Respiratory Care

We previously implemented a policy that enabled respiratory therapists to reject orders for nebulized 3% hypertonic saline and/or N-acetylcysteine (HTS/NAC) that did not conform to the American Association for Respiratory Care (AARC) Clinical Practice Guideline. Outcomes of adhering to this more conservative approach are not well studied. We sought to determine if an approach conforming to guidelines is noninferior to a previously practiced more liberal approach.

We performed a retrospective analysis of 2,272 subjects receiving mechanical ventilation ≥48 h within 5 adult ICUs between June 2020 and August 2023. The primary outcome was ventilator-free days at day 28 (VFD28). Secondary outcomes included ventilator days, ICU days, hospital stay, re-intubation rates, and mortality. Analysis was stratified by before and after policy implementation (see intervention) and by receiving HTS/NAC or not (ϕHTS/NAC). The latter was examined before and after propensity matching. The Δ for noninferiority was −0.5 days for VFD28 and +0.5 days for other continuous variables. As outcomes were not normally distributed, we analyzed them using Mann–Whitney U statistics.

Two thousand two hundred seventy-two subjects were evaluated. The mean age was 58.70 + 16.13 years and 929 (40.9%) subjects were women. HTS/NAC administration was reduced after policy implementation (40.2% before policy and 8.9% after policy; a reduction of 77.9%). The post-policy group and ϕHTS/NAC before and after propensity matching groups were all noninferior to the comparators. Subjects had significantly more VFD28 in the post-policy group, median (IQR), post 21 (0–25), pre: 20 (0–24), P = .02; and in the ϕHTS/NAC group, before matching ϕHTS/NAC: 21 (0–25), HTS/NAC: 18 (0–23), P < .001 and after propensity matching ϕHTS/NAC: 21 (0–25), HTS/NAC; 18 (0–23), P < .001.

Restricting practice to conform to the AARC Clinical Practice Guideline was noninferior to more liberal use. The use of HTS/NAC in mechanically ventilated subjects does not appear efficacious and is both costly and time-consuming.

Respiratory viruses such as influenza and human rhinoviruses are temperature sensitive. Rhinothermy delivers heated, humidified air to the upper airways via the nares, and by possibly inhibiting viral replication, it is proposed as a potential therapy to attenuate the severity and duration of common cold or influenza symptoms. The effect of rhinothermy on nasopharyngeal air space temperature is uncertain. The objective of this study was to investigate the effect of rhinothermy delivering 100% humidified air at 41°C on nasopharyngeal air space temperature. The hypothesis was that the mean nasopharyngeal air space temperature while nose breathing would be within 1.5°C of the device’s set dew point temperature of 41°C.

In this single-center nonblind nonrandomized parallel arm interventional study, nasopharyngeal air space temperature was continuously measured during delivery of 100% humidified air via a nasal high-flow device at 41°C and 30–35 L/min (rhinothermy [rNHF]) (n = 6), and at 31°C and 10 L/min (‘sham’ rhinothermy) (n = 6). The primary outcome measure was mean nasopharyngeal air space temperature during delivery of rNHF while nose breathing. Change in nasopharyngeal air space temperature during nose breathing and mouth breathing was compared for both interventions.

Twelve participants age 18–75 years were recruited. The mean (SD) nasopharyngeal air space temperature during rNHF at 41°C while nose breathing was 37.9°C (1.22) and with sham rhinothermy at 31°C was 36.8°C (0.18). There was no significant difference in nasopharyngeal air space temperature between nose and mouth breathing for both interventions combined (difference [95% CI] −0.1°C [−0.59 to 0.36], P = .60).

The mean nasopharyngeal air space temperature during rNHF while nose breathing was not within 1.5°C of the device’s set dew point temperature of 41°C. rNHF temperatures may need to be set considerably higher than the target nasopharyngeal air space temperature when investigating the effect of rhinothermy on symptom severity or duration of respiratory infections caused by viruses with temperature-dependent replication.

Unreported and untreated exacerbations of COPD have significant negative impacts on health status, disease progression, rate of hospitalization, and readmission. The present study investigated whether a COPD exacerbation prediction algorithm embedded into a telemonitoring system can reduce the number of hospitalizations and improve health-related quality of life (HRQOL) compared with telemonitoring alone.

A total of 137 participants were enrolled in this single-blinded randomized controlled trial. Patients were eligible for inclusion if they had a COPD diagnosis, were adults, had fixed residence in Aalborg Municipality in Denmark, and already used an existing telemonitoring system. The primary outcome was the between-group difference in the number of acute hospitalizations per subject after 6 months of follow-up. Secondary outcomes included the difference in all-cause hospitalization, HRQOL measured by 12-item Short Form Health Survey (version 2) and EuroQol-5 Dimension Questionnaire (EQ-5D-5L), and mortality after 6 months. Data were analyzed according to the intention-to-treat principle.

The adjusted incidence rate ratio (IRR) of acute hospitalizations per subject was 1.30 (95% CI 0.50–3.38). The odds ratio (OR) for the hospitalization proportion was 2.10 (95% CI: 0.72–6.09). The adjusted IRR for the number of all-cause hospitalizations were 1.25 (95% CI: 0.51–3.07), whereas the OR for an all-cause hospitalization proportion was 1.92 (95% CI: 0.70–5.26). The adjusted OR for mortality was 0.46 (95% CI: 0.11–1.94). The adjusted mean difference in the physical component score and mental component score was 0.77 (95% CI: −1.72 to 3.47) and 0.91 (95% CI: −2.63 to 4.72), respectively, and −0.05 (95% CI: −0.14 to 0.03) for the EQ-5D index score. All results were nonstatistically significant.

No definitive conclusions could be drawn regarding the effect on hospitalizations and HRQOL when implementing a COPD prediction algorithm in addition to telemonitoring.

Endotracheal tube (ETT) cuffs prevent over-the-cuff secretions from flowing into the lower airways. However, they may not completely prevent fluid leakage around ETTs. To validate a cuff design with high sealing capacity, we compared ETTs with varying cuff materials and structural properties.

We used 7 ETTs with different cuff materials (polyvinyl chloride [PVC], polyurethane [PU]), shapes (conical, tapered, or cylindrical), wall thickness, and cuff sizes (contact area with the trachea). Wall thickness was measured after cutting the cuff using a micrometer. The contact area was calculated based on the long diameter of the cuff when expanded within a clear acrylic tube. The sealing capacity was defined as the time taken for 10 mL of distilled water to leak past the cuff. The sealing capacities of the cuffs were compared by inserting them into the simulated trachea (silicone corrugated tube).

The wall thicknesses were 29–29.3 µm for PU and 45.6–285 µm for PVC cuffs. The contact areas with the trachea were 18.7–27.1 and 12.5–22.3 cm for PU and PVC cuffs, respectively. The mean (SD) sealing capacities were 2,381 (484), 437 (177), 56 (12), and 24 (4) s for the cylindrical PU, conical PU, tapered PVC, and conical PVC cuffs, respectively. For the 3 cylindrical PVC cuffs (A, B, and C, respectively), the mean (SD) sealing capacities were 53 (11), 15 (2), and 9 (2) s.

The PU cuff had a higher sealing capacity than the PVC cuff, and the cylindrical cuff had a higher sealing capacity than the conical cuff. For the PVC cuff, thinner materials had higher sealing capacities. Furthermore, the contact area between the cuff and model trachea significantly affected the sealing capacity.

Postoperative patients receiving opioids are at risk for morbidity and mortality caused by opioid-induced respiratory depression (OIRD). Guidelines advocate electronic monitoring for OIRD during postoperative hospitalization, but the utility of home monitoring following ambulatory surgery has not been assessed. We describe the utilization of capnography and pulse oximetry in an ambulatory orthopedic cohort to determine subject/home caregiver acceptance and utility of continuous monitors at home. The specific aims of this initiative were to (1) determine the subject/home caregiver acceptance of home monitoring to detect OIRD in patients after hospital discharge following orthopedic surgery, (2) determine the rate of OIRD and associated morbidity after hospital discharge following orthopedic surgery, and (3) determine patient understanding of the risk of OIRD.

This prospective, subject/home caregiver acceptance quality improvement initiative was conducted from September 28, 2019, to October 31, 2020. Ambulatory subjects undergoing orthopedic surgical procedures had cardiorespiratory data monitored with a commercially available device at home for 4 days while napping/sleeping. Recorded data were analyzed for reliability comparing end-tidal carbon dioxide pressure (P_ETCO2 ), S_pO2 , breathing frequency (f), and heart rate (beats/min).

Three hundred fifty-nine subjects were enrolled and had complete data. Two hundred fifty-two (70%) were discharged with supplemental oxygen. When comparing audible alarms with/without delays, there were 4,770/22,409 low P_ETCO2 , 1,601/6,246 high P_ETCO2 , 460/4,211 low frequency, 1,572/6,547 low heart rate, and 462/5,520 low S_pO2 alarms. Twenty-six (7.2%) subjects visited the emergency department in response to low S_pO2 audible alarms. Of these, 14 (3.9%) were diagnosed with a clinically relevant opioid-induced event, 95% CI 2.1%–6.5%, and 1 subject was administered naloxone by home caregivers.

This study demonstrates home monitoring of oxygenation (S_pO2 ), but not respiration (P_ETCO2 ), following ambulatory orthopedic procedures is feasible. Subjects at risk for clinically relevant opioid events may experience higher rates of postoperative complications, hospital readmissions, clinically relevant events, or death.

Mechanical power (MP) is useful for predicting the outcomes of attempts to liberate patients from mechanical ventilation. MP is computed based on measured variables derived to determine the power in joules required to breathe while receiving mechanical ventilation. The main objectives of this study were to calculate a cutoff value of MP that would predict successful liberation and to determine the prediction rate of liberation success based on this cutoff value.

This was a single-center retrospective study. Data from 110 tracheostomized subjects receiving mechanical ventilation were analyzed. We divided subjects into two groups based on ventilator liberation outcome. Confounding factors in subject background were adjusted using propensity score matching (PSM). Statistically significant differences in MP at tracheostomy and liberation success between liberation success and failure groups were examined. We calculated the MP cutoff value for successful liberation using the area under the curve of the receiver operating characteristic (ROC) and its corresponding prediction rate of liberation success.

The number of subjects in the successful liberation group was 79 and that of the failed liberation group was 31. The MP cutoff value and corresponding prediction rate for liberation success were 256.5 J/min (area under the curve-ROC = 0.839) and 92.2%, respectively. After PSM, the low MP group (n = 36), divided based on the MP cutoff value, had a significantly higher liberation success rate than the high MP group (n = 36), with an odds ratio of 19.95 (CI 3.95, 91.23, P < .001).

MP at tracheostomy was a strong predictor of successful ventilator liberation, and the prediction rate of liberation success based on the MP cutoff value was shown to be very high. We recommend that patients with low MP be actively considered for liberation. In contrast, those with high MP should continue weaning while simultaneously making early transfer arrangements if liberation is unsuccessful.

Rebound hypoxemia may occur after cessation of corticosteroid therapy for COVID-19 pneumonitis. We aimed to determine the incidence of this phenomenon in mechanically ventilated patients with COVID-19 completing corticosteroid therapy.

We conducted a retrospective observational cohort study across 2 tertiary ICUs from September to December 2021. We included all adult patients receiving invasive mechanical ventilation on completion of a 10-day course of dexamethasone for COVID pneumonitis. Our primary outcome was change in P_aO2 /F_IO2 ratio in the 7 days following cessation of dexamethasone. Secondary outcomes included duration of ventilation, frequency of corticosteroid recommencement, and mortality.

We studied 88 subjects. Median age was 61 years (interquartile range [IQR] 51–67), and median duration of mechanical ventilation was 14 days (IQR 11–26). On completion of dexamethasone, 62 subjects (70%) remained off corticosteroid therapy for the subsequent 7 days. Of these, 63% (n = 20) had a stable P_aO2 /F_IO2 ratio on day 7 (mean change 197 ± 42 mm Hg to 258 ± 83 mm Hg). Subjects who had a reduction in P_aO2 /F_IO2 ratio >20 mm Hg by day 7 (mean change 214 ± 68 mm Hg to 152 ± 78 mm Hg) were more likely to die in hospital (P < .001). These subjects had a higher C-reactive protein level at time of steroid cessation (204 ± 87 mg/L, P = .17), which remained persistently elevated (206 ± 89 mg/L, P = .01) on day 7. The 30% of subjects who recommenced steroids required a longer duration of ventilation (13.5 vs 24.5 d, P = .002) but showed no differences in ICU mortality (19% vs 27%, P = .43).

Rebound hypoxemia and steroid recommencement were common occurrences in mechanically ventilated subjects with COVID-19. Rebound hypoxemia was associated with higher mortality. Steroid recommencement was associated with longer duration of mechanical ventilation but no significant difference in mortality.

CPAP therapy has been shown to effectively reduce the risk of obstructive apnea and oxygen desaturation in procedural sedation. An economical approach to administering CPAP is through a Venturi adapter, which amplifies oxygen flows to produce pressures suitable for CPAP. The objective of this study was to evaluate the performance of four Venturi adapters across clinically relevant metrics including pressure-generation efficiency, inspired oxygen concentration (F_IO2 ), dilution of the end-tidal carbon dioxide (E_tCO2 ) sample for capnometry, and noise levels produced.

A benchtop simulator was used to evaluate Venturi adapters. The simulator was composed of a test lung, corrugated tubing to simulate a trachea, a silicone-molded face, an air-cushioned mask strapped to the face, a high-pressure oxygen source, and several Venturi adapters. The oxygen flows required to produce specific airway pressures were measured to evaluate pressure-generation efficiency, and the noise levels produced by the Venturi adapters at these pressures were recorded. CO₂ was infused into the test lung while the lung was ventilated, and the E_tCO2 measured at the mask was compared with a reference measurement taken from the trachea. F_IO2 was evaluated by ventilating the test lung and observing the steady-state oxygen concentration in the lung.

Each of the Venturi adapter designs provides their unique strengths and weaknesses. There appears to be a direct trade-off between high pressure-generation efficiency and high F_IO2 . There also appears to be a direct trade-off between high F_IO2 and the extent of dilution in the E_tCO2 sample. Some Venturi adapters produce high noise levels, which might result in patient discomfort and clinician unwillingness to use.

Variations in Venturi adapter designs create different clinical benefits. Clinicians should choose the Venturi adapter to best suit their present clinical needs.

Technologists must assure the accuracy and precision of pulmonary function equipment prior to testing patients. This study aimed to identify the sources of failure and unacceptable submission rates for spirometry volume linearity and syringe diffusing capacity of the lung for carbon monoxide (D_LCO) check quality control (QC). In addition, we explored whether the time between training and first QC submission affected overall percentage of unacceptable submissions.

Participants in a cross-sectional global study submitted QC for evaluation from October 2014 to May 2018 from 114 laboratories. Descriptive statistics summarized the percentage of unacceptable submissions and sources of failure for volume linearity and syringe D_LCO check maneuvers. Spearman’s rho described the correlation between site-specific unacceptable submission rates, and both days between training and the first unacceptable submission and the days between training and first submission.

The unacceptable submission rate from 5,083 volume linearity assessments was 10% compared with a 6.2% rate from 4,992 syringe D_LCO check maneuvers. Aggregate volume linearity rates of procedural errors (5.8%) and equipment errors (6.2%) were similar, whereas there were more syringe D_LCO check equipment errors (5.9%) than procedural errors (0.78%). The time between training and submitting a QC test was not related to overall unacceptable submission rates for volume linearity and syringe D_LCO check, r_sp = 0.11, P = .27 and r_sp = 0.19, P = .052, respectively. Higher unacceptable rates occurred when the first QC failure occurred close to the completion of training for volume linearity and syringe D_LCO check, r_sp = −0.41, P < .001 and r_sp = −0.38, P < .001, respectively.

A single QC training session does not adequately prepare technologists to conduct QC. Technologists need clear and consistent guidelines for conducting QC procedures and regular follow-up from experts to properly interpret QC findings, resolve equipment problems, and assure their testing systems are in-control.

We sought to define the prevalence of interventions by the Difficult Airway Response Team (DART) following its activation and investigate variables associated with increased risk of surgical airway and successful first intubation attempt.

We conducted a systematic review and included 14 studies in our meta-analysis. DART activations in ICUs, general wards, and emergency departments (EDs) were inspected. Variables collected included age, body mass index, and the percentage of subjects with a known difficult airway. Additional data included the DART activation location and time, the method of airway securement, and the number of first successful intubation attempts. The primary outcome was the prevalence of interventions by DART, defined as the number of subjects who underwent intubation by any method or received a surgical airway following consultation and evaluation by the DART. We used random-effects models. Moderator analyses and meta-regressions were performed to identify sources of heterogeneity and clinical variables associated with the prevalence of interventions by DART after its activation, respectively.

We included 4,092 subjects with a mean age of 57 (±3) years. Eleven studies reported 36% (1,030) female subjects. There were 3,441 DART activations among subjects in the ED, ICU, and ward. The pooled prevalence of the interventions by the DART, after activation was 76% (95% CI 0.41–0.93). The pooled prevalences of surgical airway placement and first successful intubation attempt was 6% (95% CI 0.03–0.10), and 72% (95% CI 0.61–0.81), respectively. Higher percentage of subjects undergoing video laryngoscopy (VL) was negatively correlated with higher percentage of surgical airway (coefficient −2.7, 95% CI −3.9 to −1.5) and positively correlated with first successful intubation attempts (coefficient 1.6, 95% CI 1.1–2.2).

The prevalence of interventions by DART after its activation was high, combined with lower prevalence of surgical airway demonstrate the benefits and efficacy of this emergent difficult airway program. Higher prevalence of successful first attempt was correlated with the usage of VL. Further research endeavors should investigate the efficiency of DART pathways in different institutions.