Effect of Red Nail Polish on Pulse Oximetry Reading

Background: Pulse oximetry is a beat-to-beat, non-invasive and virtually risk-free method of assessing continuous arterial hemoglobin saturation. It is now a standard for monitoring care in the operating room and the post-anesthesia care unit. It is also widely used in the critical care setting. Numerous factors including dark skin, pigmentation, henna dye, nail polish etc. could lead to inaccuracy or ambiguous information about oxygen saturation. In many cultures, women decorate their fingernails with different colors of nail polish. Objectives: The purpose of this study was to determine the effect of red nail polish on the measurement of oxygen saturation. Materials and Methods: One hundred young women were recruited for this study and red nail polish was used to color the index finger of the non-dominant hand; the middle finger of the same hand was the control. Blood oxygen saturation was simultaneously measured by two calibrated pulse oximeters with two minutes interval for 30 minutes. Results: Red nail polish did not affect pulse oximetry measurement of oxygen saturation. There was no statistically significant difference between the control and the red nail polished fingers. Conclusion: Application of red nail polish does not cause statistically significant error in the measurement of oxygen saturation in young healthy individuals. KYAMC Journal Vol. 11, No.-4, January 2021, Page 181-183

Intubation following high-dose rocuronium in a cat with protracted laryngospasm

Case summary An 11-year-old spayed female domestic shorthair cat with a history of laryngospasm at induction of general anesthesia presented for dental evaluation and treatment. The cat was premedicated with hydromorphone (0.05 mg/kg) and alfaxalone (0.5 mg/kg) intravenously, pre-oxygenated for 5 mins (3 l/min, face mask) and anesthesia was induced with alfaxalone (to effect) intravenously. Lidocaine (0.1 ml, 2%) was applied topically to the arytenoid cartilages following loss of jaw tone. Laryngospasm was not noted during or immediately following lidocaine application. However, after waiting 60 s for the onset of effect of the topical lidocaine, laryngospasm was apparent. Orotracheal intubation by direct visualization was unsuccessful after four attempts by three anesthetists (with increasing levels of experience). At this point, a failed intubation was declared and the non-depolarising neuromuscular blocking agent rocuronium (1 mg/kg IV) given, resulting in arytenoid abduction and appropriate conditions for intubation. Successful intubation occurred 9 mins after induction of anesthesia. Oxygen was continuously supplemented throughout and arterial hemoglobin saturation with oxygen was never <94%. Relevance and novel information To the authors’ knowledge, this is the first report of the use of high-dose rocuronium to successfully resolve prolonged laryngospasm at induction of general anesthesia in a cat. Despite laryngospasm and a delay in achieving orotracheal intubation, low values for arterial hemoglobin saturation with oxygen (indicative of hypoxemia) were not observed, highlighting the benefits of pre-oxygenation and apneic oxygenation. The principles of the Difficult Airway Society 2015 guidelines were followed in managing this difficult intubation.