醫(yī)學英語學習:休克(2)

Etiology and Classification

病因與分類

There are several mechanisms of organ hypoperfusion and shock. Shock may be due to low circulating volume (hypovolemic shock), vasodilation (distributive shock), primary decrease in cardiac output (both cardiogenic and obstructive shock), or a combination.

器官血流灌注不足和休克可有多種機制引起。休克可能是由于低循環(huán)量（低血容量性休克)、血管舒張（分布性休克)、心排量基本下降（心源性休克和阻塞性休克)，或多種因素結(jié)合。

Hypovolemic shock: Hypovolemic shock is caused by a critical decrease in intravascular volume. Diminished venous return (preload) results in decreased ventricular filling and reduced stroke volume. Unless compensated for by increased heart rate, cardiac output decreases.

低血容量性休克：低血容量性休克是由血管內(nèi)容量嚴重下降引起的。靜脈回流減少（前負荷)導致心室充盈下降和每搏量減少。如果增加心率仍不能代償，心排量就會減少。

A common cause is bleeding (hemorrhagic shock), typically from trauma, surgical interventions, peptic ulcer, esophageal varices, or aortic aneurysm. Bleeding may be overt (eg, hematemesis or melena) or concealed (eg, ruptured ectopic pregnancy).

常見原因有出血（出血性休克)，主要是有外傷、手術(shù)、消化性潰瘍、食管靜脈曲張或主動脈瘤等引起。出血有明顯出血（如嘔血、黑糞癥)或隱性出血（如異位妊娠破裂)。

Hypovolemic shock may also follow increased losses of body fluids other than blood (see Table 1: Shock and Fluid Resuscitation: Hypovolemic Shock Caused by Body Fluid Loss).

除失血外，體液丟失增加后也會出現(xiàn)低血容量性休克（見表1：休克和體液復蘇：體液丟失引起的低血容量性休克)。

Hypovolemic shock may be due to inadequate fluid intake (with or without increased fluid loss). Water may be unavailable, neurologic disability may impair the thirst mechanism, or physical disability may impair access.

低血容量性休克也可能是由于液體攝入不足（伴或未伴體液丟失增加)。缺水、神經(jīng)功能障礙損傷渴感機制，或身體健康狀況影響用水。

In hospitalized patients, hypovolemia can be compounded if early signs of circulatory insufficiency are incorrectly ascribed to heart failure and fluids are withheld or diuretics are given.醫(yī)學全在線m.zxtf.net.cn

住院病人循環(huán)功能不全的早期癥狀若被誤診為心力衰竭，并因此而停止補液或給服利尿劑，可致低血容量加劇。

Distributive shock: Distributive shock results from a relative inadequacy of intravascular volume caused by arterial or venous vasodilation; circulating blood volume is normal. In some cases, cardiac output (and DO2) is high, but increased blood flow through arteriovenous shunts bypasses capillary beds, causing cellular hypoperfusion (demonstrated by decreased O2 consumption). In other situations, blood pools in venous capacitance beds and cardiac output falls.

分布性休克：分布性休克源于因動脈或靜脈擴張引起的血管內(nèi)容量的相對不足，其循環(huán)血量正常。有些病例的心排量（和DO2)高，但通過動靜脈分路使更多的血流繞過毛細管床，造成細胞性血流灌注不足（表現(xiàn)為O2消耗下降)。其他病例則見靜脈容量床血液積聚，心排量下降。

Distributive shock may be caused by anaphylaxis (anaphylactic shock); bacterial infection with endotoxin release (septic shock); severe injury to the brain or spinal cord (neurogenic shock); and ingestion of certain drugs or poisons, such as nitrates, opioids, and adrenergic blockers. Anaphylactic shock and septic shock often have a component of hypovolemia as well.

分布性休克可能原因有：過敏癥（過敏性休克)、細菌性感染伴內(nèi)毒素釋放（敗血癥性休克)、大腦或脊髓嚴重損傷（神經(jīng)性休克)和攝食某些藥物或毒物，如硝酸鹽、類罌粟堿及腎上腺素能神經(jīng)阻斷藥等。過敏性休克和敗血癥性休克也會出現(xiàn)血容量不足。

Cardiogenic and obstructive shock: Cardiogenic shock is a relative or absolute reduction in cardiac output due to a primary cardiac disorder. Mechanical factors that interfere with filling or emptying of the heart or great vessels explain obstructive shock. Causes are listed in Table 2: Shock and Fluid Resuscitation: Mechanisms of Cardiogenic and Obstructive Shock.

心源性和阻塞性休克：心源性休克是緣于初期心臟疾病心排量的相對或絕對減少。影響心臟或大血管充盈或排空的機械因素可說明阻塞性休克的原因。原因見表2：心源性和阻塞性休克機制。