Simplified method for determination of the Oxygen Dissociation Curve (ODC) / Método simplificado para determinar la curva de disociación de oxígeno (cdo)

RESUMEN La afinidad de la hemoglobina (Hb) por oxigeno (O2) es un factor importante que influye en el transporte de este gas, especialmente en hipoxia y en diferentes enfermedades como anemia o fibrosis quística. En la medición de la afinidad se usa la determinación de la curva de disociación Hb:O2. El método presentado para establecer la curva de disociación Hb:O2 (CDO) simplifica los protocolos normalmente utilizados, ya que elimina el requerimiento del equipo específico para equilibrar la sangre con oxígeno en niveles fijos de presión parcial (PO2). Mediante el uso de ecuaciones matemáticas es posible establecer la cinética de saturación de la hemoglobina (SO2) a valores crecientes de PO2. De igual forma, mediante el método se determinan aspectos típicos de la unión Hb: O2 como la dependencia del pH (coeficiente de Bohr) y el tipo de asociación de la proteína con su ligando mediante el diagrama de Hill. En virtud de la simplificación realizada, el método es aplicable en prácticas de laboratorio en población humana y animal, así como en la investigación de diferentes condiciones experimentales.

ABSTRACT The affinity of hemoglobin (Hb) for oxygen (O2) is an important factor influencing the transport of this gas especially in hypoxia and in different diseases such as anemia or cystic fibrosis. By the affinity measurement, the determination of the Hb: O2 dissociation curve is used. The presented method to establish the Hb: O2 oxygen dissociation curve (CDO) simplifies the protocols normally used, since it eliminates the requirement of specific equipment to equilibrate blood with oxygen at fixed levels of oxygen pressure (PO2). By using mathematical equations, it is possible to establish the saturation change of hemoglobin (SO2) at increasing oxygen partial pressure. Similarly, the method determines typical aspects of the Hb: O2 binding as the pH dependence (Bohr coefficient) and the association type of protein with its ligand by the Hill diagram. By this simplification, the method is applicable in laboratory practices in human and animal population, as well as in the investigation of different experimental conditions.

Effect of Kangaroo mother care on physiological parameters in low birth weight neonates

Background: Low birth weight (LBW) babies require special care as they suffer from several handicaps, including maintenance of temperature, feeding, adequate weight gain and optimum neurobehavioral adaptation to the external environment. Kangaroo mother care (KMC) is an important modality that helps in the easy transition of the newborn infant to the outside world and overcomes the above problems. This study was planned to assess the effect of KMC on physiological parameters of low birth weight neonates, in a tertiary care hospital.Methods: This was a single-centered prospective observational quasi-experimental study conducted over a period of 18 months on 70 eligible LBW neonates. The arterial oxygen saturation, blood pressure (systolic, diastolic and mean), heart rate and respiratory rate of the neonates were noted. The readings at 1 hour and 2 hours after KMC were compared with that of the reading at 10 minutes prior to initiating KMC to assess the changes in the mentioned physiological parameters.Results: Analysis suggested statistically significant improvement in the arterial oxygen saturation and stabilization of the systolic, diastolic and mean blood pressure, heart rate and respiratory rate with institution of KMC. There was better improvement in the physiological parameters on increasing the duration of KMC from one hour to two hours and these changes were statistically significant.Conclusions: LBW neonates receiving KMC showed significant improvement in oxygen saturation and blood pressure, heart rate and respiratory rate.

Saturación de oxígeno/fracción inspirada de oxígeno como predictor de mortalidad en pacientes con exacerbación de EPOC atendidos en el Hospital Militar Central / Oxygen saturation / fraction of inspired oxygen as a predictor of mortality in patients with exacerbation of COPD treated at the Central Military Hospital

Resumen Introducción: la validez de la relación saturación arterial de oxígeno y fracción inspiratória de oxígeno (SaO2/FiO2), calculada por oximetría de pulso y por gases arteriales en pacientes con exacerbación de la enfermedad pulmonar obstructiva crónica (E-EPOC) a la altitud de Bogotá no son conocidos, los pacientes con EPOC pueden presentar alteraciones en el intercambio de gases que pueden empeorar con los episodios de broncoespasmo, obtener valores de la SaO2 por oximetría y FiO2 puede brindar información valiosa sobre el curso de la exacerbación. Objetivo: determinar la validez de la relación SaO2/FiO2 calculada por oximetría de pulso y por gases arteriales con relación a los desenlaces de ventilación mecánica (VM) y mortalidad a siete y 30 días. Métodos: se realizó un estudio de cohorte prospectivo con análisis de prueba diagnóstica calculando los puntajes DECAF, BAP-65, CURB-65, gases arteriales y oximetría de pulso al ingreso de pacientes con E-EPOC, se evaluó el desenlace de mortalidad a los siete y 30 días de ingreso y el requerimiento de VM durante su hospitalización, se calculó la relación SaO2/FiO2 utilizando la SaO2 obtenida en los gases arteriales y de manera independiente la relación SaO2/FiO2 con la SaO2 obtenida por oximetría de pulso, con los datos obtenidos se calculó los valores de sensibilidad (S), especificidad (E), valor predictivo positivo (VPP), valor predictivo negativo (VPN), razón de verosimilitud positiva (LR+), razón de verosimilitud negativa (LR-) y área bajo la curva de características operativas del receptor (ACOR). Resultados: se analizaron 462 E-EPOC, el requerimiento de VM fue de 14.3% y mortalidad a 30 días de 5.71%, la sensibilidad de la relación SaO2/FiO2 calculada por oximetría de pulso para desenlace de VM fue de 84.6% (IC95%:75-94.2), especificidad 42% (IC95%:37- 47), VPP: 19.6% (IC95%:14.8-24.4), VPN: 94.3% (IC95%:90.5-98), LR+: 1.46 (IC95%:1.28-1.67), LR: 0.37(IC95%:0.20-1.67), ACOR: 0.779% (IC95%:0.711-0.847) p<0.0001, la sensibilidad de relación SaO2/FiO2 por gases arteriales para VM fue de 83% (IC95%:73.2-92.9), especificidad 57% (IC95%:51.9-62.2), VPP: 24.8% (IC95%:18.8-30.7), VPN: 95.2% (IC95%:92.2-98.2), LR+: 1.94 (IC95%:1.65-2.27), LR-: 0.30 (IC95%:0.17-0.51), ACOR: 0.799% (IC95%:0.737-0.861) p<0.0001, la sensibilidad de la relación SaO2/FiO2 por oximetría para desenlace de mortalidad tiene una sensibilidad del 76.8% (IC95%:58.8-95), especificidad de 39.2% (IC95%:34.4-43.9), VPP: 7.1% (IC95%:3.9-10.3), VPN: 96.5% (IC95%:93.5-99.5), LR+: 1.26 (IC95%:1.01-1.58), LR-: 0.59 (IC95%:0.29-1.20), ACOR: 0.689% (IC95%:0.568-0.810) p<0.0001, la sensibilidad de la relación SaO2/FiO2 por gases arteriales para mortalidad fue de 80.8% (IC95%:63.7-97.8), especificidad 53.2% (IC95%:48.3-58), VPP: 9.6% (IC95%:5.5-13.8), VPN: 97.8% (IC95%:95.7-99.9), LR+: 1.73 (IC95%:1.39-2.14), LR-: 0.36 (IC95%:0.16-0.80), ACOR: 0.732% (IC95%:0.617-0.846) p<0.0001. Conclusión: los valores de SaO2/FiO2 calculados por oximetría y por gases arteriales pueden ser útiles para predecir desenlaces de VM y mortalidad en pacientes con exacerbación de la EPOC. (Acta Med Colomb 2017; 42: 215-223).

Abstract Introduction: the validity of the ratio arterial oxygen saturation and inspiratory oxygen fraction (SaO /FiO2), calculated by pulse oximetry and by arterial gases in patients with exacerbation of chronic obstructive pulmonary disease (E-COPD) at the altitude of Bogotá are not known. Patients with COPD can present alterations in gas exchange that can worsen with bronchospasm episodes. Obtaining values of SaO2 by oximetry and FiO2 can provide valuable information on the course of the exacerbation. Objective: to determine the validity of the SaO2/ iO2 ratio calculated by pulse oximetry and by arterial gases in relation to mechanical ventilation (VM) outcomes and mortality at seven and 30 days. Methods: a prospective cohort study with diagnostic test analysis was performed, calculating DECAF, BAP-65, CURB-65, arterial blood gas and pulse oximetry scores on admission of patients with E-COPD, and the outcome of mortality was evaluated at seven and 30 days of admission and the MV requirement during hospitalization; the SaO2/FiO2 ratio was calculated using the SaO2 obtained in the arterial gases and independently the SaO2/FiO2 ratio with the SaO2 obtained by pulse oximetry. With the data obtained, the values of sensitivity (S), specificity (E), positive predictive value (VPP), negative predictive value (NPV), positive likelihood ratio (LR +), negative likelihood ratio (LR-) and low area the operating characteristics curve of the receiver (ACOR) were calculated. Results: 462 E-COPD were analyzed; the MV requirement was 14.3% and 30-day mortality of 5.71%, the sensitivity of the SaO2/FiO2 ratio calculated by pulse oximetry for MV outcome was 84.6% (95% CI : 75-94.2), specificity 42% (95% CI: 37-47), PPV: 19.6% (95% CI: 14.8-24.4), NPV: 94.3% (95% CI: 90.5-98), LR +: 1.46 (95% CI : 1.28-1.67), LR: 0.37 (95% CI: 0.20-1.67), ACOR: 0.779% (95% CI: 0.711-0.847) p <0.0001, sensitivity of SaO2/FiO2 ratio for arterial blood gases for MV was 83% (95% CI: 73.2-92.9), specificity 57% (95% CI: 51.9-62.2), PPV: 24.8% (95% CI: 18.8-30.7), NPV: 95.2% (95% CI: 92.2-98.2), LR +: 1.94 (IC95%: 1.65-2.27), LR-: 0.30 (IC95%: 0.17-0.51), ACOR: 0.799% (IC95%: 0.737-0.861) p <0.0001, the sensitivity of the SaO2/FiO2 ratio by oximetry for outcome of mortality has a sensitivity of 76.8% (95% CI: 58.895), specificity of 39.2% (95% CI: 34.4-43.9), PPV: 7.1% (95% CI: 3.9-10.3), NPV: 96.5% (95% CI : 93.5-99.5), LR +: 1.26 (IC95%: 1.01-1.58), LR-: 0.59 (CI 95%: 0.29-1.20), ACOR: 0.689% (IC95%: 0.568-0.810) p <0.0001, the sensitivity of the SaO2/FiO2 ratio for arterial blood gases was 80.8% (95% CI: 63.7-97.8), specificity 53.2% (95% CI: 48.3-58), PPV: 9.6% (95% CI: 5.5-13.8), NPV: 97.8% (95% CI: 95.7-99.9), LR +: 1.73 (95% CI: 1.39-2.14), LR-: 0.36 (IC95%: 0.16-0.80), ACOR: 0.732% (IC95%: 0.617-0.846) p <0.0001. Conclusion: SaO2/FiO2 values calculated by oximetry and arterial blood gases can be useful to predict MV outcomes and mortality in patients with exacerbation of COPD. (Acta Med Colomb 2017; 42: 215-223).

Metodología geométrica para la evaluación de la saturación arterial de oxígeno en pacientes de la Unidad de Cuidados Intensivos / Geometric methodology for the saturation evaluation arterial oxygen in patients of the Care Unit Intensive

Introducción: En cardiología, la aplicación de teorías, como la de los sistemas dinámicos y la geometría fractal, han generado nuevos diagnósticos matemáticos que diferencian, de manera geométrica y cuantitativa, el comportamiento normal del enfermo a partir de la ocupación del atractor caótico cardíaco. El objetivo de este estudio fue desarrollar, en el contexto de la teoría de los sistemas dinámicos, una metodología de evaluación de la saturación arterial de oxígeno para pacientes en la Unidad de Cuidados Intensivos. Materiales y Métodos: Se seleccionaron 10 pacientes con diferentes enfermedades, provenientes de la Unidad de Cuidados Intensivos, a los cuales se les registró la saturación arterial de oxígeno durante su estancia en la Unidad, y se construyeron atractores caóticos en el mapa de retardo. Posteriormente, se establecieron cuantificaciones de los valores mínimos y máximos del atractor. Resultados: Los valores máximos y mínimos de los atractores de la saturación de oxígeno variaron entre el 100% y el 70%, para los pacientes que fallecieron, mientras que para aquellos que vivieron, se mantuvo entre el 99% y el 85%. Conclusiones: Se observó un comportamiento caótico asociado a la saturación arterial de oxígeno, cuantificable a partir de los valores máximos y mínimos hallados de la totalidad del atractor, estableciendo una nueva medida matemática y física del paciente crítico en la Unidad de Cuidados Intensivo (AU)

Introduction: In cardiology, the application of theories, such as dynamical systems and fractal geometry, has generated new mathematical diagnoses that differentiate geometrically and quantitatively the normal from the diseased behavior through the occupation of the cardiac chaotic attractor. The objective of this study was to develop, in the context of the dynamical systems theory, a methodology for the evaluation of arterial oxygen saturation in patients of the Intensive Care Unit. Materials and Methods: Ten patients with different pathologies from the Intensive Care Unit were selected. The arterial oxygen saturation was recorded during their stay in the Intensive Care Unit and chaotic attractors were built in the delay map. Subsequently, quantifications of the minimum and maximum values of the attractor were established. Results: The maximum and minimum values of the oxygen saturation attractors varied between 100% and 70% for patients who died, whereas for those who lived, saturation values between 99% and 85% were maintained. Conclusions: A chaotic behavior associated with arterial oxygen saturation, quantifiable through the maximum and minimum values found in the entire attractor, was observed, establishing a new mathematical and physical measurement of the critical patient in the Intensive Care Unit.(AU)

Early warning of high altitude pulmonary edema / 军事医学

Objective By analyzing the clinical symptoms, heart rate ( HR) , arterial oxygen saturation ( SaO2 ) and the number of white blood cells (WBC), we aimed to explore the implication of the above-mentioned indexes for early warning of high altitude pulmonary edema ( HAPE) .Methods Based on the Lake Louise Self-assessmeat Scoring System ( LLSS) and the scoring of respiratory symptoms, 628 subjects were divided into three groups: group A ( the healthy;score3 and excluding HAPE),and group C (HAPE).Moreover, we analyzed the incidence of some clinical symptoms, HR and SaO2 , as well as the WBC number of some subjects in the three groups.Results The incidence of respiratory symptoms and WBC number were significantly increased in group C compared with group B(P30%) have high risk of HAPE.It is of special importance to detect HAPE earlier at high altitude.

Prophylactic Effect of Erythropoietin Injection to Prevent Acute Mountain Sickness: An Open-Label Randomized Controlled Trial

This study was performed to evaluate whether increasing hemoglobin before ascent by prophylactic erythropoietin injections prevents acute mountain sickness (AMS). This open-label, randomized, controlled trial involved 39 healthy volunteers with hemoglobin or =3 were present. Immediate descent criteria followed US Army recommendations. Two groups differ in hemoglobin levels on day 29 (15.4+/-1.1 vs 14.2+/-1.0 g/dL, P=0.001). At ABC, erythropoietin group had a significantly lower mean LLS, AMS incidence, and number of subjects who met immediate descent criteria. Multiple logistic regression analysis showed that SaO2<87% and control group, but not hemoglobin<15.0 g/dL, independently predicted satisfaction of immediate descent criteria. Erythropoietin-related adverse effects were not observed. In conclusion, erythropoietin may be an effective prophylaxis for AMS.(Clinical Trial Registry Number; NCT 01665781).

Effect of pre-acclimatization training under hypoxic environment for one week on work capacity and physiological responses under hypoxic environment / 体力科学

We examined the effect of pre-acclimatization training under hypoxia for competition or training at high altitude on work capacity and physiological responses in hypoxia. Eight healthy male university students performed pre-acclimatization training under normobaric hypoxia (equivalent to about 2500 m; 15.4% inspired oxygen) for a week. Each student was exposed for a total of 90 minutes. During the exposure, each student rested for 60 minutes and pedaled at a workload of lactate threshold (LT) under normobaric hypoxia (equivalent to about 2500 m) for 30 minutes. In the result, workload of LT under normobaric hypoxia significantly increased after pre-acclimatization training (+15%). In physiological responses, arterial oxygen saturation at rest and exercise and peak ventilatory volume significantly increased after pre-acclimatization training. Arterial oxygen saturation at rest during pre-acclimatization training significantly increased. In addition, the ratio of low- and high-frequency power in heart rate variability significantly decreased after pre-acclimatization training. These results suggest that pre-acclimatization training is able to bring in acclimatization to high altitude on cardiopulmonary function and prevent decline of work capacity in high altitude. The ratio of low- and high-frequency power in heart rate variability as well as arterial oxygen saturation may reflect degree of acclimatization to high altitude.

Usefulness of Percutaneous Oxygen Saturation Monitoring as a Predictor of Deterioration of Lung Function in Korean Children with Asthma / 소아알레르기및호흡기학회지

PURPOSE:Our study was designed to verify the correlation between the level of percutaneous arterial oxygen saturation (SpO2) and forced expiratory volume in 1 second (FEV1) and to classify the severity according to SpO2 level when asthma exacerbation is developed. METHODS:We performed the methacholine bronchial provocation tests with monitoring SpO2 on 350 children who visited the pediatric allergy clinic with chronic cough or recurrent wheezing from August 2006 to August 2008. RESULTS:There was a significant correlation between FEV1%fall and SpO2 (r=-0.814, P< 0.01). The mean value of SpO2 was 95.80%+/-1.2% when decrement of FEV1 was 20%. It was 92.3%+/-0.81% when FEV1 decreased by 40%. CONCLUSION:Monitoring SpO2 is a convenient and reliable objective method to determine an appropriate therapeutic option when the pulmonary function test or arteial blood gas analysis is not available in children with asthma. We suggest less than 96% of SpO2 for the moderate attack, less than 92% for the severe attack, as the criteria for the severity of asthma exacerbations in Korea, which is higher than those suggested by GINA guideline or Japanese guidelines.

The effect of spinal anesthesia on pulse oximetry / 대한마취과학회지

BACKGROUND: Pulse oximetry provides valuable data on the arterial oxygen saturation. Significant impairment in the arterial oxygen saturation can occur under vasoconstriction, hypothermia, and hypotension. This study compared the percutaneous oxygen saturation (SpO2) at the hand and the foot with the arterial oxygen saturation (SaO2) during spinal anesthesia. METHODS: Twenty eight, ASA physical status 1 or 2, patients received a spinal block with 0.5% hyperbaric bupivacaine. Two pulse oximeter probes were applied to the index finger and second toe of the patients, and the SpO2 values were recorded before, 10, 20, and 30 minutes after the intrathecal injection. The SaO2 was measured before and 30 minutes after the intrathecal injection. RESULTS: During spinal anesthesia, there were similar changes in the SpO2 value from the hand. However, there was a progressive decrease in SpO2 of the foot of 97.6 +/- 2.8%, 97.3 +/- 2.8%, and 97.2 +/- 3.3% at 10, 20, and 30 minutes, respectively (P < 0.05 compared with the baseline). There were significant differences between the hand and foot SpO2 in 20 and 30 minutes (0.79 +/- 1.55%, 0.93 +/- 1.86%) after the intrathecal injection. The SaO2 value was similar before and 30 minutes after the intrathecal injection. Before spinal anesthesia, there were significant differences between the SaO2 (96.4 +/- 2.6%) and SpO2 values of the hand (98.1 +/- 2.6%) and the foot (98.3 +/- 2.6%). CONCLUSIONS: During spinal anesthesia, it is appropriate to measure the SpO2 from the hand because it dose not change significantly.

A Case of Using Open-Close Valve during One Lung Ventilation: A case report / 대한마취과학회지

One lung ventilation for thoracic surgery may reduce arterial oxygen saturation by ventilation-perfusion mismatching and by increasing intrapulmonary shunting. We experienced a 52 year old male patient with a lung abscess, who showed arterial desaturation after one-lung ventilation. The authors tried to increase arterial oxygen saturation by applying positive end-expiratory pressure (PEEP) and continuous positive airway pressure (CPAP) to dependent and nondependent lung, respectively. However, arterial oxygen saturation did not increase. So, we applied partial differential lung ventilation using an open-close valve designed by the authors, and arterial oxygen saturation increased rapidly. The advantages of the open-close valve are its straightforward use and ease of manipulation. We report a case involving the use of this open-close valve in a desaturated patient during one lung ventilation.

Difference of Hypoxia Tolerance with Reference to Sex

BACKGROUND: Time of useful consciousness is related with various factors including smoking, age, sex, drug, and temperature. It is still unclear whether acute hypoxia tolerance is different between male and female. METHOD: We included 32 healthy students (male, n=16; female, n=16) volunteered to participate in this study. The blood hemoglobin concentration was measured at a day before flight. With high altitude rapid decompression flight training chamber, flight to simulated altitude of 25,000 ft was performed after nitrogen extraction breath. At 25,000 ft, heart rate and arterial O2 saturation (SaO2) were measured by using pulse oximeter after taking off oxygen mask. We compared the duration from mask-off to the time at 60% SaO2 between male and female and correlated the time at 60% SaO2 with hemoglobin concentration. RESULTS: The duration from mask-off to SaO2 reaching 60% were significantly longer in the male group. There was a linear relationship between hemoglobin concentration and time at 60% SaO2. CONCLUSION: Acute hypoxia tolerance differs from the two sexes and the difference of hemoglobin concentration is one of possible causative factors of this difference.

Surgical Treatment of Ventricular Septal Defect with Severe Pulmonary Hypertension in 37 Patients / 中国医师杂志

Objective To summarize the operative experience of ventricular septal defect(VSD) with severe pulmonary hypertension(PH).Methods 37 patients with VSD complicated with severe PH,who underwent surgical repair were treated combinatively in perioperative period including resting,oxygen inhalation,and administration of captoprill and prostaglandin E 1(PGE 1).All of the patients were operated by cardiopulmonary bypass with moderate hypothermia.Arterial oxygen saturation(SaO 2),pulmonary arterial pressure and cardiac function were observed before and after operation,and progression of cardiac function and mortality were followed-up after discharged.Results 2 patients died of low cardiac output syndrome(LCOS) and one patient died of respiratory failure,and the operative mortality was 8 1%.one patient was diad after 8 months and the cardiac function of 33 patients markedly improved.Conclusions Reasonable treatment in perioperative period and holding the indications for the operation strictly are the keys to decrease the mortality of the operation,and SaO 2 could be a simple measurement to identify the indication of operation and the prognosis of the patient with VSD complicated with severe PH.

The Effectiveness of Propofol on Pediatric Cardiac Catheterization and Electrophysiologic Study

PURPOSE: Our purpose was to evaluate the effectiveness of propofol on pediatric cardiac catheterization or radiofrequency catheter ablation. METHODS: We measured the serial changes of arterial oxygen saturation, heart rate, systolic and diastolic blood pressure at 4 stages, a baseline(during normal sleep), stage 1(just after loading of propofol 2 mg/kg over 10 minutes), stage 2(10-15 minutes after propofol continuous intravenous infusion at 50 microg/kg/min), and stage 3(25-30 minutes after continuous infusion). RESULTS: Serial changes of arterial oxygen saturation were 96.4+/-7.7, 96.7+/-6.5, 97.0+/-5.2, and 96.5+/-6.1% respectively, with a significant but mild decrease between stage 2 and stage 3(P<0.05), and no significant decrease as compared with the baseline value. There were no significant changes of heart rate(102+/-22, 101+/-21, 100+/-19, 99+/-17 beats/min.), systolic blood pressure(103+/-12, 101+/-14, 103+/-17, 104+/-15 mmHg) and diastolic blood pressure(55+/-10, 52+/-9, 54+/-13, 52+/-9 mmHg). Mean time to complete recovery of consciousness was 19+/-20(+/-2SD) minutes. Oxygen supplementation was required in five cases, and oxygen saturation was sastained stable after administration of the oxygen at the rate of 2-4 L/min. CONCLUSION: During invasive pediatric cardiac procedure, intravenous propofol sedation had no significant impacts on heart rate and blood pressure but some impacts on arterial oxygen saturation which was easily corrected by oxygen administration. Propofol might be considered as a relatively safe and effective sedative drug in pediatric cardiac invasive procedures.

Validity on Postoperative Routine Supplemental Oxygen Using Pules Oximetry-Determining factor on the Postoperative Arterial Hypoxemia / 대한마취과학회지

Routine use of supplemental oxygen(O2) in the recovery room traditionslly has been used to minimize the incidence of hypoxemia. However with the advent of continuous noninvasive monitoring by pulse oximetry is routine administration of O2 necessary? We hypothesized that administration O2 as needed based on pulse oximetry dats, would effect without compromieing patient care. And factors that might influence the incidence of post-operative hypoxemia were analyzed. On hundred thirty eight adult (> or = 18yrs) patients were enrolled in the study. During recovery room care, when O2 saturation(SpO2) was continuously more than 94%, no supplemental O2 was given. When SpO2 was less than 94%, supplemental O2 was given by face mask(O2 51/min). SpO2 and Aldrete score(AS) were measured at preoperatively, at the end of anesthesia, on arrival in the recovery room, at 10 min, 20 min and 30 min after arrival in the RR and at discharge. The results are as follows: 1) Supplemental O2 was unneeessary in the 55.8% of patient for the duration of the recovery room stay. 2) A significant multiple correlation was found between low SaO2 level, while breathing room air on arrivsl in the recovery room and preoperative SpO2, weight and Aldrete score on arrival in the recovery room. With the above results the authors concluded that in as much as pulse oximetry monitoring is now standard in the recovery room, administration O2 as need based on the pulse oximetry data would effect without compromising patient care, and that preoperative oxygen saturation and weight are the main factors influencing early postopertative hypoxemia in this study.

Prevention of Arterial Oxygen Desaturation during Endotracheal Suction / 대한마취과학회지

The purpose of this study was to determine the frequency and severity of arterial oxygen desaturation during and after endotracheal suctioning in a group of ventilator-dependent patients and to evaluate the efficacy of several maneuvers designed to minimize desaturation. All patients were ventilated with volume-typed ventilator and a synchronized intermittent mandatory ventilation(SIMV) mode was utilized. In a given patint, each study consisted of four seperate passes of the suction catheter. The oxygen status of the patient was monitored with a digital pulse oxymeter. The mean baseline SaO2 for the group with each suctioning technique was very similar and did not differ significantly. When patints were suctioned off the ventilator without extra breaths, a significant drop occurred in the mean SaO2 And when the patients were suctioned with prebreaths and postbreaths off the ventilator or were maintained on the ventilator and suctioned through the swivel adaptor, there was a significant desaturation with all three methods. However, the mean desaturation of 0.8 percent with the swivel adaptor was significantly less(p<0.05) than the mean desaturation with any of the other three methods.

Comparative Study of Time - dependent Changes of Arterial Oxygen Saturation between upper Extremity and Lower Extremity in Spinal Anesthetic Patients / 대한마취과학회지

To study the effect of one part of hemodynamic changes following spinal aneethesia on the time-dependent change of aterial oxygen saturation (SaO2) from the upper extremities and lower extremities, we analyzed the ASA class I, 30 patients (Group I, Tetracaine only (n =15), 40+/-6 years, 58+/-7kg, 162+/-6cm, Group II, Tetracaine+/-Epinephrine (n=15), 41+/-6 years, 59+/-6kg, 161+/-7cm) scheduled for urologic surgery under lower spinal anesthesia. The results were as follows: 1) There was no significant difference of preanesthetic SaO2 between upper and lower extremities in two groups (p>0.05). 2) There was no significant diference of time-dependent changes of postanesthetic SaO, in the upper extremities as compared with preanesthetic value (p=0.05). 3) There was significant ifference of time-dependent changes of postanesthetic SaO2, at 5 min, 10 min and 15 min in the lower extremities of Group I, on the other hand, at 10 min and 15 min in Group II as compared with control value (p<0.05). 4) There was significant difference of postanesthetic SaO at 10 min and 15 min in the lower extremities between two groups (p<0.05). 5) It took more longer to reach the maximum level of SaO2, after inal anesthesia in Group II as compared with Group I (p<0.05).

A Clinical Study on Arterial Oxygen Saturation in the Early Period of Anesthetic Recovery from General Endotracheal Anesthesia / 대한마취과학회지

To investigate the incidence of hypoxemia which was defined as arterial blood oxygen saturation (SaO2) of 90% or less following general endotracheal anesthesia, 112 adult patients were randomly allocated to one of 8 groups aceording to oxygen administration or not. SaO2 was continually measured during postanesthetic period using a pulse oximeter (Nellcor, N-100 C, USA). The incidence of hypoxemia was lower in oxygen administration groups (5%) than in no administration groups (14%) in the recovery room. The mean discharge time of oxygen administration groups in the recovery room (37.9 min) was significantly shorter than that of no administration groups (45.6 min) (P=0.003). There were two cases of hypoxemia during transfer of patients from the operating room to the recovery room. The incidence of hypoxemia in oxygen administration groups (9%) was lower than no oxygen administration groups (71%) during 5 minutes after endotracheal extubation. It was coneluded that the incidence of hypoxemia can be reduced by administrating oxygen during postanesthetic period. Therefore, it is recommended that oxygen should be administered to all postoperative patients for prevention of hypoxemia following general endotracheal anesthesia.

Changes of Arterial Oxygen Saturation after Pediatric Anesthesia / 대한마취과학회지

In postanesthetic period, infants and children have a risk of hypoxemia due to decreased functional residual capacity(FRC) and increased alveolar-arterial O2 tension gradient(A-a DO2). We measured arterial oxygen saturation(SaO2) with a pulse oximeter in 60 ASA class 1 infants and children. Group 1 was breathing with supplemental oxygen(4L/min) by mask and Group 2 was breathing with room air in recovery room after general anesthesia. SaO2 was measured on arrival in the recovery room, 2,4,6, 8,10,15, and 20 minute after arrival The results were as follows: 1) Postanesthetic SaO2 measured on arrival in the recovery room had decreased significantly(p<0.05) to preanesthetic SaO2 2) SaO2 measured in room air had decreased significantly compared with SaO measured in supplemental oxygen. As a result of the study, it is thought to be safe that supplemental oxygen is administered to patient on transfer and in recovery room.