Topical lignocaine anaesthesia for oropharyngeal sampling for COVID-19

Abstract

Objectives To ascertain if topical lignocaine application in oropharynx prior to swab sampling to test for COVID-19 improves a patient's comfort and to assess its effect on the swab sample taken to conduct the RT-PCR. Methods Adult patients testing positive on the RT-PCR COVID-19 test were sampled again within 48 h after administering topical oropharyngeal anaesthesia. Patients were asked to rate their discomfort on a visual analog scale (VAS) for both sample A and B. A qualitative real-time RT-PCR for detection of SARS-CoV-2 RNA, was performed, and the cycle threshold value (Ct), used as a surrogate marker for the viral load, was measured for the sample taken without lignocaine (sample A) and the sample taken post-lignocaine application (sample B). The difference in Ct values of both the groups was checked for any statistical significance using paired t-test. Wilcoxon signed rank test was used on VAS scores to determine any significant decrease in discomfort. Results Forty patients were included in the study. Twenty-nine patients (72.5%) reported the procedure to be more comfortable post-lignocaine application. Median (IQR) discomfort on VAS decreased from 7 (1) to 5 (2) after lignocaine use, which was statistically significant (p < 0.05). Mean Ct value for sample A was 17.21 ± 5.25 and for sample B was 18.44 ± 4.8 (p > 0.05), indicating a non-significant effect of lignocaine on SARS-CoV-2 concentration in the sample. Conclusion Topical lignocaine, while improving the comfort of the procedure of oropharyngeal sampling for patient did not alter the SARS-CoV-2 viral load that was detected in nasal and oropharyngeal samples taken together.

Less Exposure for Health Care Workers, More Comfort for Patients During COVID-19 Swab Testing

“…Although the lidocaine used in that study was of a higher dose, had a different form, and applied for different indications, the results are consistent with those of the current study. In a study by Kanodia et al (2021), patients were instructed to suck lozenges containing 200 mg of lidocaine for 3 to 4 minutes before undergoing sampling for the PCR test. The dose of lidocaine used in that study was 10 times higher than that used in the current study.…”

Opportunistic COVID‐19 vaccination in the emergency department

“…Very few eligible patients have declined vaccination which supports evidence from American EDs. 4 Instead, our patients cite numerous barriers to vaccination; 40% of Australians are functionally illiterate 5 and many describe significant competing daily priorities such as finding shelter for the night or navigating an immediate threat of family violence. Furthermore, these patients are often without smartphones or the internet access required to negotiate online appointments.…”

“…2,3 Nasopharyngeal sampling is known to stimulate the gag and cough reflex which precipitates high intrathoracic pressures similar to vomiting. 4,5 Vomiting is an important cause of further ocular complications in a patient with an open globe. This is avoided by good prophylaxis with anti-emetics prior to further examination and surgical intervention in the operating theatre.…”

COVID‐19 swab in patients with suspected open globe

“…Topical oropharyngeal anaesthesia delivered either by spray or lozenge may contribute to patient comfort but may not completely prevent the gag and cough reflex. 5 Alternative methods such as saliva testing may be more acceptable but is not as widely available at present.…”

“…2,3 Nasopharyngeal sampling is known to stimulate the gag and cough reflex which precipitates high intrathoracic pressures similar to vomiting. 4,5 Vomiting is an important cause of further ocular complications in a patient with an open globe. This is avoided by good prophylaxis with anti-emetics prior to further examination and surgical intervention in the operating theatre.…”