Knowledge for Anaesthesia students

🌛Methods to fix an endotracheal tube during general anesthesia

🌜Common methods include adhesive tape, twill/cotton tape ties, commercial ETT holders, and special fixation techniques for nasal, prone, or maxillofacial cases.

🧑‍🚒Central cyanosis and peripheral cyanosis both mean a bluish discoloration of the skin or mucous membranes, but they point to different problems.

🧠Antidotes Reference Guide

🤷4-2-1 rule

🙍First 10 kg: 4 mL/kg/hr = 40 mL/hr
🙎Next 10 kg: 2 mL/kg/hr = 20 mL/hr
🙆Remaining 40 kg: 1 mL/kg/hr = 40 mL/hr

🎪SIMV (Synchronized Intermittent Mandatory Ventilation) is a mode of mechanical ventilation used in ICUs and emergency settings to support a patient’s breathing while still allowing them to breathe spontaneously.

🚎Pressure Support (PS) Ventilation Mode — Full Detailed Explanation

🚢Pressure Support ventilation (PS or PSV) is a spontaneous breathing mode used on mechanical ventilators where the patient initiates every breath, and the ventilator assists by delivering a preset positive pressure during inspiration.

🚀It is one of the most commonly used ventilator modes in ICUs, emergency departments, anesthesia recovery, and during ventilator weaning.

🐥Thyromental distance (TMD) and sternomental distance (SMD) are bedside airway assessment measurements used to help predict difficult laryngoscopy/intubation.

🐤Measurement How to measure What it reflects Concerning value
Thyromental distance From thyroid notch to chin/mentum, with neck fully extended and mouth closed Mandibular space for tongue displacement Usually < 6–7 cm suggests possible difficult intubationSternomental distance From upper sternum/manubrium to chin/mentum, with neck fully extended and mouth closed Neck extension + mandibular space Usually ≤ 12.5–13.5 cm suggests higher risk

🦜Easy way to remember:
TMD = Thyroid to Mentum
SMD = Sternum to Mentum

🦣Ventilator modes volume control and pressure control

🦏Volume Control (VC)
You set the tidal volume and respiratory rate. The ventilator delivers that volume using whatever pressure is needed, up to safety limits.

🦛Best for: reliable minute ventilation.
Watch for: high peak/plateau pressures and barotrauma risk.

🦒Pressure Control (PC)
You set the inspiratory pressure and respiratory rate. The ventilator delivers flow until that pressure is reached; the tidal volume varies depending on lung compliance and resistance.

🐫Best for: limiting airway pressure, poor compliance, ARDS-type situations.
Watch for: low tidal volume if compliance worsens.

🦧Feature Volume Control Pressure Control
Set variable Tidal volume Inspiratory pressure
Variable outcome Pressure Tidal volume
Flow pattern Usually constant/decelerating Decelerating
Main advantage Guaranteed volume Pressure limitation
Main risk High airway pressure Inadequate volume

🫀Success rate supine CPR vs prone CPR

🎃Both supine CPR (standard CPR with the patient on their back) and prone CPR (CPR while the patient remains face-down) can generate circulation, but the evidence strongly favors supine CPR as the standard approach whenever feasible.

Prone CPR is CPR performed while a person is lying face down (prone position). It’s mainly used in hospitals when turning the person onto their back would cause dangerous delays or risks — for example during surgery, in ICU patients on ventilators, or when a spinal injury or medical equipment makes repositioning difficult.