Cost of Hospitalization in Children Who Develop Perioperative Respiratory Event
Condition: Hospitalization; Cost of Illness
Study type: Observational

Summary: 
      Mortality related with cardiac arrest in anesthetized children has diminished over several
      decades from 2.9 per 10000 anesthesias in 1961 to 0.21 per 10000 anesthesias in 2007.(1) Even
      though the mortality rate related to pediatric anesthesia is much lower than before,
      respiratory complications related with peri-operative cardiac arrest are as high as 27%
      according to the Pediatric Peri-operative Cardiac Arrest (POCA) Registry.(2).Therefore,
      peri-operative respiratory event (PRE) in pediatric anesthesia such as laryngospasm, stridor,
      bronchospasm, desaturation and reintubation are crucial.

      Stridor and reintubation occur after the children are extubated, mostly in the PACU period.
      Laryngospasm, stridor, bronchospasm and wheezing can lead to desaturation and the need for
      reintubation. Those PRE, especially peri-operative desaturation, can prolong PACU stay
      especially if PRE develops in the PACU.(8,9) PRE occurring during the intraoperative period
      can also prolong PACU stay if children are observed at PACU and not transferred directly to
      the intensive care unit (ICU). Some children require oxygen therapy in the PACU and continue
      at the ward. Some need endotracheal tube intubation with spontaneous breathing or are placed
      on mechanical ventilator. Thai AIMS (10) reported that desaturation at PACU was associated
      with re-intubation, prolonged mechanical ventilation and unplanned ICU admission. Oxygen
      supplement need, prolonged mechanical ventilation or unplanned ICU admission can produce
      extra days of hospitalization or increase the cost of hospitalization from extra-cost payment
      eg; oxygen therapy, mechanical ventilator, cost of ICU stayed.

      Furthermore, the short-term sequelae regarding cost of hospitalization of children who
      develop PRE has never been evaluated or compared with the cost in children who do not develop
      PRE. Higher cost of hospitalization after occurrence of PRE in anesthetized children will
      have an impact to the hospital policy maker. Minimizing PRE can save on the cost of hospital
      care to the public hospital or other health sectors.

      Therefore, we would like to compare days of hospitalization and cost differences of
      hospitalization between children who develop PRE and children who do not develop PRE at a
      tertiary care hospital in southern Thailand
    

Detailed description: 
      1. Study design A prospective observational study

        2. Study setting Children aged < 15 years who received general anesthesia in
           Songklanagarind Hospital between November 2012 and December 2013

        3. Study samples Inclusion criteria Children aged < 15 years who received general
           anesthesia and developed PRE or who had no PRE in Songklanagarind Hospital between
           November 2012 and December 2013.

      Exclusion criteria

        1. ASA classification 4 or 5

        2. Preoperative SpO2 < 95% at room air

        3. Required preoperative endotracheal tube intubation (ETT) or mechanical ventilation

        4. Had congenital cyanotic heart disease

      4. Study size Sample size calculation The sample size calculation is based on a comparison
      between groups of the outcomes of days and cost of hospitalization between PRE and non-PRE
      group 5. Sampling technique Purposive identification of children aged < 15 years old who
      receive general anesthesia and develop Peri-operative respiratory event (PRE) between
      November 2012 and December 2013.was selected for PRE or exposed group. Peri-operative
      respiratory event (PRE) is defined as any respiratory event eg; laryngospasm, stridor,
      wheezing, bronchospasm, reintubation, with or without desaturation, which occurs during the
      intraoperative or PACU period. For non-PRE or non-exposed group, the matching with exposed
      group on the same demographic data will be performed as below.

        -  Matching on the same year of anesthesia

        -  Matching on the same type of surgery

        -  Matching on the same type of anesthesia After matching the same type of surgery and
           anesthesia with exposed group, non-exposed group will be randomly selected by simple
           random sampling technique if there are more than 4 suitable non-exposed subjects
           available. The ratio of exposed group and non-exposed group will be 1 to 4.

           6 Outcome variables The outcome variables are divided into days of hospitalization and
           cost of hospitalization.

      Days of hospitalization Days of hospitalization is the days that the children stay in the
      hospital until discharge home Days of hospitalization will be compared between PRE group and
      non-PRE group Cost of hospitalization Cost of hospitalization is the total cost of
      hospitalization including direct and indirect costs (25,26)

        -  Direct cost are the hospital charge multiplied by cost-to-charge ratio (CCR)

        -  Hospital charges are all the medical cost including medication, procedure related with
           anesthesia or surgery, material cost related with procedure, extra-cost from
           complication postoperatively: ICU stay, cost of ventilator or oxygen therapy,
           accommodation and meals charge

        -  Indirect costs are the cost including transportation (T), productivity loss eg; cost of
           work leave (L)/day Therefore, cost of hospitalization

             -  (hospital charge* CCR) + T + (L* days of hospitalization) According to the payer
                perspective, the CCR is equal to 1 Cost of hospitalization will be compared between
                PRE group and non-PRE group. The total cost of hospitalization from each group is a
                transfer payment not a real payment because 80% of the hospital charge is
                subsidized with the insurance coverage by government eg; universal coverage (UC),
                social security, government corporation or Comptroller General Department, which
                cannot reflect the societal cost. Moreover, we do not consider the cost of
                hospitalization following the disease related groups (DRG) payment in this project.

                7. Independent variables Patient related factors

                  1. Age

                  2. Sex

                  3. Weight

                  4. Height

                  5. ASA classification

                  6. History of upper respiratory tract infection

                  7. History of parental smoking

                  8. History of snoring: yes vs no

                  9. Postoperative complications - Related to surgery

                     - Related to anesthesia

                       -  Related to anesthesia and surgery Anesthetic related factors

                1. Type of surgery 2. Choice of general anesthesia 3. Technique of general
                anesthesia 4. Induction agent 5. Intubation agent 6. Inhalation agent used 7. Gas
                mixed with oxygen used 8. Type of narcotic 9. Duration of anesthesia 10. Period of
                PACU stayed 11. Developed any respiratory events : Yes vs no 12. Peri-operative
                respiratory event 13. The period of respiratory events developed : intraoperative
                vs PACU 14. The lowest oxygen saturation of respiratory events developed 15.
                Postoperative on oxygen therapy 16. Postoperative on mechanical ventilation

                8. Data processing and analysis Descriptive component Analysis will be performed
                with the R program version 2.14.1. Descriptive statistics will be computed for all
                variables and include frequency, proportion, mean + SD and median (range).
                Predictor variables will be categorical data either originally or if continuous,
                categorized by selected suitable cut points.

      Analytic component The days of hospitalization will be compared between PRE and non-PRE group
      using simple linear regression model. The other explanatory variables that may be related to
      prolonged hospitalization will be analyzed using multiple linear regression models if showing
      some evidence of differing across outcome categories in univariate analysis (p ≤ 0.2). The
      magnitudes and precision of associations will be indicated by adjusted coefficient and their
      95% confidence intervals.

      Total cost of hospitalization will be compared between PRE and non-PRE group using simple
      linear regression model. Cost of hospitalization will be calculated both using CCR 0.4
      (hospital perspective) and 1 (payer perspective). The other explanatory variables that may be
      related to higher cost of hospitalization will be analyzed using multiple linear regression
      models if showing some evidence of differing across outcome categories in univariate analysis
      (p ≤ 0.2). The magnitudes and precision of associations will be indicated by adjusted
      coefficient and their 95% confidence intervals.

      For both days and cost of hospitalization, if the distribution is not suitable for linear
      regression or the assumption of linear regression is not met, the other alternative analysis
      methods may be preferred eg; logarithmic transform, quantile regression or Cox regression.

      In multivariate modeling techniques, association with outcome will be considered significant
      if the likelihood ratio p-values are ≤ 0.05.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Children aged < 15 years who received general anesthesia in Songklanagarind Hospital
        between November 2012 and December 2013
      
Keywords: pediatric anesthesia; perioperative respiratory events; days of hospitalization; cost of hospitalization