Hyperventilation versus standard ventilation for infants in postoperative care for congenital heart defects with pulmonary hypertension.

Abstract

PURPOSE:

In infants undergoing surgery for cardiac defects with left-to-right shunt, a hyperventilation strategy has been applied to prevent pulmonary hypertensive crisis (PHC). Hyperventilation with a large tidal volume and/or higher airway pressure, however, may be detrimental to the lung. This randomized study compared the effects of hyperventilation versus standard ventilation.

METHODS:

We enrolled 22 infants with a preoperative pulmonary-to-systemic blood pressure ratio of more than 0.7. Hyperventilation, with a tidal volume of 10-12 ml x kg(-1) to keep Pa(CO2) between 30 and 35 mmHg, was randomly applied in 11 patients for 16 h or more. The other 11 patients were randomly assigned to standard ventilation, with a 6- to 8- ml x kg(-1) tidal volume.

RESULTS:

The peak inspiratory pressure was higher (20 +/- 3 vs 18 +/- 2 cmH2O; P = 0.018), and Pa(CO2) (34 +/- 5 vs 42 +/- 7 mmHg; P = 0.003) and positive end-expiratory pressure (3 +/- 0 vs 5 +/- 0; P < 0.0001) were significantly lower in the hyperventilation than in the standard ventilation group. The Pa(CO2)/inspiratory fraction of oxygen Pa(CO2) ratio decreased from 244 +/- 160 mmHg at the onset of postoperative ventilation, to 177 +/- 96 mmHg at 24 h (P = 0.038) in the hyperventilation group, versus a decrease from 240 +/- 89 to 220 +/- 97 mmHg in the standard ventilation group not significant (NS). Serum interleukin (IL)-6 level, measured at 24 h postoperatively, was significantly lower (P = 0.02) in the standard ventilation than in the hyperventilation group, suggesting an attenuated postoperative systemic inflammatory response. A single patient in each group developed PHC.

CONCLUSION:

Hyperventilation may cause lung injury and systemic inflammation in infants with pulmonary hypertension undergoing corrective heart surgery.

• Authors: Takako Umenai, Nobuaki Shime, Satoru Hashimoto
• Journal: Journal of anesthesia (J Anesth) Vol. 23 Issue 1 Pg. 80-6 ( 2009) ISSN: 1438-8359 [Electronic] Japan
• PMID: 19234828 (Publication Type: Comparative Study, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Interleukin-6
• Carbon Dioxide
• C-Reactive Protein
• Oxygen

Topics

• Blood Pressure (physiology)
• C-Reactive Protein (metabolism)
• Carbon Dioxide (blood)
• Cardiac Surgical Procedures (methods)
• Female
• Heart Defects, Congenital (surgery)
• Humans
• Hypertension, Pulmonary (surgery)
• Hyperventilation
• Infant
• Interleukin-6 (blood)
• Male
• Oxygen (blood)
• Pilot Projects
• Positive-Pressure Respiration
• Postoperative Care (methods)
• Pulmonary Circulation
• Pulmonary Gas Exchange
• Respiration, Artificial
• Treatment Outcome