Anaesthesia

8 Anesthesia The First Affiliated Hospital of Zhengzhou University Li

Introdution

Assignment

:

A 、 Clinical anesthesia 1） relief of pain 2） Insure patient safe 3） Produce good conditions for operation 4） prevent and treat 任务 unexpected.

t n e nm g i s as

B、 unite

ICU(intensive care ) monitoring intensive patients C、 First aid and resuscitation D、 Treating pain

Classification of anesthetic techniques *general

Anesthesia *local Anesthesia

*complex Anesthesia

Classification

Preoperative assessment and premeditation e r a p Pre

Table The ASA Physical Status Scale Class 1Ⅰ A normally healthy individual Class 2 Ⅱ A patient with mild systemic disease Class 3Ⅲ A patient with severe systemic disease Class 4Ⅳ A patient with incapacitating systemic disease that is a constant threat to life Class 5Ⅴ A moribund patient who is not expected to survive 24 h with or without operation Class 6Ⅵ Added as a suffix for emergency operation

Purpose: Allay anxiety and fear. Enhance the effect of general anesthetic agent. Reduce in vagal Reduce secretions . .

reflexes.

GA

classification : inhalation anesthesia and intravenous anesthesia.

Agents GA Drugs

common medicine: Inhalational anesthetic agents -Desfllurane 、 Enflurane -Lsoflurane 、 Sevoflurane

Intravenous anesthetic -Thiopentone 、 etomidate

MAC MAC is minimum alveolar concentration of an anesthetic at 1 atmosphere absolute that prevents movement of 50%of the population to a standard stimulus.

Neuromuscular blockade Depolarizing neuromuscular blocking : Suxamethonium chloride Non- Depolarizing neuromuscular blocking :Pancuronium 、 Atracurium 、 Vecuronium

Opioid analgesics

全身麻醉

Complication of general anesthesia Chiefly occur at the Respiratory system Circulation system Complication Central nervous system.

Regurgitation and vomiting

complication preparation for suction apparatus

Should inhalation of gastric contents occur ,treatment with 100%toilet ,steroids and antibiotics should be started immediately Continued IPPV may be required if the resultant pneumonitis is severe GA

Cardiovascular depression • This is likely to occur particularly in the elderly ,the elderly the hypovolaemic or the untreated hypertensive patient .Reducing the lose and speed of injection is recommended in these patients .Infusion of i.v. fluid (e.g500mlcolloidof 1000ml crystalloid solution )is usually successful in restoring arterial pressure

Respiratory depression • Slow injection of an induction agent may reduce the extent of respiratory depression .Respiratory adequacy must be assessed carefully and the anesthetist should be ready to assist ventilation of the anesthetist should be ready to assist ventilation of the lungs if necessary.

ARRHYTHMIAS • Arrhythmias are the most frequently reported critical infirmly .During anesthesia ,bradycardia and tachycardia may be defined as any cardiac rhythm with a rate less than 60 or greater than 100 beat.min-1 respectively. most intraoperative arrhythmias are caused by pharmacological or physiological alterations in autonomic tone and are therefore potentially avoidable of easily treated by correcting the precipitating

Hypotension Causes of hypotension during anesthesia : Decreased venous return Myocardial Vasodilatation Drugs

HYPERTENSION Pre –existing Increased sympathetic tone Drug overdose Other :Hypervolaemia

RESPIRATORY OBSTRUCTION Equipment: Breathing system (Valve malfunction , inking) Tracheal tube (External compression 、 Occlusion of lumen Cuff 、 esophageal or endobronchial intubation)

RESPIRATORY OBSTRUCTION Patient Orpharynx (soft tissue 、 secretions 、 tumor) Larynx (laryngospasm) Trachea (laryngotracheobronchitis) Bronchi (secretions)

HYPOXAEMIA • Hypoxaemia refers to arterial haemoglobin desaturation or reduced arterial oxygen tension ;hypoxia is oxygen deficiency at the tissue level

HYPERCAPNIA

• Hypercapnia refers to carbon dioxide accumulation in the blood .

Other complications • Pain on injection eg.etomidate or propofol • Perivenous injection:Hyaluronidase may be used • Intra-arterial injection : the needle should be left in the artery and 5ml 0.5% procaine

INTUBATION PROBLEMS Unintentional endobronchial intubation Oesophageal intubation Difficult intubation

Causes of difficult intubation • Anaesthetist: Inadequate preoperative assessment Inadequate equipment preparation Inexperience,poor technique Equipment: Malfunction Unavailability No trained assistance Patient : Congenital Acquired