Asthma is characterised by inflammation and respiratory symptoms. Current asthma treatment is based on severity of asthma symptoms only. Exhaled nitric oxide fraction (FeNO) is not recommended by the Global Initiative for Asthma guidelines. The aim was to compare the usefulness of a FeNO guided versus symptom-based treatment in achieving improved asthma control assessed by airway hyperresponsiveness (AHR).80 asthmatic patients were included in a double-blinded, parallel, randomised controlled trial with follow-up visits after 8, 24 and 36 weeks. Treatment was tailored using either a FeNO or Asthma Control Questionnaire (ACQ) based algorithm. Inclusion criteria were asthma symptoms and a provocative dose causing a 15% fall in forced expiratory volume in 1 s <635 mg mannitol. At each visit AHR, FeNO, ACQ and blood tests were performed.No differences between the two groups were found at inclusion. AHR from 8 to 24 weeks was improved in the FeNO group compared to the ACQ group (response dose ratio (RDR) geometric mean (95% CI): 0.02 (0.01–0.04) versus 0.05 (0.03–0.07), respectively, p=0.015). AHR to mannitol at 36 weeks showed no differences between the two groups (mean difference RDR (95% CI): −0.02 (−0.05–0.02), p=0.3). Total doses of inhaled steroid and number of exacerbations were similar (p>0.05).When using FeNO as a treatment management tool, lowering of airway responsiveness occurred earlier than using ACQ. However, airway responsiveness and asthma control after 9 months were similar.

ObjectiveTo describe the association between intraoperative tissue oxygenation and postoperative troponin elevation in patients undergoing major spine surgery. We hypothesised that a decrease in intraoperative skeletal muscle tissue oxygenation (SmO2) was associated with the peak postoperative cardiac troponin value.DesignThis is a prospective cohort study.SettingSingle-centre, University of California San Francisco Medical Center.ParticipantsSeventy adult patients undergoing major elective spine surgery.Primary and secondary outcome measuresHigh-sensitivity troponin T (hsTnT) was measured in plasma preoperatively and on the first and second day after surgery to assess the primary outcome of peak postoperative hsTnT. Secondary outcomes included MINS and intensive care unit (ICU) admission within 30 days. Skeletal cerebral tissue oxygenation and SmO2 was measured continuously with near-infrared spectroscopy during surgery. The primary exposure variable was time-weighted area under the curve (TW AUC) for SmO2.ResultsMean age was 65 (33–85) years and 59% were female. No significant association was found between TW AUC for SmO2 and peak hsTnT (Spearman’s correlation, rs=0.17, p=0.16). A total of 28 (40%) patients had MINS. ICU admission occurred in 14 (40%) in lower vs 25 (71%) in upper half of patients based on TW AUC for SmO2, p=0.008.ConclusionsDecrease in SmO2 was not a statistically significant predictor for peak troponin value following major spine surgery but is a potential predictor for other postoperative complications.Trial registration numberNCT03518372.