Ultrasound Assessment of the Subclavian Vein for Predicting Hypotension in Children After Anaesthesia Induction
Condition: Anesthesia Complication; Hypotension on Induction; Hypovolemia
MeSH terms: Hypotension; Hypovolemia
Study type: Observational

Summary: 
      Intra operative hypotension is a risk factor in pediatric anesthesia (McCann ME et al.Pediatr
      Anesth 2014; 24: 68-73). In summary, the study aims at examine if ultrasound assessment of
      the diameter and collapsibility index of the subclavian vein is correlated to fasting time
      and if they are correlated to the degree of hypotension seen post anesthesia induction in
      children undergoing general anesthesia.
    

Detailed description: 
      Background: Intra operative hypotension is a risk factor in pediatric anesthesia (McCann ME
      et al.Pediatr Anesth 2014; 24: 68-73). Bedside ultrasonic assessment of the inferior vena
      cava (IVC) and IVC collapsibility index (IVCCI) has been shown to indicate fluid status in
      both adults and children breathing spontaneously (Marcell Szabó et al. BMC Anesthesiol. 2019;
      19: 139., Lei Chen et al.Acad Emerg Med. 2007 Oct;14(10):841-5.). Ultrasound assessment of
      subclavian vein/axillary vein collapsibility has recently been shown to predict hypotension
      after induction of general anesthesia in adults (Min Hee Choi et al. Eur J Anaesthesiol 2020;
      37:474-481). The inverstigators hypothesized that subclavian vein (SCV) collapsibility index
      is correlated to fasting time and potentially can be used to predict post induction
      hypotension in children.

      Objective: To examine if ultrasound assessment of the diameter and collapsibility index of
      the SCV is correlated to fasting time and can be a predictor of post induction hypotension in
      children undergoing general anesthesia.

      Design and setting: Prospective observational study in a day case surgical unit in a tertiary
      university hospital.

      Patients: Children aged 0-18 years ASA 1-2 undergoing anesthesia for day case surgery after
      written and informed consent from parents is obtained according to local ethical permit.
      Exclusion criteria: ongoing medication for hypertension.

      Measurements and results: Based on previous studies (Min Hee Choi et al. Eur J Anaesthesiol
      2020; 37:474-481), a sample size of approximately 80 subjects will be needed. Data on fasting
      time will be collected after informed and written consent has been obtained. Before the
      induction of anesthesia, the patients will be breathing spontaneously in a supine position.
      Noninvasive blood pressure will be recorded. An ultrasound examination of SCV will then be
      performed on cross section of the vessel both in 2D and M-mode and the minimum and maximum
      diameters of the SCV will be recorded. Collapsibility index will then be calculated from
      these data as previously described (Min Hee Choi et al. Eur J Anaesthesiology 2020;
      37:474-481). After this, the subjects will undergo anesthesia under which blood pressure will
      be recorded according to departmental standard as usual. SCV collapsibility index will then
      be investigated for potential significant correlation with fasting time and percentage
      decrease in blood pressure from baseline after anesthesia induction and during the surgical
      preparation phase, before start of surgery.
    

Intervention name(s): Ultrasound assessment of SCV
Intervention type(s): Other
Intervention description(s): An ultrasound examination of the SCV will be performed before anesthesia induction. Apart from this, the protocol does not differ at all from the ordinary fashion
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Children aged 0-18 years ASA 1-2 undergoing anesthesia for day case surgery