Timo Seyfried

Background and Objectives: Electrocautery‐related surgical smoke removed together with the intraoperative blood collection through suction devices might be a potential hazard. The degree of contamination of the autologous blood despite cell recovery and its possible harm to the patient remain subjects of research.Materials and Methods: Two types of laboratory experiments and one clinical study were conducted. Initially, toluene was added to banked erythrocytes mixed with fresh frozen plasma. This reconstituted blood was processed using the autotransfusion device XTRA, and the elimination of toluene was calculated via gas chromatography (GC). In a second experiment, slices of pigskin were cut with electrocautery while dropping reconstituted blood onto the cauterization point. The resulting smoke and the blood were sucked into a cell salvage reservoir and washed with the XTRA. Samples from the reservoir and the product were analysed by GC. The average elimination rate was calculated. In a clinical study, blood samples were collected from the reservoir of the cell saver system during cardiac surgery and analysed likewise.Results: The autotransfusion device removed 92% of toluene from the processed blood. Other unidentified contaminants showed an elimination rate above 97.9%.Conclusion: Cell salvage devices significantly reduce the amount of contaminants in wound blood. Nevertheless, despite this highly effective detoxication, the remaining contaminants may still pose a potential risk to the patient.

Objectives: Robotic-assisted laparoscopic prostatectomy (RALP) is typically conducted in steep Trendelenburg position (STP). The aim of the study was to evaluate whether crystalloid administration and individual management of positive end-expiratory pressure (PEEP) improve peri- and post-operative pulmonary function in patients undergoing RALP. Design: Prospective randomised single-centre single-blinded explorative study. Setting: Patients were either allocated to a standard PEEP (5 cmH₂O) group or an individualised high PEEP group. Furthermore, each group was divided into a liberal and a restrictive crystalloid group (8 vs. 4 mL/kg/h predicted body weight). Individualised PEEP levels were determined by means of preoperative recruitment manoeuvre and PEEP titration in STP. Participants: Informed consent was obtained from 98 patients scheduled for elective RALP. Interventions: The following intraoperative parameters were analysed in each of the four study groups: ventilation setting (peak inspiratory pressure [PIP], plateau pressure, driving pressure [P_driv], lung compliance [LC] and mechanical power [MP]) and postoperative pulmonary function (bed-side spirometry). The spirometric parameters Tiffeneau index (FEV₁/FVC ratio) and mean forced expiratory flow (FEF_25–75) were measured pre- and post-operatively. Data are shown as mean ± standard deviation (SD), and groups were compared with ANOVA. A p-value of 2O]) showed intraoperative significantly higher PIP, plateau pressure and MP levels but significantly decreased P_driv and increased LC. On the first and second postoperative day, patients with individualised high PEEP levels had a significantly higher mean Tiffeneau index and FEF_25–75. Perioperative oxygenation and ventilation and postoperative spirometric parameters were not influenced by restrictive or liberal crystalloid infusion in either of the two respective PEEP groups. Conclusions: Individualised high PEEP levels (≥14 cmH₂O) during RALP improved intraoperative blood oxygenation and resulted in more lung-protective ventilation. Furthermore, postoperative pulmonary function was improved for up to 48 h after surgery in the sum of the two individualised high PEEP groups. Restrictive crystalloid infusion during RALP seemed to have no effect on peri- and post-operative oxygenation and pulmonary function.

Background: Sepsis is a leading cause of morbidity and mortality worldwide. Many patients suffering from sepsis are treated on intensive care units and many of them require mechanical ventilation under sedation or general anesthesia. Propofol, a drug used for these purposes, is known to interact with polymorphonuclear granulocytes (PMNs). Therefore, the aim of this study was to investigate the influence of propofol on PMN functions after experimental Gram-negative induced sepsis using lipopolysaccharide (LPS) stimulation. Methods: A total of 34 granulocyte-enriched samples were collected from healthy subjects. PMNs were isolated by density gradient centrifugation and incubated simultaneously with either 6 μg/mL or 60 μg/mL propofol, or none (control). Additionally, the experimental sepsis samples were incubated with either 40 pg/mL or 400 pg/mL LPS. Live cell imaging was conducted in order to observe granulocyte chemotactic migration, ROS production, and NETosis. Flow cytometry was used to analyze viability and antigen expression. Results: Propofol led to significantly reduced PMN track length (p < 0.001) and track speed (p < 0.014) after LPS-induced sepsis in a dose-dependent manner. NETosis (p = 0.018) and ROS production (p = 0.039) were accelerated by propofol without LPS incubation, indicating improved immune function. Propofol also ameliorated LPS-induced increased NETosis and ROS-production. Antigen expression for CD11b, CD62l and CD66b was unaffected by propofol. Conclusion: Propofol improves LPS-induced exaggerated PMN activation in an ex vivo model. Beneficial effects due to restored immune function in septic patients might be possible, but needs further investigation.

Introduction: Local anesthetics (LAs) are frequently used during anesthesia; however, they may influence granulocyte function which in turn could modify immune responses in the perioperative period. Therefore, the aim of this study was to investigate the impact of clinically used doses of bupivacaine and lidocaine on granulocyte function with regard to migration, reactive oxygen species (ROS) production, neutrophil extracellular traps (NETosis) formation, and viability. Methods: A total of 38 granulocyte-enriched samples from healthy subjects were obtained by whole blood lysis. Polymorphonuclear neutrophil (PMN) samples were incubated simultaneously with different concentrations of either bupivacaine (0.03– 3.16 mmol/L) or lidocaine (0.007– 14.21 mmol/L), or without drug (control). Live cell imaging was conducted in order to observe granulocyte chemotaxis, migration, ROS production, and NETosis. Flow cytometry was used to analyze viability and antigen expression. Results: The track length (TL) of PMNs exposed to bupivacaine concentrations of 0.16 mmol/L and above significantly decreased compared to the control. Low concentrations of lidocaine were associated with slight but significant increases in TL, whereas this changed with concentrations above 1.4 mmol/L, showing a significant decrease in TL. PMN incubated with bupivacaine concentrations of 1.58 mmol/L and above or lidocaine concentrations of at least 3.6 mmol/L showed no migration or chemotaxis at all. Time to onset of maximal ROS production and time for half-maximal NETosis decreased in a dose-dependent manner for both substances. Equipotency in NETosis induction was reached by bupivacaine (1.1 mmol/L) at significantly lower concentrations than lidocaine (7.96 mmol/L). Cell viability and oxidative burst were unaffected by LAs. Conclusion: Local anesthetics in clinically used doses ameliorate granulocyte defense mechanisms, thus indicating their potentially decisive effect during the perioperative period.

BACKGROUND: Autologous platelet‐rich plasma (PRP) can be used either to prevent platelets (PLTs) from lesions during extracorporeal circulation or for wound therapy, when processed into PLT gel. The aim of this study was to evaluate the PLT sequestration abilities of a new‐generation autotransfusion device.STUDY DESIGN AND METHODS: In this experimental study the discontinuous, new‐generation autotransfusion device XTRA was evaluated using fresh donor blood. The blood was processed in four different size bowls (X55, X125, X175, X225 [bowls' size in mL]) using the device's built‐in “PLT sequestration program.” PLT functionality was tested using aggregometry; for PLT activation, β‐thromboglobulin (β‐TG) and soluble P‐selectin levels were determined. Cell damage was assessed by a morphology score and hypotonic shock response. Additionally, PLTs were tested after 6 hours to identify storage lesions.RESULTS: Platelet recovery in the PRP ranged from 39% to 64% and averaged 6.2‐fold PLT enrichment as defined by the increase in PLT concentration. The preparation caused minimal cell damage and a decrease in cell function by only 10%, but a slight activation was observed amounting to 9% of the maximal β‐TG release. The efficiency of the preparation, represented by the PLT recovery rate, increased in a linear fashion with the increasing bowl sizes being tested. After 6 hours of storage the prepared PLTs showed an additional 9% loss in function, but only 4% decrease in viability.CONCLUSION: The autotransfusion device XTRA was capable of high‐quality perioperative PRP preparation, and the bowl size was found to have an influence on the efficiency of the preparation.

Background: Fat present during blood salvage in orthopaedic or cardiac surgery can pose a risk of fat embolism and should be eliminated before transfusion. Based on observations of central fat accumulation at the bottom of Latham bowls, a fat reduction program was developed using two volume displacements, where blood temporarily is removed and respun in the bowl to force the fat through the RBC sediment.Materials and methods: Pooled ABO‐matched RBC and FFP were adjusted to a haematocrit of 10%, and human fat tissue added to a concentration of 1·25 vol%. In six experiments, blood was processed with the new‐generation cell salvage device CS Elite in a newly developed fat reduction program in bowls of three sizes. Volumetric quantification of fat was performed after centrifugation of blood samples in Pasteur pipettes. From volumes, haematocrits and the concentrations of fat, RBC recovery and fat elimination rates were calculated.Results: Fat removal rates of 93·2 ± 2·8, 97·0 ± 2·1 and 99·6 ± 0·3% were observed with a 70‐ml, 125‐ml and 225‐ml bowl, respectively, and even higher rates when removal rates were calculated one cycle. At the same time, high RBC recovery and plasma elimination rates were maintained, not significantly different to the default program mode.Conclusion: Modifications in process parameters and sequence led to a fat reduction program that significantly improves fat removal with the Cell Saver Elite from 77·4 ± 5·1% in the default mode to an average of 98·6 ± 1·1%, yielding results equivalent to the continuous cell salvage system (C.A.T.S).

SUMMARY: Background and objectives: Cell salvage plays a key role in blood conservation. To maintain high performance, quality management is recommended. Accordingly, a new‐generation autotransfusion device was tested for its performance and compared with its predecessor. Two different calculations of quality parameters were applied.Materials and methods: In an experimental study, the continuous autotransfusion devices CATSmart and Continuous Autotransfusion System (C.A.T.S) plus were tested using banked blood adjusted to a haematocrit of 20% and anticoagulated with heparin 5 U/L. Test blood was processed using an emergency programme, a high‐quality programme/smart wash programme and a low‐volume wash programme. Samples were taken after the production of 200 mL of red blood cells (RBC) and after the final emptying of the separation chamber. In an additional set of tests, blood containing 1·25% fat was processed with both devices to examine fat removal.Results: Both devices demonstrated an equally high performance with regards to product hematocrit (Hct); RBC recovery; and elimination rates of protein, heparin and fat. The high fat elimination rate (>99·8%) reported for C.A.T.S plus was confirmed for CATSmart, regardless of the used programme. Samples taken during the ongoing process show a higher haematocrit and RBC recovery rate than samples taken after the final emptying of the separation chamber. Interface sensors were not affected by fat in the blood.Conclusions: The new‐generation autotransfusion device CATSmart is not inferior to its predecessor and shows high performance with regards to RBC recovery, plasma and fat elimination in all programme modes. Samples for quality controls should be taken during blood processing.