A Comparison and Validation of Predicted Continuous Positive Airway Pressure Formulas vs Autotitration

Background: Continuous positive airway pressure (CPAP) is the treatment of obstructive sleep apnea (OSA). The CPAP pressure is generally estimated by manual titration or an auto-CPAP device. An alternative method involves the use of the predictive equation. There is limited study available for the Indian population. Objectives: To compare CPAP pressure obtained by mathematical formulas with auto-CPAP titration and formulation, a preliminary predictive equation from derived data to be validated with titrated CPAP. Methods and materials: A retrospective observational study was performed in 130 patients in Department of Pulmonary Medicine of our institute from April 2019 to July 2021. Detailed history, anthropometric parameters, whole-night level-II polysomnography (PSG), and CPAP titration were performed. Stepwise linear regression was applied to establish predictive equation. This equation results were compared with available other equations and autotitrated readings. Results: The mean (SD) of age, BMI, neck girth, Epworth score, lowest SPO2 (%), and AHI was 56.72 (11.31), 33.87 (6.43), 39.7 (4.46), 17.75 (3.18), 84.65 (8.44), and 48.75 (21.09), respectively, with male杅emale ratio of 3:2. Mild, moderate, and severe OSA were 7 (5.4%), 18 (13.8%), and 105 (80.8%), respectively. Continuous positive airway pressure obtained from equations was in the range of 7.40�.95 cm H2O. Obtained readings by equations showed a comparable correlation with CPAP-titrated results (p <0.001). Conclusion: The optimum titration pressure correlates with pressure derived from the predictive equation that is predicted average therapeutic CPAP pressure = 3.98 + 0.065 (ODI) + (AHI) + 0.018 (nadir SPO2) - 0.013 (NC).

Adaptação cardiovascular no Teste de Caminhada dos Seis Minutos em pacientes com DPOC: estudo transversal / Cardiovascular adaptation in the six-minute walk test in COPD patients: transversal study

OBJETIVO: Avaliar o comportamento da adaptação cardiovascular e da saturação periférica de oxigênio em indivíduos com DPOC submetidos no teste de caminhada dos seis minutos (TC6). MATERIAL E MÉTODOS: Trata-se de um estudo de corte transversal, que foram incluídas pessoas com diagnóstico de DPOC, confirmado pela espirometria e de ambos os sexos. A magnitude de sintomas foi avaliada pela escala de dispneia Medical Research Council (MRC) e questionário COPD Assessment Test (CAT). Aplicou-se o TC6 para avaliar a tolerância ao esforço. Para mensurar a frequência cardíaca máxima (FC máx) prevista para a idade foram utilizadas equações específicas para população brasileira. RESULTADOS: Avaliou-se 34 indivíduos com DPOC, 20 (58,8%) homens; relação VEF1/CVF foi 56,7%± 10,2% pós broncodilatador (BD). Quatorze 14 (41,2%) indivíduos apresentaram impacto clínico moderado; 16 (47,2%) dos avaliados apresentou grau 2 na escala do MRC. As médias das distâncias percorridas no primeiro e segundo TC6 foram 383,5 ± 13,6; 408,6 ± 85,7 metros, correspondendo a 70, 75%; 75,10% em relação ao valor previsto (p=0,001). As médias da FC máx ao final do primeiro e segundo TC6, foram 94,1 ± 21,9; 92,3 ± 17,9 bpm e a FC pós percentual da FC máx prevista pré e pós TC6 foram 61,1% ± 17,7%; 59,7% ± 21,5% e 14 (41,2%) pacientes apresentaram dessaturação de O2 no primeiro TC6; 9 (26,5%) no segundo teste. CONCLUSÕES: Pacientes com DPOC, apresentam aumento da FC identificado pelo esforço submáximo, por meio do percentual da FC max. Indivíduos com maior comprometimento da função pulmonar apresentaram dessaturação de O2. .

OBJECTIVE: To evaluate the behavior of cardiovascular adaptation and peripheral oxygen saturation in individuals with COPD submitted to the six-minute walk test (6MWT). MATERIAL AND METHODS: It was performed a descriptive study with person with a diagnosis of COPD confirmed by spirometry of both sexes. The Medical Research Council (MRC) dyspnea scale and the COPD Assessment Test (CAT) questionnaire were used to assess the magnitude of symptoms. The 6MWT was used to assess effort tolerance. To measure the maximum heart rate (HRmax) predicted for age, specific equations were used for the Brazilian population. RESULTS: 34 individuals with COPD were evaluated, 20 (58.8%) men; FEV1 / FVC ratio was 56.7% ± 10.2% after BD. Fourteen (41.2%) were classified as grade 2 and were classified as grade 2 (MRC scale). The means of the distances covered in the first and second TC6 were 383.5 ± 13.6; 408.6 ± 85.7 meters, corresponding to 70.7%; 75.1% in relation to the predicted value (p = 0.001). The mean maximum heart rate at the end of the first and second 6MWT were 94.1 ± 21.9; 92.3 ± 17.9 bpm and the heart rate post-percentage of the predicted maximum heart rate before and after the 6MWT were 61.1% ± 17.7%; 59.7% ± 21.5% and 14 (41.2%) patients presented O2 desaturation on the 6MWT; 9 (26.5%) in the second test. CONCLUSIONS: Patients with COPD throughout the 6MWT show increased heart rate and O2 desaturation in exercise activity.

Risk factors of oxygen saturation decrease during intrahospital transportation of intensive care unit patients in emergency department / 中华护理杂志

Objective To explore risk factors of oxygen saturation (SpO2) decrease during intrahospital transporta-tion (IHT) of intensive care unit (ICU) patients in emergency department,and provide theoretical basis for prevent-ing oxygen saturation decrease during intrahospital transportation. Methods A cross-sectional study design was adopted,from April to May,2017,we investigated 182 ICU patients who required IHT in an emergency department in a tertiary hospital in Shanxi Province by using self-designed Evaluation Form of Intrahospital Transportation for ICU Patients in Emergency Room. We divided patients into two groups based on whether their SpO2 decreased or not. Risk factors of SpO2 decrease were identified by univariate and multivariate Logistic regression analysis. Results Among 182 patients,117 had SpO2 decrease,and the rate of SpO2 decrease was 64.3%. Patient's age,MEWS score, disease type,escort personnel,and oxygen supply device were risk factors of SpO2 decrease. Conclusion SpO2 de-crease is the result of combination of multiple risk factors during IHT. We ought to enhance training of escort person-nel,assess patient's condition and SpO2 level accurately and make plan before transportation,choose qualified oxygen supply device to ensure patients can have effective oxygen supply during IHT,which prevent SpO2 decrease during IHT.

Change of AHI and ODI in OSAHS patients with different sleep body positions / 中国耳鼻咽喉头颈外科

[ABSTRACT]OBJECTIVETo assess the sleep body position's effects on AHI and ODI during sleep in obstructive sleep apnea hypopnea syndrome (OSAHS) patients with different severity.METHODSThe clinical data of 113 subjects who had been diagnosed OSAHS or normal by polysomnography (PSG) between 2013 and 2014 in our department were retrospectively studied. They were divided into normal control group (AHI30/h, 40 patients). PSG data of AHI and ODI in different body position in each group were further analyzed.RESULTSIn normal group, The AHI and ODI in supine position were significantly higher than that in the left or right lateral position, and the difference between the left and right lateral position was not significant. In the mild to moderate OSAHS group, the AHI and ODI in supine were higher than that in the left lateral position slightly, while the data in supine was higher than that in the right lateral position significantly. In the severe group, the data between the supine and the left lateral position was not statistically different, while the supine position data was higher compared with that of the right lateral position. CONCLUSIONAHI and ODI were higher in supine position than that in lateral position, while the AHI and ODI in right lateral position is higher than that in left lateral position in OSAHS patients with different severity. The ODI and AHI are consistent in reflecting the severity of the OSAHS.

The incidence of oxygen desaturation during rapid sequence induction and intubation / 世界急诊医学杂志（英文）

@#BACKGROUND: Rapid sequence induction and intubation (RSII) is an emergency airway management technique for patients with a risk of pulmonary aspiration. It involves preoxygenation, administration of predetermined doses of induction and paralytic drugs, avoidance of mask ventilation, and laryngoscopy followed by tracheal intubation and keeping cricoid pressure applied till endotracheal tube cuff be inflated. Oxygen desaturation has been seen during RSII. We assessed the incidence of oxygen desaturation during RSII. METHODS: An institution-based observational study was conducted from March 3 to May 4, 2014 in our hospital. All patients who were operated upon under general anesthesia with RSII during the study period were included. A checklist was prepared for data collection. RESULTS: A total of 153 patients were included in this study with a response rate of 91.6%. Appropriate drugs for RSII, equipments for RSII, equipments for difficult intubation, suction machine with a catheter, a monitor and an oxygen backup such as ambu bag were not prepared for 41 (26.8%), 50 (32.7%), 51 (33.3%), 38 (24.8%) and 25 (16.3%) patients respectively. Cricoid pressure was not applied at all for 17 (11.1%) patients and 53 (34.6%) patients were ventilated after induction of anesthesia but before intubation and endotracheal cuff inflation. A total of 55 (35.9%) patients desaturated during RSII (SPO2<95%). The minimum, maximum and mean oxygen desaturations were 26%, 94% and 70.9% respectively. The oxygen desaturation was in the range of <50%, 50%–64%, 65%–74%, 75%–84%, 85%–89 % and 90%–94% for 6 (3.9%), 7 (4.6%), 5 (3.3%), 10 (6.5%), 13 (8.5%) and 14 (9.2%) patients respectively. CONCLUSION: The incidence of oxygen desaturation during RSII was high in our hospital. Preoperative patient optimization and training about the techniques of RSII should be emphasized.

Oxygen Desaturation during Nutritive Sucking in Premature Infants with Bronchopulmonary Dysplasia: Its Effect on Feeding and Growth until 4 Months of Corrected Age

PURPOSE: This study examined the occurrence of oxygen desaturation events during nutritive sucking in premature infants with bronchopulmonary dysplasia (BPD) and its effects on feeding and growth outcomes until 4 months of corrected age (CA). METHODS: Thirty-four premature infants with BPD free from major cardiac, gastrointestinal, respiratory anomalies were included. By reviewing medical records, clinical characteristics, feeding conditions at 36 weeks of postmenstrual age (PMA), we focused on oxygen desaturation, and short-term outcomes in 14 infants with no or mild desaturation (group A) and in 20 infants with moderate or severe desaturation (group B). RESULTS: Group B had lower birth weight and shorter gestational age at birth, longer duration of hospitalization, was discharged at higher weeks of PMA, and needed ventilatory assist and oxygen supplementation longer than group A (P<0.05). Group B started nutritive sucking later, with a greater decrease in SpO2 during sucking, being more indicative of feeding problems at 40 weeks of PMA, but not at 4 months of CA. Percent of infant needing oxygen supplementation and percent of infants with growth failure were not different between groups at 40 weeks of PMA and 4 months of CA. Body weight and growth velocity differences noted at 40 weeks of PMA became insignificant at 4 months of CA. CONCLUSION: The severity of desaturation during nutritive sucking in premature infants with BPD influenced the infant's feeding and growth at 40 weeks of PMA. However, it disappeared at 4 months of CA.

Is Obstructive Sleep Apnea a Risk Factor of Subclinical White Matter Damages?

BACKGROUND: Obstructive sleep apnea (OSA) has been reported to increase risk of ischemic stroke. This study was performed to investigate the prevalence and relationship of subclinical white matter damages (SD) in patients with OSA. METHODS: All subjects (n = 54) had brain MRI and nocturnal polysomnogram (PSG). SD are defined by nonsymptomatic lacunar infarcts > 3 mm or periventricular white matter changes (PVWC). We analyzed the difference between OSA patients with and without SD (SD and non-SD groups), and also with and without PVWC. Using apnea-hypopnea index (AHI), we classified OSA into mild (515). RESULTS: SD group (n = 31) showed significantly increased apnea-hypopnea index (AHI), apnea index (AI) and oxygen desaturation index (ODI) compared to non-SD (n = 23). Among the 37 patients without lacunar infarctions, 14 showed PVWC while the other 23 did not have any lesions. Compared to non-SD group, SD group showed increased AHI and ODI, and decreased lowest SaO2 (p < 0.05). Similarly, AHI and ODI were higher and the lowest SaO2 was lower in patients with PVWC than without PVWC (p < 0.05). Moderate to severe OSA group showed more frequent subclinical or periventricular white matter changes than mild group (p < 0.05). CONCLUSIONS: Severity of OSA showed a positive correlation with the occurrence of subclinical white matter damages. OSA may cause subclinical white matter damages.

The Resting and Exercise Related Oxygen Desaturation as The Associated Factor for Sleep Related Oxygen Desaturation in Patients with Chronic Obstructive Pulmonary Disease / 결핵

BACKGROUND: Nocturnal hypoxemia occurs in patients with chronic obstructive pulmonary disease(COPD) and the detection and treatment of nocturnal hypoxemia should be part of the management of COPD patients. We performed this study to evaluate the factors influencing to sleep related arterial oxygen desaturation(SaO2) in patients with COPD. METHODS: Resting and exercise cardiopulmonary function test, polysomnography, and SaO2 during resting, exercise and sleep were measured in 12 patients with COPD. RESULTS: The SaO2 fell twice as much during sleep as during maximal exercise(13.1 9.3% fall in nocturnal SaO2 vs. 6.4 3.3%, p<0.05). Fall in nocturnal SaO2 was well correlated with mean exercise SaO2(r=-0.78, p<0.05), minimum exercise SaO2(r=-0.90, p<0.01), and resting SaO2(r=-0.82, p<0.05). Lowest sleep SaO2 was well correlated with mean exercise SaO2(r=0.80, p<0.05), lowest exercise SaO2(r=0.90, p<0.01), and resting SaO2(r=0.84, p<0.05). CONCLUSION: Resting and exercise SaO2 was well correlated with nocturnal SaO2, but exercise study add no additional information to predicting the nocturnal oxygen desaturation in patients with COPD.

Arterial Oxygen Desaturation after Salbutamol Nebulization in Wheezy Infants and Children

PURPOSE: Nebulized selective beta2-adrenoreceptor agonists have been widely used in acute asthma and selectively in acute bronchiolitis. However, nebulized salbutamol have been reported to cause arterial oxygen desaturation in some of the acute bronchiolitis and severe asthma patients. This may be the results of a paradoxical bronchoconstriction linked to acidic and hyper-osmolar nebulized salbutamol solution and etc. We assessed the changes in arterial oxygen saturation by percutaneous pulse oxymeter during and after nebulization of salbutamol solution and compared the effect of 100% oxygen with the compressed air as a driving gas. METHODS: This study was performed in 80 mild to moderate wheezy children(bronchiolitis 51, asthma 29) who were admitted to Pediatrics department of of EWHA from January 1992 to October 1993. The study children are randomly assigned to be nebulized by compressed air or 6l/min of 100% oxygen as a driving gas. The arterial oxygen saturation, wheeze score, retraction score, and heart rate were recorded before nebulization, post-nebulization, 5, 10, 15 and 30minutes. RESULTS: 1) Arterial oxygen saturation decreased significantly at post-nebulization five minutes only in bronchiolitis, treated with salbutamol nebulization without oxygen(p0.05). 2) Wheeze score decreased significantly at post-nebulization 5-30minutes in asthma but not in bronchiolitis whether nebulized salbutamol with or without oxygen(p0.05). CONCLUSIONS: Significant fall in arterial oxygen saturation was noted only in bronchiolitis treated with salbutamol nebulization without oxygen. In bronchiolitis, oxygen (6l/min) is better than compressed air as a driving gas during salbutamol nebulization to prevent hypoxemia.

Arterial Oxygen Desaturation during Non-sedated Diagnostic Gastrointestinal Endoscopy / 대한소화기내시경학회지

We studied arterial oxygen desaturation, using a pulse oximeter, in 132 patients undergoing diagnostic upper gastrointestinal endoscopy to obtain predictive factors of the change. The baseline arterial oxygen saturation (SaO2) level was 98.8+/- 1.2%. During the procedure, oxygen desaturation (SaO2>95%) was found in 90.2% of the patients, Mild oxygen desaturation (95>SaO2>90%) was found in 9.8% of the patients, and there was no severe oxygen desaturation(SaO2<90%). Age(P=0.52), gender(P =0.48), smoking(P =0.71), body mass index(P =0.32), and endoscopy time(P = 0.68) was not related to the degree of oxygen desaturation. These results suggest that oxygen desaturation, which may rarely induce serious cardiopulmonary events, is not frequently observed during non-sedated diagnostic upper endoscopy.

The effect of maximal interval training for 10 weeks on arterial oxygen saturation during heavy exercise / 体力科学

The purpose of the present study was to investigate the effect of maximal interval training for 10 weeks on arterial oxygen saturation (SaO<SUB>2</SUB>) and ventilatory response during heavy exercise. Seven subjects volunteered for participation in the study. All subjects performed an interval training 4 days per week. Training protocol per day consisted of five periods of exercise of 3-min duration on a cycle ergometer at a power output on 100% maximal oxygen uptake (VO<SUB>2</SUB>max), interspersed with 2-min recovery cycle at 50%VO<SUB>2</SUB>max. VO<SUB>2</SUB>max and ventilatory data measured every week. SaO<SUB>2</SUB>, end-tidal oxygen partial pressure (PETO<SUB>2</SUB>), end-tidal carbon dioxide partial pressure (PETCO<SUB>2</SUB>) and the ventilatory equivalent for oxygen (VE/VO<SUB>2</SUB>) measured during 5-min heavy exercise at 90%VO<SUB>2</SUB>max every other week. VO<SUB>2</SUB>max significantly increased from 52.5±4.9 to 60.6±5.8 ml⋅ml<SUP>-1</SUP>⋅kg<SUP>-1</SUP> during the training. SaO<SUB>2</SUB> reduced significantly from 95.4±1.1 to 93.3±1.8%, similarly PETO<SUB>2</SUB> and VE/VO<SUB>2</SUB> reduced during the training. A significant positive correlation was found among SaO<SUB>2</SUB>, PETO<SUB>2</SUB> and VE/VO<SUB>2</SUB> during heavy exercise (SaO<SUB>2</SUB>-PETO<SUB>2</SUB>, r<SUP>2</SUP>=0.48, P<0.05 ; SaO<SUB>2</SUB>-VE/VO<SUB>2</SUB>, r<SUP>2</SUP>= 0.49, P<0.05; PETO<SUB>2</SUB> - VE/VO<SUB>2</SUB>, r<SUP>2</SUP>=0.81, P<0.05) . These results suggest that-50% of the arterial O<SUB>2</SUB> desaturation during heavy exercise can be accounted for by low ventilatory response. Therefore the maximal intervsal training induced arterial O<SUB>2</SUB> desaturation during heavy exercise, which can be half explained by low ventilatory response.

The Changes of Percutaneous Oxygen Saturation Following Obstructive Apnea in Infants / 대한마취과학회지

Preoxygenation is a standard anesthetic technique which prevents significant hypoxemia during the induction of anesthesia. Complete oxygenation is especially important in clinical situations of difficult intubation or in patients with decreased FRC, and in siturations where oxygen saturation is critical. During the induction of anesthesia in children, airway obstruction and apnea are associated with rapid development of hypoxemia. The decreasing speed of oxyhemoglobin saturation was faster in smaller infants than bigger infants. The most important factor determining the speed with which hypoxemia develops in healthy children is probably the oxygen reserve contained in the lungs and its relation to the oxygen consumption of the child. With deaeasing age, the arterial oxygen consumption increases and the ratio of FRC to body weight decreases. Due to the anatomical structure of an infant's upper airway, it is more difficult to obtaine patient airway in infants than in children. During repeated atttempts to intubate the trachea or while waiting for recovery from laryngeal spasms hypoxia can occur easily resulting in visible cyanosis in infants. This study was carried out to measure the time permissible for apnea before occurance of hypoxia following full oxygenation. The subjects consisted of 6 randomly selected infants 1-2 month of age, 4.6+/-0.6 Kg of body weight with no abnormalities of cardiorespiratory functions. After the intramuscular injection of atropine, patients were anesthetized through mask using oxygen and halothane. SpO2 and pulse rates were recorded throughout the study. After the patients were intubated, a plug was placed on the distal end of the tube to induce obstructive apnea. As soon as SpO2 decreased to just below 90%, the patients were ventilated again. In 2 of the infants, the time required to obtaine 90% saturation was 60 seconds. Within less than 70 seconds, four out of 6 infants had SpO2 below 90% and SpO2 below 80% were noticed in 3 cases. After the reestablishment of ventilation, SpO2 returned to the preapneic value within 10 second in all subjects. There was no evidence of increasing pulse rate as SpO2 levels decreased. However, pulse rate decreased in all subjects thoughout the study. In summary, maximum time permissible for apnea in neonate and young infant is approximately one minute. Furthermore, tachycardia should not be used as a sign for the onset of hypoxia.

Arterial Oxygen Desaturation Rate Following Obstructive Apnea in Parturients / 대한마취과학회지

Preoxygenation is a standard anesthetic technique for preventing a significant hypoxemia during the induction of anesthesia. Complete denitrogenation is especially important in clinical situations of difficult intubation or in patients with decreased functional residual capacity, and in situations where oxygen saturation is critical. Oxygen consumption in pregnancy is markedly increased at term as compaired to the nonpregnant stage. It is important to evaluate how long parturient women can withstand apneic hypoxemia during induction of general anesthesia. This study was carried out to measure the duration of time required to decrease the SaO2 to 90% After written informed consent was obtained from six healthy parturients who were to under go elective Cesarean section and six healthy non-pregnant women who were to have total abdominal hysterectomies. All subjects had a tight fitting anesthesia mask applied and breathed 100% oxygen, and a single isolated apnea was carried out. Arterial oxygen saturation and gas tensions were measured at a time SaO2 decreased to 90%, also blood gas data of 4 minutes after apnea in the non-pregnant women were obtained. From these, arterial oxyhemoglobin content was calculated, and mean desaturation rate from denitrogenation to the time SaO2 decreased to 90% was calculated. The mean time to obtain 90% saturation was 7.5+/-0.9 minutes in the nonpregnant women and 3.6+/-0.8 minutes in the parturient group. The mean slope of desaturation was steeper in the paturient(-3.336) than the nonpregnant (-1.52). The PaO2 inereased over 400mmHg in both the groups after denitrogenatio. After 4 minutes of apnea, the mean PaO2 decreased to 200mmHg in the non-pregnant women. The rate of rise of alveolar PCO2 during apnea were alower in the non-pregnant women(2.8+/-1.2mmHg/minute) than in the parturient women(6.8+/-1.8mmHg/minute). This study demonstrates that the rate of oxygen desaturation is faster in the parturients than the nonpregnant women. It is suggested that those results came out because of pregnancy-in-duced increase of oxygen consumption rate and decrease in FRC. The results of this study show the induction for term parturients should be speeded up with caution after full oxygenation in comparison with non-pregnant patients.