Mandibular Advancement vs CPAP for Blood Pressure Reduction in Patients with Obstructive Sleep Apnea

Ou Y-H, Colpani JT, Cheong CS, et al. Am J Cardiol. 2024 (Accepted). [CrossRef]

Background: Hypertension guidelines recommend diagnosis and treatment of obstructive sleep apnea (OSA) in patients with hypertension. The mandibular advancement device (MAD) is an oral appliance therapy for patients who decline or cannot tolerate CPAP.

Objective: We compared the relative effectiveness of MAD versus CPAP in reducing 24-hour ambulatory BP.

Methods: In an investigator-initiated, randomized, non-inferiority trial (pre-specified margin 1.5 mmHg), 321 participants, aged over 40, with hypertension and increased cardiovascular risk were recruited at 3 public hospitals for polysomnography. Of these, 220 participants with moderate-to-severe OSA (apnea–hypopnea index (AHI) ≥15 events/hour) were randomized to either MAD or CPAP (1:1). The primary outcome was the difference between the 24-hour mean arterial BP at baseline and 6 months.

Results: Compared to baseline, the 24-hour mean arterial BP decreased by 2.5 mmHg (P = 0.003) at 6 months in the MAD group, whereas no change was observed in the CPAP group (P = 0.374). The between-group difference was -1.6 mmHg (95% confidence interval: -3.51 to 0.24, non-inferiority P < 0.001). The MAD group demonstrated a larger between-group reduction in all secondary ambulatory BP parameters compared to the CPAP group, with the most pronounced effects observed in the asleep BP parameters. Both the MAD and CPAP improved daytime sleepiness, with the between-group difference similar (P = 0.384). There were no between-group differences in cardiovascular biomarkers.

Conclusion: MAD is non-inferior to CPAP for reducing 24-hour mean arterial BP in participants with hypertension and increased cardiovascular risk.

Telemedicine Critical Care Availability and Outcomes Among Mechanically Ventilated Patients

Graves JM, Krings JG, Buss JL, Kallogjeri D, Ofoma UR. J Crit Care. 2024 Mar 23;82:154782. [CrossRef] [PubMed]

Telemedicine Critical Care (TCC) improves adherence to evidence based protocols associated with improved mortality among patients receiving invasive mechanical ventilation (IMV).  The authors performed a cross-sectional study of 66,522 adults who received IMV for non-postoperative acute respiratory failure at 318 non-federal hospitals in New York, Massachusetts, Maryland, and Florida in 2018. Hospital-level TCC availability was ascertained from the 2018 American Hospital Association Annual Survey. The primary outcome was in-hospital mortality. Secondary outcomes included the composite of tracheostomy or reintubation and duration of IMV. We used two-level hierarchical multivariable regression models to investigate the association between TCC availability and outcomes. 20,270 (30.5%) patients were admitted into 89 TCC-available hospitals. There was no difference between TCC and non-TCC-available hospitals in mortality (odds ratio [OR] 0.94, 99% confidence interval [CI] 0.84–1.05), composite of tracheostomy or reintubation (OR 0.95 [0.82–1.11], or duration of IMV (OR 0.95 [0.83–1.09]). There was no difference in outcomes among the subgroup of patients with acute respiratory distress syndrome. The authors conclude that hospital TCC availability was not associated with improved outcomes among patients receiving IMV. 

Impact of Ambient Ultrafine Particles on Cause-Specific Mortality in Three German Cities

Schwarz M, Schneider A, Cyrys J, Bastian S, Breitner S, Peters A. Am J Respir Crit Care Med. 2023 May 15;207(10):1334-1344. [CrossRef] [PubMed]

Rationale: Exposure to ambient air pollution has been associated with adverse effects on morbidity and mortality. Ambient ultrafine particles (UFPs) result from combustion of combustion of gas, coal or hydrocarbons, biomass burning (i.e. agricultural burning, forest fires and waste disposal), vehicular traffic and industrial emissions, tire wear and tear from car brakes, air traffic, seaport, maritime transportation, restoration and concrete processing, domestic wood stoves, outdoor burning, kitchen, and cigarette smoke. However, the evidence of the impact of UHFs on morbidity and mortality based on epidemiological studies remains scarce and inconsistent. Objectives: The authors examined associations between short-term exposures to UFPs and total particle number concentrations (PNCs; 10–800 nm) and cause-specific mortality in three German cities: Dresden, Leipzig, and Augsburg. Methods: We obtained daily counts of natural, cardiovascular, and respiratory mortality between 2010 and 2017. UFPs and PNCs were measured at six sites, and measurements of fine particulate matter (PM2.5; ⩽2.5 μm in aerodynamic diameter) and nitrogen dioxide were collected from routine monitoring. We applied station-specific confounder-adjusted Poisson regression models. We investigated air pollutant effects at aggregated lags (0–1, 2–4, 5–7, and 0–7 d after UFP exposure) and used a novel multilevel meta-analytical method to pool the results. Additionally, we assessed interdependencies between pollutants using two-pollutant models. Measurements and Main Results: For respiratory mortality, we found a delayed increase in relative risk of 4.46% (95% confidence interval, 1.52 to 7.48%) per 3,223-particles/cm3 increment 5–7 days after UFP exposure. Effects for PNCs showed smaller but comparable estimates consistent with the observation that the smallest UFP fractions showed the largest effects. No clear associations were found for cardiovascular or natural mortality. UFP effects were independent of PM2.5 in two-pollutant models. Conclusions: The authors found delayed effects for respiratory mortality within 1 week after exposure to UFPs and PNCs but no associations for natural or cardiovascular mortality.

Video versus Direct Laryngoscopy for Tracheal Intubation of Critically Ill Adults

M.E. Prekker ME, B.E. Driver BE, S.A. Trent, D. Resnick‑Ault TD, et al. N Engl J Med. 2023 Jun 16. [CrossRef] [PubMed]

Whether video laryngoscopy as compared with direct laryngoscopy increases the likelihood of successful tracheal intubation on the first attempt among critically ill adults is uncertain. In a multicenter, randomized trial conducted at 17 emergency departments and intensive care units (ICUs), critically ill adults undergoing tracheal intubation were randomly assigned to the video-laryngoscope group or the direct-laryngoscope group. The trial was stopped for efficacy at the time of the single preplanned interim analysis. Among 1417 patients who were included in the final analysis (91.5% of whom underwent intubation that was performed by an emergency medicine resident or a critical care fellow), successful intubation on the first attempt occurred in 600 of the 705 patients (85.1%) in the video-laryngoscope group and in 504 of the 712 patients (70.8%) in the direct-laryngoscope group (absolute risk difference, 14.3 percentage points; 95% confidence interval [CI], 9.9 to 18.7; P<0.001). 

Both groups had similar rates of severe complications (peripheral oxygen saturation, <80%, systolic blood pressure <65 mm Hg, new or increased use of vasopressors, cardiac arrest, or death): 21.4% vs 20.9%. The median time of an intubation attempt was 38 seconds and 46 seconds respectively. Safety outcomes, including esophageal intubation, injury to the teeth, and aspiration, were similar in the two groups. 

This trial has several strengths including randomization, an independent observer to prevent observer bias, and low numbers of missing data. However, there were also limitations. The video laryngoscope and the shape of the blade were not standardized, neither were the stylets and bougies utilized. Because 97% of the operators had performed fewer than 250 previous tracheal intubations, the findings may not apply to operators with more experience. 

Additional considerations include the patient’s airway anatomy, positioning, and anticipation of hemoptysis and emesis that will distort the view of the glottis. The COVID-19 pandemic showed us that speed may also be important especially in those very critically ill patients who cannot tolerate more than 20 seconds while attempting to secure the airway. Being familiar with your institution's airway tools is also important because not all hospitals have the same laryngoscopes, stylets or bougies.

Reviewed by Evan D Schmitz MD

Changes in Practice of Controlled Hypothermia after Cardiac Arrest in the Past 20 Years

Nielsen N, Friberg H. Am J Respir Crit Care Med. 2023 Apr 27. doi: 10.1164/rccm.202211-2142CP. Epub ahead of print. [CrossRef] [PubMed]

For 20 years, induced hypothermia and targeted temperaturemanagement have been recommended to mitigate brain injuryand increase survival after cardiac arrest. On the basis of animalresearch and small clinical trials, the International LiaisonCommittee on Resuscitation strongly advocated hypothermia at32–34C for 12–24 hours for comatose patients with out-of-hospital cardiac arrest with initial rhythm of ventricularfibrillation or nonperfusing ventricular tachycardia. Theintervention was implemented worldwide. In the past decade,hypothermia and targeted temperature management have beeninvestigated in larger clinical randomized trials focusing ontarget temperature depth, target temperature duration,prehospital versus in-hospital initiation, nonshockable rhythms,and in-hospital cardiac arrest. Systematic reviews suggest littleor no effect of delivering the intervention on the basis of thesummary of evidence, and the International Liaison Committeeon Resuscitation today recommends only to treat fever and keepbody temperature below 37.5C (weak recommendation,low-certainty evidence). Here we describe the evolution oftemperature management for patients with cardiac arrestduring the past 20 years and how the accrued evidence hasinfluenced not only the recommendations but also the guidelineprocess. We also discuss possible paths forward in this field,bringing up both whether fever management is at allbeneficial for patients with cardiac arrest and which knowledgegaps future clinical trials in temperature management should address. 

There is also an additional review in PulmCCM. Unfortunately, both require subscriptions in order to view the content.