Low- vs high-dose almitrine combined with nitric oxide to prevent hypoxia during open-chest one-lung ventilation.
BACKGROUND
Almitrine combined with inhaled nitric oxide (NO) can prevent hypoxia during one-lung ventilation (OLV). The optimal dose of almitrine that would provide therapeutic advantage with few side-effects during open-chest OLV has not been established.


METHODS
Forty-two patients undergoing thoracotomy were randomly allocated to three groups: placebo, almitrine 4 microg kg(-1) min(-1) and inhaled NO 10 p.p.m. (ALM4+NO), and almitrine 16 microg kg(-1) min(-1) and inhaled NO 10 p.p.m. (ALM16+NO). Gas exchange, haemodynamic and respiratory variables and plasma concentrations of almitrine and lactate were monitored. Measurements were obtained with the patient awake (baseline), after induction of anaesthesia with two-lung ventilation (control 2LV), 20 min after treatment (2LV+T), and then at 10, 20 and 30 min of OLV (OLV10', OLV20' and OLV30') with FI(O2)1.


RESULTS
In the placebo group, OLV impaired Pa(O2) and increased pulmonary shunt [16 (SD 7) kPa and 42 (10)% respectively]. These improved with ALM4+NO [26 (10) kPa and 31 (7)%; P<0.001]. ALM16+NO further improved PaO2) to 36 (13) kPa (P<0.0001) but gave no improvement in the shunt. Mean pulmonary artery pressure was similar in the placebo and ALM4+NO groups [20 (4) vs 23 (5) mm Hg], whereas it was increased in the ALM16+NO group to 28 (8) mm Hg (P<0.01). Plasma concentrations of almitrine and lactate were unaltered by the treatments.


CONCLUSIONS
Low-dose almitrine (4 microg kg(-1) min(-1)) together with inhaled NO significantly improves oxygenation during open-chest OLV, without modifying pulmonary haemodynamics. An increased dose of almitrine (16 microg kg(-1) min(-1)) with inhaled NO further improves arterial oxygenation, but also increases mean pulmonary artery pressure.
Silva-Costa-Gomes
T
T
Department of Anesthesiology, Hospital Universitari del Mar, Institut Municipal d'Investigacions Mèdiques, Universitat Autònoma de Barcelona, Barcelona, Spain.
Gallart
L
L
Vallès
J
J
Trillo
L
L
Minguella
J
J
Puig
M M
MM
D000293:Adolescent; D000328:Adult; D000368:Aged; D015765:Almitrine / Q000008:administration & dosage* / Q000627:therapeutic use; D000886:Anthropometry; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D000860:Hypoxia / Q000209:etiology / Q000517:prevention & control*; D007431:Intraoperative Complications / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000627:therapeutic use*; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods; D013908:Thoracotomy
D009569:Nitric Oxide; D015765:Almitrine; D010100:Oxygen