Clinical Anaesthesiology

1. Clinical Anaesthesiology Qiu Wei Fan Associate professorDepartment of AnaesthesiologyRui Jin HospitalShanghai Second Medical University

2. Local Anaesthetic techniques • Features of local anaesthesia • Methods of local anaesthesia • Complications of local anaesthesia • Regional block equipment • Spinal, epidural, & caudal blocks • Peripheral nerve blocks

3. Preoperative assessment and premedication Purpose • Establish rapport with the patient • Obtain a history and perform a physical examinations • Order a special investigations • Assess the risks of anaesthesia and surgery and if necessary postpone or cancel the date of surgery • Instutite preoperative management • Prescribe premedication and the anaesthesia management

4. Preoperative assessment and premedication Routine preoperative anaesthetic evaluation History • Current problem • Other known problems • Medication history

5. Allergies Drug intolerances Present therapy Prescription Nonprescription Nontherapeutic Alcohol Tobacco Illicit Preoperative assessment and premedication Medication history

6. Preoperative assessment and premedication • Previous anaesthetics, surgery, and obstetric deliverries • Family history • Review of organ systems • Last oral intake

7. Preoperative assessment and premedication Review of organ systems • General • Respiratory • Cardiovascular • Renal • Gastrointestinal • Hematologic

8. Preoperative assessment and premedicationReview of organ systems • Neurologic • Endocrine • Psychiatric • Orthopedic • Dermatologic

9. Preoperative assessment and premedicationPhysical examination • Vital signs • Airway • Heart • Lungs • Extremities • Neurologic examination

10. Preoperative assessment and premedicationLaboratory evaluation • Hematocrit or hemoglobin concentrationAll menstruating womenAll patients over 60 years of ageAll patients who are likely to experience significant blood loss and may require transfusion • Serum glucose and creatinine (or blood urea nitrogen) concentration: all patients over 60 years of age • Electrocardiogram: all patients over 40 years of age • Chest radiogram: all patients over 60 years of age

11. ASA classification • I A normal healthy patient other than surgical pathology- without systemic disease. • II A patient with mild systemic disease – no functional limitations. • III A patient with moderate to severe systemic disturbance duo to medical or surgical disease- some functional limitation but not incapacitating.

12. ASA classification • IV A patient with severe systemic disturbance which poses a constant threat to life and is incapacitating. • V A moribund patient not expected to survive 24 hours with or without surgery. • E If the case is an emergency, the physical status is followed by the letter “E”-, “IIE”.

13. American Society of Anaesthesiologists classification and perioperative mortality rates Class Mortality Rate I 0.06-0.08% II 0.27-0.4% III 1.8-4.3% IV 7.8-23% V 9.4-51%

14. Documentation • Informed Consent • The preoperative note • The intraoperative anaesthesia record • The postoperative notes

15. Local Anaesthetic techniques Features of local anaesthesia • Preservation of consciousness • The quality of early postoperative analgesia • Simplicity of administration • Sympathetic blockade attenuation of the stress response • Minimal depression of ventilation

16. Local Anaesthetic techniques Methods of local anaesthesia • Surface anaesthesia • Local infiltration • Field block • Regional blocks (Spinal, epidural, & caudal blocks) • Peripheral nerve blocks

17. Complications of local anaesthesia • Local anaesthetic toxicity( Systemic toxicity): Cardiovascular, Respiratory， Cerebral and Immunologic • Hypotension • Motor blockade • Pneumothorax • Urinary retention • Neurological complications • Equipment problems

18. Local anaesthetic toxicity Systemic toxicity Cardiovascular: Cardiac dysrhythmia or circulatory collapse is often the presenting sign of local anaesthetic overdose during anaesthesia.

19. Local anaesthetic toxicity Systemic toxicity Respiratory: Lidocaine depresses hypoxic drive. Apnea can result from phrenic and intercostal nerve paralysis or depression of the medullary respiratory center.

20. Local anaesthetic toxicity Systemic toxicity Cerebral: Early symptoms are circumoral numbness, tongue paresthesia, and dizziness. Sensory complaints may include tinnitus and blurred vision.Excitatory signs often precede central nerve system depression.

21. Local anaesthetic toxicity Systemic toxicity Immunologic: True hypersensitivity reactions to local anaesthetic agents- as distinct from systemic toxicity due to excessive plasma concentration- are quite uncommon.

22. Regional block equipment • Spinal needles (26G) • Pencil-point 24G needles • Catheters • Label syringes • A short length of tubing • Nerve stimulators • Local anaesthetic drugs

23. Complications of local anaesthesiaHypotension • Sympathetic blockade • Total spinal blockade • Vasovagal attack • Anaphylactoid reaction

24. Regional block • Subarachnoid block(SAB): Spinal anaesthesia • Extradural nerve block: Epidural anaesthesia may be performed in the sacral(caudal block), lumbar, thoracic or cervical regions.

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40. Regional Block Physiology:Somatic BlackadeVisceral blackadeCardiovascularPulmonaryGastrointestinalLiverUrinary tractMetabolic & Endocrine

41. Physiology effects of SABDifferential nerve blockade • Sympathetic fibres block • sensory block • Motor block

42. Physiology effects of SABRespiratory system • Roots of the phrenic nerves: apnoea • Thoracic level: loss of intercostal muscle activity, decrease in vital capacity, reduction in cardiac output and pulmonary artery pressure, and increased ventilation/perfution imbalance, resulting in a decrease in arterial oxygen tension (PaO2)

43. Physiology effects of SABCardiovascular system • Denervation of the sympathetic outflow tracts (T1-L2): dilatation of resistance and capacitance vessels and results in hypotension • Bradycardia: vasovagal syndrome; block of the cardiac sympathetic fibres

44. Physiology effects of SABGastrointestinal system Sympathetic denervation and unopposed parasympathetic action : a constricted gut with increased peristaltic activity (nausea, retching or vomiting)

45. Physiology effects of extradural block The physiological effect of extradural blockade are similar to those following subarachnoid block.

46. Spinal anaesthesia：Indications • Lower extremities • Hip • Perineum • Lower abdomen • Lumber spineType of surgery: Urology, Gynaecology, Obstetrics and any surgical procedure on the lower limbs or perineum. Urologic endoscopic surgery, Rectal surgery, repair of hip fracture, obstetrics, orthopedic, Inguinal hernia repair, etc.

47. Spinal anaesthesia：Contraindications Absolute:SepsisBacteremiaSkin infection at injection siteHypovolemiaCoagulopathyTherapeutic anticoagulationDemyelating central nerve system diseaseIncreased intracranial pressurePsychosis or dementiaLack of consent

48. Spinal anaesthesia：Contraindications RelativePeripheral neuropathyMini-dose” heparinAspirin or other antiplatelet drugsPrior lumbar spine surgeryChronic back painCertain cardiac lesionsPsychologic or emotional instabilityUncooperative patients Prolonged surgerySurgery of uncertain durationSurgical team resistance to awake patients

49. Patient preparation • Consent • Physical examination • Laboratory Tests • Premedication

50. Equipment & Safety • General Preparation: Monitoring • Administration of GA if necessary • Resuscitation equipment • Regional equipment