Blood gas phenotyping and tracheal intubation timing in adult in-hospital cardiac arrest: a retrospective cohort study

To investigate whether the optimal time to tracheal intubation (TTI) during cardiopulmonary resuscitation would differ by different blood gas phenotypes. Adult patients experiencing in-hospital cardiac arrest (IHCA) from 2006 to 2015 were retrospectively screened. Early intra-arrest blood gas analysis, performed within 10 min of resuscitation, was used to define different phenotypes. In total, 567 patients were included. Non-severe acidosis (pH≧7.15) was associated with favourable neurological outcome (odds ratio [OR]: 4.60, 95% confidence interval [CI] 1.63–12.95; p value = 0.004) and survival (OR: 3.25, 95% CI 1.72–6.15; p value < 0.001) in the multivariable logistic regression analyses. In the interaction analysis, normal blood gas phenotype (pH: 7.35–7.45, PCO2: 35–45 mm Hg, HCO3− level: 22–26 mmol/L) × TTI ≦ 6.3 min (OR: 20.40, 95% CI 2.53–164.75; p value = 0.005) and non-severe acidosis × TTI ≦ 6.3 min (OR: 3.35, 95% CI 1.00–11.23; p value = 0.05) were associated with neurological recovery while metabolic acidosis × TTI ≦ 5.7 min (OR: 3.63, 95% CI 1.36–9.67; p value = 0.01) and hypercapnic acidosis × TTI ≦ 10.4 min (OR: 2.27, 95% CI 1.20–4.28; p value = 0.01) were associated with survival. Intra-arrest blood gas analysis may help guide TTI during for patients with IHCA.

Management of hypercapnia in critically ill mechanically ventilated patients—A narrative review of literature

The use of lower tidal volume ventilation was shown to improve survival in mechanically ventilated patients with acute lung injury. In some patients this strategy may cause hypercapnic acidosis. A significant body of recent clinical data suggest that hypercapnic acidosis is associated with adverse clinical outcomes including increased hospital mortality. We aimed to review the available treatment options that may be used to manage acute hypercapnic acidosis that may be seen with low tidal volume ventilation. The databases of MEDLINE and EMBASE were searched. Studies including animals or tissues were excluded. We also searched bibliographic references of relevant studies, irrespective of study design with the intention of finding relevant studies to be included in this review. The possible options to treat hypercapnia included optimising the use of low tidal volume mechanical ventilation to enhance carbon dioxide elimination. These include techniques to reduce dead space ventilation, and physiological dead space, use of buffers, airway pressure release ventilation and prone positon ventilation. In patients where hypercapnic acidosis could not be managed with lung protective mechanical ventilation, extracorporeal techniques may be used. Newer, minimally invasive low volume venovenous extracorporeal devices are currently being investigated for managing hypercapnia associated with low and ultra-low volume mechanical ventilation.

Oxygen alert wristbands (OxyBand) and controlled oxygen: a pilot study

Despite the introduction of Oxygen Alert Cards, guidelines and audits, oxygen therapy remains overused in NHS practice, and this may lead to iatrogenic mortality. This pilot study aimed to examine the use of Oxygen Alert Wristbands (OxyBand) designed to alert health professionals who are delivering oxygen to patients to ensure that the oxygen is administered and titrated safely to the appropriate target saturations. Patients at risk of hypercapnic acidosis were asked to wear OxyBands while presenting to paramedics and health professionals in hospitals. Inappropriate prescription of oxygen reduced significantly after the OxyBands were used. A questionnaire-based assessment showed that the clinicians involved had a good understanding of the risks of uncontrolled oxygen. Forty-two patients found the wrist band comfortable to wear, and only two did not. OxyBands may have the potential to improve patient safety over Oxygen Alert Cards.