Test #2 ventilation

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Questions and Answers

What does OPA stand for, and what are its indications?

OPA stands for Oropharyngeal Airway. Indications include relieving upper airway obstruction if maneuvers fail, facilitating bag-mask ventilation, and serving as a bite block in intubated patients.

An OPA is contraindicated if the patient has an active gag reflex.

True (A)

How is the correct size for an Oropharyngeal Airway (OPA) measured?

Measure the distance from the center of the patient's mouth to the angle of the jaw (ear lobe).

What does ETT stand for, and what are the common adult sizes for females and males?

ETT stands for Endotracheal Tube. Common adult sizes are 6.5-7.5mm for females (depth 20-22 cm at lips/teeth) and 7.5-8.5mm for males (depth 22-24 cm at lips/teeth). Signup and view all the answers

What does LMA stand for, and what is its primary function?

LMA stands for Laryngeal Mask Airway. Its primary function is to provide a seal at the opening of the trachea and esophagus, serving as an alternative to endotracheal intubation for ventilation. Signup and view all the answers

An LMA provides definitive protection against aspiration.

False (B) Signup and view all the answers

Nasopharyngeal Airways (NPAs) can be used in conscious patients.

True (A) Signup and view all the answers

What is the ideal cuff pressure range for an Endotracheal Tube (ETT), and what is the maximum recommended pressure?

The ideal cuff pressure is around 25 cmH2O. The maximum recommended pressure is 30 cmH2O to minimize the risk of tracheal injury. Signup and view all the answers

Where should the tip of an Endotracheal Tube (ETT) be positioned relative to the carina?

The tip of the ETT should ideally be positioned 2-5 cm above the carina. Signup and view all the answers

Describe the Minimal Occlusion Volume (MOV) technique for ETT cuff inflation.

Slowly inflate the cuff with air during positive pressure ventilation until the air leak heard around the cuff during end-inspiration stops. Signup and view all the answers

Describe the Minimal Leak Technique (MLT) for ETT cuff inflation.

Inflate the cuff until the leak stops (as in MOV), then slowly remove a small amount of air until a very slight leak is heard at peak inspiration. Signup and view all the answers

Match the intubation blade type with its description:

Miller = Straight blade that lifts the epiglottis directly Macintosh = Curved blade that lifts the epiglottis indirectly by placing the tip in the vallecula Signup and view all the answers

Which of the following are indications for initiating mechanical ventilation? (Select all that apply)

Acute Respiratory Failure (pH < 7.25) (B), Possible impending respiratory failure (C), Prophylactic support (e.g., certain neuro injuries, epiglottitis) (D) Signup and view all the answers

Which of the following are primary objectives of mechanical ventilation? (Select all that apply)

Decrease work of breathing (WOB) (A), Correct acid-base imbalances (D), Improve ventilation (E) Signup and view all the answers

How should you verify that an intubation laryngoscope blade is functioning correctly?

Attach the blade to the handle and check that the light source illuminates brightly. If not, check the batteries in the handle, tighten or replace the bulb (if applicable), or try a different blade and/or handle. Signup and view all the answers

According to the provided text, what pH level indicates respiratory failure potentially requiring mechanical ventilation?

pH < 7.25 Signup and view all the answers

List the typical initial ventilator settings mentioned for Tidal Volume (Vt), Respiratory Rate (f), FiO2, I:E ratio, and PEEP.

Vt: 6-8 ml/kg (based on IBW) F: 12-20 breaths/min FiO2: 100% (emergency) or 40% (starting point) or patient's prior setting I:E: Based on condition (e.g., 1:2, 1:4) PEEP: 5 cmH2O Signup and view all the answers

Initial tidal volume (Vt) settings on a ventilator should be based on the patient's _____.

Ideal Body Weight (IBW) Signup and view all the answers

While PEEP can be adjusted, a maximum of _____ cmH2O is mentioned due to the risk of barotrauma.

40 Signup and view all the answers

What are the target temperatures for humidification when a patient has an ETT/Trach versus when they are on Mask Ventilation?

ETT/Trach: 37°C (good standard) Mask Ventilation: 31-34°C (start at 34°C, reduce if too hot for the patient) Signup and view all the answers

Using a Heat and Moisture Exchanger (HME) can potentially cause issues with increased resistance and moisture buildup.

True (A) Signup and view all the answers

Define Trigger, Cycle, Sensitivity, and Limit in the context of a ventilator breath cycle.

Trigger: What initiates (starts) the breath. Cycle: What terminates (ends) the inspiratory phase. Sensitivity: How easily a patient effort can trigger a breath. Limit: A preset maximum (e.g., pressure, volume, flow) that cannot be exceeded during inspiration but does not end the inspiratory phase itself. Signup and view all the answers

In the absence of patient spontaneous breaths, what typically triggers a ventilator breath in controlled modes?

Time Signup and view all the answers

Define lung compliance in the context of mechanical ventilation.

Lung compliance refers to the distensibility of the lungs and chest wall; essentially, how easily the lungs expand when pressure is applied (change in volume per change in pressure). Signup and view all the answers

What is the difference between dynamic compliance and static compliance?

Dynamic compliance reflects compliance during airflow (movement of air), incorporating airway resistance. Static compliance reflects the compliance of the lungs and chest wall measured under conditions of no airflow (e.g., during an inspiratory hold). Signup and view all the answers

List four factors mentioned that can influence lung compliance.

<ol> <li>Lung 'stiffness' (e.g., fibrosis)</li> <li>Muscular tension</li> <li>Secretions and fluid in the lungs</li> <li>Alveolar surface tension</li> </ol> Signup and view all the answers

Define 'Pressure' as it relates to mechanical ventilation and list its common units.

Pressure is the force exerted by gases within the lungs and airways. Common units are centimeters of water (cmH2O) or millimeters of mercury (mmHg). Signup and view all the answers

Define 'Flow' as it relates to mechanical ventilation and list its common units.

Flow is the rate of movement of air into and out of the lungs. It is typically measured in liters per minute (L/min). Signup and view all the answers

Describe the relationship between pressure, flow, and resistance in the airways.

The flow of air is directly proportional to the pressure difference (gradient) between the atmosphere/ventilator and the alveoli, and inversely proportional to the resistance of the airways. Signup and view all the answers

What is the formula for calculating Minute Ventilation (Ve)?

$V_e = V_t \times f$ (where Vt is tidal volume and f is respiratory rate/frequency) Signup and view all the answers

What does MAP stand for in mechanical ventilation, and what are the typical ranges provided for Normal, Obstructive disease, and ARDS patients?

MAP stands for Mean Airway Pressure. It is the average pressure applied to the lungs throughout the entire respiratory cycle. Normal: 5-10 cmH2O Obstructive: 10-20 cmH2O ARDS: 15-30 cmH2O Signup and view all the answers

Define Barotrauma in the context of mechanical ventilation.

Barotrauma is lung injury caused by excessive pressure in the alveoli, leading to damage such as pneumothorax, pneumomediastinum, or subcutaneous emphysema. Signup and view all the answers

What does PEEP stand for, and what is its primary effect on oxygenation?

PEEP stands for Positive End Expiratory Pressure. It improves oxygenation by preventing alveolar collapse at the end of expiration, increasing functional residual capacity (FRC) and improving V/Q matching. Signup and view all the answers

How does increasing PEEP typically affect blood pressure (BP)?

Decreases BP (A) Signup and view all the answers

What is the normal starting PEEP setting, and when might PEEP increases be considered relative to FiO2?

Normal starting PEEP is typically 5 cmH2O. PEEP increases are often considered after the FiO2 reaches 60% if oxygenation goals are still not met. Signup and view all the answers

List two contraindications or situations where PEEP should be used cautiously.

<ol> <li>Hemodynamic instability (Low BP, cardiac compromise)</li> <li>Head trauma or increased Intracranial Pressure (ICP)</li> </ol> Signup and view all the answers

What formula relates Flow (L/min), Tidal Volume (Vt), and Inspiratory Time (I time)?

$\frac{\text{Flow (L/min)}}{60 \text{ sec}} = \frac{V_t \text{ (L)}}{I_{\text{time}} \text{ (sec)}}$ or simpler: Flow (L/sec) = Vt (L) / I Time (sec) Signup and view all the answers

What is the purpose of setting a Pressure Limit on a ventilator?

A pressure limit is a safety feature set to prevent excessive peak inspiratory pressure (Ppeak), thereby protecting the patient's lungs from barotrauma due to over-inflation. Signup and view all the answers

What is Total Cycle Time (TCT), and how is it calculated?

TCT is the total time for one complete respiratory cycle (inspiration + expiration). It is calculated by dividing 60 seconds by the set respiratory rate (RR or f). TCT = 60 / RR. Signup and view all the answers

Explain the I:E Ratio and provide the typical ratios mentioned for Normal, Restrictive, and Obstructive lung conditions.

The I:E Ratio represents the ratio of the duration of inspiration to the duration of expiration. It consists of parts, not seconds. Normal: 1:2 or 1:3 (1:3 most common) Restrictive (e.g., ARDS): 1:1 or 1:2 Obstructive (e.g., COPD): 1:4 (consider up to 1:6) Signup and view all the answers

What is PIP (Peak Inspiratory Pressure), and what does it reflect?

PIP is the maximum pressure reached in the airways during the inspiratory phase of mechanical ventilation. It reflects the pressure needed to overcome both airway resistance (RAW) and the elastic recoil of the lungs and chest wall (compliance). Signup and view all the answers

What does a high PIP (Peak Inspiratory Pressure), generally above 30 cmH2O, suggest?

A high PIP suggests increased resistance to airflow or decreased lung/chest wall compliance (stiffness). Signup and view all the answers

What is Pplat (Plateau Pressure), and what does it reflect?

Pplat is the pressure measured in the airways at the end of inspiration during a period of no airflow (an inspiratory pause/hold). It reflects the pressure required to distend the alveoli and overcome the elastic recoil of the respiratory system (lung and chest wall compliance), excluding airway resistance. Signup and view all the answers

What does a high Pplat (Plateau Pressure), typically targeted below 30 cmH2O, suggest?

A high Pplat suggests decreased lung or chest wall compliance (stiffer lungs/chest wall) or overdistension from excessive tidal volume. Signup and view all the answers

What is the formula for calculating Static Compliance (Cs)?

$C_s = \frac{V_t}{P_{plat} - PEEP}$ Signup and view all the answers

What is the formula for calculating Airway Resistance (RAW)?

$RAW = \frac{PIP - P_{plat}}{\text{Flow}}$ (Flow needs to be in L/sec) Signup and view all the answers

What conditions might cause a high PIP (Peak Inspiratory Pressure) with a relatively normal Pplat (Plateau Pressure)?

Conditions that increase airway resistance without significantly affecting lung compliance, such as bronchospasm, secretions in the airway, or kinking/biting of the endotracheal tube. Signup and view all the answers

What conditions might cause both high PIP (Peak Inspiratory Pressure) and high Pplat (Plateau Pressure)?

Conditions that decrease lung or chest wall compliance, such as ARDS, pneumonia, pulmonary edema, large pleural effusions, pneumothorax, or abdominal distension. Signup and view all the answers

Describe Synchronized Intermittent Mandatory Ventilation (SIMV) mode.

SIMV delivers a set number of mandatory breaths (volume or pressure controlled) at a set rate. However, it synchronizes the delivery of these mandatory breaths with the patient's own spontaneous efforts if they occur near the scheduled time. Patients can also breathe spontaneously between mandatory breaths, often with pressure support. Signup and view all the answers

Describe Pressure Control Ventilation (PCV) mode.

In PCV, the ventilator delivers breaths by applying a preset inspiratory pressure for a preset inspiratory time. The peak pressure is constant with each breath, but the tidal volume delivered can vary depending on the patient's lung compliance and airway resistance. Signup and view all the answers

Describe Volume Control Ventilation (VCV) mode.

In VCV (often part of Assist/Control or SIMV), the ventilator delivers a preset tidal volume with each mandatory breath. The volume delivered is constant, but the peak inspiratory pressure required to deliver that volume can vary depending on the patient's lung mechanics (resistance and compliance). Signup and view all the answers

Describe Pressure Support Ventilation (PSV) mode.

PSV is a spontaneous breathing mode where the patient triggers every breath and controls the respiratory rate and inspiratory time. The ventilator provides a preset level of positive pressure support during inspiration to augment the patient's effort and tidal volume, reducing the work of breathing. Signup and view all the answers

Describe Continuous Positive Airway Pressure (CPAP).

CPAP provides a constant level of positive pressure throughout the entire respiratory cycle (inspiration and expiration) for spontaneously breathing patients. It helps keep alveoli open, increases FRC, and improves oxygenation. Signup and view all the answers

Describe Bilevel Positive Airway Pressure (BiPAP).

BiPAP delivers two levels of positive pressure: a higher Inspiratory Positive Airway Pressure (IPAP) during inspiration and a lower Expiratory Positive Airway Pressure (EPAP) during expiration for spontaneously breathing patients. EPAP functions similarly to PEEP/CPAP, while the difference between IPAP and EPAP provides pressure support to augment ventilation. Signup and view all the answers

Describe Airway Pressure Release Ventilation (APRV).

APRV is a mode characterized by prolonged periods at a high continuous positive airway pressure level (P-high) for a set time (T-high), intermittently interrupted by brief releases to a lower pressure level (P-low) for a short time (T-low). Patients can breathe spontaneously at both pressure levels. Signup and view all the answers

Suggest typical initial ventilator settings strategy for a patient with COPD.

Mode: Often SIMV or A/C, may consider non-invasive BiPAP initially. Vt: 6-8 mL/kg IBW. f: Lower rate (e.g., 10-12 bpm) to allow long expiratory time. PEEP: Low (e.g., 5 cmH2O), monitor for auto-PEEP. FiO2: Titrate to SpO2 88-92% or PaO2 ~60 mmHg. I:E Ratio: Needs long expiratory time (e.g., 1:4 or longer) to prevent air trapping. Signup and view all the answers

List general criteria often considered before attempting to wean a patient from mechanical ventilation.

<ul> <li>Resolution or significant improvement of the underlying cause for ventilation.</li> <li>Hemodynamic stability (adequate BP, minimal vasopressors).</li> <li>Adequate oxygenation (e.g., PaO2/FiO2 > 150-200, PEEP ≤ 5-8 cmH2O, FiO2 ≤ 0.4-0.5).</li> <li>Adequate ventilation (pH ≥ 7.25).</li> <li>Patient awake, alert, and cooperative (or able to protect airway).</li> <li>Absence of significant respiratory secretions.</li> </ul> Signup and view all the answers

What does SBT stand for, what are typical ventilator settings during an SBT, and how long does it usually last?

SBT stands for Spontaneous Breathing Trial. Typical settings involve minimal support, such as CPAP of 5 cmH2O or Pressure Support of 5-7 cmH2O. An SBT usually lasts between 30 minutes and 2 hours. Signup and view all the answers

What does RSBI stand for, how is it calculated, and what value typically suggests readiness for extubation?

RSBI stands for Rapid Shallow Breathing Index. It is calculated by dividing the spontaneous respiratory rate (f) by the spontaneous tidal volume (Vt in Liters): RSBI = f / Vt. An RSBI value less than 105 breaths/min/L generally suggests readiness for extubation. Signup and view all the answers

What is the purpose of a cuff leak test, and how is it performed?

The purpose is to assess for upper airway edema or obstruction around the ETT before extubation. It is performed by deflating the ETT cuff and observing or listening for airflow around the tube during mandatory or spontaneous breaths. Signup and view all the answers

List common causes of a high-pressure alarm on a mechanical ventilator.

Common causes include: <ul> <li>Patient coughing or gagging</li> <li>Secretions obstructing the airway/ETT</li> <li>Kinked or bitten ETT</li> <li>Bronchospasm</li> <li>Water in the ventilator tubing</li> <li>Decreased lung compliance (e.g., ARDS, PNA, edema)</li> <li>Pneumothorax</li> <li>Patient-ventilator asynchrony</li> </ul> Signup and view all the answers

List common causes of a low-pressure or low-volume alarm on a mechanical ventilator.

Common causes include: <ul> <li>Disconnection from the ventilator circuit</li> <li>Leak in the ventilator circuit</li> <li>ETT cuff leak or deflation</li> <li>Extubation (accidental or self)</li> <li>Chest tube leak (if applicable)</li> </ul> Signup and view all the answers

What are the typical target ranges for PaO2 and SpO2 for most mechanically ventilated patients?

PaO2: Typically 55-80 mmHg (or sometimes higher, up to 100 mmHg) SpO2: Typically 88-95% Signup and view all the answers

What are 'scalars' in mechanical ventilation, and what are the three main types?

Scalars are graphical displays showing a single ventilator variable (parameter) plotted against time. The three main types are Pressure-time, Flow-time, and Volume-time scalars. Signup and view all the answers

What are 'loops' in mechanical ventilation, and what are the two main types?

Loops are graphical displays showing the relationship between two ventilator variables simultaneously throughout a breath cycle. The two main types are the Pressure-Volume (P-V) loop and the Flow-Volume (F-V) loop. Signup and view all the answers

What does an apnea alarm indicate on a ventilator, and what are potential causes?

An apnea alarm indicates that the patient has not initiated a breath (spontaneous or triggered) within a preset time interval. Potential causes include oversedation, neuromuscular blockade, central nervous system depression, or respiratory muscle fatigue. Signup and view all the answers

Summarize the basic rules for interpreting Arterial Blood Gases (ABGs) based on pH, PaCO2, and HCO3.

<ol> <li>Look at pH: < 7.35 = Acidosis, > 7.45 = Alkalosis.</li> <li>Look at PaCO2 (Respiratory component): Normal 35-45 mmHg. If opposite to pH change (e.g., pH low, PaCO2 high), it's the primary cause (respiratory acidosis/alkalosis).</li> <li>Look at HCO3 (Metabolic component): Normal 22-26 mEq/L. If same direction as pH change (e.g., pH low, HCO3 low), it's the primary cause (metabolic acidosis/alkalosis).</li> <li>Check for Compensation: See if the component not causing the primary problem is moving in the opposite direction to try and normalize pH.</li> </ol> Signup and view all the answers

Explain the difference between uncompensated, partially compensated, and fully compensated acid-base imbalances.

<ul> <li>Uncompensated: Abnormal pH, one component (PaCO2 or HCO3) is abnormal explaining the pH change, the other component is normal.</li> <li>Partially Compensated: Abnormal pH, both PaCO2 and HCO3 are abnormal, moving in directions that attempt to correct the pH, but pH remains outside the normal range (7.35-7.45).</li> <li>Fully Compensated: pH is within the normal range (7.35-7.45), but both PaCO2 and HCO3 are abnormal, indicating the body has successfully counteracted the primary imbalance.</li> </ul> Signup and view all the answers

What is the fundamental difference between scalars and loops on a ventilator display?

Scalars display a single variable (Pressure, Flow, or Volume) plotted against Time. Loops display the relationship between two variables simultaneously (Pressure vs. Volume, or Flow vs. Volume), independent of time for the overall shape. Signup and view all the answers

What is a contraindication for using an Oropharyngeal Airway (OPA)?

The presence of a gag reflex in the patient. Signup and view all the answers

How do you measure for the correct size of an Oropharyngeal Airway (OPA)?

Measure the distance from the center of the patient's mouth to the angle of the jaw (or earlobe). Signup and view all the answers

What are contraindications for using a Nasopharyngeal Airway (NPA)?

Nasal obstruction or sinus infection. Significant facial trauma or suspected basilar skull fracture are also relative contraindications. Signup and view all the answers

What are the typical adult sizes and recommended cuff pressure for an LMA?

Typical adult sizes are 4-5. The recommended cuff inflation pressure is approximately 50 cmH2O (or just enough to achieve a seal). Signup and view all the answers

What is a major limitation or contraindication of using an LMA?

It does not protect the airway from aspiration of gastric contents. Signup and view all the answers

What does ETT stand for?

Endotracheal Tube. Signup and view all the answers

What are the common adult sizes and insertion depths for Endotracheal Tubes (ETTs)?

Females: 6.5-7.5mm tube size; 20-22 cm depth at the teeth/lips. Males: 7.5-8.5mm tube size; 22-24 cm depth at the teeth/lips. Signup and view all the answers

What is the ideal and maximum recommended cuff pressure for an ETT?

The ideal cuff pressure is around 25 cmH2O. The maximum recommended pressure is 30 cmH2O. Signup and view all the answers

Where should the tip of the ETT be positioned in the airway?

The tip should be positioned 2-5 cm above the carina (the bifurcation of the trachea). Signup and view all the answers

Match the intubation blade type with its description and method of lifting the epiglottis:

Miller = Straight blade ('l' in Miller); lifts the epiglottis directly. Macintosh = Curved blade; lifts the epiglottis indirectly by placing the tip in the vallecula. Signup and view all the answers

What are the primary objectives of initiating mechanical ventilation?

<ol> <li>Improve ventilation (primarily CO2 removal) and subsequently oxygenation. 2. Decrease the work of breathing (WOB). 3. Improve acid-base imbalances (correct respiratory acidosis). 4. Assist in improving metabolic issues (compensate for metabolic acidosis/alkalosis).</li> </ol> Signup and view all the answers

List the main indications for initiating mechanical ventilation.

<ol> <li>Acute Respiratory Failure (defined by criteria like pH < 7.25, PaCO2 > 50 mmHg, PaO2 < 60 mmHg). 2. Impending Respiratory Failure (evidence of increasing WOB, fatigue, deteriorating gas exchange). 3. Prophylactic support (e.g., certain neurological diseases/injuries, airway protection in conditions like epiglottitis, post-operative recovery, facilitation of wound healing by ensuring adequate oxygenation).</li> </ol> Signup and view all the answers

What are typical initial settings for Tidal Volume (Vt), Respiratory Rate (f), FiO2, I:E Ratio, PEEP, and Mode on a mechanical ventilator?

Vt: 6-8 ml/kg (based on Ideal Body Weight - IBW). f: 12-20 breaths/min. FiO2: 100% in emergencies, otherwise 40% or match patient's prior O2 level. I:E Ratio: Based on condition (e.g., 1:2 common, 1:4 for COPD, 1:1.5-1:2 for ARDS). PEEP: Start at 5 cmH2O. Mode: Varies based on goals (e.g., Assist/Control, SIMV). Signup and view all the answers

Initial tidal volume (Vt) settings on a ventilator are typically - ml/kg based on .

6-8, Ideal Body Weight Signup and view all the answers

The maximum PEEP level is generally considered cmH2O due to the risk of .

40, barotrauma Signup and view all the answers

Why is humidification crucial for mechanically ventilated patients, and what are the target temperatures?

Humidification is essential because the natural warming and humidifying function of the upper airway is bypassed. Target temperatures are typically 37°C for invasively ventilated patients (ETT/Trach) and 31-34°C for non-invasive mask ventilation. Signup and view all the answers

In the absence of spontaneous patient effort, what typically triggers a ventilator breath in controlled modes?

Time. Signup and view all the answers

What is respiratory system compliance, and what do high and low compliance indicate?

Compliance refers to the ease with which the lungs and chest wall can be stretched or distended (change in volume per unit change in pressure). High compliance means the lungs inflate easily but may have poor elastic recoil (hard to get air out, e.g., emphysema). Low compliance means the lungs are stiff and difficult to inflate (e.g., ARDS, fibrosis). Signup and view all the answers

List factors that can influence respiratory system compliance.

<ol> <li>Lung stiffness (e.g., Fibrosis, ARDS, Pulmonary Edema). 2. Chest wall stiffness or muscular tension. 3. Presence of secretions or fluid in the lungs/airways. 4. Alveolar surface tension (surfactant levels).</li> </ol> Signup and view all the answers

Define pressure in the context of mechanical ventilation and state its common units.

Pressure is the force exerted by gases within the lungs and airways during ventilation. It is typically measured in centimeters of water (cm H2O). Signup and view all the answers

Define flow in the context of mechanical ventilation and state its common units.

Flow is the rate at which air moves into or out of the lungs. It is measured in liters per minute (L/min). Signup and view all the answers

What is Minute Ventilation (Ve) and how is it calculated?

Minute Ventilation (Ve) is the total volume of air breathed in or out per minute. It is calculated as Tidal Volume (Vt) multiplied by Respiratory Rate (f): Ve = Vt x f. Signup and view all the answers

What is Mean Airway Pressure (MAP), and what are typical ranges for normal lungs, obstructive disease, and ARDS?

Mean Airway Pressure (MAP) is the average pressure applied to the airway throughout the entire respiratory cycle (inspiration and expiration). Normal: 5-10 cmH2O. Obstructive disease: 10-20 cmH2O. ARDS: 15-30 cmH2O. Signup and view all the answers

What is barotrauma in the context of mechanical ventilation?

Barotrauma is lung injury caused by excessive pressure within the airways and alveoli, potentially leading to conditions like pneumothorax, pneumomediastinum, or subcutaneous emphysema. Signup and view all the answers

What is PEEP, and what are its main effects?

Positive End Expiratory Pressure (PEEP) is the application of pressure above atmospheric pressure maintained in the airways at the end of expiration. Effects include: improving oxygenation (by recruiting alveoli and increasing FRC), potentially decreasing blood pressure (due to reduced venous return), and increasing functional residual capacity (FRC). Signup and view all the answers

Increasing PEEP generally improves ventilation (CO2 removal).

False (B) Signup and view all the answers

When might PEEP be contraindicated or used with caution?

Contraindications or cautions include: Hemodynamic instability (low blood pressure, cardiac compromise) as PEEP can worsen it, untreated pneumothorax, and head trauma with increased intracranial pressure (ICP). Signup and view all the answers

After optimizing FiO2 to approximately _____%, further improvements in oxygenation are often sought by increasing PEEP.

60 Signup and view all the answers

What is the formula relating Volume, Flow, and Inspiratory Time?

Flow (L/min) / 60 = Tidal Volume (L) / Inspiratory Time (sec). Or rearranged: Tidal Volume (L) = [Flow (L/min) / 60] * Inspiratory Time (sec). Signup and view all the answers

What is a pressure limit on a ventilator, and what is its purpose?

A pressure limit is a set maximum airway pressure that the ventilator will not exceed during inspiration. Its purpose is to protect the patient's lungs from injury due to excessive pressure (barotrauma). Signup and view all the answers

What is the I:E ratio, and what are typical ratios for normal lungs, restrictive disease, and obstructive disease?

The Inspiratory:Expiratory (I:E) ratio represents the ratio of inspiratory time (Ti) to expiratory time (Te) within one breath cycle, expressed in parts, not seconds. Normal: ~1:2 to 1:3. Restrictive (e.g., ARDS): Often shorter Te, like 1:1.5 or 1:2. Obstructive (e.g., COPD): Requires longer Te, like 1:4 or 1:6, to allow adequate exhalation. Signup and view all the answers

What is Peak Inspiratory Pressure (PIP)?

Peak Inspiratory Pressure (PIP) is the maximum pressure measured in the airway during inspiration while on mechanical ventilation. Signup and view all the answers

A high Peak Inspiratory Pressure (PIP), generally considered >_____cmH2O, often indicates increased airway resistance or decreased lung compliance.

30-35 Signup and view all the answers

What is Plateau Pressure (Pplat), how is it measured, and what does it primarily reflect?

Plateau Pressure (Pplat) is the pressure measured in the airway at the end of inspiration during a brief pause (inspiratory hold or pause), when there is no airflow. It primarily reflects the static compliance (elastic recoil pressure) of the lungs and chest wall at the delivered tidal volume. Signup and view all the answers

To minimize Ventilator-Induced Lung Injury (VILI), Plateau Pressure (Pplat) should ideally be kept below _____ cmH2O.

30 Signup and view all the answers

What is Airway Resistance (Raw), how is it calculated, and what is the normal range?

Airway Resistance (Raw) is the opposition to airflow within the conducting airways. It is calculated as the pressure difference between PIP and Pplat divided by the flow rate (in L/sec): Raw = (PIP - Pplat) / Flow. The normal range is typically 0.6-2.4 cmH2O/L/sec. Signup and view all the answers

What is trigger sensitivity on a ventilator, and what are the two main types?

Trigger sensitivity determines how much effort a patient must exert to initiate (trigger) a ventilator-assisted breath. The two main types are Pressure Triggering (detects a drop in airway pressure) and Flow Triggering (detects a change in baseline flow). Signup and view all the answers

What do 'modes' of ventilation define?

Modes of ventilation define the pattern of interaction between the patient and the ventilator, specifically determining how breaths are triggered (started), limited (controlled during inspiration), and cycled (ended). Signup and view all the answers

Describe Volume Control-Continuous Mandatory Ventilation (VC-CMV), also known as Assist/Control (A/C).

In VC-CMV (A/C), every breath delivered is a mandatory breath with a preset tidal volume. Breaths can be triggered either by the patient's inspiratory effort (assist) or by the ventilator at a set time interval (control) if the patient doesn't trigger. The delivered volume is constant, but airway pressure varies. Signup and view all the answers

Describe Volume Control-Synchronized Intermittent Mandatory Ventilation (VC-SIMV).

In VC-SIMV, the ventilator delivers a set number of mandatory breaths with a preset tidal volume, synchronized with the patient's effort if possible. Between mandatory breaths, the patient can breathe spontaneously, potentially with pressure support (PS). Signup and view all the answers

Describe Pressure Control-Continuous Mandatory Ventilation (PC-CMV), also known as Pressure Assist/Control (PC-A/C).

In PC-CMV (A/C), every breath delivered is a mandatory breath with a preset inspiratory pressure level and inspiratory time (Ti). Breaths can be triggered by the patient (assist) or by time (control). The inspiratory pressure is constant, but the tidal volume delivered varies based on lung compliance and resistance. Signup and view all the answers

Describe Pressure Control-Synchronized Intermittent Mandatory Ventilation (PC-SIMV).

In PC-SIMV, the ventilator delivers a set number of mandatory breaths with a preset inspiratory pressure and time, synchronized with patient effort. Between mandatory breaths, the patient can breathe spontaneously, often with added pressure support (PS). Signup and view all the answers

What are 'Dual Modes' of ventilation, such as Pressure Regulated Volume Control (PRVC)?

Dual modes combine aspects of volume and pressure control. For example, PRVC (or similar modes like VC+) aims to deliver a target tidal volume using the lowest possible inspiratory pressure, adjusting the pressure breath-by-breath based on the previous breath's delivered volume and lung mechanics. Signup and view all the answers

Describe High-Frequency Oscillatory Ventilation (HFOV).

HFOV delivers very small tidal volumes (often less than dead space) at extremely high respiratory rates (frequencies measured in Hertz) while maintaining a constant mean airway pressure. Gas exchange occurs through complex mechanisms like bulk flow, Taylor dispersion, and pendelluft. Signup and view all the answers

What is Non-Invasive Ventilation (NIV), and what are its common types and indications?

NIV provides ventilatory support without an artificial airway (like an ETT or trach). Common types include CPAP and Bi-level Positive Airway Pressure (BiPAP/BPAP), delivered via face mask or nasal mask. Indications include COPD exacerbations, cardiogenic pulmonary edema, weaning from invasive ventilation, and sleep apnea. Signup and view all the answers

List common causes for a low-pressure alarm on a mechanical ventilator.

Circuit disconnection or leak (most common), ETT cuff leak or rupture, extubation, chest tube leak (if applicable), or inadequate flow/volume settings. Signup and view all the answers

List common causes for a low exhaled volume alarm on a mechanical ventilator.

Circuit leak or disconnection, ETT cuff leak, decreased lung compliance causing pressure limiting (in volume control), increased airway resistance causing pressure limiting, inadequate ventilator settings, or patient disconnection (e.g., accidental extubation). Signup and view all the answers

List common causes for a high respiratory rate alarm on a mechanical ventilator.

Increased patient effort or anxiety, pain, hypoxia, hypercapnia, metabolic acidosis, fever, inadequate ventilator settings (e.g., insufficient flow or sensitivity issues leading to auto-triggering), or neurological changes. Signup and view all the answers

What does an apnea alarm indicate, and what are common causes?

An apnea alarm indicates that the patient has not initiated a breath (or the ventilator has not detected a breath) within a preset time interval. Common causes include central nervous system depression (e.g., sedation, neurological injury), respiratory muscle fatigue, or problems with ventilator sensitivity settings. Signup and view all the answers

List key objective criteria often used to assess readiness for weaning from mechanical ventilation.

Resolution or significant improvement of the underlying cause for ventilation, hemodynamic stability (adequate BP, heart rate, no significant arrhythmias or vasoactive drug requirements), adequate oxygenation (e.g., PaO2/FiO2 > 150-200, PEEP <= 5-8 cmH2O, FiO2 <= 0.4-0.5), acceptable acid-base status (pH >= 7.25), adequate respiratory muscle strength (e.g., MIP/NIF > -20 to -30 cmH2O), acceptable Rapid Shallow Breathing Index (RSBI < 105 breaths/min/L), and ability to initiate an inspiratory effort. Signup and view all the answers

What is a Spontaneous Breathing Trial (SBT), and what constitutes failure?

An SBT is a diagnostic test where the patient breathes with minimal or no ventilator support (e.g., low PSV, CPAP, or T-piece) for a set period (typically 30-120 minutes) to assess their ability to sustain independent breathing. Failure criteria include: tachypnea (RR > 35/min), hypoxemia (SpO2 < 90%), tachycardia (HR > 140/min or sustained >20% increase), bradycardia, hypertension or hypotension, changes in mental status (anxiety, agitation, somnolence), or diaphoresis. Signup and view all the answers

What criteria should be met for safe extubation after a successful SBT?

Successful completion of an SBT, ability to protect the airway (presence of gag/cough reflex, adequate level of consciousness), ability to clear secretions effectively, and hemodynamic stability. Signup and view all the answers

What are the main components analyzed in an Arterial Blood Gas (ABG) sample?

pH (acidity/alkalinity), PaCO2 (partial pressure of carbon dioxide, reflecting ventilation), PaO2 (partial pressure of oxygen, reflecting oxygenation), HCO3- (bicarbonate, reflecting metabolic component), and SaO2/SpO2 (oxygen saturation). Signup and view all the answers

Normal arterial blood gas values are typically: pH -, PaCO2 - mmHg, PaO2 - mmHg (room air), HCO3 - mEq/L.

7.35-7.45, 35-45, 80-100, 22-26 Signup and view all the answers

In weaning criteria, an adequate PaO2/FiO2 ratio is considered >, acceptable respiratory rate </min, tidal volume >___ ml/kg, minute ventilation <_ L/min, MIP/NIF >_ cmH2O (more negative), and RSBI <___ breaths/min/L.

150-200, 35, 5, 10, -20 to -30, 105 Signup and view all the answers

What are 'scalars' in the context of mechanical ventilator graphics?

Scalars are graphical displays plotting a single respiratory variable (Pressure, Flow, or Volume) against Time. Signup and view all the answers

What are 'loops' in the context of mechanical ventilator graphics, and what are the two main types?

Loops display the relationship between two respiratory variables simultaneously during a breath cycle. The two main types are the Pressure-Volume (P-V) loop and the Flow-Volume (F-V) loop. Signup and view all the answers

How do loops differ from scalars on a ventilator display?

Scalars plot a single variable (Pressure, Flow, or Volume) against Time. Loops plot the relationship between two variables simultaneously (Pressure vs. Volume, or Flow vs. Volume) over the course of a breath, not directly against time. Signup and view all the answers

What does OPA stand for and what are its main indications?

OPA stands for Oropharyngeal Airway. Its main indications are to relieve upper airway obstruction if airway maneuvers fail, assist with bag-mask ventilation, and serve as a bite block in intubated patients. The patient must be unconscious/non-responsive. Signup and view all the answers

What does NPA stand for and when is it indicated?

NPA stands for Nasopharyngeal Airway. It is indicated to facilitate ventilation, especially with jaw/mouth trauma, during bag-mask ventilation, for heavy secretion removal, and can be used in conscious patients. It may also be placed for frequent nasotracheal (NT) suctioning. Signup and view all the answers

What is an LMA and what is its primary function?

LMA stands for Laryngeal Mask Airway. It provides a seal at the opening of the trachea and esophagus, serving as an alternative airway to an endotracheal tube (ETT). Signup and view all the answers

What does ETT stand for, and what are common adult sizes and ideal cuff pressures?

ETT stands for Endotracheal Tube. Common adult sizes are 6.5-7.5mm for females (placed at 20-22 cm depth) and 7.5-8.5mm for males (placed at 22-24 cm depth). The ideal cuff pressure is 25 cmH2O, with a maximum of 30 cmH2O. Signup and view all the answers

Explain the Minimal Occlusion Technique (MOV) for ETT cuff inflation.

Inflate the cuff slowly while listening over the trachea during a positive pressure breath (end-inspiration) until the air leak just stops. Signup and view all the answers

Explain the Minimal Leak Technique (MLT) for ETT cuff inflation.

Inflate the cuff until the leak stops (like MOV), then slowly remove a small amount of air until a slight leak is heard at peak inspiration. Then, slightly reinflate just until the leak stops again. Signup and view all the answers

What are the main objectives of mechanical ventilation?

The primary objectives are to: 1. Improve ventilation (primarily CO2 removal) and then oxygenation. 2. Decrease the work of breathing (WOB). 3. Improve acid-base imbalances (correct respiratory acidosis). 4. Assist in improving metabolic issues (compensate for metabolic acidosis/alkalosis). Signup and view all the answers

What are typical initial settings for mechanical ventilation in an adult?

Typical initial settings include: Tidal Volume (Vt): 6-8 ml/kg (based on IBW). Respiratory Rate (f): 12-20 breaths/min. FiO2: 100% in emergencies, otherwise start at 40% or match pre-MV O2 level. I:E Ratio: Based on lung condition (e.g., 1:2 normal/ARDS, 1:4 COPD). PEEP: 5 cmH2O. Mode: Varies based on desired control. Signup and view all the answers

Define the terms 'Trigger', 'Cycle', 'Sensitivity', and 'Limit' in the context of a ventilator breath cycle.

Trigger: What initiates the start of a breath (e.g., time, patient effort). Cycle: What causes the ventilator to end inspiration (e.g., volume, time, flow). Sensitivity: How much patient effort is required to trigger a breath. Limit: A preset maximum value (e.g., pressure, volume, flow) that is reached during inspiration but does not end the inspiratory phase. Signup and view all the answers

In controlled ventilation modes without spontaneous effort, what determines when the ventilator delivers a breath?

Time determines when the ventilator delivers a breath. The set respiratory rate dictates the time interval between mandatory breaths. Signup and view all the answers

Define lung compliance and describe the difference between high and low compliance.

Compliance refers to the distensibility of the lungs and chest wall; essentially, how easily the lungs can inflate (change in volume per unit change in pressure). High compliance means the lungs inflate easily but may have poor elastic recoil (hard to exhale, e.g., emphysema). Low compliance means the lungs are stiff and difficult to inflate (e.g., ARDS, fibrosis). Signup and view all the answers

List factors that can influence lung compliance.

Factors influencing compliance include: 1. The inherent stiffness or elasticity of the lung tissue (e.g., fibrosis decreases compliance). 2. Muscular tension of the chest wall. 3. Presence of secretions or fluid in the lungs (decreases compliance). 4. Alveolar surface tension (surfactant deficiency decreases compliance). Signup and view all the answers

Define pressure in the context of respiratory mechanics and state its common units.

Pressure is the force exerted by gases within the airways and lungs. It is commonly measured in centimeters of water (cmH2O) for ventilator settings and airway pressures, or sometimes millimeters of mercury (mmHg) for blood gas pressures. Signup and view all the answers

Define flow in the context of respiratory mechanics and state its common units.

Flow is the rate at which air moves into or out of the lungs. It is typically measured in liters per minute (L/min) or sometimes liters per second (L/sec). Signup and view all the answers

What is Mean Airway Pressure (MAP) and what are its typical ranges in different conditions?

Mean Airway Pressure (MAP) is the average pressure applied to the airways and lungs throughout the entire respiratory cycle (inspiration and expiration). Normal MAP is typically 5-10 cmH2O. In patients with obstructive disease, it might be 10-20 cmH2O. In ARDS, it can be significantly higher, often 15-30 cmH2O or more. Signup and view all the answers

What is PEEP, its effect on oxygenation and blood pressure, and when should it generally be increased?

PEEP stands for Positive End Expiratory Pressure, which is pressure maintained in the airways at the end of exhalation. Increased levels help recruit collapsed alveoli and improve oxygenation by increasing Functional Residual Capacity (FRC). However, PEEP can also decrease venous return and potentially lower blood pressure (BP). PEEP is generally increased after FiO2 reaches 60% if oxygenation targets are still not met. Signup and view all the answers

What is the relationship between flow rate, tidal volume, and inspiratory time?

The relationship is: Flow (L/min) / 60 = Tidal Volume (Vt) (L) / Inspiratory Time (I time) (sec). Rearranging, $Vt = Flow imes I time$. Note consistent units are crucial (L/min vs L/sec). Signup and view all the answers

What is a Pressure Limit on a ventilator and its purpose?

A Pressure Limit is a preset maximum airway pressure that the ventilator will not exceed during inspiration. Its main purpose is to protect the patient's lungs from injury due to excessive pressure (barotrauma). Signup and view all the answers

Define Total Cycle Time (TCT) and provide the formula for calculating it.

Total Cycle Time (TCT) is the duration of one complete respiratory cycle, from the start of one breath to the start of the next breath. It includes both inspiratory time (Ti) and expiratory time (Te). TCT is calculated by dividing 60 seconds by the Respiratory Rate (RR): $TCT = 60 / RR$. Signup and view all the answers

What is the I:E Ratio, and what are typical ratios for normal, restrictive, and obstructive lung conditions?

The I:E Ratio represents the ratio of the duration of inspiration to the duration of expiration, expressed in parts, not absolute seconds. A normal ratio is often 1:2 or 1:3. For restrictive diseases (like ARDS), a ratio of 1:2 or even 1:1 might be used to maximize time for gas exchange. For obstructive diseases (like COPD), a longer expiratory time is needed, so ratios like 1:4, 1:5, or 1:6 are used to prevent air trapping. Signup and view all the answers

Define Peak Inspiratory Pressure (PIP). What does a high PIP generally indicate?

Peak Inspiratory Pressure (PIP) is the maximum pressure reached in the airways during ventilator-delivered inspiration. It reflects the pressure needed to overcome both airway resistance and the elastic recoil of the lungs and chest wall. A high PIP (often considered >30-35 cmH2O, but context matters) generally indicates increased resistance or decreased compliance. Signup and view all the answers

Define Airway Resistance (Raw), state the formula, normal range, and causes of increased Raw.

Airway Resistance (Raw) is the opposition to airflow within the airways. It is calculated as the difference between Peak Inspiratory Pressure (PIP) and Plateau Pressure (Pplat), divided by the flow rate (typically in L/sec). Formula: $Raw = (PIP - Pplat) / Flow$. Normal Raw is typically 0.6 - 2.4 cmH2O/L/sec. Increased Raw can be caused by bronchospasm, secretions, airway edema, or issues with the artificial airway (e.g., kinked or narrow ETT). Signup and view all the answers

Define Static Compliance (CL or Cstat), state the formula, normal range, and causes of decreased CL.

Static Compliance (CL or Cstat) measures the distensibility of the respiratory system (lungs and chest wall) under conditions of no airflow. It is calculated by dividing the delivered Tidal Volume (Vt) by the difference between Plateau Pressure (Pplat) and PEEP. Formula: $CL = Vt / (Pplat - PEEP)$. Normal static compliance is typically 60-100 mL/cmH2O. Decreased CL (stiff lungs) occurs in conditions like ARDS, pneumonia, atelectasis, pulmonary edema, fibrosis, pneumothorax, and abdominal distension. Signup and view all the answers

What is Auto-PEEP (Intrinsic PEEP)?

Auto-PEEP, also known as intrinsic PEEP or dynamic hyperinflation, is trapped air pressure remaining in the alveoli at the end of exhalation because the patient did not have sufficient time to exhale completely before the next breath begins. Signup and view all the answers

Match the basic mode of ventilation with its description:

CMV (Continuous Mandatory Ventilation) = All breaths are mandatory (delivered by the ventilator), regardless of patient effort. SIMV (Synchronized Intermittent Mandatory Ventilation) = Delivers a set number of mandatory breaths synchronized with patient effort, allowing spontaneous breaths between mandatory ones. Spont/CPAP (Spontaneous/Continuous Positive Airway Pressure) = Patient breathes entirely spontaneously, ventilator provides PEEP/CPAP and potentially pressure support. PSV (Pressure Support Ventilation) = Provides a set pressure support level to augment patient's spontaneous breaths. Signup and view all the answers

Describe Continuous Mandatory Ventilation (CMV). What are common sub-types?

CMV is a mode where the ventilator delivers all breaths at preset parameters (volume or pressure, rate, time). Patient effort may trigger a mandatory breath (Assist/Control) or be ignored (Control). Common subtypes include Volume Control (VC-CMV or VC-A/C) where a set volume is delivered, and Pressure Control (PC-CMV or PC-A/C) where a set pressure is delivered for a set time. Signup and view all the answers

What parameters are typically set in Volume Control - Assist/Control (VC/AC) ventilation?

In VC/AC, the clinician typically sets: Tidal Volume (Vt), Respiratory Rate (f), FiO2, PEEP, and often Flow rate or Inspiratory Time (Ti) and flow pattern. Signup and view all the answers

What parameters are typically set in Pressure Control - Assist/Control (PC/AC) ventilation?

In PC/AC, the clinician typically sets: Inspiratory Pressure level, Inspiratory Time (Ti), Respiratory Rate (f), FiO2, and PEEP. Signup and view all the answers

What characterizes a Spontaneous mode of ventilation?

In a spontaneous mode, the patient initiates and controls the timing and depth (tidal volume) of all breaths. The ventilator provides support like CPAP (Continuous Positive Airway Pressure) or PSV (Pressure Support Ventilation) but does not deliver mandatory breaths based on a set rate. Signup and view all the answers

What is CPAP and how is it primarily used in invasive ventilation?

CPAP (Continuous Positive Airway Pressure) provides a constant level of positive pressure throughout the entire respiratory cycle (inspiration and expiration) for spontaneously breathing patients. In invasive ventilation, it primarily functions like PEEP for spontaneous breaths, helping to maintain alveolar recruitment and improve oxygenation. Signup and view all the answers

What is Pressure Regulated Volume Control (PRVC)?

PRVC is a hybrid mode of ventilation often considered a form of Assist/Control. The clinician sets a target Tidal Volume (Vt), RR, I-time, FiO2, and PEEP. The ventilator delivers pressure-controlled breaths, automatically adjusting the inspiratory pressure breath-by-breath to achieve the target Vt using the lowest possible pressure. Signup and view all the answers

Compare Volume Control (VC) and Pressure Control (PC) ventilation regarding set parameters and variable outcomes.

In Volume Control (VC): You set Tidal Volume and Flow (or I-time). Airway Pressure (PIP, Pplat) varies based on lung mechanics (R&C). Guarantees minute ventilation. In Pressure Control (PC): You set Inspiratory Pressure and Inspiratory Time. Tidal Volume varies based on lung mechanics (R&C) and patient effort. May limit peak pressures more effectively. Signup and view all the answers

List common causes for a High Pressure ventilator alarm.

Common causes include: Increased Airway Resistance (secretions, bronchospasm, kinked ETT, patient biting tube), Decreased Compliance (ARDS, pneumonia, pneumothorax, pulmonary edema, abdominal distension), or ventilator synchrony issues (patient coughing, fighting the ventilator). Signup and view all the answers

List common causes for a Low Pressure or Low Volume ventilator alarm.

Common causes include: Circuit Leaks (disconnected tubing, cuff leak/deflation, chest tube leak), inadequate flow or pressure settings, or improvement in patient's lung compliance/resistance (less common cause for alarm). Signup and view all the answers

List common causes for a High Respiratory Rate ventilator alarm.

Common causes include: Increased patient respiratory drive (hypoxia, hypercapnia, pain, anxiety, fever, metabolic acidosis), inappropriate ventilator sensitivity settings (auto-triggering), or patient attempting to overcome inadequate ventilator support. Signup and view all the answers

What steps should be taken immediately when a HIGH pressure alarm sounds?

<ol> <li>Disconnect the patient from the ventilator and begin manual ventilation with a resuscitation bag and 100% O2. 2. Assess the patient (chest rise, breath sounds). 3. Suction the patient if secretions are suspected. 4. Check the ETT for kinks or obstructions (e.g., pass suction catheter). 5. Check ventilator circuit for kinks or water. 6. Consider causes like bronchospasm, pneumothorax, mainstem intubation, decreased compliance, patient agitation.</li> </ol> Signup and view all the answers

What steps should be taken when a LOW pressure or LOW volume alarm sounds?

<ol> <li>Check all connections from the ventilator to the patient's ETT for leaks or disconnections. 2. Check the ETT cuff pilot balloon and inflate if necessary, listening for leaks. 3. Assess for significant leaks around the ETT at the mouth. 4. Check the ventilator circuit for holes or damage. 5. Consider if settings are appropriate (e.g., low pressure limit set too high).</li> </ol> Signup and view all the answers

Define weaning from mechanical ventilation.

Weaning is the gradual process of reducing ventilator support and allowing the patient to resume spontaneous breathing, ultimately leading to liberation from mechanical ventilation (extubation). Signup and view all the answers

List key weaning parameters or criteria used to assess readiness for liberation from mechanical ventilation.

Key criteria include: Resolution or improvement of underlying cause for MV, adequate oxygenation (e.g., PaO2 > 60 mmHg on FiO2 40%, PEEP 5-8 cmH2O), hemodynamic stability, adequate respiratory muscle strength (NIF/MIP > -20 to -30 cmH2O), acceptable spontaneous breathing pattern and rate, adequate cough and airway clearance, and acceptable Rapid Shallow Breathing Index (RSBI < 105). Signup and view all the answers

What is the Rapid Shallow Breathing Index (RSBI) and how is it calculated? What value indicates readiness for weaning?

RSBI assesses the efficiency of spontaneous breathing. It is calculated by dividing the spontaneous respiratory rate (f) by the spontaneous tidal volume (Vt) in liters. Formula: $RSBI = f / Vt (L)$. An RSBI value less than 105 breaths/min/L generally indicates a higher likelihood of successful weaning. Signup and view all the answers

What is NIF or MIP, and what value typically suggests adequate respiratory muscle strength for weaning?

NIF (Negative Inspiratory Force) or MIP (Maximal Inspiratory Pressure) measures the maximum negative pressure a patient can generate during a forced inhalation against an occluded airway. It reflects respiratory muscle strength. A value more negative than -20 cmH2O (e.g., -25, -30 cmH2O) generally indicates adequate strength for weaning. Signup and view all the answers

What are generally acceptable ABG parameters before considering weaning or extubation?

Generally acceptable parameters include: pH within normal range or baseline for the patient (often > 7.35, but acceptable < 7.25 is sometimes cited as an indication for MV, not weaning), PaCO2 close to patient's baseline (typically < 50 mmHg unless known CO2 retainer), and PaO2 > 60 mmHg on FiO2 40-50%. Signup and view all the answers

What are 'Scalars' in mechanical ventilation graphics?

Scalars are graphical representations plotting a single ventilation variable (Pressure, Flow, or Volume) against Time. There are Pressure-Time, Flow-Time, and Volume-Time scalars. Signup and view all the answers

What are 'Loops' in mechanical ventilation graphics, and what are the two main types?

Loops are graphical representations that display the relationship between two ventilation variables simultaneously during a respiratory cycle. The two main types are the Pressure-Volume (P-V) loop (Volume on Y-axis, Pressure on X-axis) and the Flow-Volume (F-V) loop (Flow on Y-axis, Volume on X-axis). Signup and view all the answers

What is the key difference between Scalars and Loops on a ventilator display?

Scalars display a single parameter (Pressure, Flow, or Volume) plotted against Time. Loops display the relationship between two parameters simultaneously (Pressure vs. Volume, or Flow vs. Volume) over the course of a breath cycle, independent of time. Signup and view all the answers

Flashcards

OPA

Oropharyngeal Airway. Used to relieve upper airway obstruction or as a bite block in intubated patients. Only for unconscious/non-responsive patients.

NPA

Nasopharyngeal Airway. Facilitates ventilation and secretion removal. Can be used in conscious patients.

LMA

Laryngeal Mask Airway. Provides a seal at the trachea and esophagus. Alternative to ETT.

ETT

Endotracheal Tube. Common sizes: Female 6.5-7.5mm (20-22 cm), Male 7.5-8.5mm (22-24 cm). Ideal cuff pressure: 25 cmH20.