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| ORIGINAL ARTICLE |
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| Year : 2017 | Volume
: 22
| Issue : 1 | Page : 12-17 |
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A retrospective study of endotracheal or tracheostomy tube blockage and their impact on the patients in an intensive care unit
Habib Md. Reazaul Karim, Md. Yunus, Prithwis Bhattacharyya
Department of Anaesthesiology and Critical Care, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong, Meghalaya, India
| Date of Web Publication | 14-Mar-2017 |
Correspondence Address:
Md. Yunus
B-10C, Faculty Quarters, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences Campus, Shillong - 793 018, Meghalaya
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0971-9903.202013
Background: Endotracheal and tracheostomy tube (TT) blockage is a common airway accident in Intensive Care Unit (ICU). Although tube blockage is rarely fatal, it has a major impact on the quality of ICU care and the family of the patient. The present study is aimed to assess the tube accidents; primarily, the number, timing, the cause of tube blockage in intubated patients and its impact along with the risk of blockage in relation to respiratory diseases, demography, and on-tube duration. Materials and Methods: After the Ethical Committee approval, the study was conducted in a mixed ICU. Data were collected retrospectively from the ICU assessment record of patients admitted from November 2012 to October 2014. The total numbers of intubated patients and the duration of intubation were recorded. Patients who were intubated for >24 h were evaluated for risk analysis. Data were analyzed using InStat software with Fisher's exact test and unpaired t-test. Results: There were 105 episodes of tube blockage in 72 out of 975 intubated patients during 3797 tube days resulting in five cardiac arrests and one death. Endotracheal tube tubes tend to get blocked earlier than TT tubes (6.30 vs. 8.09 days). The risk of tube blockage increases significantly in patients having ventilator-associated pneumonia (VAP) and who have been intubated for 5 days or more (P < 0.0001). Conclusions: Fatality from tube blockage is rare but causes preventable death. Hence, tube change for ongoing airway management between 5 and 7 days is probably justifiable, especially in patients with VAP. Keywords: Critical care, endotracheal tube blockage, fatality, tracheostomy tube blockage, tube accidents
How to cite this article:
Karim HM, Yunus M, Bhattacharyya P. A retrospective study of endotracheal or tracheostomy tube blockage and their impact on the patients in an intensive care unit. J Mahatma Gandhi Inst Med Sci 2017;22:12-7 |
How to cite this URL:
Karim HM, Yunus M, Bhattacharyya P. A retrospective study of endotracheal or tracheostomy tube blockage and their impact on the patients in an intensive care unit. J Mahatma Gandhi Inst Med Sci [serial online] 2017 [cited 2023 Mar 30];22:12-7. Available from: https://www.jmgims.co.in/text.asp?2017/22/1/12/202013 |
| Introduction | |  |
Intubation and ventilation in Intensive Care Unit (ICU) are needed for a number of reasons. Patients often need to be discharged to either recovery wards or to their homes along with tracheostomy tube (TT). Endotracheal tube (ET) or TT blockage is a common airway accident in ICU.[1] It usually occurs due to a large plug of inspissated mucus or a piece of crusted secretion and presents as an airway emergency. Their presence is often vague and nonspecific in ICU settings, where patient's disease condition itself shares same signs and symptoms many times. Although the majority of blockage is partial and can be detected early, sudden, and/or unnoticed progressive, and complete blockage can lead to cardiac arrest and death of the patient. There are multiple risk factors in ICU for tube blockage. Surveys suggest that there is significantly more that could be done to manage latent risk and achieve institutional preparedness, much of which is inexpensive and easy to implement.[2] Implementation of preventive measures can probably prevent unwanted deaths.
| Materials and Methods | | |
After the Institute Ethical Committee approval, the present study was conducted retrospectively in a mixed (both medical and surgical) ICU of mostly adult age group. The ICU is 31 bedded with a bed to working ventilator ratio 1:0.8 and staff nurse to patient ratio of 1:3–1:5/shift. The ICU assessment record charts along with doctors and nurses notes of the patients admitted between November 2012 and October 2014 were evaluated for data collection and assessment of the problem. All patients who had been admitted during the period were included in the study. Patients on either ET and/or TT for >24 h and <24 h were noted separately, and total number of ventilated days and intubated days were calculated. Details of age, sex, number of ventilated days, intubated days, day of tube blockage, primary organ system involved, and subsequent development of ventilator-associated pneumonia (VAP – defined as pneumonia occurring in a patient within 48 h or more after intubation with an ET or TT and which was not present before) during ICU stay were noted only in patients who were intubated for >24 h and were analyzed for tube blockage risk [Flow Diagram 1]. Adverse event notes in the charts were reviewed, and the reason of tube change, as well as accidental and self-extubation and their causes, were also noted. Tube changed following accidental extubation/self-extubation was not taken into account for tube blockage. Bradycardia (heart rate falling below 60 beats/min), desaturation (oxyhemoglobin saturation fall below 92% in patients having >98% previous reading), hypercapnia (partial pressure of arterial carbon dioxide >45 mmHg in patients whose 6–8 h previous reading was <40 mmHg), and cardiac arrest episodes attributable to the endotracheal or TT blockage only, mentioned in either of the nursing records or resident's note were noted as tube blockage impact for this study. If no reason/causes were clear from the file, it was counted as not mentioned. Our primary objective was to determine the number, timing, and the cause of tube blockage in intubated patients and its impact on the patient.
Data were analyzed using InStat software (GraphPad Software, Inc., La Jolla, CA. USA) with Fisher's exact test and unpaired t-test for risk of tube blockage and its statistical significance in relation to respiratory diseases, age, sex, and intubated days, whose results are summarized in [Table 1] and [Table 2]. Based on the findings of this study, we planned to formulate a quality care plan for future. Graphs are prepared using GraphPad Prism 5 software (GraphPad Software, Inc., La Jolla, CA. USA). | Table 1: Tube days and duration before tube blockage parameter expressed in number, percentage scale, and analyzed using unpaired t-test
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 | Table 2: Parameters related to tube accidents, its causes and impact expressed in percentage and per 100 tube days
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As most of the tube blockage occurs due to inspissated secretions, and respiratory diseases such as community-acquired pneumonia (CAP), healthcare-associated pneumonia (HCAP), and chronic obstructive pulmonary disease (COPD) are associated with increased tracheobronchial secretions/sputum production, the present study also evaluated their association with tube blockage as compared to nonrespiratory patients by calculating odds ratio (OR). CAP is defined here as pneumonia acquired outside a hospital or long-term care facility and HCAP as pneumonia in patients, who has been hospitalized within 90 days of the infection, resided in a nursing home or long-term care facility or received parenteral antimicrobial therapy, chemotherapy, or wound care within 30 days of pneumonia.
Brief on-tube patient management
Patients were usually intubated orotracheally using polyvinyl ET except few ears, nose, and throat (ENT) postoperative cases where oral surgery was done. Tubes were fixed with adhesive and were checked regularly and changed as required whenever adhesive tape was found to be peeling out of the skin. Tracheostomy was usually done between 5th and 7th ICU day for expected long-term ventilation patients except for a few postoperative and trauma patients who were tracheotomized from very 1st day. Galileo Gold (Hamilton Medical, Switzerland) and Puritan Bennett 840 (Covidien) ventilators were used for ventilation. More than 90% time, the ventilation mode was synchronized intermittent mandatory ventilation (SIMV) and pressure-SIMV and <10% assist – control, adaptive support ventilation, and airway pressure release ventilation. Heat and moisture exchanger (HME) filter was used in almost all patients. Patients were weaned off from ventilator alternately by reducing mandatory breaths and pressure support (PS) by a measure of two. Spontaneous breathing trial (SBT) was initiated when PS 8 cmH2O, mandatory breaths 8/min, FiO2 <50%, positive end-expiratory pressure 5–6 cmH2O, P/F >200, rapid shallow breathing index <105, hemodynamically stable, and other condition fulfilled as per our ICU protocol. If the patient passed through SBT, they were put on T-piece trial, and extubation was done if the patient tolerated it for 2 h along with fulfillment of extubation criteria. Analgesia and sedation were provided usually by injection butorphanol or morphine and injection lorazepam as required. Infusion of injection dexmedetomidine, midazolam, and propofol was used when continuous and relatively long period sedation was required. Sedation was monitored by Richmond Agitation-Sedation Scale. Violent/dangerously agitated patients were also restrained using soft roller bandage around the wrists with restricted range of movement. Approximately, 5–6 staff nurses looked after the patients per shift with a nurse to patient ratio of 1:3–5. Ward attendants provided bed care, diaper change, and positioning under the instruction of staff nurse. Endotracheal or TT suctioning was done whenever visible secretions were seen in tube, gurgling sound on coughing in patients on T-piece or room air or suspected to have secretions with high-respiratory rate, and peak airway pressure with obstructive pattern of breathing. Normal saline and injection mesna were rarely used before physiotherapy and suctioning in patients having very thick secretions only.
| Results | | |
A total of 975 intubated patients (mean standard deviation 46.32 [18.21] years of age; 515 medical and 460 surgical patients) were evaluated for the study. Tube days and duration before tube blockage parameter with regard to different tubes are shown in [Table 1]. The cause of tube blockage was mostly because of inspissated secretions (92.15%), followed by blood clotting (7.85%) among the noted cases [Table 2]. Although the exact number of partial and complete blockage could not be figured out because of incomplete data (51%) entry; it was noted that the number of partial/near complete blockage cases were more than those of complete blockage (92.8 vs. 7.2%) among the mentioned cases. Complete blockages were predominantly because of blood clot (80%) and two out of five episodes (40%) occurred in postoperative head and neck surgery.
Out of 161 tube-related accidents noted, there were 105 (65.2%) episodes of tube blockage in 72 out of 975 intubated patients during 3797 tube days (2.76/100 TDS). However, As the chance of tube blockage on the very 1st day is very rare, and there was no such case in the present study; hence, excluding the 431 patients who had been intubated for <24 h, the calculated true risk of tube blockage in 544 patients who were on tube for 3366 days comes 3.1/100 days. Twenty-one (29.17%) patients had two to four episodes of tube blockage during and such repeated episodes of tube blockage were because of inspissated secretions during their ongoing on-tube airway management ranging up to 69 days. Hypoxia and hypercapnia were the predominant impact (67.9%), and there were five cardiac arrests (0.13/100 TDS) from inspissated secretions and blood clot resulting in one death (0.026/100 TDS) [Table 3]. One more episode of cardiac arrest was noted during prone position ventilation which appeared to be due to profuse secretion blocking the tube, but the malposition of tube could not be ruled out. The mean duration before tube blockage was 7. 23 days. ET tubes often got blocked earlier than TT tubes (6.30 vs. 8.09 days), and the difference was statistically significant (P = 0.0002) [Figure 1]. Although older age group (>65 years) had relatively more tube blockage ratio, age, and sex did not appear to have an impact on the risk of tube blockage (P > 0.05). The risk of tube blockage increased significantly in patients intubated for 5 days or more (P < 0.0001). Respiratory diseases such as VAP were found to be associated with statistically significant risk of tube blockage (OR = 32.46, P < 0.0001). CAP, HCAP, and COPD were not associated with increased risk (OR < 1). ENT surgery was also not associated with increased risk (OR = 0.31) [Table 4]. | Table 3: Adverse impacts of tube blockage expressed in percentage and per 100 tube days
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 | Figure 1: Vertical scatter dot graph of endotracheal tube and tracheostomy tube block days showing mean with 95% confidence interval analyzed with unpaired t-test
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 | Table 4: Probable risk factors for tube blockage analyzed and results of Fisher's exact test
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| Discussion | | |
Tube blockage is a frequently encountered problem in patients on ET and TT which is typically manifested by either high airway pressures or inability to pass a suctioning catheter. However, high airway pressure may be because of poor compliance due to many causes in critical care patients. Frequent TT occlusion is a result of inspissated secretions.[3] A second common cause of TT occlusion is tube malpositioning such that the end of TT abuts the tracheal wall, or the tube has migrated such that its tip resides in the pretracheal tissues.[3] If tracheostomy malpositioning is suspected, the operating surgeon should assist in assessing it for either reinsertion or use of another tube design.
In an epidemiological study by Kapadia et al. has found 26 airway accidents in 5043 endotracheally intubated patients during 8446 patient ET days.[4] There were 10 tracheostomy-related accidents from a total of 79 patients with tracheostomies during 843 tracheostomy patient days; 6 had severe consequences, and 1 resulted in death. They have found that 11 were completely preventable, 17 partly preventable, and 8 were considered unpreventable.
It is evident that fatalities from airway accidents are rare in ICU, but many a time, it is preventable. Therefore, it has a great clinical significance. Although it is a well-perceived fact that the chance of tube blockage increase with the increasing duration on tube, there is relative paucity of the study to quantify and show the relation of tube blockage with tube days. Suspicion of blockage depends largely on expertise, experience, and knowledge of the staff. Therefore, the practice is widely variable and not completely free of hazard. Although routine changes for ongoing airway management and prevention of infection is mentioned as one of the indications for TT change and it is suggested that a TT should be changed every 7–14 days after initial insertion; it is not supported by good evidence.[5] Guidelines for prevention and management of VAP, HCAP does not recommend routine change of ventilator circuits and closed tracheal suctioning systems.[6],[7],[8],[9] However, these guidelines have not reviewed the routine change of TTs or ETs.[6],[7],[8],[9] Therefore, the practice of changing tubes in every 7–14 days for ongoing airway managements is still mostly based on the consensus recommendations.[5],[10] The present study has tried to quantify the risk of tube blockage so that the physician can take a conscious decision on-tube change in ICU.
The present analysis echoes with Aparna et al. finding of tube blockage, stating that the most common airway accidents in ICU were followed by unplanned extubation, but the tube blockage incidence was found to be higher in our analysis (2.76/100 TDS) as compared to their study (2.15/100 TDS).[1] Tube blockage incidence in the present study is also much higher than reported by Kapadia et al. (0.14/100 TDS) and in a meta-analysis (0.13/100 TDS).[11],[12] Such high incidence may be due to the fact that the average intubated days in our ICU patients were 3.89 days which was far higher than the average days (1.8) in the previous study.[11] Moreover, we have included a few partial blockage cases in patients where tubes have been changed on clinical suspicion and found to be blocked.
Observation also showed that many of the tubes were lined internally by encrusted secretions. Inadequate humidification of dry gas may be attributable to this which is also regarded as a modifiable risk factor.[13],[14],[15] Heated humidifier use may be associated with less tube blockage as compared to HME.[16],[17],[18] However, it is not supported by studies like Hurni et al. and Branson et al.[19],[20] The current study is unable to assess the risk with HME filter use/nonuse as almost all patients were on HME filter, which was changed regularly. The use of heated humidifier was negligible in the present study patients. Other factors that may lead to an increased incidence of airway accidents appears to be nurse-patient ratio,[1],[15] knowledge levels of the staff, time of accidents,[21] effect of weaning, head and neck surgery, and absence of dedicated team.[22],[23]
Nurse to ventilated patient ratio appears to be a major risk factor for tube blockage. Kapadia et al. noted 9 tracheal tube block in 6339 intubated days (0.14/100 TDS) in their study where they had 1:1 nurse to ventilated patient ratio and overall 1:1.4–1:1.8 nurse patient ratio.[11] Nurse patient ratio is also observed to be a risk for airway accidents in ICU by other studies.[1],[4] In the present ICU, nurse-patient ratio was 1:3–5 which is far lower than the mentioned study.[11] On the other hand, the incidence of tube blockage was far higher in the present study. This high incidence of tube blockage is probably partly contributed by low nurse-patient ratio which implies that low nurse-patient ratio is a risk for tube-related accidents.
de Mestral et al. have shown a reduction of tracheostomy tube blockage up to 5% from 25% as an impact of specialized TT care team while Norwood et al. have noted no death against two deaths in preservice group.[22],[23] The incidence of cardiac arrest following tube blockage is rare while death is far rarer. One prospective study has noted four cardiac arrests due to tube blockage in 6339 intubated days (0.06/100 TDS) while another meta-analysis has shown one death in 22,712 intubated days.[11],[12] In the present study, there were five cardiac arrests and one death. The cardiac arrest episode which leads to death occurred in the ward 1 day after shifting the patient from ICU due to tube blockage, and thus, the patient was shifted back to ICU. The tube was changed immediately on entering ICU which showed complete blockage with blood clot, but the patient could not be revived. Although what led to the bleeding was not evident, it appears that the death could have been prevented if blockage would have been suspected and changed slight early. This was probably because of the staff's inadequate knowledge to suspect tube blockage or lack of expertise in changing the tube.
Current findings in tube blockage with regard to the number of tube days are consistent with Khan et al., where they have noted significantly increased blockage of ETs with the duration of intubation.[24] They observed that tube blockage occurred once in patients who remained intubated for 0–7 days, and twice in patients who remained intubated for 8–14 days. In the present study, tube blockage risk increased significantly as the tube days increased beyond 5 days.
Tube blockage was more common in medical patients (12.03%) as compared to surgical patients (2.17%) which are consistent with finding as Kapadia et al.[25] This is probably because medical patients were on tube for prolonged days as compared to surgical patients. However, blockage was more common in TT patients (55 episodes in 991 days of >24 h on tube) as compared to ET patients (50 episodes in 2375 days of >24 h on tube) which are in contrast to Kapadia et al. findings.[25] This also appears to be because of high-tube days in TT group (13.75 vs. 4.36 days).
In the present study, only VAP is found to be a risk factor among the respiratory diseases evaluated. This finding is confounded with increase number of on-tube days as VAP were common in patients who were also on tube for more than 5–7 days. However, considering the very high OR 32.46 and extremely significant P < 0.0001, it appears to be a strong risk for endotracheal/TT blockage. The present study also gave a contradicting result of showing ENT patients as not on risk group (OR = 0.31) as previously thought.[3]
Two (33.33%) out of total six cardiac arrests noted during the study period were clearly preventable and rest four were also probably can be prevented if close monitoring of patients vital signs, ventilators' functionality, early recognition of deranged vital signs/changes of the ventilators settings, and prompt interventions were practiced more precisely with availability of more workforce.
The present study is limited with the fact that it is a retrospective study and degree of hypoxia and hypercapnia was not exactly measured due to relative incomplete data.
| Conclusions | | |
Continuous vigilance and adequate knowledge of the medical team with strong sense of pinpointing hazards are an indispensable part of care for early detection of tube blockage. Although fatality from tube blockage is rare, timely measures to tackle such incidents may avert such preventable deaths. Physicians should be extra alert as the on-tube duration exceeds 5–7 days to suspect tube blockage. “When in doubt, take it out” is usually followed by all anesthesiologist and intensivist, but change of tubes for ongoing airway management between 5 and 7 days especially in patients with VAP appears justifiable. Further study will be required to come to a strong conclusion and evidence-based recommendation.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1]
[Table 1], [Table 2], [Table 3], [Table 4]
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