A study of cardiovascular function under controlled and spontaneous ventilation in isoflurane–medetomidine anaesthetized horses

Kalchofner, Karin; Picek, Stephanie; Ringer, Simone K; Jackson, Michelle; Hässig, Michael; Bettschart‐Wolfensberger, Regula

doi:10.1111/j.1467-2995.2009.00477.x

Cited by 37 publications

(35 citation statements)

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“…A few reasons might have contributed to these results: a) the horses were mechanically ventilated to maintain normocapnia; b) the horses were not subjected to noxious stimulation. In horses anesthetized under mechanical ventilation, cardiovascular depression is expected to occur unless the ventilation is adjusted to allow mild hypercapnia, considered as PaCO2 values of 50-60mmHg (KALCHOFNER et al, 2009). Also, it has been reported that in horses anesthetized for surgical procedures, DBT was effective in improving cardiovascular performance (DE VRIES et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Influence of acepromazine on the cardiovascular actions of dobutamine in isoflurane-anesthetized horses

et al. 2011

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Section: Discussionmentioning

confidence: 99%

Influence of acepromazine on the cardiovascular actions of dobutamine in isoflurane-anesthetized horses

et al. 2011

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“…Several authors have recognized these detrimental effects of mechanical ventilation in horses (Hodgson et al 1986, Steffey et al 1992, Mizuno et al 1994, Edner et al 2005) while others have found no or minimal detrimental effects on cardiovascular parameters when using IPPV with or without PEEP (Swanson and Muir 1988, Wettstein et al 2006, Bringewatt et al 2010, Hopster et al 2011, Ambrosio et al 2013. One other study found these cardiovascular effects to be negligible when providing mild hypercapnia (Kalchofner et al 2009). Whether and to which degree the cardiovascular system will be impaired appears to be greatly influenced by pressures used and the time over which high PIP and PEEP pressures are applied.…”

Section: Introductionmentioning

confidence: 99%

The use of positive end-expiratory pressure (PEEP) and alveolar recruitment manoeuvre (ARM) in equine anaesthesia – a review

Küls¹,

Braun²,

Moens³

2016

PHK

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Summary: Impairment of gas exchange and arterial oxygenation during general anaesthesia and recumbency of the horse are a common and well-known problem. Often these alterations are poorly responsive to intermittent positive pressure ventilation (IPPV) and increasing levels of supplemental oxygen. Over the last decades the understanding of the underlying pathophysiology developed more and more, recognizing that a decrease in functional residual capacity (FRC), lung collapse and atelectasis, and ultimately ventilation/perfusion mismatch lead to poor oxygenation. Accordingly, new ventilation strategies arose over the course of time including alveolar recruitment manoeuvres (ARMs) and positive end expiratory pressure (PEEP). In 1992 Burkhard Lachmann presented his idea of an 'open lung' concept using high peak inspiratory pressures to reopen atelectatic lung regions followed by sufficiently high PEEP to keep the recruited lung areas open. In equine anaesthesia, early attempts with continuous positive pressure in spontaneously breathing horses yielded rather disappointing results. In combination with IPPV the use of PEEP resulted in unreliable improvements in the partial pressure of oxygen in arterial blood (PaO 2 ). Once the pre-treatment with an ARM prior to PEEP was introduced, improvement in PaO 2 could be seen to be more reliable. Despite these promising results, there is a risk of adverse effects with the use of PEEP and ARM in horses due to the high pressures that are necessary to achieve an effect. A reduction in cardiac output proportional to the increase in intrathoracic pressure has been observed and may compromise peripheral blood flow as well as gastrointestinal perfusion once a certain pressure threshold is reached. Similar, an increase in right to left shunt due to forcing blood into already collapsed lung areas can compromise the desired effect. Finally, early signs of ventilator induced lung injury have been detected in horses and it remains to be seen how future ventilation strategies will succeed in finding the optimal balance for each individual horse. This review presents the development and use of ARMs and PEEP in horses and its potential effect and side effects.

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“…It supports lung function by eliminating carbondioxide and allowing oxygenisation of arterial blood. It increases tidal volume and enables atelectatic alveoli to regain their function 2,3,[5][6][7] .…”

mentioning

confidence: 99%

“…Over-inflation of the alveoli leads to formation of pulmonary interstitial emphysema, pneumomediastinum and pneumothorax 6,8 . Due to increasing thoracic pressure, right ventricular dysfunction, altered left ventricular distensibility and low cardiac output, IPPV decreases venous return to the heart 2,3,5,6,9 .…”

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confidence: 99%

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Comparison of the Effects of Spontaneous and Mechanical Ventilation on Blood Gases During General Anaesthesia in Dogs

Güzel¹,

Yıldar²,

Karabağli³

et al. 2013

Kafkas Univ Vet Fak Derg

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SummarySpontaneous ventilation during general anaesthesia leads to respiratory depression and atelectasis. Mechanical ventilation increases tidal volume and eliminates atelectasis. The study material consisted of a total of 20 dogs of different breed, age and gender. Dogs were divided into two groups, consisted of 10 dogs. The first group was established as the spontaneous ventilation (SV) group, while the second group was the mechanical ventilation (MV) group. For induction of anaesthesia, propofol was administered to both groups via intravenous injection at a dose of 6 mg/kg. Blood samples were collected from all dogs in 5 minutes after propofol administration. This period was determined as Minute 0 (T 0 ). In both groups, inhalation anaesthesia was continued with isoflurane. Venous blood samples were collected from dogs in the SV and MV groups at 15 (T 15 ), 30 (T 30 ) and 60 (T 60 ) minutes. Heart rate, respiratory rate, SpO 2 , body temperature and blood gases were monitored. Statistical evaluation of the study was carried out using the Repeated Measures Analysis of Variance method. The results obtained showed that there was no statistically significant difference between the SV and MV groups regarding the examined parameters. However, in the assessments within the group, results obtained from the dogs in the MV group were more reliable from the point of view of the patients remaining stable throughout anaesthesia. Keywords: Spontaneous ventilation, Mechanical ventilation, Blood gases, Dog Köpeklerde Genel Anestezi Sürecinde Spontan ve Mekanik Ventilasyonun Kan Gazları Üzerine Etkilerinin Karşılaştırılması ÖzetGenel anestezide spontan ventilasyon, solunumun baskılanmasına ve atelektaziye yol açar. Mekanik ventilasyon tidal volümü artırır ve atelektaziyi giderir. Çalışma materyalini, farklı ırk, yaş ve cinsiyetteki toplam 20 köpek oluşturdu. Olgular, her grupta 10 köpek olacak şekilde 2'ye ayrıldı. İlk grup spontan ventilasyon (SV), ikinci grup mekanik ventilasyon (MV) grubu olarak belirlendi. Anestezi indüksiyonunda her iki gruba, propofol 6 mg/kg'dan intravenöz enjeksiyonla verildi. Tüm köpeklerden, propofol enjeksiyonunu takip eden 5. dakikada kan örnekleri alındı. Bu süre 0. dakika (T 0 ) olarak değerlendirildi. Her iki grubun inhalasyon anestezisi izofloranla sürdürüldü. SV ve MV grubundaki olgulardan 15. dakika (T 15 ), 30. dakika (T 30 ) ve 60. dakika (T 60 )'larda venöz kan örnekleri alındı. Kalp atım sayısı, solunum sayısı, SpO 2 , vücut ısısı ve kan gazları monitörize edildi. Çalışmanın istatistiki değerlendirmesi Tekrarlı Ölçüm Varyans Analizi metodu ile yapıldı. Elde edilen bulgular, incelenen parametreler yönünden SV ve MV grupları arasında istatistiki anlamda önemli bir fark olmadığını gösterdi. Ancak grup içi değerlendirmelerde, MV grubundaki köpeklerden elde edilen sonuçların, hastaların anestezi süresince stabil kalmaları açısından daha güvenilir olduğu sonucuna ulaşıldı.

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A study of cardiovascular function under controlled and spontaneous ventilation in isoflurane–medetomidine anaesthetized horses

Cited by 37 publications

References 27 publications

Influence of acepromazine on the cardiovascular actions of dobutamine in isoflurane-anesthetized horses

Influence of acepromazine on the cardiovascular actions of dobutamine in isoflurane-anesthetized horses

The use of positive end-expiratory pressure (PEEP) and alveolar recruitment manoeuvre (ARM) in equine anaesthesia – a review

Comparison of the Effects of Spontaneous and Mechanical Ventilation on Blood Gases During General Anaesthesia in Dogs

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