Nasal high-flow oxygen therapy increases the mean nasopharyngeal airway pressure in adults, but the relationship between flow and pressure is not well defined.
To determine the relationship between ...flow and pressure with the Optiflow nasal high-flow oxygen therapy system.
We invited patients scheduled for elective cardiac surgery to participate. Measurements were performed with nasal high-flow oxygen at flows of 30, 40, and 50 L/min, with the patient's mouth both open and closed. Pressures were recorded over one minute of breathing, and average flows were calculated via simple averaging.
With the mouth closed, the mean ± SD airway pressures at 30, 40, and 50 L/min were 1.93 ± 1.25 cm H(2)O, 2.58 ± 1.54 cm H(2)O, and 3.31 ± 1.05 cm H(2)O, respectively. There was a positive linear relationship between flow and pressure.
The mean nasopharyngeal pressure during nasal high-flow oxygen increases as flow increases. Australian Clinical Trials Registry http://www.adhb.govt.nz/achicu/hot_2_airway_pressure.htm.
Previous research has demonstrated a positive linear correlation between flow delivered and airway pressure generated by high-flow nasal therapy. Current practice is to use flows over a range of ...30-60 L/min; however, it is technically possible to apply higher flows. In this study, airway pressure measurements and electrical impedance tomography were used to assess the relationship between flows of up to 100 L/min and changes in lung physiology.
Fifteen healthy volunteers were enrolled into this study. A high-flow nasal system capable of delivering a flow of 100 L/min was purpose-built using 2 Optiflow systems. Airway pressure was measured via the nasopharynx, and cumulative changes in end-expiratory lung impedance were recorded using the PulmoVista 500 system at gas flows of 30-100 L/min in increments of 10 L/min.
The mean age of study participants was 31 (range 22-44) y, the mean ± SD height was 171.8 ± 7.5 cm, the mean ± SD weight was 69.7 ± 10 kg, and 47% were males. Flows ranged from 30 to 100 L/min with resulting mean ± SD airway pressures of 2.7 ± 0.7 to 11.9 ± 2.7 cm H2O. A cumulative and linear increase in end-expiratory lung impedance was observed with increasing flows, as well as a decrease in breathing frequency.
Measured airway pressure and lung impedance increased linearly with increased gas flow. Observed airway pressures were in the range used clinically with face-mask noninvasive ventilation. Developments in delivery systems may result in this therapy being an acceptable alternative to face-mask noninvasive ventilation.
Nasal high flow (NHF) oxygen therapy and CPAP are modes of noninvasive respiratory support used to improve respiratory function in multiple patient groups. Both therapies provide positive pressure, ...although this varies during the respiratory cycle. The purpose of this study was to measure and compare the airway pressure generated during different phases of the respiratory cycle in patients receiving NHF at various gas flows.
Patients scheduled for elective cardiac surgery were invited to participate. Nasopharyngeal pressure measurements were performed using NHF with gas flows of 30, 40, and 50 L/min. All measurements were performed in random order, with the subject breathing with mouth closed.
During NHF the mean ± SD nasopharyngeal airway pressures were 1.5 ± 0.6, 2.2 ± 0.8, and 3.1 ± 1.2 at 30, 40, and 50 L/min using NHF. Analyses also determined the mean peak expiratory and mean expiratory plateau pressures.
The expiratory pressure during NHF was higher than the mean pressure previously reported for NHF. This may account in part for the disproportional clinical effects seen with NHF. (Australian Clinical Trials Registry www.anzctr.org.au ACTRN12609000305224).
Nonpharmaceutical interventions are implemented internationally to mitigate the spread of severe acute respiratory syndrome coronavirus 2 with the aim to reduce coronavirus disease 2019-related ...deaths and to protect the health system, particularly intensive care facilities from being overwhelmed. The aim of this study is to describe the impact of nonpharmaceutical interventions on ICU admissions of non-coronavirus disease 2019-related patients.
Retrospective cohort study.
Analysis of all reported adult patient admissions to New Zealand ICUs during Level 3 and Level 4 lockdown restrictions from March 23, to May 13, 2020, in comparison with equivalent periods from 5 previous years (2015-2019).
Twelve-thousand one-hundred ninety-two ICU admissions during the time periods of interest were identified.
Patient data were obtained from the Australian and New Zealand Intensive Care Society Adult Patient Database, Australian and New Zealand Intensive Care Society critical care resources registry, and Statistics New Zealand. Study variables included patient baseline characteristics and ICU resource use.
Nonpharmaceutical interventions in New Zealand were associated with a 39.1% decrease in ICU admission rates (p < 0.0001). Both elective (-44.2%) and acute (-36.5%) ICU admissions were significantly reduced when compared with the average of the previous 5 years (both p < 0.0001). ICU occupancy decreased from a mean of 64.3% (2015-2019) to 39.8% in 2020. Case mix, ICU resource use per patient, and ICU and hospital mortality remained unchanged.
The institution of nonpharmaceutical interventions was associated with a significant decrease in elective and acute ICU admissions and ICU resource use. These findings may help hospitals and health authorities planning for surge capacities and elective surgery management in future pandemics.
In a cardiothoracic and vascular intensive care unit, to compare nasal high-flow (NHF) oxygen therapy and standard high-flow face mask (HFFM) oxygen therapy in patients with mild to moderate ...hypoxemic respiratory failure.
In a prospective randomized comparative study, 60 patients with mild to moderate hypoxemic respiratory failure were randomized to receive NHF or HFFM. We analyzed the success of allocated therapy, noninvasive ventilation rate, and oxygenation.
Significantly more NHF patients succeeded with their allocated therapy (P = .006). The rate of noninvasive ventilation in the NHF group was 3/29 (10%), compared with 8/27 (30%) in the HFFM group (P = .10). The NHF patients also had significantly fewer desaturations (P = .009).
NHF oxygen therapy may be more effective than HFFM in treating mild to moderate hypoxemic respiratory failure.
Proton pump inhibitors (PPIs) or histamine-2 receptor blockers (H2RBs) are often prescribed for patients as stress ulcer prophylaxis drugs in the intensive care unit (ICU). The comparative effect of ...these drugs on mortality is unknown.
To compare in-hospital mortality rates using PPIs vs H2RBs for stress ulcer prophylaxis.
Cluster crossover randomized clinical trial conducted at 50 ICUs in 5 countries between August 2016 and January 2019. Patients requiring invasive mechanical ventilation within 24 hours of ICU admission were followed up for 90 days at the hospital.
Two stress ulcer prophylaxis strategies were compared (preferential use with PPIs vs preferential use with H2RBs). Each ICU used each strategy sequentially for 6 months in random order; 25 ICUs were randomized to the sequence with use of PPIs and then use of H2RBs and 25 ICUs were randomized to the sequence with use of H2RBs and then use of PPIs (13 436 patients randomized by site to PPIs and 13 392 randomized by site to H2RBs).
The primary outcome was all-cause mortality within 90 days during index hospitalization. Secondary outcomes were clinically important upper gastrointestinal bleeding, Clostridioides difficile infection, and ICU and hospital lengths of stay.
Among 26 982 patients who were randomized, 154 opted out, and 26 828 were analyzed (mean SD age, 58 17.0 years; 9691 36.1% were women). There were 26 771 patients (99.2%) included in the mortality analysis; 2459 of 13 415 patients (18.3%) in the PPI group died at the hospital by day 90 and 2333 of 13 356 patients (17.5%) in the H2RB group died at the hospital by day 90 (risk ratio, 1.05 95% CI, 1.00 to 1.10; absolute risk difference, 0.93 percentage points 95% CI, -0.01 to 1.88 percentage points; P = .054). An estimated 4.1% of patients randomized by ICU site to PPIs actually received H2RBs and an estimated 20.1% of patients randomized by ICU site to H2RBs actually received PPIs. Clinically important upper gastrointestinal bleeding occurred in 1.3% of the PPI group and 1.8% of the H2RB group (risk ratio, 0.73 95% CI, 0.57 to 0.92; absolute risk difference, -0.51 percentage points 95% CI, -0.90 to -0.12 percentage points; P = .009). Rates of Clostridioides difficile infection and ICU and hospital lengths of stay were not significantly different by treatment group. One adverse event (an allergic reaction) was reported in 1 patient in the PPI group.
Among ICU patients requiring mechanical ventilation, a strategy of stress ulcer prophylaxis with use of proton pump inhibitors vs histamine-2 receptor blockers resulted in hospital mortality rates of 18.3% vs 17.5%, respectively, a difference that did not reach the significance threshold. However, study interpretation may be limited by crossover in the use of the assigned medication.
anzctr.org.au Identifier: ACTRN12616000481471.
Cardiac surgery utilizing cardiopulmonary bypass (CPB) is one of the most common forms of major surgery. Cardiac surgery-associated multiorgan dysfunction (CSA-MOD) is well recognized and includes ...acute kidney injury (AKI), hepatic impairment, myocardial damage, and postoperative neurologic deficit. Pathophysiology of CSA-MOD involves numerous injurious pathways linked to the use of CPB including oxidative stress and formation of reactive iron species. During cardiac surgery with CPB, arterial return blood is oxygenated to supranormal levels. This study aimed to determine whether the avoidance of arterial hyperoxemia decreased oxidative stress and reduced the severity of the multiorgan dysfunction in patients undergoing cardiac surgery utilizing CPB.
The study was a multicenter, open-label, parallel-group, randomized controlled study of the avoidance of arterial hyperoxemia versus usual care in patients undergoing cardiac surgery involving CPB. Primary outcome was the incidence and severity of AKI. Secondary outcomes included serum biomarkers for CSA-MOD, duration of mechanical ventilation, and length of intensive care and hospital stay.
A total of 298 patients were randomized and analyzed at two hospitals in New Zealand and Australia. Mean PaO2 was significantly different between groups during CPB. There was no difference in the development of AKI (intervention arm 72.0% vs. usual care 66.2%; difference, -5.8% 95% CI, -16.1 to 4.7%; P = 0.28), other markers of organ damage, or intensive care unit and hospital length of stay.
Avoiding modest hyperoxemia during CPB failed to demonstrate any difference in AKI, markers of organ damage, or length of stay.
Mechanical ventilation requires an endotracheal tube. Airway management includes endotracheal suctioning, a frequent procedure for patients in the ICU. Associated risks of endotracheal suctioning ...include hypoxia, atelectasis, and infection. There is currently no evidence about the safety of avoiding endotracheal suction. We aimed to assess the safety of avoiding endotracheal suction, including at extubation, in cardiac surgical patients who were mechanically ventilated for ≤ 12 h.
We conducted a single-center, noninferiority, randomized controlled trial in a cardiac ICU in a metropolitan tertiary teaching hospital. Subjects were assigned to either avoidance of endotracheal suction or to usual care including endotracheal suctioning during mechanical ventilation. In total, we screened 468 patients and randomized 249 subjects (usual care,
= 125; intervention,
= 124). Subjects were elective cardiac surgical patients anticipated to receive ≤ 12 h of mechanical ventilation. The primary outcome was the Formula: see text/Formula: see text on room air 6 h after extubation, with a noninferiority margin of 10% (lower bound of one-sided 95% CI to be < 30).
There were no differences in group characteristics at baseline. The primary analysis was a per-protocol analysis performed on 154 subjects. The median Formula: see text/Formula: see text was 323 for the intervention group and 311 for the standard care group (median difference = 12, one-sided 95% CI -14.3). The results were consistent when using an intention-to-treat analysis and a 97.5% CI. There were no differences between groups in complications or safety measures, including the escalation of oxygen therapy.
Endotracheal suctioning can be safely minimized or avoided in low-risk patients who have had cardiac surgery and are expected to be ventilated for < 12 h after surgery.
IntroductionIt is plausible that a longer duration of nutrition intervention may have a greater impact on clinical and patient-centred outcomes. The Intensive Nutrition care Therapy comparEd to usual ...care iN criTically ill adults (INTENT) trial will determine if a whole hospital nutrition intervention is feasible and will deliver more total energy compared with usual care in critically ill patients with at least one organ system failure.Methods and analysisThis study is a prospective, multicentre, unblinded, parallel-group, phase II randomised controlled trial (RCT) conducted in 23 hospitals in Australia and New Zealand. Mechanically ventilated critically ill adult patients with at least one organ failure who have been in intensive care unit (ICU) for 72–120 hours and meet all of the inclusion and none of the exclusion criteria will be randomised to receive either intensive or usual nutrition care. INTENT started recruitment in October 2018 and a sample size of 240 participants is anticipated to be recruited in 2022. The study period is from randomisation to hospital discharge or study day 28, whichever occurs first, and the primary outcome is daily energy delivery from nutrition therapy. Secondary outcomes include daily energy and protein delivery during ICU and in the post-ICU period, duration of ventilation, ventilator-free days, total bloodstream infection rate and length of hospital stay. All other outcomes are considered tertiary and results will be analysed on an intention-to-treat basis.Ethics and disseminationEthics approval has been received in Australia (Alfred Hospital Ethics Committee (HREC/18/Alfred/101) and Human Research Ethics Committee of the Northern Territory Department of Health (2019-3372)) and New Zealand (Northern A Health and Disability Ethics Committee (18/NTA/222). Results will be disseminated in an international peer-reviewed journal(s), at scientific meetings and via social media.Trial registration numberNCT03292237.
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