Illuminating gravitational waves: A concordant picture of photons from a neutron star merger

Merging neutron stars offer an excellent laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of an electromagnetic counterpart (EM170817) with gravitational waves (GW170817) detected from merging neutron stars. By synthesizing a panchromatic data set, we demonstrate that merging neutron stars are a long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma rays seen in EM170817 are dissimilar to classical short gamma-ray bursts with ultrarelativistic jets. Instead, we suggest that breakout of a wide-angle, mildly relativistic cocoon engulfing the jet explains the low-luminosity gamma rays, the high-luminosity ultraviolet-optical-infrared, and the delayed radio and x-ray emission. We posit that all neutron star mergers may lead to a wide-angle cocoon breakout, sometimes accompanied by a successful jet and sometimes by a choked jet.

An optical spectrum of the afterglow of a γ-ray burst at a redshift of z = 6.295

The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe. Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 A due to Lyman alpha absorption at z approximately 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 +/- 0.002 was also detected, yielding the precise measurement of the redshift. The Si ii fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB.

Initial distribution volume of glucose is correlated with intrathoracic blood volume in hypovolaemia and following volume loading in dogs

BACKGROUND AND OBJECTIVE

Initial distribution volume of glucose (IDVG) reliably measures the central extracellular fluid volume in the presence of fluid gain or loss. We hypothesized that IDVG has a close relationship with intrathoracic blood volume (ITBV), which has recently been used as an indicator of cardiac preload. We therefore examined whether IDVG can correlate with ITBV in various fluid volume states.

METHODS

Fourteen anaesthetized mongrel dogs were mechanically ventilated. ITBV and cardiac output were measured by single transpulmonary thermodilution technique. IDVG and indocyanine green derived plasma volume (PV-ICG) were determined by the administration of 100 mg kg(-1) glucose and 0.5 mg kg(-1) indocyanine green solutions, respectively, and calculated by applying a one-compartment model. Three sets of measurements were performed before and after haemorrhage (30 mL kg(-1) and subsequent fluid volume loading (90 mL kg(-1) of lactated Ringer's solution).

RESULTS

A linear correlation was observed between IDVG and ITBV (r2 = 0.52, n = 42, P < 0.001) and between PV-ICG and ITBV (r2 = 0.44, n = 42, P < 0.001) throughout the procedures. A linear correlation was also observed between changes in IDVG and those in ITBV (r2 = 0.76, n = 28, P < 0.001). The ITBV/IDVG ratio during normovolaemia was 0.26 +/- 0.04, which remained unchanged during the procedure.

CONCLUSION

Results showed that that IDVG has a linear correlation with ITBV, and support the concept that IDVG measurement has potential as a surrogate measure of ITBV in various fluid volume states.

A marked decrease in bispectral index with elevation of suppression ratio by cervical haematoma reducing cerebral perfusion pressure

A 77-year-old man with a ruptured abdominal aortic aneurysm undergoing aneurysmectomy were anaesthetised with ketamine under bispectral index (BIS) monitoring, which is a clinical EEG monitor for measurement of depth of anaesthesia/sedation. First marked BIS reduction with elevation of suppression ratio (SR) was observed following severe hypotension by deflation of the aortic occlusion balloon. The re-inflation and rapid blood transfusion improved haemodyanamics and BIS and SR. At second marked BIS reduction with SR elevation, a heavy cervical swelling due to a massive subcutaneous haematoma around the previously mis-punctured right carotid artery extending throughout the whole neck was observed without hypotension. Cervical relief incision improved the BIS and SR. The present case suggests that BIS monitor may be a simple and convenient monitor for cerebral ischaemia detection.

Daily changes of the area of density in the dependent lung region - evaluation using transesophageal echocardiography

OBJECTIVE

To evaluate the daily changes of the area of density using transesophageal echocardiography (TEE) in acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) patients.

DESIGN

Retrospective observational study.

SETTING

General ICU in a university hospital.

PATIENTS

Fifteen patients with ARDS or ALI who underwent TEE examination for more than 5 days.

MEASUREMENTS

Densities in the lower left lung region were observed through the descending aorta by TEE. Daily changes of the area of density were evaluated. The areas of density estimated by TEE were compared with those obtained by computed tomography (CT). The relation between the area of density and PaO(2)/FIO(2)was calculated.

RESULTS

The area of density in the dependent lung region measured by TEE was 11.1+/-5.7 cm(2) (mean +/- SD) at the mid-esophageal position. The area of density in ARDS patients changed daily from 12.0+/-2.8 cm(2) to 8.5+/-6.7 cm(2). The areas of density evaluated using TEE in the left lung correlated significantly with those estimated using CT ( r=0.72, p<0.01). In addition, we found a significant correlation between PaO(2)/FIO(2) and the area of density estimated by TEE ( r=-0.53, p<0.05).

CONCLUSION

Using TEE, we could evaluate daily changes of the area of density in the dependent lung region in the intensive care situation. The areas of density in ARDS patients changed from day to day following the changes of oxygenation.

Haemodynamic comparison of propofol-fentanyl anaesthesia with midazolam-fentanyl anaesthesia in CABG patients without preoperative heart failure

This study was designed to compare prebypass haemodynamics under total intravenous anaesthesia (TIVA) using midazolam-fentanyl (group M) and propofol-fentanyl (group P) combinations. Sixteen adult patients undergoing CABG were studied with patients in group M and P (n = 8 each) given intravenous midazolam 0.1 mg.kg-1.h-1 and propofol 4 mg.kg-1.h-1 with fentanyl 25 micrograms.kg-1 until sternotomy, respectively. Following induction of anaesthesia, cardiac index and heart rate decreased significantly (30% and 20% in both groups, p < 0.05) these variables returned to baseline on completion of sternotomy. In addition, in group P mean arterial pressure decreased significantly (about 15%) following induction and there were no ischaemic signs. Overall for MAP there was no significant difference between the two groups. LVSWI and RVSWI were reduced by around 25% in both groups. Only the change in LVSWI reached statistical significance (p < 0.05). This reduction may have exert a caridioprotectant action by decreasing myocardial oxygen consumption. We conclude that both TIVA techniques represent an acceptable anaesthetic regimen for use in cardiac anaesthesia.

Exposure to cigarette smoke impairs alveolar macrophage functions during halothane and isoflurane anesthesia in rats

BACKGROUND

Smoking alters numerous alveolar macrophage functions and is an important risk factor for postoperative pulmonary complications. The authors therefore tested the hypothesis that smoke exposure impairs antimicrobial and proinflammatory responses in alveolar macrophages during halothane and isoflurane anesthesia with mechanical ventilation.

METHODS

Thirty control rats and 30 rats exposed to cigarette smoke were mechanically ventilated with 1.5 minimum alveolar concentration halothane and isoflurane. Ten smoke-exposed and control animals were assigned to one of three different anesthetic durations (0, 2, and 6 h). The fraction of aggregated cells and cell distribution were determined. Opsonized and unopsonized phagocytosis was measured. Microbicidal activity was determined as the ability to kill Listeria monocytogenes. The expression of interleukin (IL)-1alpha, IL-1beta, IL-6, macrophage inflammatory protein-2, interferon-gamma, and tumor necrosis factor-alpha was measured by semiquantitative reverse-transcription polymerase chain reaction. Pulmonary lavage concentrations of these cytokines were measured by enzyme-linked immunosorbent assay.

RESULTS

During both halothane and isoflurane anesthesia, the fraction of aggregated macrophages increased, whereas unopsonized and opsonized phagocytosis and microbicidal activity decreased significantly over time in both groups. Responses observed in smoke-exposed rats were almost twice as great as those observed in the control rats. Gene expression and production of all proinflammatory cytokines except IL-6 increased 2-20-fold during anesthesia. The increases in IL-1beta, interferon-gamma, and tumor necrosis factor-alpha in the control rats were 1.5-8 times greater than those in the smoke-exposed rats.

CONCLUSION

Antimicrobial and proinflammatory responses of alveolar macrophages during anesthesia were markedly suppressed by smoke exposure. Our data suggest that smoke exposure reduces the efficacy of immune defenses during anesthesia.

[Perioperative management of a patient with cryoglobulinemia for open heart surgery]

A 57-year-old male with cryoglobulinemia underwent an aortic valve replacement for aortic regurgitation under total intravenous anesthesia with droperidol, fentanyl and ketamine in combination with mild hypothermic cardiopulmonary bypass (esophageal temperature = 34 degrees C). Preoperative steroid therapy with prednisolone of daily dose from 40 to 7.5 mg for six months and plasma exchange (3200 ml) on the day before the operation were performed to attenuate the degree of cryoglobulinemia. He showed an uneventful intraoperative course and there was no postoperative complication associated with cryoglobulinemia.

[The volume and pH of gastric fluid in elective surgical patients after preoperative oral fluid intake]

The effect of preoperative oral fluid intake on the volume and pH of gastric fluid was examined in 45 elective surgical patients ranged in ages from 18 to 70 years. Two hours preoperatively they all received oral roxatidine 75 mg with 10 ml water, immediately followed by 150 ml oral water or 150 ml refreshing drink or no fluid as control. Just after the induction of anesthesia, a Salem-sump tube was put down to the stomach to collect gastric fluid in each patient. The volume and pH of gastric fluid taken were 10.9 +/- 7.9 ml, 16.3 +/- 2.3 in control group, 8.0 +/- 6.0 ml, 6.2 +/- 2.4 in the water group and 6.3 +/- 6.0 ml, 7.1 +/- 1.7 in the refreshing drink group. As there were no significant differences in gastric pH values in the three groups, the highest value was found in the refreshing drink group. No significant difference in VAS of hungry and thirsty feeling was found among the three groups. We conclude that preoperative oral water or refreshing drink with roxatidine 75 mg 2 hours before the start of anesthesia may not increase the risk of aspiration during the induction of anesthesia.