La importancia de la determinación de la deuda de oxígeno en el perioperatorio / The importance of oxygen debt determination in the perioperative period

Resumen: El fenómeno de la deuda de oxígeno (dO2) descrito hace varias décadas en el contexto del ejercicio físico se ha incorporado progresivamente al terreno de la medicina. En particular se ha utilizado durante los cambios hemodinámicos producidos por la cirugía y la anestesia en los pacientes de alto riesgo. La dO2 se definió como el aumento en la cantidad de oxígeno consumida por el organismo inmediatamente después de realizar un ejercicio físico hasta que el consumo se normaliza nuevamente. En el perioperatorio se llega a producir cuando se presenta un desbalance entre la oferta (DO2) y la demanda de oxígeno (VO2) que lleva a hipoxia tisular. El grado de la dO2 tisular se ha relacionado directamente con la falla de órganos múltiples y morbimortalidad perioperatoria. A pesar de los avances en la medicina, aún no es posible prevenir o disminuir la dO2 con la administración de líquidos o con el uso de agentes vasoactivos. Por lo que un retardo o manejo inadecuado de la hemodinámica perioperatoria producirá hipoperfusión e hipoxia tisular afectando los resultados de la cirugía. El conocimiento y la valoración de la dO2 es esencial durante la anestesia del paciente de alto riesgo. Para lograr este objetivo se requiere del uso de índices adecuados que permitan detectar y cuantificar la hipoperfusión tisular y el desbalance entre la DO2 y la VO2. En esta revisión se presentan los conceptos fundamentales de la dO2, su mecanismo, detección y cuantificación; además de las intervenciones para evitarla o disminuirla y las recomendaciones para los anestesiólogos con el fin de asegurar mejores resultados en los pacientes quirúrgicos de alto riesgo.

Abstract: The phenomenon of oxygen debt (dO2) described several decades ago in the context of physical exercise has been incorporated into medicine, particularly during the hemodynamic changes produced by surgery and anesthesia in high-risk patients. dO2 is defined as the increase in the amount of oxygen consumed by the body immediately after physical exercise until O2 consumption returns to normal. In the perioperative period, an imbalance between oxygen supply (DO2) and demand (VO2) could generate dO2. The degree of tissue dO2 has been directly related to multiple organ failure and perioperative morbimortality. Despite advances in medicine, it is not yet possible to prevent or lower the dO2 with fluid administration or vasoactive agents. Delay or inadequate management of hemodynamics could produce tissue hypoperfusion and hypoxia, affecting surgery outcomes. Knowledge and assessing dO2 during perioperative are essential during anesthesia for high-risk patients. Adequate indices are required to detect and quantify tissue hypoperfusion and the imbalance between DO2 and VO2 during anesthesia. This review presents the mechanism, detection, and quantification of dO2. In addition to interventions to avoid or reduce dO2 and recommendations for anesthesiologists to ensure better results in high-risk surgical patients.

Advances of research on oxygen-enhancing nano-delivery system for photodynamic therapy / 中国药科大学学报

@#Photodynamic therapy, a new type of non-invasive treatment, is based on the principle that the photosensitizer excited by laser can transfer energy to oxygen, which generates cytotoxic singlet oxygen and thus induce tumor cell apoptosis or necrosis. As an oxygen-dependent therapy, the antitumor effect of photodynamic therapy is obviously limited by hypoxia environment of solid tumor tissue. Therefore, reversing and improving the hypoxia of tumor tissue can significantly enhance the efficacy of photodynamic therapy. This review focuses on the progress of tumor oxygenation strategy mediated by nano-delivery system, including direct oxygen delivery strategies, catalytic oxygen production strategies, responsive material in situ oxygen supply strategies and microorganism oxygen supply strategies, aiming to improve the antitumor effect of photodynamic therapy. It provides new ideas and new approaches for further study of oxygen-enchancing nano-delivery system for photodynamic therapy.

Long Term Oxygen Therapy in Patients of COPD in Kashmir - Adherence and Barriers to Adherence

COPD is a growing global threat considering its increasing prevalence, morbidity and mortality. The only modality of treatment that has been proven to alter the late course of this disease is the long term oxygen therapy (LTOT). Considering that an increasing number of COPD patients are getting a prescription of LTOT, this study was done to recognize the common barriers that prevent its adequate compliance.METHODSA pre-set questionnaire was administered to patients and their caregivers regarding LTOT prescription, compliance to LTOT and reasons for their poor compliance to LTOT.RESULTS58 COPD patients included in the study completed the questionnaire. Only 12 (21.4%) patients used the recommended oxygen for more than 15 hours per day to give them the therapeutic benefit. 21 (37.5%) patients received recommended advice for the duration of using supplemental oxygen each day from their treating physicians. None of the patients received education about the correct use of using oxygen therapy at home.CONCLUSIONSOxygen usage among patients who have been prescribed home oxygen therapy is far from optimal, and both patient and physician related factors are responsible for it. Thus, the knowledge of major factors responsible for poor compliance of LTOT stresses upon the need for proper education of the treating physician and proper advice and counselling for this treatment modality at the time of prescription, for the patient.

Advances in photodynamic therapy based on tumor hypoxia / 药学学报

Photodynamic therapy (PDT) has attracted wide attention due to its unique advantages such as minimal invasiveness, high efficiency and high selectivity, and its ability to induce anti-tumor immune response. However, the treatment process is heavily dependent on the oxygen content of the treatment site, and the widespread oxygen deficiency in malignant tumors severely limits its efficacy. In addition, PDT-mediated oxygen depletion exacerbates tumor hypoxia, which further reduces its therapeutic effect. In recent years, many researches have been devoted to overcoming this problem. This paper summarized various strategies based on tumor hypoxic PDT in recent years, discussing the advantages and disadvantages of these strategies, and analyzing the main challenges and future directions of PDT in the treatment of tumors, so as to provide references for the in-depth study of photodynamic therapy of tumors.

High-altitude pulmonary oedema: Newer treatment modalities for an age-old problem

Background & objectives: High-altitude pulmonary oedema (HAPE) continues to challenge the healthcare providers at remote, resource-constrained settings. High-altitude terrain itself precludes convenience of resources. This study was conducted to evaluate the rise in peripheral capillary saturation of oxygen (SpO2) by the use of a partial rebreathing mask (PRM) in comparison to Hudson's mask among patients with HAPE. Methods: This was a single-centre, randomized crossover study to determine the efficiency of PRM in comparison to Hudson's mask. A total of 88 patients with HAPE referred to a secondary healthcare facility at an altitude of 11,500 feet from January to October 2013 were studied. A crossover after adequate wash-out on both modalities was conducted for first two days of hospital admission. All patients with HAPE were managed with bed rest and stand-alone oxygen supplementation with no adjuvant pharmacotherapy. Results: The mean SpO2on ambient air on arrival was 66.92�.8 per cent for all patients with HAPE. Higher SpO2values were achieved with PRM in comparison to Hudson's mask on day one (86.08�15 vs. 77.23�09%) and day two (89.94�96 vs. 83.39�93%). The difference was more pronounced on day one as compared to day two. Interpretation & conclusions: Mean SpO2values were found to be significantly higher among HAPE patients using PRM compared to those on Hudson's mask. Further studies to understand the translation of this incremental response in SpO2to clinical benefits (recovery times, mortality rates and hospital stay) need to be undertaken.

Advances in the hypoxia-responsive antitumor drug nanocarriers and tumor hypoxia relieve / 中国药科大学学报

Hypoxia,a salient feature of solid tumors,is often associated with invasiveness,metastasis and resistance to anticancer drugs.The strategies including the use of oxygen-carriers based on hyperbaric oxygen and blood substitutes to transport oxygen into tumors or in situ generation of O2from the tumor microenvironment endogenous H2O2have been explored to relieve the tumor hypoxia and to improve therapeutic efficiency.In addi-tion,it is potential to design hypoxia-responsive nanocarriers based on tumor hypoxia microenvironment to deliver anticancer drugs to the targeted tumor site,thereby improve drug concentrations in targeted site,significantly increase the antitumor efficiency and reduce the side-effects of drugs.This review gives an overview of the advances in relieving tumor hypoxia and hypoxia-responsive nanocarriers for tumor to provide a reference for the research and development of new antitumor drugs.

The effects of DO2-directed hemodynamic management on oxygen metabolism and postoperative prognosis of orthotopic liver transplantation patients / 临床麻醉学杂志

Objective To investigate the effects of different DO2-directed hemodynamic man-agement on postoperative prognosis of orthotopic liver transplantation (OLT)patients with different degrees of liver function insufficiency.Methods Seventy patients (male 48 cases,female 22 cases, aged 37-66 years,ASA grade Ⅲ or Ⅳ)scheduled non veno-venous bypass OLT were divided into two groups (n = 35 each ).The oxygen delivery (DO2 )maintained respectively between 350 ml·min-1 ·m-2 and 500 ml·min-1 ·m-2 (group control)and more than 500 ml·min-1 ·m-2 (group study).After induction of anesthesia,the left radial artery was cannulated,allowing continu-ous blood pressure monitoring as well as serial blood sampling,then the Swan-Ganz catheter was in-serted via the right internal jugular vein to continuously monitor CI and S-vO2 .After anesthesia induc-tion and before operation (T1 ),10 min before anhepatic phase (T2 ),30 min after onset of anhepatic phase (T3 ),30 min after neohepatic phase (T4 )and the end of surgical procedure (T5 ),the SaO2 , PaO2 ,Hb,CI and S-vO2 were recorded to calculate the DO2 ,VO2 and ERO2 .Postoperatively,ICU and hospital length of stay,quality of life (QOL)and 1-5 year survival rate were recorded.Results In the two groups,CI,DO2 and VO2 declined at T3 to a statistically significant degree in comparison with T1 (P <0.05).CI,DO2 and VO2 in group study significantly higher than those of group control (P <0.05).ERO2 in group study was lower than that of group control significantly (P <0.05).ICU and hospital length of stay were significantly shorten in group study in comparison with group control (P <0.05).Survival rate and QOL in group study tended to be slightly higher than those of group control until the end of study period,but there was no significant difference.Conclusion The DO2-directed hemodynamic management can improve prognosis with enhanced DO2 in OLT patients with different degrees of hepatic insufficiency.It has a positive impact on their outcome of shortening ICU stay and the hospitalization days.

Significance for monitoring oxygen delivery and metabolism in circulatory failure situations / 中国小儿急救医学

Failure to deliver sufficient oxygen to the tissues and failure to utilize oxygen in the tissues are essential pathophysiological changes in circulatory failure situations.This is common in all kinds of shocks.Monitoring oxygen delivery and metabolism not only changes the ways to assess the shock but also affects the managements of shocks deeply.Monitoring and controlling global and tissue oxygen delivery and metabolism are goals for circulatory failure assessment and management in the future.

Effect of thoracic epidural anesthesia on oxygen delivery and utilization in cardiac surgical patients scheduled to undergo off-pump coronary artery bypass surgery: A prospective study.

To evaluate the effect of thoracic epidural anesthesia (TEA) on tissue oxygen delivery and utilization in patients undergoing cardiac surgery. This prospective observational study was conducted in a tertiary referral heart hospital. A total of 25 patients undergoing elective off-pump coronary artery bypass surgery were enrolled in this study. All patients received thoracic epidural catheter in the most prominent inter-vertebral space between C7 and T3 on the day before operation. On the day of surgery, an arterial catheter and Swan Ganz catheter (capable of measuring cardiac index) was inserted. After administering full dose of local anesthetic in the epidural space, serial hemodynamic and oxygen transport parameters were measured for 30 minute prior to administration of general anesthesia, with which the study was culminated. A significant decrease in oxygen delivery index with insignificant changes in oxygen extraction and consumption indices was observed. We conclude that TEA does not affect tissue oxygenation despite a decrease in arterial pressures and cardiac output.

Effect of fluid resuscitation on hemodynamics and oxygen in severe trauma patients / 中国综合临床

Objective To observe the effect of fluid resuscitation on hemodynamies and oxygen in severe trauma patients. Methods Parameters of hemodynamic and oxygen metabolism in different fluid volume resuscita-tion in 24 severe trauma patients who were injured on abdominal were measured. Results By fluid resuscitation, as the systolic blood pressure was raised from 80～90 mm Hg(1 mm Hg=0.133 kPa) to 100～120 mm Hg,cardiac in-dex rose from (2.0±0.5 ) L/(min·m2) to (3.2±0.6) L/(min·m2) (P<0.05), systemic vascular resistance index rose from (1857.6±750.2) dyn·s/(cm5·m2) to (3741.5±862.1) dyn·s,/(cm5·m2) significantly (P<0.05). Meanwhile, oxygen delivery index rose from (301.1±74.1) ml/(min·m2) to (554.1±80.0) mL/(min·m2) (P<0.05), and oxygen consumption index also rose (99.7±51.4) mL/( min·m2) to (147.2± 60.1) mL/(min·m2) remarkably (P<0.05), the rate of oxygen expenditure decreased from (33.1±9.1) % to (26.6±8.0) % significantly (P<0.05). Conclusion Large volume resuscitation maybe benefit to the improve-ment of hemodynamics and oxygen metabolism in the emergency resuscitation.

Doses baixas de dobutamina e fluidos no pós-operatório de pacientes de alto risco: efeitos sobre a oxigenação tecidual, resposta inflamatória e morbidade / Low-doses dobutamine and fluids in high-risk surgical patients: effects on tissue oxygenation, inflammatory response and morbidity

JUSTIFICATIVA E OBJETIVOS: A dobutamina é um agente inotrópico com propriedade adrenérgica beta-1 predominante e freqüentemente usado para aumentar o fluxo sanguíneo em pacientes críticos. Dobutamina pode ter um papel no aumento da perfusão esplâncnica, desse modo protegendo esta área de lesão isquêmica. O objetivo deste estudo foi investigar os efeitos de baixas doses de dobutamina (5 mig/kg/min) sobre a oxigenação tecidual, resposta inflamatória e complicações pós-operatória em pacientes de alto risco. MÉTODO: Estudo prospectivo, aleatório, encoberto e placebo-controlado. Cem pacientes cirúrgicos admitidos em Unidade Semi-Intensiva foram avaliados e 82 pacientes foram incluídos, 42 pacientes no grupo controle (solução fisiológica) e 40 no grupo tratamento (5 mig/kg/min) de dobutamina por 24 horas). Os mesmos procedimentos terapêuticos foram usados nos dois grupos. A infusão de líquidos deveria ser realizada em caso de taquicardia ou hipotensão após a infusão de dobutamina, pela possibilidade de hipovolemia. RESULTADOS: O volume total de fluidos administrado foi significativamente maior no grupo dobutamina do que no grupo controle (7351 ± 2082 mL versus 6074 ± 2386 mL, respectivamente, p < 0,05). Saturação venosa central de oxigênio (SvcO2), lactato sérico e proteína C-reativa foram similares em ambos os grupos. Complicações ocorreram em 35 por cento e 50 por cento dos pacientes nos grupos dobutamina e controle, respectivamente (RR 0,70 IC 95 por cento 0,41 - 1,17; NS). CONCLUSÕES: Baixas doses de dobutamina e fluidos após trauma cirúrgico não tiveram efeitos na prevalência de complicações pós-operatória em pacientes cirúrgicos de alto risco.

BACKGROUND AND OBJECTIVES: Dobutamine is an inotropic agent with predominant beta1- adrenergic properties frequently used to increase blood flow in critically ill patients. Dobutamine may have a role in increasing splanchnic perfusion, thereby protecting this area from further injury. We investigated the effects of low doses dobutamine (5 mug/kg/min) on tissue oxygenation, inflammatory response and postoperative complications in high-risk surgical patients. METHODS: Prospective, randomized, blinded and placebo-controlled study. One hundred surgical patients admitted in a step-down unit were evaluated and 82 patients were enrolled, 42 in the control group (saline) and 40 in the treatment group (5 mug/kg/h) during 24 hours. Similar therapeutic goals were applied to both groups. Fluids were given whenever tachycardia or hypotension developed after study drug infusion. RESULTS: The total volume of fluids given was significantly higher in treatment than in control group (7351 ± 2082 mL versus 6074 ± 2386 mL, respectively, p < 0.05). Central venous oxygen saturation (ScvO2), serum lactate and C-reactive protein were similar in both groups. Complications occurred in 35 percent and 50 percent of the patients in the treatment and control groups, respectively (RR 0, 70 IC 95 percent 0.41 - 1.17; NS). CONCLUSIONS: Low-doses dobutamine and fluids after surgical trauma has no effects on the prevalence of postoperative complications in high-risk surgical patients.

Blood tranfusion in critically ill patients: state of the art

Anemia is one of the most common abnormal findings in critically ill patients, and many of these patients will receive a blood transfusion during their intensive care unit stay. However, the determinants of exactly which patients do receive transfusions remains to be defined and have been the subject of considerable debate in recent years. Concerns and doubts have emerged regarding the benefits and safety of blood transfusion, in part due to the lack of evidence of better outcomes resulting from randomized studies and in part related to the observations that transfusion may increase the risk of infection. As a result of these concerns and of several studies suggesting better or similar outcomes with a lower transfusion trigger, there has been a general tendency to decrease the transfusion threshold from the classic 10 g/dL to lower values. In this review, we focus on some of the key studies providing insight into current transfusion practices and fueling the current debate on the ideal transfusion trigger.

A transfusão no paciente crítico vem sendo alvo de discussões recentes considerando seus reais benefícios na redução de morbi-mortalidade e os riscos associados ao procedimento. Nos últimos anos, alguns estudos controlados e randomizados tiveram como objetivo comparar desfechos clínicos entre pacientes que receberam transfusão de maneira mais liberal (hemoglobina alvo em torno de 9 g/dL) e transfusão de maneira mais restritiva (hemoglobina em torno de 7 g/dL). Os resultados demonstram a não superioridade da estratégia liberal comparada com a restritiva. Além disso, em alguns subgrupos de pacientes menos graves ou de menor idade, a transfusão foi associada com piores desfechos clínicos. Os riscos da transfusão de sangue no paciente crítico incluem desde incidência maior de infecções bacterianas, infecções virais, imunodepressão, reações hemolíticas e lesões teciduais inflamatórias, dentre outros. Algumas estratégias vêm sendo analisadas com o objetivo de redução dos riscos da transfusão e incluem leucorredução, implementação de medidas visando minimizar o tempo de estocagem entre outras. Consensos e recomendações recentes sugerem estratégia restritiva transfusional, estimulando uma prática que visa minimizar as perdas sanguíneas, reduzir o limiar crítico da hemoglobina, detectar anemia e tratá-la, e utilizar estratégias à transfusão, como o uso de antifibrinolíticos e da eritropoietina. O objetivo dessa revisão é avaliar à luz dos conhecimentos atuais as evidências em torno da transfusão no paciente crítico em diferentes situações, propondo a racionalização das indicações de transfusão, considerando metas a serem atingidas, com o objetivo de minimizar a morbi-mortalidade do paciente crítico.

The Changes in Delivered Oxygen Fractions Using Laerdal Resuscitator Bag with Corrugated Tubes / 대한마취과학회지

BACKGROUND: In emergency rooms or intensive care units, we have shown delivery of higher fractions of oxygen promptly for respiratory or cardiac arrest patients by using resuscitating instruments, especially the resuscitator bag. Previously we studied the variables affecting the fraction of delivered oxygen (FDO2) under varying ventilating techniques and conditions. In this paper, using corrugated tubes as substitute for reservoir bag, we measured FDO2 and compared two. METHODS: We designed a special wooden box, which held the Laerdal resuscitator bag. We measured the FDO2 with or without reservoir bags and corrugated tubes at various tidal volumes, respiration rates and oxygen flows. RESULTS: With a 500 ml corrugated tube, FDO2 were higher than with a 250 ml corrugted tube but lower than with a reservoir bag. CONCLUSIONS: Corrugated tube is less effective to deliver high fractions of oxygen than the reservior bag, but it is acceptable to use corrugated tube as a substitute for a reservior bag than not to use it at all.

The Effects of Hemodilution on Critical Oxygen Deliveries during Deliberate Hypotension by Esmolol or Sodium Nitroprusside in Dogs / 대한마취과학회지

BACKGROUND: Acute normovolemic hemodilution (ANH) and deliberate hypotension (DH) are methods used for reducing homologous transfusions in cases of massive intraoperative bleeding. Using the technique of combining ANH and DH, we can save more homologous blood than a single use of ANH or DH, but the risk of tissue hypoxia may increase. METHODS: Fourteen male dogs were used for this study and divided into two groups. After performing ANH by 25 ml/kg, mean arterial pressures were reduced to 60 mmHg by sodium nitroprusside (S group) or esmolol (E group). The critical oxygen delivery and the hemoglobin concentration at the critical oxygen delivery were determined by measurements of hemodynamic change, systemic oxygen delivery and systemic oxygen consumption during subsequent hemodilution. RESULTS: After performing ANH by 25 ml/kg, the cardiac output was significantly increased, and systemic vascular resistance and hemoglobin concentration were significantly decreased compared with control values. The critical oxygen deliveries were 179.6 ml/min in the S group and 169.1 ml/min in the E group. There was a difference in mean systemic oxygen consumption between the S group (123.4 +/- 16.7 ml/min) and E group (112.9 +/- 15.4 ml/min) above the critical oxygen delivery point (mean +/- SD). The hemoglobin concentrations at the critical oxygen delivery were 2.6 +/- 0.7 g/dl in S group and 4.0 +/- 1.3 g/dl in E group (mean +/- SD). CONCLSIONS: The critical oxygen delivery during hemodilution under DH by sodium nitroprusside was 179.6 ml/min and by esmolol was 169.1 ml/min. However, esmolol was higher in hemoglobin concentrations at the critical oxygen delivery than sodium nitroprusside. These results suggest thathemodilution under DH by esmolol rather than sodium nitroprusside requires more careful monitoring of systemic oxygen delivery for prevention of tissue hypoxia.

Effects of Thoracic Epidural Anesthesia on Systemic and Myocardial Oxygen Supply/Demand Balance during Coronary Occlusion in Dogs / 대한마취과학회지

BACKGROUND: A thoracic epidural combined with general anesthesia may reduce the oxygen demand of the heart by cardiac sympathetic blockade, but it may also reduce the systemic and cardiac oxygen delivery due to hypoperfusion which is critical to patients with significant coronary lesions. This study was done to investigate the effects of thoracic epidural anesthesia on the systemic and cardiac oxygen supply/demand balance during coronary occlusion in dogs. METHODS: In 10 dogs, the left circumflex coronary artery was occluded, and then thoracic epidural anesthesia was given at the T5-6 or T6-7 level with 5 ml of 0.5% bupivacaine to block T1-T12 through the surgically introduced epidural catheter. Hemodynamic parameters and arterial, mixed venous and coronary sinus blood samples were obtained at baseline and 30 minutes after coronary occlusion. The same parameters were also measured at 30, 60, 90, 120 and 150 minutes after the epidural blockade. An epicardial 2D-echocardiogram was done by a cardiologist at baseline, 30 minutes after occlusion and 1 hour after the epidural blockade. RESULTS: Systemic oxygen delivery (O2 flux) was decreased after epidural anesthesia (p < 0.05), but oxygen consumption (VO2) was maintained throughout the experimental periods. Although the systemic oxygen extraction ratio (O2ER) was not changed, cardiac O2ER was increased at 90, 120 and 150 minutes after epidural anesthesia (p < 0.05). The end-diastolic noncontractile area of the left ventricle was increased, pulmonary capillary wedge pressure was increased 90 minutes after epidural anesthesia and cardiac output was decreased 120 minutes after epidural anesthesia (p < 0.05). CONCLSIONS: In the experimental canine model of coronary occlusion, thoracic epidural anesthesia induces diminished systemic oxygen delivery without deteriorating oxygen supply/demand balance. However, as PsO2 and SsO2 diminished and the noncontractile left ventricular area increased after epidural anesthesia in the setting of acute coronary occlusion, perioperative use of thoracic epidural anesthesia in patients of coronary disease should be done carefully in order not to aggravate myocardial ischemia.

Hypoxia from Erroneous Connection of a Nitrogen Tank for an Oxygen Tank: A case report / 대한마취과학회지

We present a case of hypoxia which occurred during the onset of general anesthesia in a small hospital. It was found that one of the oxygen tank which formed the central pipeline gas supply had been erroneously replaced by a nitrogen tank. Lack of strict observance of Compressed Gas Supply Standards by the gas supplier and the hospital personnel allowed it. We also emphasize that the oxygen analyzer should be counted as an essential monitor in every anesthesia. Oxygen analyzer detects the supply of intraoperative hypoxic gas admixture promptly and effectively.

Hypoxia from Erroneous Connection of a Nitrogen Tank for an Oxygen Tank: A case report / 대한마취과학회지

We present a case of hypoxia which occurred during the onset of general anesthesia in a small hospital. It was found that one of the oxygen tank which formed the central pipeline gas supply had been erroneously replaced by a nitrogen tank. Lack of strict observance of Compressed Gas Supply Standards by the gas supplier and the hospital personnel allowed it. We also emphasize that the oxygen analyzer should be counted as an essential monitor in every anesthesia. Oxygen analyzer detects the supply of intraoperative hypoxic gas admixture promptly and effectively.

A the Study on Relationship Among Diphosphoglycerate (2.3-DPG), Arteriovenous Oxygen Content Difference (A-VO2) and Tissue O2 Delivery of the Patients with Chronic Lung Disease (CLD) / 대한내과학회지

OBJECTIVES: The presence of chronic low oxygen delivery to the tissues (blood flow X Hb concentration X arterovenous oxygen content difference) in patients with chronic lung disease (CLD) leads to a aggravated dyspnea. Therefore, total oxygen delivery to the tissues is a reverse correlation with severity of dyspnea. So far, the treatment of patients with CLD has been limited to only the increase of ventilation and perfusion capacity. However, this study focused on the capacity of oxygen delivery to the tissues in patients with CLD. We measured blood oxygen parameters as one of the extended approaches. METHOD: Simultaneous arterial and venous blood samples from 15 patients with CLD at rest were evaluated for 2.3-DPG, CO-Hb (Carboxy-monohe-moglobin), Met-Hb (methomoglobin), ABGA (Arterial blood gas analysis), VBGA (Venous blood gas analysis) and Hb (Hemoglobin). Smokers and patients with other disease were excluded from the study in order to avoid the factors (2.3-DPG, CO-Hb etc.) which can shift the oxygen dissociation curve. There were 12 men and 3 women, ranging in age from 40 to 75 years. The disease onset varied from 3 years to more than 30 years. RESULTS: 1) As total oxygen delivery to the tissues decreased, Ao2(Arterial oxygen partial pressure) and A-VCb (Arteriovenous oxygen content difference) decreased, while 2.3-DPG increased. Total oxygen delivary to the tissues showed a significant correlation with more A-V and 2.3-DPG than AO2. 2) AO2 had a correlation with A-VO2 but AO2 did not clearly reflect A-VO2. 3) 2.3-DPG activity depended on more A-VO2 than AO2. 4) As A-VO2 decreased, there was more significant relationship among 2.3-DPG, A-VO2 and tissue oxygen delivery. 5) A-VO2 showed a significant reverse correlation with 2.3-DPG as well as Met-Hb % + CO-Hb %. 6) ACO2 (arterial carbon dioxide partial pressure) showed a correlation with 2.3-DPG as well as A-VO2. 7) Arterial PH did not correlate with 2.3-DPG as well as A-V. CONCLUSION: 1) AO2 in patient with CLD correlated with A-VO2 but AO2 did not clearly reflect A-V. 2) Total oxygen delivery (severity of dyspnea) showed a significant correlation with more A-VO2 and 2.3-DPG than AO2. 3) 2.3-DPG activity depended on more A-VO2 than AO2. 4) 2.3-DPG activity had a reverse correlation with A-V in spite that 2.3-DPG shifts the oxygen dissociation curve to the right, because 2.3-DPG shift is secondary change associated with the low oxygen delivery to the tissues, More extensive k prospective investigations are needed to clearly define correlation among A-VO2, 2.3-DPG and prognosis of patients with CLD.

Oxygen dynamics of the patient with septic shock in Qinghai plateau / 中华麻醉学杂志

In order to learn the tissuse perfusion and oxygenization in the patient with septic shock (SS) in Qinghai plateau,25 cases having suffered from SS in Xining,the capital of Qinghai province, were divided into death group (group D) and survival group(group S), and the data of oxygen dynamics, determined by Swan-Ganz cathter and thermodilution methods,were analyzed retrospectively. The results showed that the oxygen delivery (DO_2) and oxygen consumption (VO_2) increased to varying degrees in all of cases;VO_2 was positively correlated with DO_2, and in group D the correlation remained significant during whole duration of disease,but in group S it became unsignificant as DO_2 was above 700 ml?min~(-1)?m~(-2); the oxygen extraction rate decreased markedly in both groups,but much more in group D. These suggest that the insufficient oxygenization of general tissuse in patient with SS results from the dysfunction of oxygen extraction,and increasing DO_2 is helpful for the shock resuscitation except VO_2 is persistently and positively correlatded with DO_2.

The effect of low-dose dopamine on splanchnic oxygen delivery/oxygen consumption on in rabbits SMAO shock / 中华麻醉学杂志

Objective: To study the effect of low-dose dopamine on splanchnic DO_2/VO_2.in rabbit SMAO shock Method:Twenty rabbits were randomly devided into two groups:group A with dopamine,group B as control group. In group A dopamlne was infused at a rate of 5?g?kg~(-1)?min~(-1). SMAO shock model was induced in both groups. Cardiac output index(Cl),portal venous blood flow index (QpvI),mean arterial pressure (MAP),arterial. artiaI and portal venous blood gas analysis.arterial and portal venous serum lactate concentrations(ALT,PLT), total oxygen delivery/oxygen consumption (TDO_2/TVO_2), splanchnic oxygen delivery/oxygen consumption (SDO_2/SVO_2). oxygen extraction ratio(O_2ER) were measured respectively. Result: QpvI, SDO_2,SVO_2 were higher in group A than those of group B (P0.05). CI,MAP, TDO_2/TVO_2 decreased. TO_2ER and SO_2ER increased in both of groups during shock, but without significant differences between both groups. Conclusion: Low-dose dopamine has beneficial effects by increasing portal venous blood perfusion and improving splanchnic oxygenation during SMAO shock in rabbits. but no effects on systemic oxygenation of shock.