Spinal anesthesia in a designated block bay for total joint arthroplasty: improving operating room efficiency.

BACKGROUND: Creating highly efficient operating room (OR) protocols for total joint arthroplasty (TJA) is a challenging and multifactorial process. We evaluated whether spinal anesthesia in a designated block bay (BBSA) would reduce time to incision, improve first case start time and decrease conversion to general anesthesia (GA). METHODS: Retrospective cohort study on the first 86 TJA cases with BBSA from April to December 2018, compared with 344 TJA cases with spinal anesthesia performed in the OR (ORSA) during the same period. All TJA cases were included if the anesthetic plan was for spinal anesthesia. Patients were excluded if circumstances delayed start time or time to incision (advanced vascular access, pacemaker interrogation, surgeon availability). Data were extracted and analyzed via a linear mixed effects model to compare time to incision, via a Wilcoxon rank-sum test to compare first case start time, and via a Fisher's exact test to compare conversion to GA between the groups. RESULTS: In the mixed effect model, the BBSA group time to incision was 5.37 min less than the ORSA group (p=0.018). The BBSA group had improved median first case start time (30.0 min) versus the ORSA group (40.5 min, p<0.0001). There was lower conversion to GA 2/86 (2.33%) in the BBSA group versus 36/344 (10.47%) in the ORSA group (p=0.018). No serious adverse events were noted in either group. CONCLUSIONS: BBSA had limited impact on time to incision for TJA, with a small decrease for single OR days and no improvement on OR days with two rooms. BBSA was associated with improved first case start time and decreased rate of conversion to GA. Further research is needed to identify how BBSA affects the efficiency of TJA.

Female preferences for temporal order of call components in the túngara frog: a Bayesian analysis.

We employed a Bayesian statistical approach to examine female preferences in the Neotropical frog Physalaemus pustulosus for the temporal relationship of the two parts of the conspecific advertisement call. The male advertisement call consists of a 'whine', which is necessary for species recognition, followed immediately by one or more 'chucks', which make the whine more attractive to females. We conducted 42 two-choice experiments with a total of 840 individual tests to compare the attractiveness of a whine with a chuck in a variety of positions relative to the start of the whine against a normal whine or against a normal whine/chuck. Females have a bimodal preference function for chuck position. Chucks placed in a variety of positions after the whine (including the position of a chuck in a normal call) were generally as attractive as a normal whine/chuck. Chucks placed before the whine were generally more attractive than a whine alone, and in some positions as attractive as the normal whine/chuck. Chucks overlapping the end of the whine make the call more attractive than a whine alone, but not as attractive as a normal whine/chuck, while chucks overlapping an initial portion of the whine beginning 50 ms into it are ignored; previous work (Wilczynski et al. 1995, Animal Behaviour, 49, 911-929) indicates this region to be critical for species recognition. These results suggest that female P. pustulosus have preferences for the temporal relationship of the two parts of the conspecific male advertisement call that far exceed the vocal signals produced by males, and that male calls have evolved calls to exploit one peak of this function. Copyright 1999 The Association for the Study of Animal Behaviour.

Phylogenetic influence on mating call preferences in female túngara frogs, Physalaemus pustulosus.

We evaluated how various phylogenetic models for estimating ancestral characters can influence studies of behavioural evolution. Previously we used a single model of evolution to estimate the values of call characters at ancestral nodes for the Physalaemus pustulosus species group and some close relatives (Ryan & Rand 1995, Science, 269, 390-392). We then synthesized these ancestral calls and measured the females' responses to such calls in phonotaxis experiments. We repeated the above procedure to determine the sensitivity of these results and conclusions to various models used to estimate the ancestral call characters. We asked whether: (1) different models gave different call estimates for the same nodes; (2) different call estimates at the same node were perceived as different by females; and (3) differences in female responses influenced previous conclusions. We used seven different models that varied in at least one of the following parameters: tree topology (bifurcating versus pectinate in-group trees), algorithms (local squared-change versus squared-change parsimony), tempo (gradual or punctuated evolution), and outgroups (two or three outgroup taxa used). Although different models often gave different call estimates for the same node, these different estimates often were not perceived as different by the females. These data reinforce our previous conclusions that: (1) the range of female preferences exceeds the known variation of the conspecific call; (2) females do not discriminate between the conspecific call and the call of their most recent ancestor; and (3) female responses may be context dependent, given that females differ in their responses to the same signal variation in discrimination and recognition experiments. Copyright 1999 The Association for the Study of Animal Behaviour.

Temporal call changes and prior experience affect graded signalling in the cricket frog.

We investigated how male cricket frogs Acris crepitans, alter their advertisement calls in response to broadcasts of synthetic calls that were either 'attractive' or 'aggressive'. The stimulus calls differed in temporal but not spectral characteristics. Male cricket frogs produced a more aggressive call when presented with the aggressive stimulus, indicating that they perceived the temporal differences between the two call categories. The direction and degree of temporal and spectral changes depended on the relative dominant frequency of the resident and opponent. If the resident's dominant frequency was initially higher than the stimulus frequency, the pattern of change in dominant frequency mirrored that seen for the temporal call characters. In contrast, if the resident's initial dominant frequency was below that of the stimulus, then the temporal and spectral changes were in opposite directions. Furthermore, stimulus order influenced whether males responded differently to playbacks of aggressive and attractive calls; males that received the aggressive call first produced more aggressive calls during the aggressive stimulus, while males that received the attractive call first produced similar calls in response to the two stimuli. This suggests that experience with different types of signals influences the subsequent calling behaviour of male cricket frogs. Copyright 1999 The Association for the Study of Animal Behaviour.

Consistency of female choice in the túngara frog: a permissive preference for complex characters

Previous phonotaxis experiments in the túngara frog, Physalaemus pustulosus, indicated a permissiveness in female preference that allows sexually selected complex call characters to be replaced with various alternative characters. Although they prefer complex to simple calls, females as a group did not discriminate between several alternative complex characters appended to the simple conspecific call. However, these studies did not address the possibility that the apparent permissiveness in female preference occurred because of an averaging of population data. The observed patterns in female preference could result from all females finding a certain set of call variants equally attractive, or from a polymorphism in female call preference. To discriminate between these two alternatives, consistency of mate choice was determined for three pairs of calls that elicited no phonotactic bias in population studies. Individual females did not repeatedly choose one stimulus of a pair over the other, demonstrating that the patterns of permissiveness observed in the population are paralleled by similar patterns within females. A broad preference for complex calls in the P. pustulosus species group would permit the evolution of sexually selected call variation through sensory exploitation. Copyright 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour.

Intraspecific variation in laryngeal and ear morphology in male cricket frogs (Acris crepitans)

In a previous report, the authors found significant population variation in the calls of cricket frogs (Acris crepitans) that could not be explained by geographic variation in body size alone. Here we extend that work by investigating intraspecific population variation in the morphological characteristics underlying acoustic communication in male cricket frogs from several sites in Texas. We measured the volumes of laryngeal and auditory components responsible for the generation or reception of species-specific vocalizations in male frogs from eight populations. We found significant differences among populations in body size, as well as all the laryngeal and ear components we measured. With the exception of vocal cord and extracolumella volumes, the volumes of these anatomical structures differ among populations independently of body size as determined by a covariate analysis with snout-vent length as the covariate. Call dominant frequency differs among populations in a clinal pattern and head width, arytenoid cartilage, vocal cord and dilator muscle volume show a similar pattern when the residuals of the regression of morphological component on SVL are assessed for this trend. The results show that both larynx and ear structures can change in size independently of body size, yielding significant geographic variation in the behavioral and physiological expressions of the acoustic communication system underlying mate choice.Copyright 1998 The Linnean Society of London

Evoked vocal response in male túngara frogs: pre-existing biases in male responses?

Female túngara frogs, Physalaemus pustulosus, are preferentially attracted to a whine-chuck advertisement call over a simple whine (Rand & Ryan 1981, Zeitschrift für Tierpsychologie, 57, 209-214). Females also show phonotactic preferences for the whine when a number of other heterospecific or artificial stimuli are added to it, and these calls tend to be as attractive to females as a whine-chuck (Ryan & Rand 1990, Evolution, 44, 305-314). We tested male túngara frogs with the same suite of stimuli using evoked vocal responses as a bioassay to examine sexual differences in responses to signal variation. A whine-chuck elicited greater responses from males than a whine-only. Artificial and heterospecific stimuli that enhanced call attractiveness to females also elicited greater vocal responses from males and, as with females, the effects of these stimuli were similar to that of the whine-chuck. Thus, in both sexes there are pre-existing biases for a suite of stimuli not produced by conspecifics. (c) 1998 The Association for the Study of Animal Behaviour.

Responses to conspecific and heterospecific olfactory cues in the swordtail Xiphophorus cortezi

Female Xiphophorus cortezi responded to olfactory cues from both conspecific males and heterospecific X. nigrensisX. montezumae males when given a choice between the stimulus and water. When given a choice between the conspecific and heterospecific cues, however, females demonstrated a strong preference for the conspecific stimulus. Of the two heterospecific species, females responded more strongly to their close relative X. nigrensis than they did to the more distantly related X. montezumaeMate recognition in northern swordtails is evidently not a simple process based upon a response to one variable, but the outcome of complex responses to information from at least both visual and olfactory cues.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour