Ultrasound-guided quadratus lumborum block with 0.5 mL of 0.2% bupivacaine/kg is a valuable perioperative analgesic adjunct for cats undergoing ovariectomy.

OBJECTIVE: To assess the perioperative analgesic effects of bilateral ultrasound (US)-guided quadratus lumborum block (QLB) using low-volume (LV) or high-volume (HV) bupivacaine, compared to a control group, in cats undergoing ovariectomy. ANIMALS: 48 healthy female cats. METHODS: Cats were sedated with IM dexmedetomidine (5 µg/kg), ketamine (1 mg/kg), and methadone (0.2 mg/kg) followed by IV propofol induction and isoflurane maintenance. Cats were randomly assigned to 3 groups of 16 patients each: QLB-LV group (0.3 mL/kg/side), QLB-HV group (0.5 mL/kg/side), and control group (no QLB). Bilateral, in-plane, US-guided QLB was performed with lateral approach at the L2 transverse process with bupivacaine 0.2%. Physiological variables were recorded intraoperatively by a masked investigator. If intraoperative nociception occurred, fentanyl (1 µg/kg) was administered IV. Rescue postoperative analgesia (buprenorphine, 0.2 mg/kg) was administered in case of a Feline Grimace Scale score ≥ 4 after a 4-hour evaluation period. RESULTS: In the control group, heart rate (HR) was higher than the QLB-LV group during the first ovarian manipulation (P < .001) and higher than the QLB-HV group during both ovarian manipulations (P < .001 and P = .006). The need for intraoperative rescue analgesia and postoperative pain scores were significantly higher in the QLB-LV (P = .005 and P = .047) and control (P < .001 and P < .001) groups compared to the QLB-HV group. Buprenorphine was administered once in the control group. No clinical signs of bupivacaine toxicity or QLB complications were observed. CLINICAL RELEVANCE: Bilateral US-guided QLB-HV may effectively provide perioperative analgesia in feline patients undergoing ovariectomy.

Functional lateralization in social-emotional processing: The influence of sexual orientation and gender identity on cradling preferences.

The left-cradling bias (i.e., the motor asymmetry for cradling infants on the left side) has often been associated to the right-hemispheric social-emotional specialization, and it has often been reported to be stronger in females than in males. In this study we explored the effects of sexual orientation and gender identity on this lateral bias by means of a web-based investigation in a sample of adults (485 biological females and 196 biological males) recruited through LGBTQIA+ networks and general university forums. We exploited a cradling imagery task to assess participants' cradling-side preference, and standardized questionnaires to assess participants' homosexuality (Klein Sexual Orientation Grid) and gender nonconformity (Gender Identity/Gender Dysphoria Questionnaire for Adults and Adolescents). Results confirmed the expected left-cradling bias across all sexual orientation groups except for heterosexual males. Importantly, higher homosexuality scores were associated with higher proportions of left cradling in males. These results suggest that sexual orientation can influence cradling preference in males, indicating a complex interaction between biological and psychological factors in the laterality of social-emotional processing. Finally, the left-cradling bias seems to confirm its role as a behavioral proxy of social-emotional functional lateralization in humans.

Age-related differences on temporal source memory by using dynamic stimuli: the effects of POV and emotional valence.

Previous studies have highlighted that temporal source memory can be influenced by factors such as the individual's age and the emotional valence of the event to be remembered. In this study, we investigated how the different points of view (POVs) from which an event is presented could interact with the relationship between age-related differences and emotional valence on temporal source memory. One hundred and forty-one younger adults (aged 18-30) and 90 older adults (aged 65-74) were presented with a series of emotional videos shot from different POVs (first vs. third-person) in three sessions. In the fourth session, participants were asked to indicate in which session (1, 2, or 3) they viewed each video. The results indicated that the first-person POV amplified the effects of the emotional valence on temporal source memory. Only in this experimental condition, older adults "pushed away" negative stimuli by perceiving them as more distant in time, and "kept closer" positive stimuli by perceiving them as more recent. In comparison, younger adults "kept closer" positive stimuli. These findings add to the existing literature on the positivity effect on temporal source memory and highlighted the importance of considering the POV in relation to the emotional valence.

The effects of prefrontal tDCS and hf-tRNS on the processing of positive and negative emotions evoked by video clips in first- and third-person.

The causal role of the cerebral hemispheres in positive and negative emotion processing remains uncertain. The Right Hemisphere Hypothesis proposes right hemispheric superiority for all emotions, while the Valence Hypothesis suggests the left/right hemisphere's primary involvement in positive/negative emotions, respectively. To address this, emotional video clips were presented during dorsolateral prefrontal cortex (DLPFC) electrical stimulation, incorporating a comparison of tDCS and high frequency tRNS stimulation techniques and manipulating perspective-taking (first-person vs third-person Point of View, POV). Four stimulation conditions were applied while participants were asked to rate emotional video valence: anodal/cathodal tDCS to the left/right DLPFC, reverse configuration (anodal/cathodal on the right/left DLPFC), bilateral hf-tRNS, and sham (control condition). Results revealed significant interactions between stimulation setup, emotional valence, and POV, implicating the DLPFC in emotions and perspective-taking. The right hemisphere played a crucial role in both positive and negative valence, supporting the Right Hemisphere Hypothesis. However, the complex interactions between the brain hemispheres and valence also supported the Valence Hypothesis. Both stimulation techniques (tDCS and tRNS) significantly modulated results. These findings support both hypotheses regarding hemispheric involvement in emotions, underscore the utility of video stimuli, and emphasize the importance of perspective-taking in this field, which is often overlooked.

A comparative analysis of opioid-free and opioid-sparing anaesthesia techniques for laparoscopic ovariectomy in healthy dogs.

OBJECTIVE: To compare the perioperative analgesic effects of an opioid-free (OFA) and an opioid-sparing (OSA) anaesthetic protocol in dogs undergoing laparoscopic ovariectomy. STUDY DESIGN: Prospective, randomized, blinded, clinical trial. ANIMALS: A group of 28 client-owned dogs. METHODS: Dogs were allocated to one of two groups. The OFA group was administered intramuscular (IM) dexmedetomidine 5 µg kg-1 and ketamine 1 mg kg-1, followed by two intraoperative constant rate infusions (CRIs) of dexmedetomidine (3 µg kg-1 hour-1) and lidocaine (1 mg kg-1 loading dose, 2 mg kg-1 hour-1). The OSA group was administered IM dexmedetomidine 5 µg kg-1, ketamine 1 mg kg-1 and methadone 0.2 mg kg-1, followed by two intraoperative saline CRIs. In both groups, anaesthesia was induced with intravenous (IV) propofol 2 mg kg-1 and diazepam 0.2 mg kg-1 and maintained with isoflurane. Rescue dexmedetomidine (0.5 µg kg-1) was administered IV if there was a 20% increase in cardiovascular variables compared with pre-stimulation values. Ketorolac (0.5 mg kg-1) was administered IV when the surgery ended. Postoperative analgesia was evaluated using the Short Form-Glasgow Composite Measure Pain Scale and methadone (0.2 mg kg-1) was administered IM if the pain score was ≥ 6/24. Statistical analysis included mixed analysis of variance, Chi-square test and Mann-Whitney U test. RESULTS: There were no significant differences in the intraoperative monitored variables between groups. The OFA group showed a significantly lower intraoperative rescue analgesia requirement (p = 0.016) and lower postoperative pain scores at 3 (p =0.001) and 6 (p < 0.001) hours. No dogs were administered rescue methadone postoperatively. CONCLUSIONS AND CLINICAL RELEVANCE: Although both groups achieved acceptable postoperative pain scores with no need for further intervention, the analgesic efficacy of the OFA protocol was significantly superior to that of the OSA protocol presented and was associated with a lower intraoperative rescue analgesia requirement and early postoperative pain scores.

Detecting implicit and explicit facial emotions at different ages.

Emotions are processed in the brain through a cortical route, responsible for detailed-conscious recognition and mainly based on image High Spatial Frequencies (HSF), and a subcortical route, responsible for coarse-unconscious processing and based on Low SF (LSF). However, little is known about possible changes in the functioning of the two routes in ageing. In the present go/no-go online task, 112 younger adults and 111 older adults were asked to press a button when a happy or angry face appeared (go) and to inhibit responses for neutral faces (no-go). Facial stimuli were presented unfiltered (broadband image), filtered at HSF and LSF, and hybrids (LSF of an emotional expression superimposed to the HSF of the same face with a neutral expression). All stimuli were also presented rotated on the vertical axis (upside-down) to investigate the global analysis of faces in ageing. Results showed an overall better performance of younger compared to older participants for all conditions except for hybrid stimuli. The expected face-inversion effect was confirmed in both age groups. We conclude that, besides an overall worsening of the perceptual skill with ageing, no specific impairment in the functioning of both the cortical and the subcortical route emerged.

The Predictive Role of the Posterior Cerebellum in the Processing of Dynamic Emotions.

Recent studies have bolstered the important role of the cerebellum in high-level socio-affective functions. In particular, neuroscientific evidence shows that the posterior cerebellum is involved in social cognition and emotion processing, presumably through its involvement in temporal processing and in predicting the outcomes of social sequences. We used cerebellar transcranial random noise stimulation (ctRNS) targeting the posterior cerebellum to affect the performance of 32 healthy participants during an emotion discrimination task, including both static and dynamic facial expressions (i.e., transitioning from a static neutral image to a happy/sad emotion). ctRNS, compared to the sham condition, significantly reduced the participants' accuracy to discriminate static sad facial expressions, but it increased participants' accuracy to discriminate dynamic sad facial expressions. No effects emerged with happy faces. These findings may suggest the existence of two different circuits in the posterior cerebellum for the processing of negative emotional stimuli: a first-time-independent mechanism which can be selectively disrupted by ctRNS, and a second time-dependent mechanism of predictive "sequence detection" which can be selectively enhanced by ctRNS. This latter mechanism might be included among the cerebellar operational models constantly engaged in the rapid adjustment of social predictions based on dynamic behavioral information inherent to others' actions. We speculate that it might be one of the basic principles underlying the understanding of other individuals' social and emotional behaviors during interactions.

The impact of catastrophic events on the sex ratio at birth: A systematic review.

OBJECTIVE: The impact of maternal stress on birth outcomes is well established in the scientific research. The sex ratio at birth (SRB), namely the ratio of male to female live births, shows significant alteration when mothers experience acute stress conditions, as proposed by the Trivers-Willard Hypothesis. We aimed to synthetize the literature on the relationship between two exogenous and catastrophic stressful events (natural disasters and epidemics) and SRB. METHODS: A systematic search was run in Scopus, PubMed, Web of Science, and Cochrane Library, until March 9, 2023. The search produced 1336 articles and 25 articles met the inclusion criteria. We found seven case-control studies and 18 observational studies. Most of studies investigated the impact of earthquakes and other natural disasters. Only seven studies examined the effect of epidemics or pandemics. RESULTS: The results of the studies seem inconsistent, as 16 studies found a decline in SRB, three found a rise, four did not record any change and two studies gave contradictory results. The period and population analyzed, the source of information, the method of variance analysis in the SRB, and the failure to assess confounding variables may have influenced the incongruence of the results. CONCLUSION: Our findings contribute to improve the knowledge about the relationship between socio-ecological factors and SRB. Future studies should investigate the mechanisms by which this relationship impacts public health, in particular the health of pregnant women and their newborn, through an accurate and consistent methodology that also includes confounding factors.

Virtual reality and cognitive rehabilitation for older adults with mild cognitive impairment: A systematic review.

Virtual Reality (VR) has been gaining increasing attention as a potential ecological and effective intervention system for treating Mild Cognitive Impairment (MCI). However, it remains unclear the efficacy and effectiveness of VR-based cognitive rehabilitation therapy (VR-CRT) in comparison with cognitive rehabilitation therapy (CRT). Consequently, a systematic review on Pubmed, Scopus, PsycInfo, and Web Of Science was conducted to assess the state of the art of the literature published between 2003 and April 2023. Only articles that adopted CRT as control group and that included some measure of at least one domain among overall cognitive function, executive function and functional status were included. Participants needed to be older adults aged 65 or over with a diagnosis of MCI. The risk of bias and the quality of evidence were assessed using the Version 2 of the Cochrane risk-of-bias tool for randomized trials. Initially, 6503 records were considered and screened after removing duplicates (n = 1321). Subsequently, 81 full texts were assessed for eligibility. Four articles met the inclusion criteria but 2 of them were merged as they were describing different outcomes of the same research project. Consequently, 3 overall studies with a total of 130 participants were included in the final analysis. Due to the high heterogeneity in the methodology and outcome measures employed, it was not possible to conduct a meta-analysis. Included studies used semi-immersive (k = 2) and full-immersive (k = 1) VR systems in their research. Two articles evaluated overall cognitive function through the MoCA together with specific tests for executive functions (n = 69), while one study adopted a comprehensive neuropsychological battery to evaluate both cognitive function and executive function (n = 61). Finally, one study evaluated functional status through instrumental activities of daily living (n = 34). A However, the limited number of studies, the small sample size, and the potential issues with the quality and methodology of these studies that emerged from the risk of bias assessment may raise doubts about the reliability of their results. Nevertheless, although scarce, results of the present review suggest that VR-CRT may be paramount in treating MCI for its additional ecological and adaptive advantages, as all of the studies highlighted that it was at least as effective as conventional CRT for all the outcome measures. Therefore, more rigorous research that compares VR-CRT and CRT is needed to understand the degree to which VR-CRT is effective with older adults with MCI and the potential role of immersion to influence its efficacy. Indeed, these preliminary findings highlight the need for the development of standardized VR protocols, as the integration of such technology into clinical practice may help improve the quality of life and cognitive outcomes for this growing demographic.

The effect of aging and emotions on time processing.

BACKGROUND: Time perception is an automatic process that can be influenced by intrinsic and extrinsic factors. AIMS: This study aimed to investigate the effect of age and emotions on the ability to keep track of short suprasecond intervals. METHODS: Younger adults (N = 108, age range: 18-35) and older adults (N = 51, age range: 65-87) were asked to reproduce, bisect, or double the duration of facial stimuli randomly presented for 1500, 3000, and 4500 ms. The experiment included facial stimuli with positive, negative, or neutral expressions. RESULTS: The participants across age correctly reproduced intervals but overestimated and underestimated them when asked to bisect and double the intervals, respectively. Overall, when faces were presented with a positive or negative expression, an overestimation of time intervals emerged compared to faces with neutral expressions. Emotions had a greater effect on older adults, who showed a greater overestimation of positive facial expressions and an underestimation of sad, but not angry, facial expressions. DISCUSSION: The results provide evidence that time perception is influenced by age and emotions, with older adults showing a greater effect of emotions on time processing. CONCLUSION: The study suggests an interaction among time processing, age, and emotions, highlighting an automatic relationship among these domains, often considered independent.

Changing Decisions: The Interaction between Framing and Decoy Effects.

BACKGROUND: Cognitive biases are popular topics in psychology and marketing, as they refer to systematic cognitive tendencies in human thinking that deviate from logical and rational reasoning. The framing effect (FE) and the decoy effect (DE) are examples of cognitive biases that can influence decision making and consumer preferences. The FE involves how options are presented, while the DE involves the addition of a third option that influences the choice between the other two options. METHODS: We investigated the interaction between the FE and the DE in the case of both incongruent (ID) and congruent (CD) decoys in a sample of undergraduates (n = 471). The study had a two (positive vs. negative valence) × three (original, congruent decoy, incongruent decoy) within-subject design. RESULTS: The ID option reduces the FE in both positive- and negative-framed conditions compared to the controls, while adding the CD option increases the FE only in the positive-framed condition. Additionally, the inclusion of the CD option enhances the level of decision confidence, whereas no significant differences were found in the ID condition. CONCLUSIONS: Our findings gave new insights into the interplay between two of the most frequent cognitive biases.

Continuous positive airway pressure ventilation in dogs with acute cardiogenic pulmonary edema is associated with improved clinical parameters and reduced diuretic and oxygen requirements.

OBJECTIVE: To retrospectively compare efficacy of a continuous positive airway pressure (CPAP) helmet against standard oxygen supplementation (STD) administered by nasal cannulae in dogs with acute cardiogenic pulmonary edema (ACPE). ANIMALS: 83 dogs (STD group, n = 41; CPAP group, 42) hospitalized for ACPE (January 2019 to April 2021). METHODS: Mean respiratory rate, heart rate, systolic arterial pressure, and rectal body temperature were compared between and within groups before and at 1 (T1), 2 (T2), 3 (T3), 6 (T6), and 12 (T12) hours from the beginning of STD/CPAP therapy. Duration of oxygen supplementation, hospitalization time, total diuretic dose, additional pharmacological interventions and mortality rates were compared between groups. The veterinary bedside lung ultrasound in emergency score, thoracic radiographs, and arterial blood parameters were compared between and within groups before and at the end of CPAP/STD therapy. RESULTS: Within both groups, clinical parameters decreased during the observation period. Mean respiratory rate and heart rate were significantly lower in the CPAP group than the STD group at T1, T2, T3, T6, and T12. Mean systolic arterial pressure was significantly lower in the CPAP group than the STD group at T2, T3, T6, and T12. Mean oxygen supplementation duration, cumulative loop diuretic dose, and both veterinary bedside lung ultrasound in emergency score and arterial PaCO2 at the end of CPAP/STD therapy were significantly lower in the CPAP group than the STD group. No significant differences were observed in hospitalization time and mortality rates. CLINICAL RELEVANCE: The addition of helmet CPAP compared with standard oxygen administration showed a faster clinical improvement with lower cumulative loop diuretic and shorter oxygen supplementation in dogs hospitalized for ACPE.

Investigating Auditory Perception at Europe's Highest Mountain Lodge.

Altitude hypoxia can impair sensory and cognitive functions, from causing slowed responses to sensory hallucinations. In a field study, we tested 12 expeditioners at varied altitudes (low: 1696 m; high: 4556 m) with a simple auditory detection task and a dichotic listening paradigm in which a voice was presented, lateralized, within a binaural white noise stream. Slower reaction times and a reduced right ear advantage might be expected at high (vs. low) altitude, due to hypoxia. The participants' performances on both tasks did not differ between conditions, revealing that these functions are resistant to short-term hypoxia in young healthy adults.

Time reproduction, bisection and doubling: a novel paradigm to investigate the effect of the internal clock on time estimation.

Time perception is not always veridical, but it can be modulated by changes in internal and external context. The most-acknowledged theory in this regard hypothesises the existence of an internal clock allowing us to subjectively estimate time intervals. The aim of the present study is to investigate the possible effect of such an internal clock, measured as the ability to reproduce a target duration, in the mental manipulation of time: 63 healthy participants were asked to Bisect and to Double reference time intervals, besides Reproducing them. Moreover, to investigate whether time processing might be predicted by individual differences, handedness, anxiety, and personality traits were also assessed by means of standardized questionnaires. Results show that participants correctly Reproduce time intervals (internal clock), but they overestimate time intervals during Bisection and underestimate them during Doubling. We explain this unexpected pattern of results as a kind of aftereffect, due to the short-term retention (adaptation) to the subjective representation of shorter (Bisection) vs longer (Doubling) intervals, respectively. Moreover, hierarchic regression models reveal that some personality traits can predict Bisection accuracy, but they clearly show that the best predictor for both Bisection and Doubling is the accuracy in Reproducing time intervals, confirming the fundamental role of the internal clock in time estimation. We conclude that time estimation is a unique skill, mostly independent from inter-individual differences, and the new paradigms introduced here (bisection vs doubling) reveal that the correct functioning of the internal clock also explains the ability to mentally manipulate the time.

A neural signature of exposure to masked faces after 18 months of COVID-19.

In the last two years, face-to-face interactions have drastically changed worldwide, because of the COVID-19 pandemic: the persistent use of masks has had the advantage of reducing viral transmission, but it has also had the cost of impacting on the perception and recognition of social information from faces, especially emotions. To assess the cerebral counterpart to this condition, we carried out an EEG experiment, extracting Event-Related Potentials (ERPs) evoked by emotional faces with and without surgical masks. Besides the expected impairment in emotion recognition in both accuracy and response times, also the classical face-related ERPs (N170 and P2) are altered by the presence of surgical masks. Importantly, the effect is stronger in individuals with a lower daily exposure to masks, suggesting that the brain must adapt to an extra constraint in decoding social input, due to masks hiding crucial facial information.

Neurovegetative and Emotional Modulation Induced by Mozart's Music.

INTRODUCTION: Since decades, the "Mozart effect" has been studied. However, the diverse effects of Mozart's music components have not been yet defined. Authors aimed to identify a differential response to short-term exposure to Mozart's music, or to its rhythmic signature only, on subjective and objective measures. METHODS: The Mozart Sonata in A major K 331 (Mozart), the same piece consisting only of beat (Destructured), and duration-matched silence were administered to 25 healthy young adults, stood supine in a relaxing setting. The Italian Mood Scale questionnaire was administered before and after each listening. Heart rate variability (HRV) metrics were calculated from ECG recording, and breath flow was registered during experiments. RESULTS: After Destructured, there was no change of fatigue and tension. After Mozart, fatigue was significantly reduced (and a tendency appeared for tension), whereas vigor was not. Breathing rate tended to be higher during Mozart. The nonlinear parameter HFD of HRV analysis, even though not significantly, was slightly lower during Destructured; Poincaré plots SD1 and SD2 tended to be lower during Mozart. DISCUSSION/CONCLUSION: Mozart's music may allow to maintain arousal during relaxing condition. Psychological response of music and physiological dynamics were not necessarily entangled. Musical pieces based on individual physiological signature may lead musical psychological interventions.

Environmental risks to humans, the first database of valence and arousal ratings for images of natural hazards.

Due to their relevance for the entire society, environmental hazards have largely been investigated in terms of their psychological effects. However, a complete image database comprising different categories of catastrophes has not been proposed yet. We selected 200 photographs of the most frequent natural disasters with the aim to collect the emotional reactions of observers. In particular, 20 stimuli were selected for each of the following 10 categories: earthquake, volcanic activity, lightning, hailstorm, drought, fire, landslide, epidemic, and neutral and positive images as control categories. A sample of 605 participants completed an online survey, in which they were asked to rate either the valence or the arousal of each stimulus, by using a Self-Assessment Manikin. The Environmental Risk to Humans database associates the emotional reactions to these visual stimuli, together with the demographics of the sample (e.g., gender, age, marital status, income, previous experience of natural disasters). The database constitutes a tool to explore human reactions to natural hazards, providing a controlled set of stimuli for different types of catastrophes.

Exploring brain activity for positive and negative emotions by means of EEG microstates.

Microstate analysis applied to electroencephalographic signals (EEG) allows both temporal and spatial imaging exploration and represents the activity across the scalp. Despite its potential usefulness in understanding brain activity during a specific task, it has been mostly exploited at rest. We extracted EEG microstates during the presentation of emotional expressions, presented either unilaterally (a face in one visual hemifield) or bilaterally (two faces, one in each hemifield). Results revealed four specific microstate's topographies: (i) M1 involves the temporal areas, mainly in the right hemisphere, with a higher occurrence for stimuli presented in the left than in the right visual field; (ii) M2 is localized in the left temporal cortex, with higher occurrence and coverage for unilateral than bilateral presentations; (iii) M3, with a bilateral temporo-parietal localization, shows higher coverage for bilateral than unilateral presentation; (iv) M4, mainly localized in the right fronto-parietal areas and possibly representing the hemispheric specialization for the peculiar stimulus category, shows higher occurrence and coverage for unilateral stimuli presented in the left than in the right visual field. These results suggest that microstate analysis is a valid tool to explore the cerebral response to emotions and can add new insights on the cerebral functioning, with respect to other EEG markers.

Sedative Effects of Intramuscular Dexmedetomidine and Ketamine at Sub-Anesthetic Dose Alone or in Combination with Methadone in Healthy Dogs.

The aim of the present study was to compare sedation quality and cardiorespiratory parameters in healthy dogs after intramuscular injection of dexmedetomidine and ketamine with or without methadone. Forty client-owned dogs were randomly divided into two groups and received IM dexmedetomidine (5 µg kg-1) and ketamine (1 mg kg-1), associated (DKM group) or not (DK group) with methadone (0.2 mg kg-1). Sedation, heart rate (HR), respiratory rate (ƒR), mucous membrane and rectal temperature were recorded at baseline (T0) and after 5 (T5), 10 (T10) and 20 (T20) minutes. From T10, cardiac rhythm was monitored with a continuous lead II electrocardiogram. Ease of venous catheter placement, total propofol dose and any apnea episodes were recorded. Sedation was significantly greater in the DKM group, and a significant increase from T5 to T20 within DKM (P = .0002) and DK (P = .008) was also observed. Within each group, HR was significantly lower at all time points compared to baseline. No significant differences between groups were found in the number of arrhythmogenic events (atrioventricular blocks). In both group ƒR decreased over time. The propofol dose required for anesthesia induction was significantly lower (P = .027) in the DKM group. In conclusion, a good level of sedation was achieved in both groups, although this was greater in DKM. Smooth animal-operator interaction and ease of venous catheter placement showed that DK was a useful sedative protocol in healthy patients.