Summary

In study session III you have learnt

• Circulatory shock means generalized inadequate blood flow through the body, to the extent that the body tissues are damaged because of too little flow, especially because of too little oxygen and other nutrients delivered to the tissue cells such as the brain, heart, liver, kidneys, abdominal viscera and other.
• Three things, the heart, circulating blood volume and the peripheral resistance are needed to maintain a normal blood pressure and tissue perfusion.
• This circulatory response to hypotension is to conserve perfusion to the vital organs (heart and brain) at the expense of other tissues. Progressive vasoconstriction of skin, splanchnic (viscera or internal organ) and renal vessels leads to renal cortical necrosis and acute renal failure.
• Hypotension, a mean arterial pressure less than60 mmHg or systolic blood pressure less than 90 mmHg in previously normotensive persons, is perhaps the hallmark of acute circulatory failure.
• Signs of tissue hypoperfusion cutaneous vasoconstriction, cold, and clammy skin, decreased capillary refill, decrease urine output, confusion lack of cooperation and coma.
• There are different forms of shock with similar pathophysiologic end points, cell death. Hypovolemic shock is caused by decreased effective circulating blood volume. The most common cause of hypovolemic shock is major blood loss, such as occurs with trauma, burn, surgery, or massive gastrointestinal hemorrhage. The circulatory shock caused by inadequate cardiac pumping is called cardiogenic shock. Septic shock is caused by the systemic response to a severe infection. Interruption of sympathetic vasomotor input after a high cervical spinal cord injury, inadvertent cephalad migration of spinal anesthesia or severe head injury may result in neurogenic shock. Hypoadrenal shock occurs from unrecognized adrenal insufficiency to respond to the stress induced by acute illness or major surgery. Anaphylactic shock is an allergic condition in which the cardiac output and arterial pressure often decrease drastically.
• Management of shock depends on the types of shock. General management of shock includes attention to ABC, positioning, oxygen, vascular access, fluid, vasopressors, monitoring and frequent assessment.
• Management of anesthesia in shocked patient begins from preoperative resuscitation and stabilization of patient. Unless the patient requires life-saving surgery it is beneficial to delay surgery while resuscitation is undertaken and hypovolemia, hypoxia and hypothermia treated. Cross match blood and have it available for intra-operative use. Treat shocked patients as you would a patient with a full stomach and severely shocked patients may need ventilation after surgery.