Final answer:
For a 170-lb man requiring mechanical ventilation in SIMV mode, initial settings of 8 breaths per minute and a tidal volume of 900ml would likely be appropriate, balancing sufficient ventilation with the patient's comfort and safety.
Step-by-step explanation:
When initiating synchronized intermittent mandatory ventilation (SIMV) mode for mechanical ventilation, it is essential to set both the respiratory rate and tidal volume (VT) appropriately for the specific patient. Given the patient is a 170-lb adult man with neuromuscular disease, we want to achieve adequate alveolar ventilation without causing excessive work of breathing or lung trauma.
Typical starting settings for mechanical ventilation in an adult include a tidal volume of 6-8 ml/kg of ideal body weight and a respiratory rate that ensures adequate ventilation without causing the patient to overbreathe or develop respiratory muscle fatigue. Given this patient's weight (approximately 77 kg), a reasonable starting tidal volume would be around 462-616 ml (77 kg x 6-8 ml/kg), but we may need to adjust this upward considering the patient's disease state to ensure adequate ventilation.
Therefore, of the options given, option a (8/min and 900ml) would likely be most suitable as starting settings. This is a middle of the road approach that balances a moderate respiratory rate with an adequate tidal volume to ensure sufficient ventilation while minimizing the risks of ventilator-induced lung injury. The selected rates and volumes can then be fine-tuned based on arterial blood gas results and other clinical indicators.