A comparison between medetomidine-ketamine and medetomidine-propofol anaesthesia in rabbits

1997 ◽  
Vol 31 (1) ◽  
pp. 58-69 ◽  
Author(s):  
Ludo J. Hellebrekers ◽  
Evert-Jan W. de Boer ◽  
Michiel A. van Zuylen ◽  
Hans Vosmeer
Keyword(s):  
Muscle Tone ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Physiological Variables ◽  
Arterial Blood ◽  
Jaw Muscle ◽  
Before And After ◽  
Anaesthetic Depth ◽  
Low Incidence ◽  
High Degree

We investigated the effects of combinations of the α2-agonist medetomidine with either ketamine or propofol for their overall quality of anaesthesia, including the possible concomitant changes in respiratory and circulatory function in New Zealand White rabbits. Medetomidine was administered at 0.35 mg/kg, intramuscularly. Following sedation, ketamine (5 mg/kg) or propofol (2 and 3 mg/kg) were administered intravenously via the ear vein. Data on reflexes (palpebral, corneal, ear-pinch and toe-pinch), jaw muscle tone and physiologic parameters (heart rate, blood pressure, respiration rate, body temperature) were recorded before and after administration of drugs. Intermittent arterial blood sampling was performed at predetermined intervals before and after anaesthesia. The results show that the ear-pinch and toe-pinch reflexes and the jaw muscle tone are reliable indices to determine surgical anaesthetic depth. A surgical level of anaesthesia could be obtained reliably with the combination medetomidine-ketamine and medetomidine-propofol (3 mg/kg) with a duration of 19 min (variation 10 to 40 min, n=6) and 11 min (variation 5 to 15 min, n=6), respectively. Propofol administered at 2 mg/kg did not produce an adequate anaesthetic level. The data from this study demonstrate a high degree of predictability in achieving a fast induction and adequate anaesthetic depth together with a low incidence of untoward side-effects and a zero mortality with the combinations investigated. The data from the medetomidine-ketamine group show that, although adequate anaesthetic depth of medium duration is achieved, the arterial oxygen tension is reduced to hypoxemic levels. With the use of this combination, the supplemental administration of oxygen is advised. With the combination of medetomidine-propofol (3 mg/kg) a short duration anaesthesia of adequate depth was achieved, whereby physiological variables all remained within acceptable ranges. The use of medetomidine-propofol, in combination with the α2-antagonist atipamezole to shorten recovery time, will provide reliable and very versatile anaesthesia in rabbits.

Effects of Endotracheal Tube Suctioning on Arterial Oxygen Tension and Heart Rate Variability

2006 ◽  
Vol 7 (4) ◽  
pp. 268-278 ◽  
Author(s):  
Annette M. Bourgault ◽  
C. Ann Brown ◽  
Sylvia M. J. Hains ◽  
Joel L. Parlow
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Endotracheal Tube ◽  
Oxygen Tension ◽  
Parasympathetic Nervous System ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Arterial Blood ◽  
Before And After ◽  
Open Versus

The purpose of this study was to examine the autonomic mechanisms underlying changes in heart rate (HR) and systolic blood pressure (SBP) responses to endotracheal tube (ETT) suctioning and to compare the open versus closed methods of ETT suctioning on these measures and on arterial oxygen tension. Eighteen orally intubated participants, 33 to 82 years of age (M = 60 years), were randomized for the order of suctioning method. Arterial oxygen tension (PaO2) was measured before suctioning and 30 s and 5 min following suctioning. Beat-to-beat HR and arterial blood pressure data were collected for 10-min periods before and after suctioning. HR and SBP measures were analyzed before suctioning and 1 min and 5 min following suctioning. Although there were no significant effects of ETT suctioning on the autonomic mechanisms of HR modulation and no significant differences between the two methods of suctioning, ETT suctioning resulted in an increase in HR, SBP, and PaO2. However, there was a decrease in the parasympathetic nervous system indicator of HR variability (HRV) following open suctioning. All patients in this study maintained a PaO2level 80 mm Hg, which may account for our lack of significant autonomic changes. This suggests that hyperoxygenation with 100% oxygen for a minimum of 1 min (or 20 breaths), as delivered by preoxygenation modes available on most microprocessor ventilators, should be the method of choice for all hyperoxygenation procedures to avoid a decrease in PaO2following suctioning.

ARTERIAL BLOOD GAS AND ACID-BASE DISORDERS IN INFANTS AND CHILDREN WITH STATUS ASTHMATICUS

PEDIATRICS ◽  
1968 ◽  
Vol 42 (2) ◽  
pp. 238-249
Author(s):  
John J. Downes ◽  
David W. Wood ◽  
Theodore W. Striker ◽  
Joffie C. Pittman
Keyword(s):  
Status Asthmaticus ◽  
Clinical Signs ◽  
Arterial Oxygen Tension ◽  
Base Deficit ◽  
Infants And Children ◽  
Clinical Severity ◽  
Arterial Oxygen ◽  
Acid Base ◽  
Arterial Blood ◽  
Arterial Ph

The course of arterial oxygen tension (Pao2), pH, carbon dioxide tension (Paco2) and base deficit (negative base excess) was studied in 45 episodes of status asthmaticus occurring in 32 infants and children. The data indicate that arterial hypoxemia occurs in these patients due to alveolar hypoventilation and pulmonary arterial-venous shunts. Three fourths of the patients tested demonstrated a base deficit which was related in part to ketonemia. The Paco2 varied from below normal to 168 mm Hg, and arterial pH varied from 6.89 to 7.41 at the time of peak clinical severity. Clinical signs of respiratory failure associated with a Paco2 above 65 mm Hg occurred in 13 patients (18 episodes), all of whom were successfully managed by mechanical ventilation. These studies indicate the variability in alveolar ventilation and acid-base balance during an asthmatic episode and the need for repeated assessment of arterial pH and blood gases if one is to provide optimal management.

Continuous Monitoring of Arterial Oxygen Tension Using a Catheter-Tip Polarographic Electrode in Infants

PEDIATRICS ◽  
1976 ◽  
Vol 57 (2) ◽  
pp. 244-250
Author(s):  
M. Conway ◽  
G. M. Durbin ◽  
D. Ingram ◽  
N. McIntosh ◽  
D. Parker ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Continuous Monitoring ◽  
Newborn Infants ◽  
Arterial Oxygen Tension ◽  
Oxygen Electrode ◽  
Arterial Oxygen ◽  
Respiratory Illnesses ◽  
Arterial Blood ◽  
Reliable Instrument ◽  
Catheter Tip

An oxygen electrode mounted in the tip of an umbilical artery catheter was used in 36 newborn infants with severe respiratory illnesses, 28 of whom survived. Thirty-seven electrodes were used. The median age at insertion was 4 hours (range, 30 minutes to 122 hours). Three electrodes failed to work and they were removed or replaced, and two could not be properly evaluated. Thirty-two electrodes functioned satisfactorily for 10 to 190 hours (mean, 75 hours) after a one-point calibration against blood sampled through the catheter. Twenty-two did not need recalibrating before they were removed after 10 to 190 hours (mean, 88 hours). Four of the remaining ten electrodes were recalibrated once after 33 to 97 hours and then functioned until removed 15 to 55 hours later. The other six electrodes failed after 32 to 105 hours (mean, 49 hours). Complications were few. A total of 356 arterial blood samples, obtained after the initial calibration and before any recalibration was necessary, gave a correlation coefficient of 0.93 (P < .0001) against an independent system for measuring arterial oxygen tension (Pao2) (Radiometer Type E.5046 oxygen electrode). We conclude that the catheter-tip electrode is a safe and reliable instrument for continuously recording Pao2 in newborn infants which much simplifies the management of serious respiratory illnesses.

Endotracheal suctioning: ventilator vs manual delivery of hyperoxygenation breaths

1996 ◽  
Vol 5 (3) ◽  
pp. 192-197 ◽  
Author(s):  
MJ Grap ◽  
C Glass ◽  
M Corley ◽  
T Parks
Keyword(s):  
Clinical Practice ◽  
Lung Injury ◽  
Arterial Pressure ◽  
Oxygen Saturation ◽  
Arterial Oxygen ◽  
Suction Catheter ◽  
Endotracheal Suctioning ◽  
Arterial Blood ◽  
Before And After ◽  
The Impact

BACKGROUND: Despite a large number of studies on endotracheal suctioning, there is little data on the impact of clinically practical hyperoxygenation techniques on physiologic parameters in critically ill patients. OBJECTIVE: To compare the manual and mechanical delivery of hyperoxygenation before and after endotracheal suctioning using methods commonly employed in clinical practice. METHODS: A quasi-experimental design was used, with twenty-nine ventilated patients with a lung injury index of 1.54 (mild-moderate lung injury). Three breaths were given before and after each of two suction catheter passes using both the manual resuscitation bag and the ventilator. Arterial pressure, capillary oxygen saturation, heart rate, and cardiac rhythm were monitored for 1 minute prior to the intervention to obtain a baseline, continuously throughout the procedure, and for 3 minutes afterward. Arterial blood gases were collected immediately prior to the suctioning intervention, immediately after, and at 30, 60, 120, and 180 seconds after the intervention. Data were analyzed with repeated measures analysis of variance. RESULTS: Arterial oxygen partial pressures were significantly higher using the ventilator method. Peak inspiratory pressures during hyperoxygenation were significantly higher with the manual resuscitation bag method. Significant increases were observed in mean arterial pressure during and after suctioning, with both delivery methods, with no difference between methods. Maximal increases in arterial oxygen partial pressure and arterial oxygen saturation occurred 30 seconds after hyperoxygenation, falling to baseline values at 3 minutes for both methods. CONCLUSION: Using techniques currently employed in clinical practice, these findings support the use of the patient's ventilator for hyperoxygenation during suctioning.

scholarly journals Bidirectional Ductal Shunting and Preductal to Postductal Oxygenation Gradient in Persistent Pulmonary Hypertension of the Newborn

Children ◽  
2020 ◽  
Vol 7 (9) ◽  
pp. 137
Author(s):  
Amy Lesneski ◽  
Morgan Hardie ◽  
William Ferrier ◽  
Satyan Lakshminrusimha ◽  
Payam Vali
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Blood Flow ◽  
Ductus Arteriosus ◽  
Arterial Oxygen Tension ◽  
Persistent Pulmonary Hypertension ◽  
Arterial Oxygen ◽  
Meconium Aspiration ◽  
Arterial Blood Gas ◽  
Arterial Blood

Background: The aim was to evaluate the relationship between the direction of the patent ductus arteriosus (PDA) shunt and the pre- and postductal gradient for arterial blood gas (ABG) parameters in a lamb model of meconium aspiration syndrome (MAS) with persistent pulmonary hypertension of the newborn (PPHN). Methods: PPHN was induced by intermittent umbilical cord occlusion and the aspiration of meconium through the tracheal tube. After delivery, 13 lambs were ventilated and simultaneous 129 pairs of pre- and postductal ABG were drawn (right carotid and umbilical artery, respectively) while recording the PDA and the carotid and pulmonary blood flow. Results: Meconium aspiration resulted in hypoxemia. The bidirectional ductal shunt had a lower postductal partial arterial oxygen tension ([PaO2] with lower PaO2/FiO2 ratio—97 ± 36 vs. 130 ± 65 mmHg) and left pulmonary flow (81 ± 52 vs. 133 ± 82 mL/kg/min). However, 56% of the samples with a bidirectional shunt had a pre- and postductal saturation gradient of < 3%. Conclusions: The presence of a bidirectional ductal shunt is associated with hypoxemia and low pulmonary blood flow. The absence of a pre- and postductal saturation difference is frequently observed with bidirectional right-to-left shunting through the PDA, and does not exclude a diagnosis of PPHN in this model.

Effect of Intraoperative PEEP Application on Colonic Anastomoses Healing: An Experimental Animal Study

2016 ◽  
Vol 101 (1-2) ◽  
pp. 24-34 ◽  
Author(s):  
Mehmet Akif Turkoglu ◽  
Erdal Birol Bostancı ◽  
Hasan Bilgili ◽  
Yıldız Turkoglu ◽  
Ümit Karadeniz ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Healing Process ◽  
Peep Level ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Colonic Anastomoses ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Bursting Pressures ◽  
Group 2

This study aimed to assess the effect of intraoperative positive end–expiratory pressure (PEEP) intervention on the healing of colonic anastomoses in rabbits. A total of 32 New Zealand type male rabbits were divided into 2 groups of 16 animals each. Following ventilation with tracheostomy, colonic resection and anastomosis were performed in both groups. Although 10 cm of H2O PEEP level was applied in group 1 (PEEP), group 2 [zero end-expiratory pressure (ZEEP)] was ventilated without PEEP throughout the surgery. Half of both the PEEP and ZEEP group animals were killed on the third postoperative day, whereas the remaining half were killed on the seventh. Anastomotic bursting pressures, the tissue concentrations in hydroxyproline, and histologic assessments were performed. Intraoperative oxygen saturation and postoperative arterial blood gas parameters were also compared. On the first postoperative day, both arterial oxygen tension (PO2) and oxygen saturation (SO2) in the PEEP group were significantly higher than in the ZEEP group. On the seventh postoperative day, the bursting pressures of the anastomoses were significantly higher in the PEEP group; however, the hydroxyproline content was significantly lower in the PEEP group than in the ZEEP group. At day 7, the PEEP group was significantly associated with increased neoangiogenesis compared with the ZEEP group. The anastomotic healing process is positively influenced by the intraoperative PEEP application.

Ovalbumin-induced lung disease in the pony: role of vagal mechanisms

1982 ◽  
Vol 53 (3) ◽  
pp. 719-725 ◽  
Author(s):  
F. J. Derksen ◽  
N. E. Robinson ◽  
R. F. Slocombe
Keyword(s):  
Respiratory System ◽  
Minute Ventilation ◽  
Left Lung ◽  
Arterial Oxygen Tension ◽  
Lung Compliance ◽  
Arterial Oxygen ◽  
Pulmonary Mechanics ◽  
Vagal Blockade ◽  
Before And After ◽  
Respiratory System Resistance

In awake sensitized ponies, we studied the effect of aerosol ovalbumin challenge on ventilation, pulmonary mechanics, lung volume, and gas exchange before and after vagal blockade. We also challenged the left lung and measured respiratory rate (f) and right and left respiratory system resistance (RrsR, RrsL) before and after both left and bilateral vagal section. Bilateral ovalbumin aerosol challenge increased f, minute ventilation (VE), total respiratory system resistance (Rrs), and minimal volume, decreased dynamic compliance, total lung capacity, and arterial oxygen tension, and was without effect on tidal volume (VT), functional residual capacity, quasi-static lung compliance, and arterial carbon dioxide tension. Vagal blockade reversed the increase in f, VE, and Rrs and increased VT. Challenge of the left lung increased f and RrsL but did not alter RrsR. Bilateral vagal section reversed the tachypnea but unilateral section did not. Histopathologic lesions included acute fibrinopurulent obstructive bronchiolitis, bronchitis, edema, and alveolar distension. We conclude that local mechanisms are of critical importance in the pathogenesis of ovalbumin-induced airway obstruction in ponies, that increased sensitivity of airway smooth muscle to normal vagal tone may also play a role, and that tachypnea following challenge is caused by activity of pulmonary receptors with vagal afferent fibers.

scholarly journals The Effect of Halothane-Nitrous Oxide Anaesthesia and Spontaneous Ventilation on Arterial Blood Oxygenation and Physiological Deadspace

1976 ◽  
Vol 4 (1) ◽  
pp. 41-45
Author(s):  
M. Morgan ◽  
J. Norman
Keyword(s):  
Nitrous Oxide ◽  
Oxygen Tension ◽  
Arterial Oxygen Tension ◽  
Volume Ratio ◽  
Carbon Dioxide Tension ◽  
Blood Oxygenation ◽  
Arterial Oxygen ◽  
Significant Deterioration ◽  
Arterial Blood ◽  
Oxide Anaesthesia

Arterial blood, inspired and expired gas samples were taken from seven patients anaesthetized with halothane (1–2 per cent) and nitrous oxide in oxygen and who breathed spontaneously. Over a two hour period, the average arterial oxygen tension was 75 mm Hg and carbon dioxide tension 49 mm Hg. No significant deterioration of either blood gas value occurred during the two hours. The dead-space/tidal volume ratio and alveolar-arterial oxygen tension difference did not alter significantly during the period of the study.

OXYGEN THERAPY IN THE NEWBORN INFANT

PEDIATRICS ◽  
1971 ◽  
Vol 47 (6) ◽  
pp. 1086-1087
Author(s):  
Jerold F. Lucey ◽  
Marvin Cornblath ◽  
Stanley N. Graven ◽  
Sheldon B. Korones ◽  
L. Stanley James ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Oxygen Tension ◽  
Newborn Infant ◽  
Newborn Infants ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Retrolental Fibroplasia ◽  
Arterial Blood ◽  
Increased Risk ◽  
Inspired Oxygen

The following recommendations will appear in the revision of the manual, Standards and Recommendations for Hospital Care of Newborn Infants, scheduled for publication early in 1971. Because the Committee felt a sense of urgency to provide these recommendations to pediatricians, family physicians, and other health professionals caring for newborn infants, they are being published prior to appearance of the manual. The statement has had extensive review by a large number of experts not on the Committee, and their comments and suggestions have been followed in the preparation of the final draft. It was also reviewed and approved by the Committee on Drugs of the Academy at their meeting in San Francisco October 24, 1970. When a newborn infant needs extra oxygen, it must be administered with great care because there is a causal relationship between a higher than normal oxygen tension in arterial blood (60 to 100 mm Hg) and retrolental fibroplasia (retinopathy of prematurity). When the normal O2 tension is exceeded, there is an increased risk of retrolental fibroplasia. The upper limit of arterial oxygen tension and its duration which are safe for these infants is not known. It is probable that even concentrations of 40% of inspired oxygen (formerly considered safe) could be dangerous for some infants. An inspired oxygen concentration of 40% may be insufficient for infants with cardiorespiratory disease to raise the oxygen tension of arterial blood to a normal level. In such instances, an inspired oxygen concentration of 60%, 80%, or higher may be necessary.

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