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Subglottic stenosis is a common
sequelae of prolonged endotracheal
intubation. Radial expansion balloon
dilation has become commonplace for
stenosis management. This allows for
increased dilation diameters with minimal
tangential shearing forces that could
damage normal respiratory mucosa.
These dilation procedures require
intermittent complete luminal obstruction.
Balloon dilator malfunctions have lead to
prolonged obstruction, resulting in serious
patient complications, including death.
Given the therapeutic value of these
devices, it is imperative to recognize the
potential risks and develop an effective
response to device malfunction. The
objective of this study was to determine
the physical parameters required to
rupture balloon devices and to develop a
protocol to efficiently re-establish a patent
airway.
A model of subglottic stenosis was
designed to determine deflation time
required to withdraw a balloon (Figure 1).
Dilation balloons (15-16.5-18 mm
Hercules 3 stage, Cook Medical) were
inflated to predetermined pressure and
20N axial tension pulled against balloon
to simulate force applied by surgeon.
Balloons were punctured with 23G needle
through a flexible endoscope. Deflation
time, defined as the time required for fluid
egress until tension force decreased from
20N to 10N, and number of puncture
attempts were recorded. Decreased
tension allowed for balloon removal.
E. Brandon Strong, Daniel J. Cates,
Derrick R. Randall, Peter C. Belafsky
University of California at Davis
Department of Otolaryngology-Head and Neck Surgery
Center for Voice and Swallowing
2521 Stockton Boulevard, Suite 7200, Sacramento, CA 95817 USA
Increasing the inflation pressure of a malfunctioning dilator and
placing the patient in a horizontal position may promote safe
balloon removal. Spontaneous rupture occurred at 12 atm
inflation, and consistent rupture with needle puncture occurred
at 8 atm inflation. Partially decompressed balloons can take
between 0 and 87.5 seconds to deflate, which may be much
longer than many practitioners would expect. In the rare event
that a malfunction does occur, having an established protocol
may reduce the chances of a serious complication.
Figure 3. Flowchart of Proposed Emergency Protocol.
E. Brandon Strong
University of California, Davis
Figure 2. Mean Number of Puncture Attempts to breach balloon
integrity (n=23).
Inflation Pressure, atm (n)
Median Deflation Time, seconds (Range)
2 (n=7) 30.2 (7.1-87.5)
4 (n=8) 21.75 (8.6-79.4)
6 (n=8) 17.5 (0-55.3)
8 (n=4) 0
12 (n=4)* 0
Figure 1. Model of Subglottic Stenosis. A) Diagram B) Photograph
Table 1. Median Deflation Times after Needle
Puncture.
*spontaneous rupture without puncture
