Lung protein leakage in feline septic shock

Effectiveness of intravenous fluid resuscitation in hypotensive cats: 82 cases (2012-2019)

OBJECTIVE

To evaluate the effectiveness of intravenous fluid resuscitation in hypotensive cats in an emergency room setting. Secondary objectives were to investigate changes in heart rate (HR) and body temperature (BT) in response to fluid resuscitation, and the association of these changes with patient survival.

DESIGN

Retrospective study.

SETTING

University teaching hospital.

ANIMALS

Eighty-two cats with confirmed hypotension.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Medical records from 2012 to 2019 were searched for cats that had documented systemic arterial hypotension (blood pressure measured using a Doppler ultrasonic flow probe [DBP] < 90 mm Hg) on presentation to the emergency room. Data collected included patient characteristics and DBP, HR, and BT before and after fluid resuscitation, type and volume of fluids administered, and outcome. The median DBP before and after resuscitative fluid therapy in all cats was 65 mm Hg (range, 20-85 mm Hg) and 80 mm Hg (range, 20-128 mm Hg), respectively (P < 0.001). However, only 30 cats (37%) were classified as responders to fluid resuscitation (DBP ≥ 90 mm Hg following bolus therapy). The mean HR and median BT before resuscitative fluid therapy was 159/min and 36.7°C. Following fluid resuscitation, where measured, the mean HR and median BT was 154/min (P = 1.00) and 35.9°C (P = 1.00). No significant differences in HR and BT were identified between responders and non-responders. Cats had a low survival rate of 7%. All survivors (n = 5) were initially bradycardic (HR < 160/min), compared to only 45% of non-survivors (P = 0.4).

CONCLUSIONS

Bolus fluid resuscitation effectively increases blood pressure in hypotensive cats; however, it does not result in normalization of blood pressure, HR, or BT in the majority of cases.

Spontaneous cholecystopleural fistula leading to biliothorax and sepsis in a cat

Case summary

A 13-year-old spayed female domestic shorthair cat presented with pleural effusion and suspected triaditis. Intake vitals and leukocytosis were consistent with a diagnosis of systemic inflammatory response syndrome. Biochemical analysis confirmed a pleural fluid-to-serum bile ratio consistent with a diagnosis of biliothorax. Abdominal ultrasound failed to identify a definitive gall bladder but noted a hypoechoic tubular structure ventral to the liver and contacting the diaphragm. Thoracic ultrasound identified a hyperechoic structure contacting the diaphragm at the same location. Thoracoabdominal CT scan identified a fluid-dense tubular structure extending from ventral to the liver, through a diaphragmatic defect and directly communicating with the pleural space, suspected to be an abnormal gall bladder. The cat was humanely euthanized, and post-mortem analysis confirmed a cholecystopleural fistula arising from the gall bladder with multifocal abscesses, mixed inflammatory hepatic infiltrates and small-cell gastrointestinal lymphoma. Culture of the abscess isolated Parabacteroides merdae, meeting the reported feline criteria for sepsis.

Relevance and novel information

To our knowledge, spontaneous cholecystopleural fistula formation leading to biliothorax and sepsis has not been previously reported in the cat. This case highlights a novel sequela of gall bladder disease in this species, and biliothorax should be a differential diagnosis for pleural effusion in cats with evidence of cholecystitis or triaditis.

Prevalence and risk factors for development of hemorrhagic gastro-intestinal disease in veterinary intensive care units in the United Kingdom

OBJECTIVE

To determine the prevalence of hemorrhagic gastro-intestinal (GI) disease developing in dogs and cats admitted for management of non-GI disease in veterinary intensive care units (ICUs).

DESIGN

Retrospective study of animals presented between October 2012 and July 2013.

SETTING

Three ICUs located in veterinary teaching hospitals in the United Kingdom.

ANIMALS

Dogs (n = 272) and cats (n = 94) were consecutively enrolled from 3 ICUs if they were hospitalized in the unit for at least 24 hours. Cases were excluded if they had hemorrhagic GI disease in the 48-hour period before presentation or in the 24-hour period after admission. Cases were also excluded if they suffered skull fracture, epistaxis, or hemoptysis, if they underwent surgical procedures of the GI or upper respiratory tracts, or if they were presented for management of GI disease.

MEASUREMENTS AND MAIN RESULTS

Hemorrhagic GI disease was observed in dogs at all 3 units, but at different rates (Center 1: 10.3%, Center 2: 4.8%, Center 3: 2.2%). Hemorrhagic GI disease was not observed in cats at any of the participating centers. Construction of a multivariable logistic regression model revealed that serum albumin concentration, administration of prophylactic gastro-protectant drugs, and institution were significantly associated with the development of hemorrhagic GI disease in dogs. Development of hemorrhagic GI disease and placement of a feeding tube were significantly associated with mortality during the period of hospitalization in dogs. Thirty-seven (13.6%) dogs and 12 (12.8%) cats died or were euthanized while hospitalized, with a higher mortality rate (42.1%) in dogs with hemorrhagic GI disease.

CONCLUSIONS

Hemorrhagic GI disease does develop in dogs hospitalized for management of non-GI disease, but this phenomenon was not observed in cats. Development of hemorrhagic GI disease appeared to have a significant impact on survival in veterinary ICUs.

The Flat Cat

Aim:

Detailed information regarding the causes and treatment of acute collapse in the cat can be difficult to locate in a single published source. This two-part review aims to provide a logical approach to the clinical assessment and stabilisation of the critically ill collapsed cat.

Practical relevance:

Cats are particularly challenging when presented as emergency patients, often in the later stages of an illness or with a vague history and non-specific signs. The nuances of the critically ill cat are considered, especially for shock and its management.

Clinical challenges:

Shocked cats do not present in the classic stages typically seen in dogs, and the signs are more subtle. Therefore, the clinician must consider whether physical parameters are appropriate for the state and environment of the patient; for example, a normal heart rate in a shocked cat would be considered inappropriate.

Audience:

This review is directed at any veterinarian working with feline patients, and particularly those dealing with emergencies on a regular basis.

Evidence base:

There is an extensive body of published literature, both original studies and textbook chapters, pertaining to the causes and treatment of collapse in the cat. In this article the authors draw on information from original publications, reviews and their clinical experience to provide practical guidance to assist in the emergency setting.

Cysteinyl-leukotriene receptor antagonism blunts the acute hypotensive response to endotoxin in cats

This study evaluated the effects of a cysteinyl-leukotriene-1 (cys-LT(1)) receptor antagonist, zarfirlukast, during feline endotoxemia. Six adult, sexually intact male cats received either placebo or zarfirlukast (10mg, PO) and endotoxin (2 μg/kg/h q 6h) in a cross-over design. Rectal temperature, heart rate, systolic arterial blood pressure, plasma tumor necrosis factor (TNF) activity, interleukin (IL)-6 concentration and urine cys-LT to creatinine ratio were evaluated. The rectal temperature, plasma TNF activity and IL-6 concentrations were significantly higher and systolic arterial blood pressure and heart rate significantly lower after endotoxin infusion. Cats treated with zafirlukast had a significantly higher blood pressure at 4h (P=0.002) compared to placebo. Urine cys-LT to creatinine ratio was significantly greater in the cats treated with zafirlukast compared to placebo (P=0.02). Zafirlukast administration ameliorated the acute hypotensive response to endotoxin in cats, but failed to significantly alter rectal temperature, heart rate or production of TNF and IL-6.

Regional microvascular function and vascular reactivity in patients with different degrees of multiple organ dysfunction syndrome

The pathophysiology of multiple organ dysfunction syndrome (MODS) is believed to be related to that of microcirculatory dysfunction. We hypothesized that the severity of MODS is determined by measuring regional variables of microvascular function and vascular reactivity in critically ill patients. Therefore, we compared (a) reactive hyperemia response in the forearm using transcutaneous Po2/Pco2 electrodes and laser Doppler velocimetry, (b) microvascular permeability assessed by strain-gauge plethysmography in legs, and (c) variables derived from gastric tonometry in hemodynamically stable patients with moderate (n = 15) and severe (n = 15) MODS. There were no differences in systemic oxygen delivery, consumption, and oxygen extraction ratio between the groups. Mortality was 20% in patients with moderate MODS and 60% in patients with severe MODS (P = 0.025). Patients with a high MODS score had significantly larger arterial lactate concentrations (3.81 +/- 2.7 mmol/L) than patients with moderate MODS (1.66 +/- 0.82 mmol/L; P = 0.006). No significant differences in gastric pHi, gastric regional-to-arterial Pco2 difference, capillary filtration coefficient, isovolumetric venous pressure, and skin reactive hyperemia response were observed between patients with moderate and severe MODS. Once MODS is established, regional variables of microvascular function and vascular reactivity measured in this study do not reflect severity of organ dysfunction.

RAPID ALTERATIONS IN TRANSFERRIN SIALYLATION DURING SEPSIS

The inflammatory process is associated with alterations in iron metabolism. Transferrin, an acute-phase N-glycosylated glycoprotein, plays an important role in iron transport. Human serum transferrin contains two biantennary glycans, each consisting of 0 to 4 molecules of sialic acid (SA); its SA content is heterogeneous with high concentration of tetrasialotransferrin (4SA) and low amounts of disialo-, trisialo-, penta-, and hexasialotransferrin. The hepatic uptake of iron is greater for desialylated transferrin isoforms (disialotransferrin) than for the other forms. We hypothesized that serum levels of carbohydrate-deficient transferrin (CDT, disialotransferrin) may increase rapidly in septic patients. Blood samples were obtained from critically ill patients with (n = 15) and without (n = 14) documented sepsis and compared with healthy volunteers. The different forms of transferrin were studied by capillary zone electrophoresis; SA concentrations were measured by enzymatic colorimetric assay. There was a significant increase in the proportion of CDT in septic compared with nonseptic patients and volunteers (18.3% [1.3-30.5] vs. 0.7% [0.5-0.9]; P < 0.01 and 0.9% [0.5-1.1]; P < 0.05). Conversely, tri- and tetrasialotransferrin levels were lower in septic patients. Total and free SA concentrations were significantly higher in septic patients than in healthy volunteers. In a sheep model of septic shock secondary to peritonitis, serum free SA was already increased after 15 h. Sepsis is associated with decreased SA content on circulating transferrin and with an increase in blood free SA concentrations. In view of these rapid modifications and the long half-life of transferrin, the most likely explanation is degradation of transferrin by neuraminidase. Further studies including measurement of blood neuraminidase concentration and activity are needed to understand the process and exact role of SA decrease in septic patients.

Severe sepsis in cats: 29 cases (1986-1998)

OBJECTIVE

To document the clinical, clinicopathologic, and pathologic findings in cats with severe sepsis, identify abnormalities unique to this species, and identify criteria that could be used antemortem to diagnose the systemic inflammatory response syndrome in cats.

DESIGN

Retrospective study.

ANIMALS

29 cats confirmed to have severe sepsis at necropsy.

PROCEDURE

Pertinent history, physical examination findings, and results of hematologic and biochemical testing were extracted from medical records.

RESULTS

Clinical diagnoses included pyothorax, septic peritonitis, bacteremia secondary to gastrointestinal tract disease, pneumonia, endocarditis, pyelonephritis, osteomyelitis, pyometra, and bite wounds. Physical examination findings included lethargy, pale mucous membranes, poor pulse quality, tachypnea, hypo- or hyperthermia, signs of diffuse pain on abdominal palpation, bradycardia, and icterus. Clinicopathologic abnormalities included anemia, thrombocytopenia, band neutrophilia, hypoalbuminemia, low serum alkaline phosphatase activity, and hyperbilirubinemia. Necropsy findings included multi-organ necrosis or inflammation with intralesional bacteria.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that severe sepsis in cats is characterized by lethargy, pale mucous membranes, signs of diffuse abdominal pain, tachypnea, bradycardia, weak pulses, anemia, hypoalbuminemia, hypothermia, and icterus. Recognition of this combination of clinical findings should facilitate the diagnosis of severe sepsis in cats.

Postoperative management of the emergency surgery small animal patient

Hypovolemia, hypothermia, and hypotension are common postoperative findings that predispose the critically ill patient to secondary complications. This patient population is especially vulnerable to sepsis, hypoxia, and immune dysfunction. Careful monitoring is essential for early recognition of potentially life-threatening physiologic derangements. Early and aggressive intervention may help minimize systemic insult before it progresses to acute respiratory distress syndrome, acute renal failure, disseminated intravascular coagulation, or multiple organ failure.

The 67gallium-transferrin pulmonary leak index in patients at risk for the acute respiratory distress syndrome

OBJECTIVE

To determine the occurrence and clinical importance of increased pulmonary microvascular permeability in patients at risk for acute respiratory distress syndrome (ARDS).

DESIGN

Prospective, cohort study.

SETTING

Medical and surgical intensive care unit (ICU) and department of nuclear medicine of a university hospital.

PATIENTS

Thirteen consecutive patients at risk for ARDS with sepsis (n = 4), multiple trauma (n = 3), hemorrhagic pancreatitis (n = 5), and near-drowning (n = 1), admitted into the ICU. All patients were intubated and mechanically ventilated in the course of the study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The 67gallium-transferrin pulmonary leak index (PLI) (upper limit of normal in patients scheduled for major surgery 14.7 x 10(-3)/min) was measured within 24 hrs of admission. In addition, radiographic, gas exchange, and ventilatory variables allowing calculation of the Lung Injury Score, were obtained on the day of the PLI (day 0) and from days 1 to 7. Patients were followed until discharge or death in the ICU. No patient developed ARDS (Lung Injury Score of >2.5 in the absence of congestive heart failure) and all but four patients survived. The PLI (median [range]) was 18.5 (7.0 to 81.9) x 10(-3)/min and was supranormal in 8 of 13 patients (p < .001 vs. normal). The PLI correlated with the Simplified Acute Physiology Score (SAPS) II (r[s] = .79, p < .01) and was higher in nonsurvivors than in survivors (p < .05), with a tendency for a higher SAPS II in the nonsurvivors. On day 0, the chest radiographic score of alveolar abnormalities was 0 (0 to 4), indicating absence of radiographic abnormalities in most patients. Also, on day 0, the median PaO2/FIO2 ratio was 257 (range 119 to 460). The Lung Injury Score on day 0 was 1.0 (0 to 2.0), which is consistent with mild acute lung injury in all but one patient. In the course of time, the oxygenation ratio was lower and the Lung Injury Score was higher in nonsurvivors than in survivors, particularly for the Lung Injury Score on days 1 and 2. The PLI correlated directly with the Lung Injury Score on days 0 and 1. On day 0, the PLI correlated inversely with the oxygenation ratio. On the last evaluable day of the first ICU week, the PLI correlated directly with the Lung Injury Score and the positive end-expiratory pressure level. The duration of mechanical ventilation tended to be longer in patients with a supranormal PLI.

CONCLUSIONS

In this small population, 61% of patients at risk for ARDS and with only mild respiratory changes exhibited increased microvascular permeability in the lungs at ICU admission. Increased permeability may be an early marker of acute lung injury and its clinical features, and may be associated with a relatively complicated respiratory course during the first week after admission, even in the absence of progression to ARDS. Finally, increased pulmonary microvascular permeability may be associated with severe underlying disease and ultimate mortality in the ICU.

Radionuclide assessment of pulmonary microvascular permeability

The literature has been reviewed to evaluate the technique and clinical value of radionuclide measurements of microvascular permeability and oedema formation in the lungs. Methodology, modelling and interpretation vary widely among studies. Nevertheless, most studies agree on the fact that the measurement of permeability via pulmonary radioactivity measurements of intravenously injected radiolabelled proteins versus that in the blood pool, the so-called pulmonary protein transport rate (PTR), can assist the clinician in discriminating between permeability oedema of the lungs associated with the adult respiratory distress syndrome (ARDS) and oedema caused by an increased filtration pressure, for instance in the course of cardiac disease, i.e. pressure-induced pulmonary oedema. Some of the techniques used to measure PTR are also able to detect subclinical forms of lung microvascular injury not yet complicated by permeability oedema. This may occur after cardiopulmonary bypass and major vascular surgery, for instance. By paralleling the clinical severity and course of the ARDS, the PTR method may also serve as a tool to evaluate new therapies for the syndrome. Taken together, the currently available radionuclide methods, which are applicable at the bedside in the intensive care unit, may provide a gold standard for detecting minor and major forms of acute microvascular lung injury, and for evaluating the severity, course and response to treatment.

Sepsis/septic shock: participation of the microcirculation: an abbreviated review

OBJECTIVE

An overview of the importance of understanding mechanisms occurring in the microcirculation during septic and endotoxic shock. The thesis of the paper is to place emphasis on this important vascular network to ultimately benefit the patient.

DATA SOURCES

Early descriptions of vascular reactions to endotoxin which suggest that the microcirculation is a major site of attack during shock. More recent studies were sought out and examined as to their possible impacts on the microcirculation.

STUDY SELECTION

Early comprehensive studies concerning vascular reactions in the microcirculation during shock were selected. Subsequent studies identified from the mainstream scientific medical literature describe the actions of blood, cells, and the emerging significant role of the vascular endothelium among other factors. A consensus view is identified, pointing to the causes of a malfunctioning microcirculation during shock.

DATA EXTRACTION

Data gathered from reports in the mainstream, well-established basic and clinical literature, from reviews and forum reports, from studies by well-established investigators, and from more recent reports of excellent quality.

DATA SYNTHESIS

The microcirculation undergoes massive alterations during sepsis/septic shock. There are numerous changes, including slowing of capillary blood flow due to depressed perfusion pressure as a result of systemic pressure reduction and local arteriolar constriction. Observations suggest that the microcirculation is shut off early in severe sepsis, allowing the effects of hypoperfusion and attacks by microorganisms to prevail in their destructive capabilities. Widespread capillary dilation may ultimately occur. However, with blood flow diverted through some arteriovenous channels, important areas of capillary exchange are bypassed. Decreased capillary blood flow during shock results from failure to allow normal passage of cellular elements, including erythrocytes and neutrophils. This defect occurs, in part, because of decreased perfusion pressure, decreased deformability of red and white cells, constricted arterioles, circulating obstructive fragments (including hemoglobin), and plugging of microvessels with "sludge." Other factors are adherence of cells to capillary and venular epithelial membranes creating increased resistance to flow, loss of fluid through abnormal transcapillary exchange, differential vascular resistance changes between various beds (e.g., intestinal vs. muscle), and the relative absence of regulatory neurohumoral control of small vessel segments of the circulation. During sepsis/septic shock, endothelial cells are reported to modulate vascular tone, control local blood flow, influence the rate of leakage of fluids and plasma proteins into tissues, modulate the accumulation and extravasation of white cells into tissues, and influence white cell activation. As a result of the predominance of many destructive factors, a subsequent round of tissue damage may occur. Because of prolonged capillary vascular stasis, deficient flow, and factors released from injured cells, the microcirculation becomes a trap for uncontrolled bacterial growth enhanced by sustained hypoxemia, acidosis and toxemia. These events may combine to contribute to the loss of normal cell integrity and death of the host.

CONCLUSIONS

The purpose of this review is to draw the readers' attention to the growing list of adverse factors occurring in the microcirculation during sepsis/septic shock. A further aim is to point to the realization of the complexity of factors which may contribute to the importance of a well-functioning microcirculation.