Which of the following statements given below is incorrect regarding CPR?

Chest compression rate 100-120/min

Depth of chest compression up to 5-6 cm

Which among the following modes of ventilation has the highest risk of a patient developing respiratory alkalosis?

Controlled Mandatory Ventilation (CMV)

Synchronous Intermittent Mandatory Ventilation (SIMV)

Which of the following is most associated with respiratory alkalosis?

Assisted control mode ventilation

A 40–year female has to undergo incisional hernia surgery under general anaesthesia. She complains of awareness during her past cesarean section. Which of the following monitoring techniques can be used to prevent such awareness ?

Transesophageal echocardiography

During intraoperative period following capnograph waveform is seen. What does it signify.

Return of spontaneous ventilation

The most appropriate circuit for ventilating a spontaneously breathing infant during anaesthesia?

Jackson Rees modification of Ayre's T piece

Mapleson C or Waters to and fro canister

Anesthesia Ventilators for FMGE: High-Yield Anesthesiology Lessons

Basics & Components - Breath Guardians 101

Anesthesia ventilators: Automate patient breathing, delivering set tidal volumes ($V_T$) or pressures.
Principle: Positive pressure ventilation (PPV); overcomes airway resistance & elastic recoil.
Components:
- Driving gas mechanism: Bellows (ascending/descending) or piston.
- Breathing circuit: Inspiratory/expiratory limbs, Y-piece, unidirectional valves.
- Control valves: APL (Adjustable Pressure Limiting), PEEP (Positive End-Expiratory Pressure).
- Fresh Gas Decoupling (FGD) prevents barotrauma from O₂ flush.
Key Formulas:
- $Compliance = \Delta V / \Delta P$ (Lung distensibility)
- $Resistance = \Delta P / Flow$ (Airflow opposition)

⭐ Ascending bellows (standing) collapse upon circuit disconnection, providing a visual alarm - a key safety feature. 📌 "Stand up for Safety!"

Ventilation Modes - Control Freaks & Helpers

Mode	Parameters	Pros	Cons	Use Cases
VCV	Set $V_t$, RR, PEEP, $F_iO_2$. $P$ varies.	Guaranteed $V_t$, $MV$.	Risk barotrauma (high $P_{peak}$).	ARDS (cautious), precise $V_t$.
PCV	Set $P_{insp}$, RR, PEEP, $F_iO_2$, I:E. $V_t$ varies.	Limits $P_{peak}$, decelerating flow.	Variable $V_t$.	ARDS, high $P_{peak}$ risk, lap.
SIMV	Set $V_t$/$P_{insp}$, RR, PEEP, $F_iO_2$, PS.	Spontaneous breaths, aids weaning.	Potential ↑ WOB.	Weaning, some resp. drive.
PSV	Set PS (5-20 cmH₂O), PEEP, $F_iO_2$. Pt triggered.	Pt comfort, supports spont. breaths, weaning.	No backup rate, variable $V_t$.	Weaning, SBT, LMA.

⭐ PCV provides a decelerating flow pattern, beneficial for patients with high airway resistance or poor compliance.

VCV mode waveforms: Volume, Flow, Paw, Pmus

Alarms & Safety - Code Red Rescuers

Error generating content for this concept group: Failed to process successful response

Monitoring & Waveforms - Patient Pulse Pointers

ETCO2 (Capnography): Normal 35-45 mmHg.
- ↓ETCO2: Hyperventilation, ↓perfusion, leak, esophageal intubation.
- ↑ETCO2: Hypoventilation, ↑CO2 production (MH), rebreathing.
- Waveform changes: Bronchospasm (shark-fin), spontaneous breaths (curare cleft).
SpO2: Target >94%.
Airway Pressures:
- $P_{peak}$ (max), $P_{plat}$ (alveolar pressure).
- ↑($P_{peak} - P_{plat}$): ↑Resistance (kinked ETT, bronchospasm).
- ↑$P_{plat}$: ↓Compliance (ARDS, pneumothorax).
Compliance: $Static = TV / (P_{plat} - PEEP)$ (Normal 50-70 mL/cmH2O).
Loops:
- P-V: Compliance, overdistension, leaks.
- F-V: Flow obstruction ("scooping").

⭐ Sudden ↓ETCO2 to near zero: Suspect esophageal intubation, circuit disconnect, or cardiac arrest.

High‑Yield Points - ⚡ Biggest Takeaways

Modern ventilators: Microprocessor-controlled; key modes include Volume Control Ventilation (VCV) (delivers set volume) & Pressure Control Ventilation (PCV) (delivers set pressure).

Circle system: Essential for CO2 absorption and efficient rebreathing of anesthetic gases.

Key monitoring parameters: Tidal Volume (VT), Respiratory Rate (RR), Peak Inspiratory Pressure (PIP), and Positive End-Expiratory Pressure (PEEP).

VCV ensures consistent minute ventilation; PCV limits airway pressures, reducing barotrauma risk.

Synchronized Intermittent Mandatory Ventilation (SIMV) allows spontaneous breaths between mandatory ones, aiding weaning.

Major complications: Include barotrauma, volutrauma, atelectasis, and Ventilator-Associated Pneumonia (VAP).

Fresh Gas Flow (FGF) decoupling: Critical in modern ventilators to prevent FGF changes from altering delivered tidal volume during VCV modes.

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Anesthesia Ventilators