Mode of Anaesthesia

What is Monitored Anaesthetic Care MAC?

Monitoring Anaesthestic Care (MAC) refers to the process in which an anaesthestist uses anaesthetic drugs to induce a state of deep sleep in a patient during an endoscopic examination. Throughout the MAC procedure, the anaesthestist closely monitors the patient’s vital signs, such as blood oxygen levels, blood pressure, and pulse, in order to adjust the dosage of anaesthetic drugs. This ensures that the patient enters a stable and deep sleep state while maintaining responsiveness and breathing, thus ensuring the safe and smooth progression of the endoscopy procedure.

Commonly used drugs for MAC include propofol. Since the dosage of anaesthetic drugs used in monitored anaesthetic care is lower compared to general anaesthesia, and the effects are shorter-lasting, patients typically recover quickly and regain consciousness shortly after the MAC procedure.

The benefits of MAC include maintaining a stable level of sedation during anaesthesia, reducing the risk of anaesthesia failure, and preventing the patient from experiencing pain or discomfort during the examination. Moreover, the entire anaesthesia process is managed by specialist anesthestist who closely monitor the patient’s vital signs, ensuring the utmost safety throughout the anaesthesia procedure.

What is Intravenous Sedation IVS?

Intravenous Sedation (IVS) refers to a method of anaesthesia used by doctors to achieve comprehensive anxiety control through the administration of sedative drugs. It is considered a moderate level of sedation. Sedative drugs can suppress the central nervous system and provide varying degrees of sedative effects: ranging from calmness and responsiveness to sound, responsiveness to tactile stimuli, responsiveness to painful stimuli, and even a loss of responsiveness to painful stimuli. This helps reduce patient discomfort during the examination. Patients under IVS during the examination experience a state similar to sleep, characterized by a slowed perception but still retaining awareness. Throughout the anaesthesia process, patients are able to breathe on their own without the need for respiratory support devices. After the examination, the drugs may cause the patient to forget the process of the examination.

The response to IVS varies from person to person, as factors such as a patient’s constitution, health issues, alcohol consumption, and medication history can affect the effectiveness of the drugs. As a result, the sedative effects may differ for each patient and are challenging to predict and stabilize. The required dosage of sedative drugs also varies for each patient, and doctors adjust the dosage based on the patient’s response and vital signs.

Because the depth of anaesthesia with IVS is shallower compared to MAC, patients undergoing IVS during the examination may experience mild discomfort, such as bloating or abdominal pain.


Monitored Anaesthetic Care (MAC)
Intravenous Sedation (IVS)
Mode of AnaesthesiaAdministered under close supervision by an anaesthetist, inducing deep sleep similar to general anaesthesia, ensuring patient comfort during the examination. The most commonly used drug is Propofol, as the dosage of sedative drugs used is lower compared to general anaesthesia, and the procedure is shorter. Patients maintain their own breathing during anaesthesia and rapidly regain consciousness after the examination.The doctor will inject sedative and analgesic medications into the bloodstream, achieving a moderate anaesthetic effect. During the anaesthesia process, the drugs will suppress the central nervous system, reducing patient discomfort and pain. Patients will be in a state similar to sleep during the examination, with a slower perception but still aware, and they will be able to breathe on their own. After the examination, the medication may cause the patient to forget the process of the examination.
DifferencesMonitored Anaesthetic Care (MAC) can control and maintain the level of sedation in a more stable phase, with a lower risk of failure. Typically, when the medical procedure is complete, patients feel less drowsy and can quickly regain consciousness.Due to various factors such as pre-existing health conditions, alcohol consumption habits, medication history, etc., intravenous sedation may have varying effects.

Experienced Specialist Anaesthetists

Adhering strictly to the guidelines of the Hong Kong College of Anesthesiologists, our center ensures that all monitored anaesthetic procedures are led by specialist anaesthetists, without exception, thus ensuring the utmost safety during examinations. All anaesthetists in our centre are certified by the Hong Kong College of Anaesthesiologists. Each doctor holds years of practice and experience, with qualifications that are rigorously recognized. 

Proficient Medical Staff for Emergency Situations

In addition, all of our medical staff members hold certifications in basic life support (BLS) or advanced cardiac life support (ACLS), along with ample experience in handling emergency situations. This ensures their ability to respond effectively to a variety of unexpected circumstances.

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