In this episode I’ll:
1. Discuss an article comparing two lidocaine administration techniques.
2. Answer the drug information question “Can vasopressors be given via the intraosseous route?”
3. Share a tip for responding to inpatient medical emergencies.
Lead author: Bhakti K.Patel
Published in the journal CHEST October 2018
Lidocaine is frequently used in hospitalized patients via subcutaneous injection to reduce pain from various bedside procedures. Unfortunately, pain is temporarily increased from the injection before the lidocaine can work. The authors of this study investigated whether lidocaine dripped onto the skin prior to injection would reduce pain perception from the procedure.
The study was a randomized clinical trial of patients referred to a single hospital’s procedure service over a 4 year period. All patients received 1% subcutaneous lidocaine injection. Patients randomized to the intervention group had approximately 1 to 2 ml of lidocaine squirted onto the skin surface prior to subcutaneous lidocaine injection. Patients were blinded to the details of the intervention. In addition, the investigator who surveyed the patients to determine efficacy was also blinded.
Nearly 500 patients were randomized to treatment. There was a statistically significant improvement in the primary outcome of procedural pain with the intervention group. Visual analog pain scores were decreased by 25% compared to the control group from 16.6 to 12.2. A subgroup analysis revealed that pain scores were primarily improved for peripherally inserted central catheters.
The authors concluded:
Bedside procedures are exceedingly common. Data regarding the severity of procedural pain and strategies to mitigate it are important for the informed consent process and patient satisfaction. Overall, pain reported from common bedside procedures is low, but pain can be further reduced with the addition of lidocaine onto the skin surface to modulate pain perception.
Because the lidocaine squirted on the skin was water soluble, it is unlikely that it had a direct anesthetic effect. Instead, the authors suggest that the difference in temperature between the lidocaine solution and the patient’s skin is responsible for the analgesic effect. Under this theory, the room temperature lidocaine solution generates sensory nerve traffic within the spinal cord dorsal horn that can “gate” or inhibit the noxious signal from the lidocaine injection. If this theory is correct then the injection of lidocaine should occur immediately after the lidocaine is dripped onto the patient’s skin.
Drug information question
Q: Can vasopressors be given via the intraosseous route?
Any medication that can be given intravenously theoretically can be given via IO access. A review article in the journal Critical Care notes that a variety of medications have been successfully given via the intraosseous route including sedatives, vasopressors, anticoagulants, insulin, paralytics, and antiarrhythmics.
Tip for responding to inpatient medical emergencies
When giving adenosine for the treatment of supraventricular tachycardia, its effects depend on what the underlying rhythm is. If the underlying rhythm was caused by a re-entry phenomenon, adenosine will terminate the abnormal rhythm. But if the underlying rhythm was not due to re-entry, adenosine will instead temporarily slow or change the rhythm. For example, sinus tachycardia will gradually slow while atrial tachycardia will turn into AV block. If the underlying rhythm was atrial fibrillation then the rhythm will temporarily slow down but remain irregular. For more on treating SVT, and for specific guidance on learning how to read the EKG from a pharmacist’s point of view check out the training videos in my Hospital Pharmacy Academy. You can sign up at pharmacyjoe.com/academy.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.