Desmame da ventilação mecânica / Weaning from mechanical ventilation

Clinical Techniques in Small Animal Practice

Volume 15, Issue 3, August 2000, Pages 157–164

Critical Care

Weaning from mechanical ventilation

• DVM Matthew S. Mellema, 
• DVM, MS, DACVA, DACVECC Steve C. Haskins

• From the Veterinary Medical Teaching Hospital, and Department of Surgery and Radiological Sciences, University of California, Davis, Davis, CA, USA
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• Patients that require positive pressure ventilation to maintain sufficient alveolar ventilation or pulmonary gas exchange may eventually reach a point in the course of their care wherein mechanical ventilation is no longer necessary. This process of transferring the work of breathing from the ventilator back to the patient is referred to as ventilator weaning. The term “ventilator weaning” may be used to refer to all methods by which this transfer of workload may be accomplished. In many patients, particularly those with short-lasting or readily correctable causes of respiratory insufficiency (eg, general anesthesia), the discontinuation of positive pressure ventilation may be easily achieved. Indeed, in patients awakening from general anesthesia, the axiom “awake enough to blink, awake enough to breath” may prove to be a sufficient guideline. However, in those patients requiring long-term mechanical ventilatory support, the process can prove to be both frustrating and exceptionally challenging. It is of crucial importance to identify those patients that may be successfully weaned because of both the financial impact of prolonged intensive care unit hospitalization and the risks imposed on the patient by the process of positive pressure ventilation. To be able to predict which patients may be ready to be weaned from the ventilator requires an understanding of the balance between the work of breathing (ventilatory load) and the ability of the patient's respiratory pump to meet those needs (ventilatory capacity). The management of patients experiencing difficulty during the weaning process requires that the clinician recognize imbalances between ventilatory load and capacity and to correct these imbalances once identified.

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Lesões orais associadas a intubação orotraqueal em cães criticamente enfermos submetidos a ventilação mecânica / Oral lesions associated with orotracheal administered mechanical ventilation in critically ill dogs

Oral Lesions Associated with Orotracheal Administered Mechanical Ventilation in Critically III Dogs

1. Mack Fudge DVM, MPVM¹, 
2. Jamie G. Anderson DVM, MS^2,†, 
3. Janet Aldrich DVM¹,
4. Steve C. Haskins DVM, MS^3,*

Article first published online: 1 JUL 2007

DOI: 10.1111/j.1476-4431.1997.tb00047.x

Issue

Journal of Veterinary Emergency and Critical Care

Volume 7, Issue 2, pages 79–87, July 1997

Additional Information(Show All)

Summary

The incidence and clinical progression of oral lesions in a cohort of critically ill patients administered mechanical ventilation via orotracheal intubation were observed prospectively in the Intensive Care Unit (ICU) of the University of California, Davis Veterinary Medical Teaching Hospital. Oral cavities of these patients were examined within 24 hours of being placed on the ventilator and at least daily thereafter during ventilator therapy. As part of the study protocol, any lesion noted was treated. Twenty-one critically ill canine patients (median age of 7 yrs; range <1 to 19 yrs) were observed from 1 January 1995 through 31 August 1995. Over ninety percent (90.5%) of the observed patients developed oral lesions subsequent to being mechanically ventilated. Erosive and ulcerative mucosal lesions were the most frequently observed (15/43) with the tongue being the most frequently involved oral structure. Most of the observed soft tissue oral lesions appeared secondary to persistently applied pressure from teeth, mouth gags, endotracheal tubes, and other monitoring devices. Efforts taken to prevent persistently applied trauma, such as periodic positional changes of equipment and padding of susceptible structures, apeared effective in preventing oral lesions. There were indications of gastric reflux in 6 patients (28.6%), as evidenced by secretions in the oral cavity with a pH of <6 and containing digested blood. Ulcerative lesions in the subset of patients with gastric reflux seemed to worsen in severity with exposure to the low pH secretions. Over the course of the study, the ICU nursing staff developed an effective protocol for the care of the oral cavity: treating mucosal erosions and ulcers topically8 with a dilute chlorhexidine solution (0.05%), removing oral secretions via suction as needed, and padding persistently traumatized tissues with glycerin moistened gauze. Oral lesions in orotrachealy intubated and mechanically ventilated patients are predictable, preventable, and treatable. Most lesions are pressure induced, associated with monitoring/therapeutic equipment, and appear to be preventable with appropriate nursing protocls. Most observed oral lesions clinically improved with routine, periodic dilute chlorhexidine rinses and relief of applied pressure.

Indicações, manejo e desfecho após ventilação por pressão positiva por períodos prolongados em cães em gatos : 148 casos /Indications, management, and outcome of long-term positive-pressure ventilation in dogs and cats: 148 cases

Journal of the American Veterinary Medical Association

January 1, 2007, Vol. 230, No. 1, Pages 64-75

doi: 10.2460/javma.230.1.64

Indications, management, and outcome of long-term positive-pressure ventilation in dogs and cats: 148 cases (1990–2001)

Kate Hopper, BVSc, MVS, DACVECC; Steve C. Haskins, DVM, DACVA, DACVECC; Philip H. Kass, DVM, PhD, DACVPM; Marlis L. Rezende, DVM, PhD; Janet Aldrich,DVM, DACVECC

Address correspondence to Dr. Hopper.

Objective

To determine outcome of positive-pressure ventilation (PPV) for 24 hours or longer and identify factors associated with successful weaning from PPV and survival to hospital discharge in dogs and cats.

Design
Retrospective case series.

Animals
124 dogs and 24 cats that received PPV for 24 hours or longer.

Procedures
Medical records were reviewed for signalment, primary diagnosis, reason for initiating PPV, measures of oxygenation and ventilation before and during PPV, ventilator settings, complications, duration of PPV, and outcome. Animals were categorized into 1 of 3 groups on the basis of the reason for PPV.

Results
Group 1 patients received PPV for inadequate oxygenation (67 dogs and 6 cats), group 2 for inadequate ventilation (46 dogs and 16 cats), and group 3 for inadequate oxygenation and ventilation (11 dogs and 2 cats). Of the group 1 animals, 36% (26/73) were weaned from PPV and 22% (16/73) survived to hospital discharge. In group 2, 50% (31/62) were weaned from PPV and 39% (24/62) survived to hospital discharge. In group 3, 3 of 13 were weaned from PPV and 1 of 13 survived to hospital discharge. Likelihood of successful weaning and survival to hospital discharge were significantly higher for group 2 animals, and cats had a significantly lower likelihood of successful weaning from PPV, compared with dogs. Median duration of PPV was 48 hours (range, 24 to 356 hours) and was not as-sociated with outcome.

Conclusions and Clinical Relevance

Results suggested that long-term PPV is practical and successful in dogs and cats.

O papel das citocinas pro e anti-inflamatórias na patogênese das doenças neurológicas espontâneas em caninos / The role of pro- and anti-inflammatory cytokines in the pathogenesis of spontaneous canine CNS diseases

Veterinary Immunology and Immunopathology

Volume 147, Issues 1–2, 15 June 2012, Pages 6–24

Review paper

The role of pro- and anti-inflammatory cytokines in the pathogenesis of spontaneous canine CNS diseases

• I. Spitzbarth, 
• W. Baumgärtner, 
• A. Beineke^, 

Abstract

Dogs are comparatively frequently affected by various spontaneously occurring inflammatory and degenerative central nervous system (CNS) conditions, and immunopathological processes are a hallmark of the associated neuropathology. Due to the low regenerative capacity of the CNS a sophisticated understanding of the underlying molecular basis for disease initiation, progression and remission in canine CNS diseases represents a prerequisite for the development of novel therapeutical approaches. In addition, as many spontaneous canine CNS diseases share striking similarities with their human counterpart, knowledge about the immune pathogenesis may in part be translated for a better understanding of certain human diseases. In addition to cytokine-driven differentiation of peripheral leukocytes including different subsets of T cells recent research suggests a pivotal role of these mediators also in phenotype polarization of resident glial cells. Cytokines thus represent the key mediators of the local and systemic immune response in CNS diseases and their orchestration significantly decides on either lesion progression or remission. The aim of the present review is to summarize the growing number of data focusing on the molecular basis of the immune response during spontaneous canine CNS diseases and to detail the effect of cytokines on the immune pathogenesis of selected idiopathic, infectious, and traumatic canine CNS diseases. Steroid-responsive meningitis arteritis (SRMA) represents a unique idiopathic disease of leptomeningeal blood vessels characterized by excessive IgA secretion into the cerebrospinal fluid. Recent reports have given sophisticated insights into the cytokine-driven, immune-mediated pathogenesis of SRMA that is characterized by a biased T helper 2 cell response. Canine distemper associated leukoencephalitis represents an important spontaneously occurring disease that allows investigations on the basic pathogenesis of immune-mediated myelin loss. It is characterized by an early virus-induced up-regulation of pro-inflammatory cytokines with chronic bystander immune-mediated demyelinating processes. Lastly, canine spinal cord injury (SCI) shares many similarities with the human counterpart and most commonly results from intervertebral disk disease. The knowledge of its pathogenesis is largely restricted to experimental studies in rodents, and the impact of immune processes that accompany secondary injury is discussed controversially. Recent investigations on canine SCI highlight the pivotal role of pro-inflammatory cytokine expression that is paralleled by a dominating reaction of microglia/macrophages potentially indicating a polarization of these immune cells into a neurotoxic and harmful phenotype. This report will review the role of cytokines in the immune processes of the mentioned representative canine CNS diseases and highlight the importance of cytokine/cytokine interaction as a useful therapeutic target in canine CNS diseases.

Avaliação dos fatores que afetam a taxa de filtração glomerular e marcadores indiretos da função renal em cães e gatos / Assessments of factors that affect glomerular filtration rate and indirect markers of renal function in dogs and cats

FULL PAPER

Assessments of Factors that Affect Glomerular Filtration Rate and Indirect Markers of Renal Function in Dogs and Cats

Yuichi MIYAGAWA¹⁾, Naoyuki TAKEMURA¹⁾, Hisashi HIROSE²⁾

Journal of Veterinary Medical Science

Vol. 72 (2010) No. 9 September P 1129-1136

Chronic kidney disease is one of the most common disorders in dogs and cats. The plasma urea nitrogen (P-UN) and creatinine (P-Cre) concentrations are not sufficiently sensitive for early diagnosis of renal dysfunction. Although urine and plasma clearance methods allow earlier detection of reductions in the GFR, it is difficult to estimate a mildly reduced GFR from the values obtained by these methods, as they are also affected by physiological factors, such as body weight (BW) and age. The present study is a retrospective survey designed to assess the factors that affect markers of kidney function and to revaluate the clinical utility of the markers, including P-UN, P-Cre and GFR determined by plasma iohexol clearance (PCio) in dogs and cats. The P-UN, P-Cre and PCio values in dogs and the P-Cre and PCio values in cats were significantly correlated with BW (P<0.001). PCio in smaller dogs (≤ 15.0 kg) was significantly and inversely correlated with age. In smaller dogs, increase of P-UN alone might warrant a suspicion of a decreased GFR, but in contrast, P-Cre may be inefficient for detecting renal dysfunction or determining the severity of CKD compared with that in larger dogs (≥ 15.1 kg). P-Cre in larger dogs correlated better with PCio than in smaller dogs, suggesting that P-Cre in larger dogs was a more sensitive marker of reduced GFR.

Efeitos da infusão de dopamina, dobutamina, epinefrina e fenilefrina em doses crescentes in felinos sadios anestesiados / Effects of increasing infusion rates of dopamine, dobutamine, epinephrine, and phenylephrine in healthy anesthetized cats

Abstract

American Journal of Veterinary Research

September 2006, Vol. 67, No. 9, Pages 1491-1499

doi: 10.2460/ajvr.67.9.1491

Effects of increasing infusion rates of dopamine, dobutamine, epinephrine, and phenylephrine in healthy anesthetized cats

Peter J. Pascoe, BVSc; Jan E. Ilkiw, BVSc, PhD; Bruno H. Pypendop, Dr Med Vet, Dr Vet Sci

Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616. (Pascoe, Ilkiw, Pypendop)

Objective

To determine the cardiopulmonary effects of increasing doses of dopamine, dobutamine, epinephrine, and phenylephrine and measure plasma concentrations of norepinephrine, epinephrine, and dopamine in cats anesthetized with isoflurane.

Animals
6 healthy adult cats.

Procedures
Each cat was anesthetized with isoflurane (1.5 X minimum alveolar concentration) on 4 occasions. Cardiopulmonary measurements were obtained after a 30-minute stabilization period; 20 minutes after the start of each infusion dose; and 30, 60, and 90 minutes after the infusion was discontinued. Cats received 5 progressively increasing infusions of epinephrine or phenylephrine (0.125, 0.25, 0.5, 1, and 2 μg/kg/min) or dobutamine or dopamine (2.5, 5, 10, 15, and 20 μg/kg/min). The order of treatment was randomly allocated.

Results
All 4 treatments increased oxygen delivery. Heart rate (HR) increased during administration of all drugs except phenylephrine, and mean arterial pressure increased during administration of all drugs except dobutamine. A progressive metabolic acidosis was detected, but whole-blood lactate concentration only increased during administration of epinephrine and dobutamine. Systemic vascular resistance index increased during administration of phenylephrine, decreased during administration of dobutamine, and remained unchanged during administration of dopamine and epinephrine. A positive inotropic effect was detected with all treatments.

Conclusions and Clinical Relevance

During anesthesia in cats, administration of dopamine, dobutamine, and epinephrine may be useful for increasing cardiac output, with dopamine having the most useful effects. Administration of phenylephrine increased cardiac and systemic vascular resistance indexes with minimal effect on HR and may be useful for increasing mean arterial pressure without increasing HR.

Hemodinâmica renal e efeitos diuréticos da baixa dose de dopamina em gatos anestesiados / Renal hemodynamic and diuretic effects of low-dosage dopamine in anesthetized cats

Renal hemodynamic and diuretic effects of low-dosage dopamine in anesthetized cats

1. James S. Wohl DVM, Diplomate ACVIM, ACVECC¹, 
2. Dean D. Schwartz PhD², 
3. W. Shannon Flournoy DVM, MS¹, 
4. Terrence P. Clark DVM, PhD, Diplomate ACVCP⁴,
5. James C. Wright DVM, PhD, Diplomate ACVPM³

Article first published online: 26 JAN 2007

DOI: 10.1111/j.1476-4431.2006.00209.x

Issue

Journal of Veterinary Emergency and Critical Care

Volume 17, Issue 1, pages 45–52, March 2007

Additional Information(Show All)

Keywords:

• diuresis;
• dopaminergic;
• feline;
• renal protection;
• urine output

Abstract

Objective: To evaluate the effects of low-dosage (3 μg/kg/min) dopamine on urine output, renal blood flow, creatinine clearance, sodium excretion, heart rate, and mean arterial pressure (MAP) in healthy anesthetized cats.

Design: Controlled experimental study.

Setting: University experimental laboratory.

Animals: Twelve random-bred 2–4-year-old cats.

Interventions: Anesthesia, laparotomy for renal artery blood flow measurement, and arterial and venous catheterization.

Measurements: Heart rate (HR), MAP, renal blood flow, urine output, sodium excretion, fractional sodium excretion, and creatinine clearance.

Main results: No significant difference in urine output, sodium excretion, HR, or creatinine clearance occurred in cats receiving low-dosage dopamine. A transient decrease in the mean arterial blood pressure occurred in cats receiving dopamine.

Conclusions: Low-dosage dopamine cannot be expected to induce diuresis in healthy cats. Low-dosage dopamine may cause vasodilation in non-renal vascular beds.

Acidente vascular encefálico hemorrágico e isquêmico em cães / Ischaemic and haemorrhagic stroke in the dog

The Veterinary Journal

Volume 180, Issue 3, June 2009, Pages 290–303

Review

Ischaemic and haemorrhagic stroke in the dog

• Annette Wessmann^a, , , 
• Kate Chandler^b, 
• Laurent Garosi^c

• Abstract

  Cerebrovascular disease results from any pathological process of the blood vessels supplying the brain. Stroke, characterised by its abrupt onset, is the third leading cause of death in humans. This rare condition in dogs is increasingly being recognised with the advent of advanced diagnostic imaging. Magnetic resonance imaging (MRI) is the first choice diagnostic tool for stroke, particularly using diffusion-weighted images and magnetic resonance angiography for ischaemic stroke and gradient echo sequences for haemorrhagic stroke. An underlying cause is not always identified in either humans or dogs. Underlying conditions that may be associated with canine stroke include hypothyroidism, neoplasia, sepsis, hypertension, parasites, vascular malformation and coagulopathy. Treatment is mainly supportive and recovery often occurs within a few weeks. The prognosis is usually good if no underlying disease is found.

  
  

  

  

  

  
  

Acidente vascular encefálico isquêmico espontâneo em cães: semelhanças clínicas e topográficas com humanos / Spontaneous ischaemic stroke in dogs: clinical topographic similarities to humans

Clinical Commentary

Spontaneous ischaemic stroke in dogs: clinical topographic similarities to humans

1. H. Gredal^1,*, 
2. G. C. Skerritt², 
3. P. Gideon³,
4. P. Arlien-Soeborg⁴, 
5. M. Berendt¹

Article first published online: 7 FEB 2013

DOI: 10.1111/ane.12092

© 2013 John Wiley & Sons A/S

Issue

Acta Neurologica Scandinavica

Early View (Online Version of Record published before inclusion in an issue)

Additional Information(Show All)

Keywords:

• animal model;
• canine stroke;
• cerebrovascular accident;
• ischaemic stroke;
• spontaneous stroke

Background

Translation of experimental stroke research into the clinical setting is often unsuccessful. Novel approaches are therefore desirable. As humans, pet dogs suffer from spontaneous ischaemic stroke and may hence offer new ways of studying genuine stroke injury mechanisms.

Aims

The objective of this study was to compare clinical symptoms and infarct topography of naturally occurring ischaemic stroke in pet dogs with human ischaemic stroke.

Methods

Medical records and magnetic resonance imaging (MRI) of 27 dogs with spontaneous ischaemic stroke were retrospectively investigated with respect to clinical symptoms and infarct topography. Symptomatology and MRI characteristics were compared with humans.

Results

Seventy per cent were diagnosed with middle cerebral artery (MCA) occlusions. Motor dysfunction or sensory-motor dysfunction was reported in 78%, including specific signs of contra-lateral motor dysfunction in 11 of 27 (40%). Seizures were reported in 15 of 27 cases (56%).

Conclusions

Spontaneously occurring ischaemic stroke in dogs share characteristics with human ischaemic stroke in terms of clinical symptoms and infarct topography. Investigating pet dogs with spontaneous ischaemic stroke may provide an alternative approach to the research of stroke injury mechanisms as they occur naturally, and should be further investigated.

Colangite/colangiohepatite bacteriana com ou sem colecistite em 4 cães / Bacterial cholangitis/cholangiohepatitis with or without concurrent cholecystitis in four dogs

Bacterial cholangitis/cholangiohepatitis with or without concurrent cholecystitis in four dogs

1. E. J. O’Neill, 
2. M. J. Day, 
3. E. J. Hall, 
4. D. J. Holden, 
5. K. F. Murphy, 
6. F. J. Barr, 
7. G. R. Pearson

Article first published online: 25 MAY 2006

DOI: 10.1111/j.1748-5827.2006.00012.x

Issue

Journal of Small Animal Practice

Volume 47, Issue 6, pages 325–335, June 2006

Additional Information(Show All)

Objectives: To evaluate the clinical, clinical pathology, diagnostic imaging, microbiological and pathological features of cholangitis/cholangiohepatitis in the dog.

Methods: The study design was a retrospective review of cases of bacterial cholangitis/cholangiohepatitis presented to the University of Bristol during the period 1995 to 2000. The diagnosis was made based on hepatic histopathological findings and positive bile culture results.

Results: Four dogs met the inclusion criteria. Common presenting signs included anorexia (n=4), jaundice (n=4), vomiting (n=4) and pyrexia (n=2). All four dogs had a leucocytosis or neutrophilia reported at some time in their history along with serum bilirubin elevation. In addition, serum alkaline phosphatase and alanine transaminase activity was increased in all of the dogs in which it was measured both before and at the time of referral. In general, the diagnostic imaging findings were non-specific. Organisms cultured from bile aspirates were Escherichia coli (n=3), Clostridium species (n=2) and a faecal Streptococcus species (n=1). Two cases resolved with medical treatment alone; two with concurrent cholecystitis required cholecystectomy. Following surgery, both of these cases showed a resolution of clinical signs.

Clinical Significance: This report highlights the fact that bacterial cholangitis/cholangiohepatitis with or without concurrent cholecystitis should be considered as a potential differential in dogs presenting with signs referable to biliary tract disease.