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Patterns of care at the end of life vary in children with differing clinical and demographic characteristics. Because EOLC discussions are associated with greater focus on palliative care, strategies to enhance EOLC communications for pediatric patients should be further evaluated.

We studied ventilatory responsiveness to hypoxia and hypercapnia in anesthetized cats before and after exposure to 5 atmospheres absolute O2 for 90-135 min. The acute hyperbaric oxygenation (HBO) was terminated at the onset of slow labored breathing. Tracheal airflow, inspiratory (TI) and expiratory (TE) times, inspiratory tidal volume (VT), end-tidal PO2 and PCO2, and arterial blood pressure were recorded simultaneously before and after HBO. Steady-state ventilation (VI at three arterial PO2 (PaO2) levels of approximately 99, 67, and 47 Torr at a maintained arterial PCO2 (PaCO2, 28 Torr) was measured for the hypoxic response. Ventilation at three steady-state PaCO2 levels of approximately 27, 36, and 46 Torr during hyperoxia (PaO2 450 Torr) gave a hypercapnic response. Both chemical stimuli significantly stimulated VT, breathing frequency, and VI before and after HBO. VT, TI, and TE at a given stimulus were significantly greater after HBO without a significant change in VT/TI. The breathing pattern, however, was abnormal after HBO, often showing inspiratory apneusis. Bilateral vagotomy diminished apneusis and further prolonged TI and TE and increased VT. Thus a part of the respiratory effects of HBO is due to pulmonary mechanoreflex changes.

The (1,4)-a-D-glucan (a-D-glucan), derived from medicinal plant, Tinospora cordifolia, activates human lymphocytes with downstream synthesis of the pro-and anti-inflammatory cytokines, in vitro. We investigated physiological and immunological effects of a low and a high dose of a-D-glucan (0.5 and 10 mg/kg), in vivo, testing the hypothesis that intravenous administration of a-D-glucan does not affect haemodynamic, respiratory, haematological, and immune responses in normal rats. Male rats (300-400 g) were anaesthetized, tracheostomized, and catheterized in one femoral artery and vein. The mean arterial blood pressure and heart rate were continuously recorded. The baselines for gas exchange, differential blood cell count, and plasma concentration of TNF-a, IL-1b, IL-4, IL-6, and IFN-c were determined. Rats were then randomly assigned to controls (n ¼ 7), a low dose (0.5 mg/kg; n ¼ 10), and a high dose (10 mg/kg; n ¼ 7) of a-D-glucan for a six 6 hr study period. Gas exchange, differential cell count, plasma concentration of TNF-a, IL-1b, IL-4, IL-6, and IFN-c, and mean arterial blood pressure values remained within physiological range. Intravenous administration of 10 mg/kg a-D-glucan created tachycardia, associated with hyperventilation, and significant reductions in the blood haemoglobin and haematocrit concentrations. We suggest that these in vivo effects of a-D-glucan should be considered for future clinical and/or experimental trials.Extracts from a medicinal plant, Tinospora cordifolia, are shown to have anti-tumour activity [1,2], to reduce the pathological effects of endotoxic shock [3], and to inhibit lethal irradiation injury [4]. Studies suggest that glucans have modulating effects on inflammatory cytokines [5,6]. Extracts from other medicinal plants are known to enhance immune responses [7], and/or participate in scavenging of excessive reactive oxygen and nitrogen species [8,9]. The water-soluble polysaccharide (1,4)-a-d-glucan (a-d-glucan) is isolated from T. cordifolia and is known to activate different subsets of lymphocytes in vitro at 100 lg/ml [10]. This activation is followed by production of both pro-and antiinflammatory cytokines, such as TNF-a, IL-1b, IL-6, IL-12, IL-18, IFN-c, and MCP-1, involving Th1 pathway of T helper cell differentiation [5].The physiological effects of such immune-stimulating agents have been rarely studied. The half-life of glucans, given intravenously, is relatively short [11] and in practice multiple doses of glucans might be required to produce a maintained and significant change in inflammatory cytokine production. No study has examined the immediate effects of a single and relatively low dose of glucans, intravenously, in normal animals. In the present study, therefore, we tried to establish the physiological characteristics of a-d-glucan, to be considered for the design of future experimental and clinical trials. We tested whether intravenous administration of a-d-glucan can affect vital physiological variables, which are ordinarily used during critica...

There are significant gender differences in ventilation, gas exchange, and anesthetic requirements in rats subjected to critical care conditions. The gas-exchange values observed in these spontaneously breathing rats may represent the optimal levels attainable during pentobarbital anesthesia with normal lungs. They may serve as standards for ventilator settings in the rat models used for critical care studies.

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