Endobronchial Argon Plasma Coagulation
for Treatment of Hemoptysis and
Neoplastic Airway Obstruction*
Rodolfo C. Morice, MD, FCCP; Turhan Ece, MD; Ferah Ece, MD; and
Leendert Keus, RPFT
Study objective: To evaluate the usefulness of endobronchial argon plasma coagulation (APC) for
the treatment of hemoptysis and neoplastic airway obstruction.
Design: Retrospective study.
Setting: Bronchoscopy unit of a university hospital.
Patients: A total of 60 patients with bronchogenic carcinoma (n ⴝ 43), metastatic tumors affecting
the bronchi (n ⴝ 14), or benign bronchial disease (n ⴝ 3). Indications for intervention were
hemoptysis (n ⴝ 31), symptomatic airway obstruction (n ⴝ 14), and both obstruction and hemoptysis (n ⴝ 25). Hemoptysis was stratified as a volume of > 200 mL/d (n ⴝ 6), > 50 to 200 mL/d
(n ⴝ 23), or < 50 mL/d but persistence for > 1 week (n ⴝ 27). The mean (ⴞ SD) duration of
hemoptysis was 16.5 ⴞ 16.1 days before intervention. Obstruction sites were the trachea (n ⴝ 8),
mainstem bronchi (n ⴝ 21), and lobar bronchi (n ⴝ 30). In 24 cases, the patient had obstructions
at multiple sites. The mean size of the pretreatment obstruction was 76 ⴞ 24.9%.
Interventions: APC, a noncontact form of electrocoagulation, was performed via flexible bronchoscopy. Sixty patients underwent 70 procedures. Conscious sedation without endotracheal
intubation was used in all patients except four, who were mechanically ventilated because of
underlying respiratory failure.
Measurements and results: All patients with hemoptysis experienced a resolution of bleeding
immediately after APC. Hemoptysis from treated sites did not recur during a mean follow-up
duration of 97 ⴞ 91.9 days. Patients with endoluminal airway lesions had an overall decrease in
mean obstruction size to 18.4 ⴞ 22.1%. All patients with obstructive lesions, except one who died
of sepsis, experienced symptom improvement. In these patients, symptom control was maintained
during a median follow-up period of 53 days (range, 18 to 321 days). There were no complications
related to the procedure.
Conclusions: APC is effective for the treatment of endoluminal hemoptysis and airway obstruction. The procedure can be performed in an outpatient setting or at the bedside in the ICUs. APC
provides a simpler, lower-risk alternative to other interventional endobronchial techniques.
(CHEST 2001; 119:781–787)
Key words: airway obstruction; argon plasma coagulation; bronchial neoplasms; bronchoscopy; electrocoagulation;
endobronchial therapy; hemoptysis
Abbreviations: APC ⫽ argon plasma coagulation
airway invasion is common among
N eoplastic
patients with lung cancer and metastatic malignancies.1,2 These patients may present with symptoms caused by tracheobronchial tumor extension,
such as dyspnea, bleeding, intractable cough, and
postobstructive pneumonia. In selected cases, bronchoscopic interventions can prevent imminent death,
*From the Section of Interventional Pulmonary Medicine, Department of Pulmonary Medicine, The University of Texas M.D.
Anderson Cancer Center, Houston, TX.
Supported by the Mary L.E. McConnell Fund for Lung Research.
Manuscript received June 14, 2000; revision accepted October
11, 2000.
offer clinical stability that will allow additional cancer
treatment, or palliate symptoms.3 Endobronchial
therapies can also be curative in some patients with
early-stage malignancies4 or benign airway disease.5
Technical developments in the past 20 years have
generated multiple types of bronchoscopic treatments.6 –9 A significant portion of these techniques,
however, have been out of the reach of most clinical
bronchoscopists. High equipment costs, scarcities of
Correspondence to: Rodolfo C. Morice, MD, FCCP, Section of
Interventional Pulmonary Medicine, The University of Texas
M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 76,
Houston, TX 77030; e-mail: [email protected]
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781
training resources, cumbersome instrumentation,
and operational safety concerns have prevented a
more general utilization of these technologic advances.
Argon plasma coagulation (APC) is a form of
noncontact electrocoagulation. It offers the simplicity and low cost of an electrocoagulator with the
noncontact approach of an Nd-YAG laser. The noncontact feature of APC allows rapid coagulation with
minimal manipulation of and mechanical trauma to
the target tissue. The term plasma is used to describe
an electrically conducting medium produced when
the atoms in a gas become ionized. It is sometimes
referred to as the fourth state of matter, distinct from
the solid, liquid, and gaseous states. APC utilizes
electrically conductive argon plasma as a medium to
deliver high-frequency current via a flexible probe.
The argon plasma flow transfers electricity between
the probe and the target tissue (Fig 1). The basic
APC system is composed of an argon gas source, a
computer-controlled high-frequency electrosurgical
generator, and the endoscopic probe (Fig 2). Tracheobronchial access is obtained by passing the
probe through the working channel of the bronchoscope.
The usefulness of APC has been documented in
numerous studies of hemostasis and ablation of
lesions in GI endoscopy.10,11 Publications in the field
of otolaryngology have reported the effectiveness of
APC for the treatment of epistaxis12 and upper
airway papillomatosis.13 We studied the effectiveness
of APC in therapeutic bronchoscopy for patients
with hemoptysis and/or symptomatic endoluminal
airway obstruction. We also studied the feasibility of
Figure 1. Schematic representation of a section of the APC
probe and electrically conductive gas (argon plasma) interacting
with the target tissue. The electrode within the APC probe
ionizes the argon gas, allowing noncontact flow of electrical
current between the probe and the tissue. The argon plasma
beam acts not only in a straight line, along the axis of the probe,
but also laterally, as shown in this diagram. On arrival to the
tissue, the application of energy causes uniform zones of desiccation (A), coagulation (B), and devitalization (C) in the areas
receiving treatment.
Figure 2. Photographic depiction of the APC equipment
(ERBE USA Inc). The upper component is an electrosurgical
unit (ERBOTOM ICC 200) that generates the high-frequency
voltage required to power the APC unit located immediately
below (APC 300). The electrosurgical unit can be used independently of the APC, allowing the option of using standard electrocautery snares and probes in combination with APC.
using this technique through the flexible bronchoscope in the bronchoscopy suite or as a bedside
procedure in ICUs.
Materials and Methods
For this study, endobronchial therapy with APC was indicated
for patients with hemoptysis or symptomatic endoluminal airway
obstruction. Patients with hemoptysis were eligible for this study
if they met all of the following criteria: (1) bleeding originated
within the tracheobronchial tree; (2) the site of bleeding was
identifiable during flexible bronchoscopy; and (3) there was an
absence of coagulopathy or other medically correctable causes of
hemoptysis. Patients with obstructing airway neoplasms were
included in this study if they met all of the following criteria: (1)
symptoms were related primarily to airway obstruction and not to
systemic disease; (2) the tumor was located within the lumen of
the airway; (3) the margins between tumor and normal airway
were identifiable; (4) tumor length was ⱕ 3.5 cm; and (5) there
was functional lung distal to the obstruction or relief of postobstructive pneumonia was feasible.
All endobronchial APC procedures were performed with a
flexible bronchoscope. Except in those patients who required
mechanical ventilation because of respiratory failure owing to
their underlying disease, all procedures were performed transnasally or transorally in the bronchoscopy suite. Local anesthesia
and conscious sedation with IV midazolam and fentanyl were
administered before and during the procedure. Oxygen was
supplemented via nasal prongs. Pulse oximetry saturation, BP,
and pulse were monitored during bronchoscopy. Patients who
were receiving mechanical ventilation in the ICUs underwent
endobronchial APC procedures at bedside through an oral-tracheal
tube. These patients were already receiving continuous sedation
with IV propofol and/or midazolam as part of critical-care sedation
protocols for patients receiving mechanical ventilation.
Endobronchial APC was performed with an argon plasma
coagulator unit (APC 300 and ERBOTOM ICC 200; ERBE USA
Inc; Marietta, GA) via a flexible bronchoscope (model BF-1T10;
Olympus America Inc; Melville, NY). Energy at 30 to 40 W and
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Clinical Investigations
argon flow at 1.6 L/min were applied through a 2.3-mm diameter,
220-cm length APC monopolar probe. The probe was inserted
through the working channel of the bronchoscope. The target
tissue was endoscopically visualized and then coagulated, and the
devitalized tissue was mechanically removed with grasping forceps. Patients who had incomplete lesion debulking after one
treatment or who developed evidence of endobronchial mucus
plugging underwent a second bronchoscopic procedure for removal of devitalized tissue after 48 to 72 h. Additional endobronchial APC treatments were performed on patients who met study
entry criteria if they developed recurrent or new airway disease.
Patients who had residual or additional disease not amenable to
further APC interventions were considered for other forms of
local or systemic therapy. Patients who had APC treatments for
benign lesions were followed up with surveillance bronchoscopy
3 months after therapy and as clinically indicated.
Patients’ demographic characteristics, underlying diagnoses,
severity and duration of hemoptysis and/or dyspnea, and clinical
or roentgenographic manifestations of obstruction or infection
were recorded. The location of the airway lesions, the degree of
obstruction, the immediate response to therapy, and any complications were documented at the completion of the endobronchial
therapy session. The percentage of airway obstruction was estimated by visual comparison between the area of stenosis and the
healthy proximal airway. Improvement of dyspnea after APC
therapy was classified as excellent if, based on patients’ estimations, the dyspnea resolved or was at least reversed to the level of
the dyspnea present before the onset of the airway obstruction.
Improvement was classified as moderate if the dyspnea improved
without complete resolution and the improvement was less than
it existed before the onset of airway obstruction. After bronchoscopic interventions, patients’ outcomes were monitored at 24 h
and thereafter as clinically indicated (median, 22 days; range, 5 to
67 days).
Results
From November 1998 to April 2000, 60 patients
underwent 70 endobronchial APC treatments. Patients’ demographic characteristics, diagnoses, and
locations of endoluminal airway lesions are shown in
Table 1.
Conscious sedation without endotracheal intubation was used in all patients except four, who were
receiving mechanical ventilation in the ICUs because of respiratory failure caused by their underlying disease. The first author performed all the
bronchoscopic interventions. Fifty-seven treatments
(81%) were conducted on ambulatory patients.
These patients were discharged home on the day of
the procedure after remaining in stable condition
during a period of observation in the bronchoscopy
recovery area. In the remaining 13 cases, the patients
were hospitalized because of their primary clinical
conditions. No patient was hospitalized because of
the bronchoscopic intervention.
Indications for APC therapy were hemoptysis (31
patients), symptomatic endoluminal airway obstruction (14 patients), and both obstruction and hemoptysis (25 patients) (Table 2). The onset of hemoptysis
occurred at a mean (⫾ SD) of 16.5 ⫾ 16.1 days
Table 1—Characteristics of Patients, Diagnoses, and
Location of Airway Lesions*
Characteristics
Values
Sex
Male
Female
Median age, yr
Diagnoses
Lung cancer
Non-small cell
Small cell
Metastatic
Renal
Thyroid
Melanoma
Benign
Telangiectasia
Bronchiectasis
Fibrous web
Median time from diagnosis
to APC treatment, mo
Location of airway lesions†
Trachea
Main brochi
Right mainstem
Left mainstem
Lobar bronchi
Right upper lobe
Bronchus intermedius
Right middle lobe
Right lower lobe
Left upper lobe
Left lower lobe
43
17
63 (range, 29–84)
42
1
12
1
1
1
1
1
7.3 (range, 0–62)
10
20
23
17
9
2
2
18
16
*Values are presented as No. of patients.
†Thirty-eight patients had airway lesions at more than one location.
Values include all sites of endoluminal airway obstruction and/or
bleeding.
before endobronchial intervention. Bleeding was
severe (⬎ 200 mL/d) in 6 patients, moderate (⬎ 50
to 200 mL/d) in 23 patients, and mild (ⱕ 50 mL/d)
but persistent for ⬎ 1 week in 27 patients (mean
onset, 19.3 ⫾ 14.1 days). Endoluminal airway bleeding was completely controlled in all patients immediately after APC. No recurrence of hemoptysis from
a treated site was noted during a mean follow-up
period of 97 ⫾ 91.9 days. Three patients were
treated with APC for a second episode of hemoptysis
that originated from a new endobronchial site at 53,
87, and 101 days after the initial treatment. One
patient required arterial embolization after APC for
management of bleeding that originated from a
peripheral lung mass beyond the reach of the bronchoscope. Except for two patients who had benign
conditions, all patients with hemoptysis had malignant diseases. Bleeding from benign lesions occurred in areas of dilated vascular proliferation
and bronchiectasis associated with prior externalbeam irradiation.
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783
Table 2—Indications for APC Therapy and Patients’
Manifestations of Endoluminal Airways Disease*
Variables
Indications
Hemoptysis
Hemoptysis and obstruction
Obstruction
Clinical manifestations
Dyspnea
Severe
Moderate
Mild
Hemoptysis
⬎ 20 mL/24 h
⬎ 50–200 mL/24 h
⬍ 50 mL/24 h
Pneumonia
Cough
Severe
Moderate
Mild
Values
31
25
14
9
42
19
6
23
27
5
18
43
9
*Values are presented as No. of patients.
In the group of patients who had symptomatic
obstruction, the endoluminal airway lesions were
located in the trachea in 8 cases, in the mainstem
bronchi in 21 cases, and in the lobar bronchi in 30
cases. In 24 of these cases, the patient had an
obstruction at more than one site. Except for one
patient who had a symptomatic bronchial web-like
stenosis, all patients with bronchial obstruction had
malignant disease. Patients with endoluminal masses
had a pretreatment reduction of the healthy airway
lumen that averaged 76 ⫾ 24.9%. Immediately after
APC and mechanical debulking, the obstruction
decreased an average of 26 ⫾ 30.5%. Seven patients
required an additional bronchoscopic procedure for
the removal of devitalized tissue 48 to 72 h after the
initial APC treatment. This second intervention further decreased the overall posttreatment bronchial
obstruction to a mean value of 18.4 ⫾ 22.1% (Fig 3).
There were no complications directly related to
endobronchial therapy.
Symptoms improved immediately after tumor destruction in all patients except for one, a patient who
was receiving mechanical ventilation who died within
48 h owing to neutropenic sepsis and underlying
pneumonia. Improvement of dyspnea immediately
after endobronchial tumor debulking was excellent
in 37 cases (53%) and moderate in 32 cases (46%)
(Fig 4). Two patients underwent a second APC
intervention for mechanical debulking of recurrent
endoluminal obstruction 149 and 210 days after the
initial treatment. Twenty-one patients also received
high-dose-rate endobronchial brachytherapy after
APC for a boosting effect or ablation of the residual
tumor. Relief of dyspnea related to obstruction was
maintained for a median follow-up period of 53 days
(range, 18 to 321 days).
Discussion
APC has been used for ⬎ 10 years in open surgery,14 laparoscopy,15 and GI endoscopy.16 This is
the first study (to our knowledge) that reports on the
feasibility and effectiveness of APC for hemostasis
and debulking of endoluminal tracheobronchial lesions through the flexible bronchoscope. The excellent safety profile, readiness of use, and relatively low
Figure 3. Diagram indicating the degree of endoluminal obstruction before treatment (left, A) and
after treatment (right, B). Values are presented as the mean percent reduction of the healthy airway
lumen. The numbers correspond to 1 SD of the mean values.
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Clinical Investigations
Figure 4. An example of tumor debulking using APC for the treatment of an airway obstruction in a
patient with non-small cell carcinoma. Top left, A: a pretreatment endoscopic examination shows an
80% occlusion of the distal trachea by an endoluminal mass. This tumor originated in the right upper
lobe and extended through the right mainstem bronchus into the trachea. Top right, B: a pretreatment
flow-volume loop tracing that is indicative of a severe, fixed central airway obstruction. Bottom left, C:
a complete reopening of the trachea and right mainstem bronchus immediately after APC and tumor
removal. Bottom right, D: normalization of the flow-volume loop tracing 48 h after bronchoscopic
intervention.
cost make APC most suitable for therapeutic applications through the flexible bronchoscope in the
outpatient setting. This study also attests to the
operational simplicity and portability of equipment
that allows expansion of the range of therapeutic
interventions to bedside use in the ICUs. The noncontact approach offers advantages over other forms
of electrocoagulation. Avoiding tissue contact and
probe adhesion to friable tissues decreases the risk of
bleeding. It also allows the bronchoscopist to treat a
larger area very quickly.
Proper patient selection for therapy with endobronchial APC is crucial. For patients with hemoptysis, the bleeding source must be endobronchial and
within the reach of the bronchoscope for APC to be
effective. Patients with severe bleeding and respiratory compromise should be stabilized before any
intervention. Endobronchial therapy in these patients is aimed at preventing recurrence once the
acute episode of massive hemoptysis has decreased
or subsided. The selection of rigid vs flexible bronchoscopy to assess or treat massive hemoptysis most
likely reflects the user’s experience and the clinical
circumstances. The rigid bronchoscope allows better
suctioning and airway control, while the flexible
bronchoscope permits easier access and visualization
of distal airways.17 Flexible bronchoscopy was used
in all patients enrolled in this study.
The ablation of obstructive airway lesions should
be done with the purpose of regaining significant
lung function or relieving postobstructive pneumonia. In the absence of postobstructive pneumonia, no
benefit from endobronchial therapy will be gained if
the lung distal to the obstruction is nonfunctional, for
example in patients with extensive parenchymal tumor invasion or postradiation fibrosis. Patients selected for endobronchial APC should have primarily
respiratory rather than systemic symptoms of widespread malignancy. Airway lesions that are most
suitable for treatment with APC are those measuring
ⱕ 3.5 cm in length. To obtain the best results, these
tumors should protrude within the lumen and not
extend beyond the cartilage of the airway. Ideally,
the bronchoscopist would be able to identify the
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785
anatomic boundaries of the tumor and appreciate
that the airway not involved by tumor is wellpreserved. Patients who present with diffuse, concentric malignant infiltration and with significant
distortion of anatomic landmarks are best treated
with endobronchial brachytherapy.18 Furthermore,
obstructions caused by lesions that extrinsically compress the airway are best palliated with externalbeam radiation therapy or endoluminal stents.19
Some patients may require a combination of endobronchial therapies. APC can be used to control
bleeding before brachytherapy or to reestablish the
adequate opening of an occluded airway for subsequent passage of a catheter for brachytherapy. The
electroconductive properties of APC make this technique best suited for the removal of a tumor that may
have grown over stents without damage to the stent.
The latter use has been reported for APC applications in GI endoscopy.20 Our study also documented
the usefulness of APC therapy for hemostasis of
bleeding associated with benign vascular proliferation in central bronchiectasis and for the ablation of
an endoluminal web.
APC devitalizes tissue gradually by producing
temperatures that coagulate and desiccate tissue. As
the target surface becomes less electrically conductive, APC will automatically seek adjacent tissue with
less electrical resistance. This results in a homogenous but limited depth of penetration (approximately 3 mm). Thus, APC offers uniform coagulation and
good protection against airway perforation. When
debulking tumors with the APC, the visible surface
of the mass is sprayed with the argon beam. This
decreases the risk of bleeding and causes a variable
degree of tumor shrinkage by dehydration. The
tumor is removed through sequential cauterization
followed by peeling of tissue as it becomes crusted or
coagulated. Tissue is removed with a grasping forceps or suction. The extraction of devitalized tissue
in large pieces is desirable to shorten the duration of
the procedure. Pieces that do not fit through the
working channel of the bronchoscope are removed
by simultaneously withdrawing the bronchoscope
with the tissue attached to the biopsy forceps.
Although the APC is a noncontact method, the
bronchoscopist must hold the tip of the probe close
to the target tissue, usually within 3 to 5 mm.
Because the current follows the path of least resistance, holding the tip of the probe in proximity to the
side of the bronchial wall or the lesion will allow
current to flow laterally rather than on a straight
path. To prevent trauma to friable tissues, the tip of
the probe should be extended past the end of the
working channel of the bronchoscope only after the
target tissue has been properly identified. During
procedures performed with the patient under con-
scious sedation, the bronchoscopist also should anticipate unexpected movement of the target tissue
because of the patient’s cough. Use of the APC with
a therapeutic channel bronchoscope is recommended to facilitate the suction of secretions, blood,
and smoke.
The Nd-YAG laser is another noncontact thermal
device. It differs from APC in that it can generate
higher temperatures capable of tissue vaporization
and deeper penetration. In combination with rigid
bronchoscopy under general anesthesia, the NdYAG laser has been the method used most often for
the rapid removal of large tumors.21 Although it
offers less penetration, the argon plasma beam has
the advantage of not having to follow a straight path
like the Nd-YAG laser. Because APC seeks electroconductive areas, it can more easily access targets
located laterally, radially, or around anatomic corners. APC also does not generate a direct thermal
reaction with airway devices that do not conduct
electricity. Thus, the risks of igniting endotracheal
tubes or other airway catheters are much lower with
APC than with the Nd-YAG laser.22 Similarly, the
known risk of Nd-YAG laser-induced retinal injury to
the operator and technical personnel 23 does not exist
during APC instrumentation.
Despite the safety features of APC, care must be
taken to reduce risks inherent to any thermal device.
The APC probe should extend 0.5 to 1.0 cm beyond
the tip of the bronchoscope to avoid collateral
thermal damage to the bronchoscope. Supplemental
oxygen should be kept at the minimum safe level. In
general, maintaining inspired concentration of supplemental oxygen at ⱕ 40%, or intermittently reducing it to this level, is recommended during APC
application. No fires or technical complications occurred during the interventions reported in this
study. There have been isolated case reports of
intestinal wall emphysema and pneumoperitoneum
after APC in GI endoscopy.24 Systemic air embolisms have also been reported during bronchoscopic
Nd-YAG laser interventions.25 In our patients, we
did not observe gas exchange impairment, bronchopulmonary barotrauma, or clinical manifestations of
gas embolism associated with the introduction of
low-flow, inert argon gas into the airway.
Patient selection for endobronchial tumor ablation
with APC requires the understanding that the mere
presence of endobronchial disease does not in itself
constitute an indication for endobronchial therapy.
Standard surgical, medical, and radiation treatments
remain the primary therapeutic modalities for patients with bronchopulmonary malignancies. Interventional bronchoscopy must be contemplated in the
context of multidisciplinary management of these
patients. Procedures such as APC that can be per-
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Clinical Investigations
formed in an outpatient setting or at the bedside in
the ICUs augment the therapeutic options available
to the clinical bronchoscopist. These techniques help
to transform the traditional role of the pulmonologist
from diagnostic bronchoscopist to active participant
in cancer therapy within multidisciplinary programs.
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