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1.
急性肺血栓栓塞症血气分析的临床意义   总被引:14,自引:0,他引:14  
目的:观察急性肺血栓栓塞症(肺栓塞)时血气指标的变化,评估血气分析在急性肺栓塞诊断和治疗中的作用.方法:资料来源于急性肺栓塞溶栓及抗凝治疗多中心临床试验,回顾性分析107例既往无心肺疾病的急性肺栓塞患者动脉血气结果.结果:呼吸困难是最常见的临床症状,占89.7%(96/107).107例血气分析表明动脉血氧分压(PaO2)正常者19例,占17.8%,PaO2降低的敏感性为82.2%.当两个指标综合考虑时,PaO2降低或动脉血二氧化碳分压(PaCO2)降低的敏感性为91.6%,PaCO2降低或肺泡-动脉血氧分压差[P(A-a)O2]升高的敏感性为98.1%,只有2例患者P (A-a)O2和PaCO2均正常.结论:PaCO2和P(A-a)O2均正常可作为排除急性肺栓塞的重要依据.  相似文献   

2.
目的回顾急性肺栓塞时动脉血气指标Pa O2和血浆D-二聚体的变化,探讨动脉血气指标Pa O2联合血浆D-二聚体测定对急性肺栓塞诊断价值。方法回顾性分析14例急性肺栓塞患者的性别、年龄、高危因素、临床表现,与对照组对照血浆D-二聚体值、动脉血气分析测定结果。结果临床表现为胸痛8例,咯血4例,血压降低3例,咳嗽12例,心悸3例,紫绀2例,单侧下肢水肿2例。肺栓塞组血浆中D-二聚体明显高于对照组,动脉血气分析Pa O2明显低于对照组。肺栓塞组患者中血浆D-二聚体和Pa O2分别检测与血浆D-二聚体和Pa O2联合检测的灵敏度比较,联合检测的灵敏度明显增高。结论血浆D-二聚体和Pa O2联合检测可以提高肺栓塞诊断的灵敏度,对肺栓塞的诊断和有重要意义。  相似文献   

3.
目的 探讨肝肺综合征 (HPS)的临床相关因素和非创伤性诊断。方法 对 74例肝炎肝硬化患者进行B超检查、胸部X线摄片、同步检测血气分析和电解质及肺功能 ,然后计算肺泡气 动脉血氧分压差 [P(A a) O2 ]。结果 P(A a) O2 ≥ 2 .0kPa者发生低氧血症占 6 0 .0 % ( 36 /6 0 ) ,而P(A a) O2 <2 .0kPa者发生低氧血症仅占 7.1% ( 1/14 ) ,两者比较差异有非常显著性 ( χ2 =12 .96 ,P<0 .0 1)。同时低氧血症与患者年龄、病毒感染模式、肝功能Child分级、自发性细菌性腹膜炎、肝性脑病、胸部X线片表现及肺活量等均无明显相关。而P(A a) O2 异常多见于肝功能ChildB、C级和门脉高压患者。结论 仅凭低氧血症和动脉血氧饱和度诊断HPS不确切 ,P(A a) O2 增大≥ 2 .0kPa是非创伤性诊断HPS的有效指标  相似文献   

4.
动脉血气分析鉴别急性呼吸困难   总被引:1,自引:0,他引:1  
目的探讨急性呼吸困难病例血气资料中动脉血氧分压(PaO2)、二氧化碳分压(PaCO2)尤其是肺泡-动脉血氧分差[P(A—a)O2]指标的鉴别诊断意义。方法以肺栓塞(A组)、急性左心衰(B组)、慢阻肺呼衰(C组)各30例病例为研究对象,分析各组血气资料中PaO2、PaCO2和P(A—a)O2差别。结果三组血气资料PH值在正常值范围,均存在不同程度低氧血症和P(A—a)O2增大。慢阻肺呼衰组PaCO2增高(67.883±23.142),肺栓塞组PaCO2接近下限标准(35.773±4.323)。肺栓塞组PaO2(75.843±21.161)与慢阻肺呼衰组(43.280±13.678)相比较,差异有统计学意义(P〈0.01),急性左心衰组PaO2(70.773±17.763)与慢阻肺呼衰组比较,差异有统计学意义(P〈0.01);肺栓塞组与心衰组PaO2相比差异无统计学意义(P〉0.05)。急性左心衰组P(A—a)O2值最大(64.807±39.113),与肺栓塞组(34.818±13.596)相比较,差异有统计学意义(P〈0.01);心衰组P(A—a)O2与慢阻肺呼衰组(30.343±24.222)相比较,差异有统计学意义(P〈0.01);肺栓塞组与慢阻肺呼衰组P(A—a)O2相比较,差异无统计学意义(P〉0.05)。结论利用血气分析等检查,结合临床对鉴别诊断急性呼吸困难病例如肺栓塞、急性左心衰、呼吸衰竭等有很高的实用价值。  相似文献   

5.
肺泡-动脉血氧分差在急诊肺栓塞筛查中的意义   总被引:1,自引:0,他引:1  
目的探讨肺泡-动脉血氧分差(P(A—a)O2)改变在早期肺栓塞筛查的意义。方法以53例急性肺栓塞病例作为观察组,作单样本t检验。结果肺栓塞组血气资料pH值(7.423±0.048)在正常值范围。存在低氧血症(62.9±26.72);PaCO2降低;肺泡-动脉血氧分差(P(A-a)O2增大(37.455±17.226,P〈0.01)。讨论肺泡动脉血氧分差增大,在肺栓塞临床可能性测评表基础上结合D—Dimer等检查可提高急诊早期肺栓塞诊断准确率。  相似文献   

6.
目的探讨红细胞分布宽度(RDW)对重叠综合征的预测价值。方法连续收集2013年6月—2015年1月在暨南大学第二临床医学院住院治疗的20例轻度COPD患者(A组)、20例中重度COPD患者(B组)、20例轻度重叠综合征患者(C组)及20例中重度重叠综合征患者(D组),并根据RDW参考范围将所有患者分为RDW正常组59例和RDW增高组21例。比较A、B、C、D 4组患者一般资料、动脉血气分析指标〔p H值、动脉血氧分压(Pa O2)、动脉血二氧化碳分压(Pa CO2)〕、血浆超敏C反应蛋白(hs-CRP)水平及RDW;比较RDW正常组与RDW增高组患者一般资料、动脉血气分析指标及血浆hs-CRP水平;并分析RDW与Pa O2、血浆hs-CRP水平的相关性。结果 4组患者性别、年龄及p H值比较,差异无统计学意义(P0.05);A组和B组患者Pa O2高于D组,血浆hsCRP水平和RDW低于D组,C组患者Pa CO2低于D组,A组和B组患者RDW低于C组(P0.05)。RDW正常组与RDW增高组患者性别、年龄、p H值及Pa CO2比较,差异无统计学意义(P0.05);RDW增高组患者血浆hs-CRP水平高于RDW正常组、Pa O2低于RDW正常组(P0.05)。Pearson相关分析结果显示,RDW与Pa O2呈负相关(r=-0.265,P=0.018),与血浆hs-CRP水平呈正相关(r=0.258,P=0.021)。结论 RDW可用于重叠综合征患者炎症及气道病变严重程度的初步评估,具有一定的预测价值。  相似文献   

7.
目的通过分析肺栓塞患者临床资料,寻找早期诊断线索。方法确诊肺栓塞患者46例,年龄(70±10)岁,结合临床表现和实验室结果进行回顾性分析。结果98%患者存在高危因素,最常见为深静脉血栓形成(26%),最常见症状为呼吸困难(74%),其次为突然发生的胸痛(13%)和晕厥(13%),86%有血气分析异常,指标以肺泡-动脉血氧分压差>20mmHg(1mmHg=0.133kPa)最为敏感。D-二聚体阳性率为90%。78%有心电图变化,V1,2导联ST-T改变与不典型SⅠQⅢTⅢ较多见。93%有超声心动图异常,多见右心房、右心室肥大,肺动脉压力为(59±11)mmHg。结论突然发生的气促、胸痛等临床表现,结合心电图一过性变化、D-二聚体阳性或动脉血二氧化碳分压降低、肺泡-动脉血氧分压差超过20mmHg异常可为肺栓塞早期诊断提供线索,必要时行超声心动图,可早期确诊。  相似文献   

8.
目的探讨动脉血乳酸清除率与呼吸衰竭患者预后的关系。方法选择呼吸衰竭患者134例,患者入院后给予抗炎、解痉平喘、补液、胸腔穿刺抽气等对症和支持治疗。采用血气生化分析仪检测治疗前(治疗前)及治疗后6、12、24、48、72 h动脉血气,计算治疗后6、12 h动脉血乳酸清除率,采用APACHEⅡ评分系统分别于治疗前和治疗后12 h对患者进行评分。结果治疗后24 h内动脉血乳酸值恢复正常65例、24~72 h动脉血乳酸值恢复正常27例、>72 h动脉血乳酸值恢复正常42例,病死率分别为6.2%(4/65)、33.3%(9/27)、88.1%(37/42),三者相比,P<0.05;前者与后两者的治疗前动脉血乳酸值、Pa O2/Fi O2和APACHEⅡ评分相比,P均<0.05。治疗后存活84例、死亡50例,二者治疗后6、12 h动脉血乳酸清除率、治疗前p H值、治疗前Pa O2/Fi O2、APACHEⅡ评分相比,P均<0.05。治疗后12 h动脉血乳酸清除率≥10%83例、动脉血乳酸清除率<10%51例,病死率分别为25.3%(21/83)、68.6%(35/51)。结论动脉血乳酸清除率与呼吸衰竭患者预后密切相关,动脉血乳酸清除率≥10%时患者预后较好。  相似文献   

9.
目的探讨慢性阻塞性肺疾病急性加重期(AECOPD)伴重度呼吸衰竭患者有创机械通气成功撤机拔管的影响因素。方法选取2010年3月—2015年3月内蒙古医科大学附属医院收治的AECOPD伴重度呼吸衰竭患者74例,均行有创机械通气治疗,其中49例患者成功撤机拔管(成功组),25例患者撤机拔管失败或死亡(失败组)。自制病例资料收集表,收集内容包括一般临床特征(性别、年龄、病程及吸烟史)、实验室检查指标{插管前动脉血气分析指标〔动脉血氧分压(Pa O2)、动脉血二氧化碳分压(Pa CO2)、血氧饱和度(Sa O2)、p H值〕及插管前和拔管时血常规检查指标〔血红蛋白(Hb)、白细胞计数(WBC)、中性粒细胞分数(NEU%)〕、C反应蛋白(CRP)、清蛋白(ALB)}及机械通气指标〔多脏器功能衰竭(MODS)发生率和通气时间〕,采用多因素logistic回归分析筛选AECOPD伴重度呼吸衰竭患者有创机械通气成功撤机拔管的影响因素。结果 74例患者撤机拔管成功率为66.2%,病死率为20.3%。单因素分析结果显示,两组患者性别、病程、吸烟史阳性率和插管前p H值、Pa O2、Pa CO2、Sa O2、WBC、NEU%、CRP及ALB水平比较,差异均无统计学意义(P0.05);成功组患者年龄小于失败组,插管前Hb及拔管时Hb和ALB水平高于失败组,拔管时WBC、NEU%、CRP水平及MODS发生率低于失败组,通气时间短于失败组(P0.05)。多因素logistic回归分析结果显示,年龄〔OR=1.733,95%CI(1.043,2.397)〕、插管前Hb水平〔OR=1.874,95%CI(1.142,3.212)〕、拔管时NEU%〔OR=2.163,95%CI(1.022,3.672)〕、拔管时ALB水平〔OR=2.730,95%CI(1.374,3.984)〕、MODS〔OR=2.032,95%CI(1.123,3.957)〕及通气时间〔OR=1.893,95%CI(1.033,3.163)〕是AECOPD伴重度呼吸衰竭患者有创机械通气成功撤机拔管的影响因素(P0.05)。结论年龄、感染、营养状况、MODS及通气时间是AECOPD伴重度呼吸衰竭患者有创机械通气成功撤机拔管的影响因素。  相似文献   

10.
目的探究雾化吸入布地奈德联合N-乙酰半胱氨酸(NAC)治疗特发性肺纤维化(IPF)的临床疗效。方法选取2008年5月—2013年10月恩施土家族苗族自治州民族医院收治的IPF患者80例,随机分为对照组和治疗组,每组40例。对照组患者采用常规治疗联合布地奈德雾化吸入治疗,治疗组患者在对照组基础上联合NAC口服治疗,两组患者均治疗3个月。观察两组患者临床疗效、胸部CT改善情况及不良反应发生情况,治疗前后呼吸困难评分、血气分析指标{动脉血氧分压(Pa O2)、动脉血二氧化碳分压(Pa CO2)、血氧饱和度(Sa O2)以及肺泡-动脉血氧分压差〔P(A-a)O2〕}及肺功能指标〔肺总量(TLC)、用力肺活量(FVC)、第一秒用力呼气容积(FEV1)/FVC、最大自主通气量(MVV)、肺一氧化碳弥散量(DLCO)〕。结果治疗组患者有效28例、无效12例;对照组患者有效21例、无效19例;治疗组临床有效率(70.0%)高于对照组(52.5%)(P0.05)。两组患者治疗前呼吸困难评分比较,差异无统计学意义(P0.05);治疗后治疗组患者呼吸困难评分低于对照组(P0.05)。两组患者治疗前Pa O2、Pa CO2、Sa O2、P(A-a)O2、TLC、FVC、FEV1/FVC、MVV、DLCO比较,差异无统计学意义(P0.05);治疗后两组患者Pa CO2、Sa O2比较,差异无统计学意义(P0.05);治疗后治疗组患者Pa O2、P(A-a)O2、TLC、FVC、FEV1/FVC、MVV、DLCO均高于对照组(P0.05)。治疗后治疗组患者胸部CT改善情况优于对照组(u=2.355,P=0.009)。对照组患者不良反应发生率为10%,治疗组为20%,差异无统计学意义(P0.05)。结论雾化吸入布地奈德联合NAC能明显改善IPF患者临床症状、血气分析指标、肺功能等,临床疗效确切且不良反应轻。  相似文献   

11.
The alveolar to arterial difference of oxygen [(A-a)DO2] depends on variables such as ventilation, cardiac output, respiratory exchange ratio and arterial PO2. The arterial PO2 itself depends on the ventilation to perfusion ratio (V/Q) pulmonary shunt, (a-v) O2 difference, and the metabolic status of the patient. When the alveolar-ventilation is normal, the (A-a)DO2 reflects gas exchange abnormalities and when the alveolar-ventilation is increased, the (A-a)DO2 can increase because of a decrease in PaCO2. The factors capable of altering the alveolar to arterial oxygen difference were investigated in ninety patients with pulmonary disease: (pulmonary embolism, lung fibrosis and chronic obstructive lung disease), both at rest and during exercise. At rest when alveolar ventilation was increased, the (A-a)DO2 broadened due to the decrease in PaCO2. During exercise the (A-a)DO2 also increased and the PaCO2 was not significantly modified, therefore admixture it is the result of an increase in the proportion of venous. The difference between the mixed venous and arterial PO2 decreased due to alveolar hypoventilation reducing in consequence the (A-a)DO2. We conclude that in the group studied the increase in the (A-a)DO2 is mainly due to V/Q imbalance at rest and during exercise.  相似文献   

12.
BACKGROUND: Arterial blood gas analysis (BGA) remains a first-step diagnostic approach in patients with suspected pulmonary embolism (PE). The aim of this study was to evaluate BGA parameters in elderly patients with suspected pulmonary embolism for diagnosis and 14-day prognosis. METHODS: We performed a retrospective cohort observational study of 6 years (1994-1999) in a 60-bed acute geriatric ward of University Hospital in Siena, Italy. Room air arterial oxygen partial pressure (pO2), arterial carbon dioxide partial pressure (pCO2), pH, arterial oxyhemoglobin saturation (SO2), and alveolar-arterial oxygen gradient [D(A-a)O2] were performed on hospital admission of 75 patients with confirmed PE (CPE) and were compared with data from 43 patients with unconfirmed PE (UCPE). The same parameters of 54 CPE surviving patients were compared with 21 CPE nonsurviving patients. RESULTS: Significantly lower PO2 and SO2, and higher DA-aO2 were found in CPE patients. Respiratory alkalosis was found in one third of the patients in both groups (no significant difference). In the CPE group, there was a significantly lower SO2 in nonsurviving patients, without significant differences for the other parameters. Metabolic acidosis was significantly more frequent in nonsurviving patients. CONCLUSION: More severe hypoxemia, oxyhemoglobin hyposaturation, and higher D(A-a)O2 are associated with the diagnosis of PE in elderly patients. Respiratory alkalosis is less frequent than in younger patients, and metabolic disorders are negative prognostic indicators.  相似文献   

13.
It has been reported that the finding of a normal PaO2 level on arterial blood gas analysis does not exclude the diagnosis of acute pulmonary embolism. We wished to determine whether a more thorough evaluation of the blood gases would prove more helpful; specifically, whether it is possible for a patient with acute pulmonary embolism to have a normal alveolar-arterial (A-a) oxygen gradient. We studied this question in a patient population in which the diagnosis was definitively made via pulmonary arteriography. Sixty-four patients met all study criteria. In these patients, the A-a gradient ranged from 11.6 to 83.9 mm Hg (mean, 41.8 mm Hg). In three patients, the A-a gradient was normal for age. We conclude that a normal A-a oxygen gradient does not exclude the diagnosis of acute pulmonary embolism, and should not preclude further diagnostic procedures if there is a high index of suspicion.  相似文献   

14.
Pulmonary hypertension secondary to minor pulmonary embolism   总被引:1,自引:0,他引:1  
The response of pulmonary arterial pressure to minor degrees of pulmonary embolism was examined in 18 patients with embolic occlusion of less than 25% of the pulmonary vascular bed. Patients with pulmonary embolism were compared to normal controls matched for age and sex and to patients with a variety of acute pulmonary disorders without pulmonary embolism. Patients with pulmonary embolism and patients with other acute pulmonary diseases had significantly higher pulmonary arterial pressures and significantly lower values for arterial oxygen tension (PaO2) than did normal subjects. The degree of pulmonary hypertension correlated with the PaO2. Pulmonary hypertension occurring after minor degrees of pulmonary embolism may be a response to mild arterial hypoxemia.  相似文献   

15.
Agents that inhibit nitric oxide synthesis augment hypoxic pulmonary vasoconstriction. In an animal model of unilateral alveolar hypoxia, we investigated the hypothesis that endogenous endothelium-derived relaxing factor/nitric oxide opposes hypoxic pulmonary vasoconstriction and supports blood flow to hypoxic alveoli, resulting in a reduction in arterial oxygen tension (PO2). In pentobarbital-anesthetized rabbits, unilateral alveolar hypoxia was produced by ventilation of one lung with 100% oxygen and the other with 100% nitrogen (O2/N2). NG-Nitro-L-arginine methyl ester (0.03 followed by 1.0 mg/kg i.v.) resulted in dose-dependent decreases in the percent of pulmonary blood flow to the N2-ventilated lung and increases in arterial PO2. L-Arginine (1 mg.kg-1.min-1 i.v.) prevented the NG-nitro-L-arginine methyl ester-induced redistribution of blood flow away from hypoxic alveoli and improvement in arterial PO2. Indomethacin (5 mg/kg i.v.) administered during O2/N2 ventilation resulted in a reduction in the percentage of total blood flow to the hypoxic lung and an increase in arterial PO2. However, NG-nitro-L-arginine methyl ester administered in the presence of indomethacin caused additional diversion of blood flow away from the hypoxic lung. The magnitude of the changes suggests that the endothelium-derived relaxing factor/nitric oxide system has the capacity to make a greater contribution than products of cyclooxygenase-mediated arachidonic acid metabolism in supporting blood flow to hypoxic alveoli in the rabbit.  相似文献   

16.
The effect of exercise on pulmonary gas exchange and oxygen transport was studied in 42 patients with COPD. Arterial PO2 increased and arterial PCO2 did not change significantly in 25 patients (group A). Arterial PO2 decreased and arterial PCO2 increased in the remaining 17 patients (group B). In group A, P(A-a)O2,Qs/Qt decreased remarkably, oxygen transport and oxygen extrication increased significantly during exercise when compared with that of group B. Our data imply that PO2 changes of COPD patients during exercise may be related to the patient's ventilation, pulmonary gas exchange and mixed venous PO2 levels.  相似文献   

17.
The determinants of hypoxemia were studied in 10 patients with acute pulmonary embolism demonstrated by pulmonary angiography. Two patients were mechanically ventilated, and in the 8 who breathed room air spontaneously, the mean arterial PO2 was 61.5 mmHg. Measurements of the distributions of ventilation (VA) and perfusion (Q) against VA/Q ratios by the multiple inert gas infusion technique demonstrated an increase in VA/Q inequality. The major part of pulmonary blood flow was distributed in a mode near to, or slightly above, a VA/Q ratio of 1. The cumulative fraction of blood in true shunt and low VA/Q mode (VA/Q less than 0.01) was 9.1%. For a small part of the AaDO2 (13%), an oxygen diffusional component was found. The remaining hypoxemia was due to the fall in the mixed venous PO2 (PVO2), irrespective of its cause: low cardiac output, low hemoglobin concentration, high oxygen consumption, low P50. The fall in PVO2 led to a fall in end-capillary blood PO2 in both shunt or ventilated and perfused units. We conclude that the major determinant of hypoxemia in these patients suffering from acute pulmonary embolism is the fall in PVO2. This is enhanced by a moderate increase in the fraction of blood flowing through low VA/Q units. Diffusion impairment plays only a minor role.  相似文献   

18.
Today a large group of patients with pulmonary embolism is still undetected because this disease is not suspected. We evaluated the role of routine clinical procedures such as history, chest x-ray, electrocardiogram and blood gas analysis in the diagnosis of this disease. We studied 177 patients sent to our observation with suspicion of pulmonary embolism, which was later confirmed in 97 and excluded in 80. Prolonged immobilization, surgical procedures and deep vein thrombosis are the most frequent predisposing factors (P less than 0.05 or less) in patients with pulmonary embolism with respect to patients with unconfirmed suspicion of embolism. Among symptoms and signs, pleuritic chest pain, sudden onset of dyspnea, tachypnea, fever, enlarged jugular veins, enhanced pulmonary component of the second heart sound, pulmonary systolic murmur and basal hypophonesis were the most frequent signs (P less than 0.005 or less) in patients with embolism. Among radiographic signs "sausage" descending pulmonary artery, diaphragmatic elevation, pulmonary infarction, Westermark sign and azygos vein enlargement were more frequent (P less than 0.05 or less) in patients with embolism with respect to patients with unconfirmed suspicion of embolism. Among electrocardiographic signs, tachycardia, P-R segment displacement and negative T wave in V1-V2 were more frequent in patients with embolism with respect to patients with unconfirmed suspicion of embolism (P less than 0.05 or less). PO2, standard pO2 and pCO2 were significantly lower (P less than 0.001) in patients with embolism. After discriminant analysis of the whole data set most patients were correctly classified as embolic (90/97) and non-embolic (75/80).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

19.
Pulmonary tumor embolism is a common finding at autopsy but is generally perceived as a difficult diagnosis to make ante mortem. After a retrospective review of 164 reported cases of pulmonary tumor embolism, we identified a typical profile of clinical, laboratory, and imaging features that may permit confident clinical diagnosis in most patients with this condition. The clinical features include a documented or suspected underlying malignancy, acute to subacute onset of dyspnea, and signs of cor pulmonale. Supportive laboratory features are hypoxemia or increased alveolar-arterial oxygen gradient, and invasive or noninvasive evidence of pulmonary artery hypertension. Typical imaging findings are normal chest radiographs; multiple, subsegmental, peripheral perfusion defects on ventilation-perfusion lung scans; and delayed filling with or without subsegmental filling defects but without a thrombus on pulmonary angiogram. Radiolabeled monoclonal antibody imaging and pulmonary microvascular cytology sampling techniques are promising diagnostic tests for early diagnosis of pulmonary tumor embolism.  相似文献   

20.
Increasing hypoxia with altitude ascent is a potentially serious problem for patients with hypoxemic chronic airway obstruction (CAO) at sea level. We developed a hypoxia-altitude simulation test (HAST) to assess acute cardiopulmonary responses to the inhalation of hypoxic gas mixtures (equivalent to the inspired oxygen tension (PO2) present at 5,000, 8,000, and 10,000 feet above sea level) alone and in combination with supplemental oxygen (O2). Twenty-two subjects with stable normocapnic CAO were studied at sea level with a computer-based system that measured on-line, breath-by-breath resting ventilatory and gas exchange variables. Subjects breathed 20.9% (baseline), 17.1, 15.1, 13.9, and 20.9% (recovery) O2, and measurements were obtained once a "steady state" was reached at each level. Steady-state arterial PO2 (PaO2) and O2 saturation, alveolar PO2, and alveolar-to-arterial PO2 gradient decreased markedly during successive hypoxic levels, whereas arterial carbon dioxide tensions decreased only modestly. Minute ventilation and heart rate during 13.9% O2 increased only 12 and 10% above baseline. Ten subjects had asymptomatic cardiac arrhythmias during the HAST. Supplemental O2 significantly improved nearly all physiologic indexes. Sea level PaO2 best predicted acute, resting altitude PaO2. Sea level PaO2 values of 68 and 72 mmHg successfully classified more than 90% of the subjects with a PaO2 greater than 55 mmHg at 5,000 feet and a PaO2 greater than 55 mmHg at 8,000 feet, respectively. A regression equation and nomogram were derived to estimate PaO2 at altitudes between 5,000 to 10,000 feet in patients with normocapnic CAO.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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