Keywords
intubation - tracheostomy - airway management - respiration - oxygen saturation
Introduction
Intubation difficulties are a common issue that anesthesiologists face daily in the
operating room.[1] Difficult airways are more common in patients undergoing ear, nose, and throat (ENT)
surgery. Intensive care unit (ICU)-related tracheal intubations are potentially hazardous
primarily due to failing oxygenation and unstable hemodynamics while performing emergency
intubations.[2] In both urgent and emergency cases, ENT surgeons and anesthesiologists frequently
collaborate to perform surgeries.[3] When there is any respiratory difficulty for an unconscious patient, mechanical
ventilation is to be established by the intensive care doctors.[4]
If the intubation fails, it can result in catastrophic damage to patients, including
brain damage or death. Hence, difficult airway management in hospital settings are
tended to by a team of anesthesiologists and otolaryngologists. In nondifficult airway
management, anesthesiologists alone can manage with endotracheal tube for ventilation.
However, the role of ENT surgeons is significant to establish airway in both cases
of anticipated or unanticipated difficult airway.
Otolaryngologists usually attend the call from the emergency department to perform
elective tracheostomy on intubated patients to reduce ventilator associated pneumonia
(VAP) score.[5] However, unanticipated difficult intubation failure can result in rapid sequence
induction and respiratory compromise for which emergency surgical intervention by
an Otolaryngologist will be needed.[6] Tracheostomy ventilation is a standard procedure in cases of upper airway obstruction
and other methods like percutaneous tracheostomy and cricothyrotomy can also be used
with limited indications.
Depending on the definition used, the prevalence of difficult intubation ranges from
0.1 to 10.1%.[1] A previously conducted study reported that the incidence of patients who suffered
from difficult tracheal intubation events between 2000 to 2012 was 23% in nonperioperative
locations.[7] Another study that assessed 4,000 reports to the webAIRS anesthesia incident reporting
database reported 170 incidents of difficult or failed intubations.[8]
Tracheostomy is one of the ancient and widely used procedures in critically ill patients.
Percutaneous dilatational tracheostomy is renowned as the standard of care in the
ICU and has largely replaced surgical tracheostomy in this subset of patients.[9] High frequency jet ventilation, surgical or needle cricothyrotomy, supraglottic
airways, and cardiopulmonary bypass are the initial rescue measures in difficult airway
conditions.[10] Emergency cricothyrotomy is the final step in the “Can't intubate, can't oxygenate”
(CICO) algorithm and is performed to prevent the patient's death. Complication rates
vary by study, depending on the level of training, clinical scenario, or location
of the procedure, and can range from 0 to 54%.[11] Preintubation ultrasound has been considered for increasing the rate of successful
cricothyrotomies.[12] However, there is no gold standard for a difficult airway algorithm.[3] The primary objective of the present study is to compare and evaluate all three
methods in terms of indications, duration of operating time, intraoperative and postoperative
complications, and the instruments needed for each procedure.
Methodology
The present retrospective study was carried out at a tertiary healthcare center located
in Coimbatore, Tamil Nadu, India, between January 2013 and January 2018. Data was
collected from case sheets obtained from the medical record section of the emergency
department and ICU. Prior to initiation of the study, ethical clearance was obtained
from the institutional ethics committee (PSG/IHEC/2020/App/Exp/234). All study procedures
were conducted by trained otolaryngologists employed at the hospital.
Study population: The total number of cases examined was 582 and, from these, 85 patients suffered
from difficult intubations or failed intubations and needed an airway for further
management and these patients were included in the present study. Patients with easy
ventilation with endotracheal tubes without tracheostomy were excluded from the study.
Interventions
The present study compared three methods, tracheostomy,[13] percutaneous dilatational tracheostomy,[14] and cricothyrotomy[15] for factors such as duration of the procedure, complications (earlier and late),
and instruments needed for each procedure. All three procedures were performed by
an otolaryngologist during the emergency calls. All calls were attended by different
ENT surgeons.
All suspected cases of difficult airway underwent fiberoptic laryngoscopic examination.
First, nonsurgical techniques like intubation were performed. If two consecutive attempts
failed, oxygen saturation was maintained by means of face mask ventilation until an
airway was established through surgical technique/intervention. The instruments used
and the time taken for each procedure were described in [Table 1].
Table 1
Comparison between different procedures
|
Method
|
Instruments
|
Operating time
|
|
Tracheostomy
|
Special set of instruments includes knife, monopolar cautery, langenberg retractor,
tracheal dilator, alice forceps
|
10-15 minutes
|
|
Percutaneous tracheostomy
|
Separate kit which includes a 22-gauge needle and syringe; 11-F short punch dilator;
1.32-mm 28-F, 32-F, 36-F, and 38-F dilators; Shiley no.6 tracheostomy tube guidewire;
8-F guiding catheter; 18-F, 21-F, 24-F,
|
10-15 minutes
|
|
Cricothyrotomy
|
Scalpel or 15 blade. Tracheostomy tube 6 size
|
1-3 minutes
|
According to the 2016 American Society of Anesthesiologists (ASA) physical status
classification system practice guidelines, the anesthesiologist should have a preplanned
strategy for intubation of the difficult airway.[16] Surgical technique can be the best option to be considered for difficult intubation
cases as it is a lifesaving procedure and ENT surgeons should have expertise in proper
selection of the technique to be employed and resultant success at establishing airway
in failed intubation cases.
The two procedures that were conducted as part of the study are:
Tracheostomy:[13] The tracheostomy procedure was first documented in history around 1546 B.C. for
peritonsillar abscess cases to relieve resultant airway obstruction. Except for cases
of impending airway obstruction, tracheostomy is performed on an elective basis for
patients who require long-time ventilation. It is an opening in the anterior wall
of the trachea holding the tracheostomy tube for an alternate pathway of breathing
in case of individuals with upper airway obstructions. Usually in ICUs, early transition
to tracheostomy (ETT) is a procedure recommended by anesthesiologists in order to
reduce the incidence of VAP. This emergency procedure is performed under local anesthesia
on patients exhibiting supraglottic obstruction with stridor. Ideally, the tracheostoma
should lie over the 2nd to the 3rd tracheal ring cartilages. High tracheostomy can lead to subglottic stenosis and low
tracheostomy can result in possible injury to the pleura. Since this is an open procedure,
it is essential to avoid complications, and this is easily manageable. The vertical
incision is made 2 to 3 cm inferior to the cricoid, which makes it unlikely that we
encounter any vascular structures. Skin and strap muscles are retracted, the isthmus
of the thyroid is lifted by a hook, and the anterior tracheal wall is incised after
which the tracheostomy tube is inserted through the opening. Cuffed tubes are ideal
for mechanical ventilation to facilitate positive pressure ventilation.
Percutaneous tracheostomy:[14] The challenges of airway establishment also depend upon the operating room time
and on the burden of transporting critically ill patients, which was the impetus behind
developing a quick, safe, and reliable alternative to open tracheostomy. Toye et al.[17] first described percutaneous tracheostomy using the Seldinger technique in 1969,
and remained in practice until Ciaglia[18] introduced the dilatational percutaneous technique in 1985. The surgeon should recognize
that all patients are good candidates for PDT but it is contraindicated in children
because the trachea is collapsible, mobile, and difficult to localize for safe performance.[19] It has also been reported as a contraindication in children according to a study
by Kost as well as to a review conducted by Cho.[20]
[21] Obese individuals should also be managed with special care as thyroid swelling is
also a contraindication for this procedure. The most commonly used technique for PDT
was first described by Ciaglia et al., which was a bedside technique in which the
guide wire was passed between the 2nd and 3rd tracheal rings. Sequential dilatation using graduated dilators over the guidewire
created a passage through which the tracheostomy tube is placed.[22] Since it is a form of blind procedure, the chances of posterior tracheal wall injury
are present but can be prevented by adopting videobronchoscopic guidance as needed.[23]
Cricothyrotomy:[15] Difficult airway sentinel events occur in critical care departments due to lack
of coordination between specialty providers, difficulty in access to equipment to
address the airway management at bedside and unavailability of training/experience
on the respective procedure. Only ENT surgeons can perform this procedure with minimal
requirement of instrumentation.
Despite the introduction of numerous rescue devices for failed airway, the most common
errors in the management of difficult airway are the result of repeated and consecutive
unsuccessful attempts at intubation. Once identified as a CICO situation, immediate
cricothyrotomy is the ideal surgical intervention to be performed by an otolaryngologist
and should be practiced accordingly. In order to prevent hypoxic brain injury, early
airway establishment by this technique is to be considered as the best option, hence,
it is a highly recommend practice. However, the main obstacle is certainly lack of
experience or failure in recognizing the timely need to perform this procedure.
The following are the important rapid five steps of the technique:[15]
-
Extend the neck and identify the thyroid angle and fix the cartilage.
-
Make a vertical skin incision with a 15G blade after palpating the lower border of
the thyroid cartilage and extend 2 mm below it.
-
The blade should be inserted perpendicularly through the cricothyroid membrane (CTM).
-
Insert a clamp to spread and elevate the airway.
-
Insert a smaller sized tracheostomy tube or a smaller sized ETT and immediately inflate
the cuff
The anatomical structures to be considered during the procedure include:
Surgical anatomy of the cricothyroid membrane:
[24] The CT) is bordered superiorly by the thyroid cartilage, inferiorly by the cricoid
cartilage, and laterally by the bilateral cricothyroideus muscles. It is a fibroelastic
triangular membrane. Its upper border is free and stretches between the thyroid angle
to the vocal process of the arytenoids and forms the vocal ligament. Its lower border
attaches to the arch of the cricoid cartilage.
Dimensions of the cricothyroid membrane:[25] In an average adult male, it is 1 cm in length and 2 to 3 cm wide and is in the
midline about a fingerbreadth below the laryngeal prominence. The vocal folds are
∼ 1 cm above the CTM and therefore prone to injury during this procedure. The ligament
does not calcify. The anterior part of the conus elasticus is the middle cricothyroid
ligament (ligamentum cricothyreoideum medium; central part of the cricothyroid membrane).
It is thick and strong, narrow above and broad below. It connects the front parts
of the contiguous margins of the thyroid and cricoid cartilages. It is overlapped
on either side by the cricothyreoideus, but subcutaneous in between; it is crossed
horizontally by a small anastomotic arterial arch, formed by the junction of the two
cricothyroid arteries, whose branches pierce it.
Vascular anatomy of the cricothyroid membrane:[26] The cricothyroid artery crosses the upper one-half of the cricothyroid membrane.
Branches of the cricothyroid artery penetrated the membrane and ascended along the
under surface of the thyroid cartilage. The superior thyroid artery coursed anterior
to the sternothyroid muscle and then the lateral edge of the cricothyroid membrane.
The membrane was also crossed by venous tributaries to the superior and inferior thyroid
veins.
Instruments for Various Procedures:
-
Conventional tracheostomy: Tracheostomy instrument set including tracheal dilator,
artery forceps, and retractors.
-
Percutaneous tracheostomy: Separate special kit, video bronchoscope
-
Cricothyrotomy: Scalpel, artery forceps, cuffed ETT, or tracheostomy Tube
Result
The study recruited 85 patients, consisting of 61 males and 24 females, with an age
ranging between 30 and 70 years old. [Fig. 1] illustrates the distribution of patients for three different procedures. Most participants
consisted of unconscious ICU patients. [Table 1] elaborates the comparison of instruments needed for each procedure and the time
required. To perform cricothyrotomy, only a simple blade was required. The procedure
was completed within 1 to 3 minutes, which was the least compared to tracheostomy
and percutaneous tracheostomy. However, to perform tracheostomy and percutaneous tracheostomy,
special kits were used and the time taken to complete these procedures was from 10
to 15 minutes.
Fig. 1 Distribution of patients for three different procedures.
[Table 2] illustrates the comparison of different procedures based on operating time, intraoperative
complications, and time of full oxygen saturation. The operating time (4.1 ± 3.1minutes)
and time of full oxygen saturation (3 minutes) were observed in cricothyrotomy. The
least bleeding was observed in percutaneous tracheostomy (1%).
Table 2
Comparison of different procedures (based on operating time, intraoperative complication,
and time of full oxygen saturation)
|
Operating time
|
Intra-operative complication
|
Time of full oxygen saturation
|
|
Conventional tracheostomy
|
12.78 ± 3.18 minutes
|
• Bleeding 3%
• Subcutaneous emphysema 2%
|
10-15 minutes
|
|
Percutaneous tracheostomy
|
18.38 ± 3.3 minutes
|
• Bleeding 1%
• False track 2%
|
10-15 minutes
|
|
Cricothyrotomy
|
4.1 ± 3.1 minutes
|
• Bleeding 3%
|
3 minutes
|
[Table 3] depicts a comparison of different procedures based on intraoperative bleeding. The
intraoperative bleeding was graded from 0 to 5. It was noted that cricothyrotomy significantly
showed the least intraoperative bleeding than percutaneous dilation tracheostomy and
tracheostomy (t = ,12.588664; p < 0.001).
Table 3
Comparison of different procedures (based on intraoperative bleeding)
|
Intraoperative bleeding (Grade: 0–5)
|
t-value
|
p-value
|
|
Conventional tracheostomy
|
1.4 ± 1.04
|
12.588664
|
< 0.001
|
|
Percutaneous tracheostomy
|
3.5 ± 0.9
|
|
Cricothyrotomy
|
3.0 ± 0.5
|
[Table 4] shows that 10 patients who underwent tracheostomy suffered from subcutaneous emphysema,
4 patients who underwent percutaneous tracheostomy underwent severe bleeding, and
1 patient who underwent cricothyrotomy suffered from moderate bleeding. Tracheostomy
and percutaneous tracheostomy took 10 to 15 minutes to provide access to airway while
cricothyrotomy took 3 minutes.
Table 4
Analysis of complications
|
Activity
|
Complication
|
Time to access airway
|
|
Tracheostomy
|
Subcutaneous emphysema – 10 patients
|
10-15 minutes
|
|
Percutaneous tracheostomy
|
Severe bleeding – 4 patients
|
10-15 minutes
|
|
Cricothyrotomy
|
Moderate bleeding – 1 patient
|
3 minutes
|
Discussion
Cricothyrotomy and percutaneous dilatational tracheostomy placement are important
means of securing an artificial airway in patients with acute or chronic respiratory
failure.[27] Despite advances in airway management techniques and refinement of difficulty predictors,
the cited 1 to 3% unanticipated difficulty has not been changed, making the role of
the otolaryngologist essential. In a quest to determine which procedure can be used
for a difficult airway, the present study aims to focus on enlightening the elective
and emergency procedures performed for difficult airway conditions. To the best of
our knowledge, this is the only study that compared all three procedures and evaluated
all three methods in terms of indications, duration of operating time, intraoperative
and postoperative complications, and the instruments needed for each procedure.
Data from 85 patients were evaluated, out of which the majority of the patients were
males (71.1%). The age of the patients ranged between 30 and 70 years old. This was
aligned with Wnent et al., who also reported that the predictive factors for impossible
intubation were male gender and younger age.[28] Endlich et al. reported that the prevalence of difficult and failed airway intubation incidents
mostly occurred in patients aged between 40 and 59 years old.[8]
Out of 85 patients, the maximum number of patients underwent conventional tracheostomy.
This may be because cricothyrotomy and percutaneous dilatational tracheostomy procedures
are expensive compared to conventional tracheostomy. Moreover, these procedures require
a lot of skill development.[29]
Percutaneous tracheostomy and cricothyrotomy cases were low in number to assess its
significance. This was due to patients suffering from cervical spine injuries being
difficult to shift to the operation theatre; patients who underwent percutaneous tracheostomy
were under high level of respiratory support. Cricothyrotomy was done in situations
where intubation and oxygenation were not possible in order to improve saturation
with quick access. The knowledge of cricothyrotomy and adequate training are key factors
for the success of this procedure.
Four of the patients who underwent percutaneous tracheostomy died due to comorbidities,
with the remaining 11 patients undergoing successful decannulation. All cricothyrotomy
patients were changed to conventional tracheostomy after successful airway access
on the same day and the cricothyrotomy wound was closed. Postoperative follow-up was
done for 1 year, no subglottic stenosis was noticed, and successful decannulation
was done for 7 patients. One patient went against medical advice.
The present study also compared the instrument and the time taken to complete the
procedure by three methods: cricothyrotomy, percutaneous dilation, and tracheostomy.
The simplest and easily available instruments that were used among the three procedures
were scalpel or 15 blades for cricothyrotomy, and it can take only 1 to 3 minutes
to complete the procedure. Technically, an emergent cricothyroidotomy is not a difficult
procedure. However, it may be prohibitive to the unprepared team from a cognitive
standpoint.[11] On the other hand, percutaneous tracheostomy requires a separate kit requiring a
gauge needle and syringe, short punch dilator, Shiley no.6 tracheostomy tube, guide
wire, and guiding catheter. It takes almost 10 to 15 min to complete the procedure.
Percutaneous tracheostomy is a safe and cost-effective procedure used in patients
who require prolonged mechanical ventilation, most commonly in the ICU.[27]
In the present study, cricothyrotomy took the least operating time (4.1 ± 3.1minutes).
In the previous study conducted by Anasuya et al., to perform a cricothyroidotomy procedure, it took 75 to 180 seconds. A cricothyrotomy procedure would need a simple blade; as a result, it can be completed
without wasting time.[30] The time of full oxygen saturation reported for cricothyrotomy was 3 minutes. A
study by Chen et al. showed that SpO2 was increased postoperatively, reaching 95% at 12 seconds, 131 seconds,
and 144 seconds in the cricothyroid membrane puncture guided tracheostomy (CMPGT),
surgical cricothyroidotomy (SC) and Griggs guidewire dilating forceps (GWDF) groups,
respectively.[31]
Among all aforementioned procedures, the least amount of intraoperative bleeding was
noted in cricothyrotomy, and this was assessed by calculating the number of soaked
gauzes. For most patients who require an emergency surgical airway, cricothyrotomy
is preferable to tracheostomy because it is easier to perform, causes less bleeding,
and takes less time to perform than an emergency tracheostomy.[11] The only obstacle is the lack of experience or timely recognition of the need to
perform this procedure.[29]
The advantages and features of cricothyrotomy over other procedures are that no major
vessels intervene in the cricothyroid membrane area, the localization is easy in patients
with thin necks, it can be performed in obese patients by sliding the finger from
the thyroid angle and feeling the lower border of the cartilage in the midline, rapid
entry, and placing the tracheostomy tube and inflating the cuff immediately will prevent
both bleeding and subcutaneous emphysema.
The limitation of the present study was the retrospective nature of the study which
can result in information bias. Another limitation was that cerebral hypoxia improvement
was not assessed or compared. The operating surgeon was a confounding factor, although
it was reduced by including a surgeon with the same level of straining and experience
in all procedures. Males outnumbered females in all groups. Although it was difficult
to exactly estimate the amount of intraoperative blood loss, we adopted the surgical
field method as well as graded the intraoperative bleeding both reported by a surgeon
for assessment of imperative bleeding. Future studies should aim to include a large
number of patients and should include a detailed postoperative review.
Conclusion
All three procedures, tracheostomy, percutaneous dilatational tracheostomy, and cricothyrotomy, can be
used for maintaining airway procedure in various conditions. However, our study recommended
tracheostomy and percutaneous tracheostomy as suitable techniques in difficult intubations
but with oxygen saturation maintained with an oxygen mask. In desaturating and difficult
cases that represent the CICO scenario, cricothyrotomy is the gold standard procedure,
as it takes less time to perform, causes less bleeding, and takes the least time for
full oxygen saturation than tracheostomy and percutaneous dilatational tracheostomy.
