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Published on: October 11, 2011
Changes in mean airway pressure during HFOV influences cardiac output in neonates and infants
N Gullberg1, P Winberg, H Selldén
1Pediatric Anesthesia and Intensive Care, Astrid Lindgren Children's Hospital/Karolinska Hospital, S-171 76 Stockholm, Sweden. ninna.gullberg@ks.se
Insights
Changes in mean airway pressure during high-frequency oscillation ventilation (HFOV) affect cardiac output. This study found cardiac output changes with mean airway pressure adjustments in pediatric patients on HFOV.
Area of Science:
- Pediatric Intensive Care
- Cardiopulmonary Physiology
- Mechanical Ventilation
Background:
- Mean airway pressure impacts cardiac output in conventional ventilation.
- The effect of high-frequency oscillation ventilation (HFOV) on cardiac output is not well understood.
Purpose of the Study:
- To investigate the relationship between mean airway pressure and cardiac output in pediatric patients receiving HFOV.
- To compare the effects of HFOV-induced pressure changes on cardiac output with those observed in conventional ventilation.
Main Methods:
- Prospective study in a pediatric intensive care unit involving 14 infants (<1 year, <10 kg) on stable HFOV.
- Mean proximal airway pressure (Paw) was altered (+5 and -3 cmH2O) in the study group (n=9); control group (n=5) had stable parameters.
- Cardiac output was assessed using echocardiography and Doppler at various Paw levels.
Main Results:
- Cardiac output significantly changed with alterations in mean Paw during HFOV (P=0.02).
- The largest decrease in cardiac output was -11% at the highest Paw setting.
- No significant changes in cardiac output were observed in the control group.
Conclusions:
- Mean airway pressure changes during HFOV affect cardiac output, similar to conventional ventilation.
- Observed cardiac output changes were less pronounced than previously reported with conventional mechanical ventilation.
- Further research is needed to fully elucidate these cardiopulmonary interactions during HFOV.
Background:
Changes in mean airway pressure affect cardiac output during conventional positive pressure ventilation. The effect of high-frequency oscillation ventilation (HFOV) on cardiac output is less studied.
Methods:
A prospective study in a university hospital pediatric intensive care unit. Fourteen patients aged <1 year and weighing <10 kg who were on HFOV were included. All patients had been on HFOV for >12 h and were considered to be in a stable condition. In the study group (n = 9) the mean proximal airway pressure (Paw) was increased and decreased by +5 and -3 cmH2O, respectively, from baseline in each patient. Measurements were made at each level including baseline settings between each change. In a control group (n = 5) no changes in ventilatory parameters were made. Cardiac output was assessed with echocardiography and the Doppler technique at each level of Paw and at similar intervals in the control group.
Results:
Cardiac output changed significantly when Paw was changed in the study group (P = 0.02), with the greatest change at the highest Paw at -11% (range: -19 to -9) compared with baseline. We found no significant changes over time in the control group.
Conclusion:
This study shows that CO is affected by changes in mean airway pressure during HFOV in concordance with the known effects of mean airway pressure during conventional positive pressure ventilation. The mean changes are smaller than expected compared with earlier studies of conventional mechanical ventilation. Further studies are needed to better understand these relationships.
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