Surgery size: Small (thoracoscopy) Medium (thoracotomy <3h) Large (thoractomy >3h or blood loss >1000mL)
Premedicated with oral midazolam (up to 7.5 mg) Randomized: Licorice extract Sugar solution Gargle for at least one minute sitting Induction five minutes post gargling (fentanyl, propofol, rocuronium) Intubation following loss of TOF with DL ETT (*unlubricated) with cuff pressures of 20 mmHg Intra-operative analgesia with narcotics/paracetamol and a intercostal plexus block at the end of surgery Extubated “while still anesthetized” Post-operative analgesia with piritramide (synthetic opioid slightly weaker than morphine)
Measurements were taken at 30 minutes, 90 minutes after arrival in PACU and 4 hours post extubation 11 point Likert scale (0 – 10) Also assessed pain on swallowing at 30 minutes. Any score >0 defined as a sore throat. Coughing assessed by observation and questioning the patient at 0, 30, 90 minutes post extubation. None = 1 Mild = 2 Moderate = 3 (similar to common cold) Severe = 4 Above measures repeated on first morning post-op.
Efficacy Futility Harm
Primary outcome: Effect of licorice gargle on occurrence of sore throat at rest after intubation with DL ETT compared with sugar- water through the first four postextubation hours. Secondary outcomes: Effect of licorice on sore throat on postoperative day 1 Incidence of sore throat during swallowing assessed at 0.5 hours post PACU arrival Incidence of coughing over 5 time measurements Amount of coughing over 5 time measurements
Measurements Results Statistical black box of number crunching
Overall RR = 0.46 ( )
Seems to be okay – particularly for the primary outcome. Do I care particularly about coughing end points? Decreased coughing would likely be decreased pain in the post-thoractomy patient.
Primary assess effect of licorice gargle on sore throat at rest after intubation with DL ETT compared with sugar water at 0.5, 1.5, 4 hours. Secondary Sore throat at rest POD 1 Incidence of sore throat during swallowing at 0.5 hours Overall difference in pain scores between at rest and swallowing at 0.5 hours and across four time points. Incidence of coughing and amount/severity of coughing
Pain vs. No pain Objective outcome Amount of pain (0-10) More subjective, but validated scale Incidence of coughing Objective Amount of coughing Very subjective. ? Validated (was published previously)
“Web-based” system used just prior to procedure. Don’t state what system in particular was used…
>0.2 standardized difference would indicate imbalance
Randomization with computerized system by “independent researcher” not involved in subsequent data collection Licorice/sugar preparations by “independent apothecary” Independent researcher not involved in data collection used to supervise gargling Patients not told which solution they were using Though likely could taste Were only told they would be trying two different “sweet” solutions
Assessments in PACU were done by nurses “not present” for gargling Possible patient’s could mention what flavor they had when gargling…. Post-operative assessment on day 1 done by “independent and blinded investigator” Again, possible that patient could mention/tell investigator what they had tasted
One patient in each arm was lost to follow-up Both remained intubated post surgery Licorice group Results were entered as “worst case scenario” i.e. sore throat at all time points, coughing at all time points Sugar group Results entered as “best case scenario” i.e. no sore throat at any time point and no coughing at any time point Also one patient withdrawn secondary to emergency surgery
DL ETT vs. Single lumen ETT Incidence with DL ETT likely higher Would relative risk/treatment effect be as pronounced with single lumen tubes? Previous study was with single lumen tubes Thoracic/Thoracotomy patients No documentation of comparability of opioids administered during cases. Hopefully similar between groups No documentation regarding airway grading/difficulty Use of dexamethasone?
Why bother with the safety analysis? Given the low pain scores in their study, how important a complication is it?
Two studies now showing nearly identical results 2 fold decrease in incidence of post-operative sore throat Statistically significant results Should this change my practice? How much do I care about POST Incidence seems relatively high But how bad is it (very low pain scores in this study) Is there any monetary cost (work days lost, prolonged hospital stay etc.) associated with POST Doesn’t appear to be any harm, likely very inexpensive, potential benefit... What about LMA’s?