Anesthesia

General Anesthesia Components :

• Analgesia

• Consciousness control (hypnosis, induced)

• Muscle relaxation

• Stability of the autonomic nervous system

Complications of Acute Pain

Pulmonary- respiratory muscle spasm- immobility- suppression of cough- abdominal distension from decreased GI motility- atelectasis from impaired ventilation - mucus plugging from suppression of clearing

mechanisms- V/Q mismatching and hypoxemia- Pulmonary infections

Complications of Acute Pain

Hematologic - increase thrombus formation by increasing blood

viscosity- increasing activity of clotting factors

- increasing platelet aggregation

Cardiovascular Acute rise in HR, BP, Cardiac Output =

increased cardiac work and oxygen consumption.

This could be disastrous for patients with ischemic heart diseases and may lead to myocardial infarction and /or CHF

Complications of Acute Pain

Gastrointestinal - Ileus- Nausea - Vomiting- Decreased bowel motility

Urinary - hypomotility of the urethra and bladder - difficulty with urination

Complications of Acute Pain

Neuroendocrine and Metabolic- increased sympathetic tone & hypothalamic

stimulation- increased catecholamine and catabolic hormone

secretion- increased metabolism and O2 consumption

Complications of Acute Pain

Psychological

- fear - anxiety- depression- frustration

Complications of Acute Pain

- ANESTHESIA - Partial or complete loss of sensation with or with out loss of consciousness as result of disease, injury, or administration of an anesthetic agent, usually by injection or inhalation.

Anesthesia

The main goal is control of the vital functions of the human body in the framework of the surgery in order to protect the patient from the operative stress

HISTORY OF ANESTHESIAPRIMITIVE TECHNIQUES

Club Cerebral concussion achieved by placing a wooden bowl over the head of the patient, and striking this until the patient became unconscious

Strangulation Practiced in Italy as late as the seventeenth century

Alcohol Popular in the eighteenth and nineteenth centuries. Mesmerism In 1779 Friedrich A. Mesmer of Vienna

demonstrated a capacity to bring certain subjects under hypnotic influence. First surgical procedure under mesmerism was performed by J. Cloquet, a French surgeon in 1829. Mesmerism failed because it was less efficient than ether.

Plants Opium, Mandragora (Romans)

HISTORY OF ANESTHESIAINHALATION AGENTS

• Modern Agents• Halothane 1956• Enflurane 1972• Isoflurane 1981• Sevoflurane and

Desflurane

• Nitrous Oxide1799 Davy1824 Hickman1844 Wells• Ether 1842 Long1847 Snow

• Modern Agents• Halothane 1956• Enflurane 1972• Isoflurane 1981• Sevoflurane and

Desflurane

Components of Anesthesia (detailed)

1st Line: Measures designed to diminish body reaction to surgical trauma

- Systemic Analgesia- Local Anesthesia- Control of consciousness - Control of Neuro-vegetative Response (Atar-algesia &

Neurolept-analgesia)- Muscle Relaxation- Artificial/Deliberate Hypotencion- Artificial/Controlled Hypothermia

2nd Line : Measures to control vital functions of the body (respiration, circulation, metabolism)

I. Evaluation of the Patient and Preoprative Preparation

- Preoperative Assessment- Preoperative Medication

II. Equipment PreparationIII. Patient PositioningIV. Immediate Preinduction Period and InductionV. Anesthesia Course and MonitoringVI. Ending Anesthesia and Weaning the Patient

Anesthesia Management

Preoperative AssessmentI. Anesthetic Management Plana. Previous anesthetic experience (malignant hypepyrexia

and adverse r.)b. Allergies (analgesics, antibiotics, radiographic dyes, latex)c. Review patients medical status (extent of the disease)d. Medications (can adversely interact with anesthetics)e. Fasting (to prevent aspiration pneumonitis)f. Physical Examinationg. Laboratory tests (hemoglobin and ECG)h. The surgical procedure (choosing anesthesia and

monitoring techniques) I. The anesthesia management plan

Preoperative AssessmentII. Risk and Anesthesia

ASA Classification of Physical Status

ASA Category Description

Healthy patientMild systemic disease – no functional limitationSevere s. disease – definite functional limitationSevere s. disease that is a constant threat to lifeMonitored patient not expected to survive 24 hours with or without an operation

E Emergency procedure

I.

II.

III.

IV.

V.

Preoperative Medication

Goals for Preoperative Medication– Anxiety relief – Sedation – Amnesia– Analgesia– Drying of airway secretions– Prevention of autonomic nervous system responses– Reduction of gastric fluid volume and increased pH– Antiemetic effects– Reduction of anesthetic requirements– Facilitate induction of anesthesia– Prophylaxis against allergic reactions

Anesthesia Equipment

Anesthesia Equipment

Immediate Preinduction Period and Induction

Airway Management

Airway Management

Airway Management

Airway Management

Anesthesia Course and MonitoringInhalation Anesthesia

Blood/Gas Partitition Coefficient & MAC

Halothane 2.4 0.75% Enflurane 1.9 1.7 % Isoflurane 1.4 1.2 % Nitrous Oxide 0.47

105% Desflurane 0.42 1.0 %

Intravenous Anesthetic Agents

A. Non-Narcotic AnestheticsBarbiturates (Thiopental, Thiamylal, Methoxexital)Benzodiazepines (Diazepam, Midazolam)KetaminePropofol

B. Narcotic Analgetics (Morphine, Fentanil, Alfentanil, Remifentanil, Meperidine)

Muscle RelaxantsFactors that influence use of muscle relaxants as part of general anesthesiaSurgical Procedure

- anatomic location- patient positioning

Anesthetic technique- inhalation v/s injection- airway management (mask vs endotracheal)- ventilation management (spontaneous vs controlled)

Patient factors- body habitus (lean vs obese)- ASA status- Age

Muscle Relaxants ClassificationDepolarizing

- Succinylcholine (5-10 min)Nondepolarizing Long – acting (60 – 90 min)

- d- Tubocurarine- Metocurine- Pancuronium- Doxacurium

Intermediate – acting (20 - 30 min)- Atracurium - Vecuronium

Short – acting (10 – 20 min)- Mivacurium

AnesthesiaMonitoring Requirements & Standards

I. Routine Monitoring– Presence of an Anesthetist – Heart Rate (q 5 min)– Blood Pressure (non-invasive vs invasive)– ECG (continuous)– Ventilation (observing the r. bag; auscultation; ET CO2)– Disconnect Monitors (pressure alarms)– Oxygen analyzer (inspired oxygen concentration)– Pulse Oximeter– Temperature– Diuresis

II. Advanced Hemodynamic Monitoring (CVP, PCWP, CO, etc)

Local / Regional Anesthesia

A. Peripheral Nerve Blockade

B. Spinal and Epidural

Spinal and Epidural AnesthesiaSpinal Cord Anatomy

Spinal and Epidural AnesthesiaPatient positioning

Spinal and Epidural AnesthesiaPatient positioning

Epidural AnesthesiaLumbar and Thoracic Techniques