We investigated the relationship between the loaded pressure and flow rate in various catheters and the entire infusion line including the catheters, in several infusion solutions and packed red ...blood cells.
We connected the infusion line and catheter to the infusion solution and used an outer pressure bag or a compressor to pressurize the infusion solution bag to a pressure within the clinical (up to 450 mm Hg) or higher range (up to 1050 mm Hg). We approximated the relationship between the loaded pressure and flow rate in the entire infusion line including the catheter, versus the catheter alone, as a power function and compared the power numbers.
In the clinical pressure range of normal saline, the power numbers of the entire infusion line for the 24-, 22-, 20-, and 18-gauge catheters were 0.76, 0.82, 0.81, and 0.86, respectively, while those for the catheter alone were 0.67, 0.63, 0.56, and 0.44, respectively. In the higher pressure range of normal saline, the power numbers of the entire infusion line for the 24-, 22-, 20-, and 18-gauge catheters were 0.68, 0.70, 0.71, and 0.73, respectively, while those for the catheter alone were 0.62, 0.61, 0.59, and 0.58, respectively. As the power number of the entire infusion line was closer to 1.00 than the values of the catheter, the relation between the loaded pressure and the flow rate was more linear in the entire infusion line than that in the catheter. Similar results were obtained using packed red blood cells and 40% glycerin mixture in normal saline.
Regardless of the type of infusion solution or transfusion, the pressure-flow relationship in the catheter was nonlinear and not directly proportional. However, within the clinical pressure range (up to 450 mm Hg), the relationship between the flow rate and pressure in the entire infusion line was almost linear and proportional.
BACKGROUNDPatient blood management (PBM) can prevent preoperative anaemia, but little is known about practice in Europe.
OBJECTIVETo assess the pre and postoperative prevalence and perioperative ...management of anaemia in patients undergoing elective orthopaedic surgery in Europe.
DESIGNAn observational study; data were collected from patient records via electronic case report forms.
SETTINGSeventeen centres in six European countries. Centres were stratified according to whether they had a PBM programme or not.
PATIENTSOne thousand five hundred and thirty-four patients undergoing major elective hip, knee or spine surgery 49.9% hip, 37.2% knee, 13.0% spine; age 64.0 years (range 18 to 80), 61.3% female.
MAIN OUTCOME MEASURESPrevalence of preoperative (primary endpoint) and postoperative anaemia haemoglobin (Hb) <13 g dl (male), Hb <12 g dl (female), perioperative anaemia management, time to first blood transfusion and number of transfused units. Data are shown as mean (SD) or median (interquartile range).
RESULTSAnaemia prevalence increased from 14.1% preoperatively to 85.8% postoperatively. Mean Hb decrease was 1.9 (1.5) and 3.0 (1.3) g dl in preoperatively anaemic and nonanaemic patients, respectively (P < 0.001). In PBM (n = 7) vs. non-PBM centres, preoperative anaemia was less frequent (8.0 vs. 18.5%; P < 0.001) and iron status was assessed more frequently (ferritin 11.0 vs. 2.6%, transferrin saturation 11.0 vs. 0.1%; P < 0.001). Perioperative anaemia correction (mainly transfusion) was given to 34.3%. Intraoperatively, 14.8% of preoperatively anaemic and 2.8% of nonanaemic patients received transfusions units per patient2.4 (1.5) and 2.2 (1.4), median time to first intraoperative transfusion130 (88, 158) vs. 179 (135, 256) min; P < 0.001. Postoperative complications were more frequent in preoperatively anaemic vs. nonanaemic patients (36.9 vs. 22.2%; P = 0.009).
CONCLUSIONMost patients who underwent elective orthopaedic surgery had normal preoperative Hb levels but became anaemic after the procedure. Those who were anaemic prior to surgery had an increased intraoperative transfusion risk and postoperative complication rate. PBM measures such as iron status assessment and strategies to avoid transfusion are still underused in Europe.
OBJECTIVES
In cardiac surgery, the association between red blood cell (RBC) transfusion and clinical outcome is elusive. We investigated in a large cohort of patients who underwent isolated coronary ...artery bypass grafting (CABG) the effect of transfusion of 1–2 units of leucocyte-depleted RBCs on mortality and multiorgan failure.
METHODS
The investigation included all patients from July 2009 to June 2014 who underwent CABG at our institution and received no (n = 1478) or 1–2 units of RBCs (n = 1528). The primary end-point was 30-day mortality; secondary end-points were major organ dysfunction. A subgroup analysis assessed the effect of the duration of RBC storage on patient outcome. Statistical analysis was performed using propensity score (PS) adjustment.
RESULTS
The 30-day mortality rate was 0.3% in the RBC− group and 0.2% in the RBC+ group. Compared with the RBC− group, PS-adjusted odds ratio (OR) of 30-day mortality in the RBC+ group was 0.29 95% confidence interval (CI): 0.06–1.50; P = 0.14. PS-adjusted OR of a ‘prolonged intensive care unit (ICU) stay’ (>48 h) was significantly higher in the RBC+ group than in the RBC− group OR 1.49 (95% CI: 1.14–1.95); P = 0.004, but major clinical complications such as low cardiac output syndrome, stroke, haemofiltration, wound infection and prolonged mechanical ventilator support (>24 h) did not differ significantly between groups. Duration of blood storage was not independently associated with clinical outcome.
CONCLUSIONS
Our data do not indicate a transfusion-related increase in mortality and multiorgan failure in patients undergoing isolated CABG.
Purpose
This study was designed to optimize the latest generation venovenous (vv)-extracorporeal membrane oxygenation (ECMO)-circuit configuration and settings based on the evaluation of blood ...oxygenation and CO
2
removal determinants in patients with severe acute respiratory distress syndrome (ARDS) on ultraprotective mechanical ventilation.
Methods
Blood gases and hemodynamic parameters were evaluated after changing one of three ECMO settings, namely, circuit blood flow, FiO
2ECMO
(fraction of inspired oxygen in circuit), or sweep gas flow ventilating the membrane, while leaving the other two parameters at their maximum setting.
Results
Ten mechanically ventilated ARDS patients (mean age 44 ± 16 years; 6 males; mean hemoglobin 8.0 ± 1.8 g/dL) on ECMO for a mean of 9.0 ± 3.8 days) receiving femoro–jugular vv-ECMO were evaluated. vv-ECMO blood flow and FiO
2ECMO
determined arterial oxygenation. Decreasing the ECMO flow from its baseline maximum value (5.8 ± 0.8 L/min) to 40 % less (2.4 ± 0.3 L/min) significantly decreased mean PaO
2
(arterial oxygen tension; 88 ± 24 to 45 ± 9 mm Hg;
p
< 0.001) and SaO
2
(oxygen saturation; 97 ± 2 to 82 ± 10 %;
p
< 0.001). When the ECMO flow/cardiac output was >60 %, SaO
2
was always >90 %. Alternatively, the rate of sweep gas flow through the membrane lung determined blood decarboxylation, while PaCO
2
(arterial carbon dioxide tension) was unaffected when the ECMO blood flow and FiO
2ECMO
were reduced to <2.5 L/min and 40 %, respectively. In three additional patients evaluated before and after red blood cell transfusion, O
2
delivery increased after transfusion, allowing lower ECMO flows to reach adequate SaO
2
.
Conclusions
For severe ARDS patients receiving femoro–jugular vv-ECMO, blood flow was the main determinant of arterial oxygenation, while CO
2
elimination depended on sweep gas flow through the oxygenator. An ECMO flow/cardiac output >60 % was constantly associated with adequate blood oxygenation and oxygen transport and delivery.
The authors report on three patients who received full-face transplants in procedures aimed at functional restoration. Six months after transplantation, facial appearance and function were improved ...and glucocorticoids had been successfully withdrawn in all patients.
Facial transplantation is a single, complex operation intended to transform severely deformed features to near-normal appearance and function with the use of techniques that conventional plastic surgery cannot match.
1
Since 2005, a total of 18 patients have received transplants with promising results.
2
–
7
Most facial transplantations have been designed to restore partial-face defects; full-face transplantations include the forehead, eyelids, nose, lips, chin, and cheeks,
8
,
9
with or without underlying bone. Full-face transplantation has been considered nearly impossible because of the complexity of the blood supply as well as ethical, psychological, and social implications. We report our initial experience in full-face . . .
Summary
The decision to transfuse a neonate can be approached by addressing a series of questions that cover the cause of anaemia, alternatives to transfusion, the need for transfusion and the risks. ...Recent clinical trials of red cell transfusions have started to inform evidence‐based transfusion practice, but have raised uncertainties about neurological outcomes when policies advocating use of fewer red cell transfusions at lower haemoglobin concentration (Hb) thresholds were tested. Red cell transfusions should be considered when the Hb <120 g/l for premature neonates requiring mechanical ventilation support, with lower thresholds applying for oxygen‐dependent neonates not requiring ventilation or for late anaemia (Hb <70–100 g/l, depending on gestational and post‐natal age). There is no recent high quality evidence to inform thresholds for prophylactic platelet transfusions in stable non‐bleeding premature neonates with platelet count levels of 50 × 109/l, although common practice has become more restrictive, using lower safe thresholds for platelet transfusion between 20 and 30 × 109/l. A more appropriate transfusion strategy for fresh frozen plasma (FFP) in neonates is one that emphasizes the therapeutic use of FFP in the face of bleeding, rather than prophylactic use in stable non‐bleeding neonates who often have mild to moderate apparent abnormalities of standard coagulation tests, after allowing for appropriate reference ranges.
Paediatric-preoperative anaemia management is challenging in settings where clinical judgment is used to diagnose anaemia owing to a lack of timely, affordable preoperative haemoglobin testing. We ...analysed anaemia management in such a setting after the introduction of point-of-care bedside haemoglobin testers.
1033 children who underwent surgery at a hospital in Bangladesh were included in this study. 569 underwent major surgery, and 464 underwent minor surgery and belonged to predominantly ASA category 1 or 2.
940/1033 children underwent preoperative anaemia testing. Average haemoglobin was 11.7 g/dL. 103/1033 children were deemed clinically anaemic. However, 285 children were found to have anaemia based on bedside testing. Sensitivity of clinical judgement was 33.68% (95 % CI 28.22%-39.49%), and the specificity was 99.08% (95 % CI 98.02%-99.66%). 63/1033 had preoperative anaemia treatment, of whom 60 underwent transfusion. Subgroup analysis of children with haemoglobin <10 g/dL (n = 124) was done to compare conservative vs liberal transfusion strategy. 43/124 of this subset was transfused. Average length of stay for those transfused was 11.7 days, and those who weren't was 9.9 days (p = 0.087). 4 patients in the transfused subgroup required post-op ICU, and only 1 patient in the conservatively managed arm required ICU (p = 0.048).
This study demonstrates the positive impact of bedside haemoglobin testers as they have resulted in a significantly higher proportion of children diagnosed with anaemia at a fraction of the cost and logistics involved in laboratory testing. Further research on haemoglobin thresholds is required to understand the safety and long-term impact of restrictive transfusion in the surgical context.
2c (Grading as per the Oxford Centre for Evidence Based Medicine).
Randomized clinical trial findings support decreased red blood cell (RBC) transfusion and short-term tolerance of in-hospital anemia. However, long-term outcomes related to changes in transfusion ...practice have not been described.
To describe the prevalence of anemia at and after hospital discharge and associated morbidity and mortality events.
Retrospective cohort study.
Integrated health care delivery system with 21 hospitals serving 4 million members.
445 371 surviving adults who had 801 261 hospitalizations between January 2010 and December 2014.
Hemoglobin levels and RBC transfusion, rehospitalization, and mortality events within 6 months of hospital discharge. Generalized estimating equations were used to examine trends over time, accounting for correlated observations and patient-level covariates.
From 2010 to 2014, the prevalence of moderate anemia (hemoglobin levels between 7 and 10 g/dL) at hospital discharge increased from 20% to 25% (P < 0.001) and RBC transfusion declined by 28% (39.8 to 28.5 RBC units per 1000 patients; P < 0.001). The proportion of patients whose moderate anemia had resolved within 6 months of hospital discharge decreased from 42% to 34% (P < 0.001), and RBC transfusion and rehospitalization within 6 months of hospital discharge decreased from 19% to 17% and 37% to 33%, respectively (P < 0.001 for both). During this period, the adjusted 6-month mortality rate decreased from 16.1% to 15.6% (P = 0.004) in patients with moderate anemia, in parallel with that of all others.
Possible unmeasured confounding.
Anemia after hospitalization increased in parallel with decreased RBC transfusion. This increase was not accompanied by a rise in subsequent RBC use, rehospitalization, or mortality within 6 months of hospital discharge. Longitudinal analyses support the safety of practice recommendations to limit RBC transfusion and tolerate anemia during and after hospitalization.
National Heart, Lung, and Blood Institute.
Sepsis is one of the major causes of death worldwide, and is the host response to infection which renders our organs malfunctioning. Insufficient tissue perfusion and oxygen delivery have been ...implicated in the pathogenesis of sepsis-related organ dysfunction, making transfusion of packed red blood cells (pRBCs) a reasonable treatment modality. However, clinical trials have generated controversial results. Even the notion that transfused pRBCs increase the oxygen-carrying capacity of blood has been challenged. Meanwhile, during sepsis, the ability of our tissues to utilize oxygen may also be reduced, and the increased blood concentrations of lactate may be the results of strong inflammation and excessive catecholamine release, rather than impaired cell respiration. Leukodepleted pRBCs more consistently demonstrated improvement in microcirculation, and the increase in blood viscosity brought about by pRBC transfusion helps maintain functional capillary density. A restrictive strategy of pRBC transfusion is recommended in treating septic patients.
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