To the Editor:

We read with great interest the review by Scharoun et al.1  in which the authors discuss anesthesia management for ophthalmic artery chemosurgery focusing on unexpected respiratory and cardiovascular complications. We address some issues.

The authors advocate systematic and early intravenous administration of epinephrine to treat any decrease in lung compliance, which is the main complication of this procedure. This therapeutic option is questionable. Admittedly, epinephrine dilates bronchial airways.2  However, the main action of this mixed α- and β-adrenergic receptor agonist is on the cardiovascular system, with vasoconstricting, chronotropic, and inotropic effects, also causing several side effects including arrhythmia and systemic hypertension. A decrease in lung compliance can often occur on its own, with neither bradycardia nor hypotension, so cardiovascular therapy is not required and should be used with caution.

Propofol is a therapeutic alternative for the following reasons. First, it provides bronchodilatory effects, acting directly on the smooth muscle of the airway, as well as centrally on γ-aminobutyric acid receptors located in the airway-related vagal neurons in the nucleus of the solitary tract.3,4  Second, because the decrease in lung compliance is caused here by an autonomic reflex, propofol administration, by inducing deeper anesthesia, should inhibit vagal response and thus prevent a steep rise in intrathoracic pressure. This is supported by a systematic review suggesting a relationship between trigeminal reflex and depth of anesthesia during skull base surgery.5  Moreover, a previous study reports that an adequate Bispectral Index target inhibits the oculocardiac reflex during sevoflurane anesthesia for pediatric strabismus surgery.6  Lastly, these respiratory complications do not affect adults but only toddlers and children, whose sympathetic immaturity and increase in vagal tone are more susceptible to autonomic reactions.7,8  This supports the use of hypnotic agents, such as propofol, to prevent and treat the respiratory events. We acknowledge, however, that to date no prospective study has assessed the effect of anesthetic depth on complications during ophthalmic artery chemosurgery.

We agree with the theory that catheter manipulation of the ophthalmic artery may stimulate trigeminal afferents and cause a trigeminal reflex, resulting in respiratory and cardiovascular complications. However, a few questions remain. Although all intracranial arteries are innervated by trigeminal afferents, there are few reports of trigeminal reflex during endovascular procedures involving other intracranial arteries.9  Why does the trigeminal reflex occur particularly in the internal carotid artery and ophthalmic artery? What kind of trigger (e.g., pain stimulus or stretching stimulus) causes these complications and at what threshold? Research focusing on the mechanism of these specific complications could help to prevent or reduce them.

Competing Interests

The authors declare no competing interests.

References

References
1.
Scharoun
JH
,
Han
JH
,
Gobin
YP
:
Anesthesia for ophthalmic artery chemosurgery.
Anesthesiology
2017
;
126
:
165
72
2.
Tanaka
Y
,
Yamashita
Y
,
Horinouchi
T
,
Koike
K
:
Adrenaline produces the relaxation of guinea-pig airway smooth muscle primarily through the mediation of beta(2)-adrenoceptors.
J Smooth Muscle Res
2005
;
41
:
153
61
3.
Gallos
G
,
Gleason
NR
,
Virag
L
,
Zhang
Y
,
Mizuta
K
,
Whittington
RA
,
Emala
CW
:
Endogenous gamma-aminobutyric acid modulates tonic guinea pig airway tone and propofol-induced airway smooth muscle relaxation.
Anesthesiology
2009
;
110
:
748
58
4.
Jin
Z
,
Choi
MJ
,
Park
CS
,
Park
YS
,
Jin
YH
:
Propofol facilitated excitatory postsynaptic currents frequency on nucleus tractus solitarii (NTS) neurons.
Brain Res
2012
;
1432
:
1
6
5.
Meuwly
C
,
Chowdhury
T
,
Sandu
N
,
Reck
M
,
Erne
P
,
Schaller
B
:
Anesthetic influence on occurrence and treatment of the trigemino-cardiac reflex: A systematic literature review.
Medicine (Baltimore)
2015
;
94
:
e807
6.
Yi
C
,
Jee
D
:
Influence of the anaesthetic depth on the inhibition of the oculocardiac reflex during sevoflurane anaesthesia for paediatric strabismus surgery.
Br J Anaesth
2008
;
101
:
234
8
7.
Paques
M
,
Vallée
JN
,
Herbreteau
D
,
Aymart
A
,
Santiago
PY
,
Campinchi-Tardy
F
,
Payen
D
,
Merlan
JJ
,
Gaudric
A
,
Massin
P
:
Superselective ophthalmic artery fibrinolytic therapy for the treatment of central retinal vein occlusion.
Br J Ophthalmol
2000
;
84
:
1387
91
8.
Goto
M
,
Nagashima
M
,
Baba
R
,
Nagano
Y
,
Yokota
M
,
Nishibata
K
,
Tsuji
A
:
Analysis of heart rate variability demonstrates effects of development on vagal modulation of heart rate in healthy children.
J Pediatr
1997
;
130
:
725
9
9.
Meuwly
C
,
Golanov
E
,
Chowdhury
T
,
Erne
P
,
Schaller
B
:
Trigeminal cardiac reflex: New thinking model about the definition based on a literature review.
Medicine (Baltimore)
2015
;
94
:
484
.