Cost analysis of Intubation-Related Tracheal Injury using a national
Nasir I. Bhatti, M.D.*1
Atta Mohyuddin, M.D. 1
Nancy Reaven. M.A.2
Susan E. Funk, M.B.A.2
Kulsoom Laeeq, M.D. 1
Vinciya Pandian, M.S.N, C.R.N.P. 1
Marek Mirski, M.D. 3
David Feller-Kopman, M.D.4
1 Dept. of Otolaryngology-Head & Neck Surgery, Johns Hopkins Hospital, Baltimore, MD
2 Strategic Health Resources, La Canada, CA
3 Dept. of Anesthesiology & Critical Care Medicine, Johns Hopkins Hospital, Baltimore, MD
4 Interventional Pulmonology, Johns Hopkins Hospital, Baltimore, MD
*Address for correspondence
Suite 6241, 601 North Caroline Street
Baltimore, MD 21287-0910
Presented at the Academy meeting of Otolaryngology Head and Neck Surgery, San Diego, CA,
October 4-7, 2009
Our objectives were to perform risk analysis of tracheal injuries caused by endotracheal
intubation (ETI) and to estimate the financial impact of these sequelae in adults.
We searched Medline, Cochrane, International Society for Pharmacoeconomics and Outcomes
Research, and Royal Society of Medicine databases for studies mentioning ETI and tracheal
We identified clinical manifestations and treatments and codified them into ICD-9 diagnosis and
procedure codes, intentionally excluding tracheostomies and other alternate etiologies of tracheal
injury. Using the Agency for Healthcare Research and Quality’s 2006 National Inpatient Sample,
we then compared patients with tracheal injury coded during the medical or surgical stay for
length of stay (LOS) and mean hospital cost with DRG (Diagnosis Related Group)-matched
controls; we also examined readmissions treating tracheal injury.
Tracheal injury presents as tracheal stenosis, tracheomalacia, tracheoesophageal fistula,
laryngotracheal ulceration, and vocal cord paralysis. A total of 3232 discharge records met
criteria for tracheal injury from ETI within the index hospital stay. Average LOS for patients
with tracheal injury (6.3 days; 95% Confidence Interval ((CI)): 6.0 – 6.3) exceeded LOS in the
uncomplicated sample (5.2 days; CI: 5.1 – 5.3) by 1.1 days. The average hospital cost was
$1,888 higher with tracheal injury ($10,375 (CI: $9,762-$10,988) vs. $8,487 (CI: $8,266 -
$8,669). LOS for procedures treating prior tracheal injury averaged 4.7 days and cost an average
of $11,025 per discharge.
Tracheal injury from endotracheal intubation is associated with a significant increase in health-
care costs that accrue both during the index admission and, even more importantly, during
subsequent hospitalizations required to treat the injury.
Endotracheal intubation (ETI) is a common procedure carried out in both emergent and non-
emergent clinical scenarios. Although necessary in many circumstances, the placement of an
endotracheal tube can be a source of morbidity and mortality. The incidence of airway injury
following ETI is estimated to occur with a frequency of 1-11% and can occur anywhere from the
teeth / lips to the distal trachea.1 Even with short-term intubation, injury to the posterior
commissure and subglottis is quite common.2 Whited prospectively studied 200 patients and
reported an incidence of tracheal stenosis of 4% for intubations lasting 5-10 days and up to 12%
for intubations lasting 11-24 days.3
The local risk factors associated with tracheal injuries following ETI include anatomic features
of the upper airway, trauma, number of intubation attempts, the size and mobility of the
endotracheal tube (ETT), the presence of a balloon cuff, and the duration of ETI. Of these
factors, the duration of ETI was the most important factor for developing post tracheal injuries.4,5
Airway injuries can present acutely either at the time of intubation, while the ETT is in place, or
some time after the intubation. Although some of these injuries are minor and self-limited, others
require treatment, which may occur either during the associated hospitalization or sometime
thereafter. The cost of treatment for ETI-associated tracheal injury has not previously been
The purpose of this study was, first, to identify post-intubation tracheal injury and its associated
impact on length of stay and cost to the index hospital admission and, second, to examine costs
related to subsequent readmissions required to treat the injury.
We performed a search of the clinical and health economics literature investigating the incidence
of complications, treatment approaches, and medical resource utilization associated with
complications including tracheal stenosis, tracheomalacia, tracheal perforation, and
tracheoesophageal fistula. We searched four large databases: Medline, Cochrane, International
Society for Pharmacoeconomics and Outcome Research (ISPOR), and the Royal Society of
Medicine. The literature of interest included descriptions and incidence rates of documented
complications associated with endotracheal tubes, treatment of complications, and cost and
information about the use of medical resources specific to the complications of interest or the
noted treatments. The literature search was performed iteratively, using basic keywords:
[endotracheal tube OR endotracheal intubation] AND [tracheomalacia OR tracheal stenosis OR
tracheal perforation OR tracheoesophageal fistula OR tracheal dilation OR tracheal injury].
We limited the search to English-language peer-reviewed studies published in the last 10 years
involving human subjects in order to define the relevant complications associated with ETI. In
preparation for the data analysis, we linked the narrative descriptions of complications and
treatments as documented in the literature to the most closely aligned ICD-9 (International
Classification Disease, Volume 9, diagnosis and procedural codes, World Health Organization.
See Tables 1&2).
Hospital Cost and Length of Stay
Data on hospital length of stay (LOS), charges, and costs were obtained from the 2006 National
Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), managed by the
Agency for Healthcare Research and Quality (AHRQ).6 AHRQ calculates LOS using the
discharge date minus admission date, thus allowing 0-day hospital inpatient stays. All costs,
charges, and LOS results reported in this document were developed using AHRQ’s discharge
weights to ensure that the results are as representative as possible. Hospital cost was estimated
from hospital charges using hospital-specific or group-average all payer inpatient cost-to-charge
ratios calculated by AHRQ. Thus, throughout this report, the “hospital cost” of discharges with
or without complications represents the full cost to the hospital itself of providing the services,
irrespective of how much reimbursement (if any) the hospital received.
Analysis of Tracheal Injury
Our analysis of patient-level data for tracheal injury was designed to yield data on two sets of
complication-related events: first, incremental costs and LOS associated with tracheal injury
identified during an index hospital admission for a non-tracheal reason; second, the costs of
subsequent hospital admissions required for repair of the tracheal injury occurring previously.
Injury Occurring During an Index Hospital Admission for Another Reason
Our approach was to identify a base population of admitted patients who experienced a tracheal
complication and to compare their hospital LOS and costs with a matched population of patients
undergoing similar medical or surgical admissions, but experiencing no tracheal injury. Inclusion
criteria were age ≥18 years and tracheal injury diagnosis code in any position other than primary
diagnosis in the hospital record. We used the tracheal injury diagnostic codes as shown in Table
1. We excluded patients with diagnosis and procedural codes that would act as confounders for
tracheal injury not related to endotracheal intubation. These include codes for neoplasms of the
larynx, trachea, and lung, codes for accidents and trauma to the airway, and codes denoting a
history of tracheostomy; likewise excluded were patients having a primary diagnosis of a
tracheal injury or having an implant procedure code and another procedure that might have
caused tracheal injury, such as a bronchoscopy with stenting, thermal ablation, or dilation.
Following the inclusion and exclusion criteria as shown in Table 3, we identified the Diagnosis
Related Group (DRG) associated with each admission and the number of patients meeting
inclusion/exclusion criteria in each DRG. Our analysis of cost and LOS for patients with tracheal
injury was based on a net population of 3232 patients in the 73 DRGs in which there was a
minimum of 10 patients for which we were able to document a tracheal injury with
complications. The minimum of 10 patients was instituted, in part, to comply with patient
privacy mandates covering federally maintained databases.
Matched Sample of Uncomplicated Discharges
For each DRG for which we were able to identify at least 10 patients with complications meeting
both our inclusion and exclusion criteria, we selected as the matched sample all in-patient
discharges for patients aged ≥18 years having the same DRG. For the matched population, we
applied the same exclusion criteria, and we also excluded patients with any diagnosis code
beginning with 99 (referring to ‘complications of care’). The resulting matched sample consisted
of 2,322,642 patients treated under the same DRGs as our ‘tracheal complications’ sample, but
absent any of the tracheal diagnoses, procedures, or complications examined in this study.
Tracheal Injury, Readmission
To establish the study population of patients requiring readmission for treatment of previously
occurring ETI-related tracheal injury, we queried the National Inpatient Sample (NIS) for
hospital admissions in which procedure codes specifying that a tracheal repair procedure (Table
2) was documented during an admission in conjunction with one of the diagnosis codes
specifying tracheal injury (Table 1). There were 263 discharge records meeting these basic
criteria. After excluding patients who had a tracheostomy procedure code; diagnosis codes
specific to complications of tracheostomy, history of tracheostomy, or attention to tracheostomy;
a mechanical ventilation code; or no cost data in the hospital record, a final population of 200
patients was available for this analysis.
Index-Admission Tracheal Injury
We were able to match hospital LOS and cost data for 73 medical and surgical DRGs. The
weighted average results of the comparison between average cost and LOS between patients
experiencing complications of tracheal injury and those not experiencing tracheal injury are
listed in Table 4 . Having tracheal injury as a complication of ETI adds an average of just over 1
day to the average length of stay (6.3 days (95% CI: 6.0-6.6) vs. 5.2 days (CI:5.1 – 5.3) and
almost $2,000 in hospital costs ($10,375 ((CI: $9,762-$10,988)) vs. $8,487 ((CI: $8,266 -
$8,669).See on-line Appendix 1 for a list of all 73 DRGs and the relative contribution to total
LOS and cost differences between patients with and those without ETI complications associated
with each DRG.
Readmissions to Repair Tracheal Injury
For our patient population of 200 who were readmitted for treatment of a previously occurring
ETI-related tracheal injury, hospital costs averaged approximately $11,025 per admission and
length of hospital stay averaged 4.7 days (Table 5). Typical procedures performed during the
readmissions included bronchoscopic treatment such as laser, electrocautery, balloon dilation,
and stenting, as well as surgical resection and reconstruction (Table 2). See on-line Appendix 2
for a summary of this analysis.
Data examining the incidence and costs associated with post-intubation tracheal injury are
sparse. Airway injury can start within a few hours after intubation.7,8 In a prospective study by
Kastanos’ group, the incidence of post-intubation tracheal stenosis (PITS) was 10%.9 Schneider
cites incidence rates of tracheal perforations from 0.005% for single lumen endotracheal tubes to
0.19% for double lumen tubes.10 Grillo et al. reported an incidence of tracheal injuries in 20
patients (3.8%) in a group of 521 patients intubated for surgical procedures.11 Likewise, Deeb
and colleagues performed tracheostomy for severe post-intubation tracheal stenosis that
prevented extubation in 1.8% (142/7600 patients).12
In our analysis, we have searched patient records for the most commonly cited tracheal
complications and procedures and have compared hospital costs and LOS for patients with and
those without documented tracheal complications, and have examined the costs of readmission
for procedures to treat the tracheal injury. Our analysis suggests that the initial tracheal injury is
associated with an increased hospital LOS of 1.1 days (6.3 days vs. 5.2 days; and an added cost
of $1,888 ($10,375 vs. $8,487) whereas readmissions to treat tracheal injury have a LOS
averaging 4.7 days and average costs of $11,025.
We excluded patients with tracheostomies from this analysis as it would be difficult to assign
causation to the endotracheal tube versus the tracheostomy tube in a patient with tracheal injury
such as tracheal stenosis or malacia. Accordingly, our criteria are likely to have excluded some
of the most costly patients requiring repair of tracheal injury caused by endotracheal intubation.
A large number of studies, going back many decades, directly associate the development of
tracheal stenosis to high cuff pressures and link the decrease in tracheal injury since the 1970s to
the development of lower pressure cuffs. Unfortunately, low-pressure cuffs can be over-inflated,
and cuff-related tracheal injury remains an ongoing problem.13-15 Other risk factors for post-
intubation tracheal stenosis include female sex (75%), obesity (66%), a history of diabetes
mellitus (35.4%), hypertension (51.6%), cardiovascular disease (45.1%), and being a current
smoker (38.7%).16 It does not appear that age is associated with the development of post-
intubation tracheal injury. In our study, the average age is nearly the same among patients with
and those without tracheal injury.
Our study has several limitations. First, this is a review of numbers extrapolated from national
databases. Given the low incidence of tracheal injury associated with endotracheal intubation,
performing a large, prospective study would be quite difficult. The ideal study would
prospectively follow all patients undergoing elective and emergent intubation, document several
variables including patient height and weight, endotracheal tube size, Mallampati classification,
type and number of airway interventions, etc. The investigators would also need to prospectively
follow these patients with airway CT scans or bronchoscopy or both, whether they were having
symptoms or not. Second, because we were not able to verify the use of ETT tubes in every
admission, it is possible that some patients with tracheal injury due to non-ETT tube factors,
such as complications of thyroidectomy, were included in our study population, despite our
stringent exclusion criteria. Third, many complications associated with endotracheal intubation
are not apparent until the patient has been extubated and has left the hospital. Additionally,
patients often do not develop symptoms of tracheal stenosis, such as exertional dyspnea, until the
tracheal lumen is approximately 8 mm in diameter, and this may take months to years to
develop.17 It is therefore probable that our study underestimates the cost associated with
readmission because we are examining readmissions during a 12-month cross-sectional
timeframe rather than a longitudinal study. Finally, the management of patients with tracheal
injury is best performed in a multidisciplinary approach.18 Many tracheal stenosis cases require
multiple minimally invasive procedures, and some patients are ultimately referred for surgical
resections.19-21 As our study examined only the costs of inpatient readmissions, the costs of these
multiple outpatient interventions are not accounted for. Similarly, the indirect costs associated
with time off from work and other such economic issues are also not addressed in our study.
Despite the limitations of our study, it is thus far the largest investigation of post-intubation
To our knowledge, this is the only study examining hospital cost and LOS following tracheal
injures due to ETI. It is important to note that in the current regulatory environment, hospitals do
not receive payment for treatment of certain complications, called “never events,” such as
catheter-related blood stream infections. In the future, it is possible that hospitals will not be
reimbursed for the additional costs associated with post-intubation tracheal injury. Although
some reimbursement is generally expected for separate hospital admissions, Medicare and other
payers are increasingly reluctant to pay extra for care needed to treat medical errors and adverse
results of hospital care.
The financial impact of post-intubation tracheal injury is significant, adding to the index
admission cost and length of stay as well as to future costs for treatment and repair of the injury.
Prospective studies are required to obtain further data about indirect costs, as well as the costs
associated with outpatient management of these patients.
This study was partially funded by a Covidien Healthcare under an agreement that the study be
conducted independently to reduce funding bias. Accordingly, the study was designed,
performed, analyzed, interpreted, and written by the investigators without the involvement,
review, or prepublication approval of Covidien.
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review of 74 cases. Ann Otol Rhinol Laryngol 2007;116:206-10.
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3. Whited RE. A prospective study of laryngotracheal sequelae in longterm intubation.
4. Gaynor EB, Greenberg SB. Untoward sequelae of prolonged intubation. Laryngoscope
5. Stauffer JL, Oslen DE, Petty TL. Complications and consequences of endotracheal intubation
and tracheostomy. A prospective study of 150 critically ill adult patients. Am J Med
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Agency for Healthcare Research and Quality, Rockville, MD. Available at:www.hcup-
us.ahrq.gov/nisoverview.jsp Accessed July 5 2008.
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Arch Pathol 1969;88:511-520.
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injuries: A retrospective analysis of 29 cases. Ann Thorac Surg 2007;83:1960-1964.
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results. J Thorac Cardiovasc Surg 1995;109:486-493.
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from prolonged intubation in adults. Otolaryngol- Head and Neck Surg 1990;120:25-9.
13. Grillo HC, Cooper JD, Geffin B et al. A low pressure cuff for tracheostomy tubes to
minimize tracheal injury: a comparative clinical trial. J Thorac Cardiovasc Surg 1971;62:898-
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17. Hollingsworth HM. Wheezing and stridor: Clin Chest Med 1987;8:231-40.
18. Brichet A, Verkindre C, Dupont J et al. Multidisciplinary approach to management of
postintubation tracheal stenosis. Eur Resp J 1999;13:888-93.
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using the endoscopic approach. Monaldi Arch Chest Dis 2007;67:73-80.
20. Macchiarini P, Verhoye JP, Chapelier A et al. Partial cricoidectomy with primary
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Table 1: Tracheal Injury Codes: ICD-9
Paralysis, vocal cord/larynx NOS
Paralysis, vocal cord unilat/ptr
Paralysis, vocal cord unilat/total
Paralysis, vocal cord bilat/prt
Paralysis, vocal cord bilat/total
Disease, larynx NEC
Trachea & Bronch Dis NEC
NEC: Note elsewhere classified
ICD: International Classification of Diseases
NOS: Not otherwise specified
Table 2: Tracheal Injury Repair Procedure Codes
Local destruction tracheal lesion
Tracheal fistula closure NEC
Tracheal repair NEC
Trachea/larynx stent replacement
Laryngeal operations NEC
Tracheal operations NEC
Respiratory tract intubation NEC
NEC: Not elsewhere classified
ICD: International Classification of Diseases
NOS: Not otherwise specified
Table 3: Specific Inclusion and Exclusion criteria for Tracheal Injury Diagnosis
Age >= 18
Tracheal Damage Diagnosis code (Table 1.) in any position other than primary diagnosis
Exclusion Criteria: From the base of adults with a qualifying diagnosis code, we excluded individuals meeting
any of the following criteria:
Diagnosis code for tracheostomy complication (519.0*) or history of tracheostomy (V44.0 or V55.0) in
any position in the discharge record
Primary diagnosis in the discharge record is a tracheal damage diagnosis code (we examine these
separately in our analysis of readmissions for tracheal damage repair)
Tracheostomy procedure code (31.1 or 31.2, 31.21 or 31.29) in any position in the discharge record
Implant procedure code (the cost of implants adds significant variability to cost comparisons and makes
cost estimates unreliable)
Cancer as a primary diagnosis (CPT codes between 140* and 208.91 in the first diagnosis position in
the discharge record)
Diagnosis code indicating cancer, cancer in situ or benign neoplasm of the throat, lungs, or other
nearby anatomical sites, in any position in the discharge record
Tracheal injury diagnosis code (874*) in any position in the discharge record
Other procedure that might have caused tracheal damage, such as a bronchoscopy, bronchial dilation,
gastroscopy, or esophagoscopy
Any procedure code we determined was most likely to be done in a readmission rather than in the
initial admission involving the ET tube
Principal Event code (ECode1) described an event which we determined was unlikely to be associated
with tracheal damage
DRG 290, 182 or 92; any of which might indicate an alternative clinical explanation for tracheal
Total Charges data unavailable or invalid in the discharge record, so hospital cost cannot be calculated.
Note: Initial analyses showed that ET tube placement was rarely coded in hospital records (procedure code 96.04).
Accordingly, we did not require documentation of the ET tube procedure code, but reviewed the data iteratively
from multiple perspectives and crafted an extensive list of criteria aimed at excluding discharges in which there
might be an alternative explanation for the conditions we identify as tracheal damage.
Table 4: Tracheal Damage: Impact on Hospital LOS and Costs for the Initial Admission
For DRGs with ≥10 eligible patients with complications
Index Cases with
Average Average Length
of Stay (ALOS)
(CI*: 5.1 –
(CI: 6.1 –
CI: 95% Confidence Interval
Source: National Inpatient Sample 2006, Healthcare Cost and Utilization Project, US Agency for Healthcare
Research and Quality. Hospital cost is estimated from total charges using hospital-specific or group average all
payer inpatient cost-to-charge ratios provided by AHRQ.
Table 5: Readmissions to Treat Previous Tracheal Injuries
Category of Index
50 81.4 30,496 10,016
61 11.7 8.1 54,633 20,905
56 6.9 2.4 16,139 6,161
52 1004.732,335 11,025
*All other conditions include vocal cord paralysis, bronchospasm, and laryngotracheal ulceration.
Appendices on line:
1_Same admit costs, los.xls
2_TD Readmission Costs.xls