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1.
ObjectiveTo evaluate agreement between end-tidal carbon dioxide (Pe′CO2) and PaCO2 with sidestream and mainstream capnometers in mechanically ventilated anesthetized rabbits, with two ventilatory strategies.Study designProspective experimental study.AnimalsA total of 10 New Zealand White rabbits weighing 3.6 ± 0.3 kg (mean ± standard deviation).MethodsRabbits anesthetized with sevoflurane were intubated with an uncuffed endotracheal tube (3.0 mm internal diameter) and adequate seal. For Pe′CO2, the sidestream capnometer sampling adapter or the mainstream capnometer was placed between the endotracheal tube and Bain breathing system (1.5 L minute–1 oxygen). PaCO2 was obtained from arterial blood collected every 5 minutes. A time-cycled ventilator delivered an inspiratory time of 1 second and 12 or 20 breaths minute–1. Peak inspiratory pressure was initially set to achieve Pe′CO2 normocapnia of 35–45 mmHg (4.6–6.0 kPa). A total of five paired Pe′CO2 and PaCO2 measurements were obtained with each ventilation mode for each capnometer. Anesthetic episodes were separated by 7 days. Agreement was assessed using Bland-Altman analysis and linear mixed models; p < 0.05.ResultsThere were 90 and 83 pairs for the mainstream and sidestream capnometers, respectively. The mainstream capnometer underestimated PaCO2 by 12.6 ± 2.9 mmHg (proportional bias 0.44 ± 0.06 mmHg per 1 mmHg PaCO2 increase). With the sidestream capnometer, ventilation mode had a significant effect on Pe′CO2. At 12 breaths minute–1, Pe′CO2 underestimated PaCO2 by 23.9 ± 8.2 mmHg (proportional bias: 0.81 ± 0.18 mmHg per 1 mmHg PaCO2 increase). At 20 breaths minute–1, Pe′CO2 underestimated PaCO2 by 38.8 ± 5.0 mmHg (proportional bias 1.13 ± 0.10 mmHg per 1 mmHg PaCO2 increase).Conclusions and clinical relevanceBoth capnometers underestimated PaCO2. The sidestream capnometer underestimated PaCO2 more than the mainstream capnometer, and was affected by ventilation mode.  相似文献   

2.
ObjectiveTo test whether partial pressure of CO2 in expired gas (PēCO2) predicts the partial pressure of CO2 in arterial blood (PaCO2) in apneic chickens during air sac insufflation anesthesia at three different ventilation states. Secondary objective: To determine the PēCO2 at which apnea occurs during air sac insufflation anesthesia.Study designRandomized cross-over study.AnimalsTwenty-three healthy male white leghorn chickens.MethodsChickens were anesthetized via mask with isoflurane in oxygen and an air sac cannula was placed in the right abdominal air sac. Delivery of isoflurane in O2 was transferred from the mask to the air sac cannula. The birds were maintained at a surgical plane of anesthesia and apnea was induced by adjusting gas flow; the PēCO2 at apnea was recorded. The birds were then paralyzed and gas flow was adjusted to achieve three different PēCO2s in random order: 43 mmHg (5.6 kPa) [hypoventilation]; 33 mmHg (4.3 kPa) [normoventilation]; and 23 mmHg (3.0 kPa) [hyperventilation]. After maintaining the target expired isoflurane concentration (EIso; 1.85 or 1.90%) and PēCO2 for 15 minutes, arterial blood gas analysis was performed to determine the PaCO2. The chickens were euthanized at the end of the experiment.ResultsBased on Bland-Altman comparisons, PēCO2 was not strongly associated with PaCO2 during the three ventilation states. The PēCO2 at which apnea occurred varied {median (minimum, maximum): 35 (30, 48) mmHg [4.6 (3.9, 6.2) kPa]}.ConclusionsMeasured PēCO2 cannot be used in a simple linear fashion to predict PaCO2 in birds during air sac insufflation anesthesia. The PēCO2 at which apnea occurs during air sac insufflation anesthesia is not predictable.Clinical relevanceArterial blood gases should be used to monitor CO2 during air sac insufflation anesthesia to verify appropriate patient ventilation.  相似文献   

3.
ObjectiveTo characterize the impact of mechanical positive pressure ventilation on heart rate (HR), arterial blood pressure, blood gases, lactate, glucose, sodium, potassium and calcium concentrations in rattlesnakes during anesthesia and the subsequent recovery period.Study designProspective, randomized trial.AnimalsTwenty one fasted adult South American rattlesnakes (Crotalus durissus terrificus).MethodsSnakes were anesthetized with propofol (15 mg kg−1) intravenously, endotracheally intubated and assigned to one of four ventilation regimens: Spontaneous ventilation, or mechanical ventilation at a tidal volume of 30 mL kg−1 at 1 breath every 90 seconds, 5 breaths minute−1, or 15 breaths minute−1. Arterial blood was collected from indwelling catheters at 30, 40, and 60 minutes and 2, 6, and 24 hours following induction of anesthesia and analyzed for pH, PaO2, PaCO2, and selected variables. Mean arterial blood pressure (MAP) and HR were recorded at 30, 40, 60 minutes and 24 hours.ResultsSpontaneous ventilation and 1 breath every 90 seconds resulted in a mild hypercapnia (PaCO2 22.4 ± 4.3 mmHg [3.0 ± 0.6 kPa] and 24.5 ± 1.6 mmHg [3.3 ± 0.2 kPa], respectively), 5 breaths minute−1 resulted in normocapnia (14.2 ± 2.7 mmHg [1.9 ± 0.4 kPa]), while 15 breaths minute−1 caused marked hypocapnia (8.2 ± 2.5 mmHg [1.1 ± 0.3 kPa]). Following recovery, blood gases of the four groups were similar from 2 hours. Anesthesia, independent of ventilation was associated with significantly elevated glucose, lactate and potassium concentrations compared to values at 24 hours (p < 0.0001). MAP increased significantly with increasing ventilation frequency (p < 0.001). HR did not vary among regimens.Conclusions and clinical relevanceMechanical ventilation had a profound impact on blood gases and blood pressure. The results support the use of mechanical ventilation with a frequency of 1–2 breaths minute−1 at a tidal volume of 30 mL kg−1 during anesthesia in fasted snakes.  相似文献   

4.
ObjectiveTo determine changes in distribution of lung ventilation with increasing intra-abdominal pressure (IAP) from carbon dioxide (CO2) insufflation in standing sedated horses.Study designProspective experimental study.AnimalsA group of six healthy adult horses.MethodsEach horse was sedated with acepromazine, detomidine and butorphanol and sedation maintained with a detomidine infusion. The horse was restrained in a stocks system and a 32 electrode electrical impedance tomography (EIT) belt was wrapped around the thorax at the fifth–sixth intercostal space. EIT images and arterial blood samples for PaO2 and PaCO2, pH and lactate concentration were obtained during capnoperitoneum at 0 (baseline A), 5, 8 and 12 mmHg as IAP increased and at 8, 5, 0 (baseline B) mmHg as IAP decreased. At each IAP, after a 2 minute stabilization period, EIT images were recorded for ≥ 2 minutes to obtain five consecutive breaths. Statistical analysis was performed using anova for repeated measures with Geisser-Greenhouse correction and a Tukey’s multiple comparison test for parametric data. The relationship between PaO2 and the center of ventilation in the ventral-dorsal (CoV-VD) and right-left (CoV-RL) directions or total impedance change as a surrogate for tidal volume (ΔZVT) were tested using linear regression analysis. Significance was assumed when p ≤ 0.05.ResultsThere were no significant changes in CoV-VD, CoV-RL, PaO2, PaCO2, lactate concentration, pH, heart rate and respiratory rate with targeted IAP. There was a significant decrease in ΔZVT compared with baseline A at 5 mmHg IAP as IAP was increased.Conclusions and clinical relevanceCapnoperitoneum causes a significant decrease in ΔZVT in standing sedated horses with increasing IAP.  相似文献   

5.
ObjectiveHypoxemia is common during equine field anesthesia. Our hypothesis was that oxygen therapy from a portable oxygen concentrator would increase PaO2 during field anesthesia compared with the breathing of ambient air.Study designProspective clinical study.AnimalsFifteen yearling (250 – 400 kg) horses during field castration.MethodsHorses were maintained in dorsal recumbency during anesthesia with an intravenous infusion of 2000 mg ketamine and 500 mg xylazine in 1 L of 5% guaifenesin. Arterial samples for blood gas analysis were collected immediately post-induction (PI), and at 15 and 30 minutes PI. The control group (n = 6) breathed ambient air. The treatment group (n = 9) were administered pulsed-flow oxygen (192 mL per bolus) by nasal insufflation during inspiration for 15 minutes PI, then breathed ambient air. The study was performed at 1300 m above sea level. One-way and two-way repeated-measures anova with post-hoc Bonferroni tests were used for within and between-group comparisons, respectively. Significance was set at p ≤ 0.05.ResultsMean ± SD PaO2 in controls at 0, 15 and 30 minutes PI were 46 ± 7 mmHg (6.1 ± 0.9 kPa), 42 ± 9 mmHg (5.6 ± 1.1 kPa), and 48 ± 7 mmHg (6.4 ± 0.1 kPa), respectively (p = 0.4). In treatment animals, oxygen administration significantly increased PaO2 at 15 minutes PI to 60 ± 13 mmHg (8.0 ± 1.7 kPa), compared with baseline values of 46 ± 8 mmHg (6.1 ± 1 kPa) (p = 0.007), and 30 minute PI values of 48 ± 7 mmHg (6.5 ± 0.9 kPa) (p = 0.003).ConclusionsThese data show that a pulsed-flow delivery of oxygen can increase PaO2 in dorsally recumbent horses during field anesthesia with ketamine-xylazine-guaifenesin.Clinical relevanceThe portable oxygen concentrator may help combat hypoxemia during field anesthesia in horses.  相似文献   

6.
ObjectiveTo compare PaO2 and PaCO2 in horses recovering from general anesthesia maintained with either apneustic anesthesia ventilation (AAV) or conventional mechanical ventilation (CMV).Study designRandomized, crossover design.AnimalsA total of 10 healthy adult horses from a university-owned herd.MethodsDorsally recumbent horses were anesthetized with isoflurane in oxygen [inspired oxygen fraction = 0.3 initially, with subsequent titration to maintain PaO2 ≥ 85 mmHg (11.3 kPa)] and ventilated with AAV or CMV according to predefined criteria [10 mL kg–1 tidal volume, PaCO2 40–45 mmHg (5.3–6.0 kPa) during CMV and < 60 mmHg (8.0 kPa) during AAV]. Horses were weaned from ventilation using a predefined protocol and transferred to a stall for unassisted recovery. Arterial blood samples were collected and analyzed at predefined time points. Tracheal oxygen insufflation at 15 L minute–1 was provided if PaO2 < 60 mmHg (8.0 kPa) on any analysis. Time to oxygen insufflation, first movement, sternal recumbency and standing were recorded. Data were analyzed using repeated measures anova, paired t tests and Fisher’s exact test with significance defined as p < 0.05.ResultsData from 10 horses were analyzed. Between modes, PaO2 was significantly higher immediately after weaning from ventilation and lower at sternal recumbency for AAV than for CMV. No PaCO2 differences were noted between ventilation modes. All horses ventilated with CMV required supplemental oxygen, whereas three horses ventilated with AAV did not. Time to first movement was shorter with AAV. Time to oxygen insufflation was not different between ventilation modes.ConclusionsAlthough horses ventilated with AAV entered the recovery period with higher PaO2, this advantage was not sustained during recovery. Whereas fewer horses required supplemental oxygen after AAV, the use of AAV does not preclude the need for routine supplemental oxygen administration in horses recovering from general anesthesia.  相似文献   

7.
ObjectiveTo assess the effects of two sizes of silicone endotracheal tubes with internal diameter 26 mm (ETT26) and 30 mm (ETT30) inflated to minimum occlusive volume on tracheal and laryngeal mucosa of adult horses anesthetized for 2 hours with isoflurane.Study designProspective, randomized, blinded, crossover experimental study.AnimalsA total of eight healthy adult mares.MethodsUpper airway endoscopy and ultrasound measurements of internal tracheal diameter were performed the day before anesthesia. Horses were anesthetized and orotracheally intubated with ETT26 or ETT30. Ease of intubation was scored. The cuff was inflated in 10 mL increments to produce a seal. Final volume of air used and intracuff (IC) pressure (measured by pressure transducer) were recorded. At the end of anesthesia, a manometer was used to measure IC pressure and these measurements compared against measurements from the pressure transducer. Laryngeal and tracheal mucosa were assessed via endoscopy and assigned a score 0–3 before anesthesia, and at 2 and 24 hours following extubation.ResultsData are from seven horses because one horse with laryngeal hemiplegia was excluded. Mean tracheal ultrasound measurement was 3.5 ± 0.4 cm. No significant differences were noted between endotracheal tube sizes for intubation score, IC pressures, inflation volumes or tracheal or laryngeal injury scores at any time point. IC pressure measured by manometer was slightly higher than that by transducer (+1.0 ± 2.8 mmHg).Conclusions and clinical relevanceResults identified no clear advantage of one endotracheal tube size over the other in the population of horses studied, when endotracheal intubation is properly applied and IC pressure is carefully monitored. However, given that ETT26 was associated with the highest observed IC pressures and the only observed incidents of tracheal circumferential erythema, the larger ETT30 may be the better choice in most cases where tracheal size is sufficient.  相似文献   

8.
ObjectiveTo evaluate agreement with PaCO2 of two low sampling rate sidestream capnometers and a mainstream capnometer in rabbits and the effect of using high fresh gas flow from a Bain coaxial breathing system.Study designProspective, crossover study.AnimalsA total of 10 New Zealand White rabbits weighing 3.4 ± 0.3 kg [mean ± standard deviation (SD)].MethodsTwo sidestream analyzers (Viamed VM-2500-S and Capnostream 35) with a sampling rate of 50 mL minute–1 and a mainstream capnometer (Capnostat 5) were tested. All capnometers used infrared spectroscopy and advanced microprocessor technology. Rabbits were anesthetized and intubated with noncuffed endotracheal tubes of 3 mm internal diameter and adequate seal. A sidestream sampling adapter or the mainstream capnometer was attached to the endotracheal tube and connected to a Bain coaxial breathing system. Oxygen (1.5 L minute–1) delivered sevoflurane to maintain anesthesia. An auricular artery catheter allowed blood sampling for PaCO2 analysis corrected to rectal temperature. Inspired and end-tidal carbon dioxide (Pe′CO2) measurements were recorded during blood sample withdrawal. From each rabbit, 10 paired PaCO2/Pe′CO2 measurements were obtained. Each rabbit was recovered from anesthesia and was anesthetized again with an alternate capnometer after 1 week. Data were analyzed using Bland–Altman and two-way anova for repeated measures.ResultsAnalysis included 100 paired samples. Negative bias reflects underestimation of PaCO2. Bland–Altman mean (±1.95 SD) was –16.7 (–35.2 to 1.8) mmHg for Capnostat 5, –27.9 (–48.6 to –7.2) mmHg for Viamed, and –18.1 (–34.3 to –1.9) mmHg for Capnostream. Viamed PaCO2–Pe′CO2 gradient was greater than other two capnometers.ConclusionsAll three capnometers underestimated PaCO2. Capnostat 5 and Capnostream performed similarly.Clinical relevanceThese capnometers underestimated PaCO2 in spontaneously breathing rabbits anesthetized using a Bain coaxial breathing system with high fresh gas flows.  相似文献   

9.

Objective

To record the cardiopulmonary effects of pleural CO2 positive pressure insufflation in anesthetized horses.

Study design

Prospective study.

Animals

Seven horses (mean ± standard deviation, 530.9 ± 68.1 kg) undergoing terminal surgery.

Methods

Horses were sedated with xylazine. Anesthesia was induced with ketamine–propofol and maintained with isoflurane, positive pressure ventilation, detomidine infusion, and butorphanol with the horses in dorsal recumbency. Baseline measurements were cardiac output, heart rate, pulmonary and systemic arterial and right atrial blood pressures, body temperature, expired and inspired gas concentrations, and arterial and mixed venous blood gases, electrolytes, glucose, and lactate concentrations. An 18 gauge 6.6 cm needle was inserted into the right pleural cavity midway between the sternum and dorsal midline in the sixth or seventh intercostal space for pleural pressure (PP) measurement. A 14 gauge 18 cm needle placed 5 cm below the previous needle allowed CO2 insufflation into the pleural cavity. All measurements were repeated after: needle insertion, at 2, 5, and 8 mmHg PPs, and after pleural gas removal (GR). Data were compared with baseline using one-way analysis of variance with repeated measures. p < 0.05 was considered significant.

Results

Actual PPs were within 1.1 mmHg of the targeted PP. Pulmonary systolic and mean arterial pressures, alveolar dead space to tidal volume ratio, and isoflurane requirements increased at 8 mmHg PP and GR. Cardiac index decreased at 5 mmHg PP. Stroke index decreased at 2 mmHg PP to GR. PaO2 decreased at 5 mmHg PP to GR. PaCO2 increased at 8 mmHg PP and GR. Oxygen delivery decreased at 5 and 8 mmHg PP. Intrapulmonary shunt fraction and lactate concentration increased with GR.

Conclusions and clinical relevance:

Severe adverse cardiopulmonary effects arise from CO2 positive pressure insufflation into the right hemithorax in dorsally recumbent isoflurane-anesthetized horses. PP should be ≤2 mmHg.  相似文献   

10.
At present there is no alternative to the use of a demand valve and pressurised oxygen for emergency ventilation in large animal field anaesthesia, therefore we aimed at providing a proof‐of‐principle of a small (2.5 l) commercial foot pump to provide emergency intermittent positive pressure ventilation (IPPV) in large animals. The study was performed during elective field anaesthesia for castration of 5 Haflinger stallions. Horses were premedicated with acepromazine i.m. after catheterisation of the jugular vein, further sedation was obtained with detomidine and butorphanol i.v. Anaesthesia was induced with ketamine and midazolam i.v. and maintained with a constant rate infusion of midazolam, ketamine and xylazine. After endotracheal intubation the foot pump, modified with a manually operated expiratory valve, was connected to the endotracheal tube and oxygen (6 l/min) was supplied. Anaesthesia was monitored using spirometry, respiratory gas analysis, pulse oximetry and arterial blood gas analysis. When arterial partial pressure of carbon dioxide (PaCO2) exceeded 6.65 kPa, IPPV was provided by 2–4 consecutive compressions of the pump aiming at a tidal volume of 10 ml/kg bwt. The PaCO2 was maintained at 6.18 ± 3.06 kPa (mean ± s.d.) with a respiratory rate of 4–10 breaths/min. The tidal volume was 2678–8300 ml with a peak inspiratory pressure of 24 ± 6.6 cmH2O and a mean minute volume of 68.5 ± 13 l/min. Inspired oxygen concentration ranged from 26–46% (36 ± 7%) and arterial partial pressure of oxygen from 8.38–11.03 kPa (10.1 ± 0.93 kPa). The modified foot pump enables the practitioner to provide IPPV to large animals in emergency situations.  相似文献   

11.
ObjectiveTo determine if pressure support ventilation (PSV) weaning from general anesthesia affects ventilation or oxygenation in horses.Study designProspective randomized clinical study.AnimalsTwenty client‐owned healthy horses aged 5 ± 2 years, weighing 456 ± 90 kg.MethodsIn the control group (CG; n = 10) weaning was performed by a gradual decrease in respiratory rate (fR) and in the PSV group (PSVG; n = 10) by a gradual decrease in fR with PSV. The effect of weaning was considered suboptimal if PaCO2 > 50 mmHg, arterial pH < 7.35 plus PaCO2 > 50 mmHg or PaO2 < 60 mmHg were observed at any time after disconnection from the ventilator until 30 minutes after the horse stood. Threshold values for each index were established and the predictive power of these values was tested.ResultsPressure support ventilation group (PSVG) had (mean ± SD) pH 7.36 ± 0.02 and PaCO2 41 ± 3 mmHg at weaning and the average lowest PaO2 69 ± 6 mmHg was observed 15 minutes post weaning. The CG had pH 7.32 ± 0.02 and PaCO2 57 ± 6 mmHg at weaning and the average lowest PaO2 48 ± 5 mmHg at 15 minutes post weaning. No accuracy in predicting weaning effect was observed for fR (p = 0.3474), minute volume (p = 0.1153), SaO2 (p = 0.1737) and PaO2/PAO2 (p = 0.1529). A high accuracy in predicting an optimal effect of weaning was observed for VT > 10 L (p = 0.0001), fR/VT ratio ≤ 0.60 breaths minute?1 L?1 (p = 0.0001), VT/bodyweight > 18.5 mL kg?1 (p = 0.0001) and PaO2/FiO2 > 298 (p = 0.0002) at weaning. A high accuracy in predicting a suboptimal effect of weaning was observed for VT < 10 L (p = 0.0001), fR/VT ratio ≥ 0.60 breaths minute?1 L?1 (p = 0.0001) and Pe′CO2 ≥ 38 mmHg (p = 0.0001) at weaning.Conclusions and clinical relevancePressure support ventilation (PSV) weaning had a better respiratory outcome. A higher VT, VT/body weight, PaO2/FiO2 ratio and a lower fR/VT ratio and Pe′CO2 were accurate in predicting the effect of weaning in healthy horses recovering from general anesthesia.  相似文献   

12.
ObjectiveTo describe the anesthetic and adverse effects of an injectable anesthetic protocol in dogs as part of a high-volume sterilization program under field conditions in Belize.Study designProspective, observational, field study.AnimalsA total of 23 female and eight male dogs (14.2 ± 7.7 kg; age ≥ 8 weeks).MethodsUsing a volume per kg-based dose chart, dogs were administered ketamine (4.5 mg kg−1), medetomidine (0.04 mg kg−1) and hydromorphone (0.09 mg kg−1) intramuscularly. After induction of anesthesia, an endotracheal tube was inserted and dogs were allowed spontaneous breathing in room air. Monitoring included peripheral oxygen saturation (SpO2), mean arterial pressure (MAP), heart rate (HR), respiratory rate, rectal temperature and end-tidal carbon dioxide (Pe′CO2). Meloxicam (0.2 mg kg−1) was administered subcutaneously after surgery. Data were analyzed with linear models and chi-square tests (p < 0.05).ResultsOnset of lateral recumbency (3.4 ± 2 minutes) was rapid. Desaturation (SpO2 < 90%) was observed at least once in 64.5% of dogs and was more frequent in large dogs (p = 0.019). Hypercapnia (Pe′CO2 ≥ 50 mmHg; 6.7 kPa) was observed in 48.4% of dogs. MAP was 111 ± 19 mmHg, mean ± standard deviation. Hypertension (MAP ≥ 120 mmHg), bradycardia (HR ≤ 60 beats minute−1) and tachycardia (HR ≥ 140 beats minute−1) were observed in 45.2%, 16.1% and 3.3% of dogs, respectively. Hypotension and hypothermia were not observed. Sex was not significantly associated with any complication. Return of swallowing reflex and time to standing were 71 ± 23 and 152 ± 50 minutes after injection, respectively. Return of swallowing was significantly longer in large dogs.Conclusions and clinical relevanceAt the doses used, ketamine–medetomidine–hydromorphone was effective in dogs for high-volume sterilization. In this field setting, adverse effects included hypoventilation, hypoxemia and prolonged recovery.  相似文献   

13.
ObjectiveTo evaluate the effects of medetomidine, midazolam and ketamine (MMK) in captive gorillas after premedication with oral zuclopenthixol.Study designCase series.AnimalsSix gorillas, two males and four females, aged 9–52 years and weighing 63–155 kg.MethodsThe gorillas were given zuclopenthixol dihydrochloride 0.2 ± 0.05 mg kg?1 per os twice daily for 3 days for premedication. On the day of anaesthesia the dose of zuclopenthixol was increased to 0.27 mg kg?1 and given once early in the morning. Anaesthesia was induced with medetomidine 0.04 ± 0.004 mg kg?1, midazolam 0.048 ± 0.003 mg kg?1 and ketamine 4.9 ± 0.4 mg kg?1 intramuscularly (IM). Upon recumbency, the trachea was intubated and anaesthesia was maintained on 1–2% isoflurane in oxygen. Physiological parameters were monitored every 10 minutes and arterial blood gas analysis was performed once 30–50 minutes after initial darting. At the end of the procedure, 42–115 minutes after initial darting, immobilisation was antagonized with atipamezole 0.21 ± 0.03 mg kg?1 and sarmazenil 5 ± 0.4 μg kg?1 IM.ResultsRecumbency was reached within 10 minutes in five out of six animals. One animal required two additional darts before intubation was feasible. Heart rate ranged from 60 to 85 beats minute?1, respiratory rate from 17 to 46 breaths minute?1 and temperature from 36.9 to 38.3 °C. No spontaneous recoveries were observed and anaesthetic level was stable. Blood gas analyses revealed mild respiratory acidosis, and mean PaO2 was 24.87 ± 17.16 kPa (187 ± 129 mmHg) with all values being above 13.4 kPa (101 mmHg). Recovery was smooth and gorillas were sitting within 25 minutes.Conclusion and clinical relevanceThe drug combination proved to be effective in anaesthetizing captive gorillas of various ages and both sexes, with minimal cardio-respiratory changes.  相似文献   

14.
ObjectiveTo compare the effects of propofol and alfaxalone on respiration in cats.Study designRandomized, ‘blinded’, prospective clinical trial.AnimalsTwenty cats undergoing ovariohysterectomy.MethodsAfter premedication with medetomidine 0.01 mg kg−1 intramuscularly and meloxicam 0.3 mg kg−1 subcutaneously, the cats were assigned randomly into two groups: group A (n = 10) were administered alfaxalone 5 mg kg−1 minute−1 followed by 10 mg kg−1 hour−1 intravenously (IV) and group P (n = 10) were administered propofol 6 mg kg−1 minute−1 followed by 12 mg kg−1hour−1 IV for induction and maintenance of anaesthesia, respectively. After endotracheal intubation, the tube was connected to a non-rebreathing system delivering 100% oxygen. The anaesthetic maintenance drug rate was adjusted (± 0.5 mg kg−1 hour−1) every 5 minutes according to a scoring sheet based on physiologic variables and clinical signs. If apnoea > 30 seconds, end-tidal carbon dioxide (Pe′CO2) > 7.3 kPa (55 mmHg) or arterial haemoglobin oxygen saturation (SpO2) < 90% occurred, manual ventilation was provided. Methadone was administered postoperatively. Data were analyzed using independent-samples t-tests, Fisher's exact test, linear mixed-effects models and binomial test.ResultsManual ventilation was required in two and eight of the cats in group A and P, respectively (p = 0.02). Two cats in both groups showed apnoea. Pe′CO2 > 7.3 kPa was recorded in zero versus four and SpO2 < 90% in zero versus six cats in groups A and P respectively. Induction and maintenance dose rates (mean ± SD) were 11.6 ± 0.3 mg kg−1 and 10.7 ± 0.8 mg kg−1 hour−1 for alfaxalone and 11.7 ± 2.7 mg kg−1 and 12.4 ± 0.5 mg kg−1 hour−1 for propofol.Conclusion and clinical relevanceAlfaxalone had less adverse influence on respiration than propofol in cats premedicated with medetomidine. Alfaxalone might be better than propofol for induction and maintenance of anaesthesia when artificial ventilation cannot be provided.  相似文献   

15.
ObjectiveTo compare the effect of propofol, alfaxalone and ketamine on intraocular pressure (IOP) in cats.Study designProspective, masked, randomized clinical trial.AnimalsA total of 43 ophthalmologically normal cats scheduled to undergo general anesthesia for various procedures.MethodsFollowing baseline IOP measurements using applanation tonometry, anesthesia was induced with propofol (n = 15), alfaxalone (n = 14) or ketamine (n = 14) administered intravenously to effect. Then, midazolam (0.3 mg kg?1) was administered intravenously and endotracheal intubation was performed without application of topical anesthesia. The IOP was measured following each intervention. Data was analyzed using one-way anova and repeated-measures mixed design with post hoc analysis. A p-value <0.05 was considered significant.ResultsMean ± standard error IOP at baseline was not different among groups (propofol, 18 ± 0.6; alfaxalone, 18 ± 0.7; ketamine, 17 ± 0.5 mmHg). Following induction of anesthesia, IOP increased significantly compared with baseline in the propofol (20 ± 0.7 mmHg), but not in the alfaxalone (19 ± 0.8 mmHg) or ketamine (16 ± 0.7 mmHg) groups. Midazolam administration resulted in significant decrease from the previous measurement in the alfaxalone group (16 ± 0.7 mmHg), but not in the propofol group (19 ± 0.7 mmHg) or the ketamine (16 ± 0.8 mmHg) group. A further decrease was measured after intubation in the alfaxalone group (15 ± 0.9 mmHg).Conclusions and clinical relevancePropofol should be used with caution in cats predisposed to perforation or glaucoma, as any increase in IOP should be avoided.  相似文献   

16.
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17.
ObjectiveTo evaluate the fresh gas flow (FGF) rate requirements for the Humphrey ADE semi-closed breathing system in the Mapleson A mode; to determine the FGF at which rebreathing occurs, and compare the efficiency of this system to the Bain (Mapleson D) system in spontaneously breathing cats and small dogs.Study DesignProspective clinical study.AnimalsTwenty-five healthy (ASA score I or II) client-owned cats and dogs (mean ± SD age 4.7 ± 5.0 years, and body weight 5.64 ± 3.26 kg) undergoing elective surgery or minor procedures.MethodsAnaesthesia was maintained with isoflurane delivered via the Humphrey ADE system in the A mode using an oxygen FGF of 100 mL kg−1 minute−1. The FGF was then reduced incrementally by 5–10 mL kg−1minute−1 at approximately five-minute intervals, until rebreathing (inspired CO2 >5 mmHg (0.7 kPa)) was observed, after which flow rates were increased. In six animals, once the minimum FGF at which rebreathing occurred was found, the breathing system was changed to the Bain, and the effects of this FGF delivery examined, before FGF was increased.ResultsRebreathing did not occur at the FGF recommended by the manufacturer for the ADE. The mean ± SD FGF that resulted in rebreathing was 60 ± 20 mL kg−1minute−1. The mean minimum FGF at which rebreathing did not occur with the ADE was 87 ± 39 mL kg−1minute−1. This FGF resulted in significant rebreathing (inspired CO2 8.8 ± 2.6 mmHg (1.2 ± 0.3 kPa)) on the Bain system.ConclusionsThe FGF rates recommended for the Humphrey ADE are adequate to prevent rebreathing in spontaneously breathing cats and dogs <15 kg.Clinical relevanceThe Humphrey ADE system used in the A mode is a more efficient alternative to the Bain system, for maintenance of gaseous anaesthesia in spontaneously breathing cats and small dogs.  相似文献   

18.
Objective To evaluate the endotracheal tube cuff pressure achieved by four different inflation methods. Study design Prospective clinical study. Animals Eighty client owned dogs. Methods After anaesthesia induction, endotracheal intubation was performed using plastic or silicone tubes. A clinician unaware of tube type inflated the cuff by simple digital palpation (method A), thereafter the cuff was deflated and inflated again by a second clinician who tried to reproduce a previously learned cuff pressure of between 19 and 24 mmHg (method B). During method C the cuff was inflated to the minimum occlusive volume at an airway pressure of 20 cm H2O, and in method D the cuff was incrementally deflated until an audible air leak could be heard from the oral cavity at an airway pressure of 25 cm H2O. For all the methods, an operator recorded the actual cuff pressure obtained using a manometer. Heart rate, respiratory rate and mean arterial pressure were monitored throughout the procedure. Results The mean inflation pressure for plastic tubes was 56 ± 28 mmHg for method A, 20 ± 9 mmHg for method B, 35 ± 32 mmHg for method C and 46 ± 39 mmHg for method D. Pressures using silicone tubes were significantly higher than for plastic tubes, the mean registered pressures being 79 ± 39, 33 ± 16, 77 ± 50 and 92 ± 56 mmHg for methods A, B, C and D. Conclusions and Clinical Relevance None of the methods evaluated in this study can be considered effective for inflating the endotracheal tube cuff to within the optimal range when using silicone tubes. Direct measurement of the cuff pressure with a manometer is therefore recommended.  相似文献   

19.
ObjectiveTo evaluate the oxygen reserve index (ORI) as a noninvasive estimate of the PaO2 during moderate hyperoxaemia [100–200 mmHg (13.3–26.6 kPa)], and to determine ORI values identifying PaO2 > 100, > 150 (20.0 kPa) and > 200 mmHg in anaesthetized donkeys with an inspired fraction of oxygen (FiO2) > 0.95.Study designProspective observational study.AnimalsA group of 28 adult standard donkeys aged (mean ± standard deviation) 4 ± 2 years and weighing 135 ± 15 kg.MethodsDonkeys were sedated intramuscularly with xylazine and butorphanol; anaesthesia was induced with ketamine and diazepam and maintained with isoflurane in oxygen. An adhesive sensor probe was applied to the donkey’s tongue and connected to a Masimo pulse co-oximeter to determine ORI values. An arterial catheter was inserted into an auricular artery. After ORI signal stabilization, the value was noted and PaO2 determined by blood gas analysis. The Pearson correlation coefficient was used to assess the relationship between ORI and PaO2 for oxygen tension < 200 mmHg (< 26.6 kPa). The Youden index was used to identify the value of ORI that detected PaO2 > 150 and 200 mmHg (20.0 and 26.6 kPa) with the highest sensitivity and specificity.ResultsA total of 106 paired measurements were collected. A mild positive correlation was observed between ORI and PaO2 for values < 200 mmHg (26.6 kPa; r = 0.52). An ORI > 0.0, > 0.1 and > 0.3 indicated a PaO2 > 100, > 150 and > 200 mmHg (13.3, 20.0 and 26.6 kPa) with negative predictive values > 94%.Conclusions and clinical relevanceORI may provide a noninvasive indication of PaO2 > 100, > 150 and > 200 mmHg (13.3, 20.0 and 26.6 kPa) in anaesthetized donkeys with an FiO2 > 0.95, although it does not replace blood gas analysis for assessment of oxygenation.  相似文献   

20.
Objective The study aimed to investigate the effect of varying pulse lengths of inhaled nitric oxide (iNO), and 2.5 hours of continuous pulse‐delivered iNO on pulmonary gas exchange in anaesthetized horses. Study Design Experimental study. Animals Six Standardbred horses. Methods Horses received acepromazine, detomidine, guaifenesin, thiopentone and isoflurane in oxygen, were positioned in dorsal recumbency and were breathing spontaneously. iNO was on average pulsed during the first 20, 30, 43 or 73% of the inspiration in 15 minute steps. The pulse length that corresponded to the highest (peak) partial pressure of arterial oxygen (PaO2) in the individual horses was determined and delivered for a further 1.5 hours. Data measured or calculated included arterial and mixed venous partial pressures of O2 and CO2, heart rate, respiratory rate, expired minute ventilation, pulmonary and systemic arterial mean pressures, cardiac output and venous admixture. Data (mean ± SD) was analysed using anova with p < 0.05 considered significant. Results Although the pulse length of iNO that corresponded to peak PaO2 varied between horses, administration of all pulse lengths of iNO increased PaO2 compared to baseline. The shortest pulse lengths that resulted in the peak PaO2 were 30 and 43% of the inspiration. Administration of iNO increased PaO2 (12.6 ± 4.1 kPa [95 ± 31 mmHg] at baseline to a range of 23.0 ± 8.4 to 25.3 ± 9.0 kPa [173 to 190 mmHg]) and PaCO2 (8.5 ± 1.2 kPa [64 ± 9 mmHg] to 9.8 ± 1.5 kPa [73 ± 11 mmHg]) and decreased venous admixture from 32 ± 6% to 25 ± 6%. The increase in PaO2 and decrease in venous admixture was sustained for the entire 2.5 hours of iNO delivery. Conclusions The improvement in arterial oxygenation during pulsed delivery of iNO was significant and sustained throughout 2.5 hours of anaesthesia. Clinical relevance Pulsed iNO potentially could be used clinically to counteract hypoxemia in anaesthetized horses.  相似文献   

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