; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D015994:Incidence; D008168:Lung / Q000502:physiology*; D008875:Middle Aged; D010100:Oxygen / Q000097:blood / Q000494:pharmacology; D010101:Oxygen Consumption / Q000502:physiology; D010102:Oxygen Inhalation Therapy; D010952:Plasma Substitutes / Q000627:therapeutic use; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000502:physiology; D013815:Thermodilution; D013908:Thoracotomy / Q000009:adverse effects; D014655:Vascular Resistance / Q000502:physiology; D018497:Ventricular Dysfunction, Right / Q000209:etiology; D016278:Ventricular Function, Right / Q000502:physiology; D017725:Ventricular Pressure / Q000502:physiology
D010952:Plasma Substitutes; D009320:Atrial Natriuretic Factor; D010100:Oxygen