Which of the following is consistent with return of muscle tone adequate to protect the airway from aspiration after reversal from anaesthesia?a) TOF ratio of 0.7b) No fade detectable on Double Burst Tetanic Stimulationc) Return of normal resting minute ventilationd) Five seconds sustained head lift

**Core Concept**
The question tests the understanding of **recovery from neuromuscular blockade** and the criteria for ensuring **airway protection**. Return of adequate muscle tone is crucial for preventing aspiration.

**Why the Correct Answer is Right**
A **sustained head lift** indicates significant recovery of neuromuscular function, suggesting that the patient has regained sufficient muscle strength to protect their airway. This is a clinical sign that correlates with the return of muscle tone adequate for airway protection.

**Why Each Wrong Option is Incorrect**
**Option A:** A TOF (Train-of-Four) ratio of 0.7 is not fully indicative of complete recovery, as a ratio of 0.9 or greater is generally considered necessary for ensuring adequate airway protection.
**Option B:** No fade on Double Burst Tetanic Stimulation is a good indicator of neuromuscular recovery, but it is more specific to the technical assessment of neuromuscular function rather than a direct measure of airway protection.
**Option C:** Return of normal resting minute ventilation, while important, does not directly correlate with the ability to protect the airway from aspiration.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that clinical signs such as **sustained head lift** are practical indicators of recovery from neuromuscular blockade, useful in a clinical setting where more sophisticated monitoring may not be available.

**Correct Answer:** D. Five seconds sustained head lift