Aaron M. Joffe

Test ventilating prior to administration of neuromuscular blockade (NMB) in order to avoid a cannot intubate-cannot ventilate situation is a classic anesthesia teaching. The primary aim of our study was to show that facemask ventilation (FMV) after NMB was not inferior to FMV prior to NMB with respect to exhaled gas volumes before and after their administration. This study was approved by the University of Washington Human Subjects Division (Seattle, Washington, USA). Written informed consent was obtained from all patients. Measurements of tidal volume (Vte) as well as other respiratory parameters during FMV were made for 60 s after induction of anesthesia and again after NMB. Difficult, impossible, inadequate, and dead-space only mask ventilation was graded using published definitions. Difficult intubation was defined as >2 attempts at intubation. The primary outcome was non-inferiority in Vte during both study periods defined as a mean difference of <50 mL. Multivariate analysis was performed to assess for interaction between operator experience, patient risk factors for difficult mask ventilation, exhaled volumes, and use of airway adjuncts. Two-hundred and ten patients were studied. Overall, FMV improved after NMBD. The mean (SD) Vte in mL/breath increased from 399 (169) to 428 (166) (mean dif. 30 mL, p = 0.001) and the minute ventilation in L/min from 5.6 (2.5) to 6.3 (2.5) (mean dif. 0.6, p < 0.001). No patient who was difficult to ventilate after induction became impossible after NMB. In patients at risk for or judged to be a difficult FMV by clinical grading scales, tidal volumes improved after administration of NMBDs. None of these patients exhibited a decline in ventilation or became impossible to ventilate after NMBDs. Several limitations are noted, including the use of hand-delivered breaths and inability to account for time-related changes in ventilation conditions independent of NMBDs. We conclude that FMV is no worse after NMB than before and is likely to improve airway conditions. ClinicalTrials.gov Identifier: NCT02237443 . Registered August 28, 2014

The occurrence of hypovolemia in the setting of cerebral vasospasm reportedly increases the risk for delayed ischemic neurologic deficits. Few studies have objectively assessed blood volume (BV) in response to fluid administration targeting normovolemia (NV) or hypervolemia (HV) and none have done so with crystalloids alone. The primary purpose was to evaluate the BV of patients with SAH receiving crystalloid fluid administration targeting NV or HV. The University of Washington IRB approved the study. Prospectively collected data was obtained from patients enrolled in a clinical trial and a concurrent group of patients who received IV fluids during the ICU stay. We defined a normovolemia (NV) and hypervolemia (HV) group based on the cumulative amount of IV fluid administered in mL/kg from ICU admission to day 5; ≥30–60 mL/kg/day (NV) and ≥60 mL/kg/day (HV), respectively. In a subgroup of patients, BV was measured on day 5 post ictus using iodinated ¹³¹I-labeled albumin injection and the BVA-100 (Daxor Corp, New York, NY). Differences between the NV and HV groups were compared using Student’s t-test with assumption for unequal variance. Twenty patients in the NV and 19 in the HV groups were included. The HV group received more fluid and had a higher fluid balance than the NV group. The subgroup of patients in whom BV was measured on day 5 (n = 19) was not different from the remainder of the cohort with respect to the total amount of administered fluid and net cumulative fluid balance by day 5. BV was not different between the two groups and varied widely. Routinely targeting prophylactic HV using crystalloids does not result in a higher circulating BV compared to targeting NV, but the possibility of clinically unrecognized hypovolemia remains.

Placement of advanced airways has been associated with worsened neurologic outcome in survivors of out-of-hospital cardiac arrest. These findings have been attributed to factors such as inexperienced operators, prolonged intubation times and other airway related complications. As an initial step to examine outcomes of advanced airway placement during in-hospital cardiac arrest (IHCA), where immediate assistance and experienced operators are continuously available, we examined whether cardiopulmonary resuscitation efforts affect intubation difficulty. Additionally, we examined whether or not the use of videolaryngoscopy increases the odds of first attempt intubation success compared with traditional direct laryngoscopy.