Motor effects of fentanyl in isoflurane-anaesthetized pigs and the subsequent effect of ketanserin or naloxone.

OBJECTIVE: To examine the effect of ketanserin and naloxone on fentanyl-induced motor activity in isoflurane-anaesthetized pigs. STUDY DESIGN: Randomized, blinded, prospective two-group study. ANIMALS: A group of 12 crossbred pigs weighing 22-31 kg. METHODS: Fentanyl was administered to isoflurane-anaesthetized pigs at 7.5 µg kg-1 hour-1 for 40 minutes intravenously, followed by an intravenous injection of naloxone 0.1 mg kg-1 or ketanserin 1 mg kg-1. Electromyography (EMG) and accelerometry were used to record motor unit activity and tremors, respectively. To test the effect of drug administration on motor activity, data from a 5 minute period at baseline, immediately before and after antagonist injection were compared in a mixed model; p < 0.05. RESULTS: Results are reported with the median difference, 95% confidence intervals and corresponding p-values in brackets. Fentanyl significantly increased EMG activity [30.51 (1.84-81.02) µV, p = 0.004] and induced tremors [0.09 (0.02-0.18) m s-2, p < 0.001] in 10 of 12 pigs. Ketanserin significantly reduced EMG [32.22 (6.29-136.80) µV, p = 0.001] and tremor [0.10 (0.03-0.15) m s-2, p = 0.007] activity. No significant effect was found for naloxone on EMG [26.76 (-13.28-91.17) µV, p = 0.4] or tremors [0.08 (-0.01-0.19) m s-2, p = 0.08]. CONCLUSIONS AND CLINICAL RELEVANCE: Fentanyl can induce motor activity in anaesthetized pigs, with a suggested link to the serotonergic system. This study shows that ketanserin can antagonize this activity, which supports the role of serotonin. This knowledge contributes to the general understanding of the motor effects of fentanyl and especially the problem of tremors in anaesthetized pigs.

Use of admission serum neutrophil gelatinase-associated lipocalin (NGAL) concentrations as a marker of sepsis and outcome in neonatal foals.

BACKGROUND: Equine neonatal sepsis can be challenging to diagnose and prognosticate. Neutrophil gelatinase-associated lipocalin (NGAL), a new marker of renal damage and inflammation, can potentially be helpful. OBJECTIVES: To evaluate NGAL in neonatal foals with sepsis, and assess its relation to outcome. ANIMALS: Foals ≤ 14 days, with admission blood analysis and stored serum. METHODS: NGAL was measured on stored serum from 91 foals. Foals were scored for sepsis and survival and categorized according to sepsis status (septic, sick non-septic, healthy, and uncertain sepsis status) and outcome groups (survivors and non-survivors). The septic foals were further sub-categorized according to severity (normal sepsis, severe sepsis and septic shock). A Kruskal-Wallis test was used to compare serum NGAL concentrations in survivors and non-survivors, in the sepsis status groups, and in the sepsis severity groups. Optimal cut-off values for serum NGAL concentrations to diagnose sepsis and outcome were determined with receiver operating characteristic (ROC) curves. NGAL was compared to creatinine and SAA. RESULTS: Median serum NGAL concentrations were significantly higher in septic than non-septic foals. However, serum NGAL concentrations did not differ between sepsis severity subgroups. Serum NGAL concentrations were significantly lower in survivors than in non-survivors. Optimal cut-off values of serum NGAL concentrations were 455 µg/L (sensitivity 71.4%, specificity 100%) and 1104 µg/L (sensitivity 39.3%, specificity 95.2%) for predicting sepsis and non-survival, respectively. NGAL correlated to SAA, but not to creatinine. NGAL performed similarly to SAA to diagnose sepsis. CONCLUSION: Serum NGAL concentrations may be useful for diagnosing sepsis and predicting outcome.

Cardiovascular effects of intravenous morphine in anesthetized horse.

Objectives: To investigate whether morphine causes a change in mean arterial blood pressure (MAP) heart rate (HR) and oxygen extraction (OE) rate in healthy horses anesthetized with isoflurane and a dexmedetomidine infusion. Material and methods: The study design was prospective clinical, randomized, blinded two groups including 33 horses. All horses were sedated with romifidine IV, and anesthesia was induced with midazolam IV and ketamine IV and maintained with isoflurane in oxygen and medical air and a dexmedetomidine infusion. As a baseline venous and arterial blood, HR and MAP were sampled. Thereafter either morphine 0.1 mg kg-1 IV or an equivalent volume of NaCl 0.9% IV was administered. HR and MAP were then further sampled for 5 min before venous and arterial blood was again sampled. OE was calculated based upon arterial and venous blood gas analysis. To evaluate the change in minimum MAP, mean HR, and OE, the differences between baseline and observation period values were further termed delta MAP, delta HR, and delta OE. Individual delta MAPs were normalized to the minimum baseline value and are reported as a percentage. Alpha was set to 0.05. Confidence intervals 95% (CI) were calculated for delta MAP, delta HR, and delta OE within groups, and for the difference between groups. Results: The 95% CIs for delta MAP (%), delta HR (min-1), and delta OE (mL/dL) in the morphine group were -20.5 to -9.0, 0.6 to 3.1, and -0.1 to 0.6 and in the placebo group were -17.4 to -10.1, 0.2 to 2.0, and -0.2 to 0.3, respectively. The 95% CI for the differences in delta MAP (%), delta HR (min-1), and delta OE (mL/dL) were -5.5 to 7.6, -2.3 to 0.7, and -0.7 to 0.2, respectively. The minimum MAP of one horse in the morphine group decreased around 50% between baseline and observation period with almost unchanged OE and HR. Conclusion and clinical relevance: The effects of morphine 0.1 mg kg-1 IV on HR, MAP, and OE in healthy horses anesthetized with isoflurane and a CRI of dexmedetomidine are minimal.

Serum amyloid A as a marker to detect sepsis and predict outcome in hospitalized neonatal foals.

BACKGROUND: Serum amyloid A (SAA) has been reported to hold promise as diagnostic and prognostic marker in foals. This has not been investigated thoroughly. OBJECTIVES: Evaluate admission SAA concentrations as predictor of sepsis and outcome. ANIMALS: Five hundred and ninety hospitalized foals <14 days old. METHODS: Retrospective multicenter study. Foals were scored with sepsis and survival scores, grouped according to health category (septic, sick but nonseptic, uncertain sepsis status) and outcome; septic foals were further categorized according to severity (normal sepsis, severe sepsis, and septic shock). SAA was compared between groups using Mann-Whitney test and Kruskal-Wallis test. Receiver operating characteristic curves identified optimal SAA cut off values for detecting sepsis and predicting outcome. RESULTS: Admission SAA concentrations differed significantly between sick nonseptic foals (312.1 ± 685.4 mg/L) and septic foals (1079.7 ± 1254.5 mg/L) and increased with increasing sepsis score. SAA did not differ between sepsis severity groups. The optimal cut off for sepsis detection was 1050 mg/L (sensitivity 30.2%, specificity 90.7%). Admission SAA concentrations were lower in surviving (435.0 ± 723.6 mg/L) compared to nonsurviving foals (1062.7 ± 1440.1 mg/L) and decreased with increasing survival score. The optimal cut off for nonsurvival prediction was 1250 mg/L (sensitivity 22.1%, specificity 90.8%). CONCLUSIONS AND CLINICAL IMPORTANCE: SAA concentration was higher in septic foals and nonsurviving foals. Even though optimal cut offs for SAA to detect sepsis and predict outcome had low sensitivity, they had good specificity. SAA can therefore be used as a marker to rule out sepsis and nonsurvival.

Lidocaine spray 10% prior to intravenous catheterisation in dogs.

A common and to some degree painful procedure in veterinary practice is to insert an intra-venous catheter. In both human and veterinary medicine, a topical mixture of lidocaine and prilocaine (EMLA cream) has shown to reduce the pain, however a period of 60 min between application and initiation of the procedure is recommended. This time lapse is not always suitable for clinical practise and a shorter time before anaesthetic effect is therefore desirable. Lidocaine has a shorter time lapse (1-3 min) when used on mucus membrane; however, the effect of lidocaine for desensitization of skin has shown variable results in humans. The aim of the study was to evaluate the effect of topical lidocaine spray 10% on the response to placement of venous catheters in dogs. Topical lidocaine spray 10% or NaCl 0.9% was administered prior to placing an intravenous catheter in the cephalic vein. A cross-over of treatment with 2 h wash out period was used before placing a catheter in the opposite cephalic vein. The procedure was video recorded and the dogs' responses were later scored by three persons blinded to treatment using a visual analogue scale. The VAS scores were normalised and the mean difference between treatments were compared using Wilcox signed-rank test. This study could not find a statistical difference between the treatments (P = 0.1763) and could conclude that no significant difference in response to intravenous catheterisation was found between application of NaCl 0.9% or lidocaine 10% prior to the procedure.

Evaluation of the foal survival score in a Danish-Swedish population of neonatal foals upon hospital admission.

BACKGROUND: It is highly desirable to assess the probability of survival in sick neonatal foals upon admission. The foal survival score (FSS) is a published scoring system used to estimate the probability of survival in hospitalized neonatal foals <4 days old. HYPOTHESIS/OBJECTIVES: To evaluate the ability of the FSS to predict survival in older foals from a geographically different area compared to the original study. ANIMALS: Five-hundred ninety hospitalized neonatal foals ≤14 days of age. METHODS: Retrospective Danish-Swedish multicenter study that included details of signalment, history, clinical examination, laboratory results, necropsy findings, and outcome. Scores and score variables were compared between survivors and nonsurvivors using logistic regression. The optimal cutoff and its test parameters were calculated using a receiver operator characteristic curve. RESULTS: Prematurity, cold extremities, ≥2 infectious or inflammatory sites, blood glucose concentration, and total white blood cell counts were significantly associated with nonsurvival (P ≤ .02). The optimal cutoff to predict survival was ≥6, resulting in sensitivity 78%, specificity 58%, 92% positive predictive value, and 31% negative predictive value. The test performed equally well in foals <4 days old compared to those 4-14 days old. CONCLUSIONS AND CLINICAL IMPORTANCE: Using the suggested optimal cutoff of ≥6, the FSS performed moderately well and may aid in early determination of prognosis for survival. However, the FSS did perform differently in another population and therefore should be assessed under local conditions so that its diagnostic potential is not overestimated.