Comparison of respiratory function during TIVA and isoflurane anaesthesia in ponies Part II: breathing patterns and transdiaphragmatic pressure. (2nd July 2014)

• Record Type: Journal Article
• Authors: Kowalczyk, Lidia; Steblaj, Barbara; Schauvliege, Stijn; Schramel, Johannes Peter; Pavlidou, Kiriaki; Savvas, Ioannis; Duchateau, Luc; Gasthuys, Frank; Moens, Yves
• Is Part Of: Veterinary anaesthesia and analgesia. Volume 41:Number 6(2014:Nov.)
• Page Start: 592
• Page End: 601
• Publication Date: 2014-07-02
• Subjects: Veterinary anesthesia -- Periodicals; 636.089
• DOI: 10.1111/vaa.12151
• Languages: English
• ISSNs: 1467-2987

Abstract

<abstract abstract-type="main" id="vaa12151-abs-0001"> <title>Abstract</title> <sec id="vaa12151-sec-0001" sec-type="section"> <title>Objective</title> <p>To compare breathing patterns and transdiaphragmatic pressure during total intravenous (TIVA) and isoflurane anaesthesia in ponies.</p> </sec> <sec id="vaa12151-sec-0002" sec-type="section"> <title>Study design</title> <p>Experimental, cross–over study.</p> </sec> <sec id="vaa12151-sec-0003" sec-type="section"> <title>Animals</title> <p>Six healthy ponies weighing 286 (233–388) ± 61 kg, age 13 (9–16) ± 3 years.</p> </sec> <sec id="vaa12151-sec-0004" sec-type="section"> <title>Methods</title> <p>Following premedication with romifidine [80 μg kg<sup>−1</sup> intravenously (IV)], general anaesthesia was induced with midazolam (0.06 mg kg<sup>−1</sup> IV) and ketamine (2.5 mg kg<sup>−1</sup> IV) and maintained with either isoflurane (F<sc>e</sc>′Iso = 1.1%) (T‐ISO) or an IV combination of romifidine (120 μg kg<sup>−1</sup> per hour), midazolam (0.09 mg kg<sup>−1</sup> hour<sup>−1</sup>) and ketamine (3.3 mg kg<sup>−1</sup> hour<sup>−1</sup>) (T‐TIVA), while breathing 60% oxygen (FIO<sub>2</sub>). The circumference changes of the rib cage (RC) and abdominal compartment (ABD) were recorded using respiratory ultrasonic plethysmography (RUP). Balloon tipped catheters were placed in the distal oesophagus and the stomach and maximal transdiaphragmatic pressure (P<sub>di max)</sub> was calculated during Mueller's manoeuvre.</p> </sec> <sec id="vaa12151-sec-0005" sec-type="section"> <title>Results</title> <p>The breathing pattern T‐ISO was more regular and respiratory rate significantly lower compared with T‐TIVA. Ponies in T‐TIVA showed regularly appearing sighs, which were never observed in T‐ISO. Different contribution of the RC and ABD compartments to the breathing pattern was observed with a smaller participation of the RC to the total volume change during T‐ISO. Transdiaphragmatic pressures (mean 13.7 ± SD 8.61 <italic>versus</italic> 23.4 ± 7.27 cmH<sub>2</sub>O, <italic>p</italic> < 0.0001) were higher in T‐TIVA compared to T‐ISO. The sum of the RC and ABD circumferential changes was lower during T‐TIVA compared to T‐ISO (6.32 ± 4.42 <italic>versus</italic> 11.72 ± 4.38 units, <italic>p</italic> < 0.0001).</p> </sec> <sec id="vaa12151-sec-0006" sec-type="section"> <title>Conclusion and clinical relevance</title> <p>Marked differences in breathing pattern and transdiaphragmatic pressure exist during inhalation‐ and TIVA and these should be taken into account for clinical estimation of anaesthetic depth.</p> </sec> </abstract>