Handheld Pulse Oximeter Research Articles

Technical note: a nose ring sensor system to monitor dairy cow cardiovascular and respiratory metrics.

Monitoring cardiovascular and respiratory measurements corresponds to the precision livestock farming (PLF) objective to continuously monitor and assess dairy cows' welfare and health. Changes in heart rate, breathing rate, and oxygen saturation (SpO2) are valuable metrics in human and veterinary medicine to assess stress, pain, illness, and detect critical conditions. The common way to measure heart rate is either manually or with a stethoscope. Under research conditions, heart rate is usually measured with a sports watch chest belt. Breathing rate is obtained by counting the cow's flank movements which is a time-consuming and labor-intensive method that requires training and is prone to human error. No devices are available on the market that enable practical and easy pulse oximetry in farm animals. This study presents a wireless nose ring sensor system (NoRS) composed of thermal and photoplothysmography sensors that attach to the nostrils of four Holstein dairy cows. The NoRS's thermocouple measured the cow's nasal cavity air temperature; an optic sensor measured the IR (660 nm) and RED (660 nm) signals reflected from the cow's nasal septum. Breathing was calculated from the thermocouple signal's center frequency with a fast Fourier transformation or the signal peak count (i.e., oscillations). The breathing rate was compared to breathing observed by concurrently counting the flank movements. Heart rate and SpO2 were measured by integrated pulse oximetry and heart rate monitor module (MAX30101 TinyCircuit) assembled on the NoRS circuit. Heart rate was also measured with FFT and by counting the number of peaks from the optic sensor's raw IR and RED signals. These measures were compared to an off-the-shelf hand-held pulse oximeter's heart rate and SpO2 readings during the same time. The comparisons revealed highly significant correlations for the heart rate readings where the strength of the correlation was sensitive to the method. The correlation between breathing rate and the veterinarian's visual observations was low, albeit significant. Thus, inhale-exhale cycle counting constitutes a more precise approach than flank movement counts. The hand-held device's 96% SpO2 is compatible with near-saturation values expected in healthy cows. The mean NoRS SpO2 reading was 3% less. After further piloting under field conditions, the NoRS will require no animal restraining to automatically and continuously record cows' breathing rate, heart rate, and SpO2.

Performance of automated versus nurse-measured respiratory rate measurements in hospitalised malnourished children.

In resource limited settings accurate respiratory rate (RR) measurement directly informs medical decision-making for children with respiratory problems.1 Counting RR remains a challenge: it may not be done 2 or gives rise to highly disparate values despite the use of RR counters.3 Technological solutions may permit more children to have assessments and may alter clinical decisions. A hand-held pulse oximeter with integrated RR measurement (Rad-G, Masimo, Irvine California) in 97 children reported good agreement between measurements of the device and pediatricians.

Comparison of Various Methods of Detection of Hypoxemia and Correlation of Hypoxemia with Clinical Features among Pediatric Patients 3 Months to 5 Years Old with Community-Acquired Pneumonia at a Tertiary Hospital Emergency Room

Introduction: Pulse oximetry is frequently utilized as a rapid, non-invasive, point-of-care alternative to arterial blood gas analysis in measuring oxygen saturation of children with pneumonia. Objectives: To compare portable fingertip pulse oximetry saturation (SpO2PF), handheld pulse oximetry saturation (SpO2H) and arterial oxygen saturation (SaO2) in detection of hypoxemia, and correlate hypoxemia with clinical features in children with pneumonia. Methodology: This was a prospective, observational, cross-sectional study involving patients 3 months to 5 years old with pneumonia. Oxygen saturation was measured using a portable fingertip pulse oximeter, a handheld pulse oximeter, and arterial blood gas analysis. Results: Eighty-six children were included. SpO2 PF underestimated oxygen levels by 0.126% (95% CI -0.240 to 0.491), while SpO2H underestimated it by 0.323% (95% CI -0.075 to 0.721). Between portable and handheld readings, the mean difference was 0.198% (95% CI -0.089 to 0.484). Across the three methods, limits of agreement ranged from -3.388 to +4.035%. There was no statistically significant difference in variance among the three measurements. Children with tachypnea (cOR 2.623, 95% CI 1.06 – 6.48, p = 0.037), difficulty breathing (cOR 6.316, 95% CI 1.96 – 20.34, p = 0.002), and subcostal retractions (cOR 2.842, 95% CI 1.05 to 7.69, p = 0.040) were more likely to have hypoxemia. Conclusion: Pulse oximetry closely correlates with arterial blood gas analysis within acceptable limits of agreement and with no significant differences in variance among measurements. Difficulty breathing, tachypnea and subcostal retractions were significantly more likely to be observed in hypoxemic children.

Dark Adaptation at High Altitude: An Unexpected Pupillary Response to Chronic Hypoxia in Andean Highlanders.

Healy, Katherine, Alain B. Labrique, J. Jaime Miranda, Robert H. Gilman, David Danz, Victor G. Davila-Roman, Luis Huicho, Fabiola León-Velarde, and William Checkley. Dark adaptation at high altitude: an unexpected pupillary response to chronic hypoxia in Andean highlanders. High Alt Med Biol. 17:208-213, 2016.-Chronic mountain sickness is a maladaptive response to high altitude (>2500 m above sea level) and is characterized by excessive erythrocytosis and hypoxemia resulting from long-term hypobaric hypoxia. There is no known early predictor of chronic mountain sickness and the diagnosis is based on the presence of excessive erythrocytosis and clinical features. Impaired dark adaptation, or an inability to visually adjust from high- to low-light settings, occurs in response to mild hypoxia and may serve as an early predictor of hypoxemia and chronic mountain sickness. We aimed to evaluate the association between pupillary response assessed by dark adaptometry and daytime hypoxemia in resident Andean highlanders aged ≥35 years living in Puno, Peru. Oxyhemoglobin saturation (SpO2) was recorded using a handheld pulse oximeter. Dark adaptation was quantitatively assessed as the magnitude of pupillary contraction to light stimuli of varying intensities (-2.9 to 0.1 log-cd/m2) using a portable dark adaptometer. Individual- and stimulus-specific multilevel analyses were conducted using mixed-effect models to elicit the relationship between SpO2 and pupillary responsiveness. Among 93 participants, mean age was 54.9 ± 11.0 years, 48% were male, 44% were night blind, and mean SpO2 was 89.3% ± 3.4%. The magnitude of pupillary contraction was greater with lower SpO2 (p < 0.01), and this dose relationship remained significant in multiple variable analyses (p = 0.047). Pupillary responsiveness to light stimuli under dark-adapted conditions was exaggerated with hypoxemia and may serve as an early predictor of chronic mountain sickness. This unexpected association is potentially explained as an excessive and unregulated sympathetic response to hypoxemia at altitude.

Detection of Pulpal Blood Flow In Vivo with Pulse Oximetry in Dogs

The aim of the present study was to investigate the ability of pulse oximetry to detect blood flow within the canine tooth of dogs. Dogs aged 18-138 months presenting for oral treatment and meeting the inclusion criteria underwent pulse oximetry evaluation of at least one canine tooth. Oxygen saturation (SpO2) and pulse rate values were acquired from vital canine teeth of 38 clinical patients (representing 40 total teeth) with a handheld pulse oximeter and compared to a control area. SpO2 values from the tooth and control area were recorded every 5 s for three 60-s intervals. The sensors were repositioned after each 60-s interval. The vital teeth consistently recorded SpO2 values significantly lower than the control area. The mean vital tooth SpO2 was 85.9% (median = 87%; SD = 8.6), and the mean control area SpO2 was 97.7% (median = 98%; SD = 1.8). An age-related significant difference was noted in vital tooth SpO2 values. In conclusion, the present data support the possible use of pulse oximetry to detect blood flow in canine teeth. However, there was no significant correlation between SpO2 values in the vital tooth and in the control areas. Additionally, the results were not definitive, and validation of the modality with additional studies of non-vital canine teeth is needed before clinical use can be recommended.

Pulse oximetry screening and home birth

In the US, pulse oximetry screening for detection of critical congenital heart disease has become accepted as an important aspect of newborn screening. Systems to implement pulse oximetry screening are being developed and put in place across the country. In this issue of The Journal, Narayen et al evaluate an approach to pulse oximetry screening developed for the Netherlands, where home birth and very early discharge from the hospital after birth are much more common. To develop an appropriate system for home birth, the authors had to alter the timing of administration of pulse oximetry. They also had to train community midwives and provide each midwife with a handheld pulse oximeter. The results were encouraging in that such screening and follow-up appears feasible. Neonatal pathology other than critical congenital heart disease was detected and the number of false positive screens was low. However, it is important to emphasize that this approach only works with the development of a regional system to support it. These results would not support the use of pulse oximetry in individual home births without the appropriate healthcare system as supporting infrastructure.Article page 188▶ In the US, pulse oximetry screening for detection of critical congenital heart disease has become accepted as an important aspect of newborn screening. Systems to implement pulse oximetry screening are being developed and put in place across the country. In this issue of The Journal, Narayen et al evaluate an approach to pulse oximetry screening developed for the Netherlands, where home birth and very early discharge from the hospital after birth are much more common. To develop an appropriate system for home birth, the authors had to alter the timing of administration of pulse oximetry. They also had to train community midwives and provide each midwife with a handheld pulse oximeter. The results were encouraging in that such screening and follow-up appears feasible. Neonatal pathology other than critical congenital heart disease was detected and the number of false positive screens was low. However, it is important to emphasize that this approach only works with the development of a regional system to support it. These results would not support the use of pulse oximetry in individual home births without the appropriate healthcare system as supporting infrastructure. Article page 188▶ Pulse Oximetry Screening for Critical Congenital Heart Disease after Home Birth and Early DischargeThe Journal of PediatricsVol. 170PreviewTo assess the feasibility of pulse oximetry (PO) screening in settings with home births and very early discharge. We assessed this with an adapted protocol in The Netherlands. Full-Text PDF

Pulse Oximetry Overestimates Oxygen Saturation in COPD.

Measurement of oxygen saturation with a handheld pulse oximeter is widely practiced as a surrogate to invasive arterial blood gas analysis. Oxygen saturation is an important parameter in cases of COPD, but there are insufficient data on the role of pulse oximetry in patients with COPD, moreso in diseases across its spectrum, such as chronic bronchitis and emphysema. We assessed the performance of pulse oximetry in acute respiratory failure of patients with COPD. This was a cross-sectional, observational study. We studied 50 subjects with COPD admitted to the Government General Hospital, a 1,000-bed tertiary referral center in Guntur, India, from June 2013 to July 2013. Simultaneous reading of S(pO2) by a handheld pulse oximeter and S(aO2) by an automated arterial blood gas analyzer were taken. Pulse oximetry was sufficiently sensitive (84.60%) to hypoxemia in respiratory failure to be used in clinical situations. The mean difference (bias) between SaO2 and S(pO2) was -3.98 (95% CI -4.68 to 3.28). There was less sensitivity (82% vs. 85%) and positive predictive value (69% vs. 85%) of the pulse oximeter to respiratory failure in subjects with chronic bronchitis versus emphysema. Pulse oximetry performed poorly in comparison with the invasive arterial blood gas analysis. The variability of the readings was greater in the subjects with chronic bronchitis than in those with emphysema.

Utility and feasibility of integrating pulse oximetry into the routine assessment of young infants at primary care clinics in Karachi, Pakistan: a cross-sectional study.

BackgroundHypoxemia may occur in young infants with severe acute illnesses or congenital cardiac anomalies, but is not reliably detected on physical exam. Pulse oximetry (PO) can be used to detect hypoxemia, but its application in low-income countries has been limited, and its feasibility in the routine assessment of young infants (aged 0–59 days) has not been previously studied. The aim of this study was to characterize the operational feasibility and parent/guardian acceptability of incorporating PO into the routine clinical assessment of young infants in a primary care setting in a low-income country.MethodsThis was a cross-sectional study of 862 visits by 529 infants at two primary care clinics in Karachi, Pakistan (March to June, 2013). After clinical assessment, oxygen saturation (Sp02) was measured by a handheld PO device (Rad-5v, Masimo Corporation) according to a standardized protocol. Performance time (PT) was the time between sensor placement and attainment of an acceptable PO reading (i.e., stable SpO2 + 1 % for at least 10 s, heart rate displayed, and adequate signal indicators). PT included the time for one repeat attempt at a different anatomical site if the first attempt did not yield an acceptable reading within 1 min. Parent/guardian acceptability of PO was based on a questionnaire and unprompted comments about the procedure. All infants underwent physician assessment.ResultsAcceptable PO readings were obtained in ≤1 and ≤5 min at 94.4 % and 99.8 % of visits, respectively (n = 862). Median PT was 42 s (interquartile range 37; 50). Parents/guardians overwhelmingly accepted PO (99.6 % overall satisfaction, n = 528 first visits). Of 10 infants with at least one visit with Sp02 <92 % on a first PO attempt, 3 did not have a significant acute illness on physician assessment. There were no PO-related adverse events.DiscussionUsing a commercially available handheld pulse oximeter, acceptable Sp02 measurements were obtained in nearly all infants in under 1 minute. The procedure was readily integrated into existing assessment pathways and parents/guardians had positive views of the technology.ConclusionsWhen incorporated into routine clinical assessment of young infants at primary care clinics in a low-income country, PO was feasible and acceptable to parents/guardians. Future research is needed to determine if the introduction of routine PO screening of young infants will improve outcomes in low-resource settings.

The Effect Of Altitude On Heart Rate, SpO2 And RPE In Adolescent Male Lacrosse Players

Over the past 10 years, the sport of lacrosse has witnessed tremendous growth (1). The result is an increase in competitive opportunities in different regions of the country, such as the Vail (CO) Lacrosse Shootout (2). PURPOSE: An observational field study was conducted on lacrosse players, acclimated to 137 m (450 feet), competing in a 4-day tournament at 2484 m (8,150 feet). METHODS: Nineteen males participated in a U-17 summer lacrosse tournament. Mean age was 16.2 + 0.9 years. All had competed for their high school team in the spring and were now part of an independent travel team. The University's IRB approved the study. Informed consent was obtained from all subjects and their parents. A Nonin model 8000H handheld pulse oximeter was used to gather both heart rate and oxygen saturation. Borg's 15 point scale was used to obtain ratings of perceived exertion. Initial readings were taken during practice at sea level. Players arrived at altitude one or two days prior to the first competition. Contests were on four consecutive days and players participated in 3, 3, 2 and 1 games, respectively. Readings were taken before and after contests as well as when players came off the field during the games. RESULTS: Selected results include * data from one injured player and one sick player missingTableCONCLUSION: Observations from this field study demonstrate that non-acclimated adolescent male lacrosse players participated successfully in competition at altitude despite SpO2 values below normal. 1. US 2009 Participation Survey US Lacrosse National Headquarters, Baltimore, MD http://www.uslacrosse.org/LinkClick.aspx?fileticket=LCKgL10P6mk%3D&tabid=2800 2. Vail Lacrosse Shootout - http://www.vaillacrosse.com/

Walkway Length, But Not Turning Direction, Determines the Six-Minute Walk Test Distance in Individuals With Stroke

Ng SS, Tsang WW, Cheung TH, Chung JS, To FP, Yu PC. Walkway length, but not turning direction, determines the six-minute walk test distance in individuals with stroke. Objectives To examine (1) the effect of different walkway distances, and (2) turning directions on the six-minute walk test (6MWT) in subjects with stroke. Design A cross-sectional study. Setting University-based rehabilitation center. Participants Subjects (N=26) with chronic stroke. Interventions Not applicable. Main Outcome Measures Total distance covered and number of turns in the 6MWT with different walkway lengths (10-, 20-, and 30-m walkway distances) and turning directions (turning to affected side and unaffected side); rate of perceived exertion (RPE) using Borg Scale, and heart rate (HR) using handheld pulse oximeter recorded before and immediately after the test. Results The distance covered and the number of turns in the 6MWT were significantly different between different walkway lengths ( P<.05), with the longest distance covered and lowest number of turns in the 30-m walkway distance. For all walkway lengths, turning to the affected or unaffected side did not result in significant differences in the distance covered and the number of turns in the 6MWT. Significant increases were found between the pretest and posttest for the HR and RPE ( P<.05) in all testing conditions. There was no significant effect of walkway distance and turning direction on the change in HR and RPE between the 6 conditions of the 6MWT. Conclusions Different walkway distances have a significant effect on the distance covered in the 6MWT, whereas turning direction did not significantly affect the distance covered in the 6MWT.

Mechanical airway obstruction from laryngeal mask airway cuff

The laryngeal mask airway (LMA) classic has been found useful in airway management of both routine and emergency unexpected failed intubations. We report a case of mechanical airway obstruction from anterior in folding of the laryngeal mask airway classical cuff. The anaesthetic record of a 55-year-old 70 kg female patient fora left sided total hip replacement that had a failed spinal and was augmented with the laryngeal mask airway. Near complete airway obstruction developed after the size 4 laryngeal mask airway classic was inserted and the cuff inflated with 30 ml of air. The reduced reservoir volume and the desaturation that ensued as detected by the portable handheld pulse oximeter alerted the anesthesiologist and called for a check which was not corrected by any head and neck manoeuvre. On withdrawal of the laryngeal mask airway, the cuff was noted to have folded unto the fresh gas aperture thereby obstructing ventilation and oxygenation of the patient. Monitoring the monitors and quick reassessment of laryngeal cuff placement guaranties the evasion of anaesethetic catastrophes.

The effect of external nasal dilators on blood oxygen levels in dental patients

BACKGROUND. The authors conducted a study to examine the use of external nasal dilators, or ENDs, on dental patients and to determine whether the subjective improvement in comfort level noted in dental patients using ENDs is accompanied by a rise in the level of oxygen saturation as measured by pulse oximetry, or SpO2. The authors used a hand-held pulse oximeter to monitor 45 patients' SpO2 levels during routine dental procedures. The data suggest that dental procedures in general result in a lowering of the SpO2 level and that patients using an END do experience a rise in the SpO2 level. The data do not clearly establish that the increase in patient comfort with use of an END is due to a rise in the SpO2 level. The results of this study demonstrate that the use of an END facilitates nasal breathing in dental patients.