Intraoperative blood loss and blood transfusion requirements in patients undergoing orthognathic surgery

Procedures for the surgical correction of dentofacial deformities may produce important complications, whether due to the potential for vascular injury or to prolonged surgery, both of which may lead to severe blood loss. Fluid replacement with crystalloid, colloid, or even blood products may be required. The aim of this study was to assess blood loss and transfusion requirements in 45 patients (18 males and 27 females; mean age 29.29 years, range 16-52 years) undergoing orthognathic surgery, assigned to one of two groups according to procedure type-rapid maxillary expansion or double-jaw orthognathic surgery. Preoperative hemoglobin and hematocrit levels and intraoperative blood loss were measured. There was a substantial individual variation in pre- and postoperative hemoglobin values (10.3-17 and 8.8-15.4 g/dL, respectively; p < 0.05). Mean hematocrit values were 41.53 % preoperatively (range 31.3-50.0 %) and 36.56 % postoperatively (range 25-43.8 %) (p < 0.05). Mean blood loss was 274.60 mL (range 45-855 mL). Only two patients required blood transfusion. Although blood loss and transfusion requirements were minimal in the present study, surgical teams should monitor the duration of surgery and follow meticulous protocols to minimize the risks.

500 ml of blood loss does not decrease non-invasive tissue oxygen saturation (StO2) as measured by near infrared spectroscopy - A hypothesis generating pilot study in healthy adult women

Background The goal when resuscitating trauma patients is to achieve adequate tissue perfusion. One parameter of tissue perfusion is tissue oxygen saturation (StO2), as measured by near infrared spectroscopy. Using a commercially available device, we investigated whether clinically relevant blood loss of 500 ml in healthy volunteers can be detected by changes in StO2 after a standardized ischemic event. Methods We performed occlusion of the brachial artery for 3 minutes in 20 healthy female blood donors before and after blood donation. StO2 and total oxygenated tissue hemoglobin (O2Hb) were measured continuously at the thenar eminence. 10 healthy volunteers were assessed in the same way, to examine whether repeated vascular occlusion without blood donation exhibits time dependent effects. Results Blood donation caused a substantial decrease in systolic blood pressure, but did not affect resting StO2 and O2Hb values. No changes were measured in the blood donor group in the reaction to the vascular occlusion test, but in the control group there was an increase in the O2Hb rate of recovery during the reperfusion phase. Conclusion StO2 measured at the thenar eminence seems to be insensitive to blood loss of 500 ml in this setting. Probably blood loss greater than this might lead to detectable changes guiding the treating physician. The exact cut off for detectable changes and the time effect on repeated vascular occlusion tests should be explored further. Until now no such data exist.

The impact of pelvic venous pressure on blood loss during open radical cystectomy and urinary diversion: Results from a secondary analysis of a randomized clinical trial

PURPOSE Blood loss and blood substitution are associated with higher morbidity after major abdominal surgery. During major liver resection, low local venous pressure, has been shown to reduce blood loss. Ambiguity persists concerning the impact of local venous pressure on blood loss during open radical cystectomy. We aimed to determine the association between intraoperative blood loss and pelvic venous pressure (PVP) and determine factors affecting PVP. MATERIAL AND METHODS In the frame of a single-center, double-blind, randomized trial, PVP was measured in 82 patients from a norepinephrine/low-volume group and in 81 from a control group with liberal hydration. For this secondary analysis, patients from each arm were stratified into subgroups with PVP <5 mmHg or ≥5 mmHg measured after cystectomy (optimal cut-off value for discrimination of patients with relevant blood loss according to the Youden's index). RESULTS Median blood loss was 800 ml [range: 300-1600] in 55/163 patients (34%) with PVP <5 mmHg and 1200 ml [400-3000] in 108/163 patients (66%) with PVP ≥5 mmHg; (P<0.0001). A PVP <5 mmHg was measured in 42/82 patients (51%) in the norepinephrine/low-volume group and 13/81 (16%) in the control group (P<0.0001). PVP dropped significantly after removal of abdominal packing and abdominal lifting in both groups at all time points (at begin and end of pelvic lymph node dissection, end of cystectomy) (P<0.0001). No correlation between PVP and central venous pressure could be detected. CONCLUSIONS Blood loss was significantly reduced in patients with low PVP. Factors affecting PVP were fluid management and abdominal packing.

New perioperative fluid and pharmacologic management protocol results in reduced blood loss, faster return of bowel function, and overall recovery.

Cystectomy and urinary diversion have high morbidity, and strategies to reduce complications are of utmost importance. Epidural analgesia and optimized fluid management are considered key factors contributing to successful enhanced recovery after surgery. In colorectal surgery, there is strong evidence that an intraoperative fluid management aiming for a postoperative zero fluid balance results in lower morbidity including a faster return of bowel function. Recently, a randomized clinical trial focusing on radical cystectomy demonstrated that a restrictive intraoperative hydration combined with a concomitant administration of norepinephrine reduced intraoperative blood loss, the need for blood transfusion and morbidity. The purpose of this review is to highlight specific anesthesiological aspects which have been shown to improve outcome after RC with urinary diversion.

Effects of dialysis modality on blood loss, bleeding complications and transfusion requirements in critically ill patients with dialysis-dependent acute renal failure.

Blood loss and bleeding complications may often be observed in critically ill patients on renal replacement therapies (RRT). Here we investigate procedural (i.e. RRT-related) and non-procedural blood loss as well as transfusion requirements in regard to the chosen mode of dialysis (i.e. intermittent haemodialysis [IHD] versus continuous veno-venous haemofiltration [CVVH]). Two hundred and fifty-two patients (122 CVVH, 159 male; aged 61.5±13.9 years) with dialysis-dependent acute renal failure were analysed in a sub-analysis of the prospective randomised controlled clinical trial-CONVINT-comparing IHD and CVVH. Bleeding complications including severity of bleeding and RRT-related blood loss were assessed. We observed that 3.6% of patients died related to severe bleeding episodes (between group P=0.94). Major all-cause bleeding complications were observed in 23% IHD versus 26% of CVVH group patients (P=0.95). Under CVVH, the rate of RRT-related blood loss events (57.4% versus 30.4%, P=0.01) and mean total blood volume lost was increased (222.3±291.9 versus 112.5±222.7 ml per patient, P <0.001). Overall, transfusion rates did not differ between the study groups. In patients with sepsis, transfusion rates of all blood products were significantly higher when compared to cardiogenic shock (all P <0.01) or other conditions. In conclusion, procedural and non-procedural blood loss may often be observed in critically ill patients on RRT. In CVVH-treated patients, procedural blood loss was increased but overall transfusion rates remained unchanged. Our data show that IHD and CVVH may be regarded as equivalent approaches in critically ill patients with dialysis-dependent acute renal failure in this regard.

Short-Term Carbohydrate-Restricted Diet for Weight Loss in Severely Obese Women

Weight loss in bariatric pre-surgery period reduces surgical complications, surgery time, blood loss, and length of hospital stay. Carbohydrate-restricted diets have been used as an alternative for weight loss. We tested the efficacy of a low-calorie carbohydrate-restricted diet (RD) for short-term weight loss in women with severe obesity and evaluate its metabolic effects in relation to a conventional low-calorie diet (CD). The subjects received a 1,200-kcal diet with or without carbohydrate restriction for a period of 1 week in the hospital. Nineteen obesity class III women were distributed into two groups: experimental (n = 10) and control (n = 9). The following variables were assessed at the beginning and end of the study: anthropometric measurements, body composition, resting energy expenditure, substrate oxidation, and biochemical tests. Compared with CD, RD led to larger weight loss (2.6 and 4.4 kg, respectively; p = 0.01) and waist circumference reduction (p < 0.01). Among the assessed biochemical indicators, only plasma and urine acetone levels were different (p < 0.01); higher values were found in the experimental group with no symptoms and other diet-related complaints. There was also a significant decrease in triglycerides and carbohydrate oxidation, as well as a significant enhancement in lipid oxidation in the RD group. Short-term RD was more efficient than CD regarding quick weight loss and waist circumference reduction, which may favor gastroplasty. Also, RD did not lead adverse metabolic effects.

Loss of Memo, a novel FGFR regulator, results in reduced lifespan.

Memo is a widely expressed 33-kDa protein required for heregulin (HRG)-, epidermal growth factor (EGF)-, and fibroblast growth factor (FGF)-induced cell motility. Studies in mouse embryonic fibroblasts, wild-type or knockout for Memo, were performed to further investigate the role of Memo downstream of FGFR. We demonstrated that Memo associates with the FGFR signalosome and is necessary for optimal activation of signaling. To uncover Memo's physiological role, Memo conditional-knockout mice were generated. These animals showed a reduced life span, increased insulin sensitivity, small stature, graying hair, alopecia, kyphosis, loss of subcutaneous fat, and loss of spermatozoa in the epididymis. Memo-knockout mice also have elevated serum levels of active vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D), and calcium compared to control littermates expressing Memo. In summary, the results from in vivo and in vitro models support the hypothesis that Memo is a novel regulator of FGFR signaling with a role in controlling 1,25(OH)2D production and normal calcium homeostasis.

Recovery of postoperative visual loss following treatment of severe anaemia.

A 29-year-old pregnant woman noted acute visual loss following emergent Caesarean section complicated by excessive uterine bleeding. Postoperative visual acuity was count fingers in both eyes. Funduscopic changes were consistent with a diagnosis of anaemia-associated ischaemic optic neuropathy and retinopathy. One month later, because of persistent anaemia and poor visual recovery, blood transfusion was given. Following transfusion, the patient's vision improved over the next 6 months. In an otherwise healthy patient, visual loss associated with postoperative blood loss may still be partially reversible with correction of the anaemia, even after a delayed period of time.

Smart suction device for less blood trauma: a comparison with Cell Saver.

OBJECTIVE: The major source of hemolysis during cardiopulmonary bypass remains the cardiotomy suction and is primarily due to the interaction between air and blood. The Smart suction system involves an automatically controlled aspiration designed to avoid the mixture of blood with air. This study was set-up to compare this recently designed suction system to a Cell Saver system in order to investigate their effects on blood elements during prolonged intrathoracic aspiration. METHODS: In a calf model (n=10; mean weight, 69.3+/-4.5 kg), a standardized hole was created in the right atrium allowing a blood loss of 100 ml/min, with a suction cannula placed into the chest cavity into a fixed position during 6 h. The blood was continuously aspirated either with the Smart suction system (five animals) or the Cell Saver system (five animals). Blood samples were taken hourly for blood cell counts and biochemistry. RESULTS: In the Smart suction group, red cell count, plasma protein and free hemoglobin levels remained stable, while platelet count exhibited a significant drop from the fifth hour onwards (prebypass: 683+/-201*10(9)/l, 5 h: 280+/-142*10(9)/l, P=0.046). In the Cell Saver group, there was a significant drop of the red cell count from the third hour onwards (prebypass: 8.6+/-0.9*10(12)/l, 6 h: 6.3+/-0.4*10(12)/l, P=0.02), of the platelet count from the first hour onwards (prebypass: 630+/-97*10(9)/l, 1 h: 224+/-75*10(9)/l, P<0.01), and of the plasma protein level from the first hour onwards (prebypass: 61.7+/-0.6 g/l, 1 h: 29.3+/-9.1 g/l, P<0.01). CONCLUSIONS: In this experimental set-up, the Smart suction system avoids damage to red cells and affects platelet count less than the Cell Saver system which induces important blood cell destruction, as any suction device mixing air and blood, as well as severe hypoproteinemia with its metabolic, clotting and hemodynamic consequences.

[Measures for allogeneic blood conservation in surgery]

The aim of all efforts to reduce the need of allogeneic blood transfusions is to avoid associated risks. There should particularly be a favourable effect according to the rate of transfusion-transmitted virus infections and immunological side-effects. The acceptance of an individually adjusted lowest haematocrit level and the minimisation of intra-operative blood loss by the application of optimal surgical techniques are among the most essential strategies to reduce or even avoid allogeneic blood transfusions. In addition the following interventions are generally accepted: Preoperative autologous blood donation, where appropriate supported by erythropoietin Preoperative haemodilution, where appropriate supported by erythropoietin Intra- and postoperative blood salvage Topical or systemic pharmacologic interventions to accelerate haemostasis Controlled hypotension Efficacy and indication of the different measures always depend on the individual circumstances of the specific patient. Therefore one should develop an individual approach for every case. In this context the most important subjects are an optimal coordination and if required an appropriate combination of the discussed methods. Algorithms which preoperatively allow approximate calculation of expected transfusion need may be a meaningful tool to facilitate blood conservation planning. However, at the same time one must consider that all strategies to reduce allogeneic transfusion needs are also associated with particular risks. Therefore one has to weigh carefully the pros and cons prior to their application, including the possible alternative of allogeneic transfusion in one's decision making process.

Decreased factor XIII availability for thrombin and early loss of clot firmness in patients with unexplained intraoperative bleeding

To explore relevant changes in unexplained intraoperative bleeding, we evaluated elements of the final steps of the coagulation cascade in 226 consecutive patients undergoing elective surgery. Patients were stratified for the occurrence of unexplained intraoperative bleeding according to predefined criteria. Twenty patients (8.8%) developed unexplained bleeding. The median intraoperative blood loss was 1350 mL (bleeders) and 400 mL (nonbleeders) (P < 0.001). Fibrinogen and Factor XIII (F. XIII) were more rapidly consumed in bleeders (P < 0.001). Soluble fibrin formation (fibrin monomer) was increased in bleeders throughout surgery (P < or = 0.014). However, F. XIII availability per unit thrombin generated was significantly decreased in bleeders before, during, and after surgery (P < or = 0.051). Computerized thrombelastography showed a parallel, significant reduction in clot firmness. We suggest that mild preexisting coagulopathy is not rare in surgical patients and probably can result in clinically relevant intraoperative bleeding. This hemostatic disorder shows impaired clot firmness, probably secondary to decreased cross-linking (due to a loss of F. XIII, both in absolute measures and per unit thrombin generated). We suggest that the application of F. XIII might be worthwhile to test in a prospective clinical trial to increase clot firmness in patients at risk for this intraoperative coagulopathy.

Intraoperative Continuous Norepinephrine Infusion Combined with Restrictive Deferred Hydration Significantly Reduces the Need for Blood Transfusion in Patients Undergoing Open Radical Cystectomy: Results of a Prospective Randomised Trial

BACKGROUND Open radical cystectomy (ORC) is associated with substantial blood loss and a high incidence of perioperative blood transfusions. Strategies to reduce blood loss and blood transfusion are warranted. OBJECTIVE To determine whether continuous norepinephrine administration combined with intraoperative restrictive hydration with Ringer's maleate solution can reduce blood loss and the need for blood transfusion. DESIGN, SETTING, AND PARTICIPANTS This was a double-blind, randomised, parallel-group, single-centre trial including 166 consecutive patients undergoing ORC with urinary diversion (UD). Exclusion criteria were severe hepatic or renal dysfunction, congestive heart failure, and contraindications to epidural analgesia. INTERVENTION Patients were randomly allocated to continuous norepinephrine administration starting with 2 μg/kg per hour combined with 1 ml/kg per hour until the bladder was removed, then to 3 ml/kg per hour of Ringer's maleate solution (norepinephrine/low-volume group) or 6 ml/kg per hour of Ringer's maleate solution throughout surgery (control group). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Intraoperative blood loss and the percentage of patients requiring blood transfusions perioperatively were assessed. Data were analysed using nonparametric statistical models. RESULTS AND LIMITATIONS Total median blood loss was 800 ml (range: 300-1700) in the norepinephrine/low-volume group versus 1200 ml (range: 400-2800) in the control group (p<0.0001). In the norepinephrine/low-volume group, 27 of 83 patients (33%) required an average of 1.8 U (±0.8) of packed red blood cells (PRBCs). In the control group, 50 of 83 patients (60%) required an average of 2.9 U (±2.1) of PRBCs during hospitalisation (relative risk: 0.54; 95% confidence interval [CI], 0.38-0.77; p=0.0006). The absolute reduction in transfusion rate throughout hospitalisation was 28% (95% CI, 12-45). In this study, surgery was performed by three high-volume surgeons using a standardised technique, so whether these significant results are reproducible in other centres needs to be shown. CONCLUSIONS Continuous norepinephrine administration combined with restrictive hydration significantly reduces intraoperative blood loss, the rate of blood transfusions, and the number of PRBC units required per patient undergoing ORC with UD.

A novel blood-sparing agent in cardiac surgery? First in-patient experience with the synthetic serine protease inhibitor MDCO-2010: a phase II, randomized, double-blind, placebo-controlled study in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass

BACKGROUND Antifibrinolytics have been used for 2 decades to reduce bleeding in cardiac surgery. MDCO-2010 is a novel, synthetic, serine protease inhibitor. We describe the first experience with this drug in patients. METHODS In this phase II, double-blind, placebo-controlled study, 32 patients undergoing isolated primary coronary artery bypass grafting with cardiopulmonary bypass were randomly assigned to 1 of 5 increasing dosage groups of MDCO-2010. The primary aim was to evaluate pharmacokinetics (PK) with assessment of plasmatic concentrations of the drug, short-term safety, and tolerance of MDCO-2010. Secondary end points were influence on coagulation, chest tube drainage, and transfusion requirements. RESULTS PK analysis showed linear dosage-proportional correlation between MDCO-2010 infusion rate and PK parameters. Blood loss was significantly reduced in the 3 highest dosage groups compared with control (P = 0.002, 0.004 and 0.011, respectively). The incidence of allogeneic blood product transfusions was lower with MDCO-2010 4/24 (17%) vs 4/8 (50%) in the control group. MDCO-2010 exhibited dosage-dependent antifibrinolytic effects through suppression of D-dimer generation and inhibition of tissue plasminogen activator-induced lysis in ROTEM analysis as well as anticoagulant effects demonstrated by prolongation of activated clotting time and activated partial thromboplastin time. No systematic differences in markers of end organ function were observed among treatment groups. Three patients in the MDCO-2010 groups experienced serious adverse events. One patient experienced intraoperative thrombosis of venous grafts considered possibly related to the study drug. No reexploration for mediastinal bleeding was required, and there were no deaths. CONCLUSIONS This first-in-patient study demonstrated dosage-proportional PK for MDCO-2010 and reduction of chest tube drainage and transfusions in patients undergoing primary coronary artery bypass grafting. Antifibrinolytic and anticoagulant effects were demonstrated using various markers of coagulation. MDCO-2010 was well tolerated and showed an acceptable initial safety profile. Larger multi-institutional studies are warranted to further investigate the safety and efficacy of this compound.