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Effects of endotracheal tube suctioning on arterial oxygen tension and heart rate variability.

The purpose of this study was to examine the autonomic mechanisms underlying changes in heart rate (HR) and systolic blood pressure (SBP) responses to endotracheal tube (ETT) suctioning and to compare the open versus closed methods of ETT suctioning on these measures and on arterial oxygen tension. Eighteen orally intubated participants, 33 to 82 years of age (M = 60 years), were randomized for the order of suctioning method. Arterial oxygen tension (PaO2) was measured before suctioning and 30 s and 5 min following suctioning. Beat-to-beat HR and arterial blood pressure data were collected for 10-min periods before and after suctioning. HR and SBP measures were analyzed before suctioning and 1 min and 5 min following suctioning. Although there were no significant effects of ETT suctioning on the autonomic mechanisms of HR modulation and no significant differences between the two methods of suctioning, ETT suctioning resulted in an increase in HR, SBP, and PaO2. However, there was a decrease in the parasympathetic nervous system indicator of HR variability (HRV) following open suctioning. All patients in this study maintained a PaO2 level 80 mm Hg, which may account for our lack of significant autonomic changes. This suggests that hyperoxygenation with 100% oxygen for a minimum of 1 min (or 20 breaths), as delivered by preoxygenation modes available on most microprocessor ventilators, should be the method of choice for all hyperoxygenation procedures to avoid a decrease in PaO2 following suctioning.

Adult↗

Effects of a closed tracheal suction system on ventilatory and cardiovascular parameters.

OBJECTIVE: To determine whether patients ventilated in the assist-control mode experienced a change in oxygenation, respiratory rate, inspiratory:expiratory ratio, heart rate, blood pressure or acid-base balance when suctioned with a closed tracheal suction system. DESIGN: A quasi-experimental, within-subject, repeated-measures design was used. SUBJECTS: 18 patients ventilated on a fraction of inspired oxygen of 0.47 +/- 0.17 and 2.3 +/- 5.0 cm H2O positive end-expiratory pressure. INTERVENTIONS: Two suction passes were performed, with measurements at baseline, immediately after the first suction pass, immediately before the second suction pass, immediately after the second suction pass, 2 minutes after the second suction pass and 5 minutes after the second suction pass. No hyperoxygenation was used. RESULTS: Significant differences were seen over time for arterial oxygen saturation, respiratory rate and inspiratory:expiratory ratio. Arterial oxygen saturation decreased to less than 90% in four subjects (range 88% to 89%), with a maximum fall of 9%. No significant differences were seen for heart rate, blood pressure, partial pressure of carbon dioxide, bicarbonate, time to nadir (lowest arterial oxygen saturation) or recovery time. CONCLUSIONS: Subjects ventilated in the assist-control mode and suctioned with a closed tracheal suction system did not experience significant changes in cardiovascular or acid-base parameters when suctioned without hyperoxygenation. Although most subjects did not become desaturated, four subjects experienced desaturation at one or more intervals. To prevent desaturation, hyperoxygenation should be used before and after suctioning with a closed tracheal suction system.

Aged↗

Portable airway-suction systems: a comparison of performance.

UNLABELLED: A number of portable suction systems (powered either manually, pneumatically, or electrically) are available. We compared the performance of three electric systems (Laerdal Medical LSU, Laerdal Medical CSU, and Matrx Medical) and two manual systems (Vitalograph Emergency Aspirator and California Medical V-VAC) to wall suction set at maximum pressure of 300 torr [39.9 kPa]. METHODS: We determined the maximum pressure each system was capable of generating, and we measured the volume of imitation maple syrup each system at maximum pressure could suction within 5 seconds and the time required by each system at maximum pressure to suction 150 mL of syrup. In addition, we evaluated the life of each electric system's internal battery. RESULTS: All the electric systems were capable of generating suction pressure greater than 300 torr [39.9 kPa]. The amount of time required by the electric systems to suction 150 mL of syrup was not significantly different from that required by wall suction. In 5 seconds, wall suction suctioned a significantly greater volume of syrup than did the Matrx Medical system (p less than 0.05, ANOVA), but a significantly smaller volume of syrup than did the Laerdal Medical CSU system (p less than 0.05, ANOVA). The manual Vitalograph Emergency Aspirator was capable of generating 300 torr [39.9 kPa] pressure, but the California Medical V-VAC was not. Wall suction significantly outperformed both of the manual systems when volume of syrup suctioned in 5 seconds and time required to suction 150 mL of syrup were compared (P less than 0.05 ANOVA). All electric systems were capable of maintaining maximum suction greater than 15 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

Deep versus shallow suction of endotracheal tubes in ventilated neonates and young infants.

BACKGROUND: Mechanical ventilation is commonly used in Neonatal Intensive Care Units to assist breathing in a variety of conditions. Mechanical ventilation is achieved through the placement of an endotracheal tube (ETT) which is left in-situ. The ETT is suctioned to prevent a build-up of secretions and therefore blockage of the airway. Methods of suctioning the endotracheal tube vary according to institutional practice and the individual clinician performing the task. The depth of suctioning is one of these variables. The catheter may be passed to the tip of the ETT or beyond the tip into the trachea or bronchi to facilitate removal of secretions. However, trauma to the lower airways may result from the suction catheter being passed into the airway beyond the tip of the endotracheal tube. OBJECTIVES: To compare the effectiveness and complications of deep (catheter passed beyond the tip of the ETT) versus shallow (catheter passed to length of ETT only) suctioning of the endotracheal tube in ventilated infants. SEARCH STRATEGY: Using text words and subject headings relevant to endotracheal suctioning, searches were made of the Oxford Database of Perinatal Trials, Cochrane Register of Controlled Trials (The Cochrane Library, Issue 3, 2002), MEDLINE (from January 1966 to December 2002, all languages), CINAHL (from 1982 to 2002). In addition, a call was placed on the list servers, NICU-NET and Neonatal-Talk for unpublished trials, conference presentations and current trials. SELECTION CRITERIA: Controlled trials using random or quasi-random allocation of neonates receiving ventilatory support via an endotracheal tube to either deep or shallow endotracheal suctioning. DATA COLLECTION AND ANALYSIS: No studies were found meeting the criteria for inclusion in this review MAIN RESULTS: No studies were found meeting the criteria for inclusion in this review REVIEWER'S CONCLUSIONS: There is no evidence from randomised controlled trials concerning the benefits or risks of deep versus shallow suctioning of endo-tracheal tubes in ventilated neonates and infants. Further high quality research would be required to conclusively establish whether there are any benefits to deep or shallow suctioning. However, as it may be considered unethical to conduct a trial of deep suctioning given anecdotal evidence regarding possible damage to the airway, it is proposed that a randomised controlled trial comparing deep with shallow suctioning may be considered in a NICU where the standard practice includes a deep suctioning technique.

Humans↗

A new device with pressure regulation for microsurgical suction: technical note.

A new suction tube that allows precise control of suction pressure during microsurgical procedures is described. The new device consists of a suction tube that has a series of small holes on its proximal end. These holes can be progressively opened or closed by a laterally placed sliding bar. The surgeon can readily adjust the suction pressure by slightly moving his thumb up and down with accordance to his convenience during the operation. This creates an easy and prompt way to regulate suction pressure, thus removing the need of suction adjustment by the assistant or the scrub nurse. This new device provides an easy, precise, and quick suction regulation during the different stages of the microsurgical procedure. When the holes are totally closed, a maximum suction pressure is achieved, and when the holes are fully opened the suction pressure can be brought to zero. This device is very simple and ergonomic and allows an adjustable suction pressure mechanism that is regulated by the surgeon. By smoothly using the thumb to move the sliding bar up and down, the suction pressure may vary within the range of a maximum to zero almost instantaneously providing the appropriate suction pressure at any surgical time.

Brain↗

Can nurses safely assess the need for endotracheal suction in short-term ventilated patients, instead of using routine techniques?

Most literature describes endotracheal suction as a hazardous procedure associated with numerous complications and proposes that it should only be performed as necessary to minimize these complications. Other authors suggest endotracheal suction only after assessment predisposes patients to a number of different complications. This article describes a controlled study to compare and contrast the differences in endotracheal suction outcomes in patients who received ritualized 2 hourly suctioning and those who received it following assessment. A group of qualified nurses in an Intensive Care Unit were taught auscultation skills to assess a patient's needs for suctioning and all the nurses received educational training regarding endotracheal suctioning. Short-term ventilated patients were allocated to receive endotracheal suctioning either when the need for it was determined by assessment only or routinely, using a standardized suctioning technique. The results demonstrated a clear increase in nurses' knowledge regarding endotracheal suctioning. The assessed group of patients demonstrated significantly better outcomes and less complications than the controlled group in relation to changes in peak airway pressures, heart rate and mean arterial pressure pre- and post-endotracheal suctioning, and the amount of secretions obtained on suctioning. Although only preliminary, these results do provide support for the view that endotracheal suction only in response to assessment is better practice for short-term ventilated patients.

Auscultation↗

Infant nasal-pharyngeal suctioning: is it beneficial?

PURPOSE: To identify and validate the indicators registered nurses (RNs) use when deciding whether or not infants experiencing respiratory illnesses require nasal pharyngeal (NP) suctioning. METHOD: The first part of this study involved 43 RNs completing a questionnaire that examined the assessment parameters RNs use in determining when to perform NP suctioning. The second part of this study involved assessing infants' respiratory status before and after NP suctioning to determine what, if anything, changed post suctioning. FINDINGS: The three assessment parameters most frequently used by nurses in determining the need for suctioning were pulse oximeter readings, visible secretions, and audible secretions. The only three parameters to show statistically significant improvement post suctioning were pulse oximeter readings, visible secretions, and audible secretions. CONCLUSIONS: Nurses are using valid assessment parameters when determining the need for infant NP suctioning, and NP suctioning does improve certain aspects of infants' respiratory status. There are presumed benefits to NP suctioning. However, there are also potential risks. Nasal-pharyngeal suctioning can produce bradycardia, laryngospasm, cardiac dysrhythmias, and edema and trauma to mucous membranes (Oberc, 1991), tachycardia, emotional distress, bronchospasm, and cardiac arrest (Young, 1988). The procedure involves inserting a catheter into an infant's nose and advancing it to the back of the throat (pharynx) approximately 4-8 cm (Oberc, 1991). Once at the pharynx, suction is intermittently applied and the catheter is slowly removed. The purpose of NP suctioning is to clear the airway of an infant who is unable to do so independently. However, the effectiveness and outcomes of this procedure have not been supported by research.

Female↗

The impact of closed endotracheal suctioning systems on mechanical ventilator performance.

BACKGROUND: Closed endotracheal suctioning during mechanical ventilation is increasingly used, but its impact on ventilator function has not been fully studied. METHODS: We evaluated the impact of closed suctioning with 11 critical-care ventilators, during assisted ventilation in pressure-support mode, pressure-assist/control mode, volume-assist/control mode, and during continuous positive airway pressure, with 2 suctioning pressures (-120 mm Hg and approximately -200 mm Hg), and with 2 tidal volumes (450 mL and 900 mL). We continuously measured airway pressure, flow at the airway, and pressure distal to the catheter tip, before, during, and after a single 15-second period of continuous suctioning. RESULTS: No ventilator malfunctioned as a result of the closed suctioning. During suctioning, end-expiratory pressure markedly decreased in all modes, and peak flow increased in all modes except volume-assist/control (p < 0.001). Respiratory rate increased during suctioning in pressure- and volume-assist/control (p < 0.001) but not during pressure support or continuous positive airway pressure. Gas delivery was most altered during volume-assist/control with the smaller tidal volume (p < 0.05) and least altered during pressure-assist/control with the larger tidal volume. CONCLUSION: There are large differences between the ventilators evaluated (p < 0.001). Closed suctioning does not cause mechanical ventilator malfunction. Upon removal of the suction catheter, these ventilators resumed their pre-suctioning-procedure gas delivery within 2 breaths, and, during all the tested modes, all the ventilators maintained gas delivery. However, closed suctioning can decrease end-expiratory pressure during suctioning.

Equipment Design↗

The impact of endotracheal suctioning on gas exchange and hemodynamics during lung-protective ventilation in acute respiratory distress syndrome.

OBJECTIVE: To evaluate the respiratory and hemodynamic effects of open suctioning (OS) versus closed suctioning (CS) during pressure-control (PC) and volume-control (VC) ventilation, using a lung-protective ventilation strategy in an animal model of acute respiratory distress syndrome (ARDS). SETTING: Animal laboratory in a university hospital. DESIGN: Randomized cross-over evaluation. ANIMALS: Eight female Dorset sheep. INTERVENTIONS: Lung lavage was used to simulate ARDS. We applied VC and PC mechanical ventilation with a tidal volume of 6 mL/kg and positive end-expiratory pressure (PEEP), adjusted based on a table of PEEP versus fraction of inspired oxygen (FIO2). Suctioning was performed for 10 s with a suction pressure of -100 mm Hg, during both OS and CS. OS and CS were randomly performed with each animal. Hemodynamics and arterial blood gases were recorded before, during, and after endotracheal suctioning. RESULTS: The PaO2/FIO2 ratios before suctioning were similar in all groups, as were the PEEP and FIO2. PaO2/FIO2 was lower after OS than after CS/VC or CS/PC. There was no post-suctioning difference in oxygenation between CS/VC and CS/PC. PaCO2 recorded 10 min after suctioning was greater than the presuctioning value, in all groups. Intrapulmonary shunt fraction increased between baseline and 10 min post-suctioning with OS and CS/VC, but did not significantly increase with CS/PC. There were no significant changes in hemodynamics pre-suctioning versus post-suctioning with OS, CS/VC, or CS/PC. CONCLUSION: PaO2/FIO2) was better maintained during CS with both VC and PC modes during lung-protective ventilation for ARDS, as compared with OS, and shunt fraction post-suctioning changed least with PC.

Animals↗

Differential effects of continuous versus intermittent suction on tracheal tissue.

The purpose of this study was to determine the differential effect of continuous versus intermittent application of negative pressure on tracheal tissue during endotracheal suctioning. The sample consisted of 12 mongrel dogs, randomly assigned to group 1 (N = 5), continuous suction, or group 2 (N = 5), intermittent suction. All animals were orally intubated (40F endotracheal tube). Two control animals were intubated and not suctioned. Animals in group 1 and 2 were suctioned every 15 minutes for 4 hours for a total of 16 suction passes. Endotracheal suctioning was performed by using a 14F suction catheter either continuously (10 seconds) or intermittently (2 seconds with, 1 second without for a total of 10 seconds) at a suction pressure of 200 mm Hg and a suction flow rate of 16 L/min. Tracheal tissue samples were examined for simplified and major simplified damage, ulceration, and ulceration with necrosis. Results indicated that all forms of damage were present with both suctioning techniques. No significant differences were found between group 1 and group 2 (Wilcoxon rank sum) for any of the alterations. Results indicate that both continuous and intermittent application of negative pressure with endotracheal suction produces significant damage to tracheal tissue.

Animals↗

Endotracheal suctioning-induced heart rate alterations.

The purpose of the experimental study was to identify mechanical and/or neural factors contributing to the heart rate alterations associated with endotracheal suctioning (ETS). Effects of catheter insertion alone and catheter insertion with the application of negative pressure on the partial pressure of arterial oxygen (PaO2) and heart rate prior to and following vagal blockade with atropine were examined. Eleven newborn swine less than 24 h of age were randomly exposed to (a) suction catheter insertion alone and (b) suction catheter insertion and the application of suction. Preoperatively, the subjects were anesthetized with ketamine and xylazine (.05 mL/kg). The ECG in lead II was recorded on a Gould 2600S recorder. Arterial blood (aB) O2 levels were withdrawn 1 min before and at 20 s, 1 min, 2 min, and 3 min following ETS and analyzed on a calibrated Corning 158 semi-automated aB gas machine. There was a significant decline in PaO2 from baseline at 20 s post ETS in both the no suction and suction protocols, p less than .05. The application of suction caused a greater decline in mean PaO2 (41 torr) compared to no suction (13 torr) at 20 s post ETS which was similar in pattern following vagal blockade (suction: 37 torr; no suction: 2 torr). Following the first pass of the catheter, mean heart rate (HR) declined 14 beats per min with suction and 9 beats per min with no suction. The difference was obliterated following the second pass of the catheter. There was no difference in the HR following vagal blockade.

Animals↗

Use of a closed-airway suctioning system during anesthesia.

We evaluated the efficacy of a closed airway suctioning (CAS) system in sixteen ASA Class I-II patients undergoing surgery of the extremities. All patients were anesthetized with 50% N2O and oxygen with adequate halogenated anesthesia. Full muscle relaxation was provided and all patients were ventilated with an anesthesia volume controlled ventilator. Endotracheal suctioning without preoxygenation was performed during anesthesia in randomly selected patients by either the CAS or the standard suctioning (SS) technique with a 30 minute rest period between suctioning. Both CAS and SS, used 14Fr catheters, were applied intermittently for 15 seconds at (-)150 mmHg suctioning pressure. SaO2 was continuously monitored throughout the suction period by a pulse oximeter. Arterial blood gas sample was drawn before each suction and 30 sec., 1 min, 3 min, 5 min, 10 min, 15 min, 30 min afterwards. No alteration of SaO2 or PaO2 was noted during CAS but significant lowering of PaO2 was noted for SS at the 30 seconds and 1 minutes post-suctional points. Potential advantages of CAS include: 1) PEEP can be maintained during suctioning. 2) Operating room pollution is minimized. 3) Accidental contamination of both the patient and the anesthesiologist can be prevented. 4) Time is saved during frequent intraoperative suctioning as no preoxygenation is required. 5) There is no need to turn off the anesthetic gases. We conclude that as CAS can maintain steady PaO2 during airway suctioning, it may be a better alternative for repeated intraoperative suctioning.

Adult↗

A bench test evaluation of a neonatal closed tracheal suction system.

We tested the hypothesis that a possible mechanism for reduced hypoxia during suctioning with closed tracheal suction systems (CTSS) is the provision of uninterrupted gas delivery and the maintenance of airway pressures. This was accomplished by using a neonatal ventilator and test lung model to permit the insertion of a CTSS (with and without suction applied), measurements of inspiratory and end-expiratory airway pressures proximal and distal to the endotracheal tube (ETT) and measurements of inspired and expired tidal volumes (sampled distal to the ETT). An 8 Fr CTSS was evaluated with 4.5, 4.0, and 3.5 mm ETT, and a 6 Fr CTSS with a 3.5, 3.0, and 2.5 mm ETT. We found that catheter placement without suction caused no changes in proximal airway pressures but distal peak inspiratory pressures decreased as the relationship between suction catheter size and ETT lumen increased, while distal end-expiratory pressures were unchanged. Similarly, distal tidal volumes progressively decreased as the size of the suction catheter occupied more of the ETT lumen. During suctioning with the 6 Fr catheter, proximal airway pressures were virtually unchanged; however, as ETT size decreased, distal airway pressures also decreased. The application of suction only modestly augmented the substantial decrement in measured tidal volumes when compared to catheter insertion alone. For the 8 Fr catheter, suction markedly reduced both proximal and distal airway pressures and tidal volumes. We conclude that the use of the CTSS tested in this neonatal ventilator/test lung model does not preserve continuity of volume or pressure delivery during suction procedures; therefore these cannot be the sole explanation for the reported reduction in suction related hypoxia.

Catheterization↗

Continuous gastric suctioning decreases measured esophageal temperature during general anesthesia.

OBJECTIVE: This study sought to determine whether continuous gastric suctioning influences esophageal temperature measurements. METHODS: This study evaluated 21 patients scheduled for extremity or lower abdominal surgery. After induction of general endotracheal anesthesia, an orogastric tube, and esophageal and nasopharyngeal temperature probes were placed in functional positions. Baseline esophageal (Tes) and nasopharyngeal (Tnas) temperatures were recorded and the orogastric tube was placed on continuous suction. After the first 11 patients (Group I) were studied, 10 additional patients (Group II) were studied with more frequent data collection to improve the time resolution of temperature changes. Temperatures were recorded for patients in Group I at 2 and 10 min with suctioning and 10 min after cessation of suctioning. In Group II, temperatures were recorded at 1, 2, 5 and 10 min with suctioning and 10 min after cessation of suctioning. Analysis of data was performed using repeated measures analysis of variance and paired t-tests with the Bonferroni correction. RESULTS: In Group I, Tes decreased significantly from 35.9 +/- 0.2 degrees C (mean +/- SE) to 35.1 +/- 0.4 degrees C at 2 min and 34.8 +/- 0.3 degrees C at 10 min of suctioning (p < 0.01). Ten minutes after cessation of suctioning, Tes was not significantly different from the baseline measurement. Tnas did not change significantly over the 20 min observation period. In Group II, Tes continually decreased from 36.2 +/- 0.1 degrees C to 34.8 +/- 0.3 degrees C after 10 min of suctioning (p < 0.006) and returned to near baseline 10 min after cessation of suctioning. There was no significant change in Tnas over the 20 min observation period. CONCLUSION: We conclude that continuous gastric suctioning decreases esophageal temperature measurements. This phenomenon should be recognized as an artifactual change in esophageal temperature and not a reflection of core temperature.

Adolescent↗

Endotracheal suctioning: from principles to practice.

OBJECTIVE: This paper aims to highlight the physical principles of pressure and flow dynamics underlying endotracheal suctioning, to demonstrate these on a simple illustrative model and to discuss the clinical implications of these principles for paediatric practice. DESIGN: Prospective in vitro study. SETTING: Paediatric intensive care unit of a tertiary, academic hospital. MEASUREMENTS AND MAIN RESULTS: The peak pressure change (DeltaP) obtained in a "bag-in-box" model was recorded during suctioning, using different combinations of endotracheal tube (ETT) and catheter sizes, different suction pressures and techniques. Suction was also performed on three different consistencies of gelatine, using a range of suction catheter sizes and vacuum pressures. The mass of gelatine suctioned per second was calculated. A large DeltaP was measured when using neonatal-sized ETTs. There was a linear relationship (r=0,8, p<0.05) between DeltaP and the ratio of external catheter area to area difference (internal ETT area-external catheter area). Significantly greater DeltaP was measured when using a short versus long suction catheter ( p<0.001) and when applying suction for longer duration ( p<0,001) and with higher vacuum pressures ( p<0.05). The amount of mucus suctioned in a given time was related to catheter size, suction pressure and mucus density. CONCLUSION: Applied clinically, these results indicate that intrapulmonary pressure changes generated by the endotracheal suctioning of intubated neonates are likely to be considerable, possibly translating into loss of lung volume.

Catheterization↗

Apical suction leads to severe ischemia of the ventricular apex.

OBJECTIVE: Apical suction devices allow displacement of the heart in off-pump coronary artery surgery. However, high vacuum pressure may injure the suctioned myocardium. It has been demonstrated that partial pressure of oxygen in the myocardium (ptiO(2)) is a sensitive and rapid indicator of myocardial ischemia. The purpose of this study is to evaluate the effect of apical suction on the ptiO(2) as an indirect measure of myocardial perfusion of the ventricular apex. METHODS: Twenty-six patients undergoing elective off-pump coronary surgery were studied. Intramyocardial ptiO(2) was continuously measured using a flexible catheter microprobe (Licox GMS mbH, Kiel, Germany). Patients were divided into two groups. In one group (Group A; n=14), the microprobe was intraoperatively inserted into the myocardium of the left ventricular apex. In the second group (Group B; n=12), the probe was inserted in the anterior wall of the left ventricle. Intramyocardial ptiO(2) monitoring was made with the heart in the resting position and after placing the apical suction device. RESULTS: In Group A, basal ptiO(2) was 15.3+/-7.4 mmHg. One minute after placing the apical suction device, the ptiO(2) significantly decreased to 2.3+/-1 mmHg (p<0.001). A progressive increase of ptiO(2) was observed immediately after the Xpose suction device was removed. ptiO(2) was 13.6+/-9.1 mmHg 5 min after releasing the suction cup and increased to 27.2+/-12.6 mmHg 20 min later. In Group B, basal ptiO(2) was 17+/-10.3 mmHg. No significant changes were observed in Group B after placing and removing the suction cup. CONCLUSIONS: Apical suction devices lead to severe ischemia of the suctioned myocardium. Collapse of coronary vessels due to vacuum pressure is a possible mechanism. Reperfusion occurs immediately after removing the suction cup and a significant reactive hyperemia is observed.

Aged↗

Hemodynamic effects of cardiotomy suction blood.

OBJECTIVE: Cardiac surgery induces a systemic inflammatory activation, which in severe cases is associated with peripheral vasodilation and hypotension. Cardiotomy suction blood contains high levels of inflammatory mediators, but the effect of cardiotomy suction blood on the vasculture is unknown. We investigated the effect of cardiotomy suction blood on systemic vascular resistance in vivo and whether cell-saver processing of suction blood affects the vascular response. METHODS: Twenty-five patients undergoing coronary surgery (mean age, 68 +/- 2 years; 80% men) were included in a prospective randomized study. The patients were randomized to retransfusion of cell-saver processed (n = 13) or cell-saver unprocessed (n = 12) suction blood during full cardiopulmonary bypass. Mean arterial blood pressure was continuously registered during retransfusion, and systemic vascular resistance was calculated. Plasma concentrations of tumor necrosis factor alpha, interleukin 6, and complement factor C3a were measured in suction blood. RESULTS: Retransfusion of cardiotomy suction blood induced a transient reduction in systemic vascular resistance in all patients. The peak reduction was significantly less pronounced in the group receiving cell-saver processed blood (-12% +/- 2% vs -28% +/- 3%, P = .001). There was a significant correlation between tumor necrosis factor alpha concentration in retransfused cardiotomy suction blood and peak reduction of systemic vascular resistance (r = 0.60, P = .002). CONCLUSIONS: The results suggest cardiotomy suction blood is vasoactive and might influence vascular resistance and blood pressure during cardiac surgery. The observed vasodilation is proportional to the inflammatory activation of suction blood and can be reduced by processing suction blood with a cell-saving device before retransfusion.

Aged↗

Post-suction recruitment manoeuvre restores lung function in healthy, anaesthetized pigs.

Endotracheal suction can cause partial lung collapse and hypoxia and alter lung mechanics. We investigated the effects of adding a recruitment manoeuvre directly after endotracheal suction to restore lung volume in volume-controlled ventilation and pressure-controlled ventilation modes. Five anaesthetized pigs were investigated. The effects of endotracheal suction with or without a recruitment manoeuvre were compared in random order. In volume-controlled ventilation, compliance decreased after suction from 33 +/- 5 to 26 +/- 6 ml x cmH2O(-1) (P<0.05), and 30 minutes later it remained decreased at 25 +/- 6 ml x cmH2O(-1). Venous admixture increased after suction from 5 +/- 2 to 8 +/- 4% (P<0.05), but had recovered at 30 minutes. In pressure-controlled ventilation, compliance decreased after suction from 34 +/- 3 to 25 +/- 7 ml x cmH2O(-1) (P<0.05), and 30 minutes later it remained decreased at 25 +/- 7 ml x cmH2O(-1). Venous admixture increased after suction from 5 +/- 2 to 13 +/- 7% (P<0.05), and had not recovered after 30 minutes, 10 +/- 4%. When a recruitment manoeuvre was applied directly after suction, no negative side-effects were registered in volume-controlled ventilation or pressure-controlled ventilation. We conclude that the impairment of lung mechanics and gas exchange induced by endotracheal suction can be prevented by a simple post-suction recruitment manoeuvre. Further studies are needed to identify a suitable suction recruitment manoeuvre in patients with diseased lungs.

Animals↗