scholarly journals The Use of Pulse Oximetry in the Assessment of Acclimatization to High Altitude

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1263
Author(s):  
Tobias Dünnwald ◽  
Roland Kienast ◽  
David Niederseer ◽  
Martin Burtscher
Keyword(s):  
Pulse Oximetry ◽  
High Altitude ◽  
Acute Mountain Sickness ◽  
Measurement Methods ◽  
Peripheral Oxygen Saturation ◽  
Hypoxia Exposure ◽  
Lower Spo2 ◽  
Time Courses ◽  
Finger Pulse ◽  
Pulse Oximeters

Background: Finger pulse oximeters are widely used to monitor physiological responses to high-altitude exposure, the progress of acclimatization, and/or the potential development of high-altitude related diseases. Although there is increasing evidence for its invaluable support at high altitude, some controversy remains, largely due to differences in individual preconditions, evaluation purposes, measurement methods, the use of different devices, and the lacking ability to interpret data correctly. Therefore, this review is aimed at providing information on the functioning of pulse oximeters, appropriate measurement methods and published time courses of pulse oximetry data (peripheral oxygen saturation, (SpO2) and heart rate (HR), recorded at rest and submaximal exercise during exposure to various altitudes. Results: The presented findings from the literature review confirm rather large variations of pulse oximetry measures (SpO2 and HR) during acute exposure and acclimatization to high altitude, related to the varying conditions between studies mentioned above. It turned out that particularly SpO2 levels decrease with acute altitude/hypoxia exposure and partly recover during acclimatization, with an opposite trend of HR. Moreover, the development of acute mountain sickness (AMS) was consistently associated with lower SpO2 values compared to individuals free from AMS. Conclusions: The use of finger pulse oximetry at high altitude is considered as a valuable tool in the evaluation of individual acclimatization to high altitude but also to monitor AMS progression and treatment efficacy.

scholarly journals Ethnic Differences on Cardiac Rhythms and Autonomic Nervous System Responses During a High-Altitude Trek: A Pilot Study Comparing Italian Trekkers to Nepalese Porters

2021 ◽  
Vol 12 ◽  
Author(s):  
Vittore Verratti ◽  
Alessandro Tonacci ◽  
Danilo Bondi ◽  
Annalisa Chiavaroli ◽  
Claudio Ferrante ◽  
...  
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
High Altitude ◽  
Sympathetic Activity ◽  
Activity Measurement ◽  
Peripheral Oxygen Saturation ◽  
Altitude Hypoxia ◽  
Autonomic Nervous ◽  
Hypoxia Exposure

Altitude hypoxia exposure results in increased sympathetic activity and heart rate due to several mechanisms. Recent studies have contested the validity of heart rate variability (HRV) analysis on sympathetic activity measurement. But the plethora of HRV metrics may provide meaningful insights, particularly if linked with cardiovascular and autonomic nervous system parameters. However, the population-specific nature of HRV and cardiorespiratory response to altitude hypoxia are still missing. Six Italian trekkers and six Nepalese porters completed 300 km of a Himalayan trek. The ECG analysis was conducted at baseline, and before (bBC) and after (aBC) the high-altitude (HA) circuit. Urine was collected before and after the expedition in Italians, for assessing catecholamines. Heart rate increased with altitude significantly (p < 0.001) in the Italian group; systolic (p = 0.030) and diastolic (p = 0.012) blood pressure, and mean arterial pressure (p = 0.004) increased with altitude. Instead, pulse pressure did not change, although the Nepalese group showed lower baseline values than the Italians. As expected, peripheral oxygen saturation decreased with altitude (p < 0.001), independently of the ethnic groups. Nepalese had a higher respiratory rate (p = 0.007), independent of altitude. The cardiac vagal index increased at altitude, from baseline to bBC (p = 0.008). Higuchi fractal dimension (HFD) showed higher basal values in the Nepalese group (p = 0.041), and a tendency for the highest values at bBC. Regarding the urinary catecholamine response, exposure to HA increased urinary levels, particularly of norepinephrine (p = 0.005, d = 1.623). Our findings suggest a better cardiovascular resilience of the Nepalese group when compared with Italians, which might be due to an intrinsic adaptation to HA, resulting from their job.

scholarly journals Pulse oximetry to predict the onset of acute mountain sickness: a literature review

2021 ◽  
Vol 13 (9) ◽  
pp. 378-384
Author(s):  
Thomas Bicknell
Keyword(s):  
Literature Review ◽  
Pulse Oximetry ◽  
High Altitude ◽  
Acute Mountain Sickness ◽  
Subjective Symptom ◽  
Allied Health Professionals ◽  
Scoping Literature Review ◽  
Mountain Sickness ◽  
As Stress ◽  
Symptom Recall

Acute mountain sickness (AMS) is a common illness affecting people ascending to high altitudes. AMS may progress rapidly, and can be fatal if symptoms are neglected, acclimatisation processes fail or if the ascent continues. For many patients with AMS or AMS symptoms, medical assistance is given by mountain rescue and allied health professionals. Currently, the prediction of AMS in the high-altitude environment relies upon recognising and tracking subjective symptoms. However, owing to psychophysical factors commonly associated with high-altitude travel, such as stress and fatigue, subjective symptom recall is innately at risk of bias. There is no objective method for predicting AMS. This scoping literature review analyses the accuracy of pulse oximetry as a tool for predicting the onset of AMS.

Effect of intermittent normobaric hypoxia exposure on acclimatization to high altitude by air induction

2021 ◽  
Vol 12 (10) ◽  
pp. 58-63
Author(s):  
Gopinath Bhaumik ◽  
Deepak Dass ◽  
Dishari Ghosh ◽  
Kishan Singh ◽  
Maram Prasanna Kumar Reddy
Keyword(s):  
Oxygen Saturation ◽  
High Altitude ◽  
Sea Level ◽  
Acute Mountain Sickness ◽  
Treated Group ◽  
Physiological Parameters ◽  
Normobaric Hypoxia ◽  
Hypoxia Exposure ◽  
Intermittent Normobaric Hypoxia ◽  
High Altitude Illness

Background: In emergency like condition, defence personnel are deployed to high altitude without proper acclimatization. Maladaption at high altitude leads to high altitude illness like acute mountain sickness (AMS), high altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE) which hampers the operational capabilities. Aims and Objectives: The aim of the present study was to assess the effect of intermittent normobaric hypoxia exposure (IHE) at sea level on different physiological responses during initial days of acclimatization at 3500m and 4000m altitudes in acute induction. Materials and Methods: The IHE subjects were exposed to 12% FIO2 (equivalent altitude 14500 ft) for 4 hrs/day for 4 consecutive days at sea level and 5th day they were inducted by air to 3500m altitude. Baseline recording of different physiological parameters like cardiovascular, respiratory, oxygen saturation and AMS score were measured at sea level as well as 3500m altitude on daily basis for 6 days to assess acclimatization status. To confirm acclimatization status at 3500m, on fifth day the IHE group subjects were transported by road to 4000m and again measured different basal physiological parameters (like cardiovascular, oxygen saturation and AMS score) for four consecutive days. Results: Different physiological parameters of IHE treated group were stabilized by day 4 of air induction at 3500m altitude. Whereas, at 4000m altitude, these parameters were stabilized by day 2 of induction. Conclusion: Acclimatization schedules of four days at 3500m and two days at 4000m are essential to avoid malacclimatization/or high-altitude illness.

Accuracy of pulse oximetry to estimate HbO2 fraction of total Hb during exercise

1989 ◽  
Vol 67 (1) ◽  
pp. 300-304 ◽  
Author(s):  
S. K. Powers ◽  
S. Dodd ◽  
J. Freeman ◽  
G. D. Ayers ◽  
H. Samson ◽  
...  
Keyword(s):  
Pulse Oximetry ◽  
Power Output ◽  
Healthy Subjects ◽  
Correlation Coefficients ◽  
Cycle Ergometer ◽  
Hypoxic Conditions ◽  
Arterial Blood ◽  
Wide Range ◽  
Finger Pulse ◽  
Pulse Oximeters

The accuracy of two pulse oximeters (Ohmeda 3700 and Biox IIa) was evaluated during cycle ergometer incremental exercise in 10 healthy subjects. The exercise protocol began at 30 W with the power output being increased 15 W.min-1 until volitional fatigue. Ear and finger probe pulse oximetry measurements of available hemoglobin (%Spo2) were compared with arterial oxyhemoglobin fraction of total hemoglobin (%HbO2) measured directly from arterial blood samples using a CO-oximeter. To provide a wide range of %HbO2 values, four subjects exercised under hypoxic conditions [inspired partial pressure of O2 (PIo2) = 107 Torr], while the remaining six subjects exercised under normoxic conditions (PIo2 = 150 Torr). Because carboxyhemoglobin (HbCO) or methemoglobin (MetHb) is not measured by pulse oximeters, %HbO2 was corrected for HbCO and MetHb and expressed as percent arterial O2 saturation of available Hb (%Sao2). Small and insignificant differences (P greater than 0.05) existed between SpO2 (all 3 instruments) and %SaO2 at the lowest work rate and the highest power output achieved. Regression analyses of %SpO2 vs. %SaO2 produced correlation coefficients of r = 0.82 [standard error of the estimate [(SEE) = 1.79], r = 0.89 (SEE = 1.48), and r = 0.93 (SEE = 1.14) for the Biox IIa, Ohmeda 3700 (ear), and the Ohmeda 3700 (finger) pulse oximeters, respectively. We conclude that pulse oximetry, within the above limits of accuracy, is useful in estimating %SaO2 during exercise in healthy subjects.

scholarly journals Wearable Finger Pulse Oximetry for Continuous Oxygen Saturation Measurements During Daily Home Routines of Patients With Chronic Obstructive Pulmonary Disease (COPD) Over One Week: Observational Study (Preprint)

2018 ◽  
Author(s):  
Joren Buekers ◽  
Jan Theunis ◽  
Patrick De Boever ◽  
Anouk W Vaes ◽  
Maud Koopman ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Pulmonary Disease ◽  
Chronic Obstructive ◽  
Blood Oxygen ◽  
Obstructive Pulmonary Disease ◽  
Copd Patients ◽  
Finger Pulse ◽  
Pulse Oximeters

BACKGROUND Chronic obstructive pulmonary disease (COPD) patients can suffer from low blood oxygen concentrations. Peripheral blood oxygen saturation (SpO2), as assessed by pulse oximetry, is commonly measured during the day using a spot check, or continuously during one or two nights to estimate nocturnal desaturation. Sampling at this frequency may overlook natural fluctuations in SpO2. OBJECTIVE This study used wearable finger pulse oximeters to continuously measure SpO2 during daily home routines of COPD patients and assess natural SpO2 fluctuations. METHODS A total of 20 COPD patients wore a WristOx2 pulse oximeter for 1 week to collect continuous SpO2 measurements. A SenseWear Armband simultaneously collected actigraphy measurements to provide contextual information. SpO2 time series were preprocessed and data quality was assessed afterward. Mean SpO2, SpO2 SD, and cumulative time spent with SpO2 below 90% (CT90) were calculated for every (1) day, (2) day in rest, and (3) night to assess SpO2 fluctuations. RESULTS A high percentage of valid SpO2 data (daytime: 93.27%; nocturnal: 99.31%) could be obtained during a 7-day monitoring period, except during moderate-to-vigorous physical activity (MVPA) (67.86%). Mean nocturnal SpO2 (89.9%, SD 3.4) was lower than mean daytime SpO2 in rest (92.1%, SD 2.9; P<.001). On average, SpO2 in rest ranged over 10.8% (SD 4.4) within one day. Highly varying CT90 values between different nights led to 50% (10/20) of the included patients changing categories between desaturator and nondesaturator over the course of 1 week. CONCLUSIONS Continuous SpO2 measurements with wearable finger pulse oximeters identified significant SpO2 fluctuations between and within multiple days and nights of patients with COPD. Continuous SpO2 measurements during daily home routines of patients with COPD generally had high amounts of valid data, except for motion artifacts during MVPA. The identified fluctuations can have implications for telemonitoring applications that are based on daily SpO2 spot checks. CT90 values can vary greatly from night to night in patients with a nocturnal mean SpO2 around 90%, indicating that these patients cannot be consistently categorized as desaturators or nondesaturators. We recommend using wearable sensors for continuous SpO2 measurements over longer time periods to determine the clinical relevance of the identified SpO2 fluctuations.

Decreased contrast sensitivity at high altitude

2019 ◽  
Author(s):  
Katrin Gekeler ◽  
Andreas Schatz ◽  
Manuel Dominik Fischer ◽  
Kai Schommer ◽  
Katrin Boden ◽  
...  
Keyword(s):  
Visual Acuity ◽  
High Altitude ◽  
Contrast Sensitivity ◽  
Visual Processing ◽  
Repeated Measures ◽  
Healthy Subjects ◽  
Acute Mountain Sickness ◽  
Clinical Importance ◽  
Peripheral Oxygen Saturation ◽  
Altitude Exposure

Background/aimsThe aim of this study was to investigate a change in visual acuity and contrast sensitivity (CS) during high altitude exposure in healthy subjects due to the effects of hypobaric hypoxia. This study is related to the Tübingen High Altitude Ophthalmology study.MethodsVisual acuity and Weber CS were tested monocularly using the Freiburger Visual Acuity and Contrast Test under standardised conditions in 14 healthy subjects at high altitude at the Capanna Margherita (4559 m, Italy) and compared with baseline measurements in Tübingen (341 m, Germany). Intraindividual differences between baseline and follow-up examinations were calculated by multivariate analysis of variance for repeated measures. Clinical parameters of peripheral oxygen saturation (SpO2) and heart rate (HR) as well as scores for acute mountain sickness (AMS) were correlated to psychophysical tests by Pearson’s correlation coefficient.ResultsA significant decrease in CS with a mean effect size of −0.13 logCS was found for Weber CS (day 1=−0.16±0.22, p=0.01; day 2=−0.10±0.2, p=0.049; day 3=−0.12±0.19, p=0.03) at high altitude compared with baseline. Visual acuity remained unchanged. Decreased CS correlated with SpO2 (r=0.53, p=0.046) but not with HR (r=− 0.16, p=0.59) and occurred irrespective of AMS at high altitude.ConclusionHigh altitude exposure leads to decreased CS. Changes occur independent of AMS. This finding is of clinical importance to trekkers and mountaineers exposed to high altitude as visual processing in particular under mesopic conditions at dusk and dawn is altered. Furthermore, it provides novel insight into hypoxia related changes in CS function.

scholarly journals Wearable pulse oximeters in the prompt detection of hypoxaemia and during movement: a diagnostic accuracy study (Preprint)

2021 ◽  
Author(s):  
Mauro Santos ◽  
Sarah Vollam ◽  
Marco A.F. Pimentel ◽  
Carlos Areia ◽  
Louise Young ◽  
...  
Keyword(s):  
Mean Squared Error ◽  
Characteristic Curve ◽  
Hospital Setting ◽  
Wireless Transmission ◽  
Transmission Mode ◽  
Peripheral Oxygen Saturation ◽  
Hypoxia Exposure ◽  
Arterial Blood ◽  
Patients At Risk ◽  
Pulse Oximeters

BACKGROUND Commercially available wearable (ambulatory) pulse oximeters have been recommended as a method for managing patients at risk of physiological deterioration, such as active patients with COVID-19 disease receiving care in hospital isolation rooms, however, their reliability is unclear to use in the hospital setting. OBJECTIVE We report the performance of wearable pulse oximeters in a simulated clinical setting when challenged by motion and low levels of arterial blood oxygen (SaO2). METHODS The performance of one wrist-worn (Wavelet) and three finger-worn (CheckMeTM O2+, AP-20 and WristOx2® 3150) wearable, wireless transmission-mode, pulse oximeters was evaluated. Seven motion tasks were performed: At rest, Sit-to-Stand, Tapping, Rubbing, Drinking, Turning Pages, and Using a Tablet. Hypoxia exposure followed, in which inspired gases were adjusted to achieve decreasing SaO2 levels at 100%, 95%, 90%, 87%, 85%, 83% and 80%. Peripheral oxygen saturation (SpO2) estimates were compared with simultaneous SaO2 samples to calculate the root mean squared error (RMSE). Area under the receiver-operating characteristic curve was used to analyse the detection of hypoxaemia, SaO2 < 90%. RESULTS SpO2 estimates matching 215 SaO2 samples in both study phases, from 33 participants, were analysed. Tapping, rubbing, turning pages and using a tablet degraded SpO2 estimation (RMSE > 4% for a least one device). All finger-worn pulse oximeters detected hypoxaemia, with an overall sensitivity ≥ 0.87 and specificity ≥ 0.80, comparable to that of the Philips MX450. CONCLUSIONS The SpO2 accuracy of wearable finger-worn pulse oximeters was within that required by the International Organization for Standardization guidelines. Performance was degraded by motion, but all were capable of detecting hypoxaemia. Our findings support the use of wearable, wireless transmission-mode, pulse oximeters to detect the onset of clinical deterioration in hospital settings. CLINICALTRIAL ISRCTN61535692; http://www.isrctn.com/ISRCTN61535692 INTERNATIONAL REGISTERED REPORT RR2-10.1136/bmjopen-2019-034404

Optic nerve sheath diameter changes at high altitude and in acute mountain sickness: meta-regression analyses

2020 ◽  
pp. bjophthalmol-2020-317717
Author(s):  
Tou-Yuan Tsai ◽  
George Gozari ◽  
Yung-Cheng Su ◽  
Yi-Kung Lee ◽  
Yu-Kang Tu
Keyword(s):  
Optic Nerve ◽  
High Altitude ◽  
Acute Mountain Sickness ◽  
Optic Nerve Sheath Diameter ◽  
Optic Nerve Sheath ◽  
Cochrane Library ◽  
Regression Analyses ◽  
Spline Regression ◽  
Nerve Sheath ◽  
Mountain Sickness

Background/aimsTo assess changes in optic nerve sheath diameter (ONSD) at high altitude and in acute mountain sickness (AMS).MethodsCochrane Library, EMBASE, Google Scholar and PubMed were searched for articles published from their inception to 31st of July 2020. Outcome measures were mean changes of ONSD at high altitude and difference in ONSD change between subjects with and without AMS. Meta-regressions were conducted to investigate the relation of ONSD change to altitude and time spent at that altitude.ResultsEight studies with 248 participants comparing ONSD from sea level to high altitude, and five studies with 454 participants comparing subjects with or without AMS, were included. ONSD increased by 0.14 mm per 1000 m after adjustment for time (95% CI: 0.10 to 0.18; p<0.01). Restricted cubic spline regression revealed an almost linear relation between ONSD change and time within 2 days. ONSD was greater in subjects with AMS (mean difference=0.47; 95% CI: 0.14 to 0.80; p=0.01; I2=89.4%).ConclusionOur analysis shows that ONSD changes correlate with altitude and tend to increase in subjects with AMS. Small study number and high heterogeneity are the limitations of our study. Further large prospective studies are required to verify our findings.

scholarly journals The Oxygen Transport Triad in High-Altitude Pulmonary Edema: A Perspective from the High Andes

2021 ◽  
Vol 18 (14) ◽  
pp. 7619
Author(s):  
Gustavo Zubieta-Calleja ◽  
Natalia Zubieta-DeUrioste
Keyword(s):  
Pulmonary Edema ◽  
High Altitude ◽  
Oxygen Transport ◽  
Acute Mountain Sickness ◽  
Breath Holding ◽  
Acid Base Balance ◽  
Initial Exposure ◽  
High Altitude Pulmonary Edema ◽  
Tolerance To Hypoxia ◽  
Dynamic Pump

Acute high-altitude illnesses are of great concern for physicians and people traveling to high altitude. Our recent article “Acute Mountain Sickness, High-Altitude Pulmonary Edema and High-Altitude Cerebral Edema, a View from the High Andes” was questioned by some sea-level high-altitude experts. As a result of this, we answer some observations and further explain our opinion on these diseases. High-Altitude Pulmonary Edema (HAPE) can be better understood through the Oxygen Transport Triad, which involves the pneumo-dynamic pump (ventilation), the hemo-dynamic pump (heart and circulation), and hemoglobin. The two pumps are the first physiologic response upon initial exposure to hypobaric hypoxia. Hemoglobin is the balancing energy-saving time-evolving equilibrating factor. The acid-base balance must be adequately interpreted using the high-altitude Van Slyke correction factors. Pulse-oximetry measurements during breath-holding at high altitude allow for the evaluation of high altitude diseases. The Tolerance to Hypoxia Formula shows that, paradoxically, the higher the altitude, the more tolerance to hypoxia. In order to survive, all organisms adapt physiologically and optimally to the high-altitude environment, and there cannot be any “loss of adaptation”. A favorable evolution in HAPE and pulmonary hypertension can result from the oxygen treatment along with other measures.

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