Perioperative Pain Management

Question 1

Adverse physiologic effects of postoperative pain

Answer 1

1) Pulmonary System
Atelectasis
Decreased lung volumes
Ventilation-to-perfusion mismatching
Arterial hypoxemia
Hypercapnia
Pneumonia

2) Cardiovascular System
Sympathetic nervous system stimulation
Systemic hypertension
Tachycardia
Myocardial ischemia
Cardiac dysrhythmias

3) Endocrine System
Hyperglycemia
Sodium and water retention
Protein catabolism

4) Immune System
Decreased immune function

5) Coagulation System
Increased platelet adhesiveness
Decreased fibrinolysis
Hypercoagulation
Deep vein thrombosis

6) Gastrointestinal System
Ileus

7) Genitourinary System
Urinary retention

Question 2

Chronic Postsurgical pain is commonly associated with which procedures?

Answer 2

limb amputation (30% to 83%), thoracotomy (22% to 67%), sternotomy (27%), breast surgery (11% to 57%), and gallbladder surgery (up to 56%)

Question 3

Pain (nociception) definition

Answer 3

Pain is described as an unpleasant sensory and emotional experience caused by actual or potential tissue damage or described in terms of such damage

Question 4

Chronic (persistent) pain definition

Answer 4

Chronic pain is pain that has persisted beyond the time of healing. The length of time is determined by the nature of the injury or surgical operation, but the pain is considered to be chronic (persistent) when it exceeds 3 months (or half the days in a 6-month period) in duration

Question 5

Describe the trajectory of an nociception stimuli

Answer 5

Stimuli generated from thermal, mechanical, or chemical tissue damage may activate nociceptors, which are free afferent nerve endings of myelinated Aδ and unmyelinated C fibers. These peripheral afferent nerve endings send axonal projections into the dorsal horn of the spinal cord, where they synapse with second-order afferent neurons. Axonal projections of second-order neurons cross to the contralateral side of the spinal cord and ascend as afferent sensory pathways (e.g., spinothalamic tract) to the level of the thalamus.Along the way, these neurons divide and send axonal projections to the reticular formation and periaqueductal gray matter. In the thalamus second-order neurons synapse with third-order neurons, which send axonal projections into the sensory cortex

Question 6

Is the opioid free technique for postoperative analgesia better than the opioid sparing technique?

Answer 6

A recent review of opioid-sparing versus opioid-free approaches in the perioperative period concluded that although complete opioid sparing is possible in some contexts and procedures, there is no evidence that opioid-free strategies have lasting benefits above and beyond opioid-sparing techniques. In fact, the risk of persistent postoperative opioid use was not found to differ between the opioid-sparing versus opioid-free approaches

Question 7

How ketamine (doses) can be used to reduced postsurgical chronic pain? The benefits associated with ketamine justify its risks?

Answer 7

A preoperative IV ketamine bolus dose of 0.5 mg/kg followed by an intraoperative infusion of subanesthetic (4 to 5 μg/kg/min) ketamine reduces postoperative pain and CPSP.
The benefit of subanesthetic dosing of ketamine also includes a decrease in postoperative nausea or vomiting, with minimal adverse effects.
Subanesthetic ketamine infusions do not cause hallucinations or cognitive impairment. The incidence of side effects, such as dizziness, itching, nausea, or vomiting, is comparable to that seen with opioids