ABSTRACT
The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ultimately produce. We used radio astrometry to refine the distance to the black hole x-ray binary Cygnus X-1, which we found to be [Formula: see text] kiloparsecs. When combined with archival optical data, this implies a black hole mass of 21.2 ± 2.2 solar masses, which is higher than previous measurements. The formation of such a high-mass black hole in a high-metallicity system (within the Milky Way) constrains wind mass loss from massive stars.
ABSTRACT
UNLABELLED: In paediatric patients, esophagogastroduodenoscopy (EGD) is commonly performed with the use of sedation. The aim of the study was to compare the effectiveness of propofol and midazolam in providing procedural amnesia and controlling behaviour in children undergoing diagnostic EGD. Children (9-16 years), classified to the first or second class of the American Society of Anaesthesiologists' physical status classification referred for EGD, were randomly assigned to receive propofol with alfentanyl or midazolam with alfentanyl for sedation during the procedure. Within 120 min after the procedure, patients were repeatedly investigated for memory of the procedure and for memory of pain intensity during EGD with the use of the visual analogue scale. Activity and cooperation of the patient during the procedure was assessed with the relative adequacy scale. Of the 51 children, 48 completed the study. Propofol was significantly better than midazolam in inducing amnesia of procedural pain (mean difference 11.53 mm; 95 % confidence interval [CI] 0.96 to 22.10), loss of memory of the procedure (relative risk 0.4; 95 % CI 0.21 to 0.59) and controlling behaviour (relative risk 2.12; 95 % CI 1.33 to 3.36). CONCLUSION: In children sedated for EGD, propofol is significantly better than midazolam at providing procedural amnesia and controlling behaviour during the procedure.
Subject(s)
Alfentanil/therapeutic use , Analgesics, Opioid/therapeutic use , Endoscopy, Gastrointestinal/methods , Hypnotics and Sedatives/therapeutic use , Midazolam/therapeutic use , Propofol/therapeutic use , Adolescent , Alfentanil/administration & dosage , Analgesics, Opioid/administration & dosage , Child , Conscious Sedation/methods , Double-Blind Method , Drug Therapy, Combination , Female , Humans , Hypnotics and Sedatives/administration & dosage , Male , Memory/drug effects , Midazolam/administration & dosage , Pain , Pain Measurement , Propofol/administration & dosage , Prospective StudiesABSTRACT
Endotracheal suction is essential to keep the respiratory capacity of the bronchial tree. The aim of this study was to establish the principles reducing potential side-effects, like hypoxia, bradycardia, hypotension, arrhythmia, nosocomial infections. Analysing the literature we have selected the following major beneficial factors: 1:2 to 2:3 cathether - tracheal tube diameter ratio, individual adjustment of the suctioning frequency, maximal duration of the procedure capped at 10-15 sec., minimal effective suctioning pressure of 80-100 mmHg. We have also determined that the following procedures should be also taken into consideration: preoxygenation (only for unstable patients), sedation and analgesia. We have concluded with the comparison of the two suction systems, pointing out that, especially for unstable patients, closed-suction system proves more suitable.
