In two large-scale international studies, researchers shed light on the variability of international care in the intubation and extubation practices among critically ill patients receiving invasive mechanical ventilation, as well as adverse events.
The first of these was a prospective, multinational, observational study in which Karen E. A. Burns, MD, MSc, of the University of Toronto, Ontario, Canada, and colleagues assessed practice variations in the discontinuation of invasive mechanical ventilation (IMV) internationally and searched for associations between initial discontinuation events and outcomes, as well as the factors associated with the use of select discontinuation strategies and failed initial spontaneous breathing trials (SBTs).
They included 1,868 critically ill adults (mean age: 61.8 years; 62.8% men) from 142 ICUs in 19 countries within six regions who received IMV for at least 24 hours. Regions included Canada, India, the U.K., Europe, Australia/New Zealand, and the U.S.
In all, 22.7% had direct extubation, 49.8% had initial SBT that was successful in 81.8%, 8.0% had direct tracheostomy, and 19.5% died before any attempt to wean. Those who had an initial SBT had higher incidence of the following compared with those who underwent initial direct extubation:
- ICU mortality (10.3% versus 4.7%, respectively; absolute difference: 5.6%).
- Longer duration of ventilation (media 4.1 versus 2.9 days; absolute difference: 1.2 days).
- Longer ICU stay (median 8.1 versus 6.7 days; absolute difference: 1.4 days).
Patients who experienced failure of initial SBT had higher ICU mortality compared with those whose initial SBT passed (17.2% versus 8.8%, respectively; absolute difference: 8.4%), longer duration of ventilation (median 6.1 versus 3.5 days; absolute difference: 2.6 days), and longer ICU stay (median 10.6 versus 7.7 days; absolute difference: 2.8 days).
Patients who underwent late initial SBTs of more than 2.3 days after intubation underwent longer ventilation compared with those who had early initial SBTs (median 6.1 versus 2.1 days, respectively; absolute difference: 4.0 days), longer ICU stays (median 10.8 versus 5.9 days; absolute difference: 4.9 days), and longer hospital stays (median 22.8 versus 14.3 days; absolute difference: 8.5 days).
Burns et al found regional variations in the presence of written directives to guide care during weaning and to define the roles played by clinicians. The initial SBTs most commonly used included pressure support (PS) with positive pressure and positive end-expiratory pressure (PEEP; 49.1%) or T-piece (25.4%), while CPAP (10.8%) and PS without PEEP (9.5%) were less commonly used. T-piece SBTs were more commonly used in India (54.7%) and Europe (51.3%), while PS with PEEP SBTs were more common in Canada (48.0%), the U.K. (59.1%), the U.S. (77.6%), and Australia/New Zealand (75.0%).
The second study—the International Observational Study to Understand the Impact and Best Practices of Airway Management in Critically Ill Patients (INTUBE)—was very similar in that it was also an international, multicenter, prospective study in 1,857 critically ill patients from 197 sites in 29 countries across five continents who underwent tracheal intubation in ICUs, ERs, and wards (October 2018 to July 2019).
Vincenzo Russotto, MD, of the University of Milano-Bicocca, Monza, Italy, and colleagues included 2,964 patients (median age: 63 years; 62.6% men), in whom respiratory failure was the primary reason for intubation (52.3%), followed by neurological impairment (30.5%) and cardiovascular instability (9.4%).
A full 45.2% of these patients had at least one major adverse peri-intubation event, most commonly cardiovascular instability (42.6%), followed by severe hypoxemia (9.3%) and cardiac arrest (3.1%). Overall ICU mortality was high in these patients (32.8%).
In addition, although ketamine and etomidate are recommended as the induction agent of choice for the intubation of critically ill patients, they were seldom used in the study and were replaced by propofol as the most commonly used induction agent.
The use of waveform capnography for standard monitoring during intubation was low. In fact, in 68.9% of patients in whom the tracheal tube was misplaced in the esophagus, waveform capnography was not used.
Russotto and colleagues noted that “…clinicians relied on inaccurate clinical signs such as auscultation or chest movement for detection of esophageal intubation.”
In an accompanying editorial, Hayley B. Gershengorn, MD, of the University of Miami Miller School of Medicine, Miami, Florida, commented on the value gained from results from both studies, which together demonstrated the feasibility of such large-scale data collection and provided a more “complete picture of invasive mechanical ventilation globally.”
She wrote: “This information can inform clinical prognostication (e.g., Burns et al confirm existing evidence that approximately 1 in 10 extubations fail). Moreover, such baseline epidemiological data could be helpful to gauge clinical progress and more accurately power interventional trials aimed at changing practice.”
Gershengorn also noted the frequency of intubation clinical event rates in the various countries in the study from Russotto et al: in Europe, 48.5%; North America, 47.5%; and in South America, 47.6%. In comparison, the incidence of these events was only 30.3% in Africa.
In the INTUBE study, significant variations were found in the use of direct extubation, and ranged from 62.0% of attempts in Australia/New Zealand to 4.0% in the U.S.
According to Gershengorn, variability in practice is a given, but she added that determining what constitutes appropriate variability is complicated.
“Appropriate variability is largely that which can be attributed to intrinsic patient heterogeneity…,” she wrote, while excess variability is “largely driven by nonpatient factors,” including cultural and unrecognized influences that serve to drive practice patterns.
Ultimately, these two studies contribute to a better understanding of how to best care for critically ill patients.
“The reports by Russotto et al and Burns et al in this issue of JAMA represent ambitious large-scale data collection efforts that provide a window into international care variability involving intubation and extubation practices and adverse events among patients who received invasive mechanical ventilation. Variability can only be leveraged and addressed once its existence is laid bare for all to see. By doing so, these studies serve to advance current understanding of ways to improve care for critically ill patients,” Gershengorn concluded.
