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Dual-Mode Weaning Strategy for Difficult-Weaning Tracheotomy Patients: A Feasibility Study

Duan, Jun MD; Guo, Shuliang MD; Han, Xiaoli MD; Tang, Xiaokui MD; Xu, Lulu MD; Xu, Xia MD; Liu, Yucun MD; Jia, Jinwei MD; Huang, Shicong MD; Wu, Yamei MD

doi: 10.1213/ANE.0b013e31825c7dba
Critical Care, Trauma, and Resuscitation: Research Reports
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BACKGROUND: Tracheotomy patients who are difficult to wean from ventilation consume a substantial portion of intensive care unit (ICU) resources. These patients also typically undergo a long period of mechanical ventilation (MV) and have a high mortality rate. The efficacy of a dual-mode weaning strategy (alternation of invasive and noninvasive MV) in tracheotomy patients who are difficult to wean is unknown.

METHODS: We performed this prospective, randomized, controlled trial in a 17-bed respiratory ICU from July 2009 to October 2011. After tracheotomy, patients who failed for 3 consecutive days in a spontaneous breathing trial were enrolled (n = 32) and randomly allocated to either the dual-mode (n = 15) or conventional (n = 17) weaning group.

RESULTS: Compared with the conventional group, patients in the dual-mode group had a shorter duration of MV during the entire study (median 38 days, interquartile range [IQR]: 28–53 vs 59, IQR: 39–88, P = 0.03) and after randomization (median 10 days, IQR: 4–21 vs 37, IQR: 16–51, P < 0.01). They also had a shorter ICU stay (median 44 days, IQR: 32–54 vs 72, IQR: 52–102, P = 0.01), a lower mortality rate during weaning (1 of 15 vs 7 of 17, P = 0.04), and a lower rate of pulmonary infection after randomization (3 of 15 vs 12 of 17, P < 0.01).

CONCLUSIONS: Dual-mode weaning is a promising strategy for treating tracheotomy patients who are difficult to wean. In a small cohort of patients with tracheotomies, we demonstrated that dual-mode weaning reduced the total duration of MV and ICU stay; we recommend additional studies to assess its effect on pulmonary infections and mortality.

Published ahead of print June 13, 2012 Supplemental Digital Content is available in the text.

From the Department of Respiratory Medicine, the First Affiliated Hospital, Chongqing Medical University, Chongqing, People's Republic of China.

The authors declare no conflicts of interest.

Reprints will not be available from the authors.

Address correspondence to Shuliang Guo, MD, Department of Respiratory Medicine, the First Affiliated Hospital, Chongqing Medical University, Youyi Road 1, Yuzhong District, Chongqing 400016, P. R. China. Address e-mail to guosl999@163.com and copy one to guosl999@sina.com.

Accepted April 16, 2012

Published ahead of print June 13, 2012

Noninvasive mechanical ventilation (NIV) facilitates discontinuing invasive mechanical ventilation (IMV) and reduces the duration of ventilator-associated pneumonia (VAP). A meta-analysis and systematic review concluded that noninvasive weaning is associated with a reduced mortality rate, reduced VAP, and shorter intensive care unit (ICU) and hospital stays compared with conventional weaning.1 The switch from IMV to NIV has been focused on the pulmonary infection control window or one or multiple consecutive failures of the spontaneous breathing trial (SBT).24 However, all of these studies focused on tracheally intubated patients.

The failure of continuous weaning is common in tracheotomy patients, especially patients undergoing prolonged mechanical ventilation. It is unclear how best to wean these patients from IMV. We have devised an alternative method of weaning tracheotomy patients, dual-mode ventilation, that alternates IMV and NIV. The purpose of this study was to determine whether this strategy improves weaning success and reduces complications compared with traditional weaning methods.

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METHODS

This feasibility study was performed in the respiratory ICU of a tertiary care university hospital from July 2009 to October 2011. Inclusion criteria were (1) IMV, (2) tracheotomy, (3) age 18 years or older, and (4) SBT failure for 3 consecutive days after tracheotomy. Exclusion criteria were (1) facial or cranial trauma or surgery, (2) facial abnormalities, (3) recent gastric or esophageal surgery, (4) active upper gastrointestinal bleeding, and (5) lack of cooperation.4 This study was approved by our ethics committee. Written informed consent was obtained from the patients themselves or their next of kin. Prolonged MV was defined as at least 6 hours of IMV for >21 consecutive days.5 Successful weaning was defined as no need for IMV or NIV support during the remainder of the patient's hospitalization. The patient's participation in the study ended when he or she was discharged, was transferred to a rehabilitation hospital, or died. The primary outcome was the total duration of MV from randomization to successful weaning or death. The secondary outcomes were (1) the total duration of MV, the ICU stay, and the hospital stay; and (2) the rate of pulmonary infection, the mortality rate, and the 60-day survival rate after randomization.

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General Management of Patients

The ventilator mode was synchronized intermittent mandatory ventilation (pressure control) plus pressure support ventilation for all patients. The control pressure, support pressure, fraction of oxygen, positive end-expiratory pressure (PEEP), setting breathing frequency, and other variables of the ventilator were titrated to maintain the pulse oximeter saturation (SpO2) approximately 95%, tidal volume (VT) approximately 8 mL/kg, pH approximately 7.4, and measured respiratory frequency <25 breaths/min. When the patient stabilized, the parameters of the ventilator (the pressure, setting breathing frequency, and fraction of oxygen) were decreased for weaning. When the patient passed the daily screen, the SBT was performed. If the patient failed the SBT, the variables were set according to the same titration protocol described previously. Strategies to prevent VAP (e.g., elevation of the head of the bed, hand hygiene, oral hygiene) were used in every patient. Sedation was routinely managed to reach a Ramsay score of 3 to 4 when patients became agitated, patient-ventilator asynchrony occurred, or other clinical conditions occurred in which the patients needed to relax. Sedation was interrupted each morning. If the patient remained calm, sedation was stopped. If not, sedation was continued. Sputum and chest radiographs were routinely examined every 3 to 5 days or when the clinicians suspected that pneumonia had occurred. The blood specimen was cultured when the patient's temperature was above 38°C. A diagnosis of pneumonia was based on the presence of a new or progressive radiographic infiltrate (by chest radiographs) plus at least 2 clinical features (temperature above 38°C, leukocytosis [leukocyte count ≥ 10 × 103/mm3] or leucopenia [leukocyte count ≤ 4 × 103/mm3], purulent secretions, and appearance or worsening of respiratory insufficiency).6 The study profile is summarized in Figure 1.

Figure 1

Figure 1

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Criteria for Daily Screen

Patients were screened daily for evidence of some reversal of the underlying cause of respiratory failure, adequate oxygenation (PaO2 ≥60 mm Hg, fraction of inspired oxygen [FIO2] ≤0.5, PaO2/FIO2 ≥150, PEEP ≤5 cm H2O), temperature between 35°C and 38°C, systolic blood pressure between 90 and 180 mm Hg (without vasopressor therapy or with only a low-dose vasopressor such as dopamine or dobutamine <5 μg/kg/min), heart rate ≤120 bpm, and a Glasgow Coma Scale score ≥13.7

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Criteria for SBT

If patients passed the daily screen, 30 to 120 minutes of an SBT was conducted. The SBT was performed as follows: the ventilation mode was switched to spontaneous breath mode, pressure support was set at 6 cm H2O, and no change was made in FIO2 or PEEP.

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Criteria for SBT Failure

The criterion for SBT failure was the presence of one of the following: respiratory rate ≥35 bpm; f/VT ≥105; SpO2 ≤90% at FIO2 of ≥0.4; heart rate ≥140 or ≤50 bpm; systolic blood pressure ≥180 or ≤90 mm Hg; pH ≤7.3; a >10 mm Hg increase in PaCO2; diminishing consciousness or diaphoresis; and clinical signs indicating respiratory muscle fatigue, labored breathing, or both.7

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Procedure

Patients were screened daily. If the patient passed the daily screen and subsequently passed the SBT, attempts were made to wean the patient. Patients who failed 3 consecutive days of SBT after tracheotomy were enrolled in the present study and randomly allocated to either the dual-mode or conventional weaning group.

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Dual-Mode Weaning Group

Patients who were allocated to the dual-mode weaning group after SBT failure received full ventilation support with synchronized intermittent mandatory pressure plus pressure support ventilation for 2 hours. After 2 hours of full support, patients' cuffs were deflated and their tubes capped (although the tube remained in the airway), and patients received NIV (S/T mode, BiPAP Vision; Respironics Inc., Andover, MA) through a facemask (Fig. 2).

Figure 2

Figure 2

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Shift from IMV to NIV

The procedure for shifting from IMV to NIV was as follows. (1) We instructed the patient on how to cooperate with the NIV. (2) We cleared secretions in the airway with a suction catheter. Secretions above the cuff were cleared by subglottic secretion drainage. (3) We elevated the head of the bed at a 45° angle and oxygenated the patient's lungs with 100% oxygen. (4) We adjusted the initial NIV variables to S/T mode, respiratory rate = 16 breaths/min, inspiratory positive airway pressure (IPAP) = 10 cm H2O, expiratory positive airway pressure = 4 cm H2O, pressure increase time = 0.4 second, and FIO2 = 100%. (5) We disconnected the IMV, deflated the cuff, capped the tube, and fitted the patient with a facemask. (6) The nurse and respiratory therapist remained at the patient's bedside and continuously encouraged and instructed him or her on how to cooperate with NIV. (7) When the patient acclimated to NIV, we began to adjust the variables. The pressure increase time was adjusted to 0.2 second. The IPAP was titrated according to the VT, minute ventilation, respiratory rate, arterial blood gas test, and patient's clinical symptoms. The IPAP was kept at no more than 25 cm H2O. The expiratory positive airway pressure was kept at 4 cm H2O. The FIO2 was titrated according to the bedside oximeter and arterial blood gas test to keep the SpO2 approximately 95%. (8) The nurse and respiratory therapist strongly encouraged the patient to cough up sputum when there was a clinical indication of sputum in the airway. If the patient was unable or too weak to cough, we uncapped the tube and suctioned the airway every 2 hours or more often if necessary. If the patient recovered the ability to cough, the suction interval time was increased until the patient could cough out all of the sputum. (9) When the patient recovered from respiratory failure and NIV support had continued for >48 hours, weaning was considered. We first attempted to stop the NIV for 5 minutes (keeping the patient oxygenated by nasal catheter), and if the patient could tolerate spontaneous breathing, we increased the duration without NIV to 10 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 8 hours, 12 hours, 24 hours, and even 48 hours according to arterial blood gas tests, clinical symptoms, and the patient's requirement. If the patient felt tired or experienced shortness of breath, we reconnected him or her to NIV. When the patient felt better, we stopped the NIV again until it was totally removed. (10) When the patient recovered from respiratory failure and regained the ability to cough, and the amount of sputum was reduced, decannulation was performed.

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Shift from NIV to IMV

Patients were shifted from NIV to IMV when one of the following conditions was present: heart rate ≥140 bpm for >10 minutes; respiratory rate ≥35 breaths/min for >10 minutes; PaCO2 ≥80 mm Hg; PaO2 ≤60 mm Hg; FIO2 ≥0.6; systolic blood pressure ≥180 or ≤90 mm Hg for >10 minutes; diminishing consciousness or diaphoresis; or clinical signs indicating respiratory muscle fatigue, labored breathing, or both.

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Shift from IMV to NIV Again

When the reason for the shift from NIV to IMV had been corrected and the patient had stabilized for >24 hours, the patient was shifted back to NIV.

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Conventional Weaning Group

If a patient in the conventional weaning group passed the daily screen and then passed the 30- to 120-minute SBT, we stopped IMV and oxygenated the patient with supplemental oxygen through a tracheotomy tube. We closely monitored the patient's lungs and increased the duration without IMV to 10 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 8 hours, 12 hours, 24 hours, and even 48 hours according to arterial blood gas tests, clinical symptoms, and patient's requirement. If the patient could not tolerate spontaneous breathing, the ventilator was reconnected. We gradually reduced the pressure support and increased the amount of spontaneous breathing time until the patient could tolerate >48 hours. Thus, weaning from the ventilator succeeded. We encouraged patients in the conventional group to cough and used the same decannulation criteria as with the dual-mode group.

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Statistical Analysis

Categorical variables were compared using the Fisher exact test (SPSS 17.0; SPSS, Chicago, IL). Normally distributed continuous variables were compared using the unpaired Student t test. Non-normally distributed continuous variables were compared using the Mann-Whitney U test.

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RESULTS

Thirty-two tracheotomy patients were enrolled in the present study and randomly allocated to either the dual-mode (n = 15) or conventional (n = 17) weaning group. At randomization, the patients in each group had similar characteristics (Tables 1 and 2). Of these 32 patients, 4 were directed to tracheotomy because of difficult intubation, 9 were directed to tracheotomy because of consideration of long-duration MV, and 19 were directed to tracheotomy because of difficult weaning from intubation. The tracheotomy tube size was 7.5 mm (internal diameter) for 31 patients and 7.0 mm for 1 dual-mode patient. One patient failed the first attempt at NIV because of discomfort with dual-mode weaning. However, we made another attempt 2 hours later, which succeeded with the encouragement and guidance of a respiratory therapist.

Table 1

Table 1

Table 2

Table 2

Patients in the dual-mode group underwent 3 complete alternations, and 14 patients were successfully weaned from MV. The duration of NIV in the first shift (from IMV to NIV) was 10 ± 11 days, and 12 patients were ventilator free. The duration of IMV in the second shift (from NIV to IMV) was 12 ± 8 days. This time, 2 patients successfully shifted to NIV but 1 died. In the third shift (from IMV to NIV), the duration of NIV was 10 ± 5 days, and 2 patients were ventilator free.

Compared with the conventional group, in the dual-mode group, the total duration of MV was reduced by a median of 21 days (P = 0.03), the total duration of IMV was reduced by 32 days (P < 0.01), and the total duration of the ICU stay was reduced by 28 days (P = 0.01) (Table 3). Patients in the dual-mode group had a higher rate of successful weaning (14 of 15 vs 10 of 17, P = 0.04), a lower mortality rate during weaning (1 of 15 vs 7 of 17, P = 0.04), and a lower rate of pulmonary infection after randomization (3 of 15 vs 12 of 17, P < 0.01) compared with patients in the conventional group (Table 3).

Table 3

Table 3

Rates of pneumonia, recurrence of pneumonia, and re-recurrence of pneumonia are summarized in Table 4. In the dual-mode group, pneumonia occurred in 12 patients and recurred in 5 patients. In the conventional group, pneumonia occurred in 16 patients, recurred in 13 patients, and re-recurred in 4 patients. After randomization, the dual-mode group had a lower recurrence of pneumonia (3 of 15 vs 12 of 17, P < 0.01) than the conventional group. Before discharge, 4 patients in the dual-mode group died (2 from heart attack, 1 from multidrug-resistant [MDR] bacterial pneumonia, and 1 from apnea), and 8 in the conventional group died (1 from heart attack, 5 from MDR bacterial pneumonia, and 2 from septicemia coupled with MDR bacterial pneumonia).

Table 4

Table 4

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DISCUSSION

Many studies have demonstrated that NIV is a successful strategy for weaning intubated patients from the ventilator. It dramatically reduces mortality, VAP, the duration of MV, and the duration of ICU and hospital stays.24,8,9 In these studies, in one group of patients, the tube was removed for NIV and in the other it remained in position with the cuff inflated and 2 ends of the tube open for invasive ventilation. This greatly benefitted patients in the NIV group. We used a similar strategy for dual-mode weaning. However, in our study, we kept the capped tracheotomy tube in the airway with the cuff deflated as a safe channel and then performed NIV. If the patient's status deteriorated, we uncapped the tube, inflated the cuff, and connected him or her to IMV. Therefore, the reintubation did not occur in dual-mode weaning. In our study, another difference was that we could use this channel to suction the airways of patients who were unable or too weak to cough. However, performing NIV on intubated patients with the tube removed may lead to failure because of complications (e.g., apnea) related to an inability to cough. Thus, the dual-mode weaning method reported herein not only has all of the advantages of NIV for facilitating weaning in intubated patients but also successfully avoids the complications of reintubation and enables safe and convenient suctioning of the airway in patients who are unable or too weak to cough. Thus, dual-mode weaning is safe and feasible for use in difficult-to-wean tracheotomy patients, and it is seemingly better than when NIV is used to facilitate weaning in the intubated patient.

In our study, nearly all patients were elderly with comorbidity (e.g., chronic obstructive pulmonary disease, diabetes mellitus, hypertension, coronary artery disease). These factors partly contribute to difficult weaning.10 Ventilator-induced diaphragmatic dysfunction occurred as early as 18 to 69 hours of complete controlled ventilation.11 The long duration of IMV weakened not only diaphragmatic functions but also other respiratory muscle functions, which subsequently led to difficult weaning. In these patients, respiratory muscle strength was low, neuromuscular drive was high, and the load capacity of the lungs was unbalanced, which contributed to the difficulty weaning.10,12 VAP is another cause of difficult weaning, because it significantly increases the duration of MV, the duration of ICU stay, and the mortality rate.13,14 The long duration of IMV led to weaker respiratory muscle function and a higher rate of VAP. If respiratory muscle function continuously weakens and VAP occurs, the duration of IMV and the mortality rate increase sharply. This vicious cycle exacerbates already difficult weaning. In our study, we tried our best to wean patients from MV according to general weaning management.7 Although most patients were easily weaned from MV, some were not (Fig. 1). After tracheotomy, 3 consecutive days of weaning attempts failed in all patients. This indicated that conventional weaning was ineffective. Given its benefits, we introduced NIV in these patients to stop the vicious cycle.

Patients in the dual-mode weaning group received many more benefits than patients in the conventional weaning group. First, dual-mode weaning had all of the advantages of NIV, which is used to facilitate weaning in intubated patients.24,8,9 During NIV, each breath was triggered and cycled by the patient himself or herself. NIV trains the respiratory muscles and maximally develops the patient's strength. However, in conventional weaning, the respiratory muscles continue to atrophy. This results in more difficult weaning, longer MV, and higher mortality (Tables 3 and 5, Figs. 3 and 4).

Table 5

Table 5

Figure 3

Figure 3

Figure 4

Figure 4

Second, the conventional weaning patients were similar to the intubated patients in that the upper airway was bypassed. Thus, the defensive function of the upper airway did not work, which significantly increased the risk of pneumonia. In addition, as the cuff was inflated during IMV support, secretions accumulated above the cuff, becoming a source of pneumonia.15 Although the incidence and recurrence of VAP before randomization were similar in both groups, it decreased in the dual-mode group after randomization (Table 4). In the conventional group, pneumonia recurred in 12 patients and, worse, re-recurred in 4 patients. The mortality rate of VAP ranges from 24% to 50% and can reach as high as 76% in some settings or when lung infection is caused by high-risk pathogens.16 Moreover, the recurrence of VAP or pneumonia further increased the mortality rate.17 When the pneumonia recurred after long-term MV, most of the bacteria were resistant to multiple drugs. This helped to increase the duration of MV and the mortality rate in the conventional group (Tables 3 and 5, Figs. 3 and 4).

Third, psychological factors also lead to difficult weaning, long duration of MV, and high mortality.1820 Patients received less ventilation support when they were shifted from IMV to NIV in the dual-mode group. In addition, dual-mode weaning reversed the weaning failures, which had repeatedly taken place before randomization. This increased the patients' confidence in becoming successfully weaned. Furthermore, patients could speak with their physicians and families when the mask was temporarily removed. This further increased their confidence and greatly encouraged them to overcome the disease. However, in the conventional group, weaning failures continued, and patients could not conveniently talk with their families or physicians because their upper airway was bypassed. This increased their depression and their fear of death, which dramatically increased the duration of MV and the mortality rate (Tables 3 and 5, Figs. 3 and 4).

Fourth, clinicians encouraged patients in the dual-mode group to cough through their mouths when clinical symptoms indicated sputum in the airway. This exercised patients' ability to cough. However, the inflated cuff in the conventional group made the training inconvenient, which may have delayed patients' recovery of the ability to cough.

A weak ability to cough and a large amount of sputum are contraindications of NIV.21,22 However, in our study, we successfully used NIV to treat patients with these conditions. We kept the tracheotomy tube in the airway so we could suction the sputum if necessary. If the patient's ability to cough improved and the amount of sputum decreased, we decreased the frequency of suctioning. When the patient recovered the ability to cough and the amount of sputum decreased, the tracheotomy tube was decannulated.23

The key to success lies in how one manages NIV at the beginning of dual-mode weaning. The presence of the tracheotomy tube in the airway may decrease the patient's tolerance of NIV. When we performed NIV in these patients, we took much more care than we do for NIV used in other patients. Even so, one patient failed to tolerate NIV on the first attempt because of discomfort. Thus, clinicians who perform NIV on these patients need more patience, effort, and experience.

The patients in the groups were not well matched (Tables 1 and 2). Although these differences were not statistically significant, given the small sample size, they may have skewed the outcomes. Thus, future clinical studies should include large randomized control samples to demonstrate the efficacy of dual-mode ventilation.

The switching point from IMV to NIV may be done earlier, even just after the tracheotomy, because the tracheotomy tube is in the airway as a safe channel. Because this was a feasibility study, the time between shifting from NIV to IMV or from IMV to NIV may have been too long. Future studies might consider reducing the shifting period.

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CONCLUSIONS

The success of this dual-mode weaning strategy is based not only on the efficacy of NIV but also on its ability to improve patients' mood and train patients to regain their ability to cough. Dual-mode weaning reduces the total duration of MV, total duration of IMV, total duration of ICU stay, mortality rate, and rate of pulmonary infection after randomization. In a small cohort of patients with tracheotomies, we demonstrated that dual-mode weaning reduced the total duration of MV and ICU stay; we recommend additional studies to assess its effect on pulmonary infections and mortality.

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DISCLOSURES

Name: Jun Duan, MD.

Contribution: This author helped design the study, conduct the study, analyze the data, and prepare the manuscript.

Name: Shuliang Guo, MD.

Contribution: This author helped manage the study, design the study, conduct the study, analyze the data, and prepare the manuscript.

Name: Xiaoli Han, MD.

Contribution: This author helped design the study.

Name: Xiaokui Tang, MD.

Contribution: This author helped design the study and conduct the study.

Name: Lulu Xu, MD.

Contribution: This author helped conduct the study.

Name: Xia Xu, MD.

Contribution: This author helped conduct the study.

Name: Yucun Liu, MD.

Contribution: This author helped conduct the study.

Name: Jinwei Jia, MD.

Contribution: This author helped conduct the study.

Name: Shicong Huang, MD.

Contribution: This author helped conduct the study.

Name: Yamei Wu, MD.

Contribution: This author helped design the study.

This manuscript was handled by: Michael Murray, MD, PhD.

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ACKNOWLEDGMENTS

We thank Dr. Youlun Li and Liangan Hu for their technical help.

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