Mask Ventilation — MCQs
Highest concentration of oxygen is delivered through?
A patient admitted after a road traffic accident is put on mechanical ventilation. He opens his eyes on verbal command and moves all four limbs spontaneously. Calculate his GCS.
Patient with BMI 40 presents for emergency surgery. All are correct about airway management EXCEPT:
A patient is admitted following a road traffic accident. He has sustained significant blunt injury to his head, chest and abdomen and has a Glasgow Coma Scale score of 8/15. His saturations are poor at 89% on 15 L of oxygen a rebreathing mask. You note bruising around both eyes and blood-stained fluid issuing from his left ear, which forms concentric circles when dripped on a white sheet. You wish to support his airway to improve oxygenation. The first choice of airway adjunct would be
Following a knife injury to the face causing facial nerve damage, secretion from which of the following glands would be LEAST likely to be impaired?
Which of the following statements about the laryngeal mask airway (LMA) is false?
Which of the following is an ideal method to prevent aspiration pneumonia?
A Patient in medical intensive care unit who is intubated, suddenly removes the endotracheal tube. What should be done next?
A 30-year-old male was intubated for surgery. What is the best method to confirm the correct position of the endotracheal tube?
Which of the following conditions are contraindications for noninvasive positive-pressure ventilation in patients with respiratory failure? I. Craniofacial abnormalities II. Significant burns III. Respiratory failure with PaCO_2 of 60 mm Hg IV. Cardiovascular instability Select the correct answer using the code given below :
Mask Ventilation Indian Medical PG Practice Questions and MCQs
Question 1: Highest concentration of oxygen is delivered through?
- A. Bag and mask
- B. Venturi mask
- C. Nasal cannula
- D. Mask with reservoir (Correct Answer)
Explanation: ***Mask with reservoir*** - A mask with a reservoir bag, particularly a **non-rebreather mask**, delivers the highest concentration of oxygen (up to 95-100%). - The **reservoir bag** and **one-way valves** prevent entrainment of room air and re-breathing of exhaled CO2, maximizing oxygen delivery. *Bag and mask* - While capable of delivering high oxygen concentrations, its effectiveness is highly dependent on a **proper seal** and the technique of the rescuer. - Its primary role is for **manual ventilation** rather than sustained high-concentration oxygen delivery alone. *Venturi mask* - The Venturi mask is known for delivering **precise and controlled oxygen concentrations**, not necessarily the highest. - It uses a jet of oxygen to entrain fixed amounts of room air, maintaining a **consistent FiO2** (fraction of inspired oxygen). *Nasal cannula* - A nasal cannula delivers relatively **low concentrations of oxygen** (24-44%), as it mixes with a large volume of room air. - It is suitable for **mild to moderate hypoxemia** but cannot provide the high FiO2 needed in critical situations.
Question 2: A patient admitted after a road traffic accident is put on mechanical ventilation. He opens his eyes on verbal command and moves all four limbs spontaneously. Calculate his GCS.
- A. Eyes-3, Verbal -NT, Motor-6 (Correct Answer)
- B. Eyes -3, Verbal-1, Motor -6
- C. Eyes-2, Verbal -1, Motor -5
- D. Eyes-2, Verbal -NT, Motor -5
Explanation: ***Eyes-3, Verbal -NT, Motor-6*** - **Eyes opening to verbal command** scores 3 points on the GCS [1]. - The patient is on **mechanical ventilation**, meaning their verbal response cannot be assessed, leading to a "Non-Testable" (NT) score for verbal [1]. **Spontaneous movement of all four limbs** indicates full motor function, scoring 6 points [2]. *Eyes -3, Verbal-1, Motor -6* - While **eyes opening to verbal command** (3 points) and **spontaneous motor movement** (6 points) are correct, a verbal score of 1 implies **no verbal response** if the patient were able to speak, which is not applicable here due to mechanical ventilation. *Eyes-2, Verbal -1, Motor -5* - **Eyes opening to pain** scores 2, but the patient responded to verbal command. A verbal score of 1 is for no response, and a motor score of 5 indicates localizing to pain, not spontaneous movement. *Eyes-2, Verbal -NT, Motor -5* - **Eyes opening to pain** scores 2, but the patient responded to verbal command (3 points). While **Verbal-NT** is correct due to mechanical ventilation, a motor score of 5 (localizes to pain) is incorrect, as the patient moved limbs spontaneously (6 points).
Question 3: Patient with BMI 40 presents for emergency surgery. All are correct about airway management EXCEPT:
- A. Extended ramping
- B. Avoid cricoid pressure (Correct Answer)
- C. Rapid sequence induction
- D. Avoid preoxygenation
Explanation: ***Avoid cricoid pressure*** - While **cricoid pressure** (Sellick's maneuver) is used to prevent **aspiration** by compressing the esophagus, its effectiveness in **obese patients** is highly debated and often hindered by excess neck tissue. - In obese patients, cricoid pressure can actually worsen the view during laryngoscopy, making intubation more difficult and potentially causing airway trauma. *Extended ramping* - **Ramping** the patient, where the head and shoulders are elevated, is crucial in **obese patients** to align the **oral, pharyngeal, and laryngeal axes**. - This position improves the view during laryngoscopy and facilitates successful intubation by effectively displacing excess tissue. *Rapid sequence induction* - **Rapid sequence induction (RSI)** is often indicated in **obese patients** undergoing emergency surgery due to their increased risk of **gastric reflux** and **pulmonary aspiration**. - RSI involves administering a sedative and a paralytic agent in rapid succession, followed immediately by intubation, to minimize the time the airway is unprotected. *Avoid preoxygenation* - **Preoxygenation** is essential in **obese patients** to maximize their **oxygen reserves** before intubation. - Obese patients have reduced **functional residual capacity (FRC)** and increased **oxygen consumption**, making them desaturate rapidly during apnea, so preoxygenation significantly prolongs safe apnea time.
Question 4: A patient is admitted following a road traffic accident. He has sustained significant blunt injury to his head, chest and abdomen and has a Glasgow Coma Scale score of 8/15. His saturations are poor at 89% on 15 L of oxygen a rebreathing mask. You note bruising around both eyes and blood-stained fluid issuing from his left ear, which forms concentric circles when dripped on a white sheet. You wish to support his airway to improve oxygenation. The first choice of airway adjunct would be
- A. Nasopharyngeal tube
- B. Intubation
- C. Laryngeal mask
- D. Oropharyngeal airway (Correct Answer)
Explanation: ***Oropharyngeal airway*** - An **oropharyngeal airway (OPA)** is the most appropriate initial airway adjunct in a patient with a **depressed GCS (8/15)** and poor oxygenation, as it helps to relieve **upper airway obstruction** caused by the tongue falling back. - Given the potential for a **basal skull fracture** (bruising around eyes, blood-stained fluid from ear forming concentric circles), a **nasopharyngeal airway (NPA)** is contraindicated due to the risk of intracranial insertion. *Nasopharyngeal tube* - A **nasopharyngeal airway (NPA)** is contraindicated in this patient due to signs suggestive of a **basal skull fracture**, which include **raccoon eyes (periorbital bruising)** and **Battle's sign (bruising behind the ear)**, as well as the **halo sign (concentric circles of blood and CSF)** from the ear. - Inserting an NPA in such a scenario risks inadvertently entering the **cranial cavity**, leading to further neurological damage or infection. *Intubation* - While **intubation** may eventually be necessary given the patient's low GCS and poor oxygenation, it is not the *first choice* of airway adjunct. - The immediate priority is to establish a **patent airway** quickly and safely, which an OPA can achieve while preparations for definitive intubation are made. *Laryngeal mask* - A **laryngeal mask airway (LMA)** could be considered for airway management, but it is typically a more advanced adjunct than an OPA. - Its insertion requires a certain level of skill and might be more time-consuming than an OPA, which is crucial in an emergency setting.
Question 5: Following a knife injury to the face causing facial nerve damage, secretion from which of the following glands would be LEAST likely to be impaired?
- A. Parotid gland (Correct Answer)
- B. Sublingual gland
- C. Lacrimal gland
- D. Submandibular gland
Explanation: ***Parotid gland*** - The **parotid gland** receives parasympathetic innervation for secretion via the **glossopharyngeal nerve (CN IX)**, specifically through the **lesser petrosal nerve** → **otic ganglion** → **auriculotemporal nerve**. - The **facial nerve (CN VII)** passes through the parotid gland but does not provide secretomotor innervation, so facial nerve damage would **not impair parotid secretion**. *Sublingual gland* - The **sublingual gland** receives parasympathetic innervation from the **facial nerve (CN VII)** via the **chorda tympani** → **submandibular ganglion**. - Damage to the facial nerve would impair secretion from the sublingual gland. *Lacrimal gland* - The **lacrimal gland** receives parasympathetic innervation from the **facial nerve (CN VII)** via the **greater petrosal nerve** → **pterygopalatine ganglion**. - Damage to the facial nerve would impair tear production from the lacrimal gland, leading to **dry eye** (keratoconjunctivitis sicca). *Submandibular gland* - The **submandibular gland** receives parasympathetic innervation from the **facial nerve (CN VII)** via the **chorda tympani** → **submandibular ganglion**. - Damage to the facial nerve would impair secretion from the submandibular gland.
Question 6: Which of the following statements about the laryngeal mask airway (LMA) is false?
- A. Easy to insert
- B. More invasive
- C. Prevents aspiration (Correct Answer)
- D. More complications
Explanation: ***Prevents aspiration*** - The **laryngeal mask airway (LMA)** is a **supraglottic airway device** that does not fully protect the airway from aspiration. - While it can provide a seal, it does not reliably prevent gastric contents from entering the trachea in cases of regurgitation. *More invasive* - Compared to endotracheal intubation, the **LMA is considered less invasive** as it does not pass through the vocal cords. - It is designed to sit in the **hypopharynx**, sealing around the glottic opening. *Easy to insert* - The **LMA is generally easy to insert** and requires less skill than endotracheal intubation. - It can often be placed quickly and effectively in emergency situations or for short procedures. *More complications* - The **LMA usually has fewer complications** compared to endotracheal intubation, such as less incidence of trauma to the vocal cords or trachea. - While complications like sore throat or nerve injury can occur, they are generally less severe than those associated with intubation.
Question 7: Which of the following is an ideal method to prevent aspiration pneumonia?
- A. Full stomach
- B. Increase the intra abdominal pressure
- C. Inhalational anesthetic
- D. Endotracheal tube (cuffed) (Correct Answer)
Explanation: ***Endotracheal tube (cuffed)*** - A cuffed endotracheal tube forms a **seal** in the trachea, effectively preventing aspiration of gastric contents or oral secretions into the lungs. - This method is particularly crucial before and during surgical procedures involving general anesthesia, where normal airway protective reflexes are abolished. *Full stomach* - A **full stomach** significantly increases the risk of aspiration, as there is more gastric content available to be regurgitated into the airway. - This is a contraindication for immediate induction of general anesthesia and often necessitates a rapid sequence intubation. *Increase the intra abdominal pressure* - Increasing **intra-abdominal pressure** (e.g., due to obesity, insufflation for laparoscopy) can push gastric contents towards the esophagus, thereby increasing the risk of reflux and aspiration. - This effect is undesirable and directly contributes to aspiration risk rather than preventing it. *Inhalational anesthetic* - **Inhalational anesthetics** depress airway reflexes, making the patient more susceptible to aspiration. - While they are essential for maintaining anesthesia, they do not prevent aspiration; rather, other measures like intubation are necessary to counteract their effects.
Question 8: A Patient in medical intensive care unit who is intubated, suddenly removes the endotracheal tube. What should be done next?
- A. Sedate and reintubate
- B. Make him sit and do physiotherapy
- C. Assess the patient and give bag and mask ventilation and look for spontaneous breathing (Correct Answer)
- D. Give bag and mask ventilation and intubate
Explanation: ***Assess the patient and give bag and mask ventilation and look for spontaneous breathing*** - Upon accidental extubation, the immediate priority is to **assess the patient's airway, breathing, and circulation (ABCs)** and ensure oxygenation via **bag-mask ventilation** if needed, while observing for spontaneous breathing efforts. - This step allows for a controlled re-evaluation of the patient's respiratory status and provides time to plan for reintubation if indicated, without rushing into sedating or reintubating a potentially stable patient. *Sedate and reintubate* - While reintubation may ultimately be necessary, sedating and immediately attempting reintubation without prior assessment can be dangerous if the patient has **stable spontaneous breathing** or if there are other contributing factors like **airway swelling** that need to be addressed first. - Rushing to sedate and intubate could lead to complications if the patient's physiology is not fully understood post-extubation. *Make him sit and do physiotherapy* - This option is inappropriate for an intubated patient who has just accidentally self-extubated, as their airway and breathing status are of immediate concern. - Positioning for physiotherapy or performing chest physiotherapy is a secondary concern after ensuring **adequate oxygenation and ventilation** and confirming a stable airway. *Give bag and mask ventilation and intubate* - While bag-mask ventilation is an appropriate immediate step to maintain oxygenation, automatically proceeding to intubation without fully **assessing the patient's spontaneous breathing status** and overall stability is premature. - Some patients might tolerate extubation and breathe adequately on their own, negating the need for immediate reintubation.
Question 9: A 30-year-old male was intubated for surgery. What is the best method to confirm the correct position of the endotracheal tube?
- A. Capnography (Correct Answer)
- B. X-ray chest
- C. Auscultation
- D. Chest expansion
Explanation: ***Capnography*** - **Continuous waveform capnography** directly measures exhaled carbon dioxide, which is present in the trachea but absent in the esophagus. - The presence of a consistent waveform indicates **endotracheal intubation**, making it the most reliable method for immediate confirmation. *X-ray chest* - While an **X-ray chest** can confirm the tube's position within the trachea and its depth, it is not an immediate method and may delay detection of esophageal intubation. - It mainly serves to confirm appropriate depth and exclude complications like **pneumothorax**, rather than primary confirmation of tracheal placement. *Auscultation* - **Auscultation** for bilateral breath sounds in the axillae and absence of sounds over the epigastrium can suggest proper placement, but it can be misleading in noisy environments or with gastric insufflation. - It is a subjective method and does not directly confirm the presence of **CO2** from the lungs. *Chest expansion* - Observing **bilateral chest expansion** is an initial sign of successful ventilation but does not definitively confirm tracheal placement as esophageal intubation can also cause some chest movement. - It is a less reliable indicator compared to direct **CO2 detection**.
Question 10: Which of the following conditions are contraindications for noninvasive positive-pressure ventilation in patients with respiratory failure? I. Craniofacial abnormalities II. Significant burns III. Respiratory failure with PaCO_2 of 60 mm Hg IV. Cardiovascular instability Select the correct answer using the code given below :
- A. I, III and IV
- B. II, III and IV
- C. I, II and IV (Correct Answer)
- D. I, II and III
Explanation: ***I, II and IV*** - **Craniofacial abnormalities** (I) can prevent a proper mask seal, leading to air leaks and ineffective ventilation. - **Significant burns** (II), especially on the face, can make mask application impossible due to pain, skin integrity issues, and infection risk. - **Cardiovascular instability** (IV), such as severe hypotension or active myocardial ischemia, can be worsened by the positive intrathoracic pressure applied by NPPV, which can decrease venous return and cardiac output. *I, III and IV* - While **craniofacial abnormalities** (I) and **cardiovascular instability** (IV) are contraindications, NPPV can be beneficial for **respiratory failure with a PaCO2 of 60 mm Hg** (III) as it helps reduce CO2 levels and avoids intubation. - Therefore, including III as a contraindication makes this option incorrect. *II, III and IV* - **Significant burns** (II) and **cardiovascular instability** (IV) are clear contraindications. However, **respiratory failure with a PaCO2 of 60 mm Hg** (III) is often an indication for NPPV, not a contraindication. - This option incorrectly identifies a key indication as a contraindication. *I, II and III* - **Craniofacial abnormalities** (I) and **significant burns** (II) are valid contraindications for NPPV. - However, **respiratory failure with a PaCO2 of 60 mm Hg** (III) is a common indication for NPPV, especially in conditions like COPD exacerbations, as it helps improve ventilation and reduce hypercapnia.
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