a) It is having 10 times more affinity than oxygen b) 60 percent is not deadly. c) . Concentration above 10% are dangerous and need observation d) Concentration above 10% are dangerous and need treatment with pure oxygen for more than 24 hours
d
Option A: Affinity of CO for Hb is 200-250 times that of oxygen. It causes a conformational change in Hb molecule and reduces affinity of Hb for O2, shifting the oxyhemoglobin dissociation curve to the left.
Option B: Concentrations less than 10% are usually asymptomatic. Concentrations >60% are fatal. Arterial carboxyhemoglobin level must be obtained because pulse oximetry can be falsely elevated.
Option C: Concentrations above 10 per cent are dangerous and need treatment with pure oxygen for more than 24 hours. Administration of 100% O2 reduces the half-life of CO from 250 minutes in room air to 40 to 60 minutes on 100% oxygen.
Q) A 40-year-old man presents 4 days after severe vomiting with chest pain, fever, and breathlessness. On examination, his pulse is 110/min and blood pressure is 110/80 mmHg. Chest X-ray and CT scan show a left-sided pleural effusion with mediastinal air, suggestive of an esophageal perforation diagnosed approximately 96 hours after onset. What is the best management option?
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Q) All are true about compartment syndrome of limb except?
a) Diagnosis is unlikely if pulse is felt distally
b) There is pain on passive stretching of the limb
c) Pain is out of proportion to the signs
d) Muscles of calf and forearm are commonly involved
Correct Answer: a) Diagnosis is unlikely if pulse is felt distally
Explanation:
Compartment syndrome occurs when hydrostatic pressure within a fascial compartment increases enough to compromise circulation, leading to muscle ischemia and necrosis.
- The calf, forearm, hand, and foot muscles are most commonly involved.
- It is a clinical diagnosis with key features: severe pain out of proportion to the signs, increasing pain, and pain on passive stretch.
- Other late signs include paralysis, paresthesia, pallor, and pulselessness (which is an extremely late sign).
- Importantly, peripheral pulses are generally not affected early. This means a patient can still have palpable distal pulses despite having compartment syndrome.
- Diagnostic thresholds include: absolute compartment pressure ≥30 mmHg or a delta pressure (diastolic BP – compartment pressure) ≤30 mmHg.
Q) Gaze paresis is seen after head injury? What is responsible for this
a) Facial nerve injury
b) Vestibulo cochlear nerve injury
c) Brain stem dysfunction
d) Optic nerve injury
Gaze paresis is inability to produce horizontal eye movements in one or both directions. Examination of cranial nerves in head injury is very important to fully assess the extent of injury.