Patients with sleep apnea often present with cardiac diseases and breathing difficulties, with a high risk of postoperative respiratory depression. We conducted a randomized, double-blind, prospective study in 30 adult patients with obstructive sleep apnea, undergoing elective ear-nose-throat surgery. The patients were randomly assigned to receive placebo or clonidine (2 microg/kg oral) the night before and the next morning 2 h before surgery. Spo2, heart rate, mean arterial blood pressure, snoring, and oronasal airflow were monitored for 36 h. A standard anesthesia was used consisting of propofol and remifentanil. Anesthetic drug consumption, postoperative analgesics, and pain score were recorded. In the clonidine group, mean arterial blood pressures were significantly lower during induction, operation, and emergence from anesthesia. Both propofol dose required for induction (190 +/- 32.2 mg) and anesthesia (6.3 +/- 1.3 mg . kg(-1).h(-1)) during surgery were significantly reduced in the clonidine group compared with the placebo group (induction 218 +/- 32.4, anesthesia 7.70 +/- 1.5; P < 0.05). Piritramide consumption (7.4 +/- 5.1 versus 14.2 +/- 8.5 mg; P < 0.05) and analgesia scores were significantly reduced in the clonidine group. Apnea and desaturation index were not different between the groups, whereas the minimal postoperative oxygen saturation on the day of surgery was significantly lower in the placebo than in the clonidine group (76.7% +/- 8.0% versus 82.4% +/- 5.8%; P < 0.05). We conclude that oral clonidine premedication stabilizes hemodynamic variables during induction, maintenance, and emergence from anesthesia and reduces the amount of intraoperative anesthetics and postoperative opioids without deterioration of ventilation.
To investigate the physiological role of granulocyte colony-stimulating factor (G-CSF) and granulocytemacrophage colony-stimulating factor (GM-CSF) in the adaptation mechanisms of myelopoiesis to enhanced demand, we studied both cytokines and their myeloid target cells in hematologically healthy patients suffering from acute bacterial infections. Endogenous serum levels of G-CSF and GM-CSF, granulocyte-macrophage colony-forming cell (GM-CFC) concentrations, and differential counts were determined for the peripheral blood of 57 patients with clinically apparent bacterial infections (26 males and 31 females aged 16 to 89 years) and 18 healthy controls (8 males and 10 females aged 23 to 84 years). Patients were selected for acute-phase protein and at least two additional clinical signs reflecting a bacterial infection. Patients showed significantly higher numbers of myeloid progenitor cells than controls (median, 68 versus 26 GM-CFC/ml; P Յ 0.01). G-CSF but not GM-CSF levels were found to be elevated (Ն50 to 863 pg/ml). In the acute stage of infection, progenitor and cytokine levels were not influenced by gender, differences in therapy, or localization of the infection. Progenitor and G-CSF levels were not associated with absolute neutrophil counts or C-reactive protein. However, a negative correlation between number of GM-CFC per milliliter and age (R ؍ ؊0.47; P Յ 0.001) and an inverse relationship between the incidence of high GM-CFC concentrations and elevated G-CSF levels (phi ؍ ؊0.34; P Յ 0.01) were found. Combining both parameters into a cytokine-progenitor pattern, we observed a highly significant age-dependent response of myelopoiesis to inflammation (P Յ 0.001). Younger patients had high progenitor counts (>75 GM-CFC/ml) associated with G-CSF levels below 50 pg/ml, whereas for the older patients, the reverse pattern was predominant. The results indicate that the age-dependent myelopoietic response to acute bacterial infections is characterized by an inverse relationship between progenitor cells and G-CSF. The observed cytokine-progenitor patterns could have implications for therapy with G-CSF and the prognosis of infectious diseases.
N-Acetylcysteine, known as a radical scavenger, was examined for its influence on the radiotolerance of progenitor cells of granulocytopoiesis. Added before and after irradiation in a dose of 2 mg/ml to suspension cultures of non-adherent low-density human bone marrow cells N-acetylcysteine (AcCys) clearly improved the survival. The D0 value of the survival curve for granulocyte/macrophage colony-forming cells increased by a factor of 1.56 as compared to non-treated control suspensions. The improvement of radiation tolerance is probably not only based on the radical scavenger properties (radioprotective component) of AcCys, but also on the support of repair processes.
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