Anesthesia and pain relief

Anesthesia

Can be divided to
1- pre Operative
2-intra Operative
3- Post Operative

Preoperative

Recognition of general medical and specific anaesthetic risk factors facilitates the implementation of pre-emptive measures and improves patient safety& avoid unnecessary delays



Investigation of the general condition of the patient before surgery should be specific according to the general history and clinical signs
So many Investigations in fit people are unnecessary and uneconomic, but indicated tests should be performed as early as possible, preferably before admission
Routine haematological and biochemical screens, with ECG and chest radiography, are prudent investigations in elderly people receiving general anaesthesia for all but not minor surgery.




The saving of a serum sample for transfusion cross-match, a check for hepatitis antigen and HIV is amust now , a sickle-cell screen, if indicated, should not be forgotten
In Iraq hydatid cyst &TB are common disease so chest xray is indicated in most general anesthetic operations

Cardiovascular disease

Uncontrolled hypertension and angina, dysrhythmias and cardiac failure are common reasons for postponement of elective procedures.
Correction of hypertension and ischaemic heart disease is essential and needs to be continued through the operative period, even though the patient may be unable to take oral drugs



Fast atrial fibrillation needs to be controlled before anaesthesia. Symptomatic disorders of sinoatrial conduction require pacemaker insertion before anaesthesia, as do all cases of either Mobitz type 2 second-degree block or third-degree heart block. In an emergency , transvenous temporary pacing wires or external pacing can be used.

PACEMAKER

Modern variable-rate demand pacemakers may require resetting to fixed rate mode, but are generally stable during anaesthesia. However, a cardiological opinion should be sought.
Bipolar diathermy employed if possible and the diathermy plate should be positioned so that the current does not cross the heart or pacemaker wires.




MI
Recent myocardial infarction is a strong contraindication to elective anaesthesia. There is a significant mortality from anaesthesia within 3months of infarction, and elective procedures should ideally be delayed until at least 6 months have elapsed

valvular heart disease

Treatment of any preoperative infections, and appropriate perioperative prophylactic antibiotic cover, to avoid subacute bacterial endocarditis. Care of anticoagulant drugs .
Patients with cardiac disease need careful preoperative evaluation. Much can be derived from a detailed history including exercise tolerance and drug history. & Echocardiography has enabled noninvasive assessment of cardiac function.

BLOOD AND ELECTROLYTES

Electrolyte abnormality (especially hypokalaemia) or anaemia should be corrected and the circulatory volume should be maintained at normal level perioperatively
The presence of an adequate urine output is a useful indicator of adequacy of the circulating volume.



Operative procedures create an increased demand for oxygen due to pain, surgical stress and temperature loss. Patients with cardiac disease may need a period of ٭elective postoperative mechanical pulmonary ventilation after surgery, until the period of raised oxygen consumption has passed.
Careful anaesthetist and surgeon plan such care before surgery

Respiratory disease

In general surgical practice, respiratory infection and asthma are the common problems needing treatment before anesthesia. In chronic respiratory failure, careful attention should be given to 1-perioperative physiotherapy, 2-early mobilization and 3-treatment of infection. 4-measurement of oxygen saturation and 5-blood gas tensions preoperatively give a very useful guide to future values on recovery.
Regional anaesthesia as appropriate is advantageous in respiratory disease



Thoracic surgical procedures demand specific preoperative tests of respiratory function including spirometry and blood gas analysis
Upper abdominal and thoracic procedures are unsuited to regional anaesthesia alone, as positive pressure ventilation under general anesthesia is necessary.



The need for postoperative ventilatory support should be anticipated in patients with respiratory failure , post thoracic operations and in very sever chest infection and bronchial asthma

Gastrointestinal disease

Aspiration of gastric contents carries a high risk of acid pneumonitis, pneumonia and death.
Regurgitation in the presence of a hiatus hernia, or from ‘ the full stomach ’ , may result from emergency (non starved) cases, bowel obstruction or paralytic ileus so indicates mandatory precautions during anaesthesia.

Crash induction

A rapid sequence induction is conducted, in which the patient is preoxygenated for 3 minutes and cricoid pressure is applied from loss of consciousness until the lungs are protected by cuffed tracheal intubation.

Bowel Obstruction

requires preoperative 1-nasogastric aspiration and 2-careful correction of fluid and electrolyte balance before anaesthesia is induced. 3-H2 -receptor blocking agents such as ranitidine are administered if there is an increased risk of regurgitation, ideally at least 2 hours preoperatively.

jaundice

Anaesthesia in the presence of jaundice carries a high risk of renal damage. The anaesthetist should ensure that 1-no hypovolaemia occurs and that a 2-good urine output is present before induction, by the preoperative infusion of intravenous crystalloid solutions. 3- A diuretic agent should only be used if the circulating volume is first assessed to be adequate.

Metabolic disorders

1-Familial porphyria and 2-hyperpyrexia are hereditary metabolic disorders associated with high anaesthetic risks.
3-Phaeochromocytoma is also associated with severe anaesthetic complications. The presence of these disorders requires highly specific preanaesthetic planning.
4-Diabetes and 5-adrenal suppression from steroid therapy are also common metabolic disorders which complicate anaesthesia.




DM
1- Non insulin-dependent diabetic patients on diet and oral hypoglycemic agents will need blood sugar measurement during anaesthesia. An intravenous infusion of glucose may be required if the long-acting hypoglycemic effects persist even if the agent was omitted on the day of surgery. Except for minor surgery, an intravenous infusion of glucose with soluble insulin is likely to be necessary with close monitoring and control of blood sugar levels

Insulin-Dependent Diabetes

2- IDDM always needs preoperative conversion to control with rapidly acting soluble insulin by intravenous infusion on the operative day, and this is continued until the patient has recovered from the operation
The plasma potassium level needs careful control.
The circulating volume should be manipulated independently via a separate infusion of normal saline, blood or colloid.

corticosteroids

Patients who are receiving corticosteroids or who have received them in the past two months require supplementation with hydrocortisone during and after surgery to avoid adrenal insufficiency (Addisonian crisis).