MS RLE 6F PART 1: Mechanical Ventilation, Pacemaking and ECG Interpretation

Mechanical Ventilation

a procedure where a machine (mechanical ventilator) takes over the work of breathing when a person is not able to breathe enough on their own.

Positive Pressure

type of ventilation in which air is pushed into the lungs at a pressure higher than atmospheric pressure.

Negative Pressure

type of ventilation in which air is pulled into the lungs by creating a lower pressure inside the chest cavity than atmospheric pressure

Mandatory Breath

is a ventilator-delivered breath that occurs regardless of the patient's effort to initiate a breath.

Spontaneous Breath

a breath that is done and is controlled by the patient.

Pacemaker

is a medical device that is implanted to regulate the heartbeat by sending electrical impulses to stimulate the heart muscle to contract.

Pacemaker Lead

a thin, flexible wire that carries the electrical pulses from the pacemaker to the heart muscle

Carry the impulse created by the generator to the heart.

Capture

refers to the successful initiation of a heartbeat by the pacemaker's electrical impulse.

Pacing Artifact

- is the visual representation of the pacemaker's electrical impulse on an electrocardiogram (ECG).

Distorted, irrelevant, and extraneous electrocardiographic (ECG)

waveforms.

Milliampere

unit of electrical current, equal to one-thousandth of an ampere.

A measure for small electric currents.

Sense

refers to the pacemaker's ability to detect the patient's own heartbeats/pulse

Sensitivity

the minimum electrical signal that a pacemaker needs to detect the heart. How well the pacemaker can "listen" to the heart's electrical signals.

Threshold

determines the level of electrical activity the pacemaker must detect before it initiates a pacing impulse. The "trigger point".

Electrocardiography

The process of producing an electrocardiogram.

Is a simple test that can be used to check your heart's rhythm and

electrical activity.

Electrocardiograph/ electrocardiogram

machine/instrument used to record the heart's electrical activity,

Electrophysiology

a test that assesses a heart's electrical system and used to diagnose

Electrodes

Medical sensors used to detect and transmit electrical signals from the body to medical devices, such as in electrocardiography or pacemaker systems.

Lead

A conductor, often a wire, that connects an implantable medical device (such as a pacemaker or defibrillator) to a specific site within the body

Fourth intercostal space on the right sternum.

placement of v1

Fourth intercostal space at the left sternum.

placement of v2

Midway between placement of V2 and V4.

placement of v3

Fifth intercostal space at the midclavicular line.

placement of v4

Anterior axillary line on the same horizontal

level as V4.

placement of v5

Mid-axillary line on the same horizontal level as

V4 and V5.

placement of v6

Anywhere between the right shoulder and right

elbow.

placement of RA (Right Arm)

Anywhere below the right torso and above the

right ankle.

placement of RL (Right Leg)

Anywhere between the left shoulder and the

left elbow.

placement of LA (Left Arm)

Anywhere below the left torso and above the

left ankle.

placement of LL (Left Leg)

Automaticity

The inherent ability of the cardiac cells to generate spontaneous electrical impulses.

Excitability

The property of cells to respond to electrical stimulation by generating an action potential or a change in electrical potential.

-Acute Respiratory Syndrome (ARDS)

-Cardiac Arrest

-Coma

give indications for mechanical ventialtion

-Tension Pneumothorax

-Hypovolemic shock

- high ICP

give contraindications for mechanical ventialtion

-permanent slow or temporary slower-than-normal impulse formation

-Asymptomatic Atrioventricular Block

give indications for Pace Making

-Severe bleeding

-Active systemic infection

give contraindications for Pace Making

-Irregular heartbeat or palpitations

-Pre-surgery check

give indications for ECG analysis

-Avoid if chest skin issues

-patient refuses

give contraindications for ECG analysis

-oxygen level is good (PaO2 >60 mmHg)

-stable heart and blood pressure

-breathing muscles are strong

-patient awake

when will you discontinue mechanical ventilation

○ T-piece trial (breathes through tube without ventilator support)

○ CPAP (continuous positive airway pressure)

○ Low pressure support (ventilator gives a little help with each breath)

methods to perform spontaneous breathing trial

Volume-cycled ventilators

Types of Positive-Pressure Ventilation

Deliver a consistent, preset volume of air with each breath, ensuring stable and adequate ventilation regardless of changes in airway pressure. A

Pressure-cycled ventilators

Types of Positive-Pressure Ventilation

Delivers air until a preset pressure is reached, then cycles off, allowing for exhalation.

High-frequency Oscillatory Support Ventilators (HFOV)

Types of Positive-Pressure Ventilation

Deliver extremely rapid breaths (180 to 900 breaths per minute) with very low tidal volumes and high airway pressures.

Non-invasive Positive-Pressure Ventilation (NIPPV)

Types of Positive-Pressure Ventilation

Delivers breathing support via masks or nasal devices without the need for intubation, reducing infection risk.

Iron Lungs

Types of Negative-Pressure Ventilators

This large, cylindrical device encloses a patient's body (except the head) and creates negative pressure around the chest, which helps airflow into the lungs

Chest Cuirass

Types of Negative-Pressure Ventilators

A smaller, wearable negative-pressure ventilator that fits over the chest and abdomen, creating suction to facilitate breathing. It's sometimes called a "chest shell" and is less restrictive than the iron lung.

Exovent

Types of Negative-Pressure Ventilators

- A modern, more portable negative-pressure ventilator prototype inspired by the iron lung. I

Continuous Mandatory Ventilation (CMV)

VENTILATION SETTINGS/MODE

Also known as Assist-Control Ventilation (ACV)

The ventilator delivers a fixed number of breaths at a set volume or pressure.

The machine completely controls breathing, even if the patient tries to initiate a breath.

Intermittent Mandatory Ventilation (IMV)

VENTILATION SETTINGS/MODE

The ventilator provides a set number of breaths, but the patient can breathe on their own between them.

The patient's spontaneous breaths are not assisted by the ventilator.

Synchronized Intermittent Mandatory Ventilation (SIMV)

VENTILATION SETTINGS/MODE

Similar to IMV, but the ventilator synchronizes with the patient's breathing efforts.

It delivers mandatory breaths only when the patient is not initiating a breath.

Pressure Support Ventilation (PSV)

VENTILATION SETTINGS/MODE

The patient initiates all breaths, and the ventilator provides a preset pressure to make inhaling easier.

This mode reduces the patient's breathing effort.

Airway Pressure Release Ventilation (APRV)

VENTILATION SETTINGS/MODE

This mode maintains continuous positive airway pressure but allows brief pressure releases for exhalation.

It helps improve oxygenation while allowing the patient to breathe spontaneously.

Proportional Assist Ventilation (PAV)

VENTILATION SETTINGS/MODE

The ventilator adjusts the pressure support in proportion to the patient's breathing effort.

The more effort the patient exerts, the more assistance the ventilator provides, allowing natural breathing.

-VAP

-atelectasis

-oxygen toxicity

give me 3 ventilator related problems

Transcutaneous pacemaker

Types of Temporary Pacemakers

Which type of pacemaker is used as an emergency, non-invasive method to manage bradycardia?

Transvenous pacemaker

Types of Temporary Pacemakers

In which pacemaker type is a pacing wire inserted through a vein and guided into the heart chambers?

Membrane Potential

It's the difference in electrical charge between the inside and outside of a heart cell.

This happens because of how ions like sodium (Na⁺), potassium (K⁺), and calcium (Ca²⁺) move in and out.

Depolarization

inside becomes more positive.

Hyperpolarization

inside becomes more negative.

Resting Membrane Potential

It's the steady electrical charge of a heart cell when it's not active (around -90 mV).

Maintained by the sodium-potassium pump (moves 3 Na⁺ out, 2 K⁺ in)

Action Potential

It's a quick change in the cell's charge that spreads across the heart, causing it to contract.

Sinoatrial (SA) Node

Electrical Conduction of the Heart

Natural pacemaker in the right atrium; starts the action potential and sets the heart rate.

•Atrioventricular (AV) Node

Electrical Conduction of the Heart

: Between atria and ventricles; slows the impulse so the atria contract before the ventricles

Bundle of His

Electrical Conduction of the Heart

Carries the impulse from the AV node to the ventricles.

Right & Left Bundle Branches

Electrical Conduction of the Heart

Transmit the impulse through the interventricular septum to each ventricle.

Purkinje Fibers

Electrical Conduction of the Heart

Spread the impulse across the ventricles, causing coordinated contraction.