air alveoli Alveolar capillary ventilation gas exchange external

氧气的获得和利用: air alveoli Alveolar capillary ventilation gas exchange external respiration Gas transport Tissue cells internal respiration

l Concept 运送氧或利用氧发生障碍时，机体发生 功能、代谢、形态结构改变的病理过程. Tissue cells can’t obtain enough oxygen or can’t fully utilize oxygen→ metabolic, functional and structural changes

l Parameters of blood gas 1. Partial pressure of O 2 （PO 2） 2. O 2 capacity （ CO 2 max ） 3. O 2 content（CO 2） 4. O 2 saturation （ SO 2 ）

1. Partial pressure of O 2（PO 2） 溶解在血液中的氧所产生的张力。 The pressure or tension produced by physically dissolved O 2 in the blood. Normal: Pa. O 2: 100 mm. Hg Influenced by: the oxygen pressure in the inhalied air 吸入气氧分压 extra-respiration Normal: Pv. O 2: 40 mm. Hg Influenced by intra-respiration

2. O 2 capacity （CO 2 max） 100 ml 血液中的Hb被氧充分饱和时的最大携氧量 Maximum amount of O 2 that can be combined chemically with the Hb in 100 ml blood. Normal: 20 ml/dl (15 g Hb/100 ml blood ) Influenced by the amount of quality and quantity of Hb

3. O 2 content （CO 2） 100 ml Hb的实际携氧量 The concentration of O 2 in a blood sample Normal: Ca. O 2: 19 ml/dl, Cv. O 2: 14 ml/dl Influenced by the PO 2 and CO 2 max The difference between Ca. O 2 and Cv. O 2 动静脉血氧差: 动脉血氧含量 - 静脉血氧含量

Ca. O 2 -- Cv. O 2 Reflect the oxygen consumption rate of the tissue. 19 ml/dl A O 2 14 ml/dl O 2 5 ml/dl O 2 V

4. O 2 saturation （ SO 2 ） 指Hb结合氧的百分数 Amount of oxygen actually combined with Hb, expressed as a percentage of oxygen capacity. = CO 2 – O 2 of physical solution CO 2 max Normal： Sa. O 2 95% Sv. O 2 75% Influenced by the PO 2 100%

2, 3 -DPG P 50 2, 3 -DPG

Hypoxia l Introduction l Classification, etiology and pathogenesis l Functional and metabolic changes l Factors involved in tolerance to hypoxia l Oxygen treatment and oxygen toxicity

Classification Air External respiration 低张性缺氧 Hypotonic hypoxia Gas transport +Hb circulation 血液性缺氧 Hemic hypoxia 循环性缺氧 Circulator y hypoxia Tissue cells 组织性缺氧 Histogenous hypoxia

低张性缺氧 Hypotonic hypoxia 循环性缺氧 Circulator y hypoxia 血液性缺氧 Hemic hypoxia 组织性缺氧 Histogenous hypoxia

1. Hypotonic hypoxia — Pa. O 2↓ Causes : 1) Pi. O 2↓: high altitude (3000~4000 m) 海拔高度 大气压 Pi. O 2 PAO 2 SO 2 (mm. Hg) % (m) (mm. Hg) 海平面 760 159 105 95 1000 680 140 90 94 2000 600 125 70 92 3000 530 110 62 90 5000 405 85 45 75 6000 366 74 40 70 60018000 270 56 30 50

Normal lung Bronchioles normal Bronchioles constricted PAO 2 normal PAO 2 low Pa. O 2 normal Pa. O 2 low bronchial asthma

gas exchange disorders 肺泡 血液 O 2 CO 2 表面活性物质 上皮细胞 基膜 内皮细胞 Diffusion disorders Ventilation-perfusion mismatching

Bronchioles normal Normal lung PAO 2 normal Increased diffusion distance Pa. O 2 normal Pa. O 2 low pulmonary edema

发绀 (cyanosis)

Characteristics of blood oxygen Types of hypoxia Hypotonic hypoxia Pa. O 2 CO 2 max ↓ 《60 mm. Hg N (or ) 慢性 代偿 Ca. O 2 Sa. O 2 CO 2 (a-v) ↓ ↓ ↓(or N) 发绀 慢性 代偿

Ⅱ. hemic hypoxia Hb量↓ ，质改变→血液携带氧的能力↓或Hb结合的氧不 易释出→组织缺氧 Pa. O 2 Sa. O 2正常 isotonic hypoxemia 1. Causes : (1)Hb量↓—— anemia anemic hypoxia (2)Hb质改变---- carboxyhemoglobinemia CO 中毒 a. Hb + CO O 2 1/10 1/2100 Hb-CO

高铁血红蛋白血症（methemoglobinemia) Hb-Fe 2+ 氧化 还原 Hb. Fe 3+OH 肠源性紫绀 (enterogenous cyanosis 咖啡色 Hb. Fe 3+OH Fe 3+不能携氧 Fe 2+-O 2不能解离

P 50↓：Hb与O 2的亲和力异常 transfusion of depot blood→ 2，3 -DPG↓ OH-↑→p. H↑ RBC内2, 3 -DPG含量第七天可由 4. 8μg/ml降至 1. 2μg/ml

Characteristics of blood oxygen Types of hypoxia Pa. O 2 CO 2 max Ca. O 2 Sa. O 2 CO 2 A-V Hypotonic hypoxia ↓ N or ↓ ↓ ↓ or N Hemic hypoxia N ↓N↑ N ↓ CO， P 50↓ Hb. Fe 3+OH P 50↓

Color of skin anemia —— pale Hb-CO —— 樱桃红 Hb. Fe+3 -OH —— 咖啡色 无发绀 肠源性紫绀 (enterogenous cyanosis

Ⅲ. circulatory hypoxia circulation↓ “hypokinetic hypoxia” 血液循环发生障碍，组织供血量↓ 引起的缺氧. Generalized circulatory deficiency: shock, heart failure Local circulatory deficiency: embolism, AS, thrombosis Ischemic hypoxia : Congestive hypoxia:

v 缺 血 : ischemic hypoxia 动脉 毛细血管 内压↓ 静脉 color of skin: pale v 淤血: 动脉 Congestive hypoxia 毛细血管 内压↑ 静脉 color of skin: cyanosis

Characteristics of blood oxygen Types of hypoxia Pa. O 2 CO 2 max Ca. O 2 Sa. O 2 CO 2 A-V Hypotonic hypoxia ↓ N or ↓ ↓ ↓ or N Hemic hypoxia Circulatory hypoxia N ↓N↑ N ↓ N N

(2) Mitochondria injury: endotoxin, radioactive substances, OFR (3) Vitamin deficiency: Vit. B 1, Vit. PP Result : Cv. O 2↑ →CO 2 a-v↓ Color of skin: Hb. O 2↑→玫瑰色

Characteristics of blood oxygen Types of hypoxia Pa. O 2 CO 2 max CO 2 Sa. O 2 CO 2 A-V Hypotonic hypoxia ↓ N or ↓ ↓ ↓ or N Hemic hypoxia Circulatory hypoxia N ↓N↑ N ↓ N N Histogenous hypoxia N N ↓

临床上常为混合性缺氧 失血性休克 Hb Hemic hypoxia 肺淤血、水肿 Hypotonic hypoxia 循环障碍 Circulatory hypoxia

Hypoxia l Introduction l Classification, etiology and pathogenesis l Functional and metabolic changes l Factors involved in tolerance to hypoxia l Oxygen treatment and oxygen toxicity Hypotonic hypoxia

1. Respiratory system (1) Compensatory response ① Pa. O 2< 60 mm. Hg peripheral chemoreceptor [H+] central chemoreceptor alveolar ventilation↑ Pa. O 2 ↑ Pa. CO 2 ↓（ limit) ② Respiratory rate and depth ↑ → 胸内负压↑ 胸内负压 →静脉回流 ↑ → 心输出量和肺血流量↑ → 有利于氧的摄取和运输

Hypoxia l Introduction l Classification, etiology and pathogenesis l Functional and metabolic changes l Factors involved in tolerance to hypoxia l Oxygen treatment and oxygen toxicity

• Oxygen consumption rate： 发热，甲亢，寒冷，体力活动，情绪激动 • Compensatory ability to hypoxia 疾病，年� ，病程

Hypoxia l Introduction l Classification, etiology and pathogenesis l Functional and metabolic changes l Factors involved in tolerance to hypoxia l Oxygen treatment and oxygen toxicity