Final answer:
Increased respiratory rate is a sign of a cholinergic crisis in a client with myasthenia gravis. This crisis is characterized by overstimulation at the neuromuscular junction, leading to symptoms such as muscle twitching and excessive secretions, which can affect breathing.
Step-by-step explanation:
The sign that indicates a cholinergic crisis is occurring in a client with myasthenia gravis is an increased respiratory rate. During a cholinergic crisis, due to an excess of acetylcholine at the neuromuscular junction, the client may experience symptoms like muscle twitching/fasciculations, miosis (pinpoint pupils), and copious secretions. This overstimulation can lead to respiratory muscle paralysis, which can increase the respiratory rate as the body attempts to compensate for impaired gas exchange.
In the context of the question, bradycardia, hypertension, and decreased salivation are less indicative of a cholinergic crisis. These symptoms could be associated with other conditions, but during a cholinergic crisis, an increase in salivation rather than a decrease would be expected due to overstimulation of muscarinic receptors.