Dear Editor,
I read with interest the article by Dargaville et al (1), about the
feasibility and potential effectiveness of MIST, i.e. minimally-invasive
surfactant therapy, in preterm infants with respiratory distress syndrome.
Similarly to other recent techniques (2,3), the ultimate goal of MIST is
that of delivering surfactant while avoiding both "standard" tracheal
intubation and mechanical ventilation. The authors have adopted the Horbat
method (4), which implies the use of a narrow-bore vascular catheter to
intubate briefly the trachea, through which surfactant is then instilled
in three-four aliquots.
I have some concerns about considering MIST as a "minimally invasive"
technique. In fact, some components of the procedure do not appear as
marginally invasive as proposed by the authors.
First, laryngoscopy with a blade is an invasive manoeuvre, which may
injury the upper airways and provoke vagal stimulation. Notably, about 35%
of infants suffered bradycardia during the procedure.
Second, insertion of a semi-rigid vascular catheter, with its relatively
sharp rim, may damage the vocal cords and the trachea. Fortunately, no
iatrogenic airway injuries were reported by the authors. However, prior to
insertion, some investigators manually fashioned a slight curvature at the
tip, possibly to ease the catheter positioning and reduce the risk of
perforation. Risk of tearing the trachea could be even higher when dealing
with a "fighting" baby (no premedication were used in this study) or when
people performing the procedure are relatively inexperienced. In this
study, about 20% of the infants required two or more catheterisation
attempts, despite the availability of expert neonatologists.
I believe the intriguing results reported by the authors are related more
to the inherent effect of surfactant, rather than to the delivery method
used. More data must be rigorously collected before considering MIST as a
safe method for surfactant therapy in preterm infants with RDS.
References
1) Dargaville PA, Aiyappan A, De Paoli AG, et al. Minimally-invasive
surfactant therapy in preterm infants on continuous positive airway
pressure. Arch Dis Child Fetal Neonatal Ed 2012 Jun 9. [Epub ahead of
print]
2) G?pel W, Kribs A, Ziegler A, et al. Avoidance of mechanical
ventilation by surfactant treatment of spontaneously breathing preterm
infants (AMV): an open-label, randomised, controlled trial. Lancet
2011;378:1627-34.
3) Finer NN, Merritt TA, Bernstein G, et al. An open label, pilot study of
Aerosurf combined with nCPAP to prevent RDS in preterm neonates. J Aerosol
Med Pulm Drug Deliv 2010;23:303-9.
4) Dargaville PA, Aiyappan A, Cornelius A, et al. Preliminary evaluation
of a new technique of minimally invasive surfactant therapy. Arch Dis
Child Fetal Neonatal Ed 2011;96:F243-8
Conflict of Interest:
None declared
Dear Editor, I read with interest the article by Dargaville et al (1), about the feasibility and potential effectiveness of MIST, i.e. minimally-invasive surfactant therapy, in preterm infants with respiratory distress syndrome. Similarly to other recent techniques (2,3), the ultimate goal of MIST is that of delivering surfactant while avoiding both "standard" tracheal intubation and mechanical ventilation. The authors have adopted the Horbat method (4), which implies the use of a narrow-bore vascular catheter to intubate briefly the trachea, through which surfactant is then instilled in three-four aliquots. I have some concerns about considering MIST as a "minimally invasive" technique. In fact, some components of the procedure do not appear as marginally invasive as proposed by the authors. First, laryngoscopy with a blade is an invasive manoeuvre, which may injury the upper airways and provoke vagal stimulation. Notably, about 35% of infants suffered bradycardia during the procedure. Second, insertion of a semi-rigid vascular catheter, with its relatively sharp rim, may damage the vocal cords and the trachea. Fortunately, no iatrogenic airway injuries were reported by the authors. However, prior to insertion, some investigators manually fashioned a slight curvature at the tip, possibly to ease the catheter positioning and reduce the risk of perforation. Risk of tearing the trachea could be even higher when dealing with a "fighting" baby (no premedication were used in this study) or when people performing the procedure are relatively inexperienced. In this study, about 20% of the infants required two or more catheterisation attempts, despite the availability of expert neonatologists. I believe the intriguing results reported by the authors are related more to the inherent effect of surfactant, rather than to the delivery method used. More data must be rigorously collected before considering MIST as a safe method for surfactant therapy in preterm infants with RDS. References 1) Dargaville PA, Aiyappan A, De Paoli AG, et al. Minimally-invasive surfactant therapy in preterm infants on continuous positive airway pressure. Arch Dis Child Fetal Neonatal Ed 2012 Jun 9. [Epub ahead of print] 2) G?pel W, Kribs A, Ziegler A, et al. Avoidance of mechanical ventilation by surfactant treatment of spontaneously breathing preterm infants (AMV): an open-label, randomised, controlled trial. Lancet 2011;378:1627-34. 3) Finer NN, Merritt TA, Bernstein G, et al. An open label, pilot study of Aerosurf combined with nCPAP to prevent RDS in preterm neonates. J Aerosol Med Pulm Drug Deliv 2010;23:303-9. 4) Dargaville PA, Aiyappan A, Cornelius A, et al. Preliminary evaluation of a new technique of minimally invasive surfactant therapy. Arch Dis Child Fetal Neonatal Ed 2011;96:F243-8
Conflict of Interest:
None declared