Use of a carbonated beverage to disintegrate a phytobezoar
obstructing the intrathoracic portion of the oesophagus of a horse
L. C. Livesey*
, E. Yorke
, A. Parra
, Q. Gray
, C. Davies
, D. Weldon
, J. Schumacher
, C. Howard
, T. Sierra-Rodriguez
and M. Mora-Pereira
Tuskegee University College of Veterinary Medicine, Auburn, Alabama;
Southeast Equine Veterinary Services,
Phenix City, Alabama;
J.T. Vaughan Large Animal Teaching Hospital, Auburn University College of Veterinary
Medicine, Auburn, Alabama; and
Bluegrass Animal Clinic, Grayson, Kentucky, USA
*Corresponding author email: firstname.lastname@example.org
Keywords: horse; phytobezoar; carbonated beverage; oesophageal obstruction; disintegration
This report describes the treatment of a 17-year-old American
Quarter Horse gelding for an oesophageal obstruction of
approximately 24 h’duration. An intraluminal oesophageal
mass resembling a phytobezoar and located close to the
cardia, was observed during endoscopic examination of the
oesophagus of a horse showing signs of oesophageal
obstruction. An intrathoracic oesophageal diverticulum, ﬁlled
with ﬂuid, was observed about 40 cm proximal to the
obstruction. The end of a nasogastric tube was guided
beyond the diverticulum, using gastroscopic observation, so
that its tip rested close to the obstruction. The obstruction
failed to disintegrate or move into the stomach despite
vigorous, prolonged lavage. With the nasogastric tube left in
place, and the horse’s head elevated, 0.5 L cola was
administered adjacent to the obstruction through the
nasogastric tube. The head was maintained in the elevated
position for an hour, after which time the head was lowered
and oesophageal lavage resumed. The nasogastric tube was
passed into the stomach within 3 min of re-instituting lavage.
The successful use of a carbonated beverage to treat human
patients for oesophageal or gastrointestinal obstruction
caused by a phytobezoar is well documented. Carbonated
beverages have also been reported to be effective in
treating horses for gastric and enteric impactions caused by
persimmon seeds. Administering cola into the oesophagus
may help resolve oesophageal obstruction of horses caused
by a phytobezoar or impacted feed material when horses are
refractory to other treatments.
A bezoar is a mass of ingested, undigested material within the
alimentary tract that is resistant to disintegration (Chun and
Popachin 2017). Phytobezoars are concretions formed in the
gastrointestinal tract and are composed chieﬂy of undigested
compacted vegetable ﬁbre. Diospyrobezoars are a type of
phytobezoar composed of persimmon seeds. Diospyrobezoars
are typically harder than other bezoars, because persimmon
seeds have a high concentration of tannins, which, in the
presence of hydrochloric acid in the stomach, form a glue-like
coagulum (Chun and Popachin 2017). Although impacted
feed material is a common cause of intraluminal oesophageal
obstruction in the horse (Hillyer 1995; Feige et al. 2000;
Chiavaccini and Hassel 2010), the presence of a concretion of
plant material (phytobezoar) is unusual.
Cola is commonly used in human patients to disintegrate
gastric and intestinal phytobezoars and diospyrobezoars
(Chung et al. 2006; Ladas et al. 2013; Iwamuro et al. 2015) and
is also widely used to resolve oesophageal obstruction caused
by any food bolus (Karanjia and Rees 1993; Cotton 1993; Ko
and Enns 2008; Ki Hoon et al. 2010; Leopard et al. 2011;
Shaﬁque et al. 2013). Disimpaction rates of oesophageal
obstructions using carbonated beverages, or other gas forming
agents, alone have been reported in people ranging from 65%
(Zimmers et al. 1988) to 100% (Rice et al. 1983; Mohammed
and Hegedus 1986; Karanjia and Rees 1993). Gastric
phytobezoar resolution using carbonated beverages was
achieved in 91.3% of cases in human patients, either as a single
treatment, or combined with further endoscopic techniques
(Ladas et al. 2013). Cola has been administered successfully to
horses to breakup gastric diospyrobezoars (Rodriguez-Hurtado
et al. 2007; Banse et al. 2011) and enteric phytobezoars/
diospyrobezoars (Banse et al. 2011). The following report is, to
our knowledge, the ﬁrst to describe the use of cola to
disintegrate an oesophageal obstruction in a horse.
A 17-year-old, 418 kg American Quarter Horse gelding was
presented to the Tuskegee University College of Veterinary
Medicine because of signs of intraluminal oesophageal
obstruction ﬁrst observed 20 h earlier. The diet consisted of free
choice coastal bermuda hay, and 12% sweet feed twice daily.
The referring veterinarian reported that he was unable to pass
a nasogastric tube into the stomach. The horse had developed
an oesophageal obstruction 12 months previously, but on that
occasion the obstruction had resolved without treatment.
The horse was obtunded, and its heart rate was elevated (68
beats/min) was elevated. The horse’s rectal temperature
(36.9°C), respiratory rate (20 breaths/min) and lung sounds
were normal. Saliva ﬂowed intermittently from each nostril,
and the horse periodically coughed up saliva. The horse’s
PCV was 40%, and its TP was 7.0 g/dL.
Diagnosis and treatment
The horse was sedated with 2.5 mg of detomidine (0.006 mg/
kg bwt i.v.). Acepromazine (0.05 mg/kg bwt i.v.) and
propantheline bromide (0.07 mg/kg bwt i.v.) were administered
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1EQUINE VETERINARY EDUCATION
Equine vet. Educ. (2019) ()-
for their spasmolytic properties. Flunixin meglumine (1.1 mg/kg
bwt i.v.) was administered as an analgesic, and crystalline
ceftiofur (6.6 mg/kg bwt i.m.) was administered because of the
likelihood of aspiration pneumonia.
A nasogastric tube passed into the oesophagus to
perform oesophageal lavage retroﬂexed repeatedly soon
after entering the thoracic portion of the oesophagus. During
endoscopic examination of the oesophagus, a smooth-
surfaced green/brown concretion was seen after passing the
endoscope to 140 cm from the nares (Fig 1). The obstruction
completely occluded the oesophageal lumen and did not
move when gently pushed with the endoscope. As the
endoscope was retracted, a ﬂuid-ﬁlled diverticulum was
identiﬁed 40 cm cranial to the obstruction, on the ventral
aspect of the oesophagus (Fig 2). A mucosal stricture was
seen at the distal limit of the diverticulum.
Twenty litres of a balanced electrolyte solution
supplemented with 500 mL 23% calcium gluconate and
160 mEq potassium chloride were administered through an
indwelling intravenous catheter to correct dehydration and
presumed electrolyte abnormalities resulting from the
longstanding duration of the intraluminal oesophageal
obstruction. Detomidine (0.01 5 mg/kg bwt i.v.) and
propantheline bromide (0.07 mg/kg bwt i.v.) were administered
for their spasmolytic properties at 3-h intervals while the horse
received ﬂuid therapy.
We observed that the obstruction of the oesophagus
persisted during endoscopic examination of the oesophagus,
performed after administering the ﬂuids and spasmolytic
drugs. The oesophagus was lavaged intermittently during the
subsequent 6 h, with the horse sedated using detomidine
(0.01 mg/kg bwt i.v.) to ensure that its head remained
lowered throughout the procedure. Lavage episodes were
prolonged, and large volumes of water were used. To ensure
the tube was placed accurately for effective lavage and to
prevent it from becoming placed inadvertently into the
diverticulum, a gastroscope inserted into the oesophagus
adjacent to the nasogastric tube was used to guide the
nasogastric tube to a position immediately proximal to the
phytobezoar (Fig 1).
Lidocaine HCl (2%) was applied to the oesophageal
mucosa, through the biopsy channel of the endoscope, to
relieve the oesophageal spasm, but despite this and
previously mentioned treatments, the appearance and
position of the obstruction remained unchanged.
One-half litre of cola was administered over a period of
3 min to the site of obstruction through the nasogastric tube,
using a funnel, with the horse’s head elevated and supported
by a dental stand. Detomidine HCl (0.005–0.01 mg/kg bwt
i.v.) was administered to the horse periodically, to keep it
from moving. The oesophagus was again lavaged with water
1 h after cola had been administered, after conﬁrming with
the gastroscope which was situated in the oesophagus
adjacent to the nasogastric tube, that the end of the
nasogastric tube remained situated just proximal to the
phytobezoar. By means of the endoscope, the obstruction
was observed to disintegrate approximately 180 s after
lavage using a small volume of water, allowing the end of
the nasogastric tube and gastroscope to be passed through
the cardia into the stomach. The oesophageal mucosa
at the site of the obstruction was observed to be ulcerated
circumferentially (Fig 3).
Handfuls of soaked alfalfa pellets and short grass were
offered to the horse for short periods, beginning 12 h after the
obstruction was resolved. The amount of feed offered initially
was small but was gradually increased. There were no further
episodes of oesophageal obstruction during 8 days of
hospitalisation. The horse was treated for aspiration
pneumonia with broad spectrum antimicrobial drugs and
The horse was re-examined 60 days after discharge
because of intermittent episodes of choke that began to
occur 3 days before the horse was represented to the
hospital. Endoscopic examination revealed the formation of
a mucosal stricture at the site of the obstruction, close to the
cardiac sphincter (Fig 4). The diverticulum, although ﬁlled
with feed, was detectable during examination of a contrast
oesophagram (Fig 5). Three months after discharge, the horse
Fig 1: Endoscopic view of the phytobezoar lodged immediately
cranial to the cardiac sphincter. Correct placement of
nasogastric tube (NGT) for irrigation conﬁrmed.
Fig 2: Endoscopic view of the intrathoracic oesophageal
diverticulum. The margins (blue arrows) of the diverticulum (D),
the distal oesophageal lumen (L) and the partial stricture (S) are
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2 Use of cola in intraluminal oesophageal obstruction
was subjected to euthanasia because of increased
frequency of oesophageal obstruction.
The most common equine oesophageal disease is simple
obstruction (i.e. choke) (Hillyer 1995; Feige et al. 2000), which
is usually a primary problem caused by the ingestion of
inadequately masticated dry, ﬁbrous material (e.g. hay) or
poorly soaked beet pulp (Hillyer 1995; Feige et al. 2000;
Chiavaccini and Hassel 2010). Oesophageal obstruction may
also be seen as a secondary feature of other structural or
functional oesophageal conditions, such as ulceration,
stricture, megaoesophagus, neoplasia, compression of the
oesophagus secondary to a space-occupying lesion,
presence of a diverticulum or an oesophageal cyst.
Secondary oesophageal obstruction should be suspected in
cases of recurrent “choke”and in those cases where the
affected horse responds poorly to treatment using spasmolytics
and oesophageal lavage (Hillyer 1995; Chiavaccini and Hassel
2010). Oesophageal phytobezoars of people are rare and
occur most commonly in patients with structural or functional
oesophageal abnormalities (Goel et al. 1995; Ki Hoon et al.
2010; Yaqub et al. 2012). The oesophageal diverticulum
observed in this case may have contributed to the formation
of the phytobezoar and may have reduced the efﬁcacy of
oesophageal lavage. We are aware of only three horses
reported to have suffered from choke caused by an
oesophageal phytobezoar (MacDonald et al. 1987; Ford
et al. 1991; Orsini et al. 1991). Two of these three horses had a
phytobezoar that was associated with an oesophageal
diverticulum, similar to this case (MacDonald et al. 1987; Ford
et al. 1991).
The horse was reported to have suffered from only one
mild episode of oesophageal obstruction prior to the
presenting problem. The difﬁculty in passing a nasogastric
tube was likely a consequence of the tube entering the
diverticulum and resulting in retroﬂexion of the tube. The mild
stricture observed adjacent to the distal border of the
opening of the diverticulum may have contributed to the
propensity for the tube to enter the diverticulum.
Administering cola to human patients to resolve gastric
phytobezoars is an effective, noninvasive treatment and is
often the only therapeutic agent administered. Cola is
sometimes administered in conjunction with endoscopically
assisted retrieval of the mass, or mixed with cellulase or
pancreatic enzymes (Mohammed and Hegedus 1986;
Karanjia and Rees 1993; Chung et al. 2006; Ko and Enns 2008;
Coskun et al. 2011; Ladas et al. 2013; Shaﬁque et al. 2013;
Chun and Popachin 2017). Administering cola rectally to
human patients to break down a fecolith has been reported
(Lee and Kim 2015; Ontanillo et al. 2017). Injecting the cola
directly into the phytobezoar through the endoscopic
accessory port of the endoscope, may accelerate
disintegration of the phytobezoar (Iwamuro et al. 2015). The
advantages of administering cola to cause disintegration of
a phytobezoar include the minimal mucosal damage caused
Fig 3: Endoscopic view of the oesophageal lumen after
dissolution of the phytobezoar. There is circumferential pressure
necrosis of the oesophageal mucosa at the site of the
obstruction, immediately cranial to the cardiac sphincter.
Fig 4: Endoscopic view of oesophageal stricture formation at the
site of the obstruction, 60 days after presentation.
Fig 5: Contrast oesophagram showing diverticulum (blue arrows)
and associated partial stricture (red arrow) at the level of the
heart base, 60 days after presentation.
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L. C. Livesey et al. 3
by this intervention. In many cases, the obstruction
(oesophageal, gastric or intestinal) is relieved solely by
administering the cola, thus eliminating the likelihood of
damaging the oesophageal mucosa or perforating the
oesophagus, complications that may accompany attempts
to remove the obstruction by endoscopic manipulation or by
lavage (Shaﬁque et al. 2013). Administering cola may
eliminate the need for surgical removal of a phytobezoar
(Ladas et al. 2002). The successful treatment of equids for a
gastric diospyrobezoars (Rodriguez-Hurtado et al. 2007; Banse
et al. 2011) and enteric phytobezoars or diospyrobezoars
(Banse et al. 2011) using cola has been previously described.
To our knowledge, using cola to break down an
oesophageal obstruction in horses has not been described
prior to this case report.
Although the mechanism of action of cola has not been
fully elucidated, investigators have speculated that the
mucolytic action of sodium bicarbonate and the acidifying
action of carbonic and phosphoric acid disintegrate the
bezoar. Carbon dioxide bubbles penetrating the microscopic
pores on the surface bezoar may also assist disintegration of
the phytobezoar (Iwamuro et al. 2015). Sugar-free cola has
been reported to be successful in treatment of people with
phytobezoars (Ertugrul et al. 2012; Kramer and Popachin 2012;
Iwamuro et al. 2015), suggesting the mechanism of action is
unrelated to sugar content. Use of sugar-free formulations of
cola may be preferable if larger volumes are administered,
particularly in equids suspected of having insulin dysregulation
resulting from equine metabolic syndrome and/or pituitary
pars intermedia dysfunction.
Using cola in this case appeared to be instrumental in
disintegrating the oesophageal obstruction that had not
resolved with other forms of therapy. More aggressive
interventions have been described, including lavage using a
cuffed endotracheal tube (e.g. the Rusch oesophageal ﬂush
probe, MEDVET, Kernen, Germany) passed intranasally into the
oesophagus (Orsini and Divers 2014). These interventions may
be attempted with the horse sedated or anaesthetised, but the
risk of oesophageal injury is increased and such injury may
result in formation of a stricture, or even perforation of the
oesophagus (Orsini and Divers 2014). If these attempts to
remove the obstruction are unsuccessful, intraluminal
obstructions in the cervical portion of the oesophagus can be
resolved by performing an oesophagotomy. Surgical treatment
should be considered a last resort, because complications
associated with oesophagotomy are common (Craig et al.
1989; Koenig et al. 2016) and include surgical site infections,
wound dehiscence and stricture formation. The surgical
approach to the intrathoracic oesophagus is complicated
(Ford et al. 1991), and likely to result in post-operative
complications (J. Schumacher, personal communication).
We suggest that administering cola to the site of
obstruction through a nasogastric tube, or through the
accessory port of an endoscope, may be helpful in
disintegrating intraluminal oesophageal obstructions. The
dramatic response shown by this horse to administration of
cola, coupled with the high incidence of success of this simple
treatment in human patients, indicates that administering a
cola to the site of an oesophageal impaction may reduce the
duration and volume of corrective oesophageal lavage, thus
potentially reducing the incidence of oesophageal trauma
and aspiration pneumonia. We recommend that the cola be
administered in a controlled manner, and that the head
remain elevated to allow time for the cola to be absorbed into
the intraluminal oesophageal obstruction. These precautions
should minimise the likelihood of cola aspiration.
Since submission of the original manuscript, four further cases
of intraluminal oesophageal obstruction that had not responded
to conventional treatment protocols were successfully resolved
using administration of a carbonated beverage, as described
in this report. Details of these cases are described in
Supplementary Item 1. We are very interested in assessing the
efﬁcacy of this treatment protocol in a larger population of
horses and have started to collect data from practitioners using
a short questionnaire (Supplementary Item 2).
Authors’declaration of interests
No conﬂicts of interest have been declared.
Ethical animal research
This was a client horse that was presented to our hospital and
treated appropriately. Extra cases described in the addendum
were client horses and treated appropriately.
The authors are very grateful to Dr Jim Schumacher for his
help in editing the manuscript.
L. Livesey, E. Yorke, J. Schumacher, C. Howard, S. Kimura,
T. Sierra Rodriguez and M. Mora Pereira contributed to case
management and preparation of the manuscript. Q. Gray
and C. Davies contributed to case management. All authors
gave their ﬁnal approval of the manuscript.
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Additional Supporting Information may be found in the online
version of this article at the publisher’s website:
Supplementary Item 1: Additional cases.
Supplementary Item 2: Questionnaire.
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L. C. Livesey et al. 5