Estimating Blood Volume in Obese and Morbidly Obese Patients

Lemmens, Harry J. M.; Bernstein, Donald P.; Brodsky, Jay B.

doi:10.1381/096089206777346673

Cited by 194 publications

(159 citation statements)

References 15 publications

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“…Estimated total blood volume was calculated as the patient's weight in kilograms multiplied by 70 ml/kg, which is the mean value for indexed blood volume in normal-weight adults. 15 The incidence and types of major IOCs, POCs, and overall complications were determined for the entire study population and for each of the 8 surgical centers. The incidence of MBL, as well as the average percentage of blood loss, was also determined for the study population and for each surgical center.…”

Section: Data Collection and Analysismentioning

confidence: 99%

Complications and intercenter variability of three-column osteotomies for spinal deformity surgery: a retrospective review of 423 patients

Bianco

Norton

Schwab

et al. 2014

FOC

107

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Object Three-column resection osteotomies (3COs) are commonly performed for sagittal deformity but have high rates of reported complications. Authors of this study aimed to examine the incidence of and intercenter variability in major intraoperative complications (IOCs), major postoperative complications (POCs) up to 6 weeks postsurgery, and overall complications (that is, both IOCs and POCs). They also aimed to investigate the incidence of and intercenter variability in blood loss during 3CO procedures. Methods The incidence of IOCs, POCs, and overall complications associated with 3COs were retrospectively determined for the study population and for each of 8 participating surgical centers. The incidence of major blood loss (MBL) over 4 L and the percentage of total blood volume lost were also determined for the study population and each surgical center. Complication rates and blood loss were compared between patients with one and those with two osteotomies, as well as between patients with one thoracic osteotomy (ThO) and those with one lumbar or sacral osteotomy (LSO). Risk factors for developing complications were determined. Results Retrospective review of prospectively acquired data for 423 consecutive patients who had undergone 3CO at 8 surgical centers was performed. The incidence of major IOCs, POCs, and overall complications was 7%, 39%, and 42%, respectively, for the study population overall. The most common IOC was spinal cord deficit (2.6%) and the most common POC was unplanned return to the operating room (19.4%). Patients with two osteotomies had more POCs (56% vs 38%, p = 0.04) than the patients with one osteotomy. Those with ThO had more IOCs (16% vs 6%, p = 0.03), POCs (58% vs 34%, p < 0.01), and overall complications (67% vs 37%, p < 0.01) than the patients with LSO. There was significant variation in the incidence of IOCs, POCs, and overall complications among the 8 sites (p < 0.01). The incidence of MBL was 24% for the study population, which varied significantly between sites (p < 0.01). Patients with MBL had a higher risk of IOCs, POCs, and overall complications (OR 2.15, 1.76, and 2.01, respectively). The average percentage of total blood volume lost was 55% for the study population, which also varied among sites (p < 0.01). Conclusions Given the complexity of 3COs for spinal deformity, it is important for spine surgeons to understand the risk factors and complication rates associated with these procedures. In this study, the overall incidence of major complications following 3CO procedures was 42%. Risks for developing complications included an older age (> 60 years), two osteotomies, ThO, and MBL.

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Section: Data Collection and Analysismentioning

confidence: 99%

Complications and intercenter variability of three-column osteotomies for spinal deformity surgery: a retrospective review of 423 patients

Bianco

Norton

Schwab

et al. 2014

FOC

107

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“…The blood volume corrected for increasing BMI by Lemmens et al [5] formula is 40% lower than the uncorrected empiric estimate of 70 mL/kg used for non-obese adults. This line of reasoning assumes that plasma volume change is equal to blood volume change.…”

Section: Introductionmentioning

confidence: 75%

“…Normally, factor VIIa and FEIBA replacement is dosed on a per-kilogram basis of actual body weight and there is no mention of exceptions for patients with extreme weight or body mass index (BMI) [3,4]. However, since blood volume and therefore plasma volume do not increase proportionately with the increase in fatty tissue, the dose calculation may better correlate to lean body mass [5,6]. Use of actual body weight in morbidly obese patients may result in overdosing, which can potentially lead to unintended thrombosis in the way of pulmonary embolism or stroke.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, literature was sought to estimate changes in blood volume for the morbidly obese. An article by Lemmens et al, which estimated blood volume based on the patient's BMI, was found and a proportional dose was calculated that was equal to a dose calculated using adjusted body weight with a correction factor of 0.4 [5]. Since the patient had no active bleeding, the decision was made to reduce rFVIIa dosage (Table 1) and follow with standard coagulation surveillance adding rotating thromboelastography (ROTEM).…”

Section: Introductionmentioning

confidence: 99%

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Should the Dose of Recombinant Activated Factor VII Be Adjusted for Morbidly Obese Patients? Balancing Risk of Bleeding With Thrombosis

Lonardo¹,

Lonardo²,

Mone³

et al. 2016

J Hematol

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This case report compared and contrasted calculations for dosing recombinant activated factor VII (rFVIIa) in a morbidly obese patient using estimation of blood volume rather than actual weight or ideal body weight (IBW). A specific case report in a morbidly obese, critically ill patient with new diagnosis of acquired hemophilia A (AHA) was presented. A 64-year-old morbidly obese patient with AHA required emergent surgery for perforated diverticulitis and peritonitis. The patient required bypass treatment with rFVIIa and was initially dosed based on actual weight of 167 kg (body mass index 61). The patient had a history of deep vein thrombosis and new onset of atrial fibrillation. Based on numerous risk factors for both bleeding and the potential for thromboembolism, the rFVIIa dose was adjusted based on calculations using adjusted body weight and blood volume principles, which decreased dosage by 40%, from 15 to 9 mg. With no active bleeding, rFVIIa dosage was adjusted and rotating thromboelastography testing was added to coagulation parameter monitoring. With this change in dosage, hemostasis was maintained and 132 mg of rFVIIa was saved over an 8-day treatment period. There is very limited literature to direct clinicians on rFVIIa dosing in morbidly obese patients. Since obesity is prevalent in all patient populations, clinicians should consider an estimation of blood volume as a means to dose rFVIIa. Adjusting the dose of rFVIIa to account for changes in blood volume is a physiologic target that should help balance the risk of underdosing using IBW and the risk of overdosing using actual body weight.

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“…This difference may be attributed to the lack of a linear relationship between circulating blood volume and weight. 22 Compared with lean body mass, adipose tissue is relatively poorly perfused. Thus, weight-adjusted volume decreases as BMI increases, a finding that may help explain the differences in fluid requirements between our 2 groups.…”

Section: Discussionmentioning

confidence: 99%

Norepinephrine Dosing in Obese and Nonobese Patients With Septic Shock

Radosevich

Patanwala

Erstad

2016

American Journal of Critical Care

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Background Whether or not norepinephrine infusions for support of hemodynamic status in patients with septic shock should be weight based is unknown. This situation is particularly pertinent in patients who are extremely overweight or obese. Objective To compare dosing requirements and effect of norepinephrine on blood pressure in obese and nonobese patients with septic shock. Methods In a retrospective cohort study, data on adult patients with septic shock who received norepinephrine infusion for support of hemodynamic status in a tertiary care, academic medical center were analyzed. Patients were categorized as obese (body mass index ≥ 30) or nonobese (body mass index < 30). The primary outcome was dosing requirements of norepinephrine at 60 minutes after the start of the infusion. The secondary outcome was the log-transformed ratio of mean arterial pressure to norepinephrine. Results The final cohort consisted of 100 obese and 100 nonobese patients. Mean norepinephrine infusion rate at 60 minutes was 0.09 (SD, 0.08) μg/kg per minute in the obese group and 0.13 (SD, 0.14) μg/kg per minute in the nonobese group (P = .006). The non–weight-based dose at 60 minutes was 9 μg/min in obese patients and 8 μg/min in nonobese patients (P = .72). The log transformed mean arterial pressure to norepinephrine ratio at 60 minutes was 2.5 (SD, 0.9) in obese patients and 2.5 (SD, 0.8) in nonobese patients (P = .54) Conclusions Compared with nonobese patients, obese patients with septic shock require lower weight-based doses of norepinephrine and similar total norepinephrine doses.

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Estimating Blood Volume in Obese and Morbidly Obese Patients

Cited by 194 publications

References 15 publications

Complications and intercenter variability of three-column osteotomies for spinal deformity surgery: a retrospective review of 423 patients

Complications and intercenter variability of three-column osteotomies for spinal deformity surgery: a retrospective review of 423 patients

Should the Dose of Recombinant Activated Factor VII Be Adjusted for Morbidly Obese Patients? Balancing Risk of Bleeding With Thrombosis

Norepinephrine Dosing in Obese and Nonobese Patients With Septic Shock

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