The Clinical Utility of Noninvasive Pulse Co-oximetry Hemoglobin Measurements in Dark-Skinned Critically Ill Patients.

BACKGROUND: The primary objective of this study was to assess the clinical usefulness of a point-of-care device which measures hemoglobin noninvasively (SpHb) in a group of critically ill participants with dark skin pigmentation. METHODS: One hundred forty-six adult and pediatric participants from a multidisciplinary intensive care unit had intermittent readings of noninvasive hemoglobin measurements performed at a minimum of 4 hourly intervals. A total of 371 readings were analyzed. Concurrent blood samples were taken to assess hemoglobin levels using point-of-care blood gas analyzer, as well as sent to a central laboratory where hemoglobin was measured using the sodium lauryl sulfate method. Bland-Altman plots were constructed to assess the agreement between results from the 2 point-of-care devices with the reference standard (laboratory hemoglobin). RESULTS: SpHb exhibited significant bias when compared to laboratory hemoglobin, while blood gas hemoglobin did not. Mean bias for SpHb was +1.64 with limits of agreement of -1.03 to 4.31 compared to blood gas hemoglobin which showed a bias of 0.26 and limits of agreement of -0.84 to 1.37. The magnitude of the bias for SpHb increased with increasing mean hemoglobin levels. Of all the additional study variables assessed for effect on the bias, only Acute Physiology and Chronic Health Evaluation II score in adult patients (P < .0001) and mean arterial blood pressure (P = .001) had an effect. Skin pigmentation did not have any effect on the magnitude of bias. CONCLUSIONS: Noninvasive Hemoglobin measurement is a promising tool in dark-skinned critically ill patients with low hemoglobin levels, but requires further refinements for it to have clinical usefulness.

The development of descending projections from the brainstem to the spinal cord in the fetal sheep.

BACKGROUND: Although the fetal sheep is a favoured model for studying the ontogeny of physiological control systems, there are no descriptions of the timing of arrival of the projections of supraspinal origin that regulate somatic and visceral function. In the early development of birds and mammals, spontaneous motor activity is generated within spinal circuits, but as development proceeds, a distinct change occurs in spontaneous motor patterns that is dependent on the presence of intact, descending inputs to the spinal cord. In the fetal sheep, this change occurs at approximately 65 days gestation (G65), so we therefore hypothesised that spinally-projecting axons from the neurons responsible for transforming fetal behaviour must arrive at the spinal cord level shortly before G65. Accordingly we aimed to identify the brainstem neurons that send projections to the spinal cord in the mature sheep fetus at G140 (term = G147) with retrograde tracing, and thus to establish whether any projections from the brainstem were absent from the spinal cord at G55, an age prior to the marked change in fetal motor activity has occurred. RESULTS: At G140, CTB labelled cells were found within and around nuclei in the reticular formation of the medulla and pons, within the vestibular nucleus, raphe complex, red nucleus, and the nucleus of the solitary tract. This pattern of labelling is similar to that previously reported in other species. The distribution of CTB labelled neurons in the G55 fetus was similar to that of the G140 fetus. CONCLUSION: The brainstem nuclei that contain neurons which project axons to the spinal cord in the fetal sheep are the same as in other mammalian species. All projections present in the mature fetus at G140 have already arrived at the spinal cord by approximately one third of the way through gestation. The demonstration that the neurons responsible for transforming fetal behaviour in early ontogeny have already reached the spinal cord by G55, an age well before the change in motor behaviour occurs, suggests that the projections do not become fully functional until well after their arrival at the spinal cord.

A map of the major nuclei of the fetal sheep brainstem.

The fetal sheep has been used to investigate a wide range of developmental and pathological processes such as the effect of severe hypoxia, asphyxia, or intrauterine infection on the brain but, until now, there has been no complete description of the normal anatomical organisation of neuronal groups to facilitate interpretation of these studies. In this paper, we describe the major nuclei of the fetal sheep brainstem based on a study of 5 fetal sheep at 140 days of gestation (G140: term is G147). Nuclei were identified with the aid of brain atlases available for other species, and from the previously published, partial descriptions available for the sheep. Fifty-five distinct nuclei were identified after Nissl (thionin) staining, and their caudal and rostral margins were defined. This paper provides an easy reference to the position of the major nuclei within the fetal sheep brainstem, and can be used as a guide for future studies examining the organisation of neuronal populations under normal and pathological conditions in this animal model.

White lie-telling in children for politeness purposes.

Prosocial lie-telling behavior in children between 3 and 11 years of age was examined using an undesirable gift paradigm. In the first condition, children received an undesirable gift and were questioned by the gift-giver about whether they liked the gift. In the second condition, children were also given an undesirable gift but received parental encouragement to tell a white lie prior to being questioned by the gift-giver. In the third condition, the child's parent received an undesirable gift and the child was encouraged to lie on behalf of their parent. In all conditions, the majority of children told a white lie and this tendency increased with age. Coding of children's facial expressions using Ekman and Friesen's (1978) Facial Action Coding System revealed significant but small differences between lie-tellers and control children in terms of both positive and negative facial expressions. Detailed parental instruction facilitated children's display of appropriate verbal and nonverbal expressive behaviors when they received an undesirable gift.

Chemical coding of sympathetic neurons controlling the tarsal muscle of the rat.

Sympathetic axons in the upper eyelid and in tissues in the superior retro-orbital space were examined for NPY immunoreactivity. Sympathetic nerve terminals containing co-localised NPY were associated with blood vessels, the conjunctiva and the Meibomian glands. The acini of the Harderian gland completely lacked sympathetic innervation. Sympathetic axons lacking NPY were only found in the tarsal muscle. In addition, a minority of terminals, located in the more proximal part of the tarsal muscle, contained weak immunoreactivity to NPY. Injections of the retrograde tracer, Fast Blue, into the eyelid or retro-orbital space labelled postganglionic somata in the superior cervical ganglion. While many retrogradely labelled somata were immunoreactive for NPY, around half lacked NPY immunoreactivity and so are likely to project to the tarsal muscle. Most of the retrogradely labelled postganglionic somata lacking NPY were surrounded by terminals immunoreactive for met-enkephalin, leu-enkephalin and met-enkephalin arg-gly-leu which were all found to be present in the same nerve terminals. Sectioning the cervico-sympathetic trunk eliminated all enkephalin-immunoreactive pericellular baskets. Many enkephalin-immunoreactive pericellular terminals contained co-localised VAChT, calretinin and calbindin immunoreactivity, but completely lacked nitric oxide synthase immunoreactivity. A second population of nerve terminals that were immunoreactive for nitric oxide synthase also surrounded tarsal muscle-projecting neurons, but these terminals lacked immunoreactivity to enkephalin. Thus, postganglionic neurons projecting to the tarsal muscle are of at least two chemical phenotypes (with or without NPY) and they receive convergent input from at least two populations of preganglionic neurons with distinctive chemical phenotypes.