This prospective randomized controlled trial was designed to evaluate whether the M1/M3-selective antagonist penehyclidine hydrochloride could more effectively reverse pediatric microcirculatory dysfunction than traditional atropine, particularly when macrohemodynamics appear normalized.

Inclusion Criteria:

1. pediatric patients (aged 28 days to 18 years) admitted with shock who exhibited persistent microcirculatory impairment despite achieving macrohemodynamic stability (normalized mean arterial pressure) through standardized initial resuscitation.
2. presence of at least one of the following clinical markers: (1) capillary refill time (CRT)≥ 3 seconds; (2) serum lactate > 2 mmol/L; (3) cool extremities; or (4) a core-to-peripheral temperature gradient ≥ 2°C.

Exclusion Criteria:

1. refusal of informed consent;
2. congenital cardiovascular malformations or known inherited metabolic disorders;
3. disease severity precluding reliable microcirculatory monitoring;
4. patients undergoing therapeutic hypothermia, which inherently alters vasomotor tone.