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1.

Objective

To determine agreement between invasive blood pressures measured in three peripheral arteries in anaesthetized horses undergoing elective surgery.

Study design

Prospective balanced incomplete block design.

Animals

A total of 18 client-owned horses.

Methods

Invasive blood pressure (IBP) was measured simultaneously in one of the following three combinations: 1) transverse facial and facial artery; 2) transverse facial and metatarsal artery; and 3) facial and metatarsal artery. The agreement in blood pressure measured for each combination was performed in six horses. At each sample time, systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were measured concurrently in each artery, and the mean of three consecutive measurements was recorded. The position of horse, heart rate and use of dobutamine were also recorded. Bland–Altman analysis was used to assess agreement between sites.

Results

A total of 54 paired measurements were obtained, with 18 paired measurements from each combination. All paired measurements showed poor and haphazard (nonsystematic) agreement. The widest limit of agreement was 51 mmHg for SAP measured in the facial artery and metatarsal artery, with a bias of –11 mmHg. The smallest limit of agreement was 16 mmHg for MAP measured in the transverse facial and metatarsal artery, with a bias of 1 mmHg.

Conclusions and clinical relevance

There was poor and haphazard agreement for SAP, MAP and DAP measured in each pair of peripheral arteries in this study. These results show that blood pressure measured in different peripheral arteries cannot be used interchangeably. This has implications for studies that use IBP as an outcome variable and studies determining agreement between noninvasive blood pressure and IBP measurements in horses under general anaesthesia.  相似文献   

2.

Objectives

1) To determine which peripheral artery commonly used for invasive arterial blood pressure (IBP) monitoring yields the least bias when compared with noninvasive blood pressure (NIBP) values obtained at the antebrachium of the dog, and 2) to identify and describe differences in systolic (SAP), mean (MAP) and diastolic arterial pressures (DAP) among different anatomical locations.

Study design

Prospective experimental study.

Animals

Twenty adult hound dogs weighing 24.5 ± 1.1 kg (mean ± standard deviation).

Methods

Four peripheral arteries—dorsal pedal, median caudal, intermediate auricular and superficial palmar arteries—were catheterized with 20 gauge, 3.8 cm catheters. One NIBP cuff was placed in the middle third of the antebrachium. Four sets of IBP and NIBP measurements were simultaneously collected every 2 minutes. A linear mixed model was performed to analyze the collected data.

Results

IBP values varied depending on the arterial catheterization site. The difference was greater for SAP. NIBP measured at the antebrachium had the best agreement with IBP measured at the median caudal artery.

Conclusion and clinical relevance

IBP varies among anatomical locations. The smallest bias and narrowest limits of agreement were obtained at the median caudal artery, providing the best overall agreement with the equipment studied. The median caudal artery may be the preferable anatomical location for clinical comparison studies between IBP and NIBP in dogs when the cuff is on the antebrachium.  相似文献   

3.

Objective

To assess agreement between noninvasive blood pressure (NIBP) oscillometrically-derived values from a multiparameter monitor (Datex Ohmeda S/5 Compact) with those obtained by invasive blood pressure (IBP) measurement in anaesthetised horses undergoing elective surgery.

Study design

Prospective clinical study.

Animals

A total of 40 healthy adult horses.

Methods

Horses were anaesthetised with various anaesthetic protocols (based on clinical requirements). Depending on positioning, cannulation of the facial or lateral metatarsal artery was performed for IBP measurement. The cannula was connected via a transducer to the monitor. An appropriately sized NIBP cuff was placed around the tail base and connected to the same monitor. Systolic (SAP), mean (MAP) and diastolic (DAP) arterial blood pressures were continuously recorded from the invasive system, and at 3 minute intervals from the oscillometric system, throughout the surgical procedure using a Datex iCollect program. An appropriate arithmetic correction factor was applied to the oscillometric results where the cuff was not level with the heart. Assessment of the degree of agreement between invasive and noninvasive readings at each time point was performed using a modified Bland-Altman analysis.

Results

While in many horses there was relatively close correlation between the values obtained over time, there was substantial variability in individual animals which resulted in wide Bland-Altman limits of agreement. The oscillometric device over-reads by approximately 32, 23 and 22 mmHg, and under-reads by 26, 17 and 19 mmHg for SAP, MAP and DAP, respectively, compared with the IBP values. However, using the mean difference and standard deviation, the device conforms to American College of Veterinary Internal Medicine (ACVIM) standards.

Conclusions and clinical relevance

Oscillometric blood pressure measurement using the Datex Ohmeda S/5 Compact multiparameter monitor conforms to ACVIM standards when the NIBP cuff is placed on the tail. However, because of the wide variability in measurements, we cannot recommend this technique to guide therapy in anaesthetised adult horses.  相似文献   

4.

Objective

To determine the accuracy of high-definition oscillometry (HDO) for arterial pressure measurement during injectable or inhalation anesthesia in horses.

Study design

Prospective, clinical study.

Animals

Twenty-four horses anesthetized for procedures requiring lateral recumbency.

Methods

Horses were premedicated with xylazine, and anesthesia induced with diazepam–ketamine. Anesthesia was maintained with xylazine–ketamine–guaifenesin combination [TripleDrip (TD; n = 12) or isoflurane (ISO; n = 12)]. HDO was used to obtain systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, and heart rate (HR) using an 8-cm-wide cuff around the proximal tail. Invasive blood pressure (IBP), SAP, MAP, DAP and HR were recorded during HDO cycling. Bland–Altman analysis for repeated measures was used to compare HDO and IBP for all measurements. The generalized additive model was used to determine if means in the differences between HDO and IBP were similar between anesthetic protocols for all measurements.

Results

There were >110 paired samples for each variable. There was no effect of anesthetic choice on HDO performance, but more variability was present in TD compared with ISO. Skewed data required log-transformation for statistical comparison. Using raw data and standard Bland–Altman analysis, HDO overestimated SAP (TD, 3.8 ± 28.3 mmHg; ISO, 3.5 ± 13.6 mmHg), MAP (TD, 4.0 ± 23.3 mmHg; ISO, 6.3 ± 10.0 mmHg) and DAP (TD, 4.0 ± 21.2 mmHg; ISO, 7.8 ± 13.6 mmHg). In TD, 26–40% HDO measurements were within 10 mmHg of IBP, compared with 60–74% in ISO. Differences between HDO and IBP for all measurements were similar between anesthetic protocols. The numerical difference between IBP and HDO measurements for SAP, MAP and DAP significantly decreased as cuff width:tail girth ratio increased toward 40%.

Conclusion and clinical relevance

More variability in HDO occurred during TD. The cuff width:tail girth ratio is important for accuracy of HDO.  相似文献   

5.

Objectives

To determine feasibility and repeatability of measuring the anatomic regurgitant orifice area (AROA) using real-time three-dimensional transthoracic echocardiography (RT3DE) in dogs with myxomatous mitral valve disease (MMVD), and to investigate differences in the AROA of dogs with different disease severity and in different American College of Veterinary Internal Medicine (ACVIM) stages.

Animals

Sixty privately-owned dogs diagnosed with MMVD.

Methods

The echocardiographic database of our institution was retrospectively searched for dogs diagnosed with MMVD and RT3DE data set acquisition. Dogs were classified into mild, moderate, or severe MMVD according to a Mitral Regurgitation Severity Score (MRSS), and into stage B1, B2 or C according to ACVIM staging. The RT3DE data sets were imported into dedicated software and a short axis plane crossing the regurgitant orifice was used to measure the AROA. Feasibility, inter- and intra-observer variability of measuring the AROA was calculated. Differences in the AROA between dogs in different MRSS and ACVIM stages were investigated.

Results

The AROA was measurable in 60 data sets of 81 selected to be included in the study (74%). The inter- and intra-observer coefficients of variation were 26% and 21%, respectively. The AROA was significantly greater in dogs with a severe MRSS compared with dogs with mild MRSS (p=0.045). There was no difference between the AROA of dogs in different ACVIM clinical stages.

Conclusions

Obtaining the AROA using RT3DE is feasible and might provide additional information to stratify mitral regurgitation severity in dogs with MMVD. Diagnostic and prognostic utility of the AROA deserves further investigation.  相似文献   

6.

Objectives

To provide reference intervals for 2-dimensional linear and area-based estimates of left atrial (LA) function in healthy dogs and to evaluate the ability of estimates of LA function to differentiate dogs with subclinical myxomatous mitral valve disease (MMVD) and similarly affected dogs with congestive heart failure (CHF).

Animals

Fifty-two healthy adult dogs, 88 dogs with MMVD of varying severity.

Methods

Linear and area measurements from 2-dimensional echocardiographs in both right parasternal long and short axis views optimized for the left atrium were used to derive estimates of LA active emptying fraction, passive emptying fraction, expansion index, and total fractional emptying. Differences for each estimate were compared between healthy and MMVD dogs (based on ACVIM classification), and between MMVD dogs with subclinical disease and CHF that had similar LA dimensions. Diagnostic utility at identifying CHF was examined for dogs with subclinical MMVD and CHF. Relationships with bodyweight were assessed.

Results

All estimates of LA function decreased with increasing ACVIM stage of mitral valve disease (p<0.05) and showed negative relationships with increasing LA size (all r2 values < 0.2), except for LA passive emptying fraction, which did not differ or correlate with LA size (p=0.4). However, no index of LA function identified CHF better than measurements of LA size. Total LA fractional emptying and expansion index showed modest negative correlations with bodyweight.

Conclusions

Estimates of LA function worsen with worsening MMVD but fail to discriminate dogs with CHF from those with subclinical MMVD any better than simple estimates of LA size.  相似文献   

7.

Objective

To compare intraocular pressure (IOP) and pupillary diameter (PD) following intravenous (IV) administration of dexmedetomidine and acepromazine in dogs.

Study design

Prospective, randomized experimental trial.

Animals

A group of 16 healthy adult dogs aged (mean ± standard deviation) 4.9 ± 3.3 years and weighing 15.7 ± 9.6 kg, without pre-existing ophthalmic disease.

Methods

IV dexmedetomidine hydrochloride (0.002 mg kg–1; DEX) or acepromazine maleate (0.015 mg kg–1; ACE) was administered randomly to 16 dogs (eight per group). The IOP and PD, measured using applanation tonometry and Schirmer's strips mm scale, respectively, and the heart rate (HR), systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures and respiratory rate (fR) were recorded at baseline, at time of injection, and then 5, 10, 15, 20 and 25 minutes after injection. A single ophthalmologist, unaware of treatment, performed all measurements under consistent light conditions. Values were compared with baseline and among treatments using a multivariate mixed-effects model (p ≤ 0.05).

Results

The IOP was significantly lower in the DEX group compared with the ACE group at 10 (p < 0.01) and 15 minutes (p < 0.01) after drug injection. PD was significantly smaller compared to baseline for the entire duration of the study (p < 0.01) in both groups. Dogs in the DEX group had significant lower HR (p < 0.01) and fR (p < 0.01), higher SAP (p < 0.01) and DAP (p < 0.01) at all time points, and higher MAP (p < 0.01) during the first 15 minutes following drug injection in comparison with the ACE group.

Conclusions and clinical relevance

Our results suggest that premedication with IV dexmedetomidine temporarily decreases IOP when compared with IV acepromazine. Both drugs cause miosis.  相似文献   

8.

Objective

To determine the agreement of invasive blood pressure measured in the facial, metatarsal and carotid arteries, and evaluate the effects of two haemodynamic conditions on agreement.

Study design

Prospective randomized study.

Animals

A group of eight horses aged 7 (4–23) years with a body weight of 493 ± 33 kg.

Methods

Horses were anaesthetized and positioned in dorsal recumbency. Invasive blood pressure was measured simultaneously via catheters placed in the facial, metatarsal and carotid arteries. Cardiovascular function and agreement between arteries was assessed before and during administration of phenylephrine and sodium nitroprusside. These were administered until carotid mean pressure (MAPc) increased or decreased from baseline (65 ± 5) to >90 or <50 mmHg, respectively. Data recorded at each sample time included systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures for carotid (c), facial (f) and metatarsal (m) arteries as well as cardiac output (Q˙t) and systemic vascular resistance (SVR). Bland–Altman analysis was used to assess agreement between peripheral and central sites, and regression analysis to determine influence of Q˙t and SVR.

Results

The largest difference was observed in SAPc and SAPm with a bias and limits of agreement (LOA) of 2 (?15 to 19) mmHg. The bias (LOA) for MAPc and MAPf was 2 (?4 to 9) mmHg and for MAPc and MAPm was 5 (?4 to 14) mmHg. The best agreement for DAP was seen between DAPc and DAPf with bias (LOA) of 1 (?3 to 5) mmHg. Regression analysis indicated marginal influence on agreement by Q˙t on MAPc and MAPf.

Conclusions and clinical relevance

MAP and DAP of the carotid artery were higher than those of the peripheral arteries, which may lead to overzealous treatment of hypotension, albeit maintaining central pressures. Q˙t and SVR did not largely influence the difference between sites.  相似文献   

9.

Objective

To compare the effects of intravenous (IV) medetomidine-morphine and medetomidine-methadone on preoperative sedation, isoflurane requirements and postoperative analgesia in dogs undergoing laparoscopic surgery.

Study design

Randomized, crossover trial.

Animals

Twelve adult Beagle dogs weighing 15.1 ± 4.1 kg.

Methods

Dogs were administered medetomidine (2.5 μg kg?1) IV 5 minutes before either methadone (MET) or morphine (MOR) (0.3 mg kg?1) IV. Anaesthesia was induced with propofol, maintained with isoflurane in oxygen, and depth was clinically assessed and adjusted by an anaesthetist blinded to the treatment. Animals underwent laparoscopic abdominal biopsies. Sedation and nausea scores, pulse rate (PR), respiratory rate (fR), noninvasive systolic arterial blood pressure (SAP), rectal temperature (RT) and pain scores were recorded before drug administration, 5 minutes after medetomidine injection and 10 minutes after opioid administration. Propofol dose, PR, fR, SAP, oesophageal temperature (TOES), end-tidal carbon dioxide and end-tidal isoflurane concentration (Fe′Iso) were recorded intraoperatively. Pain scores, PR, fR, SAP and RT were recorded 10 minutes after extubation, every hour for 6 hours, then at 8, 18 and 24 hours. The experiment was repeated with the other drug 1 month later.

Results

Nine dogs completed the study. After opioid administration and intraoperatively, PR, but not SAP, was significantly lower in MET. Fe′Iso was significantly lower in MET. Temperature decreased in both treatments. Pain scores were significantly higher in MOR at 3 hours after extubation, but not at other time points. Two dogs required rescue analgesia; one with both treatments and one in MOR.

Conclusion and clinical relevance

At the dose used, sedation produced by both drugs when combined with medetomidine was equivalent, while volatile anaesthetic requirements and PR perioperatively were lower with methadone. Postoperative analgesia was deemed to be adequate for laparoscopy with either protocol, although methadone provided better analgesia 3 hours after surgery.  相似文献   

10.

Objective

To compare the effect of propofol and alfaxalone on laryngeal motion under a light plane of anaesthesia in nonbrachycephalic and brachycephalic dogs anaesthetized for nonemergency procedures.

Study design

Prospective, randomized clinical trial.

Animals

A total of 48 client-owned dogs (24 nonbrachycephalic and 24 brachycephalic).

Methods

A standardized premedication of methadone (0.2 mg kg?1) and acepromazine (0.01 mg kg?1) was administered intramuscularly. Dogs were randomly assigned to be induced with increments of propofol (1–4 mg kg?1) or alfaxalone (0.5–2 mg kg?1). Laryngeal assessment was performed under a light plane of anaesthesia by a surgeon (GTH) who was unaware of the induction protocol. Laryngeal movement was assessed as either being present when abduction of the laryngeal cartilages upon inspiration was identified, or absent when abduction was not recognized. Simultaneously, a 60-second video was recorded. The same surgeon (GTH) and an additional surgeon (NK) re-evaluated the videos 1 month later. Categorical comparisons were studied using Chi square and Fisher’s exact test where appropriate. Pairwise evaluation of agreement between scorers was undertaken with the kappa statistic (κ).

Results

There were no significant differences (p > 0.05) identified between the presence or absence of laryngeal motion between dogs administered propofol or alfaxalone, as well as when analysing nonbrachycephalic and brachycephalic dogs separately. The majority of dogs (>75%) maintained some degree of laryngeal motion with both protocols. Agreement between assessors was excellent (κ = 0.822).

Conclusions

Alfaxalone maintained laryngeal motion similarly to propofol in nonbrachycephalic and brachycephalic dogs.

Clinical relevance

Both agents would appear appropriate for allowing assessment of laryngeal motion in nonbrachycephalic and brachycephalic dogs. The assessment technique of subjective evaluation of laryngeal motion via peroral laryngoscopy under a light plane of anaesthesia produced consistent results amongst assessors, regardless of the induction agent used.  相似文献   

11.

Objective

To characterize the cardiopulmonary characteristics of two different anaesthetic protocols (tiletamine/zolazepam ± medetomidine) and their suitability for the immobilization of healthy chimpanzees undergoing cardiac assessment.

Study design

Prospective, clinical, longitudinal study.

Animals

Six chimpanzees (Pan troglodytes) aged 4–16 years weighing 19.5–78.5 kg were anaesthetized on two occasions.

Methods

Anaesthesia was induced with tiletamine/zolazepam (TZ) (3–4 mg kg–1) or tiletamine/zolazepam (2 mg kg–1) and medetomidine (0.02 mg kg–1) (TZM) via blow dart [intramuscular (IM)] and maintained with intermittent boluses of ketamine (IV) or zolazepam/tiletamine (IM) as required. The overall quality of the anaesthesia was quantified based on scores given for: quality of induction, degree of muscle relaxation and ease of intubation. The time to achieve a light plane of anaesthesia, number of supplemental boluses needed and recovery characteristics were also recorded. Chimpanzees were continuously monitored and heart rate (HR), pulse rate (PR), respiratory rate (fR) oxygen saturation of haemoglobin (SpO2), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), rectal temperature, mucous membrane colour and capillary refill time recorded. During the first procedure (TZ) animals underwent a 12-channel electrocardiogram (ECG), haematology, biochemistry and cardiac biomarker assessment to rule out the presence of pre-existing cardiovascular disease. A detailed echocardiographic examination was carried out by the same blinded observer during both procedures. Data were compared using Student’s paired t-test or Wilcoxon rank tests as appropriate.

Results

There was a significant difference for the area under the curves between anaesthetic protocols for HR, SAP, MAP and fR. No significant differences in the echocardiographic measurements were evident. Quality of anaesthesia was significantly better with TZM and no additional boluses were required. The TZ protocol required multiple supplemental boluses.

Conclusions and clinical relevance

Both combinations are suitable for immobilization and cardiovascular evaluation of healthy chimpanzees. Further work is required to evaluate the effect of medetomidine in cardiovascular disease.  相似文献   

12.

Objectives

Goal-directed fluid therapy (GDFT) based on pulse pressure variation (PPV) was used in anaesthetized dogs undergoing abdominal surgeries. The aims were 1) to evaluate the success rate of the PPV ≥13% in detecting fluid responsiveness [delta stroke volume (ΔSV) ≥10%]; 2) to assess the correlation between PPV, systolic pressure variation (SPV), Plethysmograph Variability Index (PVI) and central venous pressure (CVP) and 3) to establish the threshold value for the PVI that would predict a PPV value of ≥13% and indirectly discriminate responders from nonresponders to fluid therapy.

Study design

Clinical, prospective, interventional study.

Animals

A total of 63 client-owned dogs scheduled for abdominal procedures.

Methods

PPV and SPV were calculated manually from the invasive blood pressure trace on the Datex monitor. PVI was recorded from the Masimo pulse oximeter. Fluid challenge (10 mL kg?1 Compound Sodium Lactate) was performed when PPV was ≥13% and/or mean arterial pressure (MAP) < 60 mmHg. Fluid responsiveness was assessed by the transoesophageal Doppler probe. Cardiovascular parameters (heart rate, MAP, PPV, SPV, PVI, SV and if available, CVP) were measured before and after each fluid intervention.

Results

PPV ≥ 13% reliably predicted fluid responsiveness in 82.9% of cases. There was positive correlation between PPV and SPV (r = 0.84%), PPV and logPVI (r = 0.46) as well as SPV and logPVI (r = 0.45). Noninvasive PVI value ≥13% should predict PPV threshold value (13%) with 97% sensitivity and 68% specificity. There was no statistically significant correlation between PPV and CVP.

Conclusions

PPV is a useful clinical tool to detect occult hypovolaemia and predict cardiovascular response to fluid challenge. Use of PPV is recommended as a part of GDFT in dogs undergoing abdominal procedures.  相似文献   

13.

Objective

To investigate whether pulse pressure variation (PPV) can predict fluid responsiveness in healthy dogs during clinical surgery.

Study design

Prospective clinical study.

Animals

Thirty-three isoflurane-anesthetized dogs with arterial hypotension during orthopedic surgery.

Methods

Fluid challenge with lactated Ringer's solution (15 mL kg?1 in 15 minutes) was administered in mechanically ventilated dogs (tidal volume 10 mL kg?1) with hypotension [mean arterial pressure (MAP) < 65 mmHg]. The volume expansion was considered effective if cardiac output (CO; transesophageal Doppler) increased by ≥ 15%. Cardiopulmonary data were analyzed using two-way ANOVA, receiver operating characteristics (ROC) curves and Spearman coefficient; p < 0.05 was considered significant.

Results

Effective volume expansion, mean ± standard deviation 42 ± 4% increase in CO (p < 0.0001) was observed in 76% of the dogs, resulting in a decrease in PPV (p < 0.0001) and increase in MAP (p < 0.0001), central venous pressure (CVP; p = 0.02) and ejection fraction (p < 0.0001) compared with before the fluid challenge. None of these changes occurred when volume expansion resulted in a nonsignificant CO increase of 4 ± 5%. No significant differences were observed in blood gas analysis between responsive and nonresponsive dogs. The increase in CO was correlated with the decrease in PPV (r = ?0.65; p < 0.0001) but absolute values of CO and PPV were not correlated. The PPV performance (ROC curve area: 0.89 ± 0.06, p = 0.0011) was better than that of CVP (ROC curve area: 0.54 ± 0.12) and MAP (ROC curve area: 0.59 ± 0.13) to predict fluid responsiveness. The best cut-off for PPV to distinguish responders and nonresponders was 15% (50% sensitivity and 96% specificity).

Conclusions and clinical relevance

In mechanically ventilated, healthy, isoflurane-anesthetized dogs, PPV predicted fluid responsiveness to volume expansion, and MAP and CVP did not show such applicability.  相似文献   

14.

Objective

To evaluate the ability of pulse wave transit time (PWTT) to detect changes in stroke volume (SV) and to estimate cardiac output (CO) compared with the thermodilution technique in isoflurane-anaesthetized dogs.

Study design

Prospective, experimental study.

Animals

Eight adult laboratory dogs.

Methods

The dogs were anaesthetized with isoflurane and mechanically ventilated. Reference CO (TDCO) was measured via a pulmonary artery catheter using the thermodilution technique and reference SV (TDSV) was calculated. PWTT was calculated as the time from the electrocardiogram R-wave peak to the rise point of the pulse oximeter wave. Estimated CO (esCO) was derived from PWTT after calibration with arterial pulse pressure (both non-invasive and invasive methods) and TDCO. Haemodynamic changes were induced by administration of phenylephrine (vasoconstriction), high isoflurane (vasodilatation and negative inotropy) and dobutamine (vasodilatation and positive inotropy). Trending between percentage change in PWTT and TDSV was assessed using concordance analysis and receiver operator characteristic (ROC) curve. The agreement between esCO and TDCO was evaluated using the Bland–Altman method.

Results

The direction of percentage change between consecutive PWTT and the corresponding TDSV showed a concordance rate of 95%, with correlation coefficients of ?0.86 (p < 0.001). Area under the ROC curve for the change in PWTT to detect 15% change in TDSV was 0.91 (p < 0.001). TDCO compared with esCO calibrated with invasive and non-invasive blood pressure showed a bias (precision of agreement) of 0.58 (1.54) and 0.57 (1.59) L minute?1 with a percentage error of ±61% and ±63%, respectively.

Conclusions and clinical relevance

In isoflurane-anaesthetized dogs, PWTT showed a good trending ability to detect 15% changes in SV. This technique is easy to use, inexpensive, non-invasive and could become routine anaesthetic monitoring. However, the agreement between absolute esCO and TDCO was unacceptable.  相似文献   

15.

Introduction

Assessing left atrial (LA) size is an integral part of the cardiac evaluation in dogs. Left atrial size is routinely evaluated by thoracic radiographs or echocardiography.

Objectives

The objectives of the study were to assess agreement of subjective radiographic left atrial enlargement (LAE) between readers, to compare subjective radiographic LAE with echocardiography, and to assess the accuracy and reliability of commonly used Roentgen signs for LAE.

Animals

One hundred one dogs with thoracic radiographs and echocardiography performed on the same day at a veterinary teaching hospital were retrospectively reviewed.

Methods

Thoracic radiographs were reviewed by two cardiologists, two radiologists, and two small animal rotating interns. Radiographs were evaluated for the subjective presence and severity of LAE and for seven Roentgen signs. Echocardiographic LA size was evaluated objectively by the left atrial-to-aortic root ratio and LA volume indexed to body weight. Interreader agreement of radiographic LAE evaluation and agreement between radiographic LAE assessment and echocardiographic LAE were assessed by linearly weighted kappa and intraclass correlation coefficient.

Results

Interreader agreement for the presence and degree of radiographic LAE ranged from moderate to substantial. The agreement between subjective radiographic LAE and echocardiographic LAE was moderate. Single Roentgen signs had poor to fair correlation with echocardiographic LAE.

Conclusions

The present study found that interreader agreement for radiographic classification of LAE was substantial among specialists and moderate for all readers. Subjective, global assessment of radiographic LAE is better than using any single Roentgen sign.  相似文献   

16.

Objective

To investigate the dose-dependent effects of isoflurane and dobutamine on haemodynamics in dogs with experimentally induced mitral valve insufficiency (MI).

Study design

Experimental, dose–response study.

Animals

Six healthy Beagle dogs.

Methods

Dogs with surgically induced MI were anaesthetized once. First, anaesthesia was maintained at an end-tidal isoflurane concentration (Fe′Iso) 1.0% (ISO1.0) for 20 minutes. Then, dobutamine was infused successively at 2, 4, 8 and 12 μg kg?1 minute?1 (DOB2–12) for 10 minutes at each dose rate. Measurements were recorded at each stage. Dobutamine was discontinued and Fe′Iso was increased to 1.5% (ISO1.5) for 20 minutes. Dobutamine was administered similarly to ISO1.0, and cardiovascular variables were recorded. The same sequence was repeated for Fe′Iso 2.0% (ISO2.0). Aortic pressure (AoP) and left atrial pressure (LAP) were recorded by radiotelemetry. The combination method of the pressure–volume loop analysis and transoesophageal echocardiography was used to measure cardiovascular variables: end-systolic elastance (Ees), effective arterial elastance (Ea), Ea/Ees, forward stroke volume (FSV), heart rate (HR), and cardiac output (CO).

Results

High isoflurane concentration resulted in reduced Ees and increased Ea/Ees, which indicated low arterial pressure. High-dose dobutamine administration resulted in increased Ees and FSV at all isoflurane concentrations. In ISO1.5 and ISO2.0, HR was lower at DOB4 than baseline (BL) but increased at DOB12 compared with DOB4. CO increased at ≥ DOB8 compared with BL. In ISO1.5 and ISO2.0, systolic and mean AoP increased at ≥ DOB4 and ≥ DOB8, respectively. LAP did not change under all conditions.

Conclusions and clinical relevance

The dose-dependent hypotensive effect of isoflurane in MI dogs was mainly derived from the decrease in contractility. Dobutamine increased AoP without increasing LAP by increasing the contractility attenuated by isoflurane. Our findings may improve the cardiovascular management of dogs with MI undergoing general anaesthesia with isoflurane.  相似文献   

17.

Objective

To compare two methods of Bohr–Enghoff physiological dead space to tidal volume ratio (Vd/VtBohr–Enghoff) determination using a mixing chamber and an E-CAiOVX metabolic monitor.

Study design

Prospective, clinical, method-comparison study.

Animals

Twenty horses anaesthetized for elective orthopaedic procedures.

Methods

Horses were anaesthetized with isoflurane in oxygen and the lungs were mechanically ventilated (Vt 15 ± 2 mL kg?1). Arterial blood was sampled to provide arterial partial pressure of carbon dioxide (PaCO2) for dead space calculation using a metabolic monitor. Mixed expired partial pressure of carbon dioxide (PēCO2) obtained from the custom-made mixing chamber was recorded at the time of arterial blood sampling. Dead space fraction was calculated using the Enghoff modification of the Bohr equation. Agreement between the methods was assessed by Bland–Altman test. A clinically acceptable error was defined to be ≤ 10%.

Results

Forty-nine simultaneous Vd/VtBohr–Enghoff results were obtained. There was no clinically significant bias between the mixing chamber and E-CAiOVX. The limits of agreement were within a priori defined error (bias ± 95% limits of agreement: ?0.022 ± 0.078).

Conclusions and clinical relevance

Acceptable agreement was found between the two methods. The E-CAiOVX metabolic monitor might be a suitable device for measuring Vd/VtBohr–Enghoff in anaesthetized horses.  相似文献   

18.

Objective

To evaluate endotracheal tube intracuff pressure (Pcuff) changes over time and the effect of these changes on air leak pressure (Pleak).

Study design

Prospective experimental study.

Animals

A group of nine healthy adult Beagle dogs.

Methods

In part I, in vitro measurements of Pcuff were recorded for 1 hour in eight endotracheal tubes subjected to four treatments: room temperature without lubricant (RT0L), room temperature with lubricant (RTWL), body temperature without lubricant (BT0L), and body temperature with lubricant (BTWL). In part II, nine dogs were endotracheally intubated and Pleak was evaluated at Pcuff of 25 mmHg. Subsequently, Pcuff was reset to 25 mmHg (baseline) and Pcuff measurements were recorded every 5 minutes for 1 hour. Subsequently, a second Pleak measurement was recorded at the current Pcuff. The data were analyzed using Wilcoxon signed-rank test, repeated measures anova and Mann–Whitney U test.

Results

In part I, Pcuff differed significantly between the RT0L and RTWL treatments at 5–60 minutes, and between the BT0L and BTWL treatments at 5–35, 55 and 60 minutes (p < 0.05). In part II, compared with baseline pressures, mean Pcuff decreased to <18 mmHg at 10 minutes and significant decreases were recorded at 15–60 minutes (Pcuff range: 10.0 ± 4.9 to 13.4 ± 6.3 mmHg, mean ± standard deviation). Significant differences were observed between the first and second Pleak measurements (p = 0.034). Pleak decreased in six of nine dogs, was not changed in two dogs and increased in one dog.

Conclusions and clinical relevance

Significant decreases in Pcuff over time were measured. Pleak may decrease during anesthesia and increase the risk for silent pulmonary aspiration. The results indicate the need for testing Pcuff more than once, especially at 10 minutes after the onset of anesthesia.  相似文献   

19.

Objective

The aim of this study was to evaluate the effect of continuous positive airway pressure (CPAP) on regional distribution of ventilation and dead space in anaesthetized horses.

Study design

Randomized, experimental, crossover study.

Animals

A total of eight healthy adult horses.

Methods

Horses were anaesthetized twice with isoflurane in 50% oxygen and medetomidine as continuous infusion in dorsal recumbency, and administered in random order either CPAP (8 cmH2O) or NO CPAP for 3 hours. Electrical impedance tomography (and volumetric capnography (VCap) measurements were performed every 30 minutes. Lung regions with little ventilation [dependent silent spaces (DSSs) and nondependent silent spaces (NSSs)], centre of ventilation (CoV) and dead space variables, as well as venous admixture were calculated. Statistical analysis was performed using multivariate analysis of variance and Pearson correlation.

Results

Data from six horses were statistically analysed. In CPAP, the CoV shifted to dependent parts of the lungs (p < 0.001) and DSSs were significantly smaller (p < 0.001), while no difference was seen in NSSs. Venous admixture was significantly correlated with DSS with the treatment time taken as covariate (p < 0.0001; r = 0.65). No differences were found for any VCap parameters.

Conclusions and clinical relevance

In dorsally recumbent anaesthetized horses, CPAP of 8 cmH2O results in redistribution of ventilation towards the dependent lung regions, thereby improving ventilation-perfusion matching. This improvement was not associated with an increase in dead space indicative for a lack in distension of the airways or impairment of alveolar perfusion.  相似文献   

20.

Objectives

The objective is to describe the clinical, radiographic, echocardiographic and angiographic findings in dogs with systemic-to-pulmonary arteriovenous fistula (SPAVF).

Animals

Thirteen medical records of client-owned dogs with a diagnosis of SPAVF were reviewed/analysed.

Methods

This is a retrospective study of case records. Thoracic radiography, transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), three-dimensional TEE, intracardiac echocardiography, fluoroscopy-guided or computed tomography (CT) angiography were carried out.

Results

Based on the TTE, SPAVF was identified in seven of the included dogs. In eight cases, TEE and angiography were both performed and confirmed the diagnosis. Computed tomography angiography was performed in three dogs. A case was diagnosed by TEE alone, another one by three-dimensional TEE and the latter by intracardiac echocardiography.

Conclusions

Transthoracic echocardiography identified seven cases of SPAVF, while definitive diagnosis in the remaining dogs required selective angiography or computed tomography angiography.  相似文献   

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