The effect of a pediatric heat and moisture exchanger on dead space in healthy pediatric anesthesia

다국어 초록 (Multilingual Abstract)

Background: Heat and moisture exchangers (HME) are often used to maintain humidity of breathing circuits during anesthesia. It is also known to increase dead space ventilation in respiratory distress syndromes. However, the effect of a pediatric HME in healthy pediatric patients has not yet been clarified. The purpose of this study was to evaluate the effect of a pediatric HME on dead space in healthy pediatric patients during anesthesia.
Methods: 20 ASA physical class I pediatric patients, without respiratory impairment, who underwent elective surgery for inguinal hernia or hydrocele with general anesthesia were enrolled. Fifteen minutes after ventilation with and without pediatric HME (internal volume of 22 ml), hemodynamic variables, end tidal CO2, minute volume and airway pressure were measured, and arterial blood sampling was conducted simultaneously.
Results: The removal of pediatric HME decreased PaCO2 significantly from 46.1 ± 6.9 mmHg to 37.9 ± 4.3 mmHg (P < 0.001) and increased the pH from 7.32 to 7.37 (P < 0.001). The differences between PaCO2 with and without HME (Δ PaCO2) were significantly correlated with weight (P < 0.001, β1 = -0.749) and age (P = 0.002, β1 = -0.623).
Conclusions: The use of a pediatric HME significantly increased PaCO2 in healthy pediatric patients that was inversely proportional to weight and age. The use of pediatric HME should be carefully considered in small pediatric patients.

다국어 초록 (Multilingual Abstract)

Background: Heat and moisture exchangers (HME) are often used to maintain humidity of breathing circuits during anesthesia. It is also known to increase dead space ventilation in respiratory distress syndromes. However, the effect of a pediatric HME in healthy pediatric patients has not yet been clarified. The purpose of this study was to evaluate the effect of a pediatric HME on dead space in healthy pediatric patients during anesthesia.
Methods: 20 ASA physical class I pediatric patients, without respiratory impairment, who underwent elective surgery for inguinal hernia or hydrocele with general anesthesia were enrolled. Fifteen minutes after ventilation with and without pediatric HME (internal volume of 22 ml), hemodynamic variables, end tidal CO2, minute volume and airway pressure were measured, and arterial blood sampling was conducted simultaneously.
Results: The removal of pediatric HME decreased PaCO2 significantly from 46.1 ± 6.9 mmHg to 37.9 ± 4.3 mmHg (P < 0.001) and increased the pH from 7.32 to 7.37 (P < 0.001). The differences between PaCO2 with and without HME (Δ PaCO2) were significantly correlated with weight (P < 0.001, β1 = -0.749) and age (P = 0.002, β1 = -0.623).
Conclusions: The use of a pediatric HME significantly increased PaCO2 in healthy pediatric patients that was inversely proportional to weight and age. The use of pediatric HME should be carefully considered in small pediatric patients.

참고문헌 (Reference)

1 Iotti GA, "Unfavorable mechanical effects of heat and moisture exchangers in ventilated patients" 23 : 399-405, 1997

2 Campbell RS, "The effects of passive humidifier dead space on respiratory variables in paralyzed and spontaneously breathing patients" 45 : 306-312, 2000

3 Hinkson CR, "The effects of apparatus dead space on PaCO2 in patients receiving lung-protective ventilation" 51 : 1140-1144, 2006

4 Poopalalingam R, "The effect of heat and moisture exchanger and gas flow on humidity and temperature in a circle anaesthetic system" 43 : 563-565, 2002

5 Boyer A, "Small dead space heat and moisture exchangers do not impede gas exchange during noninvasive ventilation: a comparison with a heated humidifier" 36 : 1348-1354, 2010

6 Lindahl SG, "Relationship between invasive and noninvasive measurements of gas exchange in anesthetized infants and children" 66 : 168-175, 1987

7 Rich GF, "Is distal sampling of end-tidal CO2 necessary in small subjects?" 73 : 265-268, 1990

8 Primatesta P, "Inguinal hernia repair: incidence of elective and emergency surgery, readmission and mortality" 25 : 835-839, 1996

9 Le Bourdellès G, "Comparison of the effects of heat and moisture exchangers and heated humidifiers on ventilation and gas exchange during weaning trials from mechanical ventilation" 110 : 1294-1298, 1996

10 Chau A, "Beware the airway filter: deadspace effect in children under 2 years" 16 : 932-938, 2006

11 De Robertis E, "Aspiration of dead space allows isocapnic low tidal volume ventilation in acute lung injury. Relationships to gas exchange and mechanics" 27 : 1496-1503, 2001

12 Numa AH, "Anatomic dead space in infants and children" 80 : 1485-1489, 1996