供氧與耗氧休克

1、供氧與耗氧Oxygen Supply and Demand1氧運(yùn)輸 oxygen transport (O2T)外呼吸血液循環(huán)組織2氧瀑布 O2 Cascade 氧從空氣進(jìn)入細(xì)胞的線(xiàn)粒體內(nèi)要經(jīng)歷一系列過(guò)程，包括：肺通氣、肺換氣、氧在血液中的運(yùn)輸及氧在組織的釋放四個(gè)步驟。也有學(xué)者把氧運(yùn)輸過(guò)程中，從空氣中氧分壓159mmHg 至細(xì)胞內(nèi)的34mmHg的巨大落差形像地稱(chēng)為氧瀑布。3空氣 上呼吸道 飽和蒸汽壓=47mmHgPiO2=(760-47)0.2094=149mmHg4 肺泡 二氧化碳 - PACO2, 約等于 PaCO2.PAO2 = PIO2 PaCO2/R.- R 為呼吸商.- R 0.8

2、.- PAO2 = 149 (40/0.8) = 100mmHg5動(dòng)脈血氧從肺泡進(jìn)入肺靜脈氧分壓通常下降 5 10 mmHg. PAO2=95mmHg6 毛細(xì)血管 靜脈血毛細(xì)血管和組織間液間的較大的氧分壓差（ 30 mmHg）使得氧氣迅速由血液向組織彌散。7Summary8影響氧運(yùn)輸?shù)囊蛩匦妮敵隽縿?dòng)脈血氧含量 (CaO2)9血紅蛋白與氧的結(jié)合量1g 血紅蛋白最多可結(jié)合1.34ml的氧氣。 (1.39ml when the hemoglobin is chemically pure)如果 Hb=15g/100ml, 最大結(jié)合的氧量 =15*1.34=20.1ml/100ml10在組織內(nèi)釋放的氧量

3、動(dòng)脈血: SaO2=97%, CaO2=19.4ml/100ml混合靜脈血: PvO2=40mmHg, SvO2=75% CvO2=14.4ml/100mlC(a-v)O2=19.4-14.4=5ml/100ml11攝氧率（oxygen extraction,O2ER）The percentage of the blood that gives up its oxygen as it passes through the tissue capillaries is called the utilization coefficient.O2ER=VO2/DO2-normal value is a

4、bout 25%.-during exercise, can increase to 7585%.12氧-血紅蛋白解離曲線(xiàn)13Effects on Oxygen-Hemoglobin Dissociation CurvePaO270090-100604026.7SaO210095-9890755014The causes of a left-shifted oxy-Hb curve(P5027mmHg)Increased hydrogen ionsIncreased CO2Increased temperatureIncreased 2,3-diphosphoglycerate (DPG)16

5、氧供 DO2DO2 是每分鐘供給機(jī)體的氧量。 DO2=(0.0031PaO2+1.38HbSaO2)CODO2=1.38HbSaO2CO如果CO=5L,Hb=15g，DO2=1.38150151000ml/L17氧耗 (VO2)氧耗是每分種實(shí)際消耗的氧量。 VO2=CO(CaO2-CvO2)(ml/min) 正常情況下， 200250ml/min.18氧供需失衡時(shí)機(jī)體的代償機(jī)制CO.血流再分布.細(xì)胞攝氧率.19常用供氧與耗氧的監(jiān)測(cè)DO2=1.38HbSaO2CO (ml/min)VO2=CO(CaO2-CvO2)(ml/min)20測(cè)定Hct及Hb的方法全血細(xì)胞分析儀- Hct、Hb血?dú)夥治鰞x

6、 Hct、Hb血紅蛋白分光光度儀- Hb離心機(jī)Hct21SpO2 monitored by Pulse oximetry since 1980 SO2=O2Hb/(O2Hb+HHb)(%)If R940/R660=1, SO2=85%22Transcutaneous SpO2 monitoringTwo types oximetry: 23Blood gas tension measurementOxygen pressure (PO2) PO2 is to measure directly from a blood sample, usually by using a Clark elect

7、rode.Carbon dioxide pressure (PCO2) PCO2 electrodes work by measuring the change in pH induced when blood equilibrates with a potassium chloride/sodium bicarbonate solution. 24Mixed venous blood oxygen saturation (SvO2)25SvO2 monitoring26連續(xù)頸內(nèi)靜脈血氧飽和度監(jiān)測(cè)27術(shù)中常用的CO監(jiān)測(cè)方法右心飄浮導(dǎo)管Picco(外周動(dòng)脈) FloTrac 傳感器TEE28Vi

8、gileo儀器PreSEP 導(dǎo)管(中心靜脈)ScVO2心排量FloTrac 傳感器(外周動(dòng)脈)29PiCCOUsing PiCCO typically requires insertion of a thermodilution catheter in the femoral or axillary artery instead of a standard arterial line. Any available central venous catheter can be used to inject the solution for the thermodilution analysis.

9、30術(shù)中TEE測(cè)量COM型法短軸縮短率： FAC=(EDA-ESA)/EDA ; 自動(dòng)邊緣識(shí)別系統(tǒng)（ABD）二維Simpson法 SV=LVEDV-LVSDV 多譜勒法 SV=時(shí)間速度積分X橫截面積 三維法 3132氧供需平衡的監(jiān)測(cè)SvO2 60%80%Oxygen extraction ratio (O2ER) O2ER=(CaO2-CvO2)/CaO2Lactic acid 7.3233Gastric tonometry determines intraluminal PCO2 which is assumed to be in equilibrium with PCO2 in the g

10、astric mucosa. Intramucosal pH (pHim) can be calculated by the Henderson-Hasselbach equation using the PCO2 value determined by gastric tonometry and the bicarbonate concentration in arterial blood.Baigorri et al. Critical Care 1997 1:61 doi:10.1186/cc10434決定DO2與VO2的因素DO2VO2HbSaO2COSvO2HbCOSaO235術(shù)中影

11、響氧供的因素DO2CO/Hb100%50%25%36低氧血癥和缺氧hypoxaemia and anoxiaPaO260mmHg, SpO2 低張性缺氧 血液性缺氧 循環(huán)性缺氧 組織性缺氧外呼吸血液循環(huán)組織37氧治療 oxygen therapy/controlled oxygen treatment通過(guò)增加FiO2來(lái)改善低氧血癥。Controlled oxygen treatment is used in those who need supplemental oxygen but not rely on their hypoxic drive to continue breathing.-

12、an increase in PaCO2 show they rely on hypoxic drive. 38The rules of oxygen treatment (1) Give oxygen as much as you can at first, and then reduce it, guided by blood gas measurements.(2) Oxygen treatment will work only if the patient has a patent airway and is breathing. (3) Definitive treatment of

13、 hypoxia depends on the underlying cause. Giving oxygen is a holding measure.39Oxygen therapy PaO2100 beats /min)decrease in pulse pressurecool clammy skindelayed capillary refill slight anxiety. -The decrease in pulse pressure is a result of increased catecholamine levels, which causes an increase

14、in peripheral vascular resistance and a subsequent increase in the diastolic BP. 58Class III hemorrhage (loss of 30-40%) decreased systolic BPMarked tachypnea and tachycardia oliguriaconfusion or agitation -30-40% is the smallest amount of blood loss that consistently causes a decrease in systolic B

15、P. 59Class IV hemorrhage (loss of 40%) Marked tachycardiadecreased systolic BPnarrowed pulse pressure (or immeasurable diastolic pressure)markedly decreased (or no) urinary outputdepressed mental status (or loss of consciousness) cold and pale skin-This amount of hemorrhage is immediately life threa

16、tening. 60低血容量性休克的體征與失血量失血量40%心率100120120140呼吸-2020脈壓- 毛細(xì)血管充盈時(shí)間2s2s測(cè)不到皮膚灌注 收縮壓- 意識(shí)障礙- 61In the patient with trauma, other causes of shock should be considered.cardiac tamponade -muffled heart tones, distended neck veins. tension pneumothorax-deviated trachea, unilaterally decreased breath sounds. sp

17、inal cord injury -warm skin, lack of expected tachycardia, neurological deficits. 62Lab StudiesComplete Blood count (CBC)electrolyte levels (eg, Na, K, Cl, HCO3, BUN, creatinine, glucose levels)prothrombin time, activated partial thromboplastin timeArterial Blood Gases (ABGs)urinalysis (in patients

18、with trauma) ,a urine pregnancy test. - Blood should be typed and cross-matched.63Imaging Studies ultrasonography radiograph Endoscopy - Patients with marked hypotension and/or unstable conditions must first be resuscitated adequately.- Or immediately taking the patient to the operating room.64Gener

19、al monitoringConsciousnessSkin perfusionBlood pressurePulse and respiratory rateurine65Special monitoringCentral venous pressure (CVP)-normal range is 510cmH2O-monitoring and infusion way.-internal jugular vein , subclavicle vein , femoral vein 66Swan-ganz catheterPulmonary Capillary Wedge Pressure

20、(PCWP)-normal range is 615cmH2OCardiac Output (CO)-SVR=(MAP-CVP)/CO*80Mixed venous oxygen saturation (SvO2)- DO2= 1.34 Hb SaO2 CO -VO2=CO(CaO2-CvO2)6768Arterial GasesPaO2 80100mmHg，PaCO2 3644mmHg,pH 7.357.45,BE 3+3,HCO3-2228mmol/L69Lactic acidNormal range: 11.5mmol/LCritical patient:2mmol/LLactic ac

21、id /Pyruvic acid: 10:170Disseminated intravascular coagulation ( DIC) testPlatelet count 3s than the contrastplasma protamine paracoagulation (3P ) test +red cell pieces2%71TEE監(jiān)測(cè)72休克治療的總原則重新建立機(jī)體氧的供需平衡!73外科休克的治療一般緊急治療 補(bǔ)充血容量積極處理原發(fā)病糾正酸堿平衡失調(diào)血管活性藥物的應(yīng)用74一般緊急治療創(chuàng)傷制動(dòng)、止血帶；保持氣道通暢，給氧；體位；盡快建立粗大的靜脈通道；動(dòng)脈置管: 測(cè)壓動(dòng)脈血?dú)?030 1520 75容量復(fù)蘇 Volume resuscitation 晶體液 crystalloids : 生理鹽水 平衡液. 代血漿 Synthetic colloid solutions : 右旋糖苷, 聚明膠肽 , 羥乙基淀粉高滲鹽水 hypertonic saline 3%7.5% NaCl輸血 Blood transfusion：blood loss30%76糾正酸堿平衡失調(diào)根椐血?dú)怆娊赓|(zhì)分析結(jié)果糾正酸中毒，應(yīng)注意寧酸勿堿；糾正電解質(zhì)紊亂。5% 碳酸氫鈉77積極處理原發(fā)病、維持正常凝血功能針對(duì)病因盡快進(jìn)行手術(shù)治療；緊急情況下, 應(yīng)在抗休克的同時(shí)進(jìn)行手術(shù)78使用血管活性藥物