Intralipid microemboli

Clinical effects and adverse effects of intravenous lipid emulsion treatment in dogs and cats with suspected poisoning

This retrospective study aimed to evaluate the effects on the clinical signs of poisoning and adverse effects of intravenous lipid emulsion treatment in 82 animals (dogs and cats) with suspected poisonings over 18 months. Physical examination parameters and state of consciousness were documented every hour after the intravenous administration of a bolus of 2 ml/kg and 0.25 ml/kg/min over 60 minutes of a 20% intravenous lipid emulsion. The modified Glasgow coma scale and laboratory findings (blood gas analysis, triglyceride, lactate) were evaluated initially and three hours after discontinuing intravenous lipid emulsion administration. A statistical evaluation of the occurrence of adverse effects and the development of laboratory values was performed. A decrease in respiratory rate in the second control (8-12 hours) after ILE was observed. Three hours after completing of the intravenous lipid emulsion, triglyceride concentration increased about 10 times (p <0.001). Venous carbon dioxide partial pressure, bicarbonate, base excess, as well as the electrolytes sodium, potassium and ionized calcium decreased significantly (p <0.001). Patients who experienced a worsening of the modified Glasgow coma scale had a higher increase in triglyceride concentrations (p = 0.041) and plasma lactate (p = 0.034) and a larger decrease in bicarbonate concentrations (p = 0.053) compared to others. About 54% (n = 44) of the patients showed adverse effects which could be attributed to the administration of intravenous lipid emulsion and may be associated with a higher triglyceride increase. All of them were completely reversible within 33 hours. Adverse effects associated with intravenous lipid emulsion therapy were observed in half of the patients and were associated with a higher increase in triglycerides.

Intravenous lipid emulsion for the treatment of poisonings in 313 dogs and 100 cats (2016-2020)

Introduction

The aim of this retrospective study was to analyze the effect and potential adverse effects of intravenous lipid emulsion (ILE) in poisoned dogs and cats over a 5 years period.

Methods

Medical records of 313 dogs and 100 cats receiving ILE between 2016-2020 were analyzed for suspected toxicant, clinical signs, ILE dosages and frequency, the effect and adverse effects of ILE, and patient outcome.

Results

Dogs and cats were poisoned with mostly unidentified toxicants (48%), rodenticides (8%), recreational drugs and nuts (7% each) and other toxicants. Clinical signs included neurologic deficits (63%), cardiovascular signs (29%), thermoregulation (21%) or gastrointestinal abnormalities (17%). Treatment with ILE was initiated within a median of 6.0 h (1.0-91.0 h) after poisoning. Dogs and cats received a total amount of median 8.0 mL/kg (1.5-66.6 mL/kg) and 15.8 mL/kg (1.8-69.4 mL/kg) ILE, respectively. A positive effect was observed in 74% of the patients, whereas clinical signs worsened in 4% of the patients after ILE administration. No subjective effect was detected in 22% of the patients. Suspected or possible adverse effects of ILE occurred in 6% of the patients, including neurological signs (temporarily reduced consciousness and ataxia), bradycardia, hyperthermia, vomiting, diarrhea, respiratory distress, worsening of the general behavior, facial swelling, and thrombophlebitis. The overall survival rate was 96%. One dog who potentially experienced adverse events was euthanized.

Conclusion

ILE treatment was successful in most patients but can be associated with adverse effects. Administration of ILE should be carefully selected on an individual basis after weighing the possible benefits against potential adverse effects.

Lipid emulsion for xenobiotic overdose: PRO

Infusion of lipid emulsion for drug overdose arose as a treatment for local anaesthetic systemic toxicity (LAST) initially based on laboratory results in animal models with the subsequent support of favourable case reports. Following successful translation to the clinic, practitioners also incorporated lipid emulsion as a treatment for non-local anaesthetic toxicities but without formal clinical trials. Recent clinical trials demonstrate a benefit of lipid emulsion in antipsychotic, pesticide, metoprolol and tramadol overdoses. Formal trials of lipid emulsion in LAST may never occur, but alternative analytic tools indicate strong support for its efficacy in this indication; for example, lipid emulsion has obviated the need for cardiopulmonary bypass in most cases of LAST. Herein, we describe the pre-clinical support for lipid emulsion, evaluate the most recent clinical studies of lipid emulsion for toxicity, identify a possible dose-based requirement for efficacy and discuss the limitations to uncontrolled studies in the field.

Accidental lipid overdose in a preterm infant: A case report

BACKGROUND

Intravenous lipid emulsions (ILEs) provide essential fatty acids during parenteral nutrition (PN). Serious adverse events including death can occur from overdose. We report an accidental overdose in a preterm infant.

METHOD

On Day 2 of life, a 29-week gestational age (GA) twin was accidentally given 47.5 mL of Intralipid20% (≈3x daily amount) in 50-minutes.

RESULTS

No apparent clinical deterioration occurred, although blood samples were lipaemic. Outcomes at 2 years corrected GA were similar to that of his twin. Service changes were made to infusion packaging and administration to avoid similar errors.

CONCLUSIONS

Medication errors in neonates are unfortunately common. Published articles usually focus on poor outcomes, which can increase the distress for parents of children where errors have occurred. Publishing the full spectrum of outcomes instead allows parents and professionals to be aware of all possibilities and lessons learnt, even if serious harm was avoided.

Fatal accidental lipid overdose with intravenous composite lipid emulsion in a premature newborn: a case report

Background

Tenfold or more overdose of a drug or preparation is a dreadful adverse event in neonatology, often due to an error in programming the infusion pump flow rate. Lipid overdose is exceptional in this context and has never been reported during the administration of a composite intravenous lipid emulsion (ILE).

Case presentation

Twenty-four hours after birth, a 30 weeks’ gestation infant with a birthweight of 930 g inadvertently received 28 ml of a composite ILE over 4 h. The ILE contained 50% medium-chain triglycerides and 50% soybean oil, corresponding to 6 g/kg of lipids (25 mg/kg/min). The patient developed acute respiratory distress with echocardiographic markers of pulmonary hypertension and was treated with inhaled nitric oxide and high-frequency oscillatory ventilation. Serum triglyceride level peaked at 51.4 g/L, 17 h after the lipid overload. Triple-volume exchange transfusion was performed twice, decreasing the triglyceride concentration to < 10 g/L. The infant’s condition remained critical, with persistent bleeding and shock despite supportive treatment and peritoneal dialysis. Death occurred 69 h after the overdose in a context of refractory lactic acidosis.

Conclusions

Massive ILE overdose is life-threatening in the early neonatal period, particularly in premature and hypotrophic infants. This case highlights the vigilance required when ILEs are administered separately from other parenteral intakes. Exchange transfusion should be considered at the first signs of clinical or biological worsening to avoid progression to multiple organ failure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-03064-6.

Parenteral Nutrition and Cardiotoxicity

Parenteral nutrition (PN) is a life-saving nutritional therapy for those situations when patients are unable to receive enteral nutrition. However, despite a multitude of benefits offered by PN, it is associated with a variety of side effects, most notably parenteral nutrition-associated liver disease (PNALD). Adverse effects of PN on other organ systems, such as brain and cardiovascular system, have been poorly studied. There have been several case reports, studies, and a recent animal study highlighting cardiotoxic effects of PN; however, much remains unclear about the underlying mechanisms causing cardiac damage. In this review, we propose a series of potential mechanisms behind PN-associated heart injury, and we provide an overview of therapeutic strategies and recent scientific advances.

Systematic review of clinical adverse events reported after acute intravenous lipid emulsion administration

BACKGROUND

Intravenous lipid emulsions (ILEs) were initially developed to provide parenteral nutrition. In recent years, ILE has emerged as a treatment for poisoning by local anesthetics and various other drugs. The dosing regimen for the clinical toxicology indications differs significantly from those used for parenteral nutrition. The evidence on the efficacy of ILE to reverse acute toxicity of diverse substances consists mainly of case reports and animal experiments. Adverse events to ILE are important to consider when clinicians need to make a risk/benefit analysis for this therapy.

METHODS

Multiple publication databases were searched to identify reports of adverse effects associated with acute ILE administration for either treatment of acute poisoning or parenteral nutrition. Articles were selected based on pre-defined criteria to reflect acute use of ILE. Experimental studies and reports of adverse effects as a complication of long-term therapy exceeding 14 days were excluded.

RESULTS

The search identified 789 full-text articles, of which 114 met the study criteria. 27 were animal studies, and 87 were human studies. The adverse effects associated with acute ILE administration included acute kidney injury, cardiac arrest, ventilation perfusion mismatch, acute lung injury, venous thromboembolism, hypersensitivity, fat embolism, fat overload syndrome, pancreatitis, extracorporeal circulation machine circuit obstruction, allergic reaction, and increased susceptibility to infection.

CONCLUSION

The emerging use of ILE administration in clinical toxicology warrants careful attention to its potential adverse effects. The dosing regimen and context of administration leading to the adverse events documented in this review are not generalizable to all clinical toxicology scenarios. Adverse effects seem to be proportional to the rate of infusion as well as total dose received. Further safety studies in humans and reporting of adverse events associated with ILE administration at the doses advocated in current clinical toxicology literature are needed.

Insulin/glucose infusion successfully resuscitates bupivacaine-induced sudden-onset circulatory collapse in dogs

PURPOSE

In previous studies, insulin reversed the cardiac toxicity gradually induced by a continuous infusion of bupivacaine. In this randomized controlled study, we intended to simulate a more relevant clinical situation by injecting bupivacaine rapidly as a bolus to induce sudden-onset circulatory collapse in dogs. We then evaluated the insulin effect.

METHODS

Bupivacaine (10 mg.kg(-1) iv) was rapidly administered intravenously to 12 dogs. At the onset of circulatory collapse (defined as a mean arterial pressure [MAP] of 30 mmHg), external chest compression was initiated. Insulin (2 U.kg(-1) iv) was given to the insulin-glucose (IG) group (n = 6) and the same volume of 0.9% saline was given to the control (C) group (n = 6). The primary outcome was successful resuscitation defined as both MAP ≥ 60 mmHg and sinus rhythm on an electrocardiogram that lasted ≥ 60 sec. Hemodynamic and blood variables were measured, including cardiac output and electrocardiogram intervals.

RESULTS

All IG dogs were successfully resuscitated within 15 (3) min, whereas none of the control dogs were resuscitated (P = 0.002). After circulatory collapse, the average MAP was higher in group IG than in group C (P = 0.006).

CONCLUSION

Insulin effectively reversed the sudden-onset circulatory collapse in dogs caused by an intravenous bolus injection of bupivacaine.

Safety of high volume lipid emulsion infusion: a first approximation of LD50 in rats

BACKGROUND

Lipid infusion reverses systemic local anesthetic toxicity. The acceptable upper limit for lipid administration is unknown and has direct bearing on clinical management. We hypothesize that high volumes of lipid could have undesirable effects and sought to identify the dose required to kill 50% of the animals (LD(50)) of large volume lipid administration.

METHODS

Intravenous lines and electrocardiogram electrodes were placed in anesthetized, male Sprague-Dawley rats. Twenty percent lipid emulsion (20, 40, 60, or 80 mL/kg) or saline (60 or 80 mL/kg), were administered over 30 mins; lipid dosing was assigned by the Dixon "up-and-down" method. Rats were recovered and observed for 48 hrs then euthanized for histologic analysis of major organs. Three additional rats were administered 60 mL/kg lipid emulsion and euthanized at 1, 4, and 24 hrs to identify progression of organ damage.

RESULTS

The maximum likelihood estimate for LD(50) was 67.72 (SE, 10.69) mL/kg. Triglycerides were elevated immediately after infusion but returned to baseline by 48 hrs when laboratory abnormalities included elevated amylase, aspartate aminotransferase, and serum urea nitrogen for all lipid doses. Histologic diagnosis of myocardium, brain, pancreas, and kidneys was normal at all doses. Microscopic abnormalities in lung and liver were observed at 60 and 80 mL/kg; histopathology in the lung and liver was worse at 1 hr than at 4 and 24 hrs.

CONCLUSIONS

The LD(50) of rapid, high volume lipid infusion is an order of magnitude greater than doses typically used for lipid rescue in humans and supports the safety of lipid infusion at currently recommended doses for toxin-induced cardiac arrest. Lung and liver histopathology was observed at the highest infused volumes.

Stability of total nutrient admixtures with lipid injectable emulsions in glass versus plastic packaging

PURPOSE

The physical stability of two emulsions compounded as part of a total nutrient admixture (TNA) was studied in lipids packaged in either glass or plastic containers.

METHODS

Five weight-based adult TNA formulations that were designed to meet the full nutritional needs of adults with body weights between 40 and 80 kg were studied. Triplicate preparations of each TNA were assessed over 30 hours at room temperature by applying currently proposed United States Pharmacopeia (USP) criteria for mean droplet diameter, large-diameter tail, and globule-size distribution (GSD) for lipid injectable emulsions. In accordance with conditions set forth in USP chapter 729, the higher levels of volume-weighted percent of fat exceeding 5 microm (PFAT(5)) should not exceed 0.05% of the total lipid concentration.

RESULTS

Significant differences were noted among TNA admixtures based on whether the lipid emulsion product was manufactured in glass or plastic. The plastic-contained TNAs failed the proposed USP methods for large-diameter fat globules in all formulations from the outset, and 60% had significant growth in large-diameter fat globules over time. In contrast, glass-contained TNAs were stable throughout and in all cases would have passed proposed USP limits.

CONCLUSION

Certain lipid injectable emulsions packaged in plastic containers have baseline abnormal GSD profiles compared with those packaged in glass containers. When used to compound TNAs, the abnormal profile worsens and produces less stable TNAs than those compounded with lipid injectable emulsions packaged in glass containers.

Randomised trial of effect of delayed intravenous lipid administration on chronic lung disease in preterm neonates

A recent sevenfold increase in the annual incidence of chronic neonatal lung disease (CNLD) on an intensive care unit was attributed to the early administration of intravenous lipid (IVL) in ventilated preterm neonates. When logistic regression was used to eliminate other confounding variables, early delivery of IVL was independently associated with an eight-fold increase in the likelihood of CNLD. Consequently, we designed a prospective study to detect a halving of the incidence of CNLD by delaying IVL administration from 5 days (as is routine practice) to 14 days. Sixty-four parenterally fed preterm neonates weighing < 1,500 g at birth were randomised to receive IVL either on day 5 or day 14. Analysis was by intention to treat, since several infants in the latter group required no parenteral nutrition by day 14. Our results showed that the relative risk (95% confidence interval) of CNLD at 28 postnatal days was 1.15 (0.81-1.62); at 36 weeks postconception, it was 1.08 (0.59-1.99). A study population of > 2,000 would be required to determine whether these relative risks were significantly different from 1.

Low birthweight infants and total parenteral nutrition immediately after birth. II. Randomised study of biochemical tolerance of intravenous glucose, amino acids, and lipid

This randomised study aimed to compare the biochemical tolerance of three parenteral regimens administered during the first 48 hours of life. Twenty nine infants were randomised to either: (a) glucose 10%; (b) glucose 10%/amino acids; (c) glucose 10%/amino acids/lipid. Blood samples for plasma amino acid profiles, cholesterol, and triglyceride concentrations were taken on arrival in the neonatal unit and again between 36 and 48 hours of life. Arterial or capillary blood gas analysis and blood glucose estimates were performed routinely during the first 48 hours of life. There was a sharp decline in plasma amino acid concentrations in the group following (a) compared with the two groups following (b) and (c) regimens. In all groups plasma triglyceride and cholesterol were not significantly different before and after 48 hours of lipid infusion. Peak mean (SE) bilirubin concentrations (203 (12) v 181 (19) v 220 (20) mumol/l) and the need for phototherapy (nine v eight v five infants) were similar for each of the groups. Hypoglycaemia occurred most frequently during the (b) regimen and least commonly in the (c) group. There are potential health gains from giving parenteral nutrition to low birthweight infants immediately after birth, and this study indicates that restriction of nutritional intake immediately after birth in preterm infants may cause significant metabolic disturbance. This can be prevented by starting a regimen of intravenous amino acids and lipid immediately after birth.

The pathogenesis of fat embolism

Fat embolism is a common autopsy finding in patients with or without a history of trauma. There are two basic mechanisms causing fat to embolize. Depot-derived fat embolism arises by disruption of depot fat, usually as a result of trauma, allowing direct entry into the bloodstream. Plasma-derived fat embolism is caused by agglutination of endogenous or infused exogenous fat such as Intralipid, with consequent embolism. Chylomicrons and Intralipid liposomes are known to undergo calcium-dependent agglutination by C-reactive protein (CRP), and this may play a role in vivo in this type of fat embolism.

A method for the early evaluation of the effects of storage and additives on the stability of parenteral fat emulsions

The combination of sedimentation field-flow fractionation (SedFFF) and photon correlation spectroscopy (PCS) is shown to provide a detailed record of the droplet sizes present in fat emulsions commonly used in parenteral nutrition. The technique presented has been used to record size distribution data for a particular emulsion (Liposyn-II), demonstrating its high stability and lot-to-lot uniformity. The technique is also able to demonstrate how additions of small amounts of electrolytes [0.45% (w/v) NaCl, 0.05% (w/v) CaCl2] tend to destabilize the emulsion, suggesting some caution in the use of total parenteral nutrition (TPN) mixtures. In contrast, a 1:1 mixture with human serum caused no sign of instability in the Liposyn-II. Using the emulsion as a carrier for lipophilic drugs necessitates adding solutions of the drug in nonaqueous solvents, such as DMSO (dimethyl sulfoxide). This solvent's destabilizing effect results in a droplet coalescence that becomes severe after 3-5 days following a 10% (v/v) addition, while a 5% (v/v) addition reaches the same level of coalescence in 10 days.

[Intra-macrophage lipid particles collected by bronchoalveolar lavage: incidence and diagnostic value]

This study aimed to determine the incidence and diagnostic value of fat-laden alveolar macrophages obtained by bronchoalveolar lavage (BAL). In 128 patients, including 66 patients admitted for multiple trauma, 158 BAL were carried out. However, 41 BAL from 32 patients were excluded because of poor quality of samples (not enough macrophages, too many ciliated cells, or haemorrhage). All the patients were intubated and mechanically ventilated, having pulmonary infiltrates on the chest film. BAL samples were examined after staining with oil-red-O. They were considered to be positive when more than 5% of alveolar macrophages contained fat droplets. Among them 14 out of 47 patients (30%) without multiple trauma were positive; 7/14 had never been given any intravenous lipid infusion, and 5/14 had aspiration pneumonia (as opposed to 3/32 patients with negative BAL). Further 27 patients out of the 49 (55%) with multiple trauma were positive. Among them 10/49 had clinical evidence of fat embolism, however, only 7/10 had positive samples. All these last ten patients had been given intravenous lipid infusions. The rate of positive alveolar macrophages was correlated neither with the plasma triglyceride concentration, nor the Fracture Index Score, nor the delay between the end of the lipid infusion and the BAL. There was no significant difference in PaO2/FIO2 ratio between the patients with positive and negative BAL. Positive BAL was significantly associated with lipid infusions. The data therefore suggest that the presence of fat-laden alveolar macrophages are associated with various pathological pulmonary conditions, particularly aspiration pneumonia and lipid infusions.(ABSTRACT TRUNCATED AT 250 WORDS)

Priapism in a patient treated with total parenteral nutrition

Venous thrombosis is a common complication of total parenteral nutrition. We report a case of priapism in a 40-year-old man after administration of total parenteral nutrition for chronic idiopathic intestinal pseudo-obstruction. The patient received glucose, amino acids, and 20% fat emulsion; 12 hours after administration, the patient complained of a persistent, painful penile erection lasting 5 hours. Bilateral corpora cavernosa spongiosum shunts achieved immediate and sustained detumescence, but the patient remained impotent. There was no history of penile or pelvic trauma, hemoglobinopathy, coagulopathy, venous thrombosis, or leukemia. The medical literature describes seven other cases of priapism related to total parenteral nutrition. All of the patients received 20% fat emulsion; two patients developed priapism during the weekly infusion of fat emulsion. Among the multiple factors that can favor thrombosis and therefore priapism during total parenteral nutrition, fat infusion appears to be the most important. Three different mechanisms have been postulated: increase in blood coagulability, effects on red blood cells, and fat embolism. In this patient, platelet function was estimated in vivo by the levels of antiheparin platelet factor 4 and beta-thromboglobulin. These two parameters were both elevated before 20% lipid emulsion and were even higher after the 20% fat-emulsion infusion. Therefore, even if a direct thromboplastic effect is possible, 20% fat emulsion increases platelet activity, which was already high in our patient, and thereby favors priapism.

Introduction of intravenous lipid administration on the first day of life in the very low birth weight neonate

OBJECTIVE

To investigate lipid tolerance in sick, ventilator-dependent, very low birth weight infants from the first day of life and the effects of early introduction of intravenously administered lipid (IVL) on glucose homeostasis.

METHOD

Twenty-nine infants in the neonatal intensive care unit with birth weight less than 1500 gm received isocaloric, isonitrogenous parenteral feedings from day 1 with either IVL, 1 gm/kg from day 1 to 3 gm/kg from day 4 (group I; n = 16), or IVL added only from day 8 (group II; n = 13). Possible adverse clinical effects were monitored. Blood metabolites, nonesterified fatty acids, serum triglycerides, and insulin levels were determined daily. Arterial blood gases were measured and changes in partial pressures of oxygen and of carbon dioxide in arterial blood were compared between the two groups.

RESULTS

Early lipid infusion did not appear to have deleterious effects on blood gas tensions or to increase respiratory morbidity. The incidence of other adverse clinical effects that may be associated with IVL was not increased by earlier introduction of lipid. Serum lipid values were comparable to those of preterm infants receiving IVL at a later postnatal age. Blood glucose concentrations were higher in group II (mean, 7.50 (SEM 0.43) mmol/L) than in group I (mean, 6.01 (SEM 0.28) mmol/L; p less than 0.05). There was no evidence of increased gluconeogenesis in infants in group I and no correlation between blood glucose concentrations and serum nonesterified fatty acid concentrations.

CONCLUSION

When given infusion rates not exceeding 0.15 gm/kg/hr, sick, very low birth weight infants can tolerate IVL with stepwise dose increases from the first day of life without an increased incidence of possible adverse effects.

Pulmonary intravascular lipid in neonatal necropsy specimens

The lungs of 482 liveborn infants were examined at necropsy for the presence of intravascular lipid. Forty one patients had received parenteral feeding (including lipid emulsion in 30), and 441 had died before starting feeds or had received enteral feeds alone. Tissue was processed into wax and then stained with Sudan black; intravascular lipid was found in 15 of 30 infants who had received intravenous fat (Intralipid), but in no others. Those patients with positive lipid staining had received significantly more fat during parenteral nutrition than those in whom intravascular lipid was not found but the two groups were otherwise clinically indistinguishable. Using this staining technique intravascular lipid can be shown relatively often, although only in patients who have received intravenous lipid emulsion. The location of fat, predominantly in small pulmonary capillaries, and the absence of lipid emboli in other organs, suggests that lipid coalescence takes place before death and is not a postmortem artefact. The clinical relevance remains uncertain.

Fat macroglobule formation from chylomicrons and non-traumatic fat embolism

Chylomicrons show calcium-dependent agglutination by C-reactive protein (CRP). This has been suggested as a mechanism by which fat embolism may occur in the absence of trauma. It may also play a role in the pathogenesis of acute pancreatitis in patients with types I and V hyperlipidaemia.