
    In a hospital's patient monitoring system, given a series of patient-risk assessment pairs where each pair contains a patient ID and their calculated risk score, identify the patient ID that corresponds to the most critical risk score (lowest numerical value). The risk scores are derived from real-time vital signs monitoring, where lower scores indicate higher medical urgency.
    

    
from operator import itemgetter

def index_minimum(test_list):
    """
    In a hospital's patient monitoring system, given a series of patient-risk assessment pairs where each pair contains a patient ID and their calculated risk score, identify the patient ID that corresponds to the most critical risk score (lowest numerical value). The risk scores are derived from real-time vital signs monitoring, where lower scores indicate higher medical urgency.
    

    """
from operator import itemgetter

def index_minimum(test_list):
    """
    In a hospital's patient monitoring system, given a series of patient-risk assessment pairs where each pair contains a patient ID and their calculated risk score, identify the patient ID that corresponds to the most critical risk score (lowest numerical value). The risk scores are derived from real-time vital signs monitoring, where lower scores indicate higher medical urgency.
    

    """
    res = min(test_list, key=itemgetter(1))[0]
    return res