Changes In SpO2 Research Articles

Changes in Oxygen Saturation and Mean Arterial Pressure With Inhaled Epoprostenol in Transport.

Patients with hypoxemic respiratory failure have traditionally been considered one of the riskiest patient populations to transport, given the potential for desaturation with movement. We performed a retrospective cohort study to analyze our experience using inhaled epoprostenol in transport, with a primary objective of assessing change in the oxygen saturation throughout the transport. The transport records of patients with severe hypoxemic respiratory failure or right heart failure, transported on inhaled epoprostenol, were reviewed. The primary outcome was the change in SpO2 from the start of the inhaled epoprostenol transport to the time of handover of care at the receiving institution. The secondary outcome was the change in the mean arterial pressure (MAP). Comparing the initial SpO2 to the final, there was no significant difference in oxygenation between time 0 and the transfer of care at the receiving hospital at 91% versus 93% (interquartile range [IQR] 86.0-93.5 vs 87.5-96.0, P = .49). Comparing the SpO2 for those who had inhaled epoprostenol started by the transport team showed a larger change at 86% compared to 93% (IQR: 83.0-91.0 vs 86.5-94.5, P = .04). There was no change in the median MAP from time 0 to the end of the transport (77 vs 75 mm Hg, IQR, 67.5-84.8 vs 68.5-85.8, P = .70). In this study, patients with severe cardiopulmonary compromise transported on inhaled epoprostenol had no significant change in their median oxygen saturations, with the overall population increasing from 91% to 93%. When inhaled epoprostenol was initiated by the transport team, the improvement was clinically and statistically significant with an increase in SpO2 from 86% to 93%, with a final oxygen saturation comparable to those who were on the medication at the time of the team's arrival.

Investigation of Photoplethysmography Behind the Ear for Pulse Oximetry in Hypoxic Conditions with a Novel Device (SPYDR)

Photoplethysmography (PPG) is a valuable technique for noninvasively evaluating physiological parameters. However, traditional PPG devices have significant limitations in high-motion and low-perfusion environments. To overcome these limitations, we investigated the accuracy of a clinically novel PPG site using SPYDR®, a new PPG sensor suite, against arterial blood gas (ABG) measurements as well as other commercial PPG sensors at the finger and forehead in hypoxic environments. SPYDR utilizes a reflectance PPG sensor applied behind the ear, between the pinna and the hairline, on the mastoid process, above the sternocleidomastoid muscle, near the posterior auricular artery in a self-contained ear cup system. ABG revealed accuracy of SPYDR with a root mean square error of 2.61% at a 70–100% range, meeting FDA requirements for PPG sensor accuracy. Subjects were also instrumented with SPYDR, as well as finger and forehead PPG sensors, and pulse rate (PR) and oxygen saturation (SpO2) were measured and compared at various reduced oxygen profiles with a reduced oxygen breathing device (ROBD). SPYDR was shown to be as accurate as other sensors in reduced oxygen environments with a Pearson’s correlation >93% for PR and SpO2. In addition, SPYDR responded to changes in SpO2 up to 50 s faster than PPG measurements at the finger and forehead.

Oxygen Saturation in Childhood at High Altitude: A Systematic Review.

Background: It is well known that oxygen saturation as measured by pulse oximetry (SpO2) decreases as altitude increases. However, how SpO2 changes across childhood, and more specifically during sleep/wake states, at different high altitudes are less well understood. We aimed to perform a systematic review of all studies with direct SpO2 measurement in healthy children living at high altitude (>2500 meters above sea level) to address these questions. Methods: MEDLINE, EMBASE, and SciELO databases were searched up to December 2018. Two independent reviewers screened the literature and extracted relevant data. Results: Of 194 references, 20 studies met the eligibility criteria. Meta-analysis was not possible due to the use of different oximeters and/or protocols for data acquisition and reporting of different SpO2 central tendency and dispersion measures. The most relevant findings from the data were: (1) SpO2 is lower as altitude increases; (2) at high altitude, SpO2 improves with age through childhood; (3) SpO2 is lower during sleep and feeding in comparison to when awake, this SpO2 gap between wake and sleep states is more evident in the first months of life and narrows later in life; (4) SpO2 dispersion (interindividual variation) is higher at younger ages, and more so during sleep; (5) In 6/20 studies, the SpO2 values were nonnormally distributed with a consistent left skew. Conclusions: At high altitude, the mean/median SpO2 increases in children with aging; a significant gap between wake and sleep states is seen in the first months of life, which narrows as the infant gets older; SpO2 dispersion at high altitude is wider at younger ages; at high altitude, SpO2 shows a nonnormal distribution skewed to the left; this bias becomes more evident as altitude increases, at younger ages and during sleep.

Lung function and oxygen saturation after participation in Norseman Xtreme Triathlon.

To examine evidence of exercise-induced bronchoconstriction (EIB) defined as ≥10% reduction in forced expiratory volume in one second (FEV1 ) and exercise-induced arterial hypoxemia (EIAH) defined as ≥4% reduction in oxygen saturation (SpO2 ) from before to after participation in the Norseman Xtreme Triathlon. Secondarily, to assess whether changes in FEV1 and SpO2 are related to respiratory symptoms, training volume, and race time. In this quasi-experimental non-controlled study, we included 63 triathletes (50♂/13♀) aged 40.3 (±9.0) years (mean±SD). Fifty-seven (46♂/11♀) measured lung function and 54 (44♂/10♀) measured SpO2 before the race, 8-10minutes after the race (post-test 1) and the day after the race (post-test 2). Respiratory symptoms and training volume were recorded with modified AQUA questionnaire. ANOVA for repeated measures was used to detect differences in lung function and SpO2 . Statistical significance was accepted at 0.05 level. Twenty-six participants (46%) presented with EIB at post-test 1 and 16 (28%) at post-test 2. Lung function variables were significantly reduced from baseline to post-test 1 and 2. Thirty-five participants (65%) showed evidence of mild to moderate EIAH. No significant correlations were observed except a weak correlation between maximal reduction in FEV1 and respiratory symptoms (r=0.35, P=.016). Our results demonstrated that 46% of the participants presented with EIB and 65% showed evidence of EIAH after the Norseman Xtreme Triathlon. Changes in FEV1 and SpO2 were not correlated to weekly training hours or race time. We observed a weak correlation between maximal reduction in FEV1 and respiratory symptoms.

Time course of blood oxygen saturation responding to short-term fine particulate matter among elderly healthy subjects and patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) often experience deteriorating gaseous exchange which in turn may result in declines in blood oxygen saturation (SpO2). Increasing evidence has also shown that elevated levels of fine particulate matter (PM2.5) may contribute to COPD pathogenesis. However, the acute effects of PM2.5 on SpO2 among COPD patients remain unclear, especially for its time course. Therefore, we conducted this panel study with 3-day real-time monitoring for personal PM2.5 exposure and concurrent SpO2 of 39 participants (20 COPD patients, 19 healthy participants), aged 60 to 90 years, in Hong Kong to explore the acute effects of personal PM2.5 exposure on SpO2 (within minutes to hours). We applied a linear mixed effect model to examine the associations between personal PM2.5 and SpO2, while adjusting for temporal trend, personal characteristics, weather conditions, and co-exposure to gaseous pollutants (ambient ozone, nitrogen dioxides, carbon monoxide, and atmospheric pressure). We found that short-term exposure to PM2.5 might result in acute declines of SpO2 within minutes, and the effects would last for several hours. An interquartile range increase of personal PM2.5 exposure (17.2 μg/m3) was associated with −0.19% (95% CI: −0.26% to −0.12%) changes of concurrent SpO2 for all participants. The most significant decline was observed at lag0-3 h, and then became insignificant at lag0-12 h. At lag0-1 h, estimated mean changes of SpO2 were −0.40% (95% CI: −0.55% to −0.24%) for COPD patients and −0.09% (95% CI: −0.23% to 0.06%) for healthy participants. Compared with healthy participants, the effects of PM2.5 exposure on SpO2 for COPD patients were slightly stronger and more acute. Reducing PM2.5 concentrations might be a useful approach to improve health status and reduce exacerbations for COPD patients.

Noninvasive Pulmonary Hemodynamic Evaluation in Athletes With Exercise-Induced Hypoxemia

Pulmonary capillary stress failure is potentially involved in exercise-induced hypoxemia (ie, a significant fall in hemoglobin oxygen saturation [Spo2]) during sea level exercise in endurance-trained athletes. It is unknown whether there are specific properties of pulmonary vascular function in athletes exhibiting oxygen desaturation. Ten endurance-trained athletes with exercise-induced hypoxemia (EIH), nine endurance-trained athletes with no exercise-induced hypoxemia (NEIH), and 10 untrained control subjects underwent an incremental exercise stress echocardiography coupled with lung diffusion capacity for carbon monoxide (Dlco) and lung diffusion capacity for nitric oxide (Dlno) testing. Functional adaptation of the pulmonary circulation was evaluated with measurements of mean pulmonary arterial pressure (mPAP), pulmonary capillary pressure, pulmonary vascular resistance (PVR), cardiac output (Qc), and pulmonary vascular distensibility (alpha) mathematically determined from the curvilinearity of the multi-point mPAP/Qc relation. EIH athletes exhibited a lower exercise-induced PVR decrease compared with the untrained and NEIH groups (P< .001). EIH athletes showed higher maximal mPAP compared with NEIH athletes (45.4 ± 0.9mmHg vs41.6 ± 0.9mmHg, respectively; P= .003); there was no difference between the NEIH and untrained subjects. Alpha was lower in the EIH group compared with the NEIH group (P< .05). Maximal mPAP, Pcap, and alpha were correlated with the fall of Spo2 during exercise (P< .01, P< .01, and P< .05). Dlno and Dlco increased with exercise in all groups, with no differences between groups. Dlno/Qc was correlated to the exercise-induced Spo2 changes (P< .05). EIH athletes exhibit higher maximal pulmonary vascular pressures, lower vascular distensibility, or exercise-induced changes in PVR compared with NEIH subjects, in keeping with pulmonary capillary stress failure or intrapulmonary shunting hypotheses.

Effects of osteopathic treatment versus static touch on heart rate and oxygen saturation in premature babies: A randomized controlled trial

BackgroundOsteopathic manipulative treatment (OMT) has been successfully tested in the context of preterm infants. No studies, however, have been conducted to investigate the OMT immediate effects on physiological measurements, such as partial oxygen saturation (SpO2) and heart rate (HR). The purpose of the present study was to assess the effect of osteopathic treatment on SpO2 and HR values and to compare it with 10 min of static touch. Materials and methodsNinety-six preterm infants (41 male), aged 33.5 weeks (±4.3) with mean weight at birth of 2067gr (±929) were recruited from the neonatal intensive care unit (NICU) of the Buzzi Hospital in Milan, and randomly allocated to two groups: OMT and Static Touch. Each protocol session consisted of: a) 5-min Pre-touch baseline recording, b) 10-min touch procedure, c) 5-min post-touch recording. Primary and secondary outcomes were, respectively, the baseline changes of HR and SpO2. ResultsThe 2 × 2 repeated measure ANOVA for HR showed a statistically significant effect (F (1,94) = 5.34; p < 0.02), revealing that the OMT group decreases the HR value at T2 (p = 0.006). In contrast, SpO2 analysis showed an increase of SpO2 value where the OMT group demonstrated higher values at T2 (p = 0.04). ConclusionResults from the present study suggest that a single osteopathic intervention may induce beneficial effects on preterm physiological parameters. Trial registrationClinicalTrials.gov identifier: NCT03833635 – Date: February 7, 2019.

Exercise-Induced Oxygen Desaturation during the 6-Minute Walk Test.

The 6-minute walk test (6MWT) is not intended to document oxygen (O2) desaturation during exertion but is often used for this purpose. Because of this, it only has modest reproducibility in determining the need for ambulatory O2 therapy in patients with cardiopulmonary disease. The diagnostic and prognostic value of detecting exertional O2 desaturation is still unknown. The aims of this study were to estimate the prevalence of O2 desaturation during a 6MWT based on pulse oximetry measurements at the beginning and end of a 6MWT in a clinical population of patients with suspected cardiopulmonary disease and to determine whether the pulmonary function test (PFT) can predict exercise-induced desaturation during a 6MWT. This retrospective cohort study reviewed the results of the 6MWT and the PFT (i.e., spirometry, lung volumes, and diffusion capacity) of all patients who were evaluated for suspected cardiopulmonary disease at an academic medical center during a 5-year study period. The patients were categorized into three groups based on the change in O2 saturation by pulse oximetry (SpO2) from start to end of the 6MWT: (1) SpO2 decreased by ≥3%; (2) SpO2 unchanged (−2 ≤ Δ ≤ 0%); and (3) SpO2 increased by ≥1%. Demographic, anthropometric, and lung function measurements were analyzed to determine which factors predicted O2 desaturation during the 6MWT. Of the 319 patients who underwent the 6MWT and the PFT from November 2005 until December 2010 (mean age = 54 ± 0.78 years, 63% women, 58% Whites, body mass index = 29.63 ± 8.10 kg/m2), 113 (35%) had a decreased SpO2, 146 (46%) had no change, and 60 (19%) had an increased SpO2 from the start to end of test. Our bivariate analysis found age, spirometric measures, and diffusion capacity for carbon monoxide (DLCO) had statistically significant inverse associations with the SpO2 change category (p < 0.001). Both a 3% and 4% drop in SpO2 during the 6MWT were statistically significantly associated with an older age, a higher prevalence of obstruction, and reduced forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, DLCO and 6-minute walk distance (6MWD). Multivariable logistic regression analyses revealed that only DLCO was a significant independent predictor of the change in SpO2 and a ≥ 4% O2 desaturation during a 6MWT. Receiver operating curve analysis indicates DLCO cut-off of 45% is 82% sensitive and 40% specific in identifying ≥4% O2 desaturators, with an area under the curve of 0.788 ± 0.039 (p < 0.001). The prevalence of a ≥ 3% oxygen desaturation via pulse oximetry during a 6MWT in our clinical population of patients with suspected cardiopulmonary disease was 35%. Although age, spirometric lung volumes, and DLCO had statistically significant unadjusted inverse associations with the change in SpO2 during a 6MWT, the DLCO is the only significant independent predictor of both the magnitude of the change in SpO2 and the occurrence of O2 desaturation of at least 4%, respectively, during the test. Clinical Implications: A DLCO cut-off of 45% may be useful in identifying patients at risk for exertional hypoxemia during a 6MWT.

Intravenous Application of Metronidazole, Ceftriaxone and Enrofloxacin in Dogs Anesthetized with Isoflurane: Impact of Hemodynamic and Cardiorespiratory Parameters

Background: The prophylactic use of antimicrobials in patients undergoing surgery is widely performed due to its power to reduce and control infections in the surgical site. Metronidazole, ceftriaxone and enrofloxacin are drugs widely used in veterinary medicine, even during anesthesia, either in healthy patients or under critical conditions. Despite several reports on hemodynamic reactions after intravenous application of antimicrobials in dogs, there are few studies on these effects in dogs undergoing anesthesia. The objective of this study was to evaluate the hemodynamic and cardiorespiratory effects of metronidazole, ceftriaxone and enrofloxacin in dogs anesthetized with isoflurane.Materials, Methods &amp; Results: Forty healthy bitches were used, equally divided into four experimental groups of 10 animals each: placebo group (PG), metronidazole group (MG), ceftriaxone group (CG) and enrofloxacin group (EG). After the experimental phase of data collection, all animals were submitted to ovariohysterectomy using the minimally invasive approach. A catheter was placed in the dorsal metatarsal artery for direct blood pressure monitoring, with systolic (SBP), mean (MBP) and diastolic (DBP) blood pressures were continuously monitored by means of a transducer connected to a multiparametric monitor. The others measured data were heart rate (HR), respiratory rate (RR), body temperature (T°C), carbon dioxide expired fraction (ETCO2), oxygen saturation of hemoglobin (SpO2) in T0 (time immediately before performing the treatment), 5 (T5), 10 (T10), 15 (T15), 20 (T20) and 30 (T30) minutes after administration of the antimicrobial. Anesthetic induction was performed with propofol and anesthetic maintenance was performed with isoflurane. After reaching anesthesia with a surgical plan, all parameters were measured before treatments were performed (T0). Then the sodium chloride solution (0.9% NaCl), 25 mg/kg of metronidazole, 30 mg/kg of ceftriaxone or 5 mg/kg of enrofloxacin was administered in cefalic vein. No complications were observed during anesthesia and surgery in all groups. The animals were monitored for three h after the end of the surgery, and then dispensed without prescription of antimicrobials in the recovery period. The HR showed a significant reduction in T5 and T30 compared to the baseline in EG. The RR had a significant increase in T30 in relation to T0 after the administration of 0.9% NaCl in PG. There were no statistically significant changes in HR for groups PG, MG and CG, and RR for groups EG, MG and CG. SBP and MBP had a significant decrease after 30 min of ceftriaxone application. There was a significant decrease in MBP at T5, T10 and T15 compared to baseline in EG. No changes in blood pressure were detected in PG and MG. The ToC showed a significant reduction from T10 to T30 in the GP, from T5 to T30 in the SG, in the T30 in the GM from T20 to T30 in the GC. For all groups, there were no changes in SpO2, ETCO2 and PAD during the study.Discussion: It was concluded that all studied antimicrobials can be used in prophylactic therapy in dogs, in doses recommended by the literature, as the observed changes are subject to correction and can be easily controlled by a qualified anesthetist. The antimicrobial that did not show cardiorespiratory and hemodynamic changes after intravenous application in bitches anesthetized with isoflurane was metronidazole, so its administration was considered safer when compared to enrofloxacin and ceftriaxone, under the conditions of this study, however its indication is punctual, being restricted to cases of infections by anaerobic agents.

One-Fifth of Children with Sickle Cell Anemia Show Exercise-Induced Hemoglobin Desaturation: Rate of Perceived Exertion and Role of Blood Rheology.

Perceived exertion is an important self-limiting factor influencing functional capacity in patients with sickle cell anemia (SCA). Exercise-related hemoglobin desaturation (EHD) may occur during a six-minute walking test (6MWT) and could influence the perceived rate of exertion. The aims of this study were (1) to compare the 6MWT responses (heart rate, perceived rate of exertion, and distance covered) between SCA children with and without EHD, and (2) to test the associations between EHD and several biological/physiological parameters. Nine of 51 SCA children (18%) at steady state (mean age 11.9 ± 3.8 years) exhibited EHD at the end of the 6MWT. The rate of perceived exertion increased with exercise in the two groups, but reached higher values in the EHD group. Heart rate and performance during the 6MWT did not differ between the two groups. The magnitude of change in SpO2 during the 6MWT was independently associated with the red blood cell (RBC) deformability and RBC aggregates strength. This study demonstrates that SCA children with EHD during a 6MWT have a higher rate of perceived exertion than non-EHD children despite a similar physiological demand, and that abnormal RBC rheology determinants appear to be significant contributors.

Comparison of clinical performance of i-gel with LMA-proseal in elective surgeries: A prospective randomized study

Background: Day-care surgery that is, the patient being discharged from the hospital on the same day of surgical procedure, has become immensely popular modality of treatment throughout the globe. Supraglottic airway devices are used commonly as an alternative to endotracheal intubation for delivering general anaesthesia in Day Care Surgery. I-gel is a type of Supraglottic device possessing a soft gel like, cuffless supraglottic airway made of thermoplastic elastomer. The Proseal LMA (PLMA), another supraglottic device was designed in late 1990’s especially for use with positive pressure ventilation at high pressures. The present study work is to record the time taken for successful insertion, number of insertion attempts, the quality of ventilation during anaesthesia, hemodynamic parameters (heart rate & Blood Pressure) and change in SpO2 and incidence of airway trauma and gastric distension with I-gel and Proseal LMA. Material and Methods: Sixty patients undergoing elective surgery under general anaesthesia were divided into two groups of 30 each. Group I in which anaesthesia was delivered using I-gel and in Group P, anaesthesia was delivered using Proseal LMA. Time taken for successful placement, number of insertion attempts, the quality of ventilation, hemodynamic parameters and incidence of airway trauma and gastric distension are recorded. Results: PLMA takes longer to insert with less hemodynamic stability than I-gel however the quality of airway seal achieved is comparable to that of I-gel. Conclusion: The present study showed that I-gel could be an effective and better alternative than Proseal LMA as a supraglottic airway device.

Quantitative analysis of the effect of fraction of inspired oxygen on peripheral oxygen saturation in healthy volunteers.

BackgroundThe international organization for standardization (ISO) 80601-2-61 dictates that the accuracy of a pulse oximeter should be assessed by a controlled desaturation study. We aimed to characterize the relationship between the fraction of inspired oxygen (FiO2) and peripheral oxygen saturation (SpO2) using a turnover model by retrospectively analyzing the data obtained from previous controlled desaturation studies.Materials and MethodsEach volunteer was placed in a semi-Fowler's position and connected to a breathing circuit to administer the hypoxic gas mixture containing medical air, oxygen, nitrogen, and carbon dioxide. Volunteers were exposed to various levels of induced hypoxia over 70–100% arterial oxygen saturation (SaO2). The study period consisted of two rounds of hypoxia and the volunteers were maintained in room air between each round. FiO2 and SpO2 were recorded continuously during the study period. A population pharmacodynamic analysis was performed with the NONMEM VII level 4 (ICON Development Solutions, Ellicott City, MD, USA).ResultsIn total, 2899 SpO2 data points obtained from 20 volunteers were used to determine the pharmacodynamic characteristics. The pharmacodynamic parameters were as follows: kout = 0.942 1/min, Imax = 0.802, IC50 = 85.3%, γ = 27.3.ConclusionThe changes in SpO2 due to decreases in FiO2 well explained by the turnover model with inhibitory function as a sigmoidal model.

An alternative and novel usage for ultrasound-guided erector spinae plane block: Extracorporeal shock wave lithotripsy in a paediatric patient.

Sir, Erector spinae plane block is a novel paraspinal interfascial plane block.[1] It has been performed for several indications, and its usage for paediatric patients have been increased recently.[23] It may be used safely especially in paediatric analgesia management instead of central neuroaxial techniques because of its distance to the important anatomical structures.[23] Herein, we would like to share our experience using erector spinae plane block (ESPB) for management of interventional pain during extracorporeal shock wave lithotripsy (ESWL) in a 2-year-old paediatric patient. Written informed consent for the procedure and future publishing were obtained from parents of patient. Two-year-old boy was scheduled to undergo ESWL due to multiple renal stones. The patient was taken to the ESWL unit. Midazolam (0.1 mg·kg−1) and propofol (1 mg·kg−1) was administered IV for sedation. The patient was placed in the right lateral decubitus position. Under aseptic conditions; ultrasound-guided ESPB was performed from the level of the Th10 with a high frequency, sterile sheath covered, 12 MHz linear US probe. Following the visualisation of the erector spinae muscle above the transverse process, 22G, 50 mm block needle was inserted in a cranial-caudal direction using the in-plane technique into the deep fascia. 6 ml of 0.25% bupivacaine was injected into the interfacial area[2] [Figure 1]. ESWL was commenced 10 minutes after the block. There were no changes in arterial pressure, heart rate, respiratory rate, and SpO2 during ESWL. No additional analgesic drug or sedation was performed to the patient during the procedure. The patient was immobile during ESWL. Patient was comfortable at the postoperative period and started to walk 1 hour after the ESWL.Figure 1: (a) Sonographic anatomy of the block (b) Needle direction and spread of local anaesthetic. LA indicates local anaesthetic (c) Patient position and probe localisation during ESPB performingAnaesthesia and analgesia management is a very important issue during ESWL. ESWL is a daycare procedure, patients usually are discharged in the same day. Effective opioid-free techniques may be used for post-procedural pain management.[4] The patient should be immobile during the procedure, and the sedation should be light for protection of the spontaneous respiration. So, regimens such opioid-free anaesthesia may be preferred. QLB block may be performed in paediatric patients for abdominal procedures like ESWL analgesia and provides at Th7-L1 dermatomes.[4] However, there have been some reports of complications related to QLB. QLB is administered in closer proximity to the intra-abdominal solid organs such as liver and kidney. Ahiskalioglu et al. reported the visualisation of hepatomegaly during the QLB block.[5] If this block is performed in less skilled hands, a number of complications such as solid organ injury may occur during block application. ESPB is a novel block defined for use in both acute and chronic pain and sometimes as the main anaesthesia method in both paediatric and adult patients.[123] ESPB is performed distant to solid organs and vascular structures. The transverse process is a natural anatomical barrier in front of the needle and visualisation is simpler under ultrasound guidance, so it may be performed safely.[12] To conclude, ESPB may provide effective interventional analgesia during paediatric ESWL safely for opioid-free analgesia treatment. Declaration of patient consent The authors certify that they have obtained all appropriate parent consent forms. In the form the parent(s) has/have given his/her/their consent for his/her/their child's images and other clinical information to be reported in the journal. The parents understand that the name and initials of their child will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Arterial hypertension with comorbid chronic obstructive pulmonary disease: relationship between tolerance to physical exercise and structural and functional state of the heart.

The aim of the study was to establish the relationship between tolerance to exercise, oxygen saturation, and structural and functional cardiac status in patients with hypertension in combination with COPD. This study included 120 patients with primary arterial hypertension of stage I-II, grade 1, 2, and 3 in combination with COPD of grades 2 and 3 and clinical groups A, B, C, D, consisting group 1; group 2 – 30 patients with primary hypertension, and group 3 – 30 patients with COPD; group 4 – 30 practically healthy people representative by age and sex. Research methods included general clinical examination (collection of complaints, anamnestic data) and instrumental research methods: electrocardiography (ECG), echocardiography, measurement of ambulatory blood pressure (BP) profile (ABPM), spirometry, pulsoxymetry (SpO2), 6-minutes walking test (6MWT). On examination of 120 patients with stage I-II, grade 1 hypertension was established in 19 (15.8%), grade 2 was in 83 (69.2%) and grade 3 was in 18 (15%) patients, respectively. COPD in clinical group A was diagnosed in 10 (8.3%), B – in 51 (42.5%), C – in 18 (15%) and D - in 41 (34.2%) patients, respectively. The most common was AH stage 2 with COPD in clinical group B – 35 (29.2%) cases and D – 31 (25.8%) cases. The 24-hour average systolic BP (SBP) in patients of the main group was 165 [144;178] mmHg, and the diastolic BP (DBP) was 103 [94;111] mmHg. The daytime average SBP was 160 [140;180] mmHg, and the DBP was 105 [93;117] mmHg accordingly. The night-time average SBP was 165 [155;175] mmHg, DBP – 100 [95;105] mmHg, heart rate (HR) – 83 [76;88] minutes, respiration rate (RR) – 21 [19;24] minutes. Decreases in index of chronotropic reserve (ICR) and the index of inotropic reserve (IIR) and load index indicate an increase in myocardial oxygen demand during exercise. There was an inverse correlation of IIR with SBP at rest (r= –0.42; p˂0.05) and a direct correlation with age (r=0.28; p˂0.05), which is significantly different from the control group. A direct correlation was found between the double product (DP) before and after exercise (r=0.43; p˂0.05), which indicated an increase in consumption of oxygen by the myocardium. We found a direct correlation between left atrium (LA) and the ratio of expiratory volume per 1 sec (FEV1) to the forced lung capacity (FEV) – FEV1/FVC (r=0.32; p˂0.05), which indicates the effect of the severity of bronchial obstruction on the level of left ventricular (LV) overload in patients with hypertension combined with COPD. The inverse correlation between thickness of the posterior wall of the LV (RVWT) and FEV1/FVC (r= -0.32; p˂0.05) indicates the contribution of disorders of bronchial patency and intrathoracic pressure with the level of BP to the development of concentric remodeling and LV hypertrophy. The inverse correlation between SV and COPD Assessment Test (CAT) (r= -0.32; p˂0.05) indicates an additional effect of COPD clinical severity on central hemodynamics in patients with hypertension. This relationship between the ventilatory and hemodynamic parameters is confirmed by the inverse correlation of HR and FVC (r= –0.33; p˂0.05)), left ventricular internal dimension (LVEDD) of LV and CAT (r= –0.24; p˂0.05)), stroke volume (SV) and Modified British Medical Research Questionnaire (mMRC) (r= –0.42; p.00.05), CAT and pack years (r=0.33; p˂0.05), inverse correlation between CAT and mMRC and FEV1, FVC and FEV1/FVC (r= -0.40;p˂0.05 and r= -0.45; p˂0.05), respectively. Linear regression analysis showed that changes in SV LV, LVEDD and SpO2 were dependent predictors of patient’s worsening state according to CAT (p˂0.05). The direct correlation was established between the desaturation (ΔSpO2) and ΔDP (r=0.48) and the inverse of ΔSBP (r= -0.29), 6MWT (r= -0.45), ICR (r= -0.34) and IIR (r= -0.29), which indicates a pronounced effect of hypoxemia on hemo­dynamics in patients with hypertension in combination with COPD. Comprehensive determination of cardiorespiratory reserve by 6-minute walk test, pulse oximetry and ambulatory blood pressure monitoring in patients with hypertension in combination with COPD makes it possible to establish disadaptation of the body to physical activity due to hypoxemia, decrease in the index of chrono- and inotropic reserves, which is an indication for administering appro­priate therapy. In patients with hypertension combined with COPD, the degree of desaturation, stroke volume, end-diastolic parameters of the left ventricle, maximal size and volume of the left atrium, as well as remodeling of the left heart sections in the concentric direction can be considered as independent predictors of prognosis. The 6-minute walk test with desaturation can be used as an additional method of personalizing rehabilitation measures in patients with hypertension in combination with COPD.

Appraisal of the ‘penumbra effect’ using lingual pulse oximetry in anaesthetized dogs and cats

ObjectiveFactors described as contributors to the ‘penumbra effect’ in relation to pulse oximetry include optical shunting, circulatory anastomoses and probe parallelity. This study aimed to clarify the main underlying mechanism involved. Study designProspective clinical trial. AnimalsA total of 30 dogs and 15 cats (client-owned). MethodsIn anaesthetized dogs and cats, a pulse oximeter probe was placed on the tongue to measure haemoglobin oxygen saturation (SpO2) and perfusion index. In 15 dogs, the probe was positioned at the root (baseline) of the tongue, then at 0.5 and 1 cm rostral to it, to investigate the effect of circulatory anastomoses on SpO2 values. In cats (which do not have lingual arteriovenous anastomoses), the probe was positioned at the root and apex of the tongue. To assess the effect of probe parallelity on SpO2 values in dogs, two lines were drawn parallel to the planes of the light-emitting diode and the detector surfaces and the intersection angle calculated using ImageMeter Pro, Google Play. In a further 15 dogs, the probe was placed at the tongue edge (0% optical shunt), with 50% optical shunt, then with the 50% optical shunt shielded. Data were analysed using Friedman’s test, Student t test and Pearson’s correlation coefficient (p < 0.05). ResultsIn dogs, SpO2 values were significantly higher at 1.0 cm than at baseline (p < 0.0001). In cats, there were no significant differences in SpO2 values at each location. There was no significant difference in SpO2 between 0% and 50% optical shunt in dogs. SpO2 had a moderate negative correlation with tongue thickness and negligible correlation with intersection angle. Conclusions and Clinical relevanceCirculatory anastomoses are probably responsible for observed changes in SpO2 as the probe is placed towards an extremity, rather than optical shunting or probe parallelity.

Pulse Oximetry.

Pulse Oximetry.

P4675The utility of additional balloon pulmonary angioplasty for residual hypoxemia in normohemodynamic chronic thromboembolic pulmonary hypertension patients after invasive treatments

Abstract Background Balloon pulmonary angioplasty (BPA) improves hemodynamics, symptoms and exercise capacity in patients with chronic thromboembolic pulmonary hypertension (CTEPH) who are ineligible for pulmonary endarterectomy (PEA). However, certain patients still have hypoxemia after BPA or PEA despite normalization of hemodynamics. In CTEPH, hypoxemia is related increased dead space ventilation caused by vascular obstruction. Purpose This study was aimed to clarify whether additional BPA can improve hypoxemia of CTEPH patients after normalization of hemodynamics. Methods A total of 335 patients who underwent initial series of BPA in our institute were followed up. Sixty-four patients with mean pulmonary artery pressure (mPAP) &lt;30mmHg and percutaneous oxygen saturation (SpO2) &lt;95% without oxygen inhalation at more than 6 months after the initial series of BPA and of patients who could reevaluate hemodynamics and oxygenation after additional BPA were enrolled. These patients were divided into two groups with or without additional BPA procedures. Change of hemodynamics and SpO2 were retrospectively investigated. Results Thirty-three of 64 patients underwent additional BPA procedures. Patients' age was older in BPA group than those in non-BPA group (71.3±10.4 vs. 66.5±9.4 years old, p=0.02). mPAP and pulmonary vascular resistance (PVR) was significantly higher in BPA group (mPAP: 23.9±3.2 vs. 20.7±3.8 mmHg, p=0.001, PVR: 4.2±1.2 vs. 3.5±1.4 wood unit, p=0.03, respectively). Among the 1.8±1.4 BPA procedures per person, total 6.6±3.8 segmental pulmonary arteries per person were treated. While no obvious improvements were observed in non-BPA group, PVR and SpO2 in BPA group were significantly improved (4.2±1.2 to 3.7±1.3 wood unit, p=0.002, 90.7±3.1% to 94.1±3.6%, p&lt;0.001, respectively). In the multivariate logistic regression analysis, additional BPA procedures were associated with further improvement of SpO2 (hazard ratio, 3.7; 95% confidence interval, 1.2–11.5; P=0.02). Conclusions Additional BPA procedure was associated with improvement of hypoxemia in CTEPH patients after normalization of hemodynamics. Treating as many lesions as possible in BPA might relieve the patients' residual dyspnea.

Decrease in Cerebral Oxygen Saturation During the 6-Minute Walk Test in Pediatric Pulmonary Arterial Hypertension.

This observational study aimed to investigate the relationship between regional cerebral oxygen saturation (rSO2) during the 6-minute walk test (6-MWT) and the demographic/clinical features of patients with pulmonary arterial hypertension (PAH). Cerebral oxygenation was evaluated during the 6-MWT in 20 pediatric patients with PAH aged ≥ 7years [13 male, 7 female; median age 12.25 (range 7-18) years]. In all patients, regional cerebral oxygen saturation (rSO2), arterial oxygen saturation (SpO2), and heart rate (HR) were measured using near-infrared spectroscopy (NIRS) for 2min before the test, during the 6-MWT test, and 2min after the test. The relationship between the changes in rSO2, heart rate, and SpO2 values and clinical and laboratory features was compared statistically. The mean pulmonary arterial pressure (mPAP) was 77 (range 25-126) mmHg, and the median 6-minute walk distance (6-MWD) was 427.5 (300-570) m. The changes in rSO2 measurements ranged between 3.41 and 21.8%, and 70% of the patients had a greater than 10% decrease in rSO2 during the test compared with baseline. Eight patients showed a decrease in rSO2 without SpO2 changes. The present study demonstrated a significant decrease in cerebral oxygenation in pediatric patients with PAH during the 6-MWT. We hypothesized that using a combination of the 6-MWT and regional cerebral oxygenation monitoring in pediatric patients with PAH in order to evaluate exercise capacity, as a reflection of reduced daily activities, would provide more precise predictive values than the 6-MWT alone.

Preliminary Effectiveness and Safety of High Frequency Oscillation in Addition to Mechanical Insufflation and Exsufflation for Intratracheal Mucus Removal in Patients With Neuromuscular Disease: Protocol for a Prospective Study.

BackgroundMechanical insufflation-exsufflation (MI-E) is necessary for noninvasive management of respiratory clearance in patients with neuromuscular disorders (NMDs). Its utility has been proven, and the technique is recommended in a number of international guidelines for the management of patients with NMDs. However, the clearance of thick secretions adhering to the tracheobronchial walls could be problematic when these patients suffer from respiratory tract infections. To improve the effectiveness of the noninvasive technique, a novel device combining MI-E with high frequency oscillation (HFO) has been developed. However, the efficacy of HFO therapy in NMDs has not been well studied.ObjectiveThe aim of this study was to elucidate the effect of MI-E combined with HFO for mucus removal in NMD patients. To evaluate its efficacy, changes in transcutaneous oxygen saturation (SpO2), which may predict intratracheal mucus removal, will be measured before and after use of MI-E.MethodsThis is a single-center, nonblinded, nonrandomized prospective study that will enroll 5 subjects hospitalized in Kobe University Hospital owing to respiratory tract infection. All subjects will receive MI-E therapy a few times daily and will receive HFO every other day, for 6 days. Before and after MI-E use, SpO2 will be obtained and the change in SpO2 (ΔSpO2) between MI-E with and without HFO will be calculated. For every subject, the average of ΔSpO2 with or without HFO will be obtained and the null hypothesis that there is a mean change of 0 in the SpO2 between MI-E with and without HFO will be tested using the paired t test. If the treatment with HFO is found to be statistically significantly superior to the treatment without HFO, the study will conclude that HFO addition is more efficacious than no HFO addition.ResultsA total of 2 subjects have already been recruited and enrolled in this study as of August 2018.ConclusionsThis unique protocol will assess the efficacy of adding HFO to MI-E during the acute phase of respiratory tract infection in patients with NMDs.International Registered Report Identifier (IRRID)DERR1-10.2196/12102

Sex Differences In Respiratory And Circulatory Cost And Arterial Oxygen Saturation During Hypoxic Walking

PURPOSE: Since women have smaller lungs and a decreased capacity for lung diffusion compared to men, these differences may increase the work required for women to maintain a given rate of pulmonary ventilation (VE), resulting in greater exercise-induced arterial hypoxemia (EIAH). Previous studies have ignored the energy expenditure (EE) on circulation (i.e., heart rate; HR) and ventilation during exercise. METHODS: We sought to investigate sex differences in EE, VE and HR in response to changes in SpO2. We hypothesized that women would experience greater EIAH, and that the contribution rate of EE, VE, and HR in response to changes in SpO2 would be different between the sexes. We measured EE during walking on a level gradient under normoxia (room air, 21% O2), and moderate hypoxia (13% O2). Ten healthy young men and ten healthy young women walked on a treadmill at seven speeds (0.67-1.67 m s-1). Each walking speed lasted for four minutes. EE was calculated using pulmonary oxygen uptake and carbon dioxide output. RESULTS: During walking, reductions in SpO2 trended slightly greater in women under hypoxia (71.5 ± 4.5 % for men and 67.7 ± 6.1 % for women at the fastest gait speed, P > 0.05). Hypoxia-induced elevation in EE, HR, and VE were calculated by the difference between values in hypoxia and normoxia. Using a multivariate model that combined EE, VE, and HR to predict ΔSpO2 (hypoxia-induced reduction), we obtained a very strong fit model both for men (r2 = 0.900, P < 0.001) and for women (r2 = 0.957, P < 0.001). We also tried to estimate the relative contributions of ΔEE, ΔVE, and ΔHR to predict ΔSpO2 by using standard partial regression coefficients. The contribution rate to predict ΔSpO2 was markedly different between men and women. In women, the effect of ΔEE and ΔVE were greater (EE: 28.1% in women vs. 15.8% in men; VE: 4.1% in women vs. 1.7% in men). Conversely, in men the contribution of ΔHR was greater (82.5 % in men and 67.9 % in women). Moreover, significant sex differences in breathing frequency and tidal volume were observed (P < 0.05, respectively). CONCLUSIONS: These findings suggested that high-altitude adaptation in response to hypoxemia has different underlying mechanisms between men and women. Our results can help to explain how men and women adapt high-altitude environments.