Abstract

INTRODUCTION

Pulse oximetry is the standard monitoring technique of functional oxygen saturation (SpOtwo). As the use of fingernail polish has been described to alter SpO2 readings, its removal is usually recommended prior to measurement. Gel-based manicures take gained popularity in contempo years due to their attractiveness and longevity. However, the removal of gel boom polish requires a specialised process. Valuable fourth dimension and resources can exist saved if removal tin can be avoided. To our knowledge, there are no available studies on the event of gel-based manicures on pulse oximetry readings. Hence, we evaluated the effect with two oximeters, using unlike technology and wavelength combinations.

METHODS

17 healthy female adult volunteers were recruited for this single-blind randomised controlled trial. Subjects with hypothermia, hypotension, poor plethysmographic waveform and nail pathology were excluded. Colours tested were: blackness, purple, navy blue, dark-green, light bluish, white, xanthous, orange, pink and red. Pulse oximetry was measured at 15- and 30-second intervals using two different pulse oximeters, the Philips M1191BL and Masimo SET®. Means were compared using paired t-tests.

RESULTS

Using the Masimo oximeter, light bluish (ΔM = 0.97% ± 0.96%; p = 0.001) and orange (ΔM = 0.76 ± 1.17%; p = 0.016) gel boom polish resulted in a statistically significant increase from baseline SpO2 readings. With the Philips oximeter, the limits of understanding ranged from 2% for pink to 17% for black, indicating imprecision.

Decision

Gel-based manicures can result in overestimations of actual readings, delaying detection of hypoxaemia. Gel nail smooth should exist routinely removed or an alternative monitoring technique sought.

 Keywords: gel manicure, smash polish, oxygen saturation, pulse oximetry, SpO2

INTRODUCTION

Pulse oximetry is a simple, continuous, non-invasive and reliable monitoring device in routine medical practice that measures functional oxygen saturation (SpOii) in arterial blood. This inexpensive method too provides heart rate measurements and an indication of tissue perfusion based on pulse amplitude. Still, multiple factors tin affect the SpO2 reading. Endogenous factors such as low perfusion (secondary to hypothermia, low cardiac output, increased systemic vascular resistance, profound anaemia, etc) and dyshaemoglobinaemia (e.thousand. carboxyhaemoglobinaemia and methaemoglobinaemia) can compromise SpOtwo readings.(1,two) Exogenous factors such every bit excessive ambient lite or motion, intravenous dyes and nail polish may besides crusade artefactual readings.(2)

As the use of fingernail polish has been described to alter the SpO2 reading in normal subjects, removal of the polish is commonly recommended prior to measurement. Gel-based manicures have gained popularity in contempo years due to their bewitchery and resistance to chipping, scratching and denting (Fig. 1).(3) Gel smash polish is a type of acrylic-based nail polish equanimous of a mixture of acrylate monomers that require ultraviolet light for polymerisation and hardening.(3) Nonetheless, removing gel nail smooth is difficult and requires a specialised procedure. In addition, patients are often resistant to removal, especially of elaborate, costly designs. Equally clinicians increasingly run across such patients in emergency and operative situations, the question arises of whether gel-based manicures interfere with measurements.

Fig. ane

Photo of a volunteer's fingernails (assigned number: v) shows gel-based manicure of ten different colours.

To our knowledge, no studies on gel-based manicure take been conducted. In addition, the literature has shown conflicting results regarding regular(iv-7) and acrylic(one) blast smooth. Studies by Coté et al(4) described the effects of black, blue and green fingernail polish to significantly lower SpOii readings by three%–half dozen%, postulating that information technology could be due to the differing spectrophotometric absorption abilities of the colours. Similarly, Rubin(v) discovered that a particular blue fingernail smoothen with similar spectrophotometric data resulted in a decrease in SpOtwo, from 97% to 87%. Contrastingly, studies by Hinkelbein et al(6) and Yamamoto et al(seven) did non find whatsoever departure in hypoxic subjects. Valuable time, resource and coin can exist saved if removal can be avoided. Hence, nosotros evaluated the furnishings of the gel-based manicure on pulse oximetry readings with two mutual oximeters, using different engineering science and wavelength combinations.

METHODS

This was a randomised single-blind self-controlled report of healthy subjects, conducted at Singapore General Hospital, Singapore. The written report was reviewed and approved past an independent ethics committee (CIRB ref no. 2016/2382) and adheres to the applicative EQUATOR CONSORT guidelines.(8)

Nosotros recruited 17 healthy female developed volunteers in October 2016 after obtaining written informed consent. Male participants were considered for this study simply were not included due to the lack of male person volunteers. All subjects were aged 21–xl years, of American Society of Anesthesiologists Class 1 and of Asian descent. Subjects with a history of anaemia or haemoglobinopathy, or who were found to take hypothermia (T < 34°C), systolic blood pressure < 90 mmHg and/or diastolic blood pressure < 50 mmHg, poor plethysmographic waveform or any nail pathology were excluded. A normal plethysmographic waveform was defined visually as consisting of equally spaced, every bit wide waves of equal amplitude over 10 seconds, while a poor waveform consisted of an inconsistent or irregular pattern of varying amplitude and/or wavelength. A baseline SpO2 reading on each finger was taken at 30 seconds.

Each bailiwick was assigned a number from i to 10 by simple randomisation using an online number generator.(9) 10 nail polish colours were pre-selected and numbered from i to ten in the following lodge: (1) black; (two) purple; (three) navy blueish; (4) dark-green; (v) light blue; (half-dozen) white; (7) yellow; (8) orangish; (9) pink; and (10) red. The fingernails of our subjects were painted from the left to the correct mitt, showtime with the left little finger to the left pollex (i.eastward. left little finger, band finger, middle finger and index thumb) and continuing from the right thumb to right niggling finger (i.east. right thumb, index finger, middle finger, ring finger and petty finger). The aforementioned color sequence would commence from the finger corresponding to the randomly allocated number, starting the count from the left pinkie (Fig. 1).

Pulse oximetry measurements were fabricated with ii pulse oximeters: the Philips M1191BL adult finger sleeve sensor (Philips Medizin Systeme Böblingen GmbH, Böblingen, Frg) and the Masimo SET® Wrap-around-Style Sensor (Masimo Corporation, Irvine, CA, Us), connected to the Masimo Root® monitor. The Philips reusable sensor probe emits light at wavelengths of 660 nm and 940 nm, while the Masimo RD Set™ Wrap-around-Style Sensor device emits light at 660 nm and 905 nm. These two models were selected as they were (a) commonly used in our clinical setting; and (b) would illustrate the effects of dissimilar wavelength and technology combinations.

Due to the variety of gels available, it was impractical to test the limerick of all variations. In this trial, Gellyfit (Sizuka Korea Co Ltd, Seoul, Korea), a gel nail shine, was used. A nail technician coated each smash with four layers of nail smooth: a base coat, two layers of gel nail polish and a tiptop coat. LED (light-emitting diode) light was used to cure the nail polish between applications.

All SpOii recordings were taken in room air with the subjects sitting in the aforementioned place to minimise inaccuracies caused by movement artefacts or ambient light. SpO2 recordings were taken before and after nail smooth application so that the patient's unpainted finger could exist taken as its ain control. This was done because previous studies had elicited variations in perfusion rates betwixt the fingers of each individual, resulting in varying SpOtwo readings. Results were recorded by a blinded observer who was unaware of which subject area was beingness studied and what nail shine color, if whatsoever, had been applied.

The pulse oximetry probe was placed direct on the boom bed. Measurements of each finger were recorded after stable readings were obtained, at predetermined intervals of xv and 30 seconds. The fourth dimension interval for SpO2 recording was adamant based on signal averaging time, which was set at x seconds for both devices, and fourth dimension efficiency in conducting the study. Data dropout was defined every bit instances where a poor pulsatile SpO2 waveform was seen after two minutes of repositioning and transmission stabilisation of the SpO2 probe, based on a notation made by the contained observer.

For the Philips oximeter, no reading could be obtained in six instances, for ane blackness, 2 purple and 3 pink nails, and these were treated as missing values in the data assay. For the Masimo oximeter, a poor waveform was nowadays in 14 readings at the 15-second interval, with an accompanying SpOii reading. In these instances, the values obtained were included in the analysis.

Sample size was derived on a basis of a paired t-examination. To achieve a power of 0.80, a Blazon 1 error rate of 5%, an effect size of 0.70 and a standard divergence of i% in the difference betwixt pre- and post-awarding SpOii readings, a minimum of 16 volunteers were needed. Results were not stratified co-ordinate to age, every bit previous studies accept shown that age does not bear upon SpO2 readings. Dropout values were replaced using a single imputation method of mean exchange, where missing values were replaced with the hateful value obtained from all readings of that finger using a unmarried imputation of missing values.(ten) Statistical analysis was performed using paired independent t-test. A p-value < 0.05 was considered statistically pregnant. Standard deviation was used to assess variability in SpOii readings. Precision of SpO2 readings was analysed using the Bland-Altman method of comparison on the 95% limits of agreement, which were estimated by calculating the mean difference ± one.96 standard deviation of the differences.(11) F-ratio examination was used to compare the standard deviation of mean readings, using a statistical significance level of 0.05. Statistical analysis was performed with IBM SPSS Statistics for Windows version 23.0 (IBM Corp, Armonk, NY, USA).

RESULTS

The mean systolic claret pressure was 111 (range 95–128) mmHg and mean diastolic blood pressure was 70 (range 54–88) mmHg. The hateful tympanic temperature was 36.5°C (range 35.8°C–37.i°C). The effects of calorie-free blue (∆M = 0.97% ± 0.96% [range −1.93% to −0.01%]; p = 0.001) and orange (∆M = 0.76% ± 1.17% [range −1.93% to 0.41%]; p = 0.016) gel-based nail smooth on Masimo pulse oximeters revealed a statistically significant increase in baseline pulse oximeter readings. White (∆M = 0.06% ± two.57% [range −2.51% to 2.63%]; p = 0.93) had the smallest event of all the colours used (Table I).

Table I

Functional oxygen saturation readings of gel-based manicure colours compared with controls (due north = 17).

Although the Philips pulse oximeter did not produce statistically significant findings, a few of the results were clinically relevant. Blackness (ΔP = −1.26% ± 4.58% [range −three.32% to 5.84%]; p = 0.27) and orange (∆P = −0.44% ± 2.l% [range −2.06% to 2.94%]; p = 0.48) gel-based manicure had a mean bias of more than ± 2%. Light blue (∆P = 0.06% ± 0.88% [range 0.82% to 0.94%]; p = 0.79) had the smallest issue of all the colours used (Tabular array I). With the Philips oximeter, the limits of understanding ranged from 2% for pink nail smoothen, indicating a small variation in all readings, to 17% for black boom shine, indicating a greater variation in SpOtwo readings. The limits of agreement ranged from 3% for light blueish nail smoothen to 9% for blackness smash polish using the Masimo oximeter.

When the F-examination was used to compare the standard deviation of readings as a measure of precision, the colours black (F = 3.9), purple (F = 4.0), navy blueish (F = 6.four), light blueish (F = 4.vi) and white (F = 7.0) were to a higher place the critical F-value, indicating a wider range of readings on the Masimo device after application of nail polish. Comparatively, the colours black (F = 25.v), purple (F = 123.0), green (F = 2.8), white (F = two.5), yellow (F = 11.6), orange (F = viii.7) and pink (F = 3.6) showed comparatively poorer precision on the Philips device later on application of smash polish. Notably, a wider range of F-ratio, and therefore a larger variance, was seen on the Philips oximeter (F = one.six–123.0) than the Masimo oximeter (F = 1.0–7.0). In improver, black (F = 25.5) and majestic (F = 123.0) affected the precision of the readings on the Philips device much more than the other colours.

Word

To the best of our knowledge, our study is the first to evaluate the accuracy and precision of pulse oximetry on gel-based manicure. Nosotros found that blackness blast smooth resulted in poorer precision in SpO2 readings for both the Philips and Masimo models (Figs. 2a & b). This was consistent with the existing literature.(four-7) Still, it was also noted that orangish and low-cal blueish gel nails resulted in a statistically pregnant increase in SpO2 readings on the Masimo device, findings that were vastly different from those in the literature. Yamamoto et al(seven) postulated that due to their specific light-absorption characteristics, various smoothen preparations and colours do not correlate with human eye colour perception; the hypothesis was further confirmed by spectrophotometric studies performed past Rodden et al.(12) As colour perceived by the human being middle is due to the summation of diverse absorption values within the visible range of light,(13) it does not correlate with lite assimilation at the wavelengths emitted by sensor probes, and hence may account for our findings.

Fig. 2

Box-whisker plots show functional oxygen saturation findings using (a) the Masimo SET® and (b) the Philips M1191BL subsequently awarding of gel nail shine.

Moreover, our findings advise that boom shine could issue in an overestimation of bodily oxygen saturation. The chromatic characteristics of boom polish determine its light assimilation and scattering interactions, resulting in optical shunting of light around the finger periphery. The event may be more prominent in the Masimo model with its brighter LED lite.(thirteen) Furthermore, the event of optical shunting could be compounded past the different wavelengths of each sensor probe. Importantly, although our findings were statistically significant, they were non clinically pregnant (< 2%).

The Philips oximeter failed to detect readings ane.8% of the time (half-dozen out of 340 readings) as compared to the Masimo oximeter, which detected all readings. In add-on, the Philips device was associated with poorer precision in readings. This could be due to the differences between the Philips Fourier antiquity-suppression applied science (FAST) and the Masimo betoken extraction applied science (SET).(13) Prepare uses a discrete saturation transformer with a reference betoken generator, an adaptive filter and a meridian picker, which piece of work in concert to determine the virtually likely SpO2 value based on all incoming signals.(12) Conversely, the FAST algorithm identifies the frequency components of the pulse rate and compares those to the frequency components of the incoming point to select the component that is at pulse rate for both the red and infrared wavelengths, attenuating incoming signals that practice not occur synchronously with the pulse charge per unit.(thirteen) Hence, the differences in operation between the two pulse oximeters may exist a consequence of the Masimo Set being superior in separating the arterial signal from venous and other artefactual signals, such as gel nail polish, that may event in a poorer signal-to-racket ratio.

This study was not without limitations. Commencement, our study only involved healthy subjects, who may not exist representative of a patient population with pregnant cardiac or respiratory affliction, and lower baseline SpO2. Hypoxic conditions(fourteen) may result in further reductions in accuracy and precision. Without hypoxic subjects, the furnishings of desaturation on pulse oximetry readings were not investigated. Further studies on hypoxic subjects may be enlightening, as an overestimation of actual oxygen saturation could issue in a delay, or fifty-fifty failure, in the detection of hypoxaemia, leading to a disastrous patient outcome. Second, co-oximetry was not used equally a measure of accuracy, as it entailed taking arterial claret gas. Spectral analysis of each color was as well not quantified with spectrophotometry. Third, unmarried imputation methods were used for SpOtwo dropout values, which could exist related to the colour of the nails, perchance reducing the variability of our results. Lastly, unlike brands and thickness of gel smash polish may produce slightly unlike results. We mitigated this trouble by using a ordinarily used brand of gel blast smoothen that contains similar compounds with most other brands. The aforementioned brand of nail polish was used for all colours in the written report. Furthermore, standardising both the boom technician and the number of layers practical minimised whatever differences in the thickness of the gel smash polish.

In conclusion, unlike colours of nail polish can cause a statistically significant change in pulse oximeter readings in healthy volunteers, although our findings were not clinically significant. We did not investigate the furnishings of gel nail polish on hypoxic patients. It can besides cause overestimations of actual SpOtwo readings, which could delay or even fail in the detection of hypoxaemia. In clinical, surgical and emergency settings, gel blast smooth should either be routinely removed or an alternative monitoring technique sought.
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