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1.
Objective: To review the current recommendations and guidelines for mechanical ventilation in humans and in animals with acute respiratory distress syndrome.
Human data synthesis: Acute respiratory distress syndrome (ARDS) in humans in defined as an acute onset of bilateral, diffuse infiltrates on thoracic radiographs that are not the result of heart disease and a significant oxygenation impairment. These patients require mechanical ventilation. Research has shown that further pulmonary damage can occur as a result of mechanical ventilation. Various alveolar recruitment maneuvers and a low tidal volume with increased positive end expiratory pressure (PEEP) have been associated with an increased survival.
Veterinary dat synthesis: Two veterinary reports have characterized ARDS in dogs using human criteria. There are no prospective veterinary studies using recruitment that ventilator-induced lung injury (VILI) occurs in dogs, sheep, and rats.
Conclusion: Recruitment maneuvers in conjunction with low tidal volumes and PEEP keep the alveoli open for gas exchange and decrease VILI. Prospective veterinary research in needed to determine if these maneuvers and recommendation can be applied to veterinary patients.  相似文献   

2.
Over the past several decades, recognition of acute respiratory failure as the cause of death in patients suffering from various clinical conditions has prompted aggressiv investigation into the area of respiratory physiology and supportive respiratory care. With the evolution of emergency medicine and critical care services in both human and veterinary medicine, many patients previously considered unsalvageable due to the severity of their underlying disease are now being resuscitated and successfully supported, creating a new population of critically ill patients. Where only a decade ago these patients would have succumbed to their underlying disease, they now survive long enough to manifest the complications of shock and tissue injury in the form of acute respiratory failure. Investigation into the pathophysiology and treatment of this acute respiratory distress syndrom (ARDS) has facilitated increased clinical application of respiratory theerapy and machanical ventilation.1 The purpose of this paper is to provide a basic review of respiratory mechanics and the pathophysiology of hypoxemia as they relate to airway pressure therapy in veterinary patients and to review the use of airway pressure therapy in veterinary patients This paper is divided into two parts; part I reviews respiratory mechanics and hypoxemia as they apply to respiratory therapy, while part II deals specifically with airway pressure therapy andits use in clinical cases.  相似文献   

3.
The cardiopulmonary effects of 0, 5, 10, and 15 cm of H2O positive end-expiratory pressures (PEEP) were determined in anesthetized, spontaneously breathing horses, using a 4 by 4 Latin-square design with one repetition. Cardiac output, alveolar-arterial oxygen tension difference, alveolar ventilation, dead space/tidal volume ratio, and carbon dioxide elimination were not significantly altered by the procedure. As PEEP was increased, alveolar and arterial oxygen tensions, respiratory exchange ratio, and pH decreased, whereas arterial carbon dioxide tension and oxygen consumption increased. These results indicate PEEP is contraindicated in laterally recumbent spontaneously ventilating anesthetized horses breathing air, because it causes alveolar hypoventilation and does not improve pulmonary gas exchange.  相似文献   

4.
The use of arterial blood gas analysis, pulse oximetry, and capnography has become commonplace in the assessment of veterinary patients. Blood gas analysis allows for the qualitative and quantitative assessment of both metabolic and respiratory acid-base problems, including the interrelationships between ventilation, oxygenation, and metabolic conditions. Blood gas analysis is a useful adjunct to clinical patient assessment and other diagnostics in determining appropriate therapy for specific and complex conditions. Both pulse oximetry and capnography are useful monitoring tools. However, they have technical limitations and cannot comprehensively evaluate patient oxygenation and ventilation. Pulse oximetry and capnography are not replacements for arterial blood gas analysis, but rather serve as adjunctive monitoring tools.  相似文献   

5.
Strategies for mechanical ventilation   总被引：5，自引：0，他引：5  
With the advancement of veterinary critical care medicine, an increasing number of veterinary patients are being supported with positive-pressure ventilation. Animals with potentially reversible ventilatory failure (PaCO2 > 60 mmHg) caused by neuromuscular disease or pulmonary parenchymal disease or with pulmonary parenchymal disease causing hypoxemia (PaO2 < 60) despite supplemental oxygen are candidates for ventilatory support. The equation of motion for the respiratory system is defined and is used to describe the potential interactions between the patient and the ventilator. Commonly used modes of ventilation are described in terms of control and phase variables. The intent of this report is to aid clinicians in choosing an optimal ventilatory strategy for each patient that will best achieve the desired physiologic goals with minimal detrimental side effects.  相似文献   

6.
A radiographic technique was used to identify and characterize segmental diaphragmatic movement in anesthetized ponies breathing spontaneously and with controlled ventilation with and without muscle relaxant-induced paralysis. Paralyzed mechanically ventilated ponies were also studied at varying peak inspiratory pressures. Controlled ventilation induced a change in pattern of diaphragmatic displacement which was accentuated by paralysis and increased inspiratory pressure. In conclusion, these results indicate that uneven distribution of inspired gases is not corrected by mechanical ventilation. Furthermore, increased tidal volume during mechanical ventilation is largely wasted because this increased volume is distributed principally to the poorly perfused nondependent lung. Thus, while mechanical ventilation can alleviate hypoventilation, i.e., will decrease PaCO2, it will be of limited value in relieving arterial hypoxemia due to venous admixture in anesthetized patients.  相似文献   

7.
Dogs with lower airway pathology that present in respiratory distress often receive oxygen therapy as the first line of treatment regardless of the underlying cause. Conventional “low-flow” systems deliver oxygen with a maximum flow rate of 15 L/minute. Traditionally, when an animal’s respiratory status does not improve with conventional oxygen therapy and treatments for underlying disease, options might be limited to either intubation and mechanical ventilation or humane euthanasia. High-flow oxygen therapy (HFOT) has been gaining popularity in veterinary medicine as an alternative route of oxygen supplementation for animals that require support beyond conventional therapy. High-flow oxygen therapy can supply a mixture of air and oxygen via a heated and humidified circuit. It is user friendly and can be used in an environment in which mechanical ventilation is unavailable.This review article is written for emergency doctors and general practitioners who lack access to mechanical ventilation. This article briefly reviews pertinent respiratory physiology, traditional oxygen supplementation techniques, the physiology of HFOT, and the limited evidence available in veterinary medicine regarding the use of HFOT, its applications, and limitations. Guidelines for the use of HFOT are suggested and HFOT is compared to conventional therapy.  相似文献   

8.
A foal born 3 weeks prematurely was treated for respiratory distress, using a combination of oxygen therapy and mechanical ventilatory assistance. Clinical response and arterial blood gas tensions were monitored regularly. Continuous positive-airway pressure and intermittent positive-pressure ventilation administered via a nasotracheal tube were effective in improving arterial oxygenation and ventilatory function.  相似文献   

9.
As the specialties of emergency medicine and critical care have grown and evolved in both human and veterinary medicine, so has the need for more advanced care of patients with primary lung disease. Treatment of acute respiratory failure has been the focus of several articles in the human medical literature of the past few years.1,8 This paper deals with airway pressure therapy and its application in cases of acute respiratory failure in veterinary medicine. The reader is referred to part I of this paper for a reveiw of respiratory mechanics and hypoxemia as they apply to respiratory therapy.  相似文献   

10.
REASONS FOR PERFORMING STUDY: Guidelines for administration of oxygen to standing horses are unavailable because previous investigations of the efficacy of oxygen administration to increase arterial oxygenation in standing horses have produced equivocal results. OBJECTIVE: To determine the effect of nasal oxygen supplementation on inspired and arterial blood gas tensions in control horses and those with moderate to severe recurrent airway obstruction (RAO). METHODS: Normal horses (n = 6) and horses during an attack of RAO induced by stabling (n = 6) were studied. Oxygen was administered through either one or 2 cannulae, passed via the nares into the nasopharynx to the level of the medial canthus of each eye. Intratracheal inspired oxygen and carbon dioxide concentration and arterial blood gas tensions were measured at baseline and during delivery of 5, 10, 15, 20 and 30 l/min oxygen. RESULTS: Nasal cannulae and all but the highest oxygen flow rates were well tolerated. Fractional inspired oxygen concentration (F(I)O2) increased with flow but was significantly lower at all flow rates in horses with RAO compared with controls. Arterial oxygen tension (PaO2) was significantly increased (P < 0.001) by all flow rates, but was always lower in RAO-affected animals. At 30 l/min, PaO2 increased to 319 +/- 31 mmHg in control horses and 264 +/- 69 mmHg in horses with RAO. Additionally, a large arterial to end-tidal gradient for CO2 in RAO-affected horses was observed, indicating increased alveolar deadspace ventilation in these animals. CONCLUSIONS: The use of nasal cannulae to deliver oxygen effectively increases both F(I)O2 and PaO2 in horses with moderate to severe RAO. Oxygen flow rates up to 20 l/min are well tolerated, but flow rates of 30 l/min produce occasional coughing or gagging. POTENTIAL RELEVANCE: Oxygen therapy delivered by means of an intranasal cannula is a highly effective means of increasing arterial oxygen tension in horses with respiratory disease. Generally, flows of 10-20 l/min should be effective. If higher flows (20-30 l/min) are necessary, they should be delivered by means of 2 cannulae.  相似文献   

11.
OBJECTIVE: To evaluate the effect of positive end-expiratory pressure (PEEP) on oxygen delivery (DO(2)) with 1-lung ventilation during thoracoscopy in normal anesthetized dogs. STUDY DESIGN: Prospective, controlled experimental study. ANIMALS: Eight, adult, intact Walker Hound dogs weighing 25.6-29.2 kg. METHODS: Anesthetized dogs had 1-lung ventilation during an open-chest condition. A Swan-Ganz catheter was used to measure pulmonary hemodynamic variables and to obtain mixed venous blood samples for blood gas analysis. A dorsal pedal catheter was used for measurement of systemic arterial pressure and to obtain arterial blood samples for blood gas analysis. Oxygen delivery was calculated and used to assess the effect of 0, 2.5, and 5 cm H(2)O PEEP during 1-lung ventilation on cardiopulmonary function. Each dog was its own control at 0 cm H(2)O PEEP. A randomized block ANOVA for repeated measures was used to evaluate the effect of the treatment on hemodynamic and pulmonary variables. RESULTS: Use of 5 cm H(2)O PEEP induced a significant augmentation in the arterial partial pressure of oxygen (PaO(2)). Shunt fraction (Q(s)/Q(t)), physiologic dead space (V(D)/V(T)), and the alveolar-arterial oxygen difference (P(A-a)O(2)) decreased significantly after 5 cm H(2)O PEEP, compared with 1-lung ventilation without PEEP. Use of 2.5 cm H(2)O PEEP had no significant effect on cardiopulmonary variables. Use of PEEP had no significant effect on arterial oxygen saturation (SaO(2)), DO(2), and hemodynamic variables in normal dogs. CONCLUSIONS: PEEP had no effect on DO(2) in normal dogs undergoing open-chest 1-lung ventilation because it had no adverse effect on hemodynamic variables. CLINICAL RELEVANCE: PEEP in normal dogs during open-chest 1-lung ventilation for thoracoscopy is not detrimental to cardiac output and can be recommended in clinical patients.  相似文献   

12.
White rhinoceroses (Ceratotherium simum) anesthetized with etorphine combinations develop severe pathophysiologic changes, including hypoventilation, hypoxemia and metabolic acidosis. The aim of this study was to evaluate the addition of butorphanol to the immobilizing mixture on the cardiopulmonary effects in free-ranging white rhinoceroses darted from the helicopter. In the control group (n=15), the rhinoceroses were anesthetized with etorphine, azaperone, detomidine, and hyaluronidase administered intramuscularly. In the treatment group (n=16), 10-20 mg of butorphanol was added to the combination. Within 10 min of becoming immobile, vital parameters (heart rate, respiratory rate, and temperature) and blood gas analyses were taken, and measurements were repeated after 10 (treatment group) and 20 min (control group). Both groups showed respiratory and metabolic acidosis, hypoxemia, and hypercapnia. In the control group, the arterial partial pressure of oxygen was significantly higher and the alveolar-to-arterial oxygen pressure gradients were significantly lower in all body positions compared with the butorphanol group. Oxygen hemoglobin saturation in the control group was higher than in the butorphanol group only in the lateral position. Improvements in arterial oxygen levels were observed in all animals when placed in sternal recumbency. There were no significant differences in the mean induction times between groups, but the distance the butorphanol group ran was significantly less after darting than in the control group. By adding butorphanol to the immobilizing mixture, no benefits in ventilation were seen; although, size differences make comparisons difficult. Running for a shorter distance during induction could be beneficial in the prevention of severe acid-base imbalances and capture myopathy.  相似文献   

13.
Mechanical ventilation of a cloned calf in respiratory failure   总被引：1，自引：0，他引：1  
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14.
Anesthesia of equids is associated with pulmonary dysfunction. Cardiovascular and respiratory effects of inhalation anesthetic agents and duration of anesthesia have been studied, using oxygen as the carrier gas. To our knowledge, the effects of inspired oxygen have not been determined. We studied the cardiovascular and respiratory effects of 2 inspired oxygen fractions (0.30 and greater than 0.85) in 5 laterally recumbent, halothane-anesthetized horses. Mean systemic arterial blood pressure, cardiac output, central venous pressure, pulmonary arterial pressure, arterial pH, and arterial base excess were similar in horses of the 2 groups during 4 hours of anesthesia at constant end-tidal halothane concentration. End-tidal partial pressure of CO2, arterial partial pressure of CO2 and O2, and alveolar-to-arterial O2 tension difference were greater in horses exposed to the higher oxygen concentration. On the basis of the data obtained, we suggest that greater hypoventilation and ventilation/perfusion mismatch occur when horses are breathing high-oxygen fraction. Arterial partial pressure of O2 was not different between the 2 groups of horses after they were disconnected from the anesthesia circuit and allowed to breathe room air. Horses recovered from anesthesia without complications.  相似文献   

15.
Objective – To describe the successful management of an alpaca with severe hypoventilation and hypercapnia, suspected to be secondary to an anesthesia‐related event. Case Summary – A 3‐year‐old, female alpaca underwent a routine eye enucleation under general anesthesia after traumatic globe perforation. Severe hypoventilation and associated hypercapnia developed postoperatively resulting in a severe primary respiratory acidosis. The awake alpaca was supported with positive‐pressure ventilation for approximately 20 hours before successful weaning. Recovery to hospital discharge occurred over the subsequent 5 days with the alpaca regaining apparently normal respiratory function. New or Unique Information Provided – To the knowledge of the authors, this is the first report describing positive‐pressure ventilation of an alpaca in the veterinary literature. In this case of severe hypoventilation, ventilatory support was essential to the positive outcome. As South American camelids continue to increase in popularity there may be an increased demand for high‐quality and sophisticated veterinary care for these animals. Mechanical ventilation can be used to help restore and maintain normal PO2, PCO2, and respiratory acid‐base status in alpacas with ventilatory dysfunction.  相似文献   

16.
With respiratory therapy in critically ill veterinary patients becoming more commonplace, a consistent Indicator of pulmonary function status is necessary. Although calculation of the pulmonary shunt fraction correlates well with the degree of pulmonary dysfunction, lts detetmination requires placement of a pulmonary arterial catheter, an invasive procedure that may not be practical in many clinical situations. Using Information obtained from the atterial blood gas, many other oxygen-tension derived Indices have been suggested as noninvasive measurements of the efficiency of pulmonary gas exchange, lncluding the alveoiar-arterial oxygen tension difference, the ratio of arterial to alveolar oxygen tension, the ratio of arterial to inspired oxygen tension, and the ratio of alveolar-arterial gradient to arterial oxygen tension. A total of 427 blood gas values from 195 different patients were evaluated. A loglstic regression model using a stepwise algorithm was constructed to assess potential multicollinearity and interaction between factors. The only factors that contributed significantly to the model predictive of survival were age (p < 0.015), base excess (p < 0.029), and the alveolar-arterial oxygen tension difference (p < 0.014).  相似文献   

17.
Objective: To discuss a new clinical presentation of organophosphate toxicity called the intermediate syndrome in a dog. Case summary: A mixed breed dog presented with generalized weakness, hypoventilation and hypoxemia. The weakness was most marked in the thoracic limbs, cervical and respiratory muscles. The history revealed a likely exposure to an organophosphate compound. The other dog in the household demonstrated mild clinical signs of organophosphate toxicity. A blood cholinesterase level was markedly reduced. Therapy included placement of a tracheostomy tube and mechanical ventilation. The dog gradually improved over the following 8 days but had persistent cervical ventroflexion for a total of 4 weeks. New or unique information provided: Organophosphate toxicity can present as a paralysis following the acute cholinergic crisis. The muscular weakness predominantly affects the thoracic limb and neck muscles but cranial nerve deficits can also occur. Dogs can die from the associated respiratory depression. Oxime therapy is indicated in the treatment of this syndrome.  相似文献   

18.
We report the use of a balanced anesthetic technique in a three-year-old, female Huacaya alpaca with an increased anesthetic risk that underwent an extensive dental surgery. Anesthesia was provided with an infusion of midazolam, fentanyl, S-ketamine and low concentrations of isoflurane in oxygen. The mandibular alveolar nerve was desensitized with a lidocaine-bupivacaine combination. The alpaca showed signs of hypoxemia fifteen minutes after anesthesia induction and arterial blood gases confirmed severe venous admixture. Application of positive end expiratory pressure (PEEP) of 6-9 cm H2O improved the arterial oxygenation. Other cardiopulmonary variables remained within the normal range. At the end of surgery, sarmazenil was administered to antagonize the effects of midazolam and emergence from anesthesia was smooth and uneventful. Flunixine meglumine and a transdermal delivery system for fentanyl were administered for post-operative analgesia. This method of balanced anesthesia allowed for an adequate anesthetic plane and a safe recovery, however, special ventilation strategies (PEEP) had to be applied.  相似文献   

19.
"Shaker foal" disease, toxicoinfectious botulism of foals, was 1st described as a clinical entity in 1967. The reported mortality rate was 90%, with death occurring within 24-72 hours of the onset of the characteristic clinical signs. The mortality rate decreased when equine-origin botulism antitoxin became available; however, a certain percentage of foals continued to die of respiratory failure. Mechanical ventilation is an important part of the treatment of infant botulism and is essential to the survival of many affected infants. We report a retrospective study of 9 foals with toxicoinfectious botulism where early mechanical ventilation was employed as part of the treatment. Foals receiving mechanical ventilation were progressively acidemic and had increased PaCO2 tensions before mechanical ventilation. These arterial blood gas abnormalities were ameliorated with mechanical ventilation. One foal was euthanized for economic reasons; survival in treated foals was 87.5%. Mechanical ventilation of foals with botulism and respiratory failure appears to be an effective therapy.  相似文献   

20.
Ventilation-perfusion relationships in the anaesthetised horse   总被引：1，自引：0，他引：1  
Ventilation-perfusion relationships were studied by the multiple inert gas elimination technique in seven horses while they were conscious and during inhalation anaesthesia with halothane. A generally good match between ventilation and perfusion was found in the conscious, standing horse. During anaesthesia a huge shunt developed, ie perfusion of completely unventilated lung regions, both in dorsal and left lateral recumbency and whether the horse was breathing spontaneously or mechanically ventilated. The shunt was significantly greater and the arterial oxygen tension (PaO2) significantly lower in dorsal than in left lateral recumbency. Little or no perfusion of low VA/Q regions was observed during anaesthesia, whether ventilation was spontaneous or mechanical. Positive end-expiratory pressure (PEEP) did not significantly improve PaO2 or reduce the shunt. Selective mechanical ventilation of dependent lung regions with PEEP reduced the shunt markedly, an effect that was not achieved by conventional mechanical ventilation with general PEEP. The findings seem compatible with alveolar collapse during anaesthesia, causing shunt, whereas the absence of clearly low VA/Q regions questions the role of airway closure as the major disturbance of gas exchange.  相似文献   

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