Autonomic Modulation After Spinal Anesthesia With Depth of Anesthesia and Vital Signs.
Condition: Participants Scheduled for Surgery Under Spinal Anesthesia Without Impairment of Renal, Hepatic, Cardiac or Respiratory Function
Study type: Observational

Summary: 
      Spinal anaesthesia has the advantage that produced nerve block by the injection of local
      anaesthetic into cerebrospinal fluid (CSF). However, the greatest challenge in spinal
      anaesthesia is to control the spread of local anaesthetic through the CSF to provide a block
      which is adequate for the proposed surgery without unnecessary extensive spread, and
      increased risk of complications.
    

Detailed description: 
      The activity of the autonomic nervous system is of fundamental importance in the regulation
      of vital bodily functions. Unbalance of autonomic nerve system results in considerably
      disordered vital function. Clinically, this is of great significance, because if an
      anesthetic agent produces cause the sympathetic system to block, the effects can be serious
      in individual cases, particularly on the cardiovascular system. If complications are to be
      avoided, it is essential to assess the degree of block correctly. Clinical monitoring has a
      variety of applications, a particularly useful one being measurement of the sympathetic
      system during regional anesthesia, for which quantification of the blocking effect is a
      clinical necessity and the degree of block needs to be ascertained without delay. The
      autonomic nervous system (ANS) plays an important role in the regulation of hemodynamics
      during anesthesia. Analysis of beat-to-beat fluctuations of heart rate and blood pressure is
      a promising new approach to the clinical diagnosis and management of alterations in
      cardiovascular regulation. Continuous Wavelet Transform (CWT), which could overcome the
      limitation of the steady-state assumption in the classical spectral analysis, is believed as
      a reliable and robust method to access cardiorespiratory dynamics of the ANS and the
      investigators will applied during spinal anesthesia to evaluate the detail changes.
    

Intervention name(s): observation study about the autonomic response after spinal anesthesia
Intervention type(s): Other
Intervention description(s): ECG waveforms were continuously recorded using a multichannel polygraphic system (Embla N7000, Natus, Pleasanton, CA). The data were saved at a rate of 1024 Hz directly to a memory card within the device for offline analysis of heart rate variability (HRV) and PPG. All data included in the analysis were obtained from continuous artifact-free ECG recordings for analysis of the immediate effects of spinal anesthesia.
Intervention MeSH terms: Anesthetics
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        The investigators conducted a prospective observational study on patients who were
        scheduled to undergo elective surgery and spinal anesthesia. The investigators excluded
        patients who had recently been treated with a sedative, beta-blocker, parasympatholytic, or
        opioid agent, patients who had undergone emergency surgery, those with hypovolemia and
        hypothermia, arrhythmia, diabetes, or impairment of renal, hepatic, coagulation, cardiac,
        or respiratory function