Clinical application of a hemoglobin-based oxygen-carrying solution

Lessons Learned From the Battlefield and Applicability to Veterinary Medicine - Part 2: Transfusion Advances

Since the inception of recent conflicts in Afghanistan and Iraq, transfusion practices in human military medicine have advanced considerably. Today, US military physicians recognize the need to replace the functionality of lost blood in traumatic hemorrhagic shock and whole blood is now the trauma resuscitation product of choice on the battlefield. Building on wartime experiences, military medicine is now one of the country's strongest advocates for the principle of hemostatic resuscitation using whole blood or balanced blood components as the primary means of resuscitation as early as possibly following severe trauma. Based on strong evidence to support this practice in human combat casualties and in civilian trauma care, military veterinarians strive to practice similar hemostatic resuscitation for injured Military Working Dogs. To this end, canine whole blood has become increasingly available in forward environments, and non-traditional storage options for canine blood and blood components are being explored for use in canine trauma. Blood products with improved shelf-life and ease of use are not only useful for military applications, but may also enable civilian general and specialty practices to more easily incorporate hemostatic resuscitation approaches to canine trauma care.

Blood Transfusions in Dogs and Cats Receiving Hemodialysis: 230 Cases (June 1997-September 2012)

Background

Multiple factors exist that contribute to anemia in dogs and cats receiving hemodialysis, can necessitate transfusion.

Objectives

To describe blood product usage in dogs and cats with acute and chronic kidney disease that were treated with intermittent hemodialysis to determine risk factors associated with the requirement for blood product transfusion.

Animals

83 cats and 147 dogs undergoing renal replacement therapy at the Animal Medical Center for acute or chronic kidney disease.

Methods

Retrospective medical record review of all dogs and cats receiving renal replacement therapy for kidney disease, from June 1997 through September 2012.

Results

Blood products (whole blood, packed RBCs, or stromal‐free hemoglobin) were administered to 87% of cats and 32% of dogs. The number of dialysis treatments was associated with the requirement for transfusion in cats (adjusted OR 2.21, 95% CI 1.13, 4.32), but not in dogs (adjusted OR 0.98, 95% CI 0.95, 1.03). Administration of a blood product was associated with a higher likelihood of death in dogs (OR 3.198, 95% CI 1.352, 7.565; P = .0098), but not in cats (OR 1.527, 95% CI 0.5404, 4.317, P = .2).

Conclusions and Clinical Importance

Veterinary hospitals with a hemodialysis unit should have reliable and rapid access to safe blood products in order to meet the needs of dogs and cats receiving dialysis.

Ultrasound-guided intracardiac xenotransfusion of canine packed red blood cells and epinephrine to the left ventricle of a severely anemic cat during cardiopulmonary resuscitation

OBJECTIVE

To describe the use of an ultrasound-guided intracardiac xenotransfusion of canine packed red blood cells (pRBC) to the left ventricle of a severely anemic cat during cardiopulmonary resuscitation (CPR).

CASE SUMMARY

An 8-year-old previously healthy neutered female cat was presented with severe weakness after she had disappeared for 1 month. On presentation, the cat was in hypovolemic shock, laterally recumbent, and severely anemic with massive flea infestation. Within minutes of admission, the cat became agonal and suffered cardiopulmonary arrest. CPR was immediately initiated; however, attempts to gain IV access during CPR were unsuccessful. As the cat's blood type was yet unknown, 10 mL of canine pRBC was transfused directly into the left ventricular chamber using ultrasound guidance, as well as 0.02 mg/kg of epinephrine using a similar technique. The cat regained cardiac activity and once the jugular vein was cannulated it received 20 additional mL of canine pRBC intravenously. The packed cell volume and total plasma protein following the intracardiac transfusion were 0.09 L/L [9%] and 30 g/L [3.0 g/dL], respectively. Subsequent blood typing revealed the cat had type B blood. The cat was discharged 3 days post-CPR and was alive and doing well 3 months following discharge.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first reported case of ultrasound-guided intracardiac canine-to-feline xenotransfusion during CPR.

ISFM Consensus Guidelines on the Diagnosis and Management of Feline Chronic Kidney Disease

Practical relevance:

Chronic kidney disease (CKD) is one of the most commonly diagnosed diseases in older cats. In most cats, CKD is also a progressive disease and can be accompanied by a wide range of clinical and clinicopathological changes. These ISFM Consensus Guidelines have been developed by an independent panel of clinicians and academics to provide practical advice on the diagnosis and management of this complex disease.

Clinical challenges:

Although CKD is a common clinical problem in cats, the manifestations of disease vary between individuals. Thus there is a need for careful and repeat evaluation of cats with CKD and adjustment of therapy according to individual needs. In addition to addressing problems arising from CKD and improving quality of life (QoL) for the patient, therapy may also target slowing the underlying progression of disease and hence prolonging life. While maintaining QoL is of paramount importance in our patients, this can be challenging when multiple therapies are indicated. In some cases it is necessary to prioritise therapy, given an understanding of what is likely to most benefit the individual patient.

Evidence base:

In preparing these Guidelines, the Panel has carefully reviewed the existing published literature, and has also graded the quality of evidence for different interventions to help to provide practical recommendations on the therapeutic options for feline CKD. This is a field of veterinary medicine that has benefited from some excellent published clinical research and further research findings will undoubtedly modify the recommendations contained in these Guidelines in the future.

Canine and feline blood transfusions: controversies and recent advances in administration practices

OBJECTIVES

To discuss and review blood transfusion practices in dogs and cats including collection and storage of blood and administration of products. To report new developments, controversial practices, less conventional blood product administration techniques and where applicable, describe the relevance to anaesthetists and anaesthesia.

DATABASES USED

PubMed and Google Scholar using dog, cat, blood transfusion, packed red blood cells and whole blood as keywords.

CONCLUSIONS

Blood transfusions improve oxygen carrying capacity and the clinical signs of anaemia. However there are numerous potential risks and complications possible with transfusions, which may outweigh their benefits. Storage of blood products has improved considerably over time but whilst extended storage times may improve their availability, a phenomenon known as the storage lesion has been identified which affects erythrocyte viability and survival. Leukoreduction involves removing leukocytes and platelets thereby preventing their release of cytokines and bioactive compounds which also contribute to storage lesions and certain transfusion reactions. Newer transfusion techniques are being explored such as cell salvage in surgical patients and subsequent autologous transfusion. Xenotransfusions, using blood and blood products between different species, provide an alternative to conventional blood products.

Haemolytic anaemia and acute pancreatitis associated with zinc toxicosis in a dog

We describe a case of zinc toxicity in a 14-month-old, female, neutered, Cavalier King Charles spaniel with a 48-hour history of haematochezia, icterus and collapse. Regenerative anaemia with a packed-cell volume of 7 per cent was seen. Prior to referral, radiography had revealed a gastric, metallic foreign body which was removed at exploratory laparotomy. On presentation, the dog was comatose, hypothermic and bradycardic - resuscitation was performed successfully, but the dog then displayed marked abdominal pain. The dog died 12 hours after presentation. At postmortem examination, the animal showed severe icterus. Both kidneys were diffusely dark red; the pancreas was diffusely pale and nodular. Histopathological examination revealed evidence of intravascular haemolysis with blood vessel lumens containing haemoglobin. The renal tubules also contained large amounts of intraluminal haemoglobin with haemoglobin crystals scattered throughout the cortex and medulla. The pancreas exhibited multifocal coagulative necrosis, surrounded by a neutrophil-dominated inflammatory infiltrate. Zinc levels were markedly increased above the normal reference range in both liver and kidney. This report describes the clinical and pathological findings of a case of acute zinc toxicity in a dog following ingestion of a metallic object which resulted in marked haemolytic anaemia and acute pancreatitis.

Anemia of renal disease: what it is, what to do and what's new

PATIENT GROUP

It is estimated that 15-30% of geriatric cats will develop chronic kidney disease (CKD), and that 30-65% of these cats will develop anemia as their renal disease worsens. Anemia of renal disease is multifactorial in its pathogenesis, but the main cause is reduced production of erythropoietin, a renal hormone that controls the bone marrow's production of red blood cells, as kidney disease progresses.

PRACTICAL RELEVANCE

It is important to recognize the presence of anemia of renal disease so that adequate treatment may be instituted to improve quality of life and metabolic function. Erythrocyte-stimulating agents (ESAs), such as epoetin alfa, epoetin beta and darbepoetin alfa, have been developed to counteract the effects of decreased erythropoietin production by the kidneys. These treatments, which are the focus of this review, have 83% similarity in amino acid sequence to the feline hormone. On average, the target packed cell volume (>25%) is reached within 3-4 weeks of ESA therapy.

CLINICAL CHALLENGES

The use of ESAs has been associated with a number of complications, such as iron deficiency, hypertension, arthralgia, fever, seizures, polycythemia and pure red cell aplasia (PRCA). Darbepoetin has a prolonged half-life compared with epoetin and thus can be given only once a week, instead of three times a week. The incidence of PRCA appears to be decreased with darbepoetin use when compared with epoetin use in cats.

EVIDENCE BASE

There is limited published evidence to date to underpin the use of ESAs in cats. This review draws on the relevant publications that currently exist, and the authors' personal experience of using these therapies for over 5 years.

Paraneoplastic syndrome in haemophagocytic histiocytic sarcoma in a dog

A case of metastatic splenic haemophagocytic histiocytic sarcoma (HHS) in a 6-year-old neutered male flat-coated retriever is described. The main clinical findings were hypoalbuminaemia and regenerative anaemia. The diagnosis was based on histological features and expression of CD11d by the neoplastic cells. Tumour cells were shown to produce interleukin (IL)-6, to phagocytose erythrocytes and to take up albumin, as demonstrated by immunohistochemistry and ultrastructural examination. Quantitative polymerase chain reaction identified increased IL-6 gene expression in affected organs. These findings suggest that neoplastic cells are responsible for the clinical features of HHS, by removing erythrocytes and albumin from the blood and releasing cytokines, such as IL-6.

A prospective, randomized comparison of Oxyglobin (HB-200) and packed red blood cell transfusion for canine babesiosis

OBJECTIVE

To establish the efficacy of Oxyglobin (HB-200) in canine babesiosis and compare it to standard therapy, packed red blood cell transfusion (pRBCT) with respect to improvements in specific parameters of blood gas, acid-base, blood pressure, and subjective evaluations.

DESIGN

Prospective, randomized, clinical trial.

SETTING

Onderstepoort Veterinary Academic Hospital.

ANIMALS

Twelve dogs (8-25 kg) naturally infected with Babesia rossi and a hematocrit of 0.1-0.2 L/L (10-20%).

INTERVENTIONS

Treatment groups were randomized to receive either 20 mL/kg of Oxyglobin or pRBCT over 4 hours via a central venous catheter. Transfusions were followed by lactated Ringer's solution infusion. Rectal temperature, femoral arterial and mixed venous blood sampling, oscillometric blood pressure, and subjective assessment of patient status (habitus), and appetite were performed at time points 0, 1, 4, 8, 24, 48, and 72 hours.

MAIN RESULTS

Dogs presented with a hypoalbuminemic alkalosis; hyperchloremic, dilutional acidosis; normotensive tachycardia; pyrexia; depression; and anorexia. Both treatments produced similar results, with the exception of significant differences in pH (4 h); PCO(2) (4 h); hemoglobin (8 h, 24 h); mean arterial pressure (48 h); albumin (4 h, 8 h); habitus (8 h, 48 h); and appetite (24 h). Arterial O(2) content was higher for pRBCT than Oxyglobin at 72 hours, but central venous PO(2) did not differ between groups or over time and was consistently subnormal.

CONCLUSIONS

Oxyglobin provides similar overall improvements to pRBCT in dogs with anemia from babesiosis, with respect to blood gas, acid-base and blood pressure, although patients receiving packed cells tended to have more rapid normalization of habitus and appetite.

Broadband diffuse optical spectroscopy assessment of hemorrhage- and hemoglobin-based blood substitute resuscitation

Hemoglobin-based oxygen carriers (HBOCs) are solutions of cell-free hemoglobin (Hb) that have been developed for replacement or augmentation of blood transfusion. It is important to monitor in vivo tissue hemoglobin content, total tissue hemoglobin [THb], oxy- and deoxy-hemoglobin concentrations ([OHb], [RHb]), and tissue oxygen saturation (S(t)O(2)=[OHb][THb]x100%) to evaluate effectiveness of HBOC transfusion. We designed and constructed a broadband diffuse optical spectroscopy (DOS) prototype system to measure bulk tissue absorption and scattering spectra between 650 and 1000 nm capable of accurately determining these tissue hemoglobin component concentrations in vivo. Our purpose was to assess the feasibility of using DOS to optically monitor tissue [OHb], [RHb], S(t)O(2), and total tissue hemoglobin concentration ([THb]=[OHb]+[RHb]) during HBOC infusion using a rabbit hypovolemic shock model. The DOS prototype probe was placed on the shaved inner thigh muscle of the hind leg to assess concentrations of [OHb], [RHb], [THb], as well as S(t)O(2). Hemorrhagic shock was induced in intubated New Zealand white rabbits (N=6) by withdrawing blood via a femoral arterial line to 20% blood loss (10-15 cckg). Hemoglobin glutamer-200 (Hb-200) 1:1 volume resuscitation was administered following the hemorrhage. These values were compared against traditional invasive measurements, serum hemoglobin concentration (sHGB), systemic blood pressure, heart rate, and blood gases. DOS revealed increases of [THb], [OHb], and tissue hemoglobin oxygen saturation after Hb-200 infusion, while blood total hemoglobin values continued did not increase; we speculate, due to hyperosmolality induced hemodilution. DOS enables noninvasive in vivo monitoring of tissue hemoglobin and oxygenation parameters during shock and volume expansion with HBOC and potentially enables the assessment of efficacy of resuscitation efforts using artificial blood substitutes.

Tissue engineering using autologous microcirculatory beds as vascularized bioscaffolds

Classic tissue engineering paradigms are limited by the incorporation of a functional vasculature and a reliable means for reimplantation into the host circulation. We have developed a novel approach to overcome these obstacles using autologous explanted microcirculatory beds (EMBs) as bioscaffolds for engineering complex three-dimensional constructs. In this study, EMBs consisting of an afferent artery, capillary beds, efferent vein, and surrounding parenchymal tissue are explanted and maintained for 24 h ex vivo in a bioreactor that preserves EMB viability and function. Given the rapidly advancing field of stem cell biology, EMBs were subsequently seeded with three distinct stem cell populations, multipotent adult progenitor cells (MAPCs), and bone marrow and adipose tissue-derived mesenchymal stem cells (MSCs). We demonstrate MAPCs, as well as MSCs, are able to egress from the microcirculation into the parenchymal space, forming proliferative clusters. Likewise, human adipose tissue-derived MSCs were also found to egress from the vasculature and seed into the EMBs, suggesting feasibility of this technology for clinical applications. We further demonstrate that MSCs can be transfected to express a luciferase protein and continue to remain viable and maintain luciferase expression in vivo. By using the vascular network of EMBs, EMBs can be perfused ex vivo and seeded with stem cells, which can potentially be directed to differentiate into neo-organs or transfected to replace failing organs and deficient proteins.

Clinical use of a haemoglobin-based oxygen carrying solution (Oxyglobin) in 48 cats (2002-2006)

The objective of this retrospective study was the evaluation of the administration of a haemoglobin (Hb)-based oxygen carrying solution (Oxyglobin) to cats over a time period of 4 years. Indication, infusion volume/24h, number of Oxyglobin infusions/cat, Hb concentration pre- and post-infusion, adverse events, and patient outcome were evaluated. Forty-eight anaemic cats received 65 Oxyglobin infusions. Prior to administration of Oxyglobin, Hb concentration ranged from 2 to 7.8 g/dl (median 4.9 g/dl), the volume of Oxyglobin administered was 4.4-25 ml/kg/24h (median 9.8 ml/kg/24h). An increase of Hb was noted after 41 of 49 infusion events. Severe side effects were noted in seven cats with cardiac disease, which developed pulmonary oedema (five), pleural effusion (three), and respiratory distress (one). They received 6.7-19.8 ml/kg/24h (median 12.3 ml/kg/24h) of Oxyglobin. Four of these seven cats received whole blood transfusions on the same day; five cats died and one was euthanased. Overall 24-h survival rate was 77%. Administration of Oxyglobin efficiently increased the Hb concentration. However, in cats suffering from cardiac disease, there is a high risk of life-threatening circulatory overload at the doses used in this study.