This short cheat book talks about basic concepts and physiology of artificial ventilation and also elaborates on point guided approach in maneuvering different modes of mechanical ventilation. Consider this as a basic overview and is intended for all internal medicine residents.
Cardio pulmonary interactions during Mechanical Ventilation Dr.Mahmoud Abbas
Cardio pulmonary interactions during Mechanical Ventilation lecture presented by Dr Lluis blanch at the Egyptian Critical care Summit, the leading medical event in Egypt
A brief introduction to mechanical ventilation. contains details on the various variables, modes and settings on the mechanical ventilator. a simple explanation of what seems to be so complicated.
Patient ventilator interactions during mechanical ventilationDr.Mahmoud Abbas
Patient Ventilator Interaction during Mechanical Ventilation lecture presented by Dr.Lluis Blanch at Pulmonary Critical Care Egypt Meeting and Exhibition, January 2014. www.pccmegypt.com
Cardio pulmonary interactions during Mechanical Ventilation Dr.Mahmoud Abbas
Cardio pulmonary interactions during Mechanical Ventilation lecture presented by Dr Lluis blanch at the Egyptian Critical care Summit, the leading medical event in Egypt
A brief introduction to mechanical ventilation. contains details on the various variables, modes and settings on the mechanical ventilator. a simple explanation of what seems to be so complicated.
Patient ventilator interactions during mechanical ventilationDr.Mahmoud Abbas
Patient Ventilator Interaction during Mechanical Ventilation lecture presented by Dr.Lluis Blanch at Pulmonary Critical Care Egypt Meeting and Exhibition, January 2014. www.pccmegypt.com
These slides represent how to manage patients on a mechanical ventilator? Easy understanding of using ventilators. indication of mechanical ventilator use. How to wean a patient from a mechanical ventilator? How to fine-tune the ventilator settings?
Final newer modes and facts niv chandanChandan Sheet
THIS IS THE BASIC POINTS REGARDING NIV, THIS IS COMPILED AND ARRANGED FROM DIFFERENT BOOKS, JOURNALS AND PPTs.
The author is grateful to the teachers and authors of pulmonology and critical care.
Mechanical Ventilation (MV) is almost always a challenging topic for ICU nurses and practitioners. In this presentation we are going to review and relearn basics of MV together.
Salient features of the book are -
- The book provides a shortcut to understand and remember certain specific formulae and points you require to interpret the 12-lead ECG.
- Treatment protocols (in green boxes) for most of the important conditions are also included.
- View sample ECGs as you read along the topics.
- The content is explained in a very simple language to provide good conceptions, written from a student’s point of view.
- People can gain their belief in the book after going through sample ECGs which would be available at www.themedicalpost.net/ecg
- The book competes with the other books available in the market in simplicity, summaries, treatment protocols, live diagrams and regularly updated sample ECGs on the website.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
2. Mechanical Ventilation Cheat Book for IM-Residents 1
Content
I. The very basics
a. Ventilation and Oxygenation
b. Basic Parameters
c. Negative and Positive pressure ventilation
d. Impact of positive pressure ventilation in cardiac output
e. What is minute ventilation
II. Pressures and monitoring
a. Peak inspiratory pressures PIP
b. Plateau pressures
c. Common causes and complications of high airway pressures
d. Positive end-expiratory pressure PEEP
e. AutoPEEP, intrinsic PEEP or inadvertent PEEP
f. Flow time waveforms
III. Non invasive mechanical ventilation – BiPAP
a. Common parameters and settings
b. Clinical indications and contraindications
IV. Modes of invasive ventilation
V. Airway vs Alveolar disease
a. Ventilation strategy in COPD patients
b. Ventilation strategy in ARDS patients
VI. Ventilation in patients with severe metabolic acidosis
VII. Ventilation in patients with neuromuscular disease
VIII. Screening for weaning
a. Parameters
b. Weaning predictors
c. Upper airway swelling
IX. Spontaneous breathing trials
X. Common clinical scenarios
a. Patient with asthma exacerbation
b. Adjusting vent settings – 1
c. Adjusting vent settings – 2
d. Troubleshooting in COPD patients - diagnosis
e. Troubleshooting in COPD patients - management
3. Mechanical Ventilation Cheat Book for IM-Residents 2
The very basics
Mechanical ventilation has two major
components to it, Ventilation and Oxygenation.
Ventilation
It is the ability to remove CO2.
Mostly controlled by Tidal Volume and
Respiratory rate.
Oxygenation
Ability to allow alveolar oxygen gas exchange
with the blood.
Mostly controlled by oxygen concentration
(FiO2) and PEEP.
Parameters with common initial
values
1. Tidal Volume – 6-8 m/kg
Always use ideal body weight based on gender
and height. Not actual weight.
Think about it, what would be the tidal
volume for a patient weighing 400 lbs?
2. Respiratory Rate
Commonly set at 10 – 20 breaths/min.
Would often change based on indication for
mechanical ventilation.
3. PEEP
Set usually between 0-5 cm H20.
4. Fraction of inspired Oxygen
Common practice is to set it at 100 % and then
titrate accordingly.
5. Flow Rate
By default set at 40-60 Liters/min but would
change based on underlying treating pathology.
4. Mechanical Ventilation Cheat Book for IM-Residents 3
How do we normally breath?
We use our diaphragm to create a low pressure within their lungs (negative pressure
breathing). A pressure gradient is created (where the lungs are at a lower pressure) and air
flows into the lungs.
Positive pressure ventilation
When we put a patient on mechanical ventilation either invasive or non-invasive we change
their way of breathing and make them breath with a positive pressure ventilation.
Positive pressure ventilation essentially affects preload, afterload and ventricular compliance.
The net effect in most situations is a decrease in cardiac output.
Here is a brief summary of what happens when you put someone on a ventilator –
1. With negative pressure ventilation, Right atrial pressure in a normal individual is around
0-5 cm of water.
2. On adding PEEP, you add positive pressure in the intra thoracic cavity which is
transmitted to the Right atrium.
3. As a result of that the venous flow/ preload reduced there by decreasing the cardiac
output and the blood pressure. Hence unless contraindicated, be ready to give your
patient IV fluids when you put them on positive pressure ventilation.
5. Mechanical Ventilation Cheat Book for IM-Residents 4
What is minute ventilation?
MV = Tidal volume in Liters x Respiratory rate
How do you assess if you patient is ventilating
appropriately? PaCO2
35-45 mmHg Acceptable
range
Maintain settings
<35 mmHg Hyperventilating Decrease minute
ventilation (Vt or RR)
>45 mmHg Hypoventilating Increase minute
ventilation (Vt or RR)
6. Mechanical Ventilation Cheat Book for IM-Residents 5
Pressures and monitoring
Pressures depicted on the ventilator are produced by
resistance in the airway and or compliance of the
lungs.
PIP – Peak Inspiratory Pressure - Resistance
PIP is the highest level of pressure applied
to the lungs during inhalation.
Resistance anywhere along the path from the
ventilator to the lungs can cause an increase in PIP.
PIP should be kept below 35 cmH2O.
Plateau Pressure/Alveolar pressure - Compliance
Plateau pressure is the pressure in the lungs during
peak inspiratory hold.
Plateau pressure should be kept below 30 cmH2O.
Peak pressures in the lungs increases if the resistance
in the airways increases or if lungs become stiff.
Whereas the plateau pressures are only affected by
the lung compliance.
Examples of Elevated Peak
Pressures (Airway issues)
- Bronchospasm
- Retained secretions
- Mucous plug
- Blocked / kinked ETT
Examples of Elevated Plateau
Pressures (Lung compliance issues)
- Pulmonary edema
- Pneumothorax
- ARDS
- Consolidation
- Collapse
Complications of higher pressures
Airway pressure itself is not
particularly deleterious unless it
reflects excessive alveolar pressure.
Excessive alveolar pressure can have
a number of adverse effects:
- barotrauma may result in acute
lung injury (leading to ARDS) or
air leaks (e.g. pneumothorax,
pneumomediastinum).
- Excessive intrathoracic pressure
may also result, with potential
hemodynamic consequences
Pearl: So if the pressure alarm is
going off you need to know whether
it is a high peak pressure causing the
problem or a high plateau pressure.
7. Mechanical Ventilation Cheat Book for IM-Residents 6
PEEP
Positive end-expiratory pressure (PEEP) is the positive pressure that will remain in the airways
at the end of the respiratory cycle (end of exhalation).
To understand better divide PEEP in two categories,
Extrinsic PEEP is the pressure you set on the ventilator and is usually set at 5 cm of water.
Intrinsic PEEP, also called inadvertent PEEP or auto PEEP
It is iatrogenic. Occurs when the expiratory time is shorter than the time needed to fully deflate
the lungs, preventing the lung and chest wall from reaching an elastic equilibrium point.
Also called Air trapping.
How do you measure auto PEEP?
Expiratory hold maneuver
Depressing the expiratory hold or expiratory pause
button on the ventilator keeps the lungs at maximal
exhalation for about 1 second and allows you to
measure the total PEEP.
Next step
You can then calculate the intrinsic PEEP:
Total PEEP - set PEEP = intrinsic PEEP
Intrinsic PEEP > 0 air trapping
Identifying air trapping on a Flow time waveform
As long as the expiratory limb reaches zero,
the lung is fully deflated and the patient is not
air trapping.
A shift in the waveform, such that the
expiratory limb does not return to zero,
indicates air trapping.
8. Mechanical Ventilation Cheat Book for IM-Residents 7
Measures to treat air trapping in patients with COPD
1. Decrease VT
Reducing volume, in reduces volume needed to get out.
2. Decrease RR
Reducing RR allows more time to exhale.
3. Increase flow
Increasing flow shortens inspiration time and therefore increases expiration time.
4. Bronchodilators
5. Steroids
What to Do?
You are the MICU Intern, your nurse calls you to check a patient for alarming ventilator
pressures!
1. Check the circuit – look for any
disconnections!
2. Check the HME – the connector
between the ventilator and ET tube
3. Is the patient sedated enough? Watch
for patient ventilator dysynchrony.
4. Consider continuous bronchodilators
if the patient is wheezing.
In the meanwhile,
• Get a chest Xray
• Call for help! (Never be afraid of
asking for help) – reach out to the
Intensivist/ RT
Low Volume Alarm – watch for
• a disconnected circuit
• dislodged ET tube, cuff leak
• measure cuff pressure
• low set tidal voluime
9. Mechanical Ventilation Cheat Book for IM-Residents
8
8
Non Invasive Mechanical Ventilation – BIPAP
Parameters and Common Settings
1. Inspiratory positive airway pressure IPAP
Usually set between 10-20 mmHg
2. Expiratory positive airway pressure EPAP
Usually set between 5-10 mmHg
Analogous to PEEP
3. FiO2
Usually started at 100 % and then titrated
accordingly
Difference of pressures IPAP – EPAP
It is the difference between these two
pressures that drives the tidal volume.
Let’s see some sample settings and understand
how they differ,
a. IPAP/EPAP of 10/5, Delta is 5
b. IPAP/EPAP of 15/5, Delta is 10
c. IAPA/EPAP of 15/10, Delta is 5
Patient with settings b would produce
maximum tidal volume.
Patient with settings c would generate
maximum PEEP.
What is a strategy for the treatment of systolic
CHF?
Answer: BiPAP with high EPAP
Remember EPAP works like PEEP, it increases
the intrathoracic pressure and reduce
afterload, preload, and pushes out the fluid in
the lungs.
Which of the following will reduce the pCO2
and increase ventilation?
Answer: Increase IPAP and keep EPAP the same.
Common indications
§ Respiratory failure not requiring immediate
intubation with:
acute respiratory acidosis
unacceptable hypoxemia despite
supplemental oxygen
§ Intubation contraindicated or refused
§ Post extubation respiratory difficulty in
which re-intubation may be avoided with a
trial of BiPAP
Must requirements for BiPAP
§ Patient should be awake, alert and
cooperative
§ Patent upper airway and with intact reflexes
§ Ideally not much respiratory secretions
Common contraindications
§ Markedly depressed mental status
§ Excessive amount of secretions
§ Upper GI bleeding
§ Proper mask fit cannot be achieved
10. Mechanical Ventilation Cheat Book for IM-Residents 9
Different Modes of Mechanical Ventilation
Which initial mode of ventilation should I use?
Assist Control is the most widely used mode of mechanical ventilation by most providers.
VOLUME MODES
Assist Control
- Also known as continuous
mandatory ventilation (CMV).
- Patient gets the set tidal volume
with each breath (even with
partial breaths triggered by the
patient).
- More tendency to
hyperventilate.
SIMV
- Guarantees a certain number of
breaths, but unlike ACV, patient
breaths are partially their own.
- More tendency to hypoventilate.
ACV vs. SIMV
Personal preference prevails, except in the following scenarios: 1. Patients who breathe rapidly
on ACV should switch to SIMV 2. Patients who have respiratory muscle weakness and/or left-
ventricular dysfunction should be switched to ACV.
PRESSURE Assist Control
In this mode, you set the pressure and the ventilator would generate a tidal volume based on
lung compliance.
Majority of the time is spent at the higher (inspiratory) pressure.
Higher risks of auto PEEP and hemodynamic deterioration due to the decreased expiratory time
and increased mean airway pressure generally outweight the small potential for improved
oxygenation.
11. Mechanical Ventilation Cheat Book for IM-Residents 10
PRESSURE Support Mode
It is used to augment spontaneous breathing.
Can be used to overcome the resistance of ventilator tubing in another cycle (5 – 10 cm H20 are
generally used, especially during weaning).
12. Mechanical Ventilation Cheat Book for IM-Residents 11
Airway disease versus Alveolar disease
Airway Disease
A problem with ventilation
Obstructive disease
Signs:
Increased paCO2
Enlarged lungs on chest xray
Alveolar Disease
A problem with oxygenation
Restrictive disease
Signs:
Decreased PaO2
Lung size appears smaller on chest xray
Ventilation strategies in COPD Exacerbations
Often you will encounter elevated peak inspiratory pressures in a patient with COPD, as you
know they tend to have air trapping. You may apply following maneuvers to treat/prevent this;
a. Setting a low respiratory rate, allowing more time for expiration phase of breathing. But
remember you have to do it within reason or else you will hypoventilate the patient.
b. Increasing Inspiratory Flow Rate (IFR) to decrease Tinspiration and increase Texpiration. This
helps to avoid breath stacking.
Typically set at 80-100 for patients with COPD.
c. Providing an optimal PEEP: The external PEEP should be set at 70 % of the auto PEEP to help
with ventilation synchrony.
Pearl 1: Always ventilate to a target Ph of 7.35-7.40
Do not try reaching to a normal paCO2. Chronic COPD patient would have baseline elevations.
Pearl 2: Distinguishing between acute and chronic respiratory failure
13. Mechanical Ventilation Cheat Book for IM-Residents 12
Ventilation strategies in ARDS
In ARDS the affected part of the lungs is not
the airways, rather the pathology is at the
alveolar level.
Fluids fill the air sacs which often leads to
collapse and affects the gas exchange. This
causes refractory hypoxemia which does not
respond to high levels of FiO2.
Severity of ARDS = Oxygenation status
Below is the severity classification
How does your ventilation settings differ if you suspect ARDS?
1. Low tidal volume strategy
Increasing volume in does not help because the extra volume just
enters the normal alveoli and overextends them, further increasing
the plateau pressure above the acceptable 30 cm of water which can
often cause lung damage.
6-8 ml/kg à 4-6 ml/kg
14. Mechanical Ventilation Cheat Book for IM-Residents 13
2. High respiratory rate strategy
Increasing the respiratory rate would decrease paCO2 and cause Air
trapping. Air trapping is usually bad but it might help your ARDS
patient!!
It acts like PEEP and help recruit and stabilize the collapsed alveoli.
3. Optimal PEEP strategy
In this strategy, you adjust PEEP up and down
to find the PEEP at which the lung is the most
compliant. To determine when the lung is
most compliant you can monitor PaO2 or
calculate the static compliance.
PEEP that produces the highest PaO2 =
Optimal PEEP
PEEP that produces the highest static
compliance = Optimal PEEP
4. Using a different mode of ventilation
When treating patients with ARDS it is
common to switch from AC volume control
to a mode that is more lung protective.
When using AC volume control you need to
constantly adjust and readjust tidal volume
and PEEP to keep the lungs in the sweet
spot.
APRV Airway Pressure Release Ventilation Mode
It is a pressure controlled, intermittent mandatory ventilation with unrestricted spontaneous
breathing.
First described by Stock et al 1987. This mode of ventilation is often used as a rescue therapy
for severe ARDS.
Respiratory rate is not entered.
15. Mechanical Ventilation Cheat Book for IM-Residents 14
Description
- Two levels of PEEP: high (P-high) and low (P-low)
- Patient breaths spontaneously during P-high and P-low
- Time in P-high (T-high) is longer than P-low (T-low) to
maintain recruitment (85-95%)
- Results in a degree of autoPEEP due to the short release
time (T-low)
16. Mechanical Ventilation Cheat Book for IM-Residents 15
Use of prone positioning
In supine patients, the dorsal regions of the lung are susceptible to profound lung derecruitment
due to increases in parenchymal edema. Recognition that the heterogeneous atelectasis and
consolidation seen in ARDS is often dorsally distributed led investigators to question whether
care for patients with ARDS in the prone – as opposed to the supine – position may lead to
improved mortality outcomes.
An alveolus will remain open
when the intra-alveolar
pressure exceeds PPL. When a
patient with ARDS is placed
prone, the dorsal lung is no
longer subjected to high PPL
and dorsal lung atelectasis
decreases. Conversely, the
ventral lung units are exposed
to a higher PPL and are more
likely to collapse.
Absolute Contraindication
Shock
Acute bleeding
Multiple fractures or trauma (eg, unstable
fractures of femur, pelvis, face)
Spinal instability
Pregnancy
Raised intracranial pressure
Tracheal surgery or sternotomy within two
weeks
Selection Criteria
Patients with severe ARDS who fail to
improve despite use of above mentioned
ventilatory strategies, it is recommended to
try a trial of prone ventilation, provided
there is no contraindication.
Severe ARDS – PROSEVA trial defined
severe ARDS as those having a partial
pressure of arterial oxygen: fraction of
inspired oxygen (PaO2:FiO2) ratio <150
mmHg with a FiO2 ≥0.6 and PEEP ≥5 cm
H2O
17. Mechanical Ventilation Cheat Book for IM-Residents 16
Ventilation strategy in patients with severe
metabolic acidosis
Let’s understand this by using a common scenario,
You have a patient with severe DKA, ABG on admission is 7.21/21/70/8.
You were asked to see the patient for worsening dyspnea and was breathing at a rate of 30
breaths per min. Decision was made to intubate the patient and was started on positive
pressure ventilation.
Following initial parameters were set on the ventilator;
Mode AC-Volume, RR: 12, Tidal volume: 450, PEEP: 5 cm of water and FiO2 of 100 %
What do you think would happen to this patient?
Answer: It would not be surprising if the patient’s academia got worse soon after starting
mechanical ventilation.
Explanation: As mentioned in the clinical vignette, patient was noted to breath at 30 breaths
per min in the setting of severe academia. But as you sedate the patient and start mechanical
ventilation at 12 breaths a minute, you also happen to take away the patient’s capability to
compensative!
Pearl: Always watch and try to match for patient’s minute ventilation before you start
mechanical ventilation. Simulate patient’s existing ventilation requirements to keep up with
their demands.
Ventilation strategy in patients with
Neuromuscular weakness
Patient presents with progressive bilateral leg weakness and has high suspicion of Gulian barre
syndrome. How do you decide patient’s need for mechanical ventilation?
Calculate Negative inspiratory force (NIF) or Maximum inspiratory pressure (MIP)
It should be more negative than -20 cm of water. Remember a lower pressure (more negative)
is better!
Eg, if patient’s NIF is measured at -16 cm of water à Intubate the patient or do not extubate if
already on mechanical ventilation.
18. Mechanical Ventilation Cheat Book for IM-Residents 17
Screening for Weaning
Before weaning you need to screen your patient to make sure they meet the following criteria.
1. Cause of respiratory failure 2. Oxygenation status
Probably the most important.
The cause of respiratory failure should
have resolved or improved
SpO2 > 90% on FiO2 < 40%
PEEP < 5cm of water
3. Ventilation status 4. Hemodynamic status
Patient comfortable on the current vent
setting
Often breathing less than 35 breaths/min
Ph > 7.25
Low or no vasopressor requirements
5. Sedation status
No ongoing neuromuscular blocking
agents
Minimal or no sedation
Often patients would follow simple
commands
Weaning Predictors
Numerous weaning predictors have been studied, but none appear to be superior to objective
clinical criteria in predicting a patient's readiness to wean. The rapid shallow breathing index
(RSBI) is the most extensively studied and popular weaning predictor. It is discussed in detail
separately.
RSBI = RR/Tidal Volume in liters
RSBI ideally should be less than 105. RSBI < 80 predicts successful weaning in more than 95%
cases!
Upper Airway Swelling
When should you be concerned for upper airway swelling?
Answer: Cases of prolonged ventilation, traumatic
intubation and patients with smoke injuries.
How do we know when the swelling has decreased enough
in order to extubate the patient?
Answer: Deflate the cuff à Listen for air leak!
19. Mechanical Ventilation Cheat Book for IM-Residents 18
Spontaneous Breathing Trials
SBT refers to a patient breathing through the endotracheal tube either without any ventilator
support (eg, through a T-piece) or with minimal ventilator support.
Two widely used methods are;
CPAP and T-piece
CPAP T-piece
1. Switch patient from AC à CPAP mode
2. CPAP of 5 cm of water helps to distend
alveoli
3. Add pressure support of 6-8 cm of water
to help overcome equipment resistance
1. Switch patient from AC à T-piece
2. Remove all pressure support (but leave
connected to ventilator).
3. Keeping patient connected to ventilator
allows you to monitor spontaneous
breaths and VT.
If patient does well and appears comfortable for up-til 2 hours of the spontaneous breathing
trial à Proceed towards extubation
20. Mechanical Ventilation Cheat Book for IM-Residents 17
Screening for Weaning
Before weaning you need to screen your patient to make sure they meet the following criteria.
1. Cause of respiratory failure 2. Oxygenation status
Probably the most important.
The cause of respiratory failure should
have resolved or improved
SpO2 > 90% on FiO2 < 40%
PEEP < 5cm of water
3. Ventilation status 4. Hemodynamic status
Patient comfortable on the current vent
setting
Often breathing less than 35 breaths/min
Ph > 7.25
Low or no vasopressor requirements
5. Sedation status
No ongoing neuromuscular blocking
agents
Minimal or no sedation
Often patients would follow simple
commands
Weaning Predictors
Numerous weaning predictors have been studied, but none appear to be superior to objective
clinical criteria in predicting a patient's readiness to wean. The rapid shallow breathing index
(RSBI) is the most extensively studied and popular weaning predictor. It is discussed in detail
separately.
RSBI = RR/Tidal Volume in liters
RSBI ideally should be less than 105. RSBI < 80 predicts successful weaning in more than 95%
cases!
Upper Airway Swelling
When should you be concerned for upper airway swelling?
Answer: Cases of prolonged ventilation, traumatic
intubation and patients with smoke injuries.
How do we know when the swelling has decreased enough
in order to extubate the patient?
Answer: Deflate the cuff à Listen for air leak!
21. Mechanical Ventilation Cheat Book for IM-Residents 18
Spontaneous Breathing Trials
SBT refers to a patient breathing through the endotracheal tube either without any ventilator
support (eg, through a T-piece) or with minimal ventilator support.
Two widely used methods are;
CPAP and T-piece
CPAP T-piece
1. Switch patient from AC à CPAP mode
2. CPAP of 5 cm of water helps to distend
alveoli
3. Add pressure support of 6-8 cm of water
to help overcome equipment resistance
1. Switch patient from AC à T-piece
2. Remove all pressure support (but leave
connected to ventilator).
3. Keeping patient connected to ventilator
allows you to monitor spontaneous
breaths and VT.
If patient does well and appears comfortable for up-til 2 hours of the spontaneous breathing
trial à Proceed towards extubation
22. Mechanical Ventilation Cheat Book for IM-Residents 19
Common Clinical Scenarios
Question 1
A 23-year-old woman with a long history of asthma and previous exacerbations requiring
intubation is evaluated in the emergency department for a 2-day history of increasing wheezing
and dyspnea after the onset of a sore throat. She has used her albuterol inhaler many times in
the past day.
On physical examination, she is alert and cooperative but in severe respiratory distress; the
blood pressure is 160/80 mm Hg, heart rate is 120/min, and respiration rate is 30/min. She is
using accessory muscles of breathing. She has nasal flaring, and chest examination reveals
diffuse inspiratory and expiratory wheezes.
Peak expiratory flow rate is 110 L/min. Measurement of arterial blood gases shows a pH of
7.32, PCO2 of 44 mm Hg, and PO2 of 76 mm Hg with the patient breathing oxygen, 5 L/min by
nasal cannula. Chest radiograph shows hyperinflation but is otherwise normal.
Intravenous corticosteroid therapy is begun.
Which of the following is the most appropriate next step in this patient's management?
A An anticholinergic agent and a short-acting β-agonist
B Helium combined with oxygen (Heliox)
C Intravenous or inhaled magnesium sulfate
D Prompt intubation
Question 2
As you monitor the patient, you
obtain an ABG and check their
oxygen saturation and pressures on
the ventilator. You note these
values. What should you do next?
A. Decrease the PEEP
B. Increase the Tidal Volume
C. Decrease the Flow
D. Increase the FiO2
23. Mechanical Ventilation Cheat Book for IM-Residents 20
Question 3
Several hours after you increase
the FiO2, you note the values
shown. Based on your findings,
what should you do next?
A. Decrease the PEEP
B. Increase the Tidal Volume
C. Decrease the Flow
D. Increase the FiO2
Question 4
As you look at the ventilator
screen of your COPD patient, you
see this flow-time waveform. The
patient most likely has which of
the following?
A. Lung cancer
B. Pneumonia
C. Air trapping
D. Alveolar collapse
Question 5
As following the patient in Question 4, Which of the following should you NOT consider when
trying to reduce air trapping?
A. Decreasing the respiratory rate
B. Increasing the flow
C. Decreasing the inspiratory time
D. Increasing the tidal volume
Question 6
You suspect that your mechanically ventilated patient may have
developed ARDS. The PIP is 55 cmH2O and the plateau pressure
is 36 cmH2O. They are currently on AC volume control mode
with the following settings: tidal volume (VT) is 400 mL,
respiratory rate is 20 breaths/min, FiO2 is 60%, and PEEP is 5
cmH2O. The SpO2 on these settings is 94%.
Based on this information, what should you do?
A. Switch to SIMV
mode
B. Increase tidal
volume to 550 ml
C. Increase the FiO2
to 70 %
D. Switch to pressure
control mode