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PubMed2005

An in vitro evaluation of the effectiveness of endotracheal suction catheters.

INTRODUCTION: Tracheal suction catheters (TSCs) are used to clear mucus from an endotracheal tube (ETT). The clearance rate is critical because airway mucus stasis leads to obstruction, but prolonged catheter suctioning can lead to hypoxemia. The rate of mucus clearance from an ETT is thought to be influenced by the properties of the mucus, the pressure used to suction the mucus, and the diameter of the catheter. In this study, different adult TSCs were evaluated for their ability to suction mucus simulants that had properties similar to airway mucus. METHODS: Six different 14F TSC designs were evaluated. All catheters had the same end hole size, but the two side holes were sized at 3 mm, 4 mm, or 5 mm. A coagulant (Polyox Water Soluble Resin Coagulant NF; Dow Chemical Company; Cary, NC) was mixed with water at concentrations of 0.5%, 1.5%, and 3.0% to simulate mucus or sputum. Suction effectiveness was evaluated by the mass percentage of the coagulant suctioned over 10 s at 100 mm Hg from an 8.0 ETT. MEASUREMENTS AND RESULTS: The 1.5% and 3.0% simulants had properties comparable to human airway mucus and sputum. Suction effectiveness was less with the 3.0% coagulant simulant compared with the 1.5% and 0.5% simulants. Suction effectiveness was greater (p < 0.01) with TSCs that had nonparallel holes and a side hole diameter of 5 mm when tested with the 1.5% and 3.0% simulants. However, no best catheter could be identified among TSCs when tested with the more liquid-like 0.5% simulant. CONCLUSIONS: Greater TSC side hole diameter and nonparallel positioning was important for suctioning mucus simulants that are similar to mucus or sputum. The distance between side holes, end hole size, suction force, and duration of suctioning were not tested but could also have an effect on TSC performance.

Catheterization↗

PubMed2000

Survey of nursing practices with closed-system suctioning.

BACKGROUND: The limited literature on closed-system suctioning suggests a need for further research in this area. Information is lacking about the frequency of use of the closed versus the open system of suctioning and about the current patterns of practice of closed-system suctioning among nurses. OBJECTIVES: To determine the frequency of use of closed- versus open-system suctioning by critical care nurses and to describe the endotracheal suctioning practices of nurses who use closed-system suctioning, in particular the current practice of hyperoxygenation and hyperinflation. METHODS: A survey developed by the investigators was mailed to a stratified proportional sample of 241 critical care nurses who are members of the American Association of Critical-Care Nurses in a tristate area in the mid-Atlantic region of the United States. The 19-item questionnaire included both open and forced-choice items. The response rate was 50%. RESULTS: Closed-system suctioning is common in the critical care setting, and current nursing practices of closed-system suctioning vary. Use of hyperoxygenation is more common than use of hyperinflation with closed-system suctioning. Nurses had knowledge deficits about the proper performance of hyperoxygenation and hyperinflation. CONCLUSIONS: Further research on closed-system suctioning is warranted, especially on the practices of hyperoxygenation and hyperinflation and the effect of these interventions on the prevention of suctioning-induced hypoxemia.

Adult↗

PubMed2001

Effects of phenobarbital on cerebral blood flow velocity after endotracheal suctioning in premature neonates.

OBJECTIVE: To examine the effect of phenobarbital administration on anterior cerebral artery blood flow velocity before and after endotracheal suctioning in premature neonates. DESIGN: Transcutaneous PO(2) (TcPO(2)), heart rate, mean arterial blood pressure (MABP), and Doppler velocimeter blood flow of the left anterior cerebral artery were measured before and immediately after 3 consecutive endotracheal suctioning procedures in premature neonates. Intravenous phenobarbital (20 mg/kg) was administered immediately after the first procedure. SETTING: Neonatal intensive care unit. PATIENTS: Nine neonates with a mean birth weight of 807 g (range, 620-1060 g) and a mean gestational age of 27 weeks (range, 25-30 weeks) were studied at age 8 to 12 hours. RESULTS: Transcutaneous PO(2) decreased in response to endotracheal suctioning at each of the suctioning procedures before and after phenobarbital was given (P<.001). Changes in heart rate were not observed. There were increases in MABP and area under the velocity curve (AUVC) per minute in response to endotracheal suctioning before but not after phenobarbital administration (P=.046). Use of phenobarbital lowered the overall peak systolic blood flow velocity in response to endotracheal suctioning (P =.02, analysis of variance, interactions for the effect of phenobarbital therapy on the response to suctioning). Changes in end-diastolic blood flow velocity were not observed. There were decreases in the differences before and after endotracheal suctioning for MABP at 2 and 4 hours and for AUVC and peak systolic blood flow velocity 4 hours after phenobarbital was given (P =.04). CONCLUSIONS: In very low-birth-weight neonates, endotracheal suctioning is associated with decreases in TcPO(2) and increases in MABP and AUVC. Treatment with phenobarbital attenuates the increases in MABP and AUVC but not the decreases in TcPO(2) after endotracheal suctioning.

Analysis of Variance↗

PubMed2004

Comparison of the effect of closed versus open endotracheal suction systems on the development of ventilator-associated pneumonia.

The aim of this study was to compare the effect of closed versus open endotracheal suction systems on the development of ventilator-associated pneumonia (VAP). A prospective, randomized, controlled trial was performed in a medical intensive care unit (MICU) of a university hospital in patients who received mechanical ventilation for more than 48 h. Patients were randomized to receive endotracheal suction with either closed catheters (closed suction group; N-41) or single-use catheters (open suction group; N=37). Cultures were taken from the ventilator tubing of 42 patients to determine the rate of colonization. There was no difference between the groups in terms of the frequency of development of VAP, mortality in the MICU, length of MICU stay and duration of mechanical ventilation. Thirteen patients in the open suction group and 16 patients in the closed suction group became colonized (P=0.14). The colonization rates by Acinetobacter spp. and Pseudomonas aeruginosa were more frequent in the closed suction group than in the open suction group (P<0.01 and P=0.04, respectively). In conclusion, closed endotracheal suction resulted in increased colonization rates of ventilator tubing with multi drug-resistant micro-organisms but did not increase the development of VAP and MICU outcome compared with open endotracheal suction.

Aged↗

PubMed1992

Does DeLee suction at the perineum prevent meconium aspiration syndrome?

OBJECTIVE: We attempted to determine the impact of "early" (before delivery of the chest) oronasopharyngeal DeLee suctioning at the perineum in the prevention of meconium aspiration syndrome and to confirm that meconium aspiration syndrome is a postnatal event. STUDY DESIGN: We compared infants with meconium-stained fluid who underwent "early" oronasopharyngeal DeLee suctioning with a similar group of infants whose airways were suctioned "late" (after chest delivery). Practicing obstetricians did not know the study was being conducted by the pediatric staff, and an independent observer documented whether obstetricians performed "early" or "late" oronasopharyngeal DeLee suctioning. Immediate postnatal tracheal suctioning was performed in both groups. The study was conducted in a private tertiary care center averaging 5800 deliveries annually. A consecutive sample of 438 infants with meconium-stained fluid was analyzed. Of these infants, 221 received "early" oronasopharyngeal DeLee suctioning, while 217 infants were suctioned "late". RESULTS: Of the 438 infants with meconium-stained fluid, meconium aspiration syndrome developed in 38 (9%). These infants had higher rates of fetal distress (i.e., abnormal fetal heart rates) and lower Apgar scores (< or = 6) than infants without meconium aspiration syndrome (58% vs 17% and 65% vs 13%, respectively; p < 0.001). Forty-five percent of the infants with meconium aspiration syndrome had renal failure during the first 20 hours of life. In spite of "early" oronasopharyngeal DeLee suctioning, 53% of the infants in this group had meconium below the vocal cords and meconium aspiration syndrome developed in 7%. The time of oronasopharyngeal DeLee suctioning did not affect the rate of meconium aspiration syndrome or the presence of meconium below the vocal cords. CONCLUSIONS: We concluded that "early" oronasopharyngeal DeLee suctioning at the perineum does not affect the rate of meconium aspiration syndrome. We speculate that meconium aspiration syndrome is predominantly an intrauterine event associated with fetal distress and that meconium in the airways is merely a "marker" of previous fetal hypoxia.

Chi-Square Distribution↗

PubMed2005

Effects of manual hyperinflation and suctioning in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia.

Ventilator-associated pneumonia results from bacterial colonisation of the aerodigestive tract or aspiration of contaminated secretions into the lower airways. As a consequence of infection of the lung parenchyma and alveolitis, accumulation of inflammatory exudates and infiltration of airway mucosa can lead to unfavourable respiratory mechanics in ventilator-associated pneumonia. Tracheal suction is often employed by nursing staff in the management of mechanically ventilated patients with ventilator-associated pneumonia but this technique has the potential to increase respiratory resistance. Manual hyperinflation is used by physiotherapists to improve lung volume and mobilise secretions and has been shown to increase lung compliance. The effect of manual hyperinflation on airway resistance has not been studied. This study aims to demonstrate an additional mechanical benefit to the respiratory system when manual hyperinflation and suction techniques are combined, by comparing the application of manual hyperinflation and suction with suction alone on static lung compliance (C(L)) and inspiratory resistance (R(AW)) in mechanically ventilated patients with ventilator-associated pneumonia. Fifteen adult patients with ventilator-associated pneumonia were recruited and acted as their own controls. Manual hyperinflation followed by suction (manual hyperinflation plus suction) and suction alone were applied consecutively, in random order, on two occasions, four hours apart. Respiratory variables, C(L) and R(AW), were measured five times and the averaged value documented. Data were recorded before, immediately after, and 30 minutes after each intervention protocol. C(L) increased by 22% and R(AW) decreased by 21%, up to 30 minutes after manual hyperinflation plus suction, but not after suction alone. This study suggests that manual hyperinflation in conjunction with suction induces beneficial changes in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia.

Adult↗

PubMed2006

Effect of endotracheal suction on lung dynamics in mechanically-ventilated paediatric patients.

Endotracheal suctioning is performed regularly in ventilated infants and children to remove obstructive secretions. The effect of suctioning on respiratory mechanics is not known. This study aimed to determine the immediate effect of endotracheal suctioning on dynamic lung compliance, tidal volume, and airway resistance in mechanically-ventilated paediatric patients by means of a prospective observational clinical study. Lung mechanics were recorded for five minutes before and five minutes after a standardised suctioning procedure in 78 patients intubated with endotracheal tubes < or = 4.0 mm internal diameter. Twenty-four patients with endotracheal tube leaks > or = 20% were excluded from analysis. There was a significant overall decrease in dynamic compliance (p < 0.001) and mechanical expired tidal volume (p = 0.03) following suctioning with no change in the percentage endotracheal tube leak (p = 0.41). The change in dynamic compliance was directly related to both endotracheal tube and catheter sizes. There was no significant change in expiratory or inspiratory airway resistance following suctioning (p > 0.05). Although the majority of patients (68.5%) experienced a drop in dynamic compliance following suctioning, dynamic compliance increased in 31.5% of patients after the procedure. This study demonstrates that endotracheal suctioning frequently causes an immediate drop in dynamic compliance and expired tidal volume in ventilated children with variable lung pathology, intubated with small endotracheal tubes, probably indicating loss of lung volume caused by the suctioning procedure. There is no evidence that suctioning reduces airway resistance.

Airway Resistance↗

PubMedDate not supplied

A national survey of endotracheal suctioning techniques in the pediatric population.

OBJECTIVE: To examine the current suctioning practices nationally of experienced pediatric intensive care unit (PICU) nurses. DESIGN: A written survey method was used for this descriptive study. POPULATION: All PICUs in the 92 hospitals listed in the 1991 National Association of Children's Hospitals and Related Institutions directory. PARTICIPANTS: Staff nurses with more than 3 years experience were requested to complete the questionnaire in relation to their endotracheal suctioning practices of PICU patients. RESULTS: The questionnaire was returned by 80 (90%) PICUs. A wide range of suctioning techniques were used. Most respondents reported hyperoxygenation, hyperventilation, and/or hyperinflation of the patient's respiratory system before suctioning. Nursing judgment and the patient's clinical condition were used to determine when a suctioning procedure was needed. Most respondents (71%) indicated inserting the suction catheter until resistance was met. Normal saline-solution irrigant was used by all but one respondent. A manual resuscitation bag was used routinely during suctioning. Eighty percent of respondents reported that few patients displayed an adverse response to the suctioning procedure. RECOMMENDATIONS: The study should be replicated with direct observations of actual PICU suctioning practices. Suctioning techniques should be examined in relation to specific groups of PICU patients. Further research is needed to determine the optimal practice for rates of hyperventilation, percentage of oxygen increase during hyperoxygenation, and pressure increase during hyperinflation.

Adult↗

PubMed2002

Suctioning: a review of current research recommendations.

Effective suctioning is an essential aspect of airway management in the critically ill. However, there are many associated risks and complications. These range from trauma and hypoxaemia to cardiac dysrhythmias and, in extreme cases, cardiac arrest and death. This paper identifies the current research recommendations for safer suctioning practices. The literature is reviewed in three parts: prior to suctioning; during suctioning; and post-suctioning. The recommendations prior to suctioning include patient assessment, patient preparation and hyperoxygenation. The recommendations during suctioning include appropriate catheter selection, depth of insertion, negative pressure, duration of procedure and number of suction passes. Measures for maintenance of asepsis, such as hand-washing, wearing gloves, goggles and aprons are other essential considerations, which must not be overlooked. The recommendations post-suctioning include reconnection of oxygen, patient assessment, reduction of oxygen to baseline level, and providing patient reassurance. In order to improve standards of care, it is imperative that nurses are aware of current research recommendations. This will enable nurses to make informed decisions about their own suctioning practices, based on the individual needs of the patient.

Clinical Nursing Research↗

PubMed1991

Physics and function of operating room suction.

A study was done to evaluate the performance of suction apparatus in the operating room. The investigation was prompted by perceived poor suction performance in a suite of new operating rooms built in accordance with Standards Australia (SA) specifications. SA performance tests were conducted on each of four suction outlets in nine operating rooms. All 36 outlets complied with SA standards for flow-rate (minimum 40 L/min) and occluded negative pressure (ONP; minimum -60 kPa). However, 24 collection units failed to comply with standards (ONP) of -40 kPa achieved in less than 4 s when a 4 L disposable suction apparatus was connected (mean time to ONP: 6.1 s, 95% confidence interval: 4.9, 7.3). When smaller capacity suction jars were substituted, more units met SA standards. The standards therefore need revision to include specification of the capacity of the collecting apparatus. Other factors that were found to degrade suction performance significantly were air leakage and defective shut-off valves. The physical principles involved in operating room suction are described. Surgeons and anaesthetists should understand these principles, and it is recommended that a simple pre-operative check of the suction apparatus should be carried out, as follows: (1) Turn the wall control knob fully on, and disconnect the suction apparatus. The gauge should register zero. (2) Connect the suction jars. If the indicated gauge pressure is in excess of -15 kPa, investigate the equipment for excessive resistance, particularly in the shut-off valve, which should be replaced with a new unit if necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Australia↗

PubMed1993

Hemodynamic changes during endotracheal suctioning are mediated by increased autonomic activity.

Endotracheal suctioning of intubated infants produces profound changes in cardiovascular and cerebral hemodynamics, but the mechanisms regulating these changes are not fully understood. To determine the role of the autonomic nervous system in regulating these physiologic changes, we investigated the effects of endotracheal suctioning on heart rate (HR), mean arterial blood pressure (MABP), and renal sympathetic nerve activity (RSNA) in nine ventilated newborn lambs. In the first part of the study (n = 6), ventilation was interrupted for suctioning. With suctioning (15 s), HR decreased by 39 +/- 6% (p < 0.05), whereas MABP and RSNA increased significantly (p < 0.05) by 36 +/- 5% and 68 +/- 8%, respectively. These changes were significantly (p < 0.05) larger than changes observed during disconnection from the ventilator (15 s) without suctioning. Administration of atropine (0.02 mg/kg) blocked the HR response to suctioning without altering MABP or RSNA changes. After bilateral vagotomy, suctioning produced no changes in any parameter. When a closed tracheal suction system was used and ventilation was maintained, suctioning again resulted in significant (p < 0.05) increases in MABP (+10 +/- 3%) and RSNA (+34 +/- 5%) and a decrease in HR (-15 +/- 4%). These data suggest that suctioning stimulates sympathoexcitatory receptors localized in large airways whose afferent fibers course within the vagus, resulting in increased sympathetic activity, which induces peripheral vasoconstriction and elevates MABP. In contrast, the HR response appears to be mediated by increased parasympathetic activity as this is abolished by atropine.

Animals↗

PubMed2005

Effects of open vs. closed system endotracheal suctioning on cerebral blood flow velocities in mechanically ventilated extremely low birth weight infants.

BACKGROUND: Endotracheal (ET) suctioning causes cardiovascular side effects and may impair cerebral hemodynamics. Subjectively, these effects are worse if patients are disconnected from the ventilator (open system suctioning, OSS) than if they remain connected to the ventilator during suctioning (closed system suctioning, CSS). It is uncertain whether the response to ET suctioning is similar in conventionally (CV) and high frequency (HF) ventilated patients. OBJECTIVES: To investigate if the mode of suctioning or of mechanical ventilation influences cerebral blood flow velocities (CBFVs) in extremely low birth weight (ELBW) infants. METHODS: Transcranial Doppler sonography in the middle cerebral artery during OSS and CSS in CV and HF ventilated ELBW infants. RESULTS: Forty-one measurements were performed in 19 infants within the first two weeks of life. Mean CBFVs decreased during suctioning from baseline 18.8 to 14.3 cm/s (-24%), increased thereafter to 24.7 cm/s (73%) and then returned to baseline (20.8 cm/s). Changes in CBFV were less pronounced in infants with higher baseline CBFVs. Heart rate decreased during ET suctioning and thereafter returned to baseline values. The alterations in CBFV and heart rate were both independent of the mode of ventilation or suctioning. CONCLUSIONS: The mode of suctioning or ventilation does not influence CBFVs in ELBW infants.

Blood Flow Velocity↗

PubMed2000

Bacterial contamination of suction tips used during surgical procedures performed on dogs and cats.

OBJECTIVE: To determine prevalence of bacterial contamination of surgical suction tips. SAMPLE POPULATION: Surgical tips used during 44 surgical procedures performed on 42 dogs and 2 cats. PROCEDURE: Surgical procedures were classified into 1 of 3 categories according to degree of bacterial contamination of the surgical site (clean, clean-contaminated, contaminated). Two sets of suction apparatuses were used for test and control suction tips. Test tips were used normally to suction blood and fluid, whereas control tips were placed on the surgical drapes but not in the surgical wound. Suction tips were collected aseptically and placed into thioglycolate broth tubes for qualitative aerobic and anaerobic bacterial culture at the end of each procedure. RESULTS: Test and control suction tips were contaminated with bacteria during 30 of 44 (68%) procedures. Staphylococcus spp were the predominant bacteria in tips used during clean and clean-contaminated surgeries. When surgery was performed on clean-contaminated or contaminated wounds, prevalence of isolation of other bacteria such as Pseudomonas spp, Streptococcus spp, and Escherichia coli from both test and control suction tips was higher than for clean wounds. Mean time of procedures during which both test and control suction tips became contaminated was not significantly different from time of procedures during which neither tip became contaminated. CONCLUSION AND CLINICAL RELEVANCE: Surgical suction tips often become contaminated during standard veterinary surgical procedures. The risk of wound infection after surgery may be influenced by bacterial contamination of surgical suction tips.

Animals↗

PubMedDate not supplied

The effect of different endotracheal suction procedures on arterial blood gases in a controlled experimental model.

In an anesthetized hypoxemic animal model, 15 seconds of endotracheal suctioning, using a suction pressure of --170 mm. Hg and endotracheal tube to suction catheter ratio of 1.87 to 1, produced a 13 mm. Hg fall in arterial oxygen tension. Oxygen tension did not return to control level even at 5 minutes after suctioning. Giving 100 per cent oxygen before suctioning prevented suction-induced hypoxemia during and immediately after suctioning, but at 5 minutes after suctioning, oxygen tension fell below control levels. Mechanical lung hyperinflation with room air after suctioning quickly raised arterial oxygen tension above control levels. When mechanical ventilation using 100 per cent oxygen was maintained before, during, and after the suction procedure, arterial oxygen tension remained elevated at all times.

Animals↗

PubMed1995

Endotracheal suctioning: time-worn ritual or timely intervention?

BACKGROUND: Although many investigators have assessed the technique of endotracheal tube suctioning, the tissue of how frequently it should be performed remains controversial. No objective data is available to determine the answer. OBJECTIVE: To determine the criteria nurses use to make decisions regarding endotracheal suctioning. METHOD: Twenty-four registered nurses of varying levels of experience were asked a series of open-ended questions related to their theoretical knowledge, their ability to apply this knowledge, their suctioning practice, and how they made decisions regarding suctioning. RESULTS: All participants believed their patients required suctioning every 1 to 3 hours, with 17 performing it every 2 to 3 hours. Twenty criteria of which nine related to frequency were used in determining suctioning requirements. Eleven related to recognizing the need for immediate suctioning and were concerned with changes in the patient's condition. Common significant changes included desaturation, hemodynamic changes, loss of color, and blood gas changes. No single criterion was identified by all nurses. No differences were apparent between experienced and less experienced nurses. CONCLUSIONS: The large number of criteria identified suggests that the decision to suction is a complex one. It is a concern that many nurses rely on a deterioration in the patient's condition to indicate when suctioning is required. A policy of suctioning as necessary is provision of clear guidelines and education of all staff.

Adolescent↗

PubMed1995

Physiologic response to two endotracheal suctioning techniques in newborn lambs with and without acute pulmonary hypertension.

BACKGROUND: Endotracheal suctioning may cause sudden increases in pulmonary arterial pressure, which can result in hypoxia secondary to right ventricular failure and/or increased right-to-left shunting. An adaptor that allows suctioning without disconnecting the ventilator has been proposed to prevent these problems; however, its efficacy has not been rigorously studied. OBJECTIVE: To examine the physiologic responses to two endotracheal suctioning techniques in newborn lambs with and without acute pulmonary hypertension. METHODS: A repeated-measures design was used to compare two endotracheal suctioning techniques in seven newborn lambs with and without acute pulmonary hypertension. An adaptor was used in the ventilator-controlled technique, making disconnection of the ventilator during suctioning unnecessary. In the bag-controlled technique, the ventilator was disconnected and ventilation was done with a manual resuscitation bag. Physiologic variables, pulmonary and mean arterial pressure, peak inspiratory pressure, mixed venous oxygen saturation, cardiac index, and arterial blood gas values were recorded before, during, and after endotracheal suctioning. RESULTS: Endotracheal suctioning caused a statistically significant systemic hypertensive response in lambs with and without acute pulmonary hypertension, regardless of which suctioning technique was used. No statistically significant changes occurred in pulmonary arterial pressure using either technique. CONCLUSIONS: Use of an adaptor resulted in no differences in the physiologic responses to endotracheal suctioning. However, endotracheal suctioning was easier to perform using an adaptor because no extra equipment or person was needed.

Animals↗

PubMedDate not supplied

Linking cranial kinematics, buccal pressure, and suction feeding performance in largemouth bass.

The rate and magnitude of buccal expansion are thought to determine the pattern of water flow and the change in buccal pressure during suction feeding. Feeding events that generate higher flow rates should induce stronger suction pressure and allow predators to draw prey from further away. We tested these expectations by measuring the effects of prey capture kinematics on suction pressure and the effects of the latter on the distance from which prey were drawn-termed suction distance. We simultaneously, but not synchronously, recorded 500-Hz video and buccal pressure from 199 sequences of four largemouth bass, Micropterus salmoides, feeding on goldfish. From the video, we quantified several kinematic variables associated with the head and jaws of the feeding bass that were hypothesized to affect pressure. In a multiple regression, kinematic data accounted for 79.7% of the variation among strikes in minimum pressure. Faster mouth opening and hyoid depression were correlated with lower pressures, a larger area under the pressure curve, and a faster rate of pressure reduction. In contrast, buccal pressure variables explained only 16.5% of the variation in suction distance, and no single pressure variable had a significant relationship with suction distance. Thus, although expected relationships between head kinematics and buccal pressure were confirmed, suction distance was only weakly related to buccal pressure. Three explanations are considered. First, bass may not attempt to maximize the distance from which prey are drawn. Second, the response of prey items to suction-induced flow depends on prey behavior and orientation and is, therefore, subject to considerable variation. Third, previous theoretical work indicates that water velocity decays exponentially with distance from the predator's mouth, indicating that variation among strikes in flow at the mouth opening is compressed away from the mouth. These findings are consistent with other recent data and suggest that suction distance is a poor metric of suction feeding performance.

Animals↗

PubMed2001

The effect of closed system suction on airway pressures when using the Servo 300 ventilator.

OBJECTIVES: To measure airway pressures during closed system suctioning with the ventilator set to three differing modes of ventilation. METHODS: Closed system suctioning was conducted in 16 patients following cardiac surgery. Suctioning was performed using a 14 French catheter with a vacuum level of -500 cmH2O through an 8.0 mm internal diameter endotracheal tube. The lungs were mechanically ventilated with a Servo 300 ventilator set to one of three ventilation modes: volume-control, pressure-control or CPAP/pressure support. Airway pressures were measured via a 4 French electronic pressure transducer in both proximal and distal airways. RESULTS: Following insertion of the suction catheter, end-expiratory pressure increased significantly (p < 0.001) in both pressure-control and volume-control ventilation. This increase was greatest (p = 0.018) in volume-control mode (2.7 +/- 1.7 cmH2O). On performing a five second suction, airway pressure decreased in all modes, however the lowest airway pressure in volume-control mode (-4.9 +/- 4.0 cmH2O) was significantly (p = 0.001) less than the lowest airway pressure recorded in either pressure-control (0.8 +/- 1.9 cmH2O) or CPAP/pressure support (0.4 +/- 2.8 cmH2O) modes. In CPAP/pressure support mode, 13 of the 16 patients experienced a positive pressure 'breath' at the end of suctioning with airway pressures rising to 21 +/- 1.6 cmH2O. CONCLUSIONS: Closed system suctioning in volume control ventilation may result in elevations of end-expiratory pressure following catheter insertion and subatmospheric airway pressures during suctioning. Pressure control ventilation produces less elevation of end-expiratory pressure following catheter insertion and is less likely to be associated with subatmospheric airway pressures during suctioning. CPAP/pressure support has no effect on end-expiratory pressure following catheter insertion and subatmospheric airway pressures are largely avoided during suctioning.

Journal Article↗