Letter to the Editor Received: October 27, 2014 Accepted: October 28, 2014 Published online: March 13, 2015
Neonatology 2015;107:312 DOI: 10.1159/000369376
Why Not Use a Surfactant Test for Respiratory Distress Syndrome? Humberto Holmer Fiori Renato Machado Fiori Graduate Program in Medicine, Pediatrics and Child Health, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil
Dear Sir, Bhatia et al. [1] recently demonstrated the usefulness of the stable microbubble test (SMT) to predict the need for ventilation in continuous positive airway pressure (CPAP)-treated preterm infants. In 1979, Pattle et al. [2] first published a study showing that the SMT in amniotic fluid was suitable to evaluate lung maturity in preterm infants, and Chida et al. [3] in 1993 confirmed the value of this test in gastric fluid as well as in amniotic fluid. Nevertheless, the SMT was forgotten until the surfactant and early CPAP era. In 2006, a small study showed the utility of the test to predict the need for surfactant in nonventilated preterm infants [4]. In a recent study, the test showed good sensitivity (94%) and specificity (86%) for the diagnosis of respiratory distress syndrome when performed in gastric fluid [5]. We have introduced the SMT as part of routine care of all very-low-birthweight infants at our service, to assist in the
decision to give early surfactant in symptomatic infants on CPAP. The test is done at the cotside in 5 min, using a drop of gastric fluid. The only equipment required is a simple microscope with 100× magnification, a Neubauer chamber (which is available in any laboratory), and a pipette connected to a rubber cap to produce the bubbles. The technique can be easily learned in a few minutes by any resident or nurse, and its cost is negligible. Another test that has gained popularity among obstetricians is the lamellar body count, traditionally in amniotic fluid, but which can also be performed in gastric fluid. In a randomized trial, Verder et al. [6] tested the lamellar body count in gastric fluid as a guide to give early surfactant to CPAP-treated very preterm infants (less than 30 weeks’ gestation) with respiratory distress syndrome and found only a reduction of oxygen needed at 28 days. We spec-
ulate that even better results might be achieved if surfactant was administered earlier (average time to administration was 2.3 h, and less than 10% received surfactant within 1.5 h). Furthermore, in 23% of infants, the test could not be performed due to viscosity of the gastric fluid. Conversely, the SMT can be performed in practically all infants. While the lamellar body count is also a simple test, it needs to be done in a laboratory setting, which may have been one of the reasons for delay in administering surfactant in the study by Verder et al. [6]. In this respect, the SMT is more convenient, as it can be done at the cotside or even in the delivery room, without delay. In current practice, all very-low-birthweight infants have a gastric tube in place. Why not perform the SMT routinely in these infants if it provides such useful information at practically no cost?
3 Chida S, Fujiwara T, Konishi M, Takahashi H, Sasaki M: Stable microbubble test for predicting the risk of respiratory distress syndrome. II. Prospective evaluation of the test on amniotic fluid and gastric aspirate. Eur J Pediatr 1993;152:152–156. 4 Fiori HH, Fritscher CC, Fiori RM: Selective surfactant prophylaxis in preterm born at ≤31 weeks’ gestation using the stable microbubble test in gastric aspirates. J Perinat Med 2006; 34:66–70.
5 Daniel IWB, Fiori HH, Piva JP, Munhoz TP, Nectoux AV, Fiori RM: Lamellar body count and stable microbubble test on gastric aspirates from preterm infants for the diagnosis of respiratory distress syndrome. Neonatology 2010;98:150–155. 6 Verder H, Ebbesen F, Fenger-Grøn J, Henriksen TB, Andreasson B, Bender L, Bertelsen A, Björklund LJ, Dahl M, Esberg G, Eschen C, Høvring M, Kreft A, Kroner J, Lundberg F, Pedersen P, Reinholdt J, Stanchev H: Early surfactant guided by lamellar body counts on gastric aspirate in very preterm infants. Neonatology 2013;104:116–122.
1 Bhatia R, Morley CJ, Argus B, Tingay DG, Donath S, Davis PG: The stable microbubble test for determining continuous positive airway pressure (CPAP) success in very preterm infants receiving nasal CPAP from birth. Neonatology 2013;104:188–193. 2 Pattle RE, Kratzing CC, Parkinson CE, Graves L, Robertson RD, Gobards GJ, Currie JO, Parsons JH, Sutherland PD: Maturity of fetal lungs tested by production of stable microbubbles in amniotic fluid. Br J Obstet Gynaecol 1979;86:615–622.
© 2015 S. Karger AG, Basel 1661–7800/15/1074–0312$39.50/0 E-Mail [email protected] www.karger.com/neo
Humberto Holmer Fiori Graduate Program in Medicine, Pediatrics and Child Health Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS) Porto Alegre, RS 90619-9000 (Brazil) E-Mail hfiori @ pucrs.br
Downloaded by: NYU Medical Center Library 128.122.253.228 - 5/6/2015 11:34:11 PM
References
Neonatology 2015;107:312 DOI: 10.1159/000369376
Why Not Use a Surfactant Test for Respiratory Distress Syndrome? Humberto Holmer Fiori Renato Machado Fiori Graduate Program in Medicine, Pediatrics and Child Health, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil
Dear Sir, Bhatia et al. [1] recently demonstrated the usefulness of the stable microbubble test (SMT) to predict the need for ventilation in continuous positive airway pressure (CPAP)-treated preterm infants. In 1979, Pattle et al. [2] first published a study showing that the SMT in amniotic fluid was suitable to evaluate lung maturity in preterm infants, and Chida et al. [3] in 1993 confirmed the value of this test in gastric fluid as well as in amniotic fluid. Nevertheless, the SMT was forgotten until the surfactant and early CPAP era. In 2006, a small study showed the utility of the test to predict the need for surfactant in nonventilated preterm infants [4]. In a recent study, the test showed good sensitivity (94%) and specificity (86%) for the diagnosis of respiratory distress syndrome when performed in gastric fluid [5]. We have introduced the SMT as part of routine care of all very-low-birthweight infants at our service, to assist in the
decision to give early surfactant in symptomatic infants on CPAP. The test is done at the cotside in 5 min, using a drop of gastric fluid. The only equipment required is a simple microscope with 100× magnification, a Neubauer chamber (which is available in any laboratory), and a pipette connected to a rubber cap to produce the bubbles. The technique can be easily learned in a few minutes by any resident or nurse, and its cost is negligible. Another test that has gained popularity among obstetricians is the lamellar body count, traditionally in amniotic fluid, but which can also be performed in gastric fluid. In a randomized trial, Verder et al. [6] tested the lamellar body count in gastric fluid as a guide to give early surfactant to CPAP-treated very preterm infants (less than 30 weeks’ gestation) with respiratory distress syndrome and found only a reduction of oxygen needed at 28 days. We spec-
ulate that even better results might be achieved if surfactant was administered earlier (average time to administration was 2.3 h, and less than 10% received surfactant within 1.5 h). Furthermore, in 23% of infants, the test could not be performed due to viscosity of the gastric fluid. Conversely, the SMT can be performed in practically all infants. While the lamellar body count is also a simple test, it needs to be done in a laboratory setting, which may have been one of the reasons for delay in administering surfactant in the study by Verder et al. [6]. In this respect, the SMT is more convenient, as it can be done at the cotside or even in the delivery room, without delay. In current practice, all very-low-birthweight infants have a gastric tube in place. Why not perform the SMT routinely in these infants if it provides such useful information at practically no cost?
3 Chida S, Fujiwara T, Konishi M, Takahashi H, Sasaki M: Stable microbubble test for predicting the risk of respiratory distress syndrome. II. Prospective evaluation of the test on amniotic fluid and gastric aspirate. Eur J Pediatr 1993;152:152–156. 4 Fiori HH, Fritscher CC, Fiori RM: Selective surfactant prophylaxis in preterm born at ≤31 weeks’ gestation using the stable microbubble test in gastric aspirates. J Perinat Med 2006; 34:66–70.
5 Daniel IWB, Fiori HH, Piva JP, Munhoz TP, Nectoux AV, Fiori RM: Lamellar body count and stable microbubble test on gastric aspirates from preterm infants for the diagnosis of respiratory distress syndrome. Neonatology 2010;98:150–155. 6 Verder H, Ebbesen F, Fenger-Grøn J, Henriksen TB, Andreasson B, Bender L, Bertelsen A, Björklund LJ, Dahl M, Esberg G, Eschen C, Høvring M, Kreft A, Kroner J, Lundberg F, Pedersen P, Reinholdt J, Stanchev H: Early surfactant guided by lamellar body counts on gastric aspirate in very preterm infants. Neonatology 2013;104:116–122.
1 Bhatia R, Morley CJ, Argus B, Tingay DG, Donath S, Davis PG: The stable microbubble test for determining continuous positive airway pressure (CPAP) success in very preterm infants receiving nasal CPAP from birth. Neonatology 2013;104:188–193. 2 Pattle RE, Kratzing CC, Parkinson CE, Graves L, Robertson RD, Gobards GJ, Currie JO, Parsons JH, Sutherland PD: Maturity of fetal lungs tested by production of stable microbubbles in amniotic fluid. Br J Obstet Gynaecol 1979;86:615–622.
© 2015 S. Karger AG, Basel 1661–7800/15/1074–0312$39.50/0 E-Mail [email protected] www.karger.com/neo
Humberto Holmer Fiori Graduate Program in Medicine, Pediatrics and Child Health Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS) Porto Alegre, RS 90619-9000 (Brazil) E-Mail hfiori @ pucrs.br
Downloaded by: NYU Medical Center Library 128.122.253.228 - 5/6/2015 11:34:11 PM
References
