Combined Use of Alkaline Agents With Low-Flow Extracorporeal Carbon Dioxide Removal in Carbon Dioxide Inhalation Models Preserving Inspiratory Efforts.

Background: Low-flow extracorporeal CO 2 removal (ECCO 2 R), managed using a renal replacement platform, is useful in achieving lung-protective ventilation with low tidal volume. However, its capacity for CO 2 elimination is limited. Whether this system is valuable in reducing strong inspiratory efforts in respiratory failure is unclear. The combined use of alkaline agents with low-flow ECCO 2 R might be useful in hypercapnic subjects preserving inspiratory efforts. Methods: This study examined the effects of low-flow ECCO 2 R on respiratory status and investigated the effects of NaHCO 3 , trometamol, and saline on respiratory status during low-flow ECCO 2 R in CO 2 inhalation models. Results: Although low-flow ECCO 2 R did not significantly change the respiratory rate (92.2% ± 24.3% [mean ± standard deviation] of that before ECCO 2 R), it reduced minute ventilation (MV) (78.9% ± 13.5% of that before ECCO 2 R). The addition of NaHCO 3 improved acidemia but did not change MV compared with that of the saline group (0.451 ± 0.026 L/min/kg body weight [BW] vs. 0.556 ± 0.138 L/min/kg BW, respectively). The addition of trometamol improved acidemia and reduced MV compared with that of the saline group (0.381 ± 0.050 L/min/kg BW vs. 0.556 ± 0.138 L/min/kg BW, respectively). The total amounts of CO 2 removed during ECCO 2 R in the NaHCO 3 group were lower than those in the saline and trometamol groups. Conclusion: The low-flow ECCO 2 R reduced MV in subjects preserving spontaneous breathing efforts with CO 2 overload. The addition of NaHCO 3 improved acidemia but did not change MV, whereas the addition of trometamol improved acidemia and reduced MV.

Accuracy of lung ultrasound examinations of residual congestion performed by novice residents in patients with acute heart failure.

AIMS: The popularity of B-line-guided congestion assessment by lung ultrasound (LUS) has been increasing. However, the ability of novice residents to detect residual congestion with B-line-guided assessment by LUS after decongestion treatment is poorly understood. In this study, we investigated whether novice residents (no prior echocardiography experience) can acquire the skills for B-line-guided residual congestion assessment and whether the range of variation in assessment is acceptable in actual clinical use. METHODS AND RESULTS: The study included 30 postgraduate first-year novice residents and an expert. The residents underwent training for LUS. At the end of the training session, a set of 15 LUS videos was provided to the residents, and they were asked to estimate the number of B-lines in each video. When the residents' answers greatly differed from the correct answer, we provided feedback to raise awareness of the discrepancies. After the training session, the residents performed residual congestion assessment by LUS after decongestion treatment in patients hospitalized with acute heart failure. The residents identified residual congestion in 57% of the patients. The sensitivity and specificity to identify residual congestion by the residents were 90% and 100%, respectively. The inter-operator agreement between the residents and the expert was substantial (κ = 0.86). The Spearman rank correlation coefficient for the B-lines between the expert and each resident was very high at 0.916 (P < 0.0001). CONCLUSIONS: After a brief lecture, novice residents can achieve proficiency in quantifying B-lines on LUS and can reliably identify residual congestion on LUS.

Time definition of reintubation most relevant to patient outcomes in critically ill patients: a multicenter cohort study.

BACKGROUND: Reintubation is a common complication in critically ill patients requiring mechanical ventilation. Although reintubation has been demonstrated to be associated with patient outcomes, its time definition varies widely among guidelines and in the literature. This study aimed to determine the association between reintubation and patient outcomes as well as the consequences of the time elapsed between extubation and reintubation on patient outcomes. METHODS: This was a multicenter retrospective cohort study of critically ill patients conducted between April 2015 and March 2021. Adult patients who underwent mechanical ventilation and extubation in intensive care units (ICUs) were investigated utilizing the Japanese Intensive Care PAtient Database. The primary and secondary outcomes were in-hospital and ICU mortality. The association between reintubation and clinical outcomes was studied using Cox proportional hazards analysis. Among the patients who underwent reintubation, a Cox proportional hazard analysis was conducted to evaluate patient outcomes according to the number of days from extubation to reintubation. RESULTS: Overall, 184,705 patients in 75 ICUs were screened, and 1849 patients underwent reintubation among 48,082 extubated patients. After adjustment for potential confounders, multivariable analysis revealed a significant association between reintubation and increased in-hospital and ICU mortality (adjusted hazard ratio [HR] 1.520, 95% confidence interval [CI] 1.359-1.700, and adjusted HR 1.325, 95% CI 1.076-1.633, respectively). Among the reintubated patients, 1037 (56.1%) were reintubated within 24 h after extubation, 418 (22.6%) at 24-48 h, 198 (10.7%) at 48-72 h, 111 (6.0%) at 72-96 h, and 85 (4.6%) at 96-120 h. Multivariable Cox proportional hazard analysis showed that in-hospital and ICU mortality was highest in patients reintubated at 72-96 h (adjusted HR 1.528, 95% CI 1.062-2.197, and adjusted HR 1.334, 95% CI 0.756-2.352, respectively; referenced to reintubation within 24 h). CONCLUSIONS: Reintubation was associated with a significant increase in in-hospital and ICU mortality. The highest mortality rates were observed in patients who were reintubated between 72 and 96 h after extubation. Further studies are warranted for the optimal observation of extubated patients in clinical practice and to strengthen the evidence for mechanical ventilation.

Timing of tracheostomy and patient outcomes in critically ill patients requiring extracorporeal membrane oxygenation: a single-center retrospective observational study.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is an integral method of life support in critically ill patients with severe cardiopulmonary failure; however, such patients generally require prolonged mechanical ventilation and exhibit high mortality rates. Tracheostomy is commonly performed in patients on mechanical ventilation, and its early implementation has potential advantages for favorable patient outcomes. This study aimed to investigate the association between tracheostomy timing and patient outcomes, including mortality, in patients requiring ECMO. METHODS: We conducted a single-center retrospective observational study of consecutively admitted patients who were supported by ECMO and underwent tracheostomy during intensive care unit (ICU) admission at a tertiary care center from April 2014 until December 2021. The primary outcome was hospital mortality. Using the quartiles of tracheostomy timing, the patients were classified into four groups for comparison. The association between the quartiles of tracheostomy timing and mortality was explored using multivariable logistic regression models. RESULTS: Of the 293 patients treated with ECMO, 98 eligible patients were divided into quartiles 1 (≤ 15 days), quartile 2:16-19 days, quartile 3:20-26 days, and 4 (> 26 days). All patients underwent surgical tracheostomy and 35 patients underwent tracheostomy during ECMO. The complications of tracheostomy were comparable between the groups, whereas the duration of ECMO and ICU length of stay increased significantly as the quartiles of tracheostomy timing increased. Patients in quartile 1 had the lowest hospital mortality rate (19.2%), whereas those in quartile 4 had the highest mortality rate (50.0%). Multivariate logistic regression analysis showed a significant association between the increment of the quartiles of tracheostomy timing and hospital mortality (adjusted odds ratio for quartile increment:1.55, 95% confidence interval 1.03-2.35, p for trend = 0.037). CONCLUSIONS: The timing of tracheostomy in patients requiring ECMO was significantly associated with patient outcomes in a time-dependent manner. Further investigation is warranted to determine the optimal timing of tracheostomy in terms of mortality.

Anesthetic management using high-flow nasal cannula therapy during cardiac catheter examination of a neonate with hypoplastic left heart syndrome.

BACKGROUND: Sedation during cardiac catheter examination in neonates with complex congenital heart disease is challenging, as even the slightest change in the circulatory or respiratory status can lead to hemodynamic collapse. Here, we report a case wherein we achieved adequate sedation with a high-flow nasal cannula (HFNC) for catheter examination in a neonate with a congenital cardiac anomaly. CASE PRESENTATION: An 11-day-old boy with hypoplastic left heart syndrome was scheduled for a cardiac catheter examination prior to the Norwood procedure. He underwent bilateral pulmonary artery banding (PAB) on day 1 and was receiving dobutamine, milrinone, alprostadil, and dexmedetomidine in addition to air and nitrogen insufflation via HFNC, which was applied following extubation on day 3 and nitrogen therapy on day 6 owing to persistent pulmonary overcirculation symptoms (tachypnea and low arterial blood pressure) despite bilateral PAB. A catheter examination was performed on day 11 with careful monitoring of expired carbon dioxide and observation of chest wall motion. Adequate sedation was provided with supplemental midazolam and fentanyl along with HFNC without tracheal intubation. CONCLUSIONS: The findings from this case suggest that HFNC is a safe and effective tool for oxygenation during cardiac catheter examination under sedation in neonates.

Combined short-axis out-of-plane and long-axis in-plane approach versus long-axis in-plane approach for ultrasound-guided central venous catheterization in infants and small children: A randomized controlled trial.

The ultrasound-guided long-axis in-plane approach for central venous catheterization in infants and small children can prevent posterior wall penetration. The combined short-axis out-of-plane and long-axis in-plane approach reportedly prevents such penetration in adults. To test the hypothesis of non-inferiority of the combined approach to the long-axis in-plane approach, we compared the two approaches in infants and small children. Patients were randomized based on whether they underwent ultrasound-guided internal jugular vein catheterization using the combined or long-axis in-plane approach. Posterior wall penetration rates, first-attempt success rates, overall success rates within 20 min; scanning, puncture, and procedure durations; and number of attempts were compared between the groups. In the combined and long-axis in-plane groups (n = 55 per group), the posterior wall penetration rates were 5.5% (3/55) and 3.6% (2/55) (P = 0.65), the first-attempt success rates were 94.5% (52/55) and 92.7% (51/55) (P = 0.70), and the overall success rates within 20 min were 100% (55/55) and 98.2% (54/55) (P = 0.32), respectively. In the combined and long-axis in-plane groups, the median (interquartile range) scanning durations were 21 (16.5-34.8) s and 47 (29.3-65) s (P<0.0001), the puncture durations were 114 (83-170) s and 74 (52.3-117.3) s (P = 0.0002), and the procedure durations were 141 (99-97.8) s and 118 (88.5-195.5) s (P = 0.14), respectively. The median number of attempts was 1 (interquartile range: 1-1, range: 1-3) in both groups (P = 0.72). Similar to the long-axis in-plane approach, the combined approach for internal jugular vein catheterization prevented posterior wall penetration in infants and small children. Trial registration: This trial was registered before patient enrollment in the University Hospital Medical Information Network Clinical Trials Registry, registration number UMIN000039387 (https://upload.umin.ac.jp/cgi-bin/ctr/ctr_view_reg.cgi?recptno=R000044907).

Impact of an infectious disease physician-led carbapenem postprescription feedback on prescribing behavior in a Japanese tertiary hospital: A before-after study.

INTRODUCTION: There is an insufficient number of infectious disease (ID) physicians in Japan. Hence, we considered a strategy to implement antimicrobial stewardship under these resource-limited settings. METHODS: We compared carbapenem consumption, measured as days of therapy per 100 patient-days, between 24-month baseline and 12-month intervention periods. During the intervention period, an ID physician provided daily advises to prescribers against prolonged carbapenem use (≥14 days). Additionally, we sent all doctors a table containing the weekly point prevalence aggregate of carbapenem use of each department for 7-13 and ≥ 14 days via e-mail. RESULTS: Among the 1241 carbapenem courses during the intervention period, the ID physician provided a total of 96 instances of feedback regarding carbapenem use for ≥14 days, with an acceptance rate of 76%. After the initiation of the intervention, the trend in monthly carbapenem consumption changed (coefficient: -0.62; 95% CI: -1.15 to -0.087, p = 0.024), and its consumption decreased (coefficient: -0.098; 95% CI: -0.16 to -0.039, p = 0.002) without an increase in the consumption of broad-spectrum antimicrobials or in-hospital mortality. Interestingly, the monthly number of carbapenem courses, but not the duration of carbapenem use, significantly decreased (coefficient: -3.02; 95% CI: -4.63 to -1.42, p = 0.001). The carbapenem-related annual estimated savings after the intervention was $83,745, with a 22% cost reduction. CONCLUSIONS: Our ID physician-led daily intervention with weekly feedback regarding long-term carbapenem use was effective in reducing antimicrobial consumption. Such feedback may be useful in changing the prescribing behavior and promoting appropriate antimicrobial usage even in resource-limited settings.

Effects of Ventilatory Settings on Pendelluft Phenomenon During Mechanical Ventilation.

BACKGROUND: Pendelluft phenomenon is defined as the displacement of gas from a more recruited nondependent (ND) lung region to a less recruited dependent (D) lung region. This phenomenon may cause lung injury. Thus, a lung model for pendelluft was established, and the effects of ventilatory settings on pendelluft were examined. METHODS: Two sets of the twin-bellows-type training test lung (TTL) model were utilized. One set of bellows simulated the diaphragm, and the other simulated the lung. One TTL model represented the ND region, and the other represented the D region. The lung bellows were connected to each other and were ventilated with 1 ventilator. The diaphragm bellows were ventilated with 2 synchronized ventilators that regulated pleural pressure levels. We simulated pendelluft by applying different pleural pressure levels to the D and ND bellows. The increment of the tidal volume in the D region from the "no breathing effort" condition was defined as the pendelluft volume. The effects of ventilator settings, such as ventilatory modes, triggering sensitivity, inspiratory pressurization, and inspiratory cycling-off, were examined. The changes in tidal volumes in the D region based on the control settings were compared to assess the severity of pendelluft. RESULTS: The gas flow from the D region to the ND region was found to be essential in pendelluft, but the severity of this phenomenon was not always proportional to gas flows. The severity increased with the increase in the differences in pleural pressure levels between the ND and D regions, and it was amplified by the difference in lung mechanics between the ND and D regions. However, the ventilator settings had minimal effect on the severity of pendelluft. CONCLUSIONS: The pendelluft was affected by the heterogeneity of lung mechanics and pleural pressure. Furthermore, a minimal association was observed between the ventilator settings and the severity of pendelluft.

Effects of alkaline agents on respiratory characteristics in rabbit models of respiratory failure.

This study aimed to investigate the effects of alkaline agents on reducing strong inspiratory effort. Rabbits with hypercapnia or lung injury, induced via repeated lung lavage following injurious ventilation, were treated with Saline, NaHCO3, or Trometamol. In the hypercapnia, minute ventilation and tidal volume were unchanged during NaHCO3 administration; however, one hour after the end of NaHCO3 these parameters decreased (82.1+/-7.8 %, 90.8+/-6.0 % of the baseline, respectively, p < 0.05). Trometamol reduced minute ventilation, tidal volume, and respiratory rate after infusion (59.8+/-19.0 %, 87.0+/-9.2 %, 68.2+/-18.4 % of the baseline, respectively, p < 0.05). Alkaline agents did not cause a large change in the cerebrospinal fluid acid-base balance. In the lung injury model, NaHCO3 and Trometamol had little effect on ventilation. However, Trometamol reduced transpulmonary pressure. Trometamol exerted more inhibitory effects on ventilation than NaHCO3 in the hypercapnia model, and Trometamol reduced the transpulmonary pressure in the lung injury model.

Long-Axis In-Plane Approach Versus Short-Axis Out-of-Plane Approach for Ultrasound-Guided Central Venous Catheterization in Pediatric Patients: A Randomized Controlled Trial.

OBJECTIVES: The aim of this study was to compare the occurrence of posterior wall puncture between the long-axis in-plane and the short-axis out-of-plane approaches in a randomized controlled trial of pediatric patients who underwent cardiovascular surgery under general anesthesia. DESIGN: Prospective randomized controlled trial. SETTING: Operating room of Osaka Women's and Children's Hospital. PATIENTS: Pediatric patients less than 5 years old who underwent cardiovascular surgery. INTERVENTIONS: Ultrasound-guided central venous catheterization using the long-axis in-plane approach and short-axis out-of-plane approach. MEASUREMENTS AND MAIN RESULTS: The occurrence of posterior wall puncture was compared between the long-axis in-plane and short-axis out-of-plane approaches for ultrasound-guided central venous catheterization. Patients were randomly allocated to a long-axis group or a short-axis group and underwent ultrasound-guided central venous catheterization in the internal jugular vein using either the long-axis in-plane approach (long-axis group) or the short-axis out-of-plane approach (short-axis group). After exclusion, 97 patients were allocated to the long-axis (n = 49) or short-axis (n = 48) groups. Posterior wall puncture rates were 8.2% (4/49) and 39.6% (19/48) in the long-axis and short-axis groups, respectively (relative risk, 0.21; 95% CI, 0.076-0.56; p = 0.0003). First attempt success rates were 67.3% (33/49) and 64.6% (31/48) in the long-axis and short-axis groups, respectively (relative risk, 1.04; 95% CI, 0.78-1.39; p = 0.77). Overall success rates within 20 minutes were 93.9% (46/49) and 93.8% (45/48) in the long-axis and short-axis groups, respectively (relative risk, 0.99; 95% CI, 0.90-1.11; p = 0.98). CONCLUSIONS: The long-axis in-plane approach for ultrasound-guided central venous catheterization is a useful technique for avoiding posterior wall puncture in pediatric patients, compared with the short-axis out-of-plane approach.

Predictors of Successful Extubation in Reintubated Patients: The Impact of Fluid Balance during the 24 Hours Prior to Extubation.

How to cite this article: Tanaka A, Yamashita T, Koyama Y, Uchiyama A, Fujino Y. Predictors of Successful Extubation in Reintubated Patients: The Impact of Fluid Balance during the 24 Hours Prior to Extubation. Indian J Crit Care Med 2019;23(7):344-345.

Attaining Low Tidal Volume Ventilation During Patient Triggered Ventilation in Sedated Subjects.

BACKGROUND: Low tidal volume (VT) ventilation has become the preferred approach in patients in the ICU. Sedation reduces VT by attenuating respiratory drive. Even in deep sedation, some patients exhibit high VT. We aimed to determine factors associated with low VT ventilation in deeply sedated subjects who exhibited an inspiratory effort by examination of the acid/base balance using the Stewart model. METHODS: The medical records of 630 consecutive subjects admitted to the ICU over 1 y were reviewed retrospectively, and daily data sets of patients with a persistent inspiratory effort, PaO2 /FIO2 < 300 mm Hg, PEEP > 5 cm H2O, and a Richmond Agitation Sedation Scale score of -4 or -5 who received assisted pressure-regulated ventilation were collected. The data sets were stratified into high VT (≥ 8 mL/kg predicted body weight [PBW]) and low VT (> 8 mL/kg PBW) groups. RESULTS: Among 235 matched data sets from 100 subjects, 101 and 134 data sets were in the low VT and high VT groups, respectively. Set pressure was not different between the groups. PEEP was lower in the low VT group, and opioids were more frequently used in the high VT group. Strong ion difference (SID) was higher in the low VT group. Multivariate analysis revealed that higher SID, lower total nonvolatile weak anion (ATOT), and absence of opioid administration were associated with attaining low VT ventilation. Furthermore, VT/PBW and SID demonstrated a weak inverse correlation, whereas VT/PBW and ATOT exhibited a weak correlation. VT/PBW was lower in the group with higher SID and lower ATOT, indicating a tendency of metabolic alkalosis. CONCLUSIONS: Despite weak effects of high SID and low ATOT, efficient management of the buffering function might be a feasible strategy to achieve low VT ventilation.

A Comparison of the Adjustable Ranges of Inspiratory Pressurization During Pressure Controlled Continuous Mandatory Ventilation of 5 ICU Ventilators.

BACKGROUND: Faster inspiratory pressurization can improve patient-ventilator synchrony and reduce the patient's work of breathing during pressure controlled continuous mandatory (PC-CMV) ventilation. The characteristics of the pressurization ramp settings are not standardized across ventilators from different manufacturers. We performed a bench test of 5 models of ICU ventilators to examine the effects of pressurization ramp settings on the actual pressurization. METHODS: A twin-bellows lung model was used, in which one bellow simulates inspiratory muscle activity and the other simulates an adult normal lung model. We made the inspiratory effort by changing the tidal volume of the inspiratory muscle bellow. The effect of pressurization ramp settings on the performance of each ventilator was examined at 3 inspiratory effort levels (ie, none, ordinary, and strong). The pressurization ramp was set at 4 or 5 evenly divided steps from the minimum to maximum for each ventilator. The following parameters were measured: tidal volume, mean airway pressure, maximal inspiratory flow, time to maximal flow, and pressure-time products at 0.3 s (PTP0.3) and 0.5 s (PTP0.5) from the beginning of inspiration. PTP0.3 and PTP0.5 indicated levels of inspiratory pressurization. RESULTS: A proportional increase in PTP0.3 and PTP0.5 was observed with an increase in the pressurization ramp settings of the recent models of ventilators. PTP0.3 and PTP0.5 at ordinary and strong effort levels were similar in the recent models of ventilators. The actual adjustable ranges of PTP0.3 and PTP0.5 associated with change in the pressurization ramp settings differed between the 5 ventilators. CONCLUSIONS: The adjustable ranges of the pressurization were largely different among the different types of ventilators. The actual absolute inspiratory pressurization during PC-CMV varied between the different ventilators even at similar pressurization ramp settings. Users should be mindful of the differences in the pressurization ramp settings.

[Spontaneous Respiration Technique for Pediatric Microlaryngeal Surgery without Endotracheal Intubation].

We report the anesthetic management of microlaryngeal surgery in children using tubeless total intravenous anesthesia (TIVA) without endotracheal intubation under spontaneous breathing. In 9 patients (median age : 4.9 yr. range 1 months-14 years, body weight : 17 kg, range 3-61 kg), 19 procedures were performed with TIVA using propofol and remifentanil. The median time from the start of TIVA to rigid laryngoscope insertion was 11 minutes. Propofol 15.7 mg x kg(-1) x hr(-1) and remifentanil 0.05 µg x kg(-1) x min(-1) was infused in this interval. Laryngospasm was observed in two cases, but it responded to a bolus of propofol (0.5-1.0 mg x kg(-1)) and additional topical anesthesia with 1% lidocaine. Three children were found apneic after a bolus administration of remifentanil or after increasing the rate of remifentanil infusion accompanied with desaturation and their tracheae were intubated. The spontaneous respiration technique using TIVA without intubation provides an excellent view of the operative field while allowing stable anesthesia. Further studies are required to establish the optimal dose of propofol and remifentanil and the timing of rigid laryngoscope insertion.