Background

Anesthetic agents administered through inhalation method. One of oldest anesthesia forms, back to early 19^th century.

Inhalation anesthetics used to maintain general anesthesia in surgery. For volatile anesthetics use of vaporizers is recommended due to their liquid nature.

Inhalational anesthetics provide amnesia, immobility, and analgesia effect. It is used in medical procedures/surgeries for pain-free operations.

Inhaled and IV anesthetic are FDA-approved agents for purpose of general anesthesia and sedation in the operation room.

The main uses of inhaled anesthetic agents in ICU are for sedation, bronchospasm, and uncontrolled seizures.

Modern Inhalational Anesthetic agents are:

Halothane

Isoflurane

Sevoflurane

Desflurane

Balanced anesthesia is a combination of anesthetic agents and techniques to achieve ideal sedation level. While combining various agents will give synergistic anesthesia effect.

Development in inhalational and balanced anesthesia will improve safety, efficacy, and patient outcomes.

Indications

for Inhalational Anesthesia:

General Anesthesia

Pediatric Surgery

Emergency Surgery

Maintenance of Anesthesia

Prolonged Surgeries

Controlled Anesthesia Levels

Patients with Difficult IV Access

Pediatric Patients

for Balanced Anesthesia:

Complex Surgical Procedures

Major Surgeries

High-Risk Patients

Cardiovascular Compromise

Orthopedic Surgeries

Laparoscopic Surgeries

Contraindications

for Inhalational Anesthesia:

Respiratory Issues

Patients with Specific Conditions

Malignant Hyperthermia

Significant Liver Disease

First Trimester (Pregnancy)

for Balanced Anesthesia:

Allergies or Sensitivities

Sensitivity to Muscle Relaxants

Severe Renal Impairment

Severe Cardiovascular Disease

Obesity

Psychiatric Disorders

Outcomes

Sevoflurane and desflurane are the best choices for inhalational anesthetics as they give fast onset and quick recovery in short/long procedures.

It activates anesthetic depth control during surgery with quick adjustments and predictable recovery profile.

It improves pain management with fewer side effects for quick recovery, less discomfort, and faster activity resumption is possible.

Equipment required

for Inhalational Anesthesia:

Anesthesia Machine

Breathing Circuit

Endotracheal Tubes or Laryngeal Mask Airway

for Balanced Anesthesia:

Anesthesia Machine

Neuromuscular monitoring device

Breathing Circuit

Patient Preparation

Detailed assessment of patient’s medical history, any current medications, and allergies should be conducted.

Fig. Inhalational anesthesi

Fig. Anesthesia mask

Technique

For Inhalational Anesthesia:

Step 1: Induction:

Administer with volatile anesthetic agent which is delivered through face anesthesia mask.

Step 2: Maintenance:

Surgeons should adjust the concentration of the inhalational agent to maintain the desired depth of anesthesia.

For Balanced Anesthesia

Step 1: Induction:

Administer with intravenous anesthetic agent to induce rapid onset. It should be followed with muscle relaxants if required.

Step 2: Maintenance:

Surgeons should maintain anesthesia with a combination of inhalational and intravenous agents based on the surgery and patient condition.

Complications

Respiratory Complications

Cardiovascular Complications

Malignant Hyperthermia

Neuromuscular complications

Liver Toxicity

Postoperative nausea and vomiting these are commonly noticed adverse effects in inhaled anesthetics.

Malignant hyperthermia is a severe adverse reaction of halothane gas.

Desflurane and isoflurane may irritate the airways of severe asthmatic patients due to pungent odour.

Nitrous oxide should be avoided in craniotomy and intraocular surgeries.

References

Inhalational Anesthetic – StatPearls – NCBI Bookshelf (nih.gov)

References

Inhalational Anesthetic – StatPearls – NCBI Bookshelf (nih.gov)