Ch11: Intraoperative Monitoring & Pain Management / CPR（术中监测与疼痛管理、心肺复苏）

Preparatory Mindset

This chapter covers the anesthesia monitoring (how we keep the patient safe during surgery) and pain management (postoperative analgesia) plus CPR (basic & advanced life support — a mandatory skill in the surgery lab, P-4). The lecture (19.7KB) plus the lab CPR deck (7.8KB) are the sources.

Exam mindset: standard monitoring (ECG, SpO2, BP, ETCO2, temp, urine), depth-of-anesthesia monitoring (BIS), neuromuscular monitoring, and the BLS/ACLS chain (compression 100-120/min, 30:2, defibrillation, adrenaline). CPR algorithms are guaranteed OSCE stations.

Core Concepts

1. Standard intraoperative monitoring (MUST KNOW)

- ECG — heart rate & rhythm, ischemia - Pulse oximetry (SpO2) — oxygenation - Non-invasive blood pressure (NIBP) — every 3-5 min - Capnography (ETCO2) — ventilation, confirms intubation, detects malignant hyperthermia/PE (sudden ↓), circuit problems - Temperature — hypothermia/hyperthermia - Urine output — perfusion (≥0.5 ml/kg/h)

- Invasive arterial BP (A-line) — continuous, accurate in shock - Central venous pressure (CVP) — preload - Pulmonary artery catheter / PAWP (rare) — cardiac output - Bispectral index (BIS) — depth of anesthesia (EEG-derived; target 40-60 — prevents awareness) - Neuromuscular monitoring (TOF — train-of-four) — degree of muscle relaxation & reversal adequacy - Echocardiography (TEE) — cardiac surgery - ABG — oxygenation/ventilation/acid-base/electrolytes/glucose - Blood glucose, coagulation (thromboelastography)

• Essential (always):
• Extended (high-risk/complex):

2. Depth of anesthesia & awareness

• Clinical signs (movement, BP/HR response, lacrimation) are unreliable
• BIS 40-60 = adequate depth; <40 = unnecessarily deep; >60 = risk of awareness
• Awareness during GA (rare, ~0.1-0.2%; higher in trauma/obstetric/cardiac) → psychological trauma → consent includes this risk

3. Neuromuscular monitoring — TOF

• Train-of-four (TOF): 4 supramaximal stimuli; count the twitches
• 0 twitches = deep block; 1-2 = surgical relaxation; 4 with fade = residual block (partial reversal); 4 no fade = adequate recovery
• Guides dosing & reversal (neostigmine or sugammadex)

4. Pain management (术后镇痛) — MUST KNOW

- Multimodal analgesia: paracetamol + NSAIDs + opioids + regional blocks — minimize opioid side effects - PCA (patient-controlled analgesia): patient self-administers small opioid doses (lockout interval) — better satisfaction, stable levels - Regional/neuraxial: epidural catheter (thoracic epidural for abdominal/thoracic surgery), peripheral nerve catheters, TAP block, wound infiltration (local anesthetic) - Opioids: morphine, fentanyl, hydromorphone — side effects: nausea, constipation, respiratory depression (worst), sedation, pruritus, urinary retention; monitor sedation score & respiratory rate; naloxone for overdose

• Purpose: relieve pain, reduce stress response, enable early mobilization & recovery (ERAS), prevent chronic pain
• Modes:
• Pain assessment: numeric rating scale (NRS), visual analog scale (VAS); reassess & titrate
• Chronic post-surgical pain prevention: adequate acute control, regional anesthesia, early intervention

5. Basic Life Support (BLS/CPR) — MUST KNOW (lab P-4)

1. Check responsiveness & breathing (no pulse/breathing or gasping → arrest) 2. Call for help / activate EMS; get AED 3. Chest compressions: center of chest, 5-6 cm depth, 100-120/min, allow full recoil, minimize interruptions 4. 30:2 compression:ventilation (2 rescuers); with advanced airway: continuous compressions + 1 breath every 6 s 5. AED: attach, follow prompts — shock if indicated, resume CPR immediately after shock (2 min) 6. Rotate compressors every 2 min (fatigue)

• Chain of survival: early recognition & call for help → early CPR → early defibrillation → post-resuscitation care
• Adult BLS algorithm (2020 AHA):
• Recovery position for unconscious breathing patients
• Pediatric: 15:2 (2 rescuers), 1/3 chest depth; infant: 2-finger compressions / two-thumb technique
• Hands-only CPR for untrained lay rescuers

6. Advanced Life Support (ACLS) — MUST KNOW

1. CPR 2 min → defibrillate (biphasic 120-200 J) → CPR 2 min → adrenaline (epinephrine) 1 mg IV every 3-5 min → defibrillate → CPR → amiodarone 300 mg (then 150 mg) for refractory VF/VT → treat causes

- CPR + adrenaline 1 mg every 3-5 min immediately; no defibrillation; search for reversible causes

- 4H: Hypoxia, Hypovolemia, Hyper/Hypokalemia (& metabolic disorders), Hypothermia - 4T: Tension pneumothorax, Tamponade (cardiac), Toxins, Thrombosis (coronary/pulmonary)

• Shockable rhythms: VF/pulseless VT:
• Non-shockable: PEA/asystole:
• Reversible causes (4H4T — MUST KNOW):
• Post-resuscitation care: targeted temperature management (TTM 32-36°C), treat the cause, coronary angiography for STEMI, glucose control, neuro-prognostication
• Airway: OPA/NPA, bag-mask, LMA, ETT (ETCO2 confirmation); cricothyroidotomy for can't-intubate-can't-ventilate

7. Monitoring in recovery (PACU)

• Modified Aldrete score: activity, respiration, circulation, consciousness, SpO2 — ≥9 before discharge
• Watch for: airway obstruction, hypoventilation, hypotension/hypertension, arrhythmia, bleeding, PONV, hypothermia, pain
• Surgical safety checklist (WHO): before induction, before incision (time-out), before leaving OR

High-Yield Points

• Standard monitoring: ECG, SpO2, NIBP, ETCO2, temperature, urine output
• BIS 40-60 = adequate depth (prevents awareness)
• TOF: 4 twitches no fade = recovery; guide reversal
• PCA: patient-controlled opioid with lockout; watch respiratory depression
• Multimodal analgesia: paracetamol + NSAID + opioid ± regional
• BLS: 100-120/min compressions, 5-6 cm, 30:2, AED, rotate every 2 min
• ACLS: VF/VT → shock + adrenaline 1 mg q3-5min + amiodarone; PEA/asystole → adrenaline, no shock
• Reversible causes 4H4T (hypoxia, hypovolemia, K+/metabolic, hypothermia; tension PTX, tamponade, toxins, thrombosis)
• Opioid overdose: naloxone; respiratory depression = worst side effect
• Post-op pain enables early mobilization (ERAS)

Topic Summary

Intraoperative monitoring: standard (ECG, SpO2, NIBP, capnography/ETCO2, temperature, urine output) plus advanced (arterial line, CVP, BIS 40-60 for depth/awareness, TOF for neuromuscular block). Pain management: multimodal (paracetamol+NSAIDs+opioids±regional), PCA with lockout, epidural/nerve catheters; watch respiratory depression (naloxone). CPR: BLS (compressions 100-120/min, 5-6 cm, 30:2, AED, 2-min rotations) → ACLS (VF/VT: defibrillate + adrenaline + amiodarone; PEA/asystole: adrenaline; treat 4H4T). Post-resuscitation: TTM, treat cause. Recovery: Aldrete score ≥9. WHO surgical safety checklist.