Nasogastric Tube Insertion in Anesthetized Intubated Patients Undergoing Laparoscopic Hysterectomies: A Comparative Study of Three Techniques.

BACKGROUND: Insertion of a nasogastric tube (NGT) in an anesthetized, comatose intubated patient is not always as easy as in a conscious, cooperative patient. Various techniques have been tried with varying success. The aim of this randomized study was to compare and evaluate the two techniques of NGT insertion with the conventional technique of insertion with respect to success rate, time taken for insertion and adverse effects.
MATERIALS AND METHODS: Patients admitted for laparoscopic hysterectomy were chosen and then were divided into three equal groups of forty each, by randomized technique. Group C included patients in whom conventional method was used to insert NGT. Group R where reverse Sellick's technique was used. Group F where neck flexion with lateral pressure was used.
RESULTS: Both the techniques were better than the conventional method. Among both the techniques, reverse Sellick's technique was the best method but not without adverse effects. The required insertion time was very less and success in the first attempt was more in the group where reverse Sellick's was used.
CONCLUSION: Modified techniques of NGT insertion were better than the conventional method. Further studies after eliminating major limitations are required to really find a superior technique.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Nasogastric tube (NGT) insertion is one of the most frequently performed procedures in patients with wide range of diseases and conditions, from very healthy subjects undergoing elective surgeries to critically ill intubated patients. NGT helps to deflate the stomach which obscures the view of the camera during laparoscopic surgery also, chances of gastric perforation is minimized by NGT insertion. However, insertion of an NGT in a critically ill patient or an anesthetized patient who cannot swallow is a very challenging procedure. In anesthetized and intubated patients, the NGT gets coiled in oral cavity due to inability to swallow and the presence of an inflated cuff in the proximal trachea. Furthermore, flexible structure of the NGT may also be a cause to coiling and unsuccessful placement. Nonopposing lateral eyes like opening near the tip may provoke kinking of NGT.[1]

An average failure rate of nearly 50%–66% was reported on the first attempt made by conventional method with the patient's head in an intubating position.[23] It has been acknowledged that most difficulties in NGT insertions are due to anatomic reasons.[4] The most common sites of impaction are the pyriform sinus, the arytenoids cartilage,[45] and the esophagus, which becomes compressed by the inflated cuff of an endotracheal tube.

Previous studies have described different techniques for facilitation of NGT insertion such as the use of intubation stylet,[1] endotracheal tube-assisted technique,[6] endoscopic technique,[7] the use of frozen NGT,[8] use of “peel-away” split tracheal tube,[9] angiography catheter guided technique,[10] and esophageal guidewire-assisted technique.[11]

NGT insertion has also been associated with many adverse outcomes sometimes if not inserted properly. Aspiration pneumonia, nasal mucosal bleeding, intracranial placement, esophageal and other enteric perforation, hypertension, tachycardia, arrhythmia, bronchial placement, pneumothorax, hydrothorax, empyema, and vascular penetration are a few to mention.[1812131415]

Modifications have been tried with conventional techniques. With several methods of insertion and variable success rates, the search for the best technique is still on. The objectives of this study are to evaluate two modified techniques of NGT insertion in comparison with the conventional method with respect to success rate, time for insertion and the adverse events such as kinking, bleeding, coiling, and failed procedure.

MATERIALS AND METHODS

Permission from the institutional ethics committee was obtained before starting the study. The patients scheduled for laparoscopic hysterectomy, aged 20–70 years with the American Society of Anesthesiologists physical status Class I and II with normal airway (Mallampati Grade 1 or 2) requiring NGT insertion were recruited for the study. A total of 120 patients were included in the study, and they were randomly divided into three groups by simple sealed envelope technique. Patients who had significant deformities of chin, pharynx and/or larynx, the base of skull lesion, upper airway lesion, abnormal prothrombin time, activated partial thromboplastin time and platelet disorder, esophageal stenosis or varices, and a history of radiotherapy in the head and neck region were excluded from the study. Informed consent was obtained from each patient after discussion of the study procedure and expected complications. Considering an α value of 0.05 and power of study (1−β) at 80%, a minimum sample size of forty patients was necessary for each group. No excluded cases were there.

Thus, patients were divided into three groups with forty patients in each group. Patients in Group C belonged to control group. Group R included patients in whom reverse Sellick's maneuver was used for NGT insertion. Group F included patients in which neck pressure with lateral flexion method was used for NGT insertion.

After admission, preanesthetic evaluation of the patients was done. Before induction of anesthesia, the optimum nostril for NGT insertion was chosen based on the better fogging produced on a metal tongue depressor during exhalation. After premedication with glycopyrrolate (0.01 mg/kg), midazolam (0.03 mg/kg), tramadol (1.5 mg/kg), and lignocaine (1.5 mg/kg), the patient was induced with thiopentone (5 mg/kg), or propofol (1.5 mg/kg). Intubation was performed with a cuffed endotracheal tube (7–8 mm internal diameter as per patient's size) using atracurium (0.5 mg/kg). After tracheal intubation, oxymetazoline (0.05%) drops was instilled into both the nostrils. Sterile, lubricated, 14F, NGT was used.

In the control group (Group C), a lubricated NGT insertion was performed through the selected nostril, the head being maintained in a neutral position. In the neck flexion with lateral neck pressure group (Group F), a lubricated NGT was inserted through the selected nostril to a depth of 10 cm. Lateral neck pressure was applied at the same side as that of the selected nostril with the neck flexed and the NGT was advanced in a similar manner to that described for Group C. In the reverse Sellick's maneuver group (Group R), anterior displacement (lifting) of the cricoid cartilage was done to facilitate the insertion of NGT.

The time taken for insertion (in seconds) was calculated from the initiation of NGT insertion through nostril up to successful placement of NGT within two attempts. This was measured with a stopwatch. If both attempts were unsuccessful, then the technique was considered a “procedure failure.”

The correct placement was confirmed with auscultation method. The following data were collected number of attempts for successful NGT insertion, procedure time, and adverse events during insertion such as kinking, coiling, and bleeding

RESULTS

A total of 120 patients were enrolled into the study. A total of 40 patients were randomly selected to be included in each of the three groups. The baseline characteristics of the patient are tabulated in Table 1. There was no statistical difference between the groups with respect to age (P = 0.7667) and height (P = 0.0531) of the patients.

Table 1

Baseline characteristics of the study population

At the first attempt, highest success rate (77.5%) was seen in Group R where reverse Sellick's maneuver was used to insert NGT. In the second attempt, success rate was more in the Group C and Group F. In both the groups, success rate was 37.5% in the second attempt. The failure rate was highest in the Group C (25%) where the conventional method was used to insert the NGT [Table 2].

Table 2

Comparison of success and failure rates among the three groups

Insertion time was very less in Group R which required only 13.05 ± 2.57 s. Group F required 20.48 ± 4.69 s. Group C, conventional group, required the longest time for NGT insertion. Group C required 25.55 ± 4.52 s [Table 2].

Thus, there was high failure rate and long insertion time in the conventional group when compared to Group R and Group F which are modifications of the conventional procedures [Table 2].

The complications seen during the NGT insertions were noted and tabulated in Table 3. The most common complication seen in Group C was coiling, which was seen in 25 patients (62.5%), bleeding in 12 patients (30%). In Group F, coiling and bleeding were seen in 12 patients (30%). In Group R, bleeding was the most common complication which was seen in ten patients (25%), followed by coiling in seven patients (17.5%). Kinking was seen in three patients (7.5%) in all the three groups.

Table 3

Complications during the procedure among the three groups (original)

DISCUSSION

This study showed that patients who were inserted with NGT using conventional technique had low success rate and more complications.

In this study, a higher success rate for the NGT insertion was observed in Group R (reverse Sellick's maneuver) followed by Group F (neck flexion with lateral pressure) when compared with Group C (conventional group). In reverse Sellick's maneuver, the cricoid cartilage is lifted anteriorly, which helps in opening esophagus thus easing the insertion of the NGT. Neck flexion helps in keeping the NGT near the posterior pharyngeal wall which helps in inserting the NGT easily into the esophagus. Lateral pressure is applied along with neck flexion. Lateral pressure causes the collapse of the pyriform sinus of the same side and medial displacement of the arytenoid cartilage.[16] This anatomical displacement causes easy movement of the NGT into the esophagus.

The findings in this study are similar to a study done by Appukutty and Shroff[3] where they found that modifications of the conventional procedure were better than routine procedure. In conscious and cooperative patients, NGT insertion is done by “Push and Swallow” technique.[17] However following this same procedure in a conscious patient does not always end in success. Such a routine procedure in a conscious patient may sometimes be frustrating as there may be more failures. The failures are because the NGT may get impacted in the pyriform sinus, arytenoid cartilage or trachea.[4] Kinking, coiling, and sometimes entanglement complicate the situation.[18] If accidentally NGT goes into the tracheobronchial tree, it may cause pneumothorax, hemothorax, or even death.[19] If it coils in the epiglottis, it may cause respiratory distress, choking episodes, tachypnea, and cyanosis.[19]

This study did not use any video laryngoscope to facilitate NGT insertion which is in contrast to a study done by Appukutty and Shroff[3] where video laryngoscope was used and found to be a superior technique. This device if used may even be useful to determine if there is any complication.

Several methods of insertion have been described with varying degree of success. A common technique in everyday practice involves blind nasal insertion of NGT with some external laryngeal manipulation or sometimes under direct vision, using a laryngoscope followed by instrumentation with Magill's forceps. The NGT have been inserted with reliable and high success rate (94.3% and 98.1% in first and second attempts, respectively) with the assistance of an intubation stylet tied together at the tips by a slipknot.[1]

The combination of different methods has also been reported in the literature. Outward and rightward pull of cricoid cartilage while maintaining mild flexion of the patient's neck, has been evaluated to be an easy and helpful method for unconscious intubated patients.[10] A study has evaluated the combined facilitating effect of reverse Sellick's maneuver and neck flexion. An esophageal guide wire-assisted insertion while maintaining manual forward laryngeal displacement has been compared with the technique of head flexion while maintaining lateral neck pressure.[11] Here, the combined facilitating effect of guide wire-assisted insertion and reverse Sellick's maneuver might have contributed to the highest success rate (99.2%) with that technique.

Limitation

We could not incorporate the obese, obstetric, pediatric, and emergency patients with a full stomach in this study. In the future, larger studies involving those populations may consolidate the suitability of these modified techniques and may establish the superiority of any one technique in those difficult or special situations.

CONCLUSION

This study indicates that reverse Sellick's maneuver to insert NGT is a better alternative to the conventional method of NGT insertion. This study has to be done in those obese, obstetric, pediatric, and emergency patients also to really establish a superiority of one procedure with other modified procedure.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.