Hi guys, I am back. Sorry that I have been MIA for a while. I have started a new job at an academic center recently and been sick since the holiday with H3N2 flu, followed by the stomach flu and food poisoning. I finally feel that I am back to normal. I have been sick for almost a month and it made me truly appreciate the importance of health. I hope you all are well with the new year of 2018.
Recently one of my colleagues I have worked with told me that the use of intra-cuff lidocaine combined with the topical lidocaine over the glottis can significantly reduce the coughing upon emergence and she swore by it. So it piqued my interest and I did some research on this technique. First of all, it seems that high concentration of lidocaine (200-500mg in the cuff) is needed to be able to allow enough amount to pass the tracheal cuff. The ET cuff is made of polyurethane. Hence, alkalized lidocaine diffuse quicker through the cuff based on our chemistry 101. The study by Estebe et al. demonstrated that plasma lidocaine levels increased when 40mg lidocaine was alkalized (62.5 +/- 34.0 ng/mL) compared to 3.2 +/- 1.0 ng/mL for non-alkalized lidocaine at the end of 2 hours. This finding supported D’Aragon’s study that intra-cuff with alkalized lidocaine may not work due to its low concentration in plasma as his study did not find the reduction of the occurrence of coughing with the use of lidocaine in the cuff for surgeries less than 2 hours. Similarly, Bousselmi found the alkalized lidocaine in the endo-tracheal cuff did not alleviate coughing upon emergence for surgeries lasting less than 2 hours. However, Fagan and a few other groups have reported beneficial effects with the lidocaine used in the cuff. Why do we see the mixed results? There are several factors including concentration of the lidocaine, alkalized vs. non-alkalized lidocaine, duration of the surgeries, which may contribute to the conflicting results on reducing the coughing at the emergence. Some studies have used 2% lidocaine vs. 4% lidocaine . Some RCA studies looked at the surgeries that were longer than 2 hours with the lidocaine in the intra-cuff.
Why did I spend so much time to investigate the effects of lidocaine in the intra-cuff on reducing coughing? First of all, we shouldn’t take other people’s word for it. Just because someone told you so, it doesn’t mean it is accurate. Secondly, when we read research papers, we should pay attention to the variables in the studies such as the concentration of the drug, duration of the study etc, which can significantly affect the outcomes of the studies.
So to sum up, intra-cuff alkalized lidocaine could be another alternative to alleviate coughing with if the surgery is longer than 2 hours to allow enough lidocaine to pass through the cuff. If the surgery is short than 2 hours, lidocaine spray over the glottis will be effective in decreasing coughing and sore throat.
Thank you for reading and Happy Valentines!
Estebe JP1, Dollo G, Le Corre P, Le Naoures A, Chevanne F, Le Verge R, Ecoffey C. Alkalinization of intracuff lidocaine improves endotracheal tube-induced emergence phenomena. Anesth Analg. 2002 Jan;94(1):227-30
Bousselmi R, Lebbi MA, Bargaoui A, Ben Romdhane M, Messaoudi A, Ben Gabsia A, Ferjani M. Lidocaine reduces endotracheal tube associated side effects when instilled over the glottis but not when used to inflate the cuff: A double blind, placebo-controlled, randomized trial. Tunis Med. 2014 Jan;92(1):29-33.