Intraoperative blood loss during orthognathic surgery is predicted by thromboelastography

Thromboelastography in the Perioperative Period: A Literature Review

Assessing coagulation status is essential for prompt intervention to reduce morbidity and mortality related to bleeding and thrombotic complications during the perioperative period. Traditional coagulation tests such as platelet count, activated partial thromboplastin time (aPTT), prothrombin time (PT), international normalized ratio (INR), and activated clotting time (ACT) provide only static evaluation. These tests are not designed for assessment of dynamically changing coagulation conditions during the perioperative time. However, viscoelastic coagulation testing such as thromboelastography (TEG) produces a rapid numerical and graphical representation that helps to detect and direct targeted hemostatic therapy. Searching the literature through PubMed, Medline, Ovid, CINAHL, and ClinicalTrials.gov we retrieved 210 studies, which represent the use of TEG in the perioperative period. The included studies were categorized under various settings such as trauma, obstetrics, orthopedics, intensive care unit (ICU), cardiovascular, transplant, and miscellaneous scenarios. TEG showed promising results in trauma surgeries in predicting mortality, hypercoagulability, and bleeding even when it was compared to conventional methods. TEG was also useful in monitoring anticoagulant therapy in orthopedic and obstetric surgeries; however, its role in predicting thrombotic events, hypercoagulability, or complications was questionable. In ICU patients, it showed promising results, especially in the prediction or improvement of sepsis, coagulopathy, thrombotic events, ICU duration, hospital stay, and ventilator duration. TEG parameters effectively predicted hypercoagulation in transplant surgeries. Regarding cardiovascular surgeries, they were effective in the prediction of the need for blood products, coagulopathy, thrombotic events, and monitoring anticoagulation therapy. More randomized clinical trials comparing TEG parameters with standardized tools are needed to produce robust results to standardize its use in different perioperative settings.

The use of an ultrasonic curettage device in orthognathic surgery decreases surgery-related blood loss

Objective

This study aimed to compare the use of a powered instrument (PI) and ultrasonic curettage device (ULCD) with intraoperative blood loss (IOBL), drain volume (DV), calculated blood loss (CBL), and hidden blood loss (HBL) in orthognathic surgery.

Methods

We included 163 patients who underwent bimaxillary surgery in our department. CBL was calculated from the preoperative and postoperative hemoglobin levels using the "hemoglobin balance method." CBL is an indicator of the amount of perioperative blood loss. HBL was calculated by subtracting IOBL and DV from CBL.

Results

The PI group consisted of 61 patients (17 males and 44 females, age: 24.9 ± 9.5 years), and the ULCD group consisted of 102 patients (40 males and 62 females, age: 23.1 ± 7.8 years). In the PI group, the median IOBL, DV, CBL, and HBL were 540.0 (interquartile range [IQR] 380.0-670.0), 113.0 (IQR 77.0-147.0), 1000.0 (IQR 751.4-1248.6), and 285.8 (IQR 151.0-476.4) ml, respectively. In the ULCD group, the median IOBL, DV, CBL, and HBL were 327.5 (IQR 200.0-455.0), 105.5 (IQR 75.3-136.0), 759.5 (IQR 594.9-944.2), and 294.2 (IQR 120.8-456.9) ml, respectively. IOBL and CBL were significantly reduced with ULCD use, but no significant differences were observed in DV and HBL.

Conclusions

This study showed that IOBL decreased with ULCD use, resulting in a decrease in CBL. Conversely, bleeding parameters (DV and HBL), which reflect the amount of bleeding that occurs after wound closure, did not show a decrease with ULCD use.

Gender-specific differences in haemostatic parameters and their influence on blood loss in bimaxillary surgery

Objective

The objectives of this prospective cohort study were to establish gender-related differences in blood loss and haemostatic profiles associated with bimaxillary surgery. In addition, we aimed to identify if any gender differences could be established which might help predict blood loss volume.

Materials and methods

Fifty-four patients (22 males; 32 females) undergoing bimaxillary surgery for skeletal dentofacial deformities were eligible for inclusion. Blood samples were taken 1 day preoperatively and 48 h postoperatively for detailed gender-specific coagulation analysis incorporating global coagulation assays (endogenous thrombin potential) and specific coagulation parameters. Blood loss was measured at two different time points: (1) the end of surgery, visible intraoperative blood loss (IOB) using ‘subtraction method’; and (2) 48 h postoperatively perioperative bleeding volume (CBL-48 h) using ‘haemoglobin-balance method’ and Nadler’s formula. Correlation and regression analyses were performed to identify relevant parameters affecting the amount of blood loss.

Results

Significant differences in IOB and CBL-48 h were observed (p < 0.001). Men had higher IOB versus women, lacking statistical significance (p = 0.056). In contrast, men had significantly higher CLB-48 h (p = 0.019). Reduced CBL-48 h was shown to be most closely associated with the level of Antithrombin-III being decreased in females.

Conclusions

Male gender is associated with higher IOB and CBL-48 compared with females. Gender does not affect IOB regarding haemostatic profile but does correlate strongly with procedure length. Conversely, CBL-48 is closely associated with gender-specific imbalances in the anticoagulant system.

Clinical relevance

Knowledge of gender-related differences will help clinicians establish predictive factors regarding excessive blood loss in orthognathic surgery and identify at-risk patients.

Bone marrow space volume of the mandible influencing intraoperative blood loss in bilateral sagittal split osteotomy: A pilot Study

The aim of this study was to investigate whether the bone marrow space volume of the mandible affects blood loss during bilateral sagittal split osteotomy (BSSO). Sixteen patients who underwent BSSO in our hospital were included in this study. Bone marrow space volume of the mandible was measured by analyzing images from computed tomography. Blood loss during BSSO was measured by weighing gauze, measuring suctioned blood, and adjusting for the volume of irrigation solution used during BSSO. Mean blood loss during BSSO for the 16 patients was 200.5 ml, and patients were divided into: Group I, with less than mean blood loss; and Group II, with greater than mean blood loss. Total bone marrow space volume was significantly greater in Group II (12,450.7 ± 2644.3 mm³) than in Group I (9130.3 ± 3005.8 mm³; P<0.05). A correlation between bone marrow space volume and blood loss during BSSO was suggested, and these results are beneficial for surgeons planning and preparing the orthognathic surgery.

How to approach orthognathic surgery in patients who refuse blood transfusion

Background

Some patients who need surgery refuse a blood transfusion because of their religious beliefs or concerns about blood-borne infections. In recent years, bloodless surgery has been performed successfully in many procedures, and is therefore of increasing interest in orthognathic surgery.

Methods

Ten Jehovah’s Witnesses who visited our bloodless surgery center for orthognathic surgery participated in this study. To maintain hemoglobin (Hb) levels above 10 g/dL before surgery, recombinant erythropoietin (rEPO) was subcutaneously administered and iron supplements were intravenously administered. During surgery, acute normovolemic hemodilution (ANH) and induced hypotensive anesthesia were used. To elevate the Hb levels to >10 g/dL after surgery, a similar method to the preoperative approach was used.

Results

The 10 patients comprised three men and seven women. Their average Hb level at the first visit was 11.1 g/dL. With treatment according to our protocol, the average preoperative Hb level rose to 12.01 g/dL, and the average Hb level on postoperative day 1 was 10.01 g/dL. No patients needed a blood transfusion, and all patients were discharged without any complications.

Conclusions

This study presents a way to manage patients who refuse blood transfusions while undergoing orthognathic surgery. rEPO and iron supplementation were used to maintain Hb levels above 10 g/dL. During surgery, blood loss was minimized by a meticulous procedure and induced hypotensive anesthesia, and intravascular volume was maintained by ANH. Our practical approach to orthognathic surgery for Jehovah’s Witnesses can be applied to the management of all patients who refuse blood transfusions.

Intraoperative Blood Loss in Maxillofacial Trauma Surgery

Background and Objectives

This study is aimed to assess the intraoperative blood loss of patients with maxillofacial bone fracture surgical intervention and to assess their need for blood transfusion.

Materials and Methods

In this retrospective study, intraoperative blood loss of 206 patients with facial bone fractures, who underwent surgery between 2017 and 2018, was retrieved. The patient's demographic information, the amount of blood loss, the type of facial bone fracture, and the patient's requirement for blood products were evaluated.

Results

The average amount of intraoperative blood loss was 77.6 ml, and none of the patients required a blood transfusion during the operation in this group of patients. maxillofacial bone fracture was most common in young males. The leading cause of fractures was motor vehicle accident. There was a reverse correlation between the patient's age and surgical blood loss, but there was no statistically significant relationship between the patient's gender and intraoperative surgical blood loss.

Conclusion

The results of the present study show that preparation for blood transfusion in patients with maxillofacial traumatic bone fracture requiring surgery is uncommon if patients have no systemic disease or specific blood dyscrasias preoperatively.

Is there a hidden blood loss in orthognathic surgery and should it be considered? Results of a prospective cohort study

The aim of this prospective observational study was to investigate the parameter 'hidden blood loss' (HBL) in the context of orthognathic surgery, incorporating undetected bleeding volumes occurring intra- and postoperatively. Orthognathic bleeding volumes were recorded at three different time points. At the end of the operation the visible intraoperative blood loss (VBL) was measured. Additionally, the perioperative blood loss was calculated 24 h and 48 h postoperatively using the 'haemoglobin balance method'. Analysis of the HBL was based on the difference between the visible intraoperative blood loss (VBL) and calculated blood loss (CBL), determined 48 h after surgery. 82 patients (male 33, female 49) were included in this study, of whom 41 underwent bimaxillary surgery and of whom 41 underwent Bilateral Sagittal Split Osteotomy (BSSO). Statistically significant differences with reference to the absolute bleeding volumes were found when comparing the two treatment modalities. In terms of HBL, a bleeding volume of 287.2 ml (±265.9) in the bimaxillary group and 346.9 ml (±271.3) in the BSSO cohort was recorded. This accounted for 32.2% (bimaxillary surgery) and 62.6% (BSSO) of the CBL after 48 h (BIMAX vs. BSSO, p < 0.001). HBL is a valuable adjunct to record within the perioperative management of orthognathic surgery to further improve patient safety and postoperative outcomes.

Analytical parameters and vital signs in patients subjected to dental extraction

Background

Dental consultation may provoke stress to the patient, especially when a dental surgery is going to be performed, stressful situations can cause a reaction in the sympathetic nervous system that could lead to cardiovascular alterations. Blood pressure and cardiac frequency are used often as an indirect measurement and this parameters combined can serve as good indicators of stress. Objective: Analyze the changes in vital signs and analytical parameters induced by a dental extraction.

Material and Methods

24 healthy patients who required a simple dental extraction underwent to a blood test and motorization of their pre- and post-extraction vital signs before, at 2 and 48 hours after the procedure. Data analysis was performed by means of repeated measures one way ANOVA followed by multiple comparisons Bonferroni’s Post-hoc test.

Results

The evaluated patients were 13 women and 11 men with an average age of 35.1. Thirteen patients (54.17% of the sample) were smokers and five were regular drinkers (20.8%). No significant differences were observed in the vital signs with the exception of diastolic blood pressure and cardiac rate that were slightly lower after extraction. Only two analytical parameters showed statistical significant changes. Total bilirubin was significantly higher at 48 hours after extraction and leukocyte count was significantly lower at this time. In any case, the magnitude of the changes observed was very low. The analytical parameters and the vital signs did not show any relevant change.

Conclusions

Eventual alterations found after simple tooth extraction should not be attributed to the procedure.

Key words:Blood pressure, heart rate, monitoring physiologic, oxygen saturation, tooth extraction.

Thromboelastography as a Surrogate Marker of Perisurgical Hemostasis in Gaucher Disease

Thromboelastography (TEG) has long been available for routine monitoring of perisurgical and postpartum hemostasis, especially at point of care. The purpose of this study is to retrospectively compare TEG parameters to concomitant standard clotting test results in an unselected cohort of patients with Gaucher disease to ascertain whether TEG values are specific and sensitive enough to substitute for classic coagulation tests for decision making. This remains a cogent concern because of high incidence of thrombocytopenia in patients with Gaucher disease. Thromboelastography values were compared to concomitant platelet counts, partial thromboplastin time, international normalization ratio, and plasma fibrinogen. Demographic characteristics were collected from patients’ files. There were 22 patients with Gaucher disease (2 children; 12.5%) for whom there were 24 TEG results at the same time as classic coagulation test results and 30% performed platelet function tests. The current study shows linear and/or monotonic relationships between platelet counts and several TEG values that were significant over a range of platelet counts including severe thrombocytopenia. The fibrinogen component, correlating only with the rate of clot lysis, played a lesser role. Based on these preliminary results albeit in a small cohort with only 1 case of hemorrhage, there is putative support for the intention to treat patients with Gaucher disease based on TEG results using the same TEG protocol as for other patients undergoing comparable procedures in our institution.

Factors influencing intraoperative blood loss in orthognathic surgery

This retrospective study aimed to identify factors of importance for intraoperative blood loss relative to total blood volume in patients undergoing orthognathic surgery. The study included 356 patients treated consecutively at a Danish university hospital between 1 January 2010 and 31 December 2012. Inclusion criteria were (1) patient age ≥18 years and (2) patient undergoing a three-piece Le Fort I osteotomy, a bilateral sagittal split osteotomy, or a combination of the two. The patient-specific relative blood loss was calculated as a percentage by dividing the intraoperative blood loss by the estimated preoperative total blood volume, and then correlated with body mass index (BMI), age, sex, operating time, and treatment modality in a multivariate stepwise regression analysis. Operating time (P<0.001), BMI (P<0.001), and treatment modality (P<0.001) had a significant impact on relative blood loss; no significant effect of age or sex was observed. The coefficient of determination of relative blood loss was R(2)=0.34. In conclusion, this study introduces relative blood loss as a patient-specific measure of intraoperative blood loss. Average relative blood loss in this patient sample was 6.5%. Extensive surgery, a prolonged operating time, and reduced BMI significantly increase the intraoperative relative blood loss in patients undergoing orthognathic surgery.

Assessment of hematologic parameters before and after bimaxillary orthognathic surgery

PURPOSE

The purpose of the study was to evaluate changes of hematologic parameters in bimaxillary surgery.

METHODS

Fifty-three patients were prospectively evaluated and divided into groups based on the surgical procedure and sex (predictor variables). Hemoglobin, red blood cells, hematocrit, and platelet were the primary outcome variables, operation time the secondary outcome, and the patients' age and weight the other variables.

TRIAL REGISTRATION

NCT02364765 (U.S. National Institutes of Health, clinicaltrials.gov).

RESULTS

There was statistically significant difference between all hematologic parameters before and after surgery, for both men and women, and for all surgical groups. There was a positive correlation between operative time and the decrease (in %) of the hematologic parameters. Linear regression analysis suggested that the Hb values decrease 0.083 % for every minute increase in the operation time, and 0.066, 0.066, and 0.010 % for RBC, Hct, and platelet count, respectively. There was a negative correlation between weight and all hematologic parameters. Correlations between age and hematologic parameters were not statistically significant. Almost all correlations between age, weight, sex, and the surgery group and the hematologic parameters were considered as very weak. Only one patient was transfused.

CONCLUSIONS

It is suggested that operation time and patient's weight play a bigger role than patient's age and sex in the decrease of hematologic parameters after bimaxillary surgery.

Operative Time, Airway Management, Need for Blood Transfusions, and In-Hospital Stay for Bimaxillary, Intranasal, and Osseous Genioplasty Surgery: Current Clinical Practices

PURPOSE

The purpose of this study was to assess operative time, perioperative airway management, early postoperative cardiopulmonary health, need for blood transfusion, and in-hospital stay associated with simultaneous bimaxillary, intranasal, and osseous genioplasty surgery.

MATERIALS AND METHODS

The authors executed a retrospective cohort study derived from patients treated by 1 surgeon at a single institution from 2009 through 2014. The sample consisted of a consecutive series of patients with symptomatic chronic obstructed nasal breathing and a dentofacial deformity (DFD). All underwent at least a Le Fort I osteotomy, sagittal ramus osteotomies, septoplasty, inferior turbinate reduction, and osseous genioplasty. For each patient, the design of the osteotomies and the fixation techniques were consistent. The outcome variables included need for blood transfusion, operating time, success of nasotracheal intubation, time and place of extubation, early postoperative cardiopulmonary health, length of in-hospital stay, and need for readmission after surgery.

RESULTS

For the 166 patients studied, the average age was 25 years (range, 13 to 65 yr; 87 female patients [52%]). The primary patterns of presenting DFD included long face (43 of 166, 26%), maxillary deficiency (41 of 166, 25%), asymmetric mandibular excess (37 of 166, 22%), short face (28 of 166, 17%), and mandibular deficiency (15 of 166, 9%). Forty-two patients (25%) were confirmed to have symptomatic obstructive sleep apnea. The open wound operating time averaged 2 hours 59 minutes (standard deviation, 32 minutes). Only 3 of the 166 patients (1.8%) received blood transfusions. All patients underwent successful nasotracheal intubation. Ninety-six percent of patients were extubated in the operating room and the remaining 4% were extubated in the recovery room. No patients required reintubation or tracheostomy. One hundred thirty-seven patients (83%) were discharged after a 1- or 2-night in-hospital stay. Twenty-five (15%) required a 3-night stay and 4 (2%) required a 4-night hospital stay to achieve adequate oral intake. None of the patients required readmission.

CONCLUSIONS

This study confirms efficient surgical and anesthesia care for patients undergoing simultaneous bimaxillary orthognathic, intranasal, and osseous genioplasty. Anticipating safe nasotracheal intubation with extubation soon after surgery and a limited need for blood transfusion has proved to be the norm. This study confirmed an average in-hospital stay of 2 nights after complex orthognathic surgery without need for readmission.

Global assays of hemostasis

PURPOSE OF REVIEW

There exists an imbalance between our understanding of the physiology of the blood coagulation process and the translation of this understanding into useful assays for clinical application. As technology advances, the capabilities for merging the two areas have become more attainable. Global assays have advanced our understanding of the dynamics of the blood coagulation process beyond end point assays and are at the forefront of implementation in the clinic.

RECENT FINDINGS

We will review recent advances in the main global assays with a focus on thrombin generation that have potential for clinical utility. These assays include direct (thrombogram, whole blood, purified systems) and indirect empirical measures of thrombin generation (thromboelastography) and mechanism-based computational models that use plasma composition data from individuals to generate thrombin generation profiles.

SUMMARY

Empirical thrombin generation assays (direct and indirect) and computational modeling of thrombin generation have greatly advanced our understanding of the hemostatic balance. Implementation of these types of assays and visualization approaches in the clinic will potentially provide a basis for the development of individualized patient care. Advances in both empirical and computational global assays have made the goal of predicting precrisis changes in an individual's hemostatic state one step closer.

Assessment of Intraoperative Blood Loss during Oral and Maxillofacial Surgical Procedures in a Nigerian Tertiary Health Care Center

Background. Reports on estimated amount of blood loss in maxillofacial surgical procedures will guide clinicians through units of blood required for each procedure. The aim of the study was to assess the amount of blood loss and duration of surgery. Methods. All cases of maxillofacial surgical procedures done under GA in the MFU theatre, from January 2007 to December 2013, were included in the study. Pre- and postoperative haematocrit values, number of units of whole blood requested and used, amount of blood loss, and duration of surgery were recorded. Results. 139 patients were analyzed, of which 75 (54.0%) were males and 64 (46.0%) were females. Fifty-six (40.3%) cases involved soft tissues. Eighty-three cases involved hard tissues. Age range was 2 months to 78 years; mean ± (SD) was 21.3 ± (18.5) years. Isolated unilateral cleft lip had the lowest mean value of estimated blood loss of 10.4 ± 10.8 mLs and also the lowest duration of surgery of 58 (76) minutes. There was no significant relationship between both parameters for cleft lip. Fractures of the mandible had mean blood loss of 352 mLs and duration was 175 min. Conclusion. In this study, there was significant relationship between estimated blood loss and duration of surgery for mandibular and zygomatic complex fractures.

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.