Israel Medical Association Journal

Background: The use of oral midazolam as premedication to induce anxiolysis before surgical procedures under local anesthesia is widely accepted in plastic surgery. Rhinoplasty performed under local anesthesia is known to generate high levels of perioperative anxiety, thus the use of appropriate premedication is important. Oral midazolam has been shown to be safe in various procedures. However, the safety of oral midazolam before rhinoplasty has not been evaluated.

Objectives: To evaluate the safety of premedication with oral midazolam prior to rhinoplasty by analyzing the intraoperative blood oxygen saturation levels as predictors of adverse respiratory events.

Methods: We retrospectively reviewed the anesthesia records of 62 patients who underwent rhinoplasty under local anesthesia and received premedication with oral midazolam for anxiolysis between March 2017 and December 2017. The median age of the patients was 25.4 years, and they were all classified as American Society of Anesthesiologists class 1. The patients received 10 mg midazolam hydrochloride orally 1 hour prior to the procedure. Oxygen blood saturation was monitored using a pulse oximeter and recorded every 15 minutes.

Results: All the patients maintained blood oxygen saturation levels above 95% (median peripheral capillary oxygen saturation 99%) on room air, and they did not require supplemental intraoperative oxygen. There were no transient hypoxemic events during and following the procedure.

Conclusions: Our study confirmed the safety of oral midazolam premedication to reduce perioperative anxiety when performing rhinoplasty under local anesthesia.

Background: Accurate pulse oximetry reading at hospital admission is of utmost importance, mainly for patients presenting with hypoxemia. Nevertheless, there is no accepted or evidence-based protocol for such structured measuring.

Objectives: To devise and assess a structured protocol intended to increase the accuracy of pulse oximetry measurement at hospital admission.

Methods: The authors performed a prospective comparison of protocol-based pulse-oximetry measurement with non-protocol based readings in consecutive patients at hospital admission. They also calculated the relative percentage of improvement for each patient (before and after protocol implementation) as a fraction of the change in peripheral capillary oxygen saturation (SpO₂) from 100%.

Results: A total of 460 patients were recruited during a 6 month period. Implementation of a structured measurement protocol significantly changed saturation values. The SpO₂ values of 24.7% of all study participants increased after protocol implementation (ranging from 1% to 21% increase in SpO₂ values). Among hypoxemic patients (initial SpO₂ < 90%), protocol implementation had a greater impact on final SpO₂ measurements, increasing their median SpO₂ readings by 4% (3–8% interquartile range; P < 0.05). Among this study population, 50% of the cohort improved by 17% of their overall potential and 25% improved by 50% of their overall improvement potential. As for patients presenting with hypoxemia, the median improvement was 31% of their overall SpO₂ potential.

Conclusions: Structured, protocol based pulse-oximetry may improve measurement accuracy and reliability. The authors suggest that implementation of such protocols may improve the management of hypoxemic patients.

Objectives: To suggest a simple outpatient technique for evaluating the response of arterial oxygen saturation to exercise for use as a marker of disease severity.

Patients and methods: Ninety-six patients with various degrees of COPD¹ were divided into three groups: mild (forced expiratory volume in 1 sec >65%), moderate (FEV1² between 50 and 65%), and severe (FEV1 <50%). Using continuous oximeter recording we measured oxygen saturation during 15 steps of climbing, and quantified  oxygen desaturation by measuring the “desaturation area”, defined as the area under the curve of oxygen saturation from the beginning of exercise through the lowest desaturarion point and until after recovery to the baseline level of oxygen percent saturation. Desaturation was correlated to spirometry, lung gas volumes, blood gas analysis, and 6 min walking distance.

Results A good correlation was found between severity of COPD and baseline SaO2³, lowest SaO2, recovery time, and desaturation area.  A negative correlation was found between desaturation area and FEV1 (r=-0.65), FEV1/forced vital capacity (r=-0.58), residual volume to total lung capacity (r=0.52), and diffusing lung capacity for carbon monoxide (r=-0.52). In stepwise multiple regression analysis only FEV1 correlated significantly to desaturation area.  A good correlation was noted between 6 min walking distance and desaturation area with the 15 steps technique (r=0.56).

Conclusions: In patients with severe COPD, arterial hypoxemia during exercise can be assessed by simple 15 steps oximetry. This method can serve both as a marker for disease severity and to determine the need for oxygen supplementation.

_____________________________________ 

COPD = chronic obstructive pulmonary disease

FEV1 = forced expiratory volume in 1 sec

SaO2 = arterial oxygen saturation