Background: Diagnosis of perioperative anaphylaxis is difficult because of its non-specific and variable signs and symptoms. Therapeutic agents used to treat anaphylaxis and anaesthesiologist responses also vary depending on the case, which might affect outcomes; however, only a few studies have focused on these factors.Methods: This prospective study of perioperative anaphylaxis, a part of the Japanese Epidemiologic Study for Periop-erative Anaphylaxis, investigated the clinical signs, its severity, therapeutic drugs, epinephrine administration, and anaesthesiologist responses in cases of perioperative anaphylaxis to assess trends and variability. Shock index was used to assess severity of cardiovascular collapse.Results: In 43 patients analysed in this study, cardiovascular signs (88.4%) were the most frequent, followed by skin (81.4%) and respiratory signs (60.5%). The presence of signs increased during the clinical course. The median time from the first signs to diagnosis of anaphylaxis was 10 (5.0-17.8) min. The rates of epinephrine use were 30.2% (unused), 48.8% (i.v.), and 20.9% (i.m.). The median time from diagnosis of anaphylaxis to epinephrine administration was 7 (inter-quartile range: 1.5-8.0) min. Antihistamines and corticosteroids were each used in 69.8% of cases. The worst shock index was higher in patients who received i.v. epinephrine (2.77 [0.90] mean [standard deviation]) than in both no epinephrine use cases (1.35 [0.41]) and i.m. epinephrine cases (1.89 [0.77] (P<0.001]).Conclusions: The clinical signs and treatments of perioperative anaphylaxis are variable, and the choice regarding epinephrine administration is based on symptom severity.Clinical trial registration: UMIN000035350.

Optimal positive end-expiratory pressure (PEEP) can induce sustained lung function improvement. This prospective, non-randomized interventional study aimed to investigate the effect of individualized PEEP determined using electrical impedance tomography (EIT) in post-cardiac surgery patients (n = 35). Decremental PEEP trials were performed from 20 to 4 cmH₂O in steps of 2 cmH₂O, guided by EIT. PEEP levels preventing ventilation loss in dependent lung regions (PEEP_ONLINE) were set. Ventilation distributions and oxygenation before the PEEP trial, and 5 min and 1 h after the PEEP_ONLINE setting were examined. Furthermore, we analyzed the saved impedance data offline to determine the PEEP levels that provided the best compromise between overdistended and collapsed lung (PEEP_ODCL). Ventilation distributions of dependent regions increased at 5 min after the PEEP_ONLINE setting compared with those before the PEEP trial (mean ± standard deviation, 41.3 ± 8.5% vs. 49.1 ± 9.3%; p < 0.001), and were maintained at 1 h thereafter (48.7 ± 9.4%, p < 0.001). Oxygenation also showed sustained improvement. Rescue oxygen therapy (high-flow nasal cannula, noninvasive ventilation) after extubation was less frequent in patients with PEEP_ONLINE ≥ PEEP_ODCL than in those with PEEP_ONLINE < PEEP_ODCL (1/19 vs. 6/16; p = 0.018). EIT-guided individualized PEEP stabilized the improvement in ventilation distribution and oxygenation. Individual PEEP varies with EIT measures, and may differentially affect oxygenation after cardiac surgery.

Rationale: Gross Type C congenital esophageal atresia is associated with tracheoesophageal fistula (TEF). Perioperative airway management, including prevention of aspiration of gastric contents, is important. Generally, the TEF is blocked by 1-lung intubation of the dependent lung, or directly by insertion of a balloon catheter. This case report describes successful management of TEF by insertion of a balloon catheter via tracheostoma in an infant with a difficult airway. Patient concerns: A boy with trisomy 18 underwent esophageal banding and gastrostomy for Gross Type C congenital esophageal atresia on postnatal day 3. Tracheostomy was performed on day 49, and definitive surgery for TEF was scheduled on day 83. Diagnoses: The boy was diagnosed with Gross Type C congenital esophageal atresia shortly after birth. Interventions: The patient was re-intubated orotracheally in the NICU. Oral insertion of a 4Fr Fogarty catheter to block the TEF was difficult. Insertion through the available tracheostoma was easier. Outcomes: We confirmed that the catheter could be guided to the TEF entrance using a bronchoscope, and the balloon was expanded to block the TEF. During surgery, there were no problems with airway management. Lessons: In the management of TEF in children after tracheostomy, if oral insertion of the balloon catheter proves difficult, insertion via the tracheostoma may be effective.