In this paper the use of a continuous-wave microwave sensor as a non-contact tool for quantitative measurement of respiratory tidal volume has been evaluated by experimentation in seventeen healthy volunteers. The sensor working principle is reported and several causes that can affect its response are analyzed. A suitable data processing has been devised able to reject the majority of breath measurements taken under non suitable conditions. Furthermore, a relationship between microwave sensor measurements and volume inspired and expired at quiet breathing (tidal volume) has been found.

This study was undertaken to develop an anesthetized dog heatstroke model. Forty-six animals were anesthetized with pentobarbital sodium (25 mg/kg) intravenously, and maintained at an ambient temperature of (42-46 degrees C) with a water-heated blanket over 2.5-3.0 h until rectal temperatures rose to 43.0-44.5 degrees C. Animals then cooled passively until death occurred or until 18 h elapsed, and were prepared for autopsy. Liver, kidney, and brain temperature, mean weighted skin temperature, mean weighted surface heat loss, and metabolic rates were obtained. There were no significant differences between liver, kidney, brain, and rectal temperatures during the heating and cooling periods. Cardiac output rose to 127% of initial value, and dropped rapidly to zero at 43.4 degrees C rectal temperature. The rapid decline was accompanied by a doubling of heart rate and a rapid drop in blood pressure and respiratory rate. Cheyne-Stokes respiration and apnea preceded bradycardia followed by asystole or ventricular fibrillation. Certain serum constituents demonstrated modest elevations suggestive of widespread tissue damage. Autopsy did not reveal a clear pattern of heat injury, with the exception of consistent congestion of the major organs and karyorrhexis of lymphocytes. These data are in agreement with similar data from human heatstroke victims and other heatstroke modeling in dogs, and support the concept that the anesthetized dog can in many respects provide an adequate model for human heatstroke.

Our findings suggest that ASA: 1) is only effective to treat the very transient TxB2-induced pulmonary vasoconstriction resulting in hydrostatic edema, and it is ineffective, even accentuates, the subsequent major pulmonary endothelial cell injury leading to alveolar flooding that is unrelated to TxB2; 2) has a transient protective effect on the TxB2-induced early bronchospasm; 3) has a biphasic behaviour on gas exchange, with a benefit which lasts only one hour and then results in a worse gas exchange; 4) has an immediate, stabilizing, persisting effect on R, contrasting with its transient effect on pulmonary hemodynamics and PaO2.

SummaryBackgroundEndoscopic retrograde cholangiopancreatography ERCP is a painful and long procedure requiring transient deep analgesia and conscious sedation. An ideal anaesthetic that guarantees a rapid and smooth induction, good quality of maintenance, lack of adverse effects and rapid recovery is still lacking.This study aimed to compare safety and efficacy of a continuous infusion of low dose remifentanil plus ketamine combined with propofol in comparison to the standard regimen dose of remifentanil plus propofol continuous infusion during ERCP.Material/Methods322 ASAI-III patients, 18–85 years old and scheduled for planned ERCP were randomized. Exclusion criteria were a predictable difficult airway, drug allergy, and ASA IV–V patients.We evaluated Propofol 1 mg/kg/h plus Remifentanil 0.25 μg/kg/min (GR) vs. Propofol 1 mg/kg/h plus Ketamine 5 μg/kg/min and Remifentanil 0.1 μg/kg/min (GK).Main outcome measures were respiratory depression, nausea/vomiting, quality of intraoperative conditions, and discharge time. P≤0.05 was statistically significant (95% CI).ResultsRespiratory depression was observed in 25 patients in the GR group compared to 9 patients in the GK group (p=0.0035). ERCP was interrupted in 9 cases of GR vs. no cases in GK; patients ventilated without any complication. Mean discharge time was 20±5 min in GK and 35±6 min in GR (p=0.0078) and transfer to the ward delayed because of nausea and vomiting in 30 patients in GR vs. 5 patients in GK (p=0.0024). Quality of intraoperative conditions was rated highly satisfactory in 92% of GK vs. 67% of GR (p=0.028).ConclusionsThe drug combination used in GK confers clinical advantages because it avoids deep sedation, maintains adequate analgesia with conscious sedation, and achieves lower incidence of postprocedural nausea and vomiting with shorter discharge times.

A simple microwave technique for in vivo monitoring of human pulmonary and cardiac activity is here presented. The technique is based on detecting the changes in the modulation envelope of amplitude modulated waves passing through the human body. A simplified human chest model was developed, proving an unambiguous correlation between heart blood filling and microwave transmission through the chest. A prototype system for transmittance measurement was realized at the 868.5-MHz operating frequency, demonstrating the feasibility of a small, lowcost microwave plethysmograph. In vivo measurements showed a good agreement with numerical simulations.