Fluid therapy in the critically ill patient

Fluid therapy products for use in the critically ill patient are described. Various specific clinical syndromes are described in detail, including shock, hypoalbuminemia, heart failure, liver failure, diabetic keto-acidosis and pancreatitis. Pathophysiology and specific therapeutic recommendations are given for these clinical syndromes.     

Monitoring the critically ill patient

Monitoring is the key to a successful critical care endeavor. It is the only way in which we know if we did a good thing and if we did enough of it (or too much). Oftentimes, the decision to treat or not to treat is made difficult by the paucity of information available. The secret is to make an intuitive decision and then monitor the patient to see if it was the right or the wrong decision. Most wrong decisions can be caught and corrected long before the patient has suffered the consequences. Go forth, and monitor!     

Analgesia and sedation in the critically ill

Objective: To summarize the challenges to recognizing pain in critically ill patients, the rationale for treatment even in the absence of signs of pain, and the therapeutic options available in the intensive care environment. Etiology: Pain is one of many stressors challenging the critically ill patient, and may in turn be multifactorial in nature. Common causes include local and systemic inflammation, injuries, diagnostic and therapeutic procedures, immobilization, and thrombosis. Diagnosis: Critically ill animals with pain may not demonstrate overt behavioral or physiologic signs of distress. Therefore, pain must be assumed to be present for animals whose condition puts them at risk. Therapy: Currently available analgesic and sedative drugs and methods of delivery are described. Several useful analgesics and sedatives may be co‐administered as fluid additives to provide continuous therapy. Prognosis: There is growing evidence that the neuroendocrine stress response to severe injury or illness may become sufficiently intense to contribute to morbidity and mortality. Many therapeutic analgesic and sedation options provide good control of pain and stress, and in some circumstances this may improve the outcome of critical illness.     

Hypocalcemia in a critically ill patient

Objective: To present a case of clinical hypocalcemia in a critically ill septic dog. Case summary: A 12‐year old, female spayed English sheepdog presented in septic shock 5 days following hemilaminectomy surgery. Streptococcus canis was cultured from the incision site. Seven days after surgery, muscle tremors were noted and a subsequent low serum ionized calcium level was measured and treated. Intensive monitoring, fluid therapy, and antibiotic treatment were continued because of the sepsis and hypocalcemia, but the dog was euthanized 2 weeks after surgery. New or unique information provided: Low serum ionized calcium levels are a common finding in critically ill human patients, especially in cases of sepsis, pancreatitis, and rhabdomyolysis. In veterinary patients, sepsis or streptococcal infections are not commonly thought of as a contributing factor for hypocalcemia. Potential mechanisms of low serum ionized calcium levels in critically ill patients include intracellular accumulation of calcium ions, altered sensitivity and function of the parathyroid gland, alterations in Vitamin D levels or activity, renal loss of calcium, and severe hypomagnesemia. Pro‐inflammatory cytokines and calcitonin have also been proposed to contribute to low ionized calcium in the critically ill. Many veterinarians rely on total calcium levels instead of serum ionized calcium levels to assess critical patients and may be missing the development of hypocalcemia. Serum ionized calcium levels are recommended over total calcium levels to evaluate critically ill veterinary patients.     

Monitoring the critically ill equine patient.

Measurements of physiologic parameters, such as blood pressure or lactate concentration, are useful to detect occult derangements, such as tissue hypoxia and dysoxia. These tools are also useful in determining the effects of therapy. Monitoring techniques are now widely available for the intensive management of critically ill horses and foals. A number of these have evolved into noninvasive or minimally invasive devices and procedures and provide information that can be used for earlier and more dynamic therapeutic intervention. The goal of increased monitoring is to improve the level of care in the ICU; L ultimately. increased survival of critical patients is the motivation behind enhanced monitoring of physiology, with particular attention being paid to trends or alterations over time. This review highlights practical and informative monitoring tools and techniques and provides normal reference values from the literature.     

Nutrition and the critically ill horse.

A nutritional plan should be incorporated into every treatment plan of the critically ill patient. Weight loss and cachexia are the result of prevalence of catabolic processes over anabolic processes in addition to absolute or relative increased demands and decreased food intake.     

Nutritional requirements of the critically ill patient

The presence or development of malnutrition during critical illness has been unequivocally associated with increased morbidity and mortality in people. Recognition that malnutrition may similarly affect veterinary patients emphasizes the need to properly address the nutritional requirements of hospitalized dogs and cats. Because of a lack in veterinary studies evaluating the nutritional requirements of critically ill small animals, current recommendations for nutritional support of veterinary patients are based largely on sound clinical judgment and the best information available, including data from experimental animal models and human studies. This, however, should not discourage the veterinary practitioner from implementing nutritional support in critically ill patients. Similar to many supportive measures of critically ill patients, nutritional interventions can have a significant impact on patient morbidity and may even improve survival. The first step of nutritional support is to identify patients most likely to benefit from nutritional intervention. Careful assessment of the patient and appraisal of its nutritional needs provide the basis for a nutritional plan, which includes choosing the optimal route of nutritional support, determining the number of calories to provide, and determining the composition of the diet. Ultimately, the success of the nutritional management of critically ill dogs and cats will depend on close monitoring and frequent reassessment.     

Coagulopathy of the critically ill equine patient

Objective – To review the hemostasis literature relevant to development of coagulopathy in the critically ill equine patient.
Data Source – Original scientific and review articles.
Human Data Synthesis – Inflammation plays a critical role in the activation and amplification of clot formation, as well as the impairment of physiologic anticoagulant mechanisms, and fibrinolysis. Earlier identification of coagulopathy in patients at risk and restoration of physiologic hemostasis may result in better outcome. Development of scoring systems based on information other than coagulation markers alone may better identify patients with subclinical coagulopathy.
Veterinary Data Synthesis – Critically ill equine patients commonly at risk for coagulopathy include those with severe gastrointestinal disease, septic foals, and adults subjected to severe systemic inflammatory response syndrome. Publications provide information regarding coagulation markers helpful for identification of hemostatic dysfunction in specific patient populations, as well as information regarding the influence of coagulopathy on outcome. Data regarding clinically relevant information on therapeutic intervention are lacking.
Conclusions – The relationship between inflammation and endotoxemia and development of coagulopathy is better understood in both human patients and the critically ill equine patient. Prospective clinical trials evaluating clinically relevant and financially feasible approaches to treatment are still needed.     

Ventilatory support of the critically ill foal.

Critically ill foals often have respiratory failure and benefit from respiratory support. Conventional mechanical ventilation using modem mechanical ventilators is easily adapted to foals. Establish-ing ventilator settings is a dynamic process aided by constant monitoring of blood gas values, end-tidal carbon dioxide, airway pressures, respiratory volumes, airway resistance, and respiratory compliance. Early weaning is as important as timely initiation of ventilation.     

Anesthesia of the critically ill equine patient.

There is a plethora of information regarding anesthetic management of horses; however, controlled studies of the critically ill equine patient are few.These patients should be managed like any equine anesthetic candidate but much more stringently:I. Preoperative evaluation and appropriate therapy may represent the difference between life and death during the intraoperative and recovery periods. 2. The anesthetic induction and maintenance protocol should be based on the individual situation of the veterinary facility and personnel("comfort zone"). 3. Appropriate monitoring and intraoperative supportive measures are essential. 4. The anesthetic period is a significant perturbation to homeostasis. Even if the horse seems to have done well (ie, as indicated by the cardiopulmonary values), a problem-free anesthetic period does not guarantee a successful recovery, and close monitoring should continue until the horse is ambulatory. 5. Critically ill patients are often in a negative energy balance. Supportive measures to ensure an adequate caloric intake, such as enteral or parenteral nutrition, facilitate healing and return of homeostasis.     

Blood glucose concentrations in critically ill neonatal foals

Reasons for Performing Study: Critical illness is associated with hyperglycemia in humans, and a greater degree and duration of hyperglycemia is associated with nonsurvival. Hypoglycemia is also seen in critically ill humans, and is associated with nonsurvival. This might also be true in the critically ill foal.
Objectives: To investigate the association of blood glucose concentrations with survival, sepsis, and the systemic inflammatory response syndrome (SIRS).
Methods: Blood glucose concentrations at admission (515 foals) and 24 hours (159 foals), 36 hours (95), 48 hours (82), and 60 hours (45) after admission were analyzed. Logistic regression analyses were performed to investigate the association of glucose concentrations with survival, sepsis, a positive blood culture, or SIRS.
Results: 29.1% of foals had blood glucose concentrations within the reference range (76–131 mg/dL) at admission, 36.5% were hyperglycemic, and 34.4% were hypoglycaemic. Foals that did not survive to hospital discharge had lower mean blood glucose concentrations at admission, as well as higher maximum and lower minimum blood glucose concentrations in the 1st 24 hours of hospitalization, and higher blood glucose at 24 and 36 hours. Foals with blood glucose concentrations <2.8 mmol/L (50 mg/dL) or >10 mmol/L (180 mg/dL) at admission were less likely to survive. Hypoglycemia at admission was associated with sepsis, a positive blood culture, and SIRS.
Conclusions and Potential Relevance: Derangements of blood glucose concentration are common in critically ill foals. Controlling blood glucose concentrations may therefore be beneficial in the critically ill neonatal foal, and this warrants further investigation.     

Responsible antimicrobial use in critically ill adult horses

Due to increasing antimicrobial resistance, pressure on veterinarians is mounting to adhere to responsible use of antimicrobial drugs. Antimicrobials are frequently included in the treatment of systemically ill horses due to the strong likelihood of an infection and the innate difficulties in differentiating systemic inflammation secondary to noninfectious from infectious causes. In light of increasing antimicrobial drug resistance and the potential negative impact of antimicrobials on equine patients, every attempt should be made to identify noninfectious disease, choose first-line antimicrobials and discontinue treatment as soon as possible. In most cases, a short duration of antimicrobial therapy ranging from a single dose (e.g. preoperatively) to 24–72 h might be sufficient with long-term treatment being rarely required. This article aims to provide practical guidelines for antimicrobial drug usage in critically ill adult horses by describing ancillary diagnostic aids that can help establishing whether or not an infection is present, discussing commonly encountered pathogens and their typical antimicrobial drug sensitivity patterns, and providing some guidance how to safely shorten the duration of antimicrobial therapy.     

The role of albumin replacement in the critically ill veterinary patient

Objective: To review the human and veterinary literature on the physiological role and effects of therapeutic albumin supplementation. Data sources: Data from human and veterinary literature was reviewed. Human data synthesis: Hypoalbuminemia often occurs in a variety of critical illnesses, and contributes to the development of life‐threatening complications, including pulmonary edema, delayed wound healing, feeding intolerance, hypercoaguability, and multiple organ dysfunction. Serum albumin concentration has been used as a prognostic indicator in cases of chronic hypoalbuminemia. The use of albumin replacement therapy in humans is sometimes controversial, but may be associated with improved morbidity and decreased mortality. Veterinary data synthesis: Unlike human literature, there is a paucity of controlled clinical studies in the literature regarding albumin supplementation in veterinary patients. Rather, the majority of published studies were performed in experimental animals or via retrospective analyses. One recent study evaluated the use of plasma to improve albumin concentration in dogs with hypoalbuminemia. Other older studies investigated wound healing in dogs with experimentally induced hypoalbuminemia. As in human medicine, serum albumin concentration may be helpful as a prognostic indicator in critically ill dogs. Conclusion: Albumin is one of the most important proteins in the body because of its role in maintenance of colloid oncotic pressure, substrate transport, buffering capacity, as a mediator of coagulation and wound healing, and free‐radical scavenging. Albumin replacement in veterinary medicine is difficult, but until prospective clinical trials determine the efficacy of albumin replacement are conducted, a suggested clinical guideline would be to maintain albumin concentration at or above 2.0 g/dl utilizing fresh frozen plasma.     

Acute renal failure as a complication in the critically ill animal

Acute renal failure is associated with a high morbidity and mortality in the intensive care animal. The two most common causes are ischemic/reperfusion injury and insult from nephrotoxins. Damage to the renal cells (e.g., endothelial, tubular, or mesangial cells) and altered hemodynamics result in reduced glomerular blood flow, tubular backleak, tubular obstruction, and/or decreased glomerular permeability. Recognition of ARF during the initiation stage provides the optimal chance for recovery. Adequate circulatory blood volume and systemic blood pressure must be established prior to pharmacologic intervention. Once ARF is in the maintenance phase, metabolic consequences of uremia must be managed.     

Pituitary ACTH and adrenocortical secretion in critically ill dogs

OBJECTIVE: To evaluate pituitary-adrenal function in a population of critically ill dogs by measuring serial plasma concentrations of basal cortisol, ACTH-stimulated cortisol, and endogenous ACTH. DESIGN: Prospective study. ANIMALS: 20 critically ill dogs admitted to an intensive care unit (ICU). PROCEDURE: Basal plasma cortisol, ACTH-stimulated cortisol, and endogenous ACTH concentrations were measured for each dog within 24 hours of admission and daily until death, euthanasia, or discharge from the ICU. Established reference ranges for healthy dogs were used for comparison. Survival prediction index (SPI) scores were calculated for each dog within 24 hours of admission. RESULTS: No significant difference was found between initial concentrations of basal cortisol, ACTH-stimulated cortisol, and endogenous ACTH in 13 dogs that survived and those in 7 dogs that died. High initial basal endogenous ACTH concentrations were correlated with subsequent high values. Low basal ACTH-stimulated cortisol concentrations were predictive of higher subsequent values. All basal and ACTH-stimulated cortisol concentrations were within or above the reference range in the 52 plasma samples collected from the 20 dogs during hospitalization. The SPI scores correlated with outcome (ie, alive or dead), but none of the plasma hormone concentrations correlated with SPI score or outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that none of the critically ill dogs in our study population developed adrenal insufficiency during hospitalization in the ICU.