• Journal of Chest Surgery
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• 제13권2호
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• pp.85-91
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• 1980

Extracorporeal circulation by hemodilution technique has been currently used with its clinical safety and good peripheral tissue perfusion in open heart surgery. There is no doubt that $O_{2}$ carrying capacity of the blood is disturbed by decreased hemoglobin level resulting from hemodilution of the circulating blood. From the view point of the blood gas exchange, these experimental studies were undertaken to determined the sate limit of hemodilution in the condition of cardiopulmonary bypass with a constant perfusion flow rate. Twelve adult mongrel dogs weighing 10 to 13 Kg. were anesthetized with pentobarbital and then respiration was controlled with Harvard volume respirator using room air. The cardiopulmonary by pass was performed by use of Sarns heart lung machine (console 5000, 5 head and 2 roller pumps) and Travenol pediatric bubble oxygenator. The perfusion rate during bypass was maintained at a constant rate of 80 ml/min/Kg of body weight. The ratio of oxygen gas flow to blood flow was kept in 3 to 1 constantly. International hemodilution was attained by serial blood withdrawals and immediate infusion of equal volumes of diluants composed of Ringer's lactate, 5% dextrose in water and 25% mannitol solution, proportionally 60%, 30%, and 10%. Arterial and venous blood samples were obtained between 15 and 20 minutes following each hemodilution. Hematocrits and hemoglobin values, $PO_{2}$, $PCO_{2}$ and pH were measured. Oxygen and carbon dioxide contents oxygen consumption and carbon dioxide elimination were calculated groups according to different hematocrit values and the correlations were evaluated. Result were as follows. 1. the arterial $O_{2}$ tension and $O_{2}$ saturation were maintained at the physiological level irrespective of the hematocrit value. 2. The venous $O_{2}$ tension and $O_{2}$ saturation showed a tendency to decline with the decrease in hematocrit value and positive correlation between them (r = +0.49, r = +0.76), The mean values of venous $O_{2}$ tension and $O_{2}$ saturation, however, were not decreased when the hematocrit levels were lower than 20%. 3. The arterial $O_{2}$ content declined lineally in proportion to the fall of hematocrit level with a positive correlation between them (r = +0.95). 4. The venous $O_{2}$ contents were decreased gradually as the hematocrit value decreased with positive correlation between them ( r =+0.89). The trend of diminution of venous $O_{2}$ content, however, was became low according to progressive decrease of hematocrit level. 5. Systemic oxygen consumption was in higher range than $O_{2}$ requirement of basal metabolism when the hematocrit value was above 20%, but abruptly decreased when the hematocrit value became to below 20%. 6. The arterial $CO_{2}$ tension and $CO_{2}$ content showed trend of increasing with progressive decrease of hematocrit value but exhibited a rather broad range and there was no relationship between those value and the hematocrit value. 7. The venous $CO_{2}$ tension and $CO_{2}$ content have also no correlation with change of Ht. value but related directly to those value of arterial blood with positive correlation between them (r = +0.78, r = +0.95_. 8. A-V difference of $CO_{2}$ content and $CO_{2}$ elimination wasnot significantly influenced by Ht. value. From the results, we obtained that feasible limit in inteneional hemodilution is above the hematocrit value of 20% under the given experimental condition.

• Journal of Korean Biological Nursing Science
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• 제14권4호
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• pp.275-281
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• 2012

Purpose: This study was performed to evaluate the effect of low-dose lidocaine on fentanyl-induced cough and hemodynamic changes under general anesthesia. This research was a randomized trial design and performed using a double-blind method. Methods: Data collection was performed from October 22, 2008, to May 4, 2009. One hundred and thirty two patients were randomly assigned to control group (Con G) and experimental group (Exp G) using a table of random numbers. Exp G (n=66) were administered 0.5 mg/kg lidocaine and Con G (n=66)) were administered saline. The occurrence of cough and vital sign were recorded within one minute after fentanyl bolus by an anesthesiologist. Collected data were analyzed using Repeated measures ANOVA using SPSS for Windows (Version 17.0). Results: The incidence of cough in Exp G was 13.6%, while Con G was 53%. The incidence cough in Exp G was significantly lower compared to Con G (p<.001). Lidocaine seemed not to suppress mean arterial pressure (p=.145), heart rate (p=.508), and oxygen saturation (p=.161). Conclusion: Intravenous administration of 0.5 mg/kg lidocaine seems to suppress fentanyl-induced cough without affecting mean blood pressure, heart rate and oxygen saturation. Therefore, we recommend intravenous 0.5 mg/kg lidocaine administration to suppress fentanyl-induced cough under general anesthesia.

• Journal of Yeungnam Medical Science
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• 제15권1호
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• pp.97-113
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• 1998

교감신경계는 광범위한 각종 기능의 항상성 조절에 결정적인 역할을 하고 있으며, 저산소증, 출혈, 통증 등에 따른 스트레스 반응에 의해 자극되어 심박출량의 증가 및 조직으로 산소공급 향상을 위한 혈류 조절 반응이 나타나게 되나 주어진 환경에 따라 반응 정도는 다양하게 보고되고 있다. 고농도의 $N_2O$로 인해 발생된 저산소혈증 상태에서 혈역학적 변화가 저산소혈증을 발견하는 지표로서 유용한 지를 관찰하기 위해 본 실험에서는 마취후 기계적 환기를 시행한 한국산 잡견에서 고농도의 $N_2O$를 이용하여 흡입산소농도를 점진적으로 감소시킬 때 발생된 저산소혈증이 혈중 catecholarnine의 분비와 혈액 가스 및 혈역학적 변화를 비교 관찰하였다. Halothane으로 흡입 마취하여 기계적 환기를 시행한 뒤 10 마리의 한국산 잡견에서 21%, 15%, 10%, 5%의 산소를 5분씩 공급하여 혈역학상의 변화와 조직의 산소이용 상태 및 혈중 catecholamine치를 관찰하여 다음과 같은 결과를 얻었다. 조절호흡의 결과, 실험견은 등탄산성 저산소혈증이 초래되었으며 흡입산소농도의 감소 정도에 따라 동맥혈 및 혼합정맥혈의 산소분압 및 포화도가 감소되었고, 산소섭취율이 증가함에 따라 동정맥혈 산소함량의 차이는 증가하였으며 동시에 심박출량이 증가하는 대상성 반응을 보였다. 중심 정맥압은 10%와 5%의 흡입산소농도에서 측정치가 유의하게 증가되었고, 평균 폐동맥압은 10%와 5%의 흡입산소농도에서 각각 55% 및 82% 증가되었으며 폐혈관저항도 각각 76%, 95%로 유의하게 증가되었으나 전신혈관저항의 변화는 유의성이 없었다. 실험견에서 혈중 norepinephrine, epinephrine 및 dopamine의 대조치는 각각 $141.4{\pm}94.4$ pg/ml, $172.6{\pm}130.1$ pg/ml, $151.1{\pm}282$ pg/ml이었다. 15% 산소 흡입 시 norepinephrine, epinephrine 및 dopamine치는 모두 유의한 증가를 나타내기 시작하였고 dopamine은 10% 흡입산소농도에서 가장 많이 증가하였으나 5% 흡입산소농도에서는 오히려 감소되었고 60%의 흡입산소로 재산소화하는 동안 대조치 수준으로 회복되었다. 이에 비해 norepinephrine은 15%의 흡입 산소농도에서 74% 증가한 후 저산소혈증이 심화될수록 더욱 증가하는 양상이 계속되었다. Epinephrine은 대조치에 비해 15% 산소 흡입시 29% 증가하였으나 10% 및 5% 흡입산소농도에서 각각 382%, 350% 증가되었다. 60%의 흡입산소로 재산소화하였을 때는 norepinephrine과 epinephrine치는 감소되었으나 대조치보다는 여전히 증가되어 있었다. 이상의 결과로 볼때 마취후 고농도의 $N_2O$에 의한 저산소 가스 흡입은 혈중 catecholamine의 농도를 증가시키나 심혈관계 및 교감 신경계의 반응을 매우 둔화시키는 것으로 생각된다. 따라서 임상 마취에서 환자에게 고농도의 $N_2O$를 흡입시켜 저산소혈증이 초래되는 경우 혈압 및 맥박수의 변화는 저산소혈증을 발견하는 지표로 유용하지 않은 것으로 사료된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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• pp.117-120
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• 2000

Pulse oximetry is a well established non-invasive optical technique for monitoring the SpO$_2$ during anaesthesia, recovery and intensive care. Pulse oximeters determine the oxygen saturation level of blood by measuring the light absorption of arterial blood. The sensors consists of red and infrared light sources and photodetectors. In the measurement of the hemoglobin oxygen saturation, conventional method has required the technique of filtering of remove the noise, and of complex signal processing algorithm. So much time have required to signal processing. In this research, we separate AC signal and DC signal in the stage of signal detection. We filter the noise from each signal and convert A/D. We obtain the SpO$_2$ using the DSP algorithm.

• 한국광학회지
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• 제11권6호
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• pp.452-456
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• 2000

동맥혈의 맥동성분에 의한 파장별 광흡수도를 측정하여 비침습적으로 산소포화도 값을 알수 있는 펄스옥시미터 장치와 신호처리방법을 개발하고 예측 알고리즘을 적용하였다. 본 장치는 광원 및 검출기로 구성된 프로브와 광신호 처리부, LED 구동회로 PC 인터페이스부로 구성되었고 데이터의 수집을 위한 구동소프트웨어 및 데이터 처리 소프트웨어를 개발하였다. 개발된 산소포화도 측정장치의 성능을 평가하는데에는 Bio-Tek 사의 펄스 옥시미터 시뮬레이터를 사용하여 다양한 알고리즘 및 데이터처리 방법들을 비교분석한 결과 맥동파형의 $In(I_p/I_v) 값을 I_{avr}$값으로 보정하는 계산 알고리즘의 방법과 진폭비보다 면적비를 이용한 계산방법이 산소포화도와의 상관관계가 우수한 것으로 나타났다. 정확한 신호 획득을 위해 개발된 맥동의 기저선 보상처리 프로그램을 inv-vivo 테스트의 데이터 처리방법에 적용하여 결과가 향상되는 것을 확인하였고 광원으로 660nm(Red)와 805nm(IR)파장을 이용한 경우보다 660nm(Red)와 940nm(IR) 파장을 이용했을 때 산소포화도와의 상관관계 및 정밀도에서 더 우수한 결과를 얻을 수 있었다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제20권2호
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• pp.73-81
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• 2020

Background: The 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 Methods: Each 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). Results: In total, 2899 SpO₂ data points obtained from 20 volunteers were used to determine the pharmacodynamic characteristics. The pharmacodynamic parameters were as follows: k_out = 0.942 1/min, Imax = 0.802, IC₅₀ = 85.3%, γ = 27.3. Conclusion: The changes in SpO₂ due to decreases in FiO₂ well explained by the turnover model with inhibitory function as a sigmoidal model.

• Journal of Dental Anesthesia and Pain Medicine
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• 제21권4호
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• pp.357-361
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• 2021

Methemoglobinemia is a blood disorder in which an abnormal amount of methemoglobin is produced, and prilocaine is one of the drugs that can cause this disorder. The maximum recommended dose of prilocaine is 8 mg/kg. We report a case of methemoglobinemia caused by the administration of 4.2 mg/kg of prilocaine without other methemoglobinemia-inducing drugs during general anesthesia. A 17-year-old girl with hyperthyroidism and anemia was scheduled to undergo maxillary sinus floor elevation and tooth extraction. The patient's peripheral oxygen saturation (SpO₂) decreased from 100% at arrival to 95% after receiving prilocaine with felypressin following induction of general anesthesia. However, the fraction of inspired oxygen was 0.6. Blood gas analysis showed that the methemoglobin level was 3.8% (normal level, 1%-2%), fractional oxygen saturation was 93.9%, partial pressure of oxygen was 327 mmHg, and arterial oxygen saturation was 97.6%. After administration of 1 mg/kg of methylene blue, her SpO₂ improved gradually to 99%, and the methemoglobin value decreased to 1.2%. When using prilocaine as a local anesthetic, it is important to be aware that methemoglobinemia may occur even at doses much lower than the maximum recommended dose.

• Tuberculosis and Respiratory Diseases
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• 제38권3호
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• pp.255-261
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• 1991

Frequently patients with chronic obstructive pulmonary disease have lowered arterial oxygen saturation in daytime. During sleep, they are apt to experience additional hypoxemia. These episode of nocturnal hypoxemia are usually associated with periods of relative hypoventilation. Noctunal hypoxemia may be associated with cardiac arrhythmia and with acute increase in pulmonary arterial pressure and may be implicated in the development of chronic pulmonary hypertension and cor pulmonale. We selected 14 patients with chronic obstructive pulmonary disease, 9 with emphysema dominant type and 5 with chronic bronchitis dominant type, to examine the frequency and severity of nocturnal hypoxemia and the effect of oxygen in prevention of nocturnal hypoxemia. The results were as follows; 1) On PFT, FVC, $FEV_1$, and $FEV_1$/FVC showed no significant difference between the emphysema dominant type (pink puffers, PP) and the chronic bronchitis dominant type (blue bloaters, BB). But DLCO/VA for the PP group was $45.7{\pm}15.1%$ which was significantly different from BB group, $82.4{\pm}5.6%$. 2) The daytime arterial oxygen saturation ($SaO_2$) and the lowest $SaO_2$, during sleep for the BB group were significantly lower than for the PP group. 3) The hypoxemic episodes during sleep were more frequent in BB group and the duration of hypoxemic episode was longer in BB group. 4) In both group studied, although there was a tendency for a lower L-$SaO_2$ (the lowest $SaO_2$, during sleep), an increase in hypoxemic episodes and duration as the daytime $SaO_2$, fell lower, the only parameter which showed significant correlation was daytime $SaO_2$, and the frequency of hypoxemic episodes in the PP group (r=-0.68, P<0.05). 5) In PP group, with oxygen supplementation, L-$SaO_2$, during sleep showed significant increase, and there was a tendency for the frequency of hypoxemic episodes and duration to fall but it was not significant. 6) In BB group, oxygen supplementation significantly increased the L-$SaO_2$ during sleep and also significantly decreased the frequency and duration of hypoxemic episode. From these results, we can see that oxygen supplementation during sleep can prevent the decrease in $SaO_2$ to some extent and that this effect of oxygen can be seen more prominently in the BB group.

• Tuberculosis and Respiratory Diseases
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• 제41권4호
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• pp.379-388
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• 1994

연구배경 : 수면 무호흡증후군은 수면시 반복적인 무호흡이 발생하여 일련의 심폐계통의 변화가 초래되는 질환으로 이중 동맥혈 산소포화도(arterial oxygen saturation, 이하 $SaO_2$)의 감소와 심부정맥의 발생이 임상적으로 중요한 소견이다. 무호흡시 $SaO_2$의 감소양상은 환자마다 다양하며 이는 호흡정지 기간, 호흡정지시의 산소공급원인 폐용량 및 개체의 산소소모율에 따라 결정될 것으로 예상된다. 방법 : 호흡정지와 재개시에 수반되는 $SaO_2$ 및 심박수(heart rate, 이하 HR)의 변동양상을 관찰하고, 그 변동에 관련되는 생리학적 인자들을 알아보고자 정상 남자 8명 및 정상 여자 9명 등 총 17명을 대상을 폐용량 측정, 동맥혈 가스분석을 시행하고 Harris-Benedict 식에 의거한 기초대사율을 산출한 뒤 총폐용량(total lung capacity, 이하 TLC), 기능적 잔기량(functional residual capacity, 이하 FRC) 및 잔기량(residual volume, 이하 RV) 상태에서 호흡정지를 시킨 후, $SaO_2$의 변동과 심전도를 측정기록하였다. 결과 : 호흡정지시 $SaO_2$가 기저치로부터 2% 감소하는데 걸린 시간(T2%)은 TLC, FRC 및 RV 에서 각각 $70.1{\pm}14.2$초 $44.0{\pm}11.6$초 및 $33.2{\pm}11.1$초로 TLC보다는 FRC 에서(p<0.05), FRC보다는 RV에서(p<0.05) 유의하게 단축되었다. T2%까지 호흡정지한 뒤 호흡재개시 $SaO_2$의 추가 감소는 RV에서 $4.3{\pm}2.1%$로서, TLC의 $1.4{\pm}1.0%$나 FRC의 $1.9{\pm}1.4%$ 보다 감소량이 컸고(각각 p<0.05), 최저 $SaO_2$치에서 기저치로의 회복에 걸린 시간은 TLC, FRC 및 RV에서 유의한 차이가 없었다. T2%는 각각의 폐용량 혹은 기초대사율과 유의한 상관관계는 없었으나, TLC/BMR(r=0.693, p<0.001) 및 FRC/BMR(r=0.615, p<0.025)과는 각각 유의한 상관관계를 보였고, RV/BMR(r=0.027, p>0.05)과는 유의한 상관관계가 없었다. 호흡정지와 재개의 전 과정에서 생긴 최대심박수와 최초심박수의 차이는 TLC에서 $27.5{\pm}9.2$회/분, FRC 에서 $19.1{\pm}6.0$회/분, RV에서 $26.4{\pm}14.0$회/분으로 FRC에서의 심박수 변화량이 TLC나 RV에서의 변화량보다 유의하게 적었고(각각 p<0.05), 기록상 호흡재개 시점을 전후한 5개씩의 p-p간격의 평균치는 TLC에서 $0.84{\pm}0.10$초와 $0.72{\pm}0.09$초(p<0.025), FRC에서 $0.82{\pm}0.11$초와 $0.73{\pm}0.09$초(p<0.025), RV에서 $0.77{\pm}0.09$초와 $0.72{\pm}0.09$초(p<0.05)로 모두 유의한 차이가 있었다. 결론 : 정상인에서 FRC이상에서 호흡정지시 $SaO_2$의 감소속도는 폐용량/기초대사율과 밀접한 상관관계를 보이고, 호흡정지-재개의 과정에서 생기는 동성부정맥은 FRC상태가 제일 작고 미주신경활성도의 변화가 관여하는 것으로 추정되며, RV에서의 실험결과로 미루어 수면 무호흡증후군 환자들에서 체위, 혹은 복부비만에 기인하는 기능적 잔기량의 감소가 저산소혈증의 정도나 심부정맥의 발생에 미치는 영향에 대한 연구가 필요하고, 수면시의 기능적잔기량을 증가시키는 것이 치료적 유용성이 있는지에 대한 검증도 필요하리라고 사료된다.

• Journal of Chest Surgery
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• 제6권2호
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• pp.131-142
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• 1973

Studies of cardiopulmonary function and acid-base balance were performed on 29 dogs during control period, during oligemic hypotension and following return of blood to the animals. Intravenous morphine and local anesthesia were used. Fifteen of the 29 animals survived the complete experiment. The 14 animals that failed to survive the experimental period died between 15 to 90 minutes after the onset of bleeding. The results were as follows. 1. The heart rate increased after the onset of bleeding and failed to return to control level following reinfusion. Stroke volume decreased markedly after bleeding and failed to recover after return of blood from the reservoir. Cardiac output also decreased during oligemic hypotension and was maintained at this level after re-infusion. Total peripheral resistance decreased significantly immediately after bleeding, however it increased soon over the pre-bleeding level. Central venous pressure decreased after the onset of bleeding and remained at lower level for the rest of the experimental period. Arterial blood pressure, clown to 40-45 mmHg by acute hemorrhage, was elevated near to control level. Left ventricular work decreased tremendously during oligemic hypotension and failed to return to control level with the re-infusion of blood. Hematocrit value showed no significant decrease after bleeding and increased after re-infusion. Hemoglobin decreased after the onset of bleeding and recovered to control value after re-infusion. 2. The respiratory rate fell rapidly after bleeding from 124 to 29 and remained at this lower level for the remainder of the experiment. The tidal volume increased after bleeding and was maintained at this level for the remainder of the experiment. The respiratory minute volume showed no significant changes throughout the experimental period. Oxygen consumption fell lightly in all animals during oligemic hypotension and returned to normal levels following re-infusion. Arterial oxygen content and arterial oxygen saturation decreased following bleeding and the values returned to normal levels after the return of blood from the reservoir The arterio-venous oxygen difference increased after the onset of bleeding. It failed to return to normal values following re-infusion. Arterial $Pco_2$ decreased in all animals after the beginning of the bleeding. Partial pressure of $Co_2$ continued to fall until re-infusion, after which the values returned toward normal. Animals became acidotic. The pH fell to lower level following bleeding. Lactic acid and lactate: pyruvate ratio also increased during same period. Arterial pH and lactic acid failed to return to control value and lactate: pyruvate ratio increased more after re-infusion. Sodium bicarbonate decreased after bleeding and returned to control value following re-infusion.