Which vital sign change would prompt immediate intervention during newborn resuscitation?

During newborn resuscitation, a heart rate below 100 beats per minute is a critical indicator that requires immediate intervention. This is because a heart rate below this threshold can signify compromised cardiac output and inadequate perfusion, which can lead to serious complications if not addressed promptly. In the context of resuscitation, ensuring that the heart rate is above 100 is vital to establish a stable and effective circulatory response.

The other vital sign changes indicated in the options, while potentially concerning, do not necessitate the same level of urgency in the context of initial resuscitation procedures. For instance, a respiratory rate above 60 breaths per minute may indicate mild respiratory distress but is typically not an immediate threat unless accompanied by additional signs of respiratory failure. A temperature below 36.0°C is significant for potential hypothermia, but this can often be managed after the stabilization of airways and circulation. Oxygen saturation above 95% is generally considered adequate, and while monitoring is essential, it does not indicate a critical emergency that requires immediate action during the initial phases of resuscitation.