This study was a single-blind randomized clinical trial and was registered with the government registry of clinical trials in Iran (http://www.IRCT.ir) under trial number IRCT20091012002582N18. A partial waiver for Health Insurance Portability and Accountability Act (HIPAA) was obtained to allow the investigative team to screen the patients’ charts for their eligibility. An informed consent was obtained from the patients if their cognition level was intact or from the next-of-kin/healthcare proxy if the mentation was suppressed. Five hundred and fifty-one patients who were admitted into two university affiliated ICUs and needed NGT placement were enrolled in this randomized clinical trial.
Study protocol
The study took place at the mixed medical/surgical ICUs of the two main teaching hospitals (1000 inpatient bed) and major trauma centers in Tabriz, Iran from April 2018 to Jan 2019. Flow diagram of the study is shown in Fig. 1. All critically ill patients older than 18 years of age and without skull base fracture, coagulopathy, nasopharynx and esophageal pathology, history of head and neck radiotherapy and neck trauma who needed NGT placement were enrolled in the study. Patients’ refusal to participate in the study was considered as the exclusion criteria. Patients were randomly divided into two groups using a balanced block randomization by the Research Pharmacy team; group NFLP in which NGT was inserted for all patients with standard method (NFLP) and group SORT in which NGT was inserted through SORT maneuver.
A Fr. 14, 105-cm NG tube was used in all cases, and the insertion was performed by two critical care registered nurses who were experienced in NG tube insertion in critically ill patients by these two methods.
As SORT method is a new one and not routine in our ICUs, the nurses who were supposed to perform it had to complete the education course for SORT method. Only two nurses performed the NGT insertion by SORT method in this study in order to decrease interpersonal variations. These two nurses were educated to perform NGT insertion with SORT maneuver for 30 days prior to the start of our trial. They performed almost 35 to 40 NGT insertion with SORT maneuver. We assessed the success/failure rate for them which did not have any difference between the two nurses.
The distal end of the NG tube was lubricated in all cases and passed through the larger nostril to the nasopharynx. The tube was then advanced into the posterior oropharynx according to the selected technique. In Group NFLP, 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 to the targeted point. In Group SORT, after the patient was placed in sniffing position, NGT was oriented from the nose to the esophagus entrance considering anatomical landmarks. The position of NGT tip was changed by back and forth and rotational movements until it found its way through the esophagus without any resistance. If any resistance occurred, the procedure was stopped. Sliding distal end of NGT on the posterior wall of oropharynx into the esophagus by the tip of the index finger is sometimes helpful for an accurate orientation. After that, we rotated the head to the contralateral side of NGT entrance. Then, the tip of NGT was directed deep into the esophagus by twisting movements to reduce resistance. We performed external pressure on the area of piriform sinus if the initial maneuver failed. We confirmed the correct place of NGT with epigastric auscultation, aspiration of gastric contents and finally a chest X-ray for reconfirmation. If the first attempt was failed, NGT was withdrawn and fully cleaned and then reinserted in the same nostril. After the third attempt, the technique was considered as “failed” and NGT insertion was guided by laryngoscope and Magill forceps to advance the NGT under direct vision. The NGT length was estimated with measuring the distance from the xiphoid process to the earlobe via the nose [14].
Primary endpoint of our study was success rate for NGT insertion in each group. The secondary end points were complication and ease of insertion in each group.
Data sampling and recording
Patient characteristics and following data were noted for all patients: success rate at the first attempt, the second attempt and overall for each group, time required for successful first attempt and overall successful insertion time, various complications including kinking, knotting and bleeding. We also reported other rare complications like insertion to cranium, pneumothorax and chylothorax if they occurred.
We evaluated the ease of insertion with a 4-grade score as following: first grade as successful insertion in less than 50 s and in the first attempt, second grade as successful insertion in the first attempt with more than 50 s or in the second attempt with less than 100 s, third grade as successful insertion in the 2nd attempt with more than 100 s or in three attempts, and fourth grade as failed insertion.
Sample size and statistical analyses
The sample size was calculated based on the pilot study as there was no similar previous study.
A sample size of 168 per group was calculated to identify at least a 10% difference in proportions of failure from the baseline 5% proportion and to fulfill a minimum statistical power of 90% and 95% confidence level. Additional sample size was considered for the multivariable analyses. Finally, 200 and 196 patients were assigned into the NFLP and SORT groups, respectively.
At the first stage, the distributions of quantitative variables were examined using the Kolmogorov–Smirnov test and histogram plots. The quantitative variables with and without normal distribution were reported as mean ± standard deviation and median (interquartile range), respectively. The qualitative variables were reported as frequency (%). Normally distributed variables were compared between two groups using independent samples t test and those without normal distribution were compared with Mann–Whitney U test. In addition, Chi-squared and Fisher’s exact tests were used to compare the qualitative variable between two groups. The study variables were compared between the NFLP and SORT groups and those with P < 0.1 were further studied whether to be included as confounding variables. Finally, binary and multinomial logistic regressions were applied to examine the association of categorical and binary outcomes with NGT insertion techniques, respectively, after adjusting for confounders. P < 0.05 was considered statistically significant. All analyses were done by SPSS software version 19 (SPSS Inc., Chicago, IL, USA) and Stata version 11 (Stata Corporation, College Station, TX, USA).