Abstract
Introduction:
Endotracheal suctioning is a method commonly used to clean airway secretions in patients under mechanical ventilation (MV). This study aimed to compare the effects of open and closed suction methods on the occurrence of ventilator associated pneumonia (VAP).
Methods:
This comparative study was carried out on adult intensive care unit (ICU) patients in need of MV for more than 48 hours, from October 2018 to January 2019. Patients were randomly allocated to either closed tracheal suction system (CTSS) group or open tracheal suction system (OTSS) group. Patients were monitored for developing VAP within 72 hours of intubation and the findings were compared between groups.
Results:
120 cases with the mean age of 57.91±19.9 years were randomly divided into two groups (56.7% male). The two groups were similar regarding age (p = 0.492) and sex (p = 0.713) distribution. 22 (18.3%) cases developed VAP (12 (20%) in OSST group and 10 (16.7%) in CSST; p = 0.637). The most prevalent bacterial causes of VAP were Acinetobacter_Baumannii (72.7%), Klebsiella pneumoniae (18.2%), and Methicillin-Resistant Staphylococcus aureus (9.1%), respectively. There was not any significant difference between groups regarding the mean duration of remaining under MV (p = 0.623), mean duration of hospitalization (p = 0.219), frequency of VAP (p = 0.637), and mortality (p = 0.99).
Conclusion:
It seems that type of endotracheal suction system (OSST vs. CSST) had no effect on occurrence of VAP and other outcomes such as duration of need for MV and ICU stay as well as mortality.
Key Words: Pneumonia, Ventilator-Associated, Respiration, Artificial, critical care, intensive care units, suction
Introduction:
Ventilator-associated pneumonia (VAP) is one of the most common nosocomial infections in intensive care units (ICUs), and is associated with a high rate of morbidity and high cost of care (1). Therefore, any intervention to reduce VAP will result in reducing costs, morbidity and mortality (2). Endotracheal tube (ETT) suctioning is an essential procedure in patients undergoing mechanical ventilation (MV) with intubation to keeping the airways open through removal of accumulated pulmonary secretions (3). In addition, performing suction accurately is important to prevent VAP (4).
Two different methods are used for ETT suctioning, open tracheal suction system (OTSS), and closed tracheal suction system (CTSS). OTSS method requires participation of two nurses and may lead to temporary disruption of ventilation and oxygen supply due to disconnection of the patient from ventilation device during suctioning and the most important risk factor in this method is hypoxia (5, 6). However, in CTSS method, ETT suctioning can be administrated through connections in closed suction set and while the ventilation is being performed without disconnecting the patient from the ventilator (7). The effect of open and closed suction methods on preventing VAP is still an open field to be explored, because the results of previous studies are contradictory (8-12). Some studies showed that there was no difference between closed and open endotracheal suction systems in terms of VAP development (9, 11, 12). On the other hand, Alipour et al. (10) and Fakhar et al. (13) showed that closed suction is associated with a lower risk of VAP compared to open suction. Therefore, we conducted this comparative study to compare the effects of open and closed suction methods on VAP in mechanically ventilated patients.
Methods:
Study design and setting
This comparative study was conducted prospectively on ICU-admitted patients in Shohadaye Tajrish Hospital, Tehran, Iran, from October 2018 to January 2019. Patients were randomly divided into two groups of CTSS and OTSS and the outcomes (VAP occurrence, mortality, ICU stay, and duration of need to MV) of the two groups were compared. This study was performed after receiving approval from the ethics committee of Shahid Beheshti University of medical sciences (Ethics code: IR.SBMU.MSP.REC.1398.69). A written consent was obtained from patients or legal guardians of patients.
Participants
Adult patients who underwent MV for more than 48 hours were included in the study. Patients unwilling to participate or those with pneumonia or any other underlying respiratory diseases that increase the risk of pneumonia at the time of admission and patients who had remained intubated for more than 48 hours before admission were excluded from the study.
Data gathering
Demographic characteristics of patients (age and sex), duration of MV and the length of hospital stay as well as developing VAP within 72 hours of intubation were examined and recorded by an intensivist for all cases.
Procedure
Patients who met the inclusion criteria were randomly divided into two groups of CTSS and OTSS based on endotracheal suction methods using sequential randomization. In both groups, throat samples from endotracheal tubes and ventilator tubing were taken to determine the rate of colonization. Conventional bacteriological methods were used for identification of isolated micro-organisms. Antimicrobial susceptibility test was performed using Disk Diffusion method according to CLSI (Clinical and Laboratory Standards Institute) guidelines (14).
Suction methods were administrated based on the protocol of American Association for Respiratory Care (AARC) (15). Endotracheal suction was performed by experienced ICU nurses. In the OTSS group, suctioning was performed using single use catheters with full barrier measures (hand washing and use of gloves). Patients were pre-oxygenated for 2 minutes before suctioning. In the CTSS group, the system used for respiratory system suctioning was (Vital-Cath TM 72 Closed Suction Systems) and suction catheter was changed every 48 hours. Similar to the other group, patients were pre-oxygenated, and suctioning was performed without disconnection from the ventilator. The following VAP prophylaxis strategies were used in all patients: head elevation (30-40°), heat and moisture exchanger (HME) for humidification, protocolized sedation and enteral nutrition, performing suction only when necessary, avoiding routine change of the respiratory circuit unless necessary, mouth washing with chlorhexidine in each shift, pantoprazole for prophylaxis of stress ulcer, verification of gastric residual volume in each shift, avoidance of unnecessary extubation or intubation, maintenance of cuff pressure between 20-30 mmHg and continuous aspiration of subglottic secretions. All interventions were done by one medical doctor and two nurses who provided care for both groups.
Diagnosis of VAP was performed based on clinical pulmonary infection score (CPIS) (16). Patients were monitored for 72 hours from suctioning and examined by an infectious disease specialist. Bacterial pneumonia index calculated based on persistent infiltration in the chest X-ray, body temperature, white blood cell count, airway discharges, ratio of arterial blood oxygen to inhaled oxygen, and culture and smear of lung discharges were recorded. Patients were considered to have pneumonia if they received a score higher than 6 (appendix 1) (17).
Appendix 1.
Clinical Pulmonary Infection Score used for diagnosis of ventilator-associated pneumonia
| Criterion | Score |
|---|---|
| Temperature, °C | |
| ≥36.5 and ≤38.4 | 0 |
| 38.5 and ≤38.9 | 1 |
| ≥39 and ≤ 36 | 2 |
| Leukocyte count (1/mm 3 ) | |
| ≥4,000 and ≤11,000 | 0 |
| <4,000 or >11,000 | 1 |
| +band forms ≥500 | 2 |
| Oxygenation, PaO 2 /FiO 2 (mmHg) | |
| >240 or ARDS | 0 |
| ≤240 and no evidence of ARDS | 2 |
| Pulmonary radiography | |
| No infiltrate | 0 |
| Diffused (or patchy) infiltrate | 1 |
| Localized infiltrate | 2 |
| Tracheal secretions | |
| <14+ | 0 |
| ≥14+ | 1 |
| + purulent secretion | 2 |
| Culture of tracheal aspirate* | |
| Pathogenic bacteria cultured ≤1+ or no growth | 0 |
| Pathogenic bacteria cultured >1+ | 1 |
| + same pathogenic bacteria seen on the Gram stain >1+ | 2 |
*: Semi-quantitative: 0-1-2 or 3+. ARDS: Acute respiratory distress syndrome.
Statistical analysis
Qualitative variables were reported as percentage and quantitative variables as mean± standard deviation. We used Student t test and chi-square test for detection of differences between the two groups. Fisher’s exact test was used for qualitative analysis when necessary. For analyzing data, SPSS version 21 (SPSS Inc., IMB Corporation, Chicago, Illinois, USA) was used. P value equal to or less than 0.05 was considered statistically significant.
Results:
120 cases with the mean age of 57.91±19.9 (17 – 94) years were randomly divided into two groups of OSST or CSST (56.7% male) with equal participants. The two groups were similar regarding age (p = 0.492) and sex (p = 0.713) distribution. 22 (18.3%) cases developed VAP (12 (20%) in OSST group and 10 (16.7%) in CSST; p = 0.637). The most prevalent bacterial causes of VAP were Acinetobacter_Baumannii (72.7%), Klebsiella pneumoniae (18.2%), and Methicillin-Resistant Staphylococcus aureus (9.1%), respectively. No statistically significant difference was detected between groups regarding the frequency of bacterial causes VAP (p = 1.000). Table 1 compares the outcomes of patients between groups. There was not any significant difference between groups regarding the mean duration of undergoing MV (p = 0.623), mean duration of hospitalization (p = 0.219), frequency of VAP (p = 0.637), and mortality (p = 0.99).
Table 1.
Comparing the outcomes between open tracheal suction system (OTSS) and closed tracheal suction system (CTSS) groups
| Outcomes |
Type of suction
|
p | |
|---|---|---|---|
| OTSS (n=60) | CTSS (n=60) | ||
| Ventilator associated pneumonia | |||
| Yes | 12 (20.0) | 10 (16.7) | 0.637 |
| No | 48 (80.0) | 50 (83.3) | |
| Duration of ventilation | |||
| Mean ± SD | 13.47±10.83 | 12.62±7.82 | 0.623 |
| Range (days) | 5-65 | 5-47 | |
| Hospitalization days | |||
| Mean ± SD | 21.83±12.72 | 19.20±10.50 | 0.219 |
| Range (days) | 8-73 | 8-55 | |
| Microorganism | |||
| Acinetobacter_Baumannii | 9 (56.2) | 7 (43.8) | 0.96 |
| Klebsiella pneumoniae | 2 (50.0) | 2 (50.0) | |
| MRSA | 1 (50.0) | 1 (50.0) | |
| No | 48 (49.0) | 50 (51.0) | |
| Death | |||
| Yes | 39 (65.0) | 39 (65.0) | 0.99 |
| No | 21 (35.0) | 21 (35.0) | |
Data are presented as mean ± standard deviation (SD) or frequency (%). MRSA: Methicillin-resistant Staphylococcus aureus.
Discussion:
The results revealed that the type of endotracheal suction system (OSST vs. CSST) had no effect on development of VAP and ICU outcome. In addition, our results did not show any significant difference between the two groups regarding length of ICU stay and duration of MV and mortality rate, which is similar to the results of Combes et al. (18), Topeli et al. (12), Ozcan et al. (19) and Hamishekar et al. (9).
Different studies that assessed the effect of open and closed suction on incidence of VAP showed controversial findings (9, 10, 12). Our finding is consistent with some previous studies that showed no statistically significant difference between OSST and CSST endotracheal suctioning systems in terms of VAP development (20, 21). In a systematic review by Subirana et al., 16 clinical trials were assessed; their results showed that using open or closed suction methods had no effect on VAP (22). A prospective randomized study, which was carried out on 100 patients in surgical ICU by Hamishekar et al. to evaluate the effect of CTSS versus OTSS did not show any statistically significant effect on VAP incidence in multivariate analysis (9). However, in contrast to our findings, some studies showed that closed suction method has superiority over open method in reducing the incidence of VAP (10, 13). In a prospective clinical trial performed by David et al. clinical results of OSST and CSST were assessed in 200 patients under MV in India; they found that using closed suction reduced the incidence of VAP. However, mortality rate and hospital stay in ICU were the same in both groups (23). The controversial/contradicting results in different studies can have many reasons such as small sample size, inappropriate inclusion or exclusion criteria such as including patients with underlying respiratory diseases, short duration of study period, not teaching the principles of using closed suction to nurses, and not using the VAP prophylaxis strategies in open suction method.
In the present study, we tried to solve the above-mentioned limitations by using appropriate inclusion and exclusion criteria, including appropriate number of patients in both groups, properly training nurses for using closed suction, and using VAP prophylaxis strategies as a health principle. Considering that both endotracheal suction systems have advantages and disadvantages, it seems that the incidence of VAP can be reduced by using aseptic precautions based on signs and symptoms, as well as the correct use of guidelines in both suction systems.
The distribution of micro-organisms causing VAP was different in various studies, which could be due to differences in patient demographics, methods of diagnosis, duration of hospitalization, ICU stays, and antibiotic policy (24, 25). In the present study, Acinetobacter_Baumannii was the most common isolated pathogen (72.7%) in patients with VAP followed by Klebsiella pneumoniae (18.2%) and methicillin-resistant Staphylococcus aureus (MRSA) (9.1%). Consistent with the present investigation, a study by Dey et al. reported Acinetobacter species (48.94%) as the most common isolate from early-onset and late-onset VAP (26). Previous studies have shown that Acinetobacter species ranked fifth among the causative organisms of VAP (27-29). Bozorgmehr et al. reported that acinetobacter baumannii and klebsiella pneumoniae were the most common germs growing in sputum cultures and most of them were pan drug resistance (PDR) or extensive drug resistance (XDR) (30).
Our study limitation is that type of VAP (early or delayed) was not studied, which is suggested to be further evaluated in future studies. In addition, data regarding underlying diseases and cause of intubation were not recorded; however, they may play a role in increasing mortality due to ventilation.
In conclusion, according to the findings of this study, the use of CSST has no superiority over OSST in reducing VAP incidence of and it has no effect on ICU outcome. The incidence of VAP was remarkable in both groups, which led to an increase in hospitalization and mechanical ventilation in these patients. In addition, Acinetobacter_Baumannii was found to be the most common isolated pathogen followed by K. pneumoniae and MRSA.
Conclusion:
It seems that type of endotracheal suctioning system (OSST vs. CSST) had no effect on occurrence of VAP and other outcomes such as duration of MV and ICU stay as well as mortality.
Acknowledgment
Hereby, we thank the ICU staff members of Shohadaye Tajrish Hospital for their hearty cooperation and helping us perform this study.
Author contribution
All the authors met the 4 criteria recommended by the international committee of medical journal editors for gaining authorship.
Funding and support
None.
Conflict of interest
All authors declare that they have no conflict of interest.
References
- 1.Charles MP, Kali A, Easow JM, Joseph NM, Ravishankar M, Srinivasan S, et al. Ventilator-associated pneumonia. The Australasian medical journal. 2014;7(8):334–44. doi: 10.4066/AMJ.2014.2105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Keyt H, Faverio P, Restrepo MI. Prevention of ventilator-associated pneumonia in the intensive care unit: a review of the clinically relevant recent advancements. The Indian journal of medical research. 2014;139(6):814–21. [PMC free article] [PubMed] [Google Scholar]
- 3.Liu XW, Jin Y, Ma T, Qu B, Liu Z. Differential Effects of Endotracheal Suctioning on Gas Exchanges in Patients with Acute Respiratory Failure under Pressure-Controlled and Volume-Controlled Ventilation. BioMed research international. 2015;2015:941081. doi: 10.1155/2015/941081. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Vijai MN, Ravi PR, Setlur R, Vardhan H. Efficacy of intermittent sub-glottic suctioning in prevention of ventilator-associated pneumonia- A preliminary study of 100 patients. Indian journal of anaesthesia. 2016;60(5):319–24. doi: 10.4103/0019-5049.181592. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Sarkar M, Niranjan N, Banyal PK. Mechanisms of hypoxemia. Lung India : official organ of Indian Chest Society. 2017;34(1):47–60. doi: 10.4103/0970-2113.197116. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Lasocki S, Lu Q, Sartorius A, Fouillat D, Remerand F, Rouby JJ. Open and closed-circuit endotracheal suctioning in acute lung injury: efficiency and effects on gas exchange. Anesthesiology. 2006;104(1):39–47. doi: 10.1097/00000542-200601000-00008. [DOI] [PubMed] [Google Scholar]
- 7.Siempos II, Vardakas KZ, Falagas ME. Closed tracheal suction systems for prevention of ventilator-associated pneumonia. British journal of anaesthesia. 2008;100(3):299–306. doi: 10.1093/bja/aem403. [DOI] [PubMed] [Google Scholar]
- 8.Kuriyama A, Umakoshi N, Fujinaga J, Takada T. Impact of closed versus open tracheal suctioning systems for mechanically ventilated adults: a systematic review and meta-analysis. Intensive care medicine. 2015;41(3):402–11. doi: 10.1007/s00134-014-3565-4. [DOI] [PubMed] [Google Scholar]
- 9.Hamishekar H, Shadvar K, Taghizadeh M, Golzari SE, Mojtahedzadeh M, Soleimanpour H, et al. Ventilator-associated pneumonia in patients admitted to intensive care units, using open or closed endotracheal suctioning. Anesthesiology and pain medicine. 2014;4(5):e21649. doi: 10.5812/aapm.21649. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Aliopur N, Toulabi T, Manouchehrian N, Anbari KH, Rahimi Bashar F. A comparison the effect of open and close endotracheal suctioning on hemodynamic status of patient with head trauma hospitalized in intensive care unit. EVIDENCE BASED CARE. 2014;3(4):65–73. [Google Scholar]
- 11.Afshari A, Safari M, Oshvandi K, Soltanian AR. The effect of the open and closed system suctions on cardiopulmonary parameters: time and costs in patients under mechanical ventilation. Nursing and midwifery studies. 2014;3(2):e14097. [PMC free article] [PubMed] [Google Scholar]
- 12.Topeli A, Harmanci A, Cetinkaya Y, Akdeniz S, Unal S. Comparison of the effect of closed versus open endotracheal suction systems on the development of ventilator-associated pneumonia. The Journal of hospital infection. 2004;58(1):14–9. doi: 10.1016/j.jhin.2004.05.005. [DOI] [PubMed] [Google Scholar]
- 13.Ebrahimi fakhar H, Rezaei K, Kohestani H. Closed suction effect of pulmonary secretions of Ventilator-associated Pneumonia. Scientific Journal of Kurdistan University of Medical Sciences. 2010;15(2):79–87. [Google Scholar]
- 14.Kassim A, Omuse G, Premji Z, Revathi G. Comparison of Clinical Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing guidelines for the interpretation of antibiotic susceptibility at a University teaching hospital in Nairobi, Kenya: a cross-sectional study. Annals of clinical microbiology and antimicrobials. 2016;15:21. doi: 10.1186/s12941-016-0135-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.AARC Clinical Practice Guidelines. Endotracheal suctioning of mechanically ventilated patients with artificial airways 2010. Respiratory care. 2010;55(6):758–64. [PubMed] [Google Scholar]
- 16.Schurink CAM, Nieuwenhoven CAV, Jacobs JA, Rozenberg-Arska M, Joore HCA, Buskens E, et al. Clinical pulmonary infection score for ventilator-associated pneumonia: accuracy and inter-observer variability. Intensive care medicine. 2004;30(2):217–24. doi: 10.1007/s00134-003-2018-2. [DOI] [PubMed] [Google Scholar]
- 17.Pugin J, Auckenthaler R, Mili N, Janssens JP, Lew PD, Suter PM. Diagnosis of ventilator-associated pneumonia by bacteriologic analysis of bronchoscopic and nonbronchoscopic “blind” bronchoalveolar lavage fluid. Am Rev Respir Dis. 1991;143:1121–9. doi: 10.1164/ajrccm/143.5_Pt_1.1121. [DOI] [PubMed] [Google Scholar]
- 18.Combes P, Fauvage B, Oleyer C. Nosocomial pneumonia in mechanically ventilated patients, a prospective randomised evaluation of the Stericath closed suctioning system. Intensive care medicine. 2000;26(7):878–82. doi: 10.1007/s001340051276. [DOI] [PubMed] [Google Scholar]
- 19.Ozcan MS, Bonett SW, Martin AD, Gabrielli A, Layon AJ, Banner MJ. Abnormally increased power of breathing as a complication of closed endotracheal suction catheter systems. Respiratory care. 2006;51(4):423–5. [PMC free article] [PubMed] [Google Scholar]
- 20.Jongerden IP, Buiting AG, Leverstein-van Hall MA, Speelberg B, Zeidler S, Kesecioglu J, et al. Effect of open and closed endotracheal suctioning on cross-transmission with Gram-negative bacteria: a prospective crossover study. Critical care medicine. 2011;39(6):1313–21. doi: 10.1097/CCM.0b013e3182120815. [DOI] [PubMed] [Google Scholar]
- 21.Morrow BM, Mowzer R, Pitcher R, Argent AC. Investigation into the effect of closed-system suctioning on the frequency of pediatric ventilator-associated pneumonia in a developing country. Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies. 2012;13(1):e25–32. doi: 10.1097/PCC.0b013e31820ac0a2. [DOI] [PubMed] [Google Scholar]
- 22.Subirana M, Sola I, Benito S. Closed tracheal suction systems versus open tracheal suction systems for mechanically ventilated adult patients. The Cochrane database of systematic reviews. 2007(4):Cd004581. doi: 10.1002/14651858.CD004581.pub2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.David D, Samuel P, David T, Keshava SN, Irodi A, Peter JV. An open-labelled randomized controlled trial comparing costs and clinical outcomes of open endotracheal suctioning with closed endotracheal suctioning in mechanically ventilated medical intensive care patients. Journal of critical care. 2011;26(5):482–8. doi: 10.1016/j.jcrc.2010.10.002. [DOI] [PubMed] [Google Scholar]
- 24.Liu Q, Yang J, Zhang J, Zhao F, Feng X, Wang X, et al. Description of Clinical Characteristics of VAP Patients in MIMIC Database. Frontiers in pharmacology. 2019;10:62. doi: 10.3389/fphar.2019.00062. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Chin T, Kushner B. Antibiotic Utilization Patterns in Patients with Ventilator-Associated Pneumonia. A Canadian Context. 2016;2016:3702625. doi: 10.1155/2016/3702625. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Dey A, Bairy I. Incidence of multidrug-resistant organisms causing ventilator-associated pneumonia in a tertiary care hospital: a nine months' prospective study. Annals of thoracic medicine. 2007;2(2):52–7. doi: 10.4103/1817-1737.32230. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Giamarellou H, Antoniadou A, Kanellakopoulou K. Acinetobacter baumannii: a universal threat to public health? International journal of antimicrobial agents. 2008;32(2):106–19. doi: 10.1016/j.ijantimicag.2008.02.013. [DOI] [PubMed] [Google Scholar]
- 28.Joly-Guillou ML. Clinical impact and pathogenicity of Acinetobacter. Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases. 2005;11(11):868–73. doi: 10.1111/j.1469-0691.2005.01227.x. [DOI] [PubMed] [Google Scholar]
- 29.Peleg AY, Seifert H, Paterson DL. Acinetobacter baumannii: emergence of a successful pathogen. Clinical microbiology reviews. 2008;21(3):538–82. doi: 10.1128/CMR.00058-07. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Bozorgmehr R, Bahrani V, Fatemi A. Ventilator-Associated Pneumonia and Its Responsible Germs; an Epidemiological Study. Emergency (Tehran, Iran) 2017;5(1):e26. [PMC free article] [PubMed] [Google Scholar]