Abstract
Background:
Patient performance on extubation readiness tests (ERTs) informs the decision to extubate after cardiac surgery. ERT pass criteria at our center include age-based breathing frequencies and weight-adjusted tidal volumes (VT). Evidence validating these criteria in children after cardiac surgery is limited. We hypothesized that higher breathing frequency and/or lower VT during the final ERT prior to extubation, even if meeting pass criteria, would be associated with re-intubation within 48 h.
Methods:
This was an observational, retrospective cohort study involving children <18 years of age receiving invasive mechanical ventilation for >24 h after cardiac surgery for Society of Thoracic Surgery (STAT) Mortality category ≥3 from May 2022 to April 2024. The primary outcome was extubation failure. The secondary outcome was the interval between the first passed ERT and extubation. Factors associated with re-intubation were explored using univariate and multivariable analyses.
Results:
Two hundred sixty-eight subjects met inclusion criteria with a median (interquartile range) age of 58.5 (6.1–210.2) days and weight of 4.2 (3.3–7.5) kg. Thirty (11.2%) subjects experienced extubation failure. These subjects had a higher breathing frequency during the ERT (42 [36–52] vs 36 [28–44] breaths/min, P = .01). On univariate analysis, subjects who required re-intubation were younger, had longer courses of invasive mechanical ventilation, and more frequently received preoperative invasive mechanical ventilation, delayed sternal closure, or were in a higher STAT category. Multivariable analysis revealed no association between re-intubation and breathing frequency (adjusted odds ratio [aOR] = 1.02, 95% CI: 0.99–1.06), VT (aOR = 1.0, 95% CI: 0.78–1.25), or the Rapid Shallow Breathing Index (RSBI; expressed as breathing frequency/VT) (aOR = 1.11, 95% CI: 0.96–1.27). The interval between the first passed ERT and extubation did not differ between groups (1.4 [0.5–3.6] vs 1.2 [0.4–2.4] days, P = .22).
Conclusions:
There was no association between the final ERT breathing frequency, VT, or RSBI and re-intubation within 48 h.
Keywords: congenital heart disease, extubation readiness testing, mechanical ventilation, airway extubation
Introduction
Postoperative management of children after complex surgical repairs of congenital heart defects often involves a period of invasive mechanical ventilation.1,2 This may be necessary because of prolonged cardiopulmonary bypass times, fluid shifts, exposure to blood products, and marked changes in cardiopulmonary physiology.3,4 However, the attendant risks of prolonged invasive mechanical ventilation (eg, ventilator-associated pneumonia, diaphragm weakness, delirium, delayed feeding) underscore the importance of timely liberation.5 Complicating the decision of when to extubate, these patients are at increased risk of requiring re-intubation relative to the general pediatric ICU population, and extubation failure is independently associated with in-hospital mortality.6,7
Extubation readiness tests (ERTs) are performed prior to liberation from invasive mechanical ventilation to assess a patient’s ability to maintain adequate respiratory effort and hemodynamic stability under minimal support from the ventilator.8,9 Criteria for a successful ERT vary among institutions but generally incorporate age- and weight-appropriate ranges for breathing frequency and weight-adjusted tidal volume (VT) indicative of adequate pulmonary mechanics and gas exchange.10–13 Data validating these ranges in children after high-risk congenital heart surgery are sparse. Furthermore, patient- and surgery-specific factors may influence performance thresholds associated with optimal rates of successful liberation from invasive mechanical ventilation.14–17
In this study, we evaluated current ERT criteria and their associations with extubation failure following cardiac surgery. We hypothesized that higher breathing frequency and lower VT on the final ERT prior to extubation, even if meeting pass criteria, would be associated with increased risk of re-intubation within 48 h.
Methods
We performed an observational, retrospective cohort study using data from all patients extubated in our Pediatric Cardiac Intensive Care Unit (PCICU) between May 2022 and April 2024. The study was determined to be exempt by the Duke University Institutional Review Board. We included all patients <18 years of age admitted to the PCICU who required invasive mechanical ventilation for >24 h after a complex cardiac surgery, classified as Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) categories of 3, 4, 5 (range = 1–5, with STAT 5 carrying the highest risk of mortality), as well as patients implanted with a ventricular assist device (VAD).18 Patients transferred out of the PCICU prior to extubation, those who died prior to extubation, or those with a tracheostomy were excluded. For subjects with multiple courses of invasive mechanical ventilation, each course was considered independently. If a subject was intubated preoperatively and remained intubated postoperatively, that course of invasive mechanical ventilation was included in the analysis.
Data from the ERT and at the time of extubation were collected by the respiratory therapist (RT) responsible for patient care and from the electronic medical record. At our institution, all patients meeting extubation readiness criteria undergo a daily ERT unless otherwise ordered. ERTs were conducted by placing subjects in pressure support (PS) mode with a PEEP of 5 cm H2O and PS of 5 cm H2O. A detailed report of our institution’s ERT protocol is provided in Supplementary Data. Most subjects had ERTs lasting 60 min; shorter tests (30 min) required approval by the medical provider and were typically used for low-risk subjects with short durations of invasive mechanical ventilation. Longer tests (90+ min) could also be requested by the medical provider, usually for subjects with risk factors for extubation failure. In all cases, the RT responsible for the subject determined whether the ERT was passed or failed. Breathing frequency and VT at the end of the ERT were recorded prior to restoring the ventilator settings to pre-ERT settings. For subjects who failed the ERT, the reason for failure was noted, and ERTs were resumed the next day (or sooner if ordered by the medical provider) provided the subject continued to meet readiness criteria. If extubation was attempted, the total duration of the invasive mechanical ventilation course as well as ventilator settings just prior to the ERT, including set frequency, PEEP, Δ pressure (PS or inspiratory pressure), mean airway pressure, and FIO2 , were collected.
Subject demographics, medical history, STAT category, indication for invasive mechanical ventilation, receipt of preoperative invasive mechanical ventilation, delayed sternal closure, and use of cardiopulmonary bypass during surgery or extracorporeal membrane oxygenation (ECMO) after surgery were extracted from the medical record by trained RTs. In cases where invasive mechanical ventilation was begun preoperatively, the age at initiation and duration of invasive mechanical ventilation include this preoperative period. The presence of cardiac risk factors for extubation failure including single ventricle physiology, significant atrioventricular valve regurgitation (moderate or worse), and significant ventricular dysfunction (moderate or worse) was recorded. Respiratory factors including history of extubation failure within the same hospital encounter (pre- or postoperatively), period between the first passed ERT and extubation, endotracheal tube size, the presence of a cuff leak at the time of extubation, and the use of dexamethasone prior to extubation were recorded, as was the modality of postextubation respiratory support. Other clinical factors felt to be related to extubation failure risk and recorded were the use of neuromuscular blockade for >48 h and whether enteral nutrition was initiated postoperatively prior to extubation. These data were entered along with the ERT data into a secure Research Electronic Data Capture (REDCap) database (REDCap, hosted at Duke University Medical Center, North Carolina).19
Our primary outcome was extubation failure, defined as re-intubation within 48 h of a planned extubation attempt. The secondary outcome was the interval between the first passed ERT and extubation. We used counts (percentages) and medians (25th–75th percentiles, interquartile range [IQR]) to describe categorical and continuous variables, respectively. We compared the distributions of clinical characteristics, ERT data, and clinical outcomes using the chi-square test, Fisher exact test, or Wilcoxon rank-sum test, where appropriate. For the ERT data, we examined breathing frequency, VT, and the Rapid Shallow Breathing Index (RSBI; expressed as breathing frequency/VT in breaths/min/mL/kg) as continuous variables. We also examined VT as a categorical variable using ranges of <4 mL/kg, 4–5 mL/kg, and >5 mL/kg. These categories were chosen to retrospectively evaluate a recent change in our ERT pass criteria to lower the VT threshold to >4 mL/kg from >5 mL/kg.
To further assess the association between breathing frequency and VT on the final ERT prior to extubation and extubation failure, we used a multivariable logistic regression model. Variables included in the model were breathing frequency, VT, and any variables with a P < .10 on univariate analysis. Additionally, we fit a second, similar model substituting RSBI for breathing frequency and VT, as this index has previously been associated with the likelihood of re-intubation.20 Results were reported as odds ratios (ORs), and statistical significance was set at P < .05. Statistical analyses were conducted using R version 4.4.1 (R Foundation for Statistical Computing, Vienna, Austria) and RStudio version 2024.12.0.
Results
A total of 268 subjects met the inclusion criteria, of whom 71 had multiple courses of mechanical ventilation. Thirty subjects (11.2%) were reintubated within 48 h. In univariate analysis, subjects reintubated within 48 h after extubation were younger (median 13 [IQR 1–107] vs 75 [7–212] days, P = .034), more likely to receive invasive mechanical ventilation prior to surgery (57% vs 31%, P = .02), more likely to have undergone delayed sternal closure (67% vs 39%, P = .01), and had a longer course of invasive mechanical ventilation prior to extubation (8.4 [4.9–14.4] vs 6.1 [2.9–11.3] days, P = .02). There were no statistically significant differences between the groups in sex, weight at extubation, history of prematurity, and diagnosis of genetic anomaly. Cardiac risk factors including single ventricle physiology, significant atrioventricular valve regurgitation, or ventricular systolic dysfunction by echocardiography were also not significantly different between groups. Use of prolonged neuromuscular blockade (>48 h) and initiation of enteral nutrition prior to extubation were also similar between groups. Clinical characteristics of the entire cohort and each group are shown in Table 1.
Table 1.
Subject demographics and clinical variables
| Variable | All (N = 268) | Reintubated (n = 30) | Not Reintubated (n = 238) | P |
|---|---|---|---|---|
| Age at initiation of invasive mechanical ventilation, daysa | 58 (6–210) | 13 (1–107) | 75 (7–212) | .034 |
| Age at initiation by category | .08 | |||
| Neonate, 0–28 days | 115 (43) | 18 (60) | 97 (41) | |
| Infant, 29–365 days | 112 (42) | 7 (23) | 105 (44) | |
| Child, >1 y | 41 (15) | 5 (17) | 36 (15) | |
| Gender, male | 181 (68) | 21 (70) | 160 (67) | .76 |
| Weight, kg | 4.2 (3.3–7.5) | 3.8 (3.1–5.2) | 4.4 (3.3–7.6) | .09 |
| Comorbidities | ||||
| Prematurity | 6 (2) | 0 (0) | 6 (3) | .38 |
| Genetic syndrome | 12 (5) | 1 (3) | 11 (5) | .75 |
| Reason for mechanical ventilation | ||||
| Postoperative | 254 (95) | 28 (93) | 226 (9) | .71 |
| Respiratory failure | 54 (20) | 8 (27) | 46 (19) | .35 |
| Cardiac arrest | 4 (1) | 0 (0) | 4 (2) | .47 |
| Procedure | 11 (4) | 1 (3) | 10 (4) | .82 |
| Other | 17 (6) | 4 (13) | 13 (6) | .10 |
| STAT category | .01 | |||
| 3 | 61 (23) | 2 (7) | 59 (25) | |
| 4 | 133 (50) | 14 (47) | 119 (50) | |
| 5 | 54 (20) | 8 (27) | 46 (19) | |
| VAD | 20 (8) | 6 (20) | 14 (6) | |
| Operative factors | ||||
| Cardiopulmonary bypass | 253 (94) | 30 (100) | 223 (94) | .37 |
| ECMO | 43 (16) | 3 (10) | 40 (17) | .34 |
| Delayed sternal closure | 112 (42) | 20 (67) | 92 (39) | .01 |
| Cardiac factors | ||||
| Single ventricle physiology | 80 (30) | 12 (40) | 68 (29) | .20 |
| AV valve regurgitation | 113 (42) | 17 (57) | 96 (40) | .23 |
| Ventricular dysfunction | 31 (12) | 6 (20) | 25 (11) | .29 |
| Respiratory factors | ||||
| Preoperative invasive mechanical ventilationa | 91 (34) | 17 (57) | 74 (31) | .02 |
| History of extubation failure | 59 (22) | 6 (20) | 53 (22) | .78 |
| Other factors | ||||
| NMB >48 h | 74 (28) | 12 (40) | 62 (26) | .20 |
| Feeding prior to extubation | 149 (56) | 15 (50) | 134 (56) | .51 |
Categorical variables are presented as n (%) and continuous variables as median (IQR), P values calculated using chi-square test or Wilcoxon rank-sum test.
AV, atrioventricular; ECMO, extracorporeal membrane oxygenation; IQR, interquartile range; NMB, neuromuscular blockade; STAT category, Society of Thoracic Surgeons–European Association for Cardiothoracic Surgery Congenital Heart Surgery Mortality categories; VAD, ventricular assist device.
For invasive mechanical ventilation courses that began prior to cardiac surgery and continued into the postoperative period, the age at initiation of invasive mechanical ventilation includes preoperative values.
Subjects who required re-intubation had a higher mandatory breathing frequency prior to their final ERT (24 [20–26] vs 20 [18–24] breaths/min, P < .01) but other ventilator settings, including D pressure, PEEP, mean airway pressure, and FIO2, were not significantly different between groups. All but one subject (99.6%) passed an ERT prior to extubation (Table 2). There was no difference in the total number of passed or failed ERTs between groups. Subjects who were reintubated had higher breathing frequency (42 [36–53] vs 35 [28–44] breaths/min, P = .01) on the final ERT prior to extubation. VT in mL/kg was not significantly different between groups, and there was no difference in the RSBI. The interval between the first passed ERT and extubation was similar between the reintubated and nonreintubated groups (1.4 [0.5–3.6] vs 1.2 [0.4–2.4] days, P = .22). No differences between groups were observed in the size of the endotracheal tube, the presence of a cuff leak prior to extubation, and whether the subject received dexamethasone prior to extubation. Subjects who were reintubated had a higher net fluid balance over the 24 h prior to extubation than those who did not require re-intubation; however, this did not reach the prespecified threshold for statistical significance (+50 [−18 to 127] vs −10 [−120 to 99] mL, P = .052). The initial modality of noninvasive respiratory support after extubation, which could include noninvasive ventilation, CPAP, heated, humidified high-flow nasal cannula, simple nasal cannula, or room air, was not different between groups (Table 2).
Table 2.
Pre- and postextubation respiratory data
| Variable | All (N = 268) | Reintubated (n = 30) | Not Reintubated (n = 238) | P |
|---|---|---|---|---|
| Ventilator settings prior to extubation | ||||
| Set frequency, breaths/min | 20 (18–24) | 24 (20–26) | 20 (18–24) | .01 |
| Δ pressure, cm H2O | 11 (10–14) | 12 (10–14) | 11 (10–13) | .12 |
| PEEP, cm H2O | 6 (6-6) | 6 (6-6) | 6 (6-6) | .25 |
| Mean airway pressure, cm H2O | 9 (8–10) | 9 (9–11) | 9 (8–10) | .14 |
| FIO2 | 0.35 (0.30–0.45) | 0.39 (0.30–0.40) | 0.35 (0.28–0.45) | .65 |
| Duration of invasive mechanical ventilation course, daysa | 6 (3–12) | 8 (5–14) | 6 (3–11) | .02 |
| Endotracheal tube size, mm | 3.5 (3.5-3.5) | 3.5 (3.0–3.5) | 3.5 (3.5-3.5) | .21 |
| Cuff leak present | 211 (79) | 26 (87) | 185 (78) | .40 |
| Dexamethasone use | 91 (34) | 13 (43 | 78 (33) | .45 |
| Performance during ERT prior to extubation | ||||
| Breathing frequency, breaths/min | 37 (29–45) | 42 (36–53) | 35 (28–44) | .01 |
| VT, mL/kg | 7.0 (5.9–7.9) | 7.0 (5.9–7.7) | 7.0 (5.9–8.0) | .79 |
| RSBI | 5.4 (3.8–7.3) | 6.0 (4.6–8.3) | 5.3 (3.6–7.1) | .08 |
| VT category | .71 | |||
| >5 mL/kg | 245 (92) | 27 (90) | 218 (92) | |
| 4–5 mL/kg | 20 (7.5) | 3 (10) | 17 (7) | |
| <4 mL/kg | 3 (1) | 0 (0) | 3 (1) | |
| Total passed ERTs | .80 | |||
| 0 | 1 (0.3) | 0 | 1 (0.4) | |
| 1 | 103 (38) | 11 (37) | 92 (39) | |
| 2 | 78 (29) | 9 (30) | 69 (29) | |
| 3 | 46 (17) | 4 (13) | 42 (18) | |
| ≥4 | 40 (15) | 6 (20) | 35 (15) | |
| Total failed ERTs | .96 | |||
| 0 | 132 (49) | 15 (50) | 117 (49) | |
| 1 | 54 (20) | 6 (20) | 48 (20) | |
| 2 | 40 (15) | 3 (10) | 37 (16) | |
| 3 | 18 (7) | 2 (7) | 16 (7) | |
| ≥4 | 24 (9) | 4 (13) | 20 (8) | |
| Time from first passed ERT to extubation, days | 1.3 (0.4–2.4) | 1.4 (0.5–3.6) | 1.2 (0.4–2.4) | .22 |
| Support at extubation | .85 | |||
| NIV | 34 (13) | 3 (10) | 31 (13) | |
| CPAP | 18 (7) | 1 (3) | 17 (7) | |
| HFNC | 209 (78) | 26 (87) | 183 (77) | |
| Simple nasal cannula | 5 (2) | 0 | 4(2) | |
| Room air | 2 (1) | ;0 | 2 (1) |
Categorical variables are presented as n (%) and continuous variables as median (IQR). P values are calculated using the chi-square test or the Wilcoxon rank-sum test.
For invasive mechanical ventilation courses that began prior to cardiac surgery and continued into the postoperative period, the duration of the course includes the preoperative duration.
ERT, extubation readiness test; HFNC, high-flow nasal cannula; NIV, noninvasive mechanical ventilation; RSBI, ratio of breathing frequency to weight-adjusted tidal volume; VT, weight-adjusted tidal volume.
The multivariable logistic regression models showed no statistically significant association between re-intubation and breathing frequency during the ERT (adjusted OR [aOR] = 1.02, 95% CI: 0.99–1.06), weight-adjusted VT (aOR = 1.0, 95% CI: 0.78–1.25), or RSBI (aOR = 1.1, 95% CI: 0.96–1.3). The only independent predictor of re-intubation within 48 h detected by our model was VAD implantation (aOR = 13.7, 95% CI: 2.2–120) (Table 3, Supplementary Table S1).
Table 3.
Multivariable logistic regression of factors associated with re-intubation
| Variable | OR (95% CI) | P |
|---|---|---|
| Weight, kg | 0.94 (0.79–1.01) | .29 |
| STAT category | ||
| STAT 4 | 2.7 (0.67–17.8) | .22 |
| STAT 5 | 2.1 (0.42–15.9) | .41 |
| VAD | 13.7 (2.2–120) | .01 |
| Preoperative invasive mechanical ventilation | 1.5 (0.57–3.7) | .42 |
| Delayed sternal closure | 2.2 (0.81–5.8) | .13 |
| Duration of invasive mechanical ventilation, days | 0.98 (0.93–1.01) | .23 |
| Final ERT breathing frequency, breaths/min | 1.02 (0.99–1.06) | .19 |
| Final ERT VT, mL/kg | 1 (0.78–1.25) | .97 |
ERT, extubation readiness test; OR, odds ratio; STAT category, Society of Thoracic Surgeons–European Association for Cardiothoracic Surgery Congenital Heart Surgery Mortality Categories; VAD, ventricular assist device; VT, weight-adjusted tidal volume.
Discussion
In this cohort of high-risk children receiving invasive mechanical ventilation after cardiac surgery, we found a re-intubation rate of 11.2%, which is consistent with rates reported in previous studies.6,15,21,22 The novelty in this study rests with the finding that, for subjects who passed an ERT prior to extubation, the final ERT values (breathing frequency, weight-adjusted VT, and RSBI) did not have a clear association with extubation failure. Our findings that younger age, preoperative invasive mechanical ventilation, and longer course of mechanical ventilation were associated with extubation failure are in line with earlier reports, although these associations became non-significant after adjusting for baseline differences between groups.17,23–25 Although some studies report associations between cardiac risk factors such as single ventricle physiology, significant AV valve regurgitation, or ventricular systolic dysfunction and extubation failure, none were detected in our cohort.26,27 However, we did note that subjects who required delayed sternal closure had greater odds of extubation failure on univariate, but not on multivariable, analysis. Our study evaluated the relationship between ERT metrics and the risk of re-intubation. For subjects who passed an ERT and were then extubated, we did not find an independent association between subject breathing frequency, weight-adjusted VT, or the RSBI and extubation failure. Although subjects who were reintubated within 48 h had higher breathing frequency during their ultimate ERT by univariate analysis, the younger age of the reintubated group may have been a confounder, as the difference disappeared when controlling for this in our multivariable regression model. Interestingly, a prior study that examined only neonatal subjects also noted a higher breathing frequency during the ERT in subjects who required re-intubation relative to those who did not, although they did not include this parameter in their subsequent multivariable analysis.26 This suggests that the observed relationship between breathing frequency during ERT and re-intubation may be influenced by factors other than age alone.
The use of ERTs to determine the suitability of a child for liberation from invasive mechanical ventilation is widely practiced in pediatric cardiac ICUs.13 ERTs typically involve the integration of clinical, laboratory, and ventilator data into a “pass/fail” result based on ranges for each variable thought to be associated with low risk of re-intubation. Although the method of conducting the ERT, most notably whether any and, if so, what method of ventilatory support should be provided (ie, variable vs fixed PS, or CPAP alone), has been the subject of much research and debate, the criteria for a passing result have been less rigorously evaluated.28–30 This is especially the case in the pediatric cardiac population, which has largely been excluded from clinical trials conducted in the general PICU setting.31
In this study, we sought to determine whether our center’s current ERT pass thresholds for breathing frequency and VT could be further refined by analyzing variation in ERT performance within the designated pass range and its association with re-intubation. For example, a higher observed re-intubation rate for subjects with a breathing frequency during ERT approaching the cutoff for a failed test could indicate that a narrower pass range would be expected to decrease extubation failure. On the contrary, if subjects with values near the cutoff were no more likely to be reintubated than those well within the range, this could support liberalizing the pass criteria to facilitate earlier extubation without a concomitant rise in re-intubation.
One illustrative example of this point can be seen in the stratification of subjects by their ERT weight-adjusted VT. Historically, a VT >6 mL/kg during an ERT has been considered an adequate threshold for extubation in pediatrics. However, we and others have previously shown that this can be associated with false-positive ERT failure, where the child fails the ERT despite being able to tolerate extubation. Accordingly, our center’s original protocol used a 5 mL/kg threshold for ERT success, which is congruent with other published work.32 This study permits the evaluation of a more recent change to lower the VT threshold to 4mL/kg. Our results suggest that this change is not likely to have been associated with increased risk of extubation failure in patients who would previously have failed that criterion.
Ultimately, it appears that our ERT criteria reasonably capture patients who are ready for ventilator liberation. Our results do show that mechanical circulatory support with a VAD was independently associated with extubation failure in our cohort. Detailed data including VAD type, settings, and duration of therapy were not available in our dataset; however, a more granular exploration of extubation failure in VAD patients is warranted to determine the nature of this association and whether adjustments to the standard extubation protocol are needed for this high-risk subgroup.
Intriguingly, we observed that subjects requiring reintubation had a higher net fluid balance in the 24 h prior to extubation than those who were reintubated, although this narrowly missed the threshold for statistical significance. Excess fluid accumulation worsening pulmonary edema and lung compliance is a plausible mechanism for an increased likelihood of extubation failure, and excess fluid accumulation and acute kidney injury after cardiopulmonary bypass are each associated with worse ICU outcomes including duration of invasive mechanical ventilation.33 The limitations of our dataset preclude additional analysis of the association of fluid accumulation and kidney injury on ERT and extubation outcomes; however, this bears further investigation in future studies.
This study has a number of important limitations. Although focusing on a single center ensured that ERT criteria were uniform, it restricts our findings’ generalizability to other centers whose clinical practice may vary. The retrospective nature of our study limited us to variables routinely charted by our RTs during ERTs. Charting continuously obtained variables such as breathing frequency and VT as a single representative number also involves a degree of individual judgment that may introduce bias; additionally, the use of single breathing frequency and VT values from the end of the ERT period obscures intra-ERT variability that others have shown can provide useful prognostic information.34 Although comparable to other studies of pediatric subjects after congenital cardiac surgery, our sample size is small relative to prior studies evaluating ERTs in a general PICU population, thus limiting our ability to discern associations with smaller effect sizes. Finally, we did not observe a relationship between breathing frequency and VT in our study, although our re-intubation rate was low, and we may not have had adequate statistical power to detect differences when values were close to the threshold.
Conclusions
When subjects’ respiratory performance on the final ERT prior to extubation fell within our center’s “pass” criteria, there was no significant association between breathing frequency, VT, or RSBI (as long as they fell within the passing range) and re-intubation. Similarly, the interval between the first passed ERT and extubation did not differ between subjects who required re-intubation and those who did not. Given the lack of equipoise for extubating children who failed our center’s established ERT criteria, our data are primarily hypothesis-generating for future studies to determine whether more liberal “pass” criteria may promote earlier extubation without increasing reintubation rates.
Supplementary Material
QUICK LOOK
Current knowledge
Prolonged invasive mechanical ventilation is associated with worse outcomes after high-risk cardiac surgery in children; however, extubation failure is also associated with increased mortality. Extubation readiness tests (ERTs) are used to inform the timing of extubation by identifying patients at lower risk of extubation failure. Criteria for passing an ERT vary by center and are frequently based on evidence from patients without congenital heart disease.
What this paper contributes to our knowledge
We examined factors associated with extubation failure for a large cohort of subjects who received postoperative invasive mechanical ventilation after high-risk cardiac surgery. For subjects who passed their ERT and were subsequently extubated, respiratory performance within our center’s pass criteria was not independently associated with extubation failure. This supports a hypothesis that stricter pass criteria would be unlikely to result in a significant reduction in extubation failure.
Acknowledgments
The authors would like to acknowledge the contributions of the RTs serving the Duke PCICU for their exceptional patient care and their assistance with recording ERT data used in this study.
Funding Information
A.G.M. has received research funding from the American Association for Respiratory Care. E.J.T. receives funding from the National Institute of Child Health and Human Development (K23-HD116971). A.T.R. receives research funding from Philips Healthcare. The authors received no direct financial support for the research, authorship, and/or publication of this article.
Footnotes
Ethical Considerations
The study was determined to be exempt from the requirement for approval by the Duke University Institutional Review Board.
Consent to Participate
An informed consent requirement was waived by the Duke University Institutional Review Board.
Author Disclosure Statement
A.T.R. receives royalties from Elsevier and Springer. A.G.M. is a section editor for Respiratory Care, is a member of the scientific advisory board for Aerogen, has received honoraria from Fisher and Paykel, and salary support from the National Institutes of Health. The other authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data Availability
The datasets analyzed for this study are available from the corresponding author upon reasonable request.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
The datasets analyzed for this study are available from the corresponding author upon reasonable request.