title: Post-tonsillectomy late haemorrhage: is it a preferably night-time event?
abstract: OBJECTIVE
  To evaluate the relationship between the incidence of late post-tonsillectomy haemorrhage and its prevalence in a definite period of the day.
  
  
  METHODS
  This retrospective study was carried out in the Ear Nose Throat (ENT) Unit of Giannina Gaslini Institute, Genoa, Italy on children operated for adenotonsillectomy (AT) or tonsillectomy (T) between January 2003 and February 2008. We considered in the study all the post-tonsillectomy late haemorrhages irrespective of their severity and for each case we evaluated whether they recurred in the day-time (B) (between 9.00 a.m. and 9.00 p.m.) or in the night-time (A) (between 9.00 p.m. and 9.00 a.m.). Finally we considered the number of haemorrhages per hour in the whole day.
  
  
  RESULTS
  Out of 3306 patients undergoing elective adenotonsillectomy or tonsillectomy, post-operative late haemorrhage occurred in 59 (1.78%). We noted that 42 episodes (71.2%) occurred in the night-time and 17 (28.8%) in the day-time. The average time from the operation was 8.4 days. A statistically significant difference (p=0.002) was found when comparing the frequencies of night-time and day-time haemorrhages. We did not observe any significant difference in the distribution per hour of the haemorrhages.
  
  
  CONCLUSIONS
  The incidence of post-tonsillectomy late haemorrhage in our study population was 1.78%. A statistically significant difference was found between night-time and day-time haemorrhages. Even though no significant distribution of haemorrhages per hour was observed, we underline that we recorded 32 (54.2%) events in 2 periods of the day: from 10 p.m. to 1 a.m. and from 6 to 9 a.m.
authors.affiliation: Department of Otolaryngology, Istituto G. Gaslini Largo G. Gaslini 5, Genova, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: D'Agostino
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Tarantino
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Calevo
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D019106:Postoperative Hemorrhage / Q000453:epidemiology*; D015995:Prevalence; D012189:Retrospective Studies; D014068:Tonsillectomy