Rare but dangerous adverse effects of propofol and thiopental in intensive care.
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Acidosis↗
Biomedical subjects
C Gonano
Publications and source records attributed to C Gonano.
Effect of newer anaesthetics on duration of stay in postanaesthesia care unit in patients undergoing major abdominal surgery.
Newer anaesthetic agents, such as remifentanil and sevoflurane, are more expensive than conventional anaesthetics, such as isoflurane and fentanyl. However, newer anaesthetics might outweigh their higher acquisition costs by reducing length of stay in the postanaesthesia care unit and thereby reducing personnel costs. We retrospectively investigated the influence of newer anaesthetics on time to eligibility for discharge from the postanaesthesia care unit in consecutive patients undergoing major abdominal surgery. Using a chart review, patients undergoing major abdominal surgery with three different anaesthetic regimens (isoflurane/fentanyl (n = 80), sevofluranelfentanyl (n = 40), and sevoflurane/remifentanil (n = 42)) were compared regarding duration of anaesthesia, surgery, time till extubation, and time to eligibility for discharge from the postanaesthesia care unit. Extubation times were shorter in patients in the sevoflurane/fentanyl and the sevoflurane/remifentanil groups compared to patients in the isoflurane/fentanyl group. Time to eligibility to discharge from the postanaesthesia care unit was similar in isoflurane/fentanyl and sevoflurane/fentanyl group. In the sevoflurane/fentanyl group, time to eligibility for discharge from the unit showed a tendency to be increased (P = 0.08), however these patients were significantly older compared to the other groups. Sevoflurane and remifentanil did not appear to reduce time to eligibility to discharge from the postanaesthesia care unit in our patients undergoing major abdominal surgery compared to isoflurane and fentanyl. This study highlighted the necessity for carefully planned transition from remifentanil to other longer-acting analgesia in our patients.
Abdomen↗
Bioartificial liver based on porcine hepatocyte: in vitro functional assessment.
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Animals↗
Effects of hypothermia on thrombelastography in patients undergoing cardiopulmonary bypass.
Thrombelastography (TEG) correlates with postoperative chest drain output in patients undergoing cardiopulmonary bypass (CPB). In vitro incubation with heparinase allows TEG monitoring during CPB, despite heparin anticoagulation. Hypothermia impairs coagulation, but these effects cannot be assessed by standard coagulation tests performed at 37 degrees C. The aim of this study was to assess the effects of hypothermia on TEG. Therefore, we have compared normothermic and temperature-adapted TEG in 30 patients undergoing CPB. Our data showed significantly impaired reaction time (r), kinetic time (k), and angle alpha (alpha) in temperature-adapted compared with normothermic TEG. Maximum amplitude (MA), reflecting absolute clot strength, was not affected at temperatures of 33-37 degrees C. These findings indicate a decrease in the speed of clot formation, but not absolute deterioration in clot quality. Furthermore, heparinase-modified TEG indicated that there were nine cases in which heparin effects persisted after heparin reversal with protamine, providing a rational guide to protamine therapy.
Adult↗
Endogenous heparin-like substances significantly impair coagulation in patients undergoing orthotopic liver transplantation.
UNLABELLED: Orthotopic liver transplantation (OLT) is associated with severe bleeding, especially after reperfusion of the grafted liver. Heparin released from the liver graft contributes to postreperfusion coagulopathy. Although patients with liver cirrhosis have increased levels of endogenous heparinoids, the role of these substances during liver transplantation is unclear. Therefore, we performed native and heparinase-modified thrombelastography (TEG) in 72 patients undergoing OLT. TEG was performed at skin incision, 10 min before and 10 min after clamping of the vena cava, 10 min before and 10 min after graft perfusion, and at the end of surgery. Heparinase-modified TEG compared with native TEG demonstrated heparin activity. In contrast to other investigations, we found significant heparin effects before reperfusion, although patients received no exogenous heparin. These heparin effects were greater in patients with cirrhosis compared with patients with cancer as the underlying disease leading to OLT. Administration of coagulation factors is the usual treatment of coagulopathies during OLT. The comparison of native versus heparinase-modified TEG can distinguish between heparin activity or coagulation factor deficiency as a cause of bleeding complications and provides a rational approach to the treatment of bleeding during OLT. IMPLICATIONS: Impaired coagulation function, contributed to by heparin or heparin-like substances, is frequently observed after reperfusion of a transplanted liver. This study demonstrates that a heparinase-modified thrombelastography can identify significant heparin effects in the absence of exogenous heparin administration in patients undergoing liver transplantation.
Anticoagulants↗
Anticoagulation with prostaglandin E1 and unfractionated heparin during continuous venovenous hemofiltration.
OBJECTIVE: To determine the effect of two doses of prostaglandin E1 (PGE1, alprostadil) combined with unfractionated heparin on the hemofilter life-span and the coagulation profile during continuous venovenous hemofiltration. DESIGN: Prospective, randomized, controlled trial. SETTING: Intensive care unit at a university-affiliated hospital. PATIENTS: Twenty-four critically ill, mechanically ventilated patients with postoperative acute renal failure who require continuous venovenous hemofiltration. INTERVENTIONS: The patients were anticoagulated with 5 ng/kg/min PGE1 and 6 IU/kg/hr heparin or 20 ng/kg/min PGE1 and 6 IU/kg/hr heparin, injected into the extracorporeal circuit before the hemofilter. MEASUREMENTS AND MAIN RESULTS: The life-span of 43 hemofilters was evaluated. They were used until extracorporeal line pressure exceeded 250 mm Hg, ultrafiltration rate decreased to 16 mL/min, or grossly visible extracorporeal clotting occurred. Blood was sampled from the afferent (prefilter) and efferent (postfilter) lines of the extracorporeal circuit. Platelet counts, in vitro platelet function, plasma concentrations of platelet factor 4, prothrombin fragment F1+2, thrombin-antithrombin complex, routine plasma coagulation tests, and hemodynamic profile were determined before and during hemofiltration. Hemofilter usage was significantly longer in patients anticoagulated with 20 ng/kg/min PGE1 (32 +/- 3 [SEM] hrs) than with 5 ng/kg/min PGE1 (22 +/- 3 hrs). In vitro bleeding parameters were significantly prolonged in postfilter blood in patients receiving 20 ng/kg/min PGE1. Prefilter, there was no antiplatelet activity in either group and platelet counts remained stable. No intra- or intergroup differences in plasma coagulation profile or hemodynamic parameters were detected. CONCLUSION: Extracorporeal administration of PGE1, combined with low-dose heparinization, inhibits platelet reactivity and preserves hemofilter life dose-dependently.
APACHE↗
Point-of-care coagulation monitoring: applications of the thromboelastography.
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Blood Coagulation Disorders↗
Microvascular pressure profile in intact in situ lung.
We measured the microvascular pressure profile in lungs physiologically expanded in the pleural space at functional residual capacity. In 29 anesthetized rabbits a caudal intercostal space was cleared of its external and internal muscles. A small area of endothoracic fascia was surgically thinned, exposing the parietal pleura through which pulmonary vessels were clearly detectable under stereomicroscopic view. Pulmonary microvascular pressure was measured with glass micropipettes connected to a servo-null system. During the pressure measurements the animal was kept apneic and 50% humidified oxygen was delivered in the trachea. Pulmonary arterial and left atrial pressures were 22.3 +/- 1.5 and 1.6 +/- 1.5 (SD) cmH2O, respectively. The segmental pulmonary vascular pressure drop expressed as a percentage of the pulmonary arterial to left atrial pressure was approximately 33% from pulmonary artery to approximately 130-microns-diam arterioles, 4.5% from approximately 130- to approximately 60-microns-diam arterioles, approximately 46% from approximately 60-microns-diam arterioles to approximately 30-microns-diam venules, approximately 9.5% from 30- to 150-microns-diam venules, and approximately 7% for the remaining venous segment. Pulmonary capillary pressure was estimated at approximately 9 cmH2O.
Animals↗
Distribution of diaphragmatic lymphatic lacunae.
The morphology of the submesothelial lymphatic lacunae on the pleural and peritoneal surface over the tendinous and muscular portion of the diaphragm was studied in 10 anesthetized rabbits. The lymphatic network was evidenced by injecting 1 ml of colloidal carbon solution in the pleural (n = 5) or the peritoneal (n = 5) space. After 1 h of spontaneous breathing, the animal was killed and the diaphragm was fixed in situ by injection of approximately 5 ml of fixative in pleural and peritoneal spaces. Then both cavities were opened and the diaphragm was excised and pinned to a support. According to which cavity had received the injection, the peritoneal or the pleural side of the diaphragm was scanned by sequential imaging of the whole surface by use of a video camera connected to a stereomicroscope and to a video monitor. The anatomic design appeared as a network of lacunae running either parallel or perpendicular to the major axis of the tendinous or muscular fibers. The lacunae were more densely distributed on the tendinous peritoneal area than on the pleural one. Scanty lacunae were seen on the muscular regions of both diaphragmatic sides, characterized by large areas without lacunae. The average density of lacunae on tendinous and muscular regions was 6 and 1.7/cm2 for the pleural side and 25 and 3.4/cm2 for the peritoneal side, respectively. The average width of lacunae was 137.9 +/- 1.6 and 108.8 +/- 1.7 microns on the tendinous pleural and the peritoneal side, respectively, and 163 +/- 1.8 microns on the muscular portion of the pleural and peritoneal surfaces.
Animals↗
Distribution of diaphragmatic lymphatic stomata.
In seven anesthetized rabbits we measured the size, shape, and density of lymphatic stomata on the peritoneal and pleural sides of the diaphragm. The diaphragm was fixed in situ and processed for scanning electron microscopy. Results are from 2,902 peritoneal and 3,086 pleural fields (each 1,620 microns 2) randomly chosen from the various specimens. Stomata were seen in 9% of the fields examined, and in 30% of the cases they appeared grouped in clusters with 2-14 stomata/field. Stoma density was 250 +/- 242 and 72 +/- 57 (SD) stomata/mm2 on peritoneal and pleural sides, respectively, and it was similar over the muscular and tendinous portion of the two surfaces. The maximum diameter ranged from less than 1 to approximately 30 microns, with an average value of 1.2 +/- 3.1 micron. The ratio of the maximum to the minimum diameter and the surface area averaged 2 +/- 1.4 and 0.7 +/- 2.4 micron 2, respectively. The maximum and minimum diameter and surface area values followed a lognormal frequency distribution, suggesting that stomata geometry is affected by diaphragmatic tension.
Animals↗
Parenchymal stress affects interstitial and pleural pressures in in situ lung.
After resecting the intercostal muscles and thinning the endothoracic fascia, we micropunctured the lung tissue through the intact pleural space at functional residual capacity (FRC) and at volumes above FRC to evaluate the effect of increasing parenchymal stresses on pulmonary interstitial pressure (Pip). Pip was measured at a depth of approximately 230 microns from the pleural surface, at 50% lung height, in 12 anesthetized paralyzed rabbits oxygenated via a tracheal tube with 50% humidified O2. Pip was -10 +/- 1.5 cmH2O at FRC. At alveolar pressure of 5 and 10 cmH2O, lung volume increased by 8.5 and 19 ml and Pip decreased to -12.4 +/- 1.6 and -12.3 +/- 5 cmH2O, respectively. For the same lung volumes held by decreasing pleural surface pressure to about -5 and -8.5 cmH2O, Pip decreased to -17.4 +/- 1.6 and -23.8 +/- 5 cmH2O, respectively. Because Pip is more negative than pleural pressure, the data suggest that in intact pulmonary interstitium the pressure of the liquid phase is primarily set by the mechanisms controlling interstitial fluid turnover.
Animals↗
Transperitoneal fluid dynamics in rabbit liver.
The peritoneal cavity of 18 anesthetized spontaneously breathing supine rabbits was opened through a midline section. One or two hollow capsules (surface area 0.8 cm2) were glued to the exposed liver surface, filled with whole or 25% diluted plasma, and connected to a transducer and a graduated pipette. Various hydraulic pressures (Pcap) were set in the capsule; at each Pcap the liquid flow per unit surface area (V/S) between the Disse's interstitial space and the capsule was measured from the rate of liquid displacement in the pipette. The slope of the V/S vs. Pcap linear regression was utilized to estimate the hydraulic conductivity of the Glissonian-peritoneal membrane and averaged 5.1 x 10(-3) +/- 4.7 x 10(-3) (SD) ml.h-1.cmH2O-1.cm-2 (n = 25). Hydraulic pressure in the Disse's space (Pd) was measured by closing the capsule against the transducer disconnected from the pipette. At portal and hepatic venous pressures of 7.6 +/- 2.9 and 2.6 +/- 1 cmH2O, respectively, Pd was 2.05 +/- 2 cmH2O. Physiologically, Starling pressure gradients cause fluid transfer from the sinusoids to the Disse's space; transperitoneal fluid filtration only occurs through the liver surface that faces the diaphragm, which corresponds to one-fifth of the total hepatic surface.
Animals↗
Direct measurement of interstitial pulmonary pressure in in situ lung with intact pleural space.
We developed an experimental approach to measure the pulmonary interstitial pressure with the micropuncture technique in in situ lungs with an intact pleural space. Experiments were done in anesthetized paralyzed rabbits that were oxygenated via an endotracheal tube with 50% humidified oxygen and kept in either the supine or the lateral position. A small area of an intercostal space was cleared of the intercostal muscles down to the endothoracic fascia. Subsequently a "pleural window" was opened by stripping the endothoracic fascia over a 0.2-cm2 surface and leaving the parietal pleura (approximately 10 microns thick). Direct micropuncture through the pleural window was performed with 2- to 3-microns-tip pipettes connected to a servo-null pressure-measuring system. We recorded pleural liquid pressure and, after inserting the pipette tip into the lung, we recorded interstitial pressure from subpleural lung tissue. Depth of recording for interstitial pressure averaged 263 +/- 122 (SD) microns. We report data gathered at 26, 53, and 84% lung height (relative to the most dependent portion of the lung). For the three heights, interstitial pressure was -9.8 +/- 3, -10.1 +/- 1.6, and -12.5 +/- 3.7 cmH2O, respectively, whereas the corresponding pleural liquid pressure was -3.4 +/- 0.5, -4.4 +/- 1, and -5.2 +/- 0.3 cmH2O, respectively.
Animals↗