Study design, period and study settings
Institutional based cross-sectional study was conducted on pediatric patients that undergone surgery under GA in UOGCSH from February 1 to August 1, 2019.This hospital is located in Amhara region, North Gondar zone, which is about 738km away from Addis Ababa in Northwest of Ethiopia.
All consecutive pediatric patients (birth-12 years) that operated in both emergency and elective conditions with GA at the main and ophthalmic operation theatres during the study period were included.
Variables of the study
The outcome variable was incidence of laryngospasm. The independent variables were socio-demographic factors (age, sex, ASA status), patient factors (current history of URTI, co- morbidities, pre existing airway anomalies, history of exposure to smoke inhalation), anesthetic factors (types of anesthesia, use of oral airway devices, types of induction, induction drugs, maintenance drugs, multiple attempts of airway device insertion, inadequate depth of anesthesia, secretion at oropharynx) and surgical factors (types of surgery, urgency of surgery).
Laryngospasm:glotic closure due to reflex constriction of the laryngeal muscles that produces partial or complete obstruction of the larynx that manifested either alone or in combination of inspiratory stridor, increased respiratory effort, tracheal tug, paradoxical respiratory effort,desaturation and bradycardia.
Signs of inadequate depth anesthesia: when patients were manifested with either movements ,increased breathing, increased heart rate and increased blood pressure in response to stress or painful stimuli.
Multi-attempts of airway device: means if there were ≥2 attempts in securing of the airway
Sample size determination
study done in Jimma University specialized and teaching hospital (2015), Southwest Ethiopia, which reported that the incidence of laryngospasm was 28.3%.By assuming 95% confidence level,5% margin of error and 5 % none response rate, Where; N= Sample size ,P=Percentage ,Q= 1-P,D= Desired degree of precision ,Z= the standard normal value at the level of confidence desired. N= (1.96)2 (0.72) (0.28)/ (.05)2 =309.When 5% of the non- response rate was added, the total number of patients who participated in the study was N=325.
Data management and collection procedures
Training was given for data collectors and supervisors. The training was focused on each item of the study tool, relevance of the study and how to ensure confidentiality of patient’s data.The data collection procedures were including consent from the parents, reviewing of the chart, interviewing of the parents, recording of anesthetic factors, surgical factors, interventions done for cases and laryngospasm incidence at induction, maintenance and emergence phases of GA. During data collection regular supervision and follow up were done for the completeness, accuracy and clarity of data.
Data analysis and interpretation
SPSS version 20 was used for data entry and analysis. Both bivariate and multivariate binary logistic regression analysis were used to identify factors associated with laryngospasm. Variables with a p-value less than <0.2 in the bivariate analysis were fitted into the multivariable logistic regression analysis. Both crude and adjusted odds ratio with the corresponding 95%CI were calculated to show the strength of association. Hosmer and Lemeshow test was used to assess the goodness of fit. In multivariable analysis, variables with a p-value of <0.05 were considered as statistically significant. Categorical variables were analyzed with chi-square test and presented with frequency (percent).Tables and graphs were used for presentation of descriptive data.
Ethical clearance was obtained from ethical review board of school of medicine at University of Gondar. Informed consent was obtained from the parents. Brief explanation for parents was done about the risks and benefits in study participation. Confidentiality and anonymity was ensured.