SYNOPSIS
Title:
Comparison of the
ease of Nasogastric tube insertion in standard sniffing position and further
flexion.â€
Background:
Nasogastric tube insertion is a common/mandatory procedure
for all major surgical procedures, sometimes it is technically challenging
particularly in anesthetised , paralyzed,
and intubated or unconscious patients with reported failure rates of nearly 50%
on the first attempt with the head in neutral position.(1-3)
After a failure, subsequent attempts are usually unsuccessful due to coiling,
kinking, or knotting of the NG tube as it loses stiffness due to warming to
body temperature. The memory effect also contributes to subsequent failures;
once kinked, the NG tube is subsequently more likely to kink at the same place.
It has been acknowledged that most difficulties in NGT insertions are due to
anatomic reasons(4).
The most common sites of impaction of the NG tube are piriform sinuses, the
arytenoid cartilage(5)
and the esophagus, which becomes compressed by the inflated cuff of an
endotracheal tube. Maneuvers to keep the NG tube along the lateral or posterior
pharyngeal wall during insertion encourages the smooth passage into the
esophagus.(1, 2, 4). Common
methods used to facilitate NG tube insertion include the use of a slit
endotracheal tube, forward displacement of the larynx and the use of various
forceps, the use of an ureteral guidewire as a stylet, head flexion, lateral
neck pressure, and the use of a gloved finger to steer the NG tube after
impaction.(2, 6-8) So
far there are no guidelines/protocols/position for its insertion.
We hypothesized that slight modifications in NG tube
insertion technique would improve the rate of successful insertion. We want to
study the ease of insertion of NG tube with the head in sniffing position in
the first group and in second group the neck will be further flexed by using
additional pillow . This study will be unique in nature where it will study the
ease of insertion in two different positions sniffing and in further flexion
positions and may guide the insertion in difficult scenarios.
AIM
To compare the ease of insertion of NG Tube between the
standard sniffing position and in further neck flexion using an additional
pillow. we determine the success rate,
average time for insertion.
Secondary end point being incidence of complications, such
as bleeding, coiling and kinking.
METHODS
This is a randomized, observational study wherein, one
hundred patients will be enrolled. The patients will be randomized into two
groups by computer generated random numbers.
Group 1: Here the NG tube will be inserted in the standard
sniffing position.
Group 2: the NG tube
is inserted with neck flexed using an additional head ring, then the tube is
taken out and reinserted with the head in standard position, i.e with a single
head ring. The starting point of the procedure is the time when NG tube
insertion is begun. The end point is the time when there is successful
insertion of the NG tube.
Failure is defined as:
1.
Not able to insert the tube in 2 attempts,
2.
Using more than one alternative technique such
as jaw lift, laryngeal lift, use of laryngoscope, magills,
3.
Time more than 30 sec.
The success rate of the technique, duration of insertion
procedure, and the occurrence of complications (bleeding, coiling,) are noted.
Inclusion criteria:
Patients coming for
elective surgeries, requiring insertion of NG tube and are
ASA I or II
Age 18 - 65 years
Exclusion criteria:
ASA status III, IV,
Pregnant patients
Patients with risk of
pulmonary aspiration of gastric contents,
Patients requiring rapid
sequence induction,
Patients with cervical spine
pathology,
Patients on anticoagulants or on aspirin
Patients with neck mass,
Patients
with raised intracranial tension,
Patients with
gastro-esophageal reflux disease and
Patients with airway distortion or trauma will
be excluded from the study
A detailed preoperative assessment with respect to history and
examination will be performed. The patients age, sex, weight, height, body mass
index (BMI) will be noted, along with the presence of any comorbidities. The
following airway assessment measurements will be noted.
1.
Thyro
mental distance - It is defined as the distance from the mentum
to the thyroid notch while the patient’s neck is fully extended. This
measurement helps in determining how readily the laryngeal axis will fall in
line with the pharyngeal axis when the atlanto-occipital joint is extended.
Alignment of these two axes is difficult if the T-M distance is < 3 finger
breadths or < 6 cm in adults; 6-6.5
cm is less difficult, while > 6.5 cm is normal.
2.
Sterno
mental distance- It’s the
distance from the suprasternal notch to the mentum. It is measured with the
head fully extended on the neck with the mouth closed.
3.
Neck
circumference- It is the
circumference of the neck at the level of thyroid cartilage.
4.
Body
mass index: calculated as
the weight in kilograms divided by the square of the height in meters. Obesity
is defined as a body mass index greater than 30kg/m 2 .
5.
Modified
Mallampatti grading-
The
Mallampatti classification correlates tongue size to pharyngeal size. This test
is performed with the patient in the sitting position, head in a neutral
position, the mouth wide open and the tongue protruding to its maximum.
Anaesthetic management:
All the patients will be premedicated with Alprazolam 0.5 mg and
Ranitidine 150mg night before and on the morning of surgery.
In the operating room, baseline HR, SBP, DBP and SpO2 will be monitored.
After obtaining iv access, Inj.
glycopyrrolate 0.1mg intravenous 5 minutes before the induction will be given.
Analgesia will be provided with Inj. fentanyl 2mcg/kg intravenously. All the
patients will be preoxygenated with 100% oxygen for 3 minutes. Standard
induction included Inj. thiopentone 4mg/kg intravenously or till the loss of
eyelash reflex and Inj. atracurium 0.5 mg/kg intravenously for muscle
relaxation. Using a laryngoscope, intubation will be performed with appropriate
sized endotracheal tube.
Then the NG tube will be inserted according to the random group that the
patient has been assigned.
Group 1: The NG tube is inserted in the standard sniffing
position with a single head pillow. In group 2 the head will be further flexed
with an additional head pillow and then the nasogastric tube will be
inserted. The ease of insertion will be
assessed by the following
The starting point of the procedure is the time when NG tube
insertion is begun. The end point is the time when there is successful
insertion of the NG tube.
The following manoeuvres will be used if NG tube if unable to insert in first attempt
First Jaw lift
Laryngeal lift
Use of ureteral guide wire
Use of Magills forceps
Change of nostril.
The success rate of the technique, duration of insertion
procedure, and the occurrence of complications (bleeding, coiling,) are noted.
Failure is defined as:
1.
Not able to insert the tube in 2 attempts,
2.
Using more than one alternative technique such
as jaw lift, laryngeal lift, use of laryngoscope, magills,
3.
Time more than 30 sec.
Data collection:
Airway measurements will be noted during the pre anaesthetic
check-up. After induction of anesthesia Nasogastric tube insertion will be
performed and the time taken for insertion, need for additional manoeuvres,
presence of any complications will be noted.
Data analysis:
The time taken for insertion, need for additional
manoeuvres, presence of any complications will be noted and statistical
analysis will be done using SPSS version 17.1.
References
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R. Another method to assist nasogastric tube insertion. Canadian journal of
anaesthesia = Journal canadien d’anesthesie. 2005;52(6):652-3.
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JL. Oro- and nasogastric tube passage in intubated patients: fiberoptic description
of where they go at the laryngeal level and how to make them enter the
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Carter SR. An alternate method for nasogastric tube insertion. Anesthesiology.
1980;53(5):436.
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