Cardio-renal recovery of hypoxic newborn pigs after 18%, 21% and 100% reoxygenation

Cheung, Po-Yin; Obaid, Laila; Emara, Marwan; Brierley, Yann; Johnson, Scott T.; Chan, Grace S.; Jewell, Laurence D.; Korbutt, Gregory S.; Bigam, David L.

doi:10.1007/s00134-008-1008-9

Cited by 14 publications

(9 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…3 However, concerns have been raised about the potential adverse effects of increased fraction of inspired oxygen within the first 6 hours of life in newborns treated with therapeutic hypothermia. [34][35][36] In the current study, only 3/8 piglets in the SI group required 100% oxygen during CPR in comparison with all 8/8 piglets in the 3:1 group. This is of important clinical relevance, because hyperoxia slows cerebral blood flow and can lead to the generation of oxygen-free radicals, a major cause in reperfusion injury after asphyxia.…”

Section: Discussionmentioning

confidence: 51%

Cardiopulmonary Resuscitation With Chest Compressions During Sustained Inflations

et al. 2013

Self Cite

View full text Add to dashboard Cite

Background-Guidelines on neonatal resuscitation recommend 90 chest compressions (CCs) and 30 manual inflations (3:1) per minute in newborns. The study aimed to determine whether CC s during sustained inflations (SIs) improves the recovery of asphyxiated newborn piglets in comparison with coordinated 3:1 resuscitation. Methods and Results-Term newborn piglets (n=8/group) were anesthetized, intubated, instrumented, and exposed to 45-minute normocapnic hypoxia followed by asphyxia. Piglets were randomly assigned to receive either 3:1 resuscitation (3:1 group) or CCs during SIs (SI group) when the heart rate decreased to 25% of baseline.

show abstract

Section: Discussionmentioning

confidence: 51%

Cardiopulmonary Resuscitation With Chest Compressions During Sustained Inflations

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Indeed, we have been succesful in modifying the experimental protocol to extended subacute (e.g. 48-72 hours) 12 , survival (5-7 days) 13 as well as chronically instrumented studies. In these prolonged protocols, careful hypoxia and intensive medical and nursing care are important to minimize the mortality and morbidity.…”

Section: Discussionmentioning

confidence: 99%

A Swine Model of Neonatal Asphyxia

Cheung

Gill

Bigam

2011

JoVE

Self Cite

View full text Add to dashboard Cite

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, perfusion deficit, hypoxic-ischemic encephalopathy, pulmonary hypertension, vasculopathic enterocolitis, renal failure and thrombo-embolic complications. Animal models are developed to help us understand the patho-physiology and pharmacology of neonatal asphyxia. In comparison to rodents and newborn lambs, the newborn piglet has been proven to be a valuable model. The newborn piglet has several advantages including similar development as that of 36-38 weeks human fetus with comparable body systems, large body size (˜1.5-2 kg at birth) that allows the instrumentation and monitoring of the animal and controls the confounding variables of hypoxia and hemodynamic derangements.We here describe an experimental protocol to simulate neonatal asphyxia and allow us to examine the systemic and regional hemodynamic changes during the asphyxiating and reoxygenation process as well as the respective effects of interventions. Further, the model has the advantage of studying multi-organ failure or dysfunction simultaneously and the interaction with various body systems. The experimental model is a non-survival procedure that involves the surgical instrumentation of newborn piglets (1-3 day-old and 1.5-2.5 kg weight, mixed breed) to allow the establishment of mechanical ventilation, vascular (arterial and central venous) access and the placement of catheters and flow probes (Transonic Inc.) for the continuously monitoring of intra-vascular pressure and blood flow across different arteries including main pulmonary, common carotid, superior mesenteric and left renal arteries. Using these surgically instrumented piglets, after stabilization for 30-60 minutes as defined by Z<10% variation in hemodynamic parameters and normal blood gases, we commence an experimental protocol of severe hypoxemia which is induced via normocapnic alveolar hypoxia. The piglet is ventilated with 10-15% oxygen by increasing the inhaled concentration of nitrogen gas for 2h, aiming for arterial oxygen saturations of 30-40%. This degree of hypoxemia will produce clinical asphyxia with severe metabolic acidosis, systemic hypotension and cardiogenic shock with hypoperfusion to vital organs. The hypoxia is followed by reoxygenation with 100% oxygen for 0.5h and then 21% oxygen for 3.5h. Pharmacologic interventions can be introduced in due course and their effects investigated in a blinded, block-randomized fashion. Video LinkThe video component of this article can be found at http://www.jove.com/details.php?id=3166 Protocol 1. Anesthesia 1. Set the flow rate of the anesthetic machine at 2L/min. Connect the exhaust to vacuum suction. 2. Charge face mask with anesthetic gas (Isoflurane) at 5% (˜3 min). 3. Newborn piglets will be induced with inhaled Isoflurane 5% in 100% oxygen (˜3 min). 4. Maintain anesthesia at 2-3% of Isoflurane. Fine adjustment of Isoflurane by 0.5% as appropriate, however, it may ran...

show abstract

“…Thus, a moderate adaptation of the autonomous system due to the restricted oxygen supply during late normocapnic hypoxia is already present. During reoxygenation, regulating mechanisms related to ventilation are prolonged and ongoing, presumably due to an unstabilised blood acid-base balance [38-40]. By contrast, the adaptation of HRV, BPV and cardiovascular interactions proceed much faster and seem to play a superior role in the autonomous regulatory process.…”

Section: Discussionmentioning

confidence: 99%

Quantification of compensatory processes of postnatal hypoxia in newborn piglets applying short-term nonlinear dynamics analysis

et al. 2011

View full text Add to dashboard Cite

BackgroundNewborn mammals suffering from moderate hypoxia during or after birth are able to compensate a transitory lack of oxygen by adapting their vital functions. Exposure to hypoxia leads to an increase in the sympathetic tone causing cardio-respiratory response, peripheral vasoconstriction and vasodilatation in privileged organs like the heart and brain. However, there is only limited information available about the time and intensity changes of the underlying complex processes controlled by the autonomic nervous system.MethodsIn this study an animal model involving seven piglets was used to examine an induced state of circulatory redistribution caused by moderate oxygen deficit. In addition to the main focus on the complex dynamics occurring during sustained normocapnic hypoxia, the development of autonomic regulation after induced reoxygenation had been analysed. For this purpose, we first introduced a new algorithm to prove stationary conditions in short-term time series. Then we investigated a multitude of indices from heart rate and blood pressure variability and from bivariate interactions, also analysing respiration signals, to quantify the complexity of vegetative oscillations influenced by hypoxia.ResultsThe results demonstrated that normocapnic hypoxia causes an initial increase in cardiovascular complexity and variability, which decreases during moderate hypoxia lasting one hour (p < 0.004). After reoxygenation, cardiovascular complexity parameters returned to pre-hypoxic values (p < 0.003), however not respiratory-related complexity parameters.ConclusionsIn conclusion, indices from linear and nonlinear dynamics reflect considerable temporal changes of complexity in autonomous cardio-respiratory regulation due to normocapnic hypoxia shortly after birth. These findings might be suitable for non-invasive clinical monitoring of hypoxia-induced changes of autonomic regulation in newborn humans.

show abstract

Cardio-renal recovery of hypoxic newborn pigs after 18%, 21% and 100% reoxygenation

Cited by 14 publications

References 30 publications

Cardiopulmonary Resuscitation With Chest Compressions During Sustained Inflations

Cardiopulmonary Resuscitation With Chest Compressions During Sustained Inflations

A Swine Model of Neonatal Asphyxia

Quantification of compensatory processes of postnatal hypoxia in newborn piglets applying short-term nonlinear dynamics analysis

Contact Info

Product

Resources

About