https://novaprd-lb.newcastle.edu.au/vital/access/manager/Index ${session.getAttribute("locale")} 5 Cardioselective inhibition of sympathetic control by atenolol in man does not evoke fatigue: a double-blind study https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:12753 Wed 24 Jul 2013 22:24:43 AEST ]]> The effect of haemorrhagic shock and resuscitation on fracture healing in a rabbit model: An animal study https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:41656 Wed 10 Aug 2022 10:49:25 AEST ]]> Reamed locked intramedullary nailing for studying femur fracture and its complications https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:33926 Wed 04 Sep 2019 09:55:58 AEST ]]> Analysis of bronchovascular downstream blood pressure changes in exercising sheep https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1393 Sat 24 Mar 2018 08:28:02 AEDT ]]> Neural control of the bronchial circulation https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1396 Sat 24 Mar 2018 08:28:01 AEDT ]]> Long-term measurement of bronchial vascular resistance in awake sheep and dogs https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1392 Sat 24 Mar 2018 08:27:59 AEDT ]]> Autonomic control of bronchial blood flow and airway dimensions during strenuous exercise in sheep https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:12114 br) and dimensions during moderate and strenuous exercise, and to analyse the role of vagal and sympathetic nerves. Methods: Nine ewes (34–44 kg) underwent left thoracotomy during general anaesthesia (thiopentone/isoflurane) and either (5 sheep = Group 1) a pulsed Doppler transducer was placed on the bronchial artery, or (4 sheep = Group 2) a pulsed Doppler transducer was placed on the bronchial artery, and transit-time and single crystal sonomicrometers were mounted on the left main bronchus. These measured continuously Qbr, bronchial circumference (Circbr) and wall thickness (Thbr). Aortic pressure (Pa) and central venous pressure catheters were placed in the superficial cervical artery and vein. Trained sheep exercised on a horizontal treadmill, i.e. Group 1, moderate exercise 2.2 mph over 1.6, 6 min recovery, for analysis of changes in Qbr before and after cholinoceptor blockade; Group 2, strenuous exercise 4.4 mph over 2, 10 min recovery for analysis of changes in Qbr and airway dimensions, before and after cholinoceptor plus α1-, α2-adrenoceptor blockade. β-adrenoceptor systems were intact. Results: In Group 1 during moderate exercise Pa and heart rate (HR) rose. Qbr and blood flow conductance (Cbr) fell immediately to 83% (P<0.001) before returning toward resting levels, but fell when exercise ceased to 89% (P<0.01) before recovering. Prior cholinoceptor blockade abolished the immediate fall in Qbr and Cbr, but not the recovery vasoconstriction. Later in recovery the bronchial bed dilated progressively over 6 min (P<0.05). In Group 2 during strenuous exercise Pa and HR rose substantially. Qbr and Cbr fell to 68% and 54% (P<0.001), respectively, and there was early vasoconstriction in recovery. Circbr fell immediately and remained at 93% (P<0.01), and did not recover fully when exercise ceased. Thbr did not change during or after exercise. Prior cholinoceptor plus α-adrenoceptor block caused Pa and Qbr to fall slightly during exercise, but the bronchovascular constriction during and after exercise was abolished, as was circumferential shortening in the airway. Conclusions: At exercise onset and steady-state, resetting the arterial baroreflex upward in sheep increases parasympathetic cholinergic vasoconstrictor activity and causes bronchial wall and bronchovascular smooth muscle contraction in concert with sympathetic adrenergic constriction of systemic vascular beds. Whether the known sigmoid baroreflex control of tracheal smooth muscle tension at rest is extended to tracheobronchial smooth muscle and its circulation during exercise is yet to be determined.]]> Sat 24 Mar 2018 08:13:00 AEDT ]]> Integration of baroreflex and autoregulation control of bronchial blood flow in awake dogs https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:11792 Q = 0.034 + 0.00033(XPg − 104.6). The regression fell on the line of equal proportional change. Conclusion: Baroreflexes do not functionally engage the autonomic outflow to the bronchial circulation. Under controlled conditions of systemic Pg change, the bronchial circulation is normally controlled by the integration of resting autonomic tone, myogenic autoregulation and pressure-passive effects.]]> Sat 24 Mar 2018 08:10:21 AEDT ]]> Effects of graded exercise on bronchial blood flow and airway dimensions in sheep https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:12192 br) and conductance (Cbr), bronchial circumference (Circbr) and wall thickness (Thbr). In Protocol 1 (P1), four sheep ran duplicate 5 min protocols on a horizontal treadmill at continuous step-up-and-down speeds of 1 min duration, namely, 0.8, 1.6, 2.2, 1.6 and 0.8 mph (moderate exercise), followed by 10 min recovery. In P2, four sheep ran duplicate 2 min protocols at constant 4 mph (strenuous exercise), and in P3, one sheep ran duplicate protocols each of 3 min at 2.2, 4.4 and 6 mph (severe exercise). Regression analysis and repeated measures ANOVA were used to assess differences between times, runs and exercise intensity. In P1, airway effects were directly related to graded exercise effort sustained over 5 min. Peak effects occurred at 2.2 mph, except for Thbr. Heart rate and Pa rose (to 156% and 111% of resting, respectively), and Qbr and Cbr fell (to 83% and 75%; both P<0.001). Circbr fell to 96% (P=0.02), and Thbr rose at low speeds early and late, and thinned at the highest speed. In P2 and P3 for all variables the steady-state effects were systematically greater than for P1 (4.4 mph: Cbr to 43%, Circbr to 93%; 6.6 mph: Cbr to 25%, Circbr to 82%). There was no significant recovery hyperaemia, but there was residual post-exercise bronchoconstriction. The exercise stimulus–response relationships from rest to a maximal 6 mph for sheep airway circumference and its bronchial circulation are inverse and functionally constrictor.]]> Sat 24 Mar 2018 08:08:28 AEDT ]]> Cardiac afferent control of bronchial flow in awake dog https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:22754 BR), and intrapericardial (IPC) catheters were placed in pericardial sac for drug infusion. Arterial and central venous catheters were placed in omocervical vessels for measurement of blood pressures. IPC infusion of 2% procaine (16 mgkg-1) significantly (all P<0.05) raised resting heart rate (HR, to 210% of control), aortic pressure (Pa, 115%), QBR (146%) and bronchial flow conductance (CBR, 125%). In 6 dogs, IPC nicotine (0.5-16μgkg-1) produced transient bradycardia and hypotension, characteristic of vagal afferent stimulation in anesthetised dogs, before significantly (all P<0.05) raising HR (114%), Pa (121%), QBR (142%) and CBR(126%) 80 seconds after injection. IPC veratridine (2-20μg) significantly (all P<0.05) raised HR (134%), Pa(108%), QBR (164%) and CBR (155%) at 65 seconds. Responses to both stimuli were blocked by prior IPC application of procaine. The results suggest that cardiac sympathetic afferents tonically constrict the bronchial circulation at rest in the awake dog. Further, the chemical stimuli used cause non-specific activation of both sympathetic and vagal afferents to evoke a mixed cardiovascular response where a dilator mechanism prevails in the bronchial circulation, and a sympathoexcitatory effect in the systemic circulation. The findings are relevant to pulmonary congestion in heart failure syndromes.]]> Sat 24 Mar 2018 07:14:16 AEDT ]]> Effect of high-flow vs. low-flow nasal plus mouthguard oxygen therapy on hypoxaemia during sedation: a multicentre randomised controlled trial https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:49172  30 kg.m-2 or with known or suspected obstructive sleep apnoea were randomly allocated to high-flow nasal oxygen up to 60 l.min-1 at 100% FI O2 or low-flow nasal oxygen at 4 l.min-1 . The low-flow nasal oxygen group also received oxygen at 4 l.min-1 through an oxygenating mouthguard, totalling 8 l.min-1 . Primary outcome was hypoxaemia, defined as Sp O2 < 90% regardless of duration. Hypoxaemia occurred in 7.7% (5/65) of patients with high-flow and 9.1% (6/66) with low-flow nasal oxygen (percentage point difference -1.4%, 95%CI -10.9 to 8.0; p = 0.77). Between the groups, there were no significant differences in frequency of hypoxaemic episodes; lowest Sp O2 ; peak transcutaneous carbon dioxide; hypercarbia (transcutaneous carbon dioxide > 2.66 kPa from baseline); requirement of chin lift/jaw thrust; nasopharyngeal airway insertion; bag-mask ventilation; or tracheal intubation. Following adjustment for duration of the procedure, the primary outcome remained non-significant. In high-risk patients undergoing endoscopic retrograde cholangiopancreatography, oxygen therapy with high-flow nasal oxygen did not reduce the rate of hypoxaemia, hypercarbia or the need for airway interventions, compared with combined oral and nasal low-flow oxygen.]]> Fri 05 May 2023 15:37:55 AEST ]]>