Anesthetic Assessment - Preoperative History, Examination, and Investigation

Introduction

Anesthesia administration and surgical operations are linked to a complex stress response, which is influenced by the extent of the injury, length of the procedure, amount of intraoperative blood loss, and intensity of the postoperative pain. In the perioperative phase, the negative metabolic and hemodynamic effects of this stress response can lead to various issues. The primary strategy for enhancing outcomes, shortening hospital stays, and reducing overall patient care costs is to reduce the stress reaction to trauma and surgery. According to several large-scale epidemiological studies, inadequate preoperative preparation of the patient may be a significant contributing factor to the main causes of perioperative mortality. Hence, patients who have elective surgery scheduled will go to a preoperative evaluation two to four weeks before their procedure.

What Is Anesthetic Assessment and Screening?

The pre-assessment and screening are required in patients undergoing surgery to reduce perioperative mortality due to co-morbidity. The assessment involves:

Preoperative History: The preoperative history compression of:

1. History of the Presenting Complaint: It briefly explains presenting illness and the surgery that was subsequently scheduled. It is essential to be aware of certain elements of the disease or condition that require surgery; for instance, head and neck surgery may signal the presence of aberrant airway anatomy.

2. Past Medical History:

• Cardiovascular System: Cardiovascular diseases like hypertension require exercise tolerance, a helpful predictor of cardiovascular fitness and, particularly for patients undergoing major surgery. It can help estimate their risk of postoperative problems and the amount of postoperative care required.

• Respiratory System: Respiratory disease may result in acute ischemic conditions during the perioperative period, requiring appropriate oxygenation and ventilation. The ability of patients to lie flat for an extended period when there is the presence of a chronic cough is significant since these criteria may rule out the use of spinal anesthesia. Additionally, the evaluation of signs and symptoms of obstructive sleep apnea is required in the pre-assessment of anesthesia.

• Gastro-Esophageal Reflux (GERD): Aspiration of stomach contents has the potential to be fatal, and the presence of GERD will probably change the anesthetic strategy.

• Endocrine Disorders: These include thyroid and diabetes mellitus.

• Renal Disease: The baseline of renal function is assessed in the pre-assessment phase.

1. Past Surgical History: The anesthetic technique utilized can be considerably affected when the patient is having a repeat treatment, which can also modify the surgical time and ease of operation.

2. Past Anesthetic History: The past anesthetic history is used to confirm any adverse effect (vomiting, and other clinical effects) experienced by the patient in past surgery due to anesthesia.

3. Drug History: A comprehensive drug history is necessary since some medications must be discontinued or altered before surgery. Evaluation of allergies, including those to drugs and non-drugs is mandatory.

4. Family History: It is essential to enquire about any known family history of anesthesia-related issues, even though the majority of hereditary disorders related to anesthesia are exceedingly rare, such as malignant hyperthermia.

5. Social History: It is an inquiry about the patient's history of smoking, alcohol consumption, and any recreational drug usage that plays a major role in anesthesia.

How Is Preoperative Examination or Investigations Done for Anesthetic Assessment and Screening?

Preoperative Examination: Two distinct examinations are conducted in the preoperative examination: the general examination, which evaluates undetected pathology and the airway examination, to predict the difficulty of airway management, e.g., intubation. The general examination involves gastrointestinal, respiratory, or cardiovascular signs, especially any murmurs or heart failure symptoms that have not been evaluated. Before any surgery, an anesthetic evaluation is necessary, including an airway assessment performed by the Mallampati score.

Preoperative Investigations: The type of precise examinations needed will vary depending on various variables, including co-morbidities, age, and the nature of the procedure. The conditions that require additional investigation and management before surgery will depend on the emergency of the procedure. For instance, in diabetic patients with poorly managed blood glucose levels, elective surgery is frequently postponed to enable time for optimization. The most common investigation performed preoperatively are:

1. Blood Test: The screening of blood involves following tests in pre-operative investigations:

• Complete Blood Count (CBC): It is used to evaluate anemia (low red blood cell count) or thrombocytopenia that may need to be corrected before surgery to lower the risk of cardiovascular risk.

• Liver Function Test (LFT): It is essential to monitor liver metabolism and its function which is helpful in perioperative treatment. LFTs assist in medication selection and drug dosage when there is any possibility of liver impairment.

• Clotting Test: Any signs of abnormal coagulation, such as those brought on by iatrogenic factors (such as warfarin), genetic coagulopathies (such as hemophilia A/B), or liver dysfunction, must be identified and treated appropriately during the perioperative period.

• Urea and Electrolytes: Itaids in the evaluation of renal function. The medication choices for anesthesia and postoperative analgesia are based on urea and electrolyte level.

• Other Test: Several disorders require particular tests such as HbA1C or thyroid function checks (TFTs).

1. Cardiovascular Test: When someone is having major surgery or has a history of cardiovascular disease, an ECG (electrocardiogram) is typically advised. It can reveal the underlying heart pathology. On the other hand echocardiogram (ECHO) is widely used in risk assessment. A cardiac murmur, ECG abnormalities, or signs or symptoms of heart failure are considered to be possible considerations.

2. Respiratory Test: Spirometry may help measure the current baseline and predict postoperative pulmonary problems in patients who have a chronic lung disease, such as COPD (chronic obstructive pulmonary disease). If a patient exhibits symptoms and signs of pulmonary disease that have not been recognized, they are also referred for spirometry. Plain film chest radiographs (CXR) are evaluated routinely before surgery.

Conclusion:

The pre-anesthetic assessment enables the systematic identification, categorization, and treatment of perioperative risks. In the appropriate situation, the anesthesiologists should discuss the findings with the patients and educate the patient about anesthesia. Also, for the best results in terms of service, all information regarding anesthesia care should be recorded in the medical records in line with professional and legal requirements.