Comparison of Nasogastric tube insertion using conventional technique versus compression of soft tissues technique in intubated patient

A nasogastric tube is a flexible tube designed to pass through the nasal cavity into the gastric cavity. It is used for providing nutrition and medication in intubated patients (e.g., conditions with dysphagia such as head and neck cancers, altered mental status, etc.) and gastric decompression to relieve pressure (e.g., patients undergoing abdominal laparoscopic surgery) and decompression (e.g., after ingestion of harmful poisons such as organophosphorus poisoning, gastric outlet obstruction and small bowel obstruction).  [1-5]

Numerous techniques are available for Nasogastric tube insertion with variable first pass success rates ranging between 63%-76%, such as forward displacement of the larynx, lateral rotation of the neck, use of a split endotracheal tube, use of various kinds of forceps, etc. [6-9]  Various reasons are attributed for failure in insertion at the first attempt, such as Intraoral coiling due to inability of the patient to swallow, presence of an inflated cuff in the proximal trachea, fall of oesophagus onto the posterior pharyngeal wall, causing mechanical obstruction. [10] The nasogastric tube multi-aperture distal part often makes it susceptible to kinking and coiling, with mucosal tears with resultant bleeding. Impaction at the arytenoids and pyriform fossae is another common occurrence. [6] Hence, we have to adjust our manoeuvres to slide the nasogastric tube along the posterior pharyngeal wall to facilitate a smoother passage into the oesophagus.

Nasogastric tube insertion is associated with numerous complications, such as injury to nasal turbinates, oesophagus, or gastric mucosa, leading to mucosal tears and bleeding. It is also associated with sinus infection and electrolyte imbalances such as hypokalemia. [6] Rarely, Nasogastric tube insertion may result in accidental placement of the NGT in the airway, causing infiltration of the lungs. [11]

We have described and used a novel technique for NGT insertion called Compression Of Soft Tissues (COST). We hypothesise that by compression of Soft tissues in the floor of the mouth, the tongue is approximated with the hard and soft palate. This decreases intraoral space, reduces intraoral coiling of the nasogastric tube and improves the success rate of insertion in the first attempt. We have planned to compare our novel COST technique with the conventional (CONT) technique of NGT insertion with the head in a neutral position in anaesthetised and intubated patients undergoing abdominal surgery. We aim to determine their success rate, time taken for insertion and incidence of any complications such as bleeding and coiling.

AIMS AND OBJECTIVES

  This study will aim to investigate the difference in the first-attempt success rates, time taken for insertion, and complication rates between the two different techniques for the insertion of a nasogastric tube.

Primary objective:

·       To compare the First pass success rate between the two techniques.

Secondary objectives:

·       Time taken for insertion

·       Causes for failure (Coiling,, kinking overinflated ETT cuff)

·       Incidence of any Complication associated with NGT

After procuring informed written consent, all the patients included in the study will be randomised using a computer-generated random table into one of two groups: Group CONT (insertion using conventional technique) and Group COST (insertion using compression of soft tissues technique).

Following airway measurements will be noted in the preoperative period: Sterno-mental distance(SMD), Sterno-xiphoid distance (SXD), and body mass index (BMI).

On the patient’s arrival to the operating room, a peripheral venous catheter will be established; Standard monitors will be attached. General anaesthesia induction will be standard with intravenous fentanyl 2mcg/kg, propofol 2mg/kg and atracurium 0.5mg/kg. An appropriate-sized endotracheal tube will be inserted into the trachea under direct laryngoscopy.

Nasogastric tube insertion technique: In both groups, the head of the patient will be kept in a neutral position without any flexion or extension. A well-lubricated 14 Fr NGT will be used for insertion.

Group CONT: In this group, using the dominant hand of the person performing the procedure, a lubricated NGT will be inserted in the patent nostril up to a premeasured length (SMD+SXD). No other manoeuvre will be used to aid in the insertion.

Group COST: In this group, using the non-dominant hand of the person doing the procedure, soft tissues under the mandible will be compressed so that the tongue is approximated onto the hard and soft palate. Then, with the dominant hand, a lubricated NGT will be inserted through the patent nostril into the gastric cavity. No other manoeuvre will be used to aid in the insertion.

Confirmation of the gastric placement of NGT will be done by using the Syringe-woosh test (injection of 10ml of air via a nasogastric tube with simultaneous auscultation over the epigastrium). The technique will be considered a success if the Syringe-woosh test is positive (successful auscultation of injected air over the epigastrium). Similarly, it will be regarded as a failure if the Syringe-woosh test is negative (failure to auscultate injected air over the epigastrium).

If the first attempt fails, the NGT will be fully withdrawn, cleaned, and lubricated, and the procedure will be repeated using the same technique without any additional manoeuvre. If two attempts for insertion are unsuccessful, the selected technique will be considered as an overall failure. In case of two failed attempts, NGT will be inserted with the assistance of a laryngoscope and Magill forceps under direct vision.

Bleeding due to trauma will be confirmed by blood staining of the nasogastric tube after removal or blood in the nasal cavity/oral cavity. Prophylactic laryngoscopy will be done to check for intraoral bleeding after confirmation of accurate placement of the nasogastric tube.

The following parameters will be noted:

Success rate of selected technique (first attempt, second attempt, overall)

Time taken for successful insertion

Complications of the procedure such as kinking, coiling or bleeding.

 Statistical Analysis;

Categorical variables will be expressed as numbers and percentages. Data will be expressed as mean (± SD) or as median (± interquartile range) when appropriate.

 Outcome parameters:

 Â·        Primary outcome: Firsts attempt success rate

·        Secondary outcomes:

o    Number of attempts needed to insert nasogastric tube

o    Time for insertion

o    Bleeding incidence

o    Complications associated with NGT

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