Changes in lung volume with three systems of endotracheal suctioning with and without pre-oxygenation in patients with mild-to-moderate lung failure

Comparison of the effects of open and closed aspiration on end-expiratory lung volume in acute respiratory distress syndrome

BACKGROUND

Alveoli tend to collapse in patients with acute respiratory distress syndrome (ARDS). Endotracheal aspiration may increase alveolar collapse due to the loss of end-expiratory lung volume (EELV). We aimed to compare the loss of EELV after open and closed suction in patients with ARDS.

METHODS

This randomized crossover study included 20 patients receiving invasive mechanical ventilation for ARDS. Open and closed suction were applied in a random order. Lung impedance was measured using electric impedance tomography. The change in end-expiratory lung impedance end of suction and at 1, 10, 20, and 30 min after suction, was used to represent the change in EELV. Arterial blood gas analyses and ventilatory parameters such as the plateau pressure (Pplat), driving pressure (Pdrive), and compliance of the respiratory system (CRS) were also recorded.

RESULTS

Less volume loss was noted after closed suction than after open suction (mean ΔEELI: -2661 ± 1937 vs. -4415 ± 2363; mean difference: -1753; 95% CI [-2662, -844]; P = 0.001). EELI returned to baseline 10 min after closed suction but did not return to baseline even 30 min after open suction. After closed suction, the Pplat and Pdrive decreased while the CRS increased. Conversely, the Pplat and Pdrive increased while the CRS decreased after open suction.

CONCLUSIONS

Endotracheal aspiration may result in alveolar collapse due to loss of EELV. Given that closed suction is associated with less volume loss at end-expiration without worsening ventilatory parameters, it should be chosen over open suction in patients with ARDS.

Effects on Lung Gas Volume, Respiratory Mechanics and Gas Exchange of a Closed-Circuit Suctioning System during Volume- and Pressure-Controlled Ventilation in ARDS Patients

Mechanically ventilated patients periodically require endotracheal suctioning. There are conflicting data regarding the loss of lung gas volume caused by the application of a negative pressure by closed-circuit suctioning. The aim of this study was to evaluate the effects of suctioning performed by a closed-circuit system in ARDS patients during volume- or pressure-controlled ventilation. In this prospective crossover-design study, 18 ARDS patients were ventilated under volume and pressure control applied in random order. Gas exchange, respiratory mechanics and EIT-derived end-expiratory lung volume (EELV) before the suctioning manoeuvre and after 5, 15 and 30 min were recorded. The tidal volume and respiratory rate were similar in both ventilation modes; in volume control, the EELV decreased by 31 ± 23 mL, 5 min after the suctioning, but it remained similar after 15 and 30 min; the oxygenation, PaCO₂ and respiratory system elastance did not change. In the pressure control, 5 min after suctioning, EELV decreased by 35 (26–46) mL, the PaO₂/FiO₂ did not change, while PaCO₂ increased by 5 and 30 min after suctioning (45 (40–51) vs. 48 (43–52) and 47 (42–54) mmHg, respectively). Our results suggest minimal clinical advantages when a closed system is used in volume-controlled compared to pressure-controlled ventilation.

Intensive care nurses' knowledge and practice of evidence-based recommendations for endotracheal suctioning: a multisite cross-sectional study in Changsha, China

BACKGROUND

Endotracheal suctioning is one of the most frequently performed invasive procedures by intensive care nurses. Nurses should have adequate knowledge and skills to perform endotracheal suctioning based on the best evidence. Little is known about intensive care nurses' knowledge and practice of evidence-based endotracheal suctioning in Chinese hospitals. The purpose of this study was to investigate intensive care nurses' knowledge and practice of evidence-based recommendations regarding endotracheal suctioning. Specifically, the study aimed to examine (1) intensive care nurses' awareness of and adherence to endotracheal suctioning guidelines and (2) factors influencing their level of awareness and adherence.

METHODS

A cross-sectional survey of 310 staff nurses working in intensive care units was carried out at Changsha, China. Data on participants' characteristics, awareness of, and adherence to the endotracheal suctioning guidelines were collected through online questionnaires. Following univariate descriptive statistics, the Mann-Whitney U test and Kruskal-Wallis H test were performed using Software Package Statistical Analysis Version 23.0.

RESULTS

A total of 281 nurses completed and returned the survey (response rate = 90.6 %). One-half to three-quarters of the nurses knew 21 of the 26 evidence-based practices and believed their practices followed the guidelines. Over half of them were unaware of the difference between open and close suctions and the pros and cons of using hyperinflation. Almost 50 % of nurses believed some of their clinical practices did not follow the evidence-based recommendations, such as not routinely using normal saline and using 80-120 mmHg suction pressure during endotracheal suctioning. Nurses with endotracheal suctioning training demonstrated significantly higher awareness of endotracheal suctioning recommendations and higher adherence levels than untrained nurses.

CONCLUSIONS

The study findings revealed that Chinese intensive care nurses lacked awareness of several essential evidence-based endotracheal suctioning practices, and there were gaps between their current practice and the guideline recommendations. Further research should emphasize revealing barriers and facilitators of implementing evidence-based endotracheal suctioning practices as well as developing context-suitable interventions for guideline implementation.

Automated vs. conventional ventilation in the ICU: a randomized controlled crossover trial comparing blood oxygen saturation during daily nursing procedures (I-NURSING)

Background

Hypoxia is common during daily nursing procedures (DNPs) routinely performed on mechanically ventilated patients. The impact of automated ventilation on the incidence and severity of blood oxygen desaturation during DNPs remains unknown.

Methods

A prospective randomized controlled crossover trial was carried out in a French intensive care unit to compare blood oxygen pulse saturation (SpO₂) during DNPs performed on patients mechanically ventilated in automated and conventional ventilation modes (AV and CV, respectively). All patients with FiO₂ ≤ 60% and without prone positioning or neuromuscular blocking agents were included. Patients underwent two DNPs on the same day using AV (INTELLiVENT-ASV®) and CV (volume control, biphasic positive airway pressure, or pressure support ventilation) in a randomized order. The primary outcome was the percentage of time spent with SpO₂ in the acceptable range of 90–95% during the DNP.

Results

Of the 265 included patients, 93% had been admitted for a medical pathology, the majority for acute respiratory failure (52%). There was no difference between the two periods in terms of DNP duration, sedation requirements, or ventilation parameters, but patients had more spontaneous breaths and lower peak airway pressures during the AV period (p <  0.001). The percentage of time spent with SpO₂ in the acceptable range during DNPs was longer in the AV period than in the CV period (48 ± 37 vs. 43 ± 37, percentage of DNP period; p = 0.03). After adjustment, AV was associated with a higher number of DNPs carried out with SpO₂ in the acceptable range (odds ratio, 1.82; 95% CI, 1.28 to 2.6; p = 0.001) and a lower incidence of blood oxygen desaturation ≤ 85% (adjusted odds ratio, 0.50; 95% CI, 0.30 to 0.85; p = 0.01).

Conclusion

AV appears to reduce the incidence and severity of blood oxygen desaturation during daily nursing procedures (DNPs) in comparison to CV.

Trial registration

This study was registered in clinical-trial.gov (NCT03176329) in June 2017.

Graphical abstract

Evaluating the Effects of Post-Intubation Endotracheal Suctioning Before Surgery on Respiratory Parameters in Children with Airway Secretion

Background

Endotracheal suctioning (ETS) is a common procedure in intubated patients for the clearance of secretions and improvement of oxygenation.

Objectives

Owing to the controversies in previous studies, we studied the effects of open ETS before surgery on respiratory parameters in children with pulmonary crackles.

Methods

In this clinical trial, 100 children with pulmonary crackles, candidates for surgery were randomly assigned into two groups. After intubation, in the group A (n = 50), deep and open suction was done until the crackle was cleared and in the group B (n = 50), anesthesia without suctioning was continued. Hemodynamic and respiratory parameters were compared.

Results

The patients in group A had higher oxygen saturation with a statistically significant difference in 15th to 75th minutes of the operation (P < 0.001) and in post-anesthetic care unit (P = 0.004). After suction, before and after extubation, there was a statistically significant reduction of crackles in the group A in comparison to the group B (P < 0.001). There was no statistically significant difference in the end-tidal CO₂, airway pressure and respiratory rate between the two groups (P > 0.05). Relevant complications and the emergence of anesthesia time were statistically lower in the group A (P < 0.001). There was no statistically significant change in terms of blood pressure in the two groups (P > 0.05). The heart rate in the 15th, 30th, and 45th minutes of surgery was statistically lower in the group B (P < 0.05).

Conclusions

This study indicates positive effects of open and deep suction in improving oxygen saturation and reducing complications and emergence time. Pulmonary auscultation of the group A before and after weaning was statistically better than group B. However, this study found no positive effect of ETS on airway pressure, ETCO₂, blood pressure, and respiratory rate. Meanwhile, increased heart rate in the group A might introduce the potential risk of dysrhythmia and hemodynamic instability.

A comparison of the effects of manual hyperinflation and ventilator hyperinflation on restoring end-expiratory lung volume after endotracheal suctioning: A pilot physiologic study

PURPOSE

Endotracheal suctioning (ES) of mechanically ventilated patients decreases end-expiratory lung volume (EELV). Manual hyperinflation (MHI) and ventilator hyperinflation (VHI) may restore EELV post-ES but it remains unknown which method is most effective. The primary aim was to compare the efficacy of MHI and VHI in restoring EELV post-ES.

MATERIALS AND METHODS

ES was performed on mechanically ventilated intensive care patients, followed by MHI or VHI, in a randomised crossover design. The washout period between interventions was 1 h. End-expiratory lung impedance (EELI), measured by electrical impedance tomography, was recorded at baseline, during ES, during hyperinflation and 1, 5, 15 and 30 min post-hyperinflation.

RESULTS

Nine participants were studied. ES decreased EELI by 1672z (95% CI, 1204 to 2140) from baseline. From baseline, MHI increased EELI by 1154z (95% CI, 977 to 1330) while VHI increased EELI by 769z (95% CI, 457 to 1080). Five minutes post-VHI, EELI remained 528z (95% CI, 4 to 1053) above baseline. Fifteen minutes post-MHI, EELI remained 351z (95% CI, 111 to 592) above baseline. At subsequent time-points, EELI returned to baseline.

CONCLUSIONS

MHI and VHI effectively restore EELV above baseline post-ES and should be considered post suctioning.

"When no-one's looking," the application of lung recruitment and normal saline instillation with paediatric endotracheal suction: An exploratory study of nursing practice

BACKGROUND

The complex nature of the Paediatric Intensive Care Unit (PICU) patient requires the bedside nurse to make rapid, complex decisions regarding endotracheal suction (ETS) interventions. It is not understood what influences nurses' decision making in the context of ETS, however, the actions of the clinician have a direct impact on the efficacy of the ETS event and patient outcomes.

OBJECTIVES

To explore and describe the use of normal saline instillation and lung recruitment with paediatric ETS in a cohort of Australian nurses, and to identify factors that influence normal saline use with ETS.

METHODS

A descriptive, exploratory study. An evidence-based practice model formed the conceptual basis for the study. Semi-structured interviews were conducted with 12 nurses from an Australian tertiary referral paediatric intensive care unit. Audiotaped interviews were transcribed. Inductive thematic analysis was used to code and analyse the interview data and identify themes.

FINDINGS

Data analysis revealed three themes: patient's clinical presentation, clinician judgement and unit practice norms.

CONCLUSIONS

Variability in nurses ETS practice was marked. In the absence of evidence based clinical guidelines, nurses relied on knowledge derived from clinical experience and the local setting to guide NSI and LR intervention decisions. Participants reported uncertainty regarding ETS best practice and perceived the lack of research evidence as a barrier to making informed clinical decisions at the bedside. Rigorous research evaluating the safety and efficacy of NSI and LR with ETS is urgently required for patient care; however PICU nurses rely on multiple sources of evidence to inform ETS practice decision.

Physiological changes associated with routine nursing procedures in critically ill are common: an observational pilot study

BACKGROUND

Nursing procedures that are routinely performed in the intensive care unit (ICU) are assumed to have minimal side effects. However, these procedures may sometimes cause physiological changes that negatively affect the patient. We hypothesized that physiological changes associated with routine nursing procedures in the ICU are common.

METHODS

A clinical observational study of 16 critically ill patients in a nine-bed mixed university hospital ICU. All nursing procedures were observed, and physiological data were collected and subsequently analyzed. Minor physiological changes were defined as minimal changes in respiratory or circulatory variables, and major physiological changes were marked as hyper/hypotension, bradycardia/tachycardia, bradypnea/tachypnea, ventilatory distress, and peripheral blood oxygen desaturation.

RESULTS

In the 16 patients, 668 procedures generated 158 major and 692 minor physiological changes during 187 observational hours. The most common procedure was patient position change, which also generated the majority of the physiological changes. The most common major physiological changes were blood oxygen desaturation, ventilatory distress, and hypotension, and the most common minor changes were arterial pressure alteration, coughing, and increase in respiratory rate.

CONCLUSION

In this pilot study, we examined physiological changes in connection with all regular routine nursing procedures in the ICU. We found that physiological changes were common and sometimes severe.

Tracheal tube biofilm removal through a novel closed-suctioning system: an experimental study

BACKGROUND

Tracheal tube biofilm develops during mechanical ventilation. We compared a novel closed-suctioning system vs standard closed-suctioning system in the prevention of tracheal tube biofilm.

METHODS

Eighteen pigs, on mechanical ventilation for 76 h, with P. aeruginosa pneumonia were randomized to be tracheally suctioned via the KIMVENT* closed-suctioning system (control group) or a novel closed-suctioning system (treatment group), designed to remove tracheal tube biofilm through saline jets and an inflatable balloon. Upon autopsy, two tracheal tube hemi-sections were dissected for confocal and scanning electron microscopy. Biofilm area, maximal and minimal thickness were computed. Biofilm stage was assessed.

RESULTS

Sixteen animals were included in the final analysis. In the treatment and control group, the mean (sd) pulmonary burden was 3.34 (1.28) and 4.17 (1.09) log cfu gr(-1), respectively (P=0.18). Tracheal tube P. aeruginosa colonization was 5.6 (4.9-6.3) and 6.2 (5.6-6.9) cfu ml(-1) (median and interquartile range) in the treatment and control group, respectively (P=0.23). In the treatment group, median biofilm area was 3.65 (3.22-4.21) log10 μm2 compared with 4.49 (4.27-4.52) log10 μm2 in the control group (P=0.031). In the treatment and control groups, the maximal biofilm thickness was 48.3 (26.7-71.2) µm (median and interquartile range) and 88.8 (43.8-125.7) µm, respectively. The minimal thickness in the treatment and control group was 0.6 (0-4.0) µm and 23.7 (5.3-27.8) µm (P=0.040) (P=0.017). Earlier stages of biofilm development were found in the treatment group (P<0.001).

CONCLUSIONS

The novel CSS reduces biofilm accumulation within the tracheal tube. A clinical trial is required to confirm these findings and the impact on major outcomes.

The effect of the open and closed system suctions on cardiopulmonary parameters: time and costs in patients under mechanical ventilation

BACKGROUND

One of the measures to keep the airway open is suctioning of endotracheal tube in patients under ventilation. This procedure can be accompanied with some complications. Selection of appropriate method of suctioning can prevent incidence of acute complications.

OBJECTIVES

This study aimed to compare the effects of the open and closed system suctioning methods on blood pressure, mean arterial pressure, heart rate, percentage of arterial oxygen saturation, time, and costs in patients under mechanical ventilation.

PATIENTS AND METHODS

This clinical trial study was conducted on 40 patients in ICU. Patients' blood pressure, heart rate, arterial oxygen saturation, related costs, and length of suctioning procedure were measured and recorded immediately before and one, five, ten, and fifteen minutes after suctioning. Data were analyzed using paired t test and repeated measure analysis of variance.

RESULTS

No significant differences were observed between the two suctioning methods in terms of mean systolic blood pressure (P = 0.075), diastolic blood pressure (P = 0.405), and mean arterial pressure (P = 0.257) in the five consecutive measurements. However, significant changes were observed in heart rate (P = 0.025) and percentage of arterial oxygen saturation (P < 0.001). The mean lengths of time in open and closed suctioning methods were 5.59 ± 0.211 and 4.34 ± 0.039 seconds, respectively (P < 0.001). The cost of the closed system was lower than the open method for the patients who were admitted to ICU for longer than two days.

CONCLUSIONS

Closed suction caused fewer disturbances in patients' hemodynamic condition, took shorter time, and is more economical. Therefore, this method can replace open suction method in caring of severely critically ill patients.

[Effects of open or closed suctioning on lung dynamics and hypoxemia in mechanically ventilated patients]

PURPOSE

This study was conducted to compare effects of open and closed suctioning methods on lung dynamics (dynamic compliance, tidal volume, and airway resistance) and hypoxemia (oxygen saturation and heart rate) in mechanically ventilated patients.

METHODS

This study was a cross-over repeated design. Participants were 21 adult patients being treated with endotracheal intubation using a pressure-controlled ventilator below Fraction of Inspired Oxygen (FiO₂) 60% and PEEP 8 cmH₂O. Data were collected at baseline and 1, 2, 3, 4, 5, and 10 minutes after suctioning. Data were analyzed using two-factor ANOVA with repeated measures on time and suctioning type.

RESULTS

Effects of the interaction between suction type and time were significant for oxygen saturation and heart rate but not significant for dynamic compliance, tidal volume, or airway resistance. Prior to performance of suctioning, tidal volume and oxygen saturation were significantly lower, but airway pressure and heart rate were significantly higher using the closed suctioning method as compared with the open suctioning method.

CONCLUSION

For patients on ventilator therapy below FiO₂ 60% and PEEP 8cmH₂O, open suctioning performed after delivery of 100% FiO₂ using a mechanical ventilator may not have as much negative impact on lung dynamics and hypoxemia as closed suctioning.

Acute effects of physiotherapeutic respiratory maneuvers in critically ill patients with craniocerebral trauma

OBJECTIVE

To evaluate the effects of physiotherapeutic respiratory maneuvers on cerebral and cardiovascular hemodynamics and blood gas variables.

METHOD

A descriptive, longitudinal, prospective, nonrandomized clinical trial that included 20 critical patients with severe craniocerebral trauma who were receiving mechanical ventilation and who were admitted to the intensive care unit. Each patient was subjected to the physiotherapeutic maneuvers of vibrocompression and increased manual expiratory flow (5 minutes on each hemithorax), along with subsequent airway suctioning with prior instillation of saline solution, hyperinflation and hyperoxygenation. Variables related to cardiovascular and cerebral hemodynamics and blood gas variables were recorded after each vibrocompression, increased manual expiratory flow and airway suctioning maneuver and 10 minutes after the end of airway suctioning.

RESULTS

The hemodynamic and blood gas variables were maintained during vibrocompression and increased manual expiratory flow maneuvers; however, there were increases in mean arterial pressure, intracranial pressure, heart rate, pulmonary arterial pressure and pulmonary capillary pressure during airway suctioning. All of the values returned to baseline 10 minutes after the end of airway suctioning.

CONCLUSION

Respiratory physiotherapy can be safely performed on patients with severe craniocerebral trauma. Additional caution must be taken when performing airway suctioning because this technique alters cerebral and cardiovascular hemodynamics, even in sedated and paralyzed patients.

Efeitos da higienização brônquica nas variáveis cardiorrespiratórias de pacientes em ventilação mecânica

INTRODUÇÃO: Durante a ventilação mecânica (VM) as vias aéreas podem acumular secreção. Pacientes em VM são submetidos a Fisioterapia Respiratória (FR) e a aspiração traqueal, associados ou isoladamente, com objetivo de higienizar as vias aéreas. OBJETIVO: Comparar os efeitos da aplicação de diferentes protocolos de higiene brônquica na pressão arterial, frequência cardíaca, saturação de oxigênio e frequência respiratória de pacientes submetidos à VM. MATERIAIS E MÉTODOS: Realizou-se estudo prospectivo e aleatório, controlado do tipo cruzado, com amostra não probabilística intencional no Hospital das Clínicas da Faculdade de Medicina de Marília. Foram incluídos pacientes em VM invasiva que foram submetidos a três protocolos de higienização brônquica: PFR - protocolo de fisioterapia (compressão torácica manual e hiperinsuflação manual); PAT - protocolo de aspiração; e PFR + PAT. Frequência respiratória, pressão arterial sistólica (PAS), pressão arterial diastólica (PAD), saturação periférica de oxigênio e frequência cardíaca foram avaliadas em três momentos: antes (M1), imediatamente após (M2), e 30 minutos após (M3) cada protocolo. As diferenças entre protocolos e momentos foram verificadas por meio do teste ANOVA e pos-hoc de Student Newman-Keus (p < 0,05). RESULTADOS: Foram avaliados 18 pacientes com 71,2 ± 13,9 anos de idade e com 15,1 ± 17,7 dias de VM. Não houve diferenças entre os protocolos. Diminuíram de forma significativa a PAS (p = 0,0261) e a PAD (p = 0,0119) de M2 para M3 no protocolo de aspiração. CONCLUSÃO: Pacientes em VM apresentaram diminuição da pressão arterial após 30 minutos de aspiração e não apresentaram alteração nas outras variáveis estudadas. Não houve diferença entre os protocolos.

End-expiratory lung volume recovers more slowly after closed endotracheal suctioning than after open suctioning: a randomized crossover study

PURPOSE

Endotracheal suctioning causes significant lung derecruitment. Closed suction (CS) minimizes lung volume loss during suction, and therefore, volumes are presumed to recover more quickly postsuctioning. Conflicting evidence exists regarding this. We examined the effects of open suction (OS) and CS on lung volume loss during suctioning, and recovery of end-expiratory lung volume (EELV) up to 30 minutes postsuction.

MATERIAL AND METHODS

Randomized crossover study examining 20 patients postcardiac surgery. CS and OS were performed in random order, 30 minutes apart. Lung impedance was measured during suction, and end-expiratory lung impedance was measured at baseline and postsuctioning using electrical impedance tomography. Oximetry, partial pressure of oxygen in the alveoli/fraction of inspired oxygen ratio and compliance were collected.

RESULTS

Reductions in lung impedance during suctioning were less for CS than for OS (mean difference, -905 impedance units; 95% confidence interval [CI], -1234 to -587; P < .001). However, at all points postsuctioning, EELV recovered more slowly after CS than after OS. There were no statistically significant differences in the other respiratory parameters.

CONCLUSIONS

Closed suctioning minimized lung volume loss during suctioning but, counterintuitively, resulted in slower recovery of EELV postsuction compared with OS. Therefore, the use of CS cannot be assumed to be protective of lung volumes postsuctioning. Consideration should be given to restoring EELV after either suction method via a recruitment maneuver.

An evaluation of the implementation of a best practice guideline on tracheal suctioning in intensive care units

Aim  To minimise suctioning-induced complications in intensive care patients, it is crucial that nurses are able to perform the procedure safely and act in accord with research-based recommendations. This paper reports the process of developing, disseminating and implementing the best practice guideline and an evaluation of the process and outcomes of care during and following its implementation in intensive care units. Methods  The study was divided into four phases: (i) to develop the best practice guideline and plan strategies for its dissemination and implementation; (ii) to audit the current practice of nurses in the tracheal suctioning of patients in intensive care units with an artificial airway; (iii) to disseminate and implement the best practice guideline; and (iv) to evaluate the process as well as outcome of care following its implementation in intensive care units. Results  The pretest results indicate that gaps exist between actual nursing practice and recommendations based on research evidence. Most nurses performed the skills in accord with the best practice guideline, with 65% nurses scoring above the 70% level. The post-test audit results show that, overall, nurses demonstrated a good endotracheal suctioning technique, with 96% scoring above 75%, indicating an overall improvement in compliance with the guideline. A statistically significant difference was found between the pretest (73%) and post-test (89%) compliance scores (t = -7.67, P < 0.005). Conclusions  This implementation project highlights the importance of using a rigorous and systematic process to ensure the formal testing of an intervention. Some essential principles in implementing evidence are necessary, such as involving relevant staff and having a range of strategies and clear processes for implementation.

Diaphragm electromyographic activity as a predictor of weaning failure

PURPOSE

To compare breathing pattern descriptors and diaphragm electromyographic activity (EAdi)-derived indices obtained from a neurally adjusted ventilatory assist catheter during a spontaneous breathing trial (SBT) in patients successfully and unsuccessfully separated from the ventilator and to assess their performance as a potential marker to discriminate these two categories of patients.

METHODS

Fifty-seven ready-to-wean patients were included in a prospective observational study. During a 30-min SBT (pressure support 7 cmH(2)O, zero end expiratory pressure), tidal volume (V (T)) and respiratory rate (RR) were obtained from the flow signal at baseline and at 3, 10, 20 and 30 min during the SBT. EAdi-derived indices were simultaneously computed: maximum of the EAdi (EAdi(max)), area under the inspiratory curve of EAdi (EAdi(AUC)), the difference between EAdi(max) and EAdi(min) (∆EAdi), EAdi(max)/V (T), EAdi(AUC)/V (T) and ∆EAdi/V (T). Patients, successfully (success group; n = 35) and unsuccessfully (failure group; n = 22) separated from the ventilator were compared.

RESULTS

At baseline, the breathing pattern was similar in the two groups, whereas EAdi(max) and EAdi(AUC) were significantly lower in the success group (p < 0.05). In the failure group, RR and RR/V (T) increased significantly during the trial, V (T) decreased, whereas EAdi(max) and EAdi(AUC) did not change. At 3 min, the areas under the receiver operating characteristic-curve of RR/V (T) and the EAdi-derived indices to predict weaning outcome were 0.83 for the rapid shallow breathing index (RSBI), 0.84 for EAdi(max)/V (T) , 0.80 for EAdi(AUC)/V (T) (0.80) and 0.82 for ∆EAdi/V (T). The coefficient of variation for V (T) decreased in the failure group while that for EAdi(max) remained unchanged.

CONCLUSIONS

EAdi-derived indices provide reliable and early predictors of weaning outcome. However, the performance of these indices is not better than the RR/V (T).

Comparison of the effects of two humidifier systems on endotracheal tube resistance

PURPOSE

To compare the effects of two humidifier systems on endotracheal tube (ETT) resistance during mechanical ventilation, either an active heated humidifier (HH) or a passive heat and moisture exchanger (HME) was selected using current clinical recommendations.

METHODS

This was a prospective clinical cohort study performed in an intensive care unit. Gas conditioning was performed using the HH in 22 patients and the HME in another 22. Patients were matched for endotracheal tube diameter, days of mechanical ventilation, simplified acute physiology score II (SAPS II), and fluid balance.

RESULTS

Used-ETT resistance was measured immediately after extubation. Unused-ETT resistance was calculated with an identical, clean ETT. No differences were found between the HH and HME groups in ETT diameter (7.9 ± 0.4 vs. 7.9 ± 0.3 mm; p = 0.98), days of mechanical ventilation (11.3 ± 7.7 vs. 9.5 ± 4.5; p = 0.34), SAPS II (41.0 ± 13.6 vs. 42.0 ± 11.7; p = 0.79), or fluid balance (-2,552 ± 6,268 vs. -2,579 ± 5,422 mL; p = 0.98). ETT resistance increased from intubation to extubation: from 6.8 ± 1.1 to 10.6 ± 4.3 cmH(2)O L(-1) s(-1) in the HH group, (p < 0.001) and from 6.8 ± 1.1 to 10.2 ± 3.8 cmH(2)O L(-1) s(-1) in the HME group (p < 0.001), which is a 53% average increase in resistive load.

CONCLUSIONS

We did not find differences between the two types of humidifiers in terms of airflow resistance during prolonged mechanical ventilation when the devices were selected on the basis of individual clinical needs. The increase in resistive load is physiologically relevant.

Closed suctioning system: critical analysis for its use

AIM

To determine the efficacy and effectiveness of the closed suctioning system.

METHOD

Literature review articles were accessed from the following databases: PubMed, EMBASE, CINAHL, and Cochrane Library. The literature review criteria included: all publication styles except meta-analysis, participants that were > or =18 years, written in English, and published between 1973 and 2008.

RESULTS

This literature review revealed that the efficacy and effectiveness of the closed suctioning system remains to be demonstrated. The device manufacturers' studies focused on cost reduction, cross-contamination, and preservation of the oxygen saturation of patients during endotracheal suctioning; however, the clinical studies focused on the use of closed suctioning systems to prevent ventilator-associated pneumonia. The reviewed studies had small sample sizes with heterogeneous demographics and non-randomized controls. Recent studies suggest that closed suctioning systems are no better than open suctioning systems in terms of mortality, morbidity, or the cost-benefit ratio. A few studies did indicate that the closed suctioning system might reduce the loss of lung volume and oxygen desaturation.

CONCLUSION

The studies reviewed in this article suggest that the evidence on the efficacy and effectiveness of closed suctioning systems is inconclusive. Only limited populations will benefit clinically from the use of this device. There is a need for further studies with randomized controlled trials to explore the use of closed suction systems and to update current clinical practise guidelines.

The effect of suction method, catheter size, and suction pressure on lung volume changes during endotracheal suction in piglets

We aimed to identify the effect of suction pressure and catheter size on change in lung volume during open and closed endotracheal suction. Anesthetized piglets (n = 12) were intubated with a 4.0-mm endotracheal tube. Lung injury was induced with saline lavage. Three suction methods (open, closed in-line, and closed with a side-port adaptor) were performed in random order using 6, 7, and 8 French gauge (FG) catheters, at vacuum pressures of 80, 140, and 200 mm Hg. Lung volume change was measured with respiratory inductive plethysmography. Overall, open suction resulted in greater lung volume loss during and at 60-s postsuction than either closed method (p < 0.001). When open and closed methods were analyzed separately, volume change was independent of catheter size and suction pressure with open suction. With closed suction, volume loss increased with larger catheter sizes and higher suction pressures (p < 0.001). With an 8-FG catheter and suction pressure of 140 or 200 mm Hg, volume loss was equivalent with open and closed suction. Lung volume changes are influenced by catheter size and suction pressure, as well as suction method. With commonly used suction pressures and catheter sizes, closed suction has no advantage in preventing loss of volume in this animal model.

The effects of endotracheal suctioning on the accuracy of oxygen consumption and carbon dioxide production measurements and pulmonary mechanics calculated by a compact metabolic monitor

BACKGROUND

Open endotracheal suctioning (ETS), which is performed regularly in mechanically ventilated patients to remove obstructive secretions, can cause an immediate decrease in dynamic compliance and expired tidal volume and result in inadequate or inaccurate sidestream respiratory monitoring, necessitating prolonged periods of stabilization of connected metabolic monitors. We investigated the immediate effect of open ETS on the accuracy of oxygen consumption (VO2) and carbon dioxide production (VCO2) measurements and calculated lung mechanics, respiratory quotient, and resting energy expenditure in mechanically ventilated children without severe lung pathology, when using a compact modular metabolic monitor (E-COVX) continuously recording patient spirometry and gas exchange measurements.

METHODS

Open ETS was performed when clinically indicated in 11 children mechanically ventilated for sepsis or head injury. A total of 2800 pulmonary 1-min gas exchange measurements were recorded in 28 ETS instances for 50 consecutive minutes before and 50 min after the standardized procedure.

RESULTS

Pulmonary mechanics and indirect calorimetry did not differ between pre- and postsuction sets of measurements. Pre- and postsuction VO2, VCO2, dynamic airway resistance, dynamic compliance, and expiratory minute ventilation remained stable from 5 to 55 min after tracheal suctioning and did not differ among different ventilatory modes. Average paired differences of sequential pre- and postsuction VO2, VCO2, respiratory quotient, and resting energy expenditure were -0.6%, -1%, -0.1%, and -0.3%. Ratio differences between the first and the second periods of measurements (1-25 vs 26-50 sets of 1-min measurements) did not differ in the two groups.

CONCLUSIONS

Pulmonary mechanics and indirect calorimetry measurements are not influenced after uneventful open ETS in well-sedated patients. The E-COVX is able to reliably record spirometry and metabolic indices as early as 5 min after suctioning at different ventilator modes.

Gas exchange impairment induced by open suctioning in acute respiratory distress syndrome: impact of permissive hypercapnia

OBJECTIVE

To determine whether hypercarbia occurs following the use of open suctioning in lung lavage injured sheep and whether the baseline PaCO2 and duration of suctioning affect gas exchange.

DESIGN

Prospective laboratory evaluation.

SETTING

Animal laboratory in a university hospital.

SUBJECTS

Seven female Dorset sheep.

INTERVENTIONS

Lung lavage was used to create acute respiratory distress syndrome (ARDS). Mechanical ventilation was provided to produce different baseline PaCO2 levels.

MEASUREMENTS AND MAIN RESULTS

Lung injury was developed by isotonic saline lavage until the PaO2 decreased to 100-150 mm Hg on an FIO2 of 1.0, positive end-expiratory pressure (PEEP) 5 cm H2O, and tidal volume 10 mL/kg. Then tidal volume was decreased to 6 mL/kg. Open suctioning was performed on each animal. Each animal experienced four experimental conditions in random order (PaCO2 40 and 80 mm Hg and duration of suctioning 10 and 30 secs). Before each of the four experimental conditions, animals underwent lung recruitment continuous positive airway pressure 40 cm H2O for 40 secs to normalize volume history followed by ventilation for 15 mins where FIO2 and PEEP were set based on the ARDSNet FIO2/PEEP. Mean arterial blood pressure, heart rate, pulmonary artery pressure, pulmonary artery occlusion pressure, cardiac output, and arterial blood gases were measured before, 1 min after, and then every 2 mins after open suctioning for 30 mins. Neither the duration of suctioning nor the baseline level of CO2 had an important influence on the magnitude of the desaturation and the recovery of PO2 following suctioning (p < .05). Level of PEEP did influence the recovery of PaO2 following suctioning.

CONCLUSIONS

While neither baseline CO2 nor duration of suctioning affected the gas exchange alterations induced by endotracheal suction, high levels of PEEP can help to avoid the associated gas exchange abnormalities in ARDS.

Closed tracheal suction systems versus open tracheal suction systems for mechanically ventilated adult patients

BACKGROUND

Ventilator-associated pneumonia is a common complication in ventilated patients. Endotracheal suctioning is a procedure that may constitute a risk factor for ventilator-associated pneumonia. It can be performed with an open system or with a closed system. In view of suggested advantages being reported for the closed system, a systematic review comparing both techniques was warranted.

OBJECTIVES

To compare the closed tracheal suction system and the open tracheal suction system in adults receiving mechanical ventilation for more than 24 hours.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2006, Issue 1) MEDLINE, CINAHL, EMBASE and LILACS from their inception to July 2006. We handsearched the bibliographies of relevant identified studies, and contacted authors and manufacturers.

SELECTION CRITERIA

The review included randomized controlled trials comparing closed and open tracheal suction systems in adult patients who were ventilated for more than 24 hours.

DATA COLLECTION AND ANALYSIS

We included the relevant trials fitting the selection criteria. We assessed methodological quality using method of randomization, concealment of allocation, blinding of outcome assessment and completeness of follow up. Effect measures used for pooled analyses were relative risk (RR) for dichotomous data and weighted mean differences (WMD) for continuous data. We assessed heterogeneity prior to meta-analysis.

MAIN RESULTS

Of the 51 potentially eligible references, the review included 16 trials (1684 patients), many with methodological weaknesses. The two tracheal suction systems showed no differences in risk of ventilator-associated pneumonia (11 trials; RR 0.88; 95% CI 0.70 to 1.12), mortality (five trials; RR 1.02; 95% CI 0.84 to 1.23) or length of stay in intensive care units (two trials; WMD 0.44; 95% CI -0.92 to 1.80). The closed tracheal suction system produced higher bacterial colonization rates (five trials; RR 1.49; 95% CI 1.09 to 2.03).

AUTHORS' CONCLUSIONS

Results from 16 trials showed that suctioning with either closed or open tracheal suction systems did not have an effect on the risk of ventilator-associated pneumonia or mortality. More studies of high methodological quality are required, particularly to clarify the benefits and hazards of the closed tracheal suction system for different modes of ventilation and in different types of patients.

A comparison of the effectiveness of open and closed endotracheal suction

OBJECTIVE

To compare the effectiveness of open and closed endotracheal suction in recovering thin and thick secretions in normal and injured lungs during conventional and high frequency ventilation.

DESIGN AND SETTING

Randomised study in a paediatric intensive care model in the animal research laboratory of a tertiary paediatric hospital.

SUBJECTS

16 New Zealand White rabbits.

INTERVENTIONS

Anaesthetised animals were intubated with a 3.5-mm endotracheal tube. Simulated thin and thick secretions (iopamidol 2 ml, a watery radio-opaque fluid, and fluorescent mucin 1 ml) were instilled in turn 1 cm below the tube tip through a catheter placed via a tracheostomy. Open or closed suction, randomly assigned, was applied for 6s at -140 mmHg using a 6-F gauge catheter. Following lung injury with repeated saline lavage the procedure was repeated on conventional and high frequency ventilation.

MEASUREMENTS AND RESULTS

Iopamidol recovery was determined by digitally subtracting the post-contrast and post-suction radiographic images. Mucin recovery was determined by fluorescence assay of the aspirate. In the normal lung similar amounts were recovered by both suction methods. In the lavaged lung closed suction recovered less iopamidol during conventional (22 +/- 7.5%) and high frequency ventilation (11 +/- 2.4%) than open suction (36 +/- 2% and 22 +/- 8.1%, respectively). Mucin recovery was less with closed suction during conventional 32 +/- 28 microl) and high frequency ventilation (30 +/- 31 microl) than with open suction (382 +/- 235 microl and 24 +/- 153 microl).

CONCLUSIONS

In the injured lung closed suction was less effective than open suction at recovering thin and thick simulated secretions, irrespective of ventilation mode.

Open and closed endotracheal suction systems in mechanically ventilated intensive care patients: a meta-analysis

BACKGROUND

Closed suction systems (CSS) are increasingly replacing open suction systems (OSS) to perform endotracheal toilet in mechanically ventilated intensive care unit patients. Yet effectiveness regarding patient safety and costs of these systems has not been carefully analyzed.

OBJECTIVE

To review effectiveness of CSS and OSS, with respect to patient outcome, bacterial contamination, and costs in adult intensive care unit patients.

DATA SOURCE

Search of MEDLINE, CINAHL, EMBASE, and Cochrane databases and a manual review of article bibliographies.

STUDY SELECTION

Randomized controlled trials comparing CSS and OSS in adult intensive care unit patients were retrieved.

DATA EXTRACTION/SYNTHESIS

Assessment of abstracts and study quality was performed by two reviewers. Data were combined in meta-analyses by random effect models. Fifteen trials were identified. No significant differences were found in incidences of ventilator-associated pneumonia (eight studies, 1,272 patients) and mortality (four studies, 1,062 patients). No conclusions could be drawn with respect to arterial oxygen saturation (five studies, 109 patients), arterial oxygen tension (two studies, 19 patients), and secretion removal (two studies, 37 patients). Compared with OSS, endotracheal suctioning with CSS significantly reduced changes in heart rate (four studies, 85 patients; weighted mean difference, -6.33; 95% confidence interval, -10.80 to -1.87) and changes in mean arterial pressure (three studies, 59 patients; standardized mean difference, -0.43; 95% confidence interval, -0.87 to 0.00) but increased colonization (two studies, 126 patients; relative risk, 1.51; 95% confidence interval, 1.12-2.04). CSS seems to be more expensive than OSS.

CONCLUSIONS

Based on the results of this meta-analysis, there is no evidence to prefer CSS more than OSS.

Inflation lung mechanics deteriorates markedly after saline instillation and open endotracheal suctioning in mechanically ventilated healthy piglets

INTRODUCTION

Non-bronchoscopic bronchoalveolar lavage is an alternative to diagnostic bronchoscopy in pediatric patients, as fiberoptic bronchoscopes with aspiration channels are too large for small infants. There are many variations of the method in clinical practice, and saline instillation followed by open endotracheal suctioning is still commonly used. Lung function can deteriorate with these procedures, and we have investigated the effects on lung mechanics and oxygenation in healthy piglets.

METHODS

The lungs of anesthetized and mechanically ventilated piglets were recruited with CPAP 35 cmH2O. Thereafter we instilled 5 ml of saline into the endotracheal tube, followed by three breaths from the ventilator. Saline was retrieved through a suction catheter wedged far distally in the airway. The procedure was followed by a new recruitment maneuver. Complete inspiratory/expiratory pressure - volume loops (PV-loops) were obtained just before and 5 min after saline instillation. Arterial blood gases were collected at equivalent times in 14 similar piglets submitted to exactly the same procedure.

RESULTS

The inspiratory limb of the PV-loops changed markedly, as the lower inflection point was displaced towards higher pressures (P=0.004), and hysteresis measured at 15 and 30 cmH2O increased (P=0.004 and P=0.012, respectively). Although PaO2 decreased significantly (P=0.001), values after saline instillation/suctioning were still in the high normal range, that is, 22.2 +/- 2.6 kPa.

CONCLUSIONS

Opening pressures of the lungs increase markedly after saline instillation/suctioning in healthy piglets. In this situation, adequate recruitment maneuvers and PEEP might prevent lung collapse and deteriorations in arterial oxygenation.

Tracheal suction by closed system without daily change versus open system

BACKGROUND

Tracheal suctioning costs are higher with a closed tracheal suction system (CTSS) than with an open system (OTSS), due to the need for complete daily change as recommended by the manufacturer. However, is it necessary to change the closed system daily?

OBJECTIVE

To evaluate the tracheal suctioning costs and incidence of ventilator-associated pneumonia (VAP) using closed system without daily change vs OTSS.

DESIGN

Prospective and randomised study.

SETTING

An Intensive Care Unit in a university hospital.

PATIENTS

Patients requiring mechanical ventilation.

INTERVENTIONS

Patients were randomly assigned to CTSS without daily change or OTSS. We used a CTSS that allowed partial or complete change.

MEASUREMENTS AND RESULTS

There were no significant differences between both groups of patients (236 with CTSS and 221 with OTSS) in gender, age, diagnosis, APACHE-II score, mortality, number of aspirations per day, percentage of patients who developed VAP (13.9 vs 14.1%) or the number of ventilator-associated pneumonia per 1000 days of mechanical ventilation (14.1 vs 14.6). There were not significant differences in tracheal suctioning costs per patient/day between CTSS vs OTSS (2.3+/-3.7 vs 2.4+/-0.5 Euros; p=0.96); however, when length of mechanical ventilation was lower than 4 days, the cost was higher with CTSS than with OTSS (7.2+/-4.7 vs 1.9+/-0.6 Euros; p<0.001); and when length of mechanical ventilation was higher than 4days, the cost was lower with CTSS than with OTSS (1.6+/-2.8 vs 2.5+/-0.5 Euros; p<0.001).

CONCLUSION

CTSS without daily change is the optimal option for patients needing tracheal suction longer than 4 days.