Takasuke Imai

Anaesthesia affects outcome of sepsis in mice

PurposeTo determine whether the survival curves and rates differ between a mutant strain of mice (C3H/HeJ: endotoxin-resistant) and an endotoxin-susceptible strain (C3H/HeN) when severe sepsis (caecal ligation and puncture: CLP) is performed with different anaesthetics (ketamine or varied exposure to halothane).MethodsThe CLP was performed under a randomly chosen anaesthetic method out of inhalation of halothane in oxygen (15 min, 2 hr, or 6 hr) (100, 120, and 103 mice respectively) or a single injection of ketamineim (127 mice) in paired fashion in eight-week-old male mice of each strain. The daily survival rates were compared between the two strains until the 10th day after CLP for each anaesthetic and among the four anaesthetic methods for each strain using multiple comparisons.ResultsThe C3H/HeJ had delayed death relative to the C3H/HeN with every anaesthetic method except a two hours halothane (P < 0.01 at day 1 and day 2–5 in halothane 15 min and 6 hr,P < 0.05 at day 4–6 in ketamine), however, the final survival rates for each method of anaesthesia were the same in the two strains. Regardless of the genetic susceptibility to endotoxin, short exposure to halothane resulted in the most rapid death compared with the other anaesthetic methods (P < 0.05), and two hours halothane showed the best survival.ConclusionEndotoxin susceptibility affected the septic course for each anaesthetic method, and the anaesthetic methods influenced the survival from sepsis in both strains.RésuméObjectifDéterminer si les taux et courbes de survie diffèrent entre deux lignées de souris, une mutante résistante à l’endotoxine (C3H/HeJ) et une souche susceptible à l’endotoxine (C3H/HeN) lorsqu’elles sont soumises à une septicémie sévère, provoquée par la ligature du caecum et sa perforation (CLP), sous différents agents anesthésiques, kétamine ou halothane d’une durée d’exposition variable.MéthodesLa CLP a été pratiquée chez des groupes pairés de souris mâles âgées de 8 semaines provenant de chaque lignée et soumis à une technique anesthésique choisie aléatoirement: anesthésie d’inhalation à l’halothane dans l’oxygène (15 min, 2h, 6h) (100, 120 et 103 souris respectivement) ou injection im unique de kétamine (127 souris). Les taux de survie quotidiens ont été comparés entre les deux lignées de souris jusqu’au 10e jour après CLP pour chacun des anesthésiques et entre les quatre protocoles anesthésiques pour chaque lignée en utilisant des comparaisons multiples.RésultatsLa lignée résistante à l’endotoxine est décédée de façon plus tardive que la lignée susceptible pour tout protocole anesthésique sauf pour l’anesthésie à l’halothane d’une durée de 2 heures (P < 0,01 au jour 1 et jours 2–5 dans les groupes halothane 15 min et 6 heures, etP < 0,05 aux jours 4–6 pour la kétamine); cependant, le taux final de survie a été le même pour chaque technique anesthésique et pour chaque lignée de souris. Indépendamment de la susceptibilité génétique à l’endotoxine, une exposition courte à l’halothane a entraîné les décès les plus rapides par rapport aux autres méthodes (P < 0,05), l’anesthésie de deux heures à l’halothane étant associée à la meilleure survie.ConclusionLa susceptibilité à l’endotoxine a affecté l’évolution de la septicémie pour chaque technique anesthésique, et les techniques anesthésiques ont influencé la survie à la septicémie dans les deux lignées.

Estimation of the degree of acclimatization to high altitude by a rapid and simple physiological examination

The recent expansion in the geographical areas open to human activity has made it desirable to have an objective method to evaluate the degree of high-altitude acclimatization. In this study, we measured the arterial oxygen saturation value at rest and just after exercise in healthy high-altitude trekkers using a transportable pulse oximeter. During a 100-day stay at high altitude (around 4000 m), the degree of arterial hemoglobin saturation measured at rest was relatively stable. However, shortly after arrival at high altitude, even light exercise induced an acute reduction in the degree of arterial hemoglobin saturation; this reduction was ameliorated as the trekkers became acclimatized to the high altitude. Preliminary short trekking to high altitudes does not appear sufficient to induce this response. It is suggested that this rapid and simple physiological examination, the measurement of arterial oxygen saturation value after light exercise, could be a convenient means of estimating the level of high-altitude acclimatization among healthy subjects.

Influence of constant sustained positive airway pressure on right ventricular performance

ObjectiveThe detrimental effect of positive airway pressure on right ventricular (RV) performance is controversial and the aim of this study was to determine the effects of constant positive airway pressure without ventilatory fluctuation on RV performance with the aid of a pulmonary arterial catheter equipped with a rapid response thermistor for measuring RV ejection fraction (RVEF) and RV end-diastolic volume index (RVEDVI).DesignA prospective, clinical study.SettingThe central operating theatre of a university hospital.PatientsNine patients who had major surgery and required right heart catheterization for normal clinical management.Measurements and resultsCold indicator was injected into the RV 4 or 5 times for each airway pressure (0, 10 or 20 cmH2O) which was maintained manually stable for 15 s, and 9 paired data were analyzed by repeated-measures analysis of variance. They are separated into two groups; RVEF at zero airway pressure greater (A group) or less (B group) than 0.4. In A group (7 patients), increasing airway pressures (0 vs 10 vs 20 cmH2O) did not affect RVEF (0.55±0.05 vs 0.54±0.06 vs 0.56±0.04), RVEDVI (69±36 vs 73±29 vs 58±20 ml·m−2), or stroke volume index (SVI: 38±18 vs 40±17 vs 33±13 ml·beat−1 ·m−2); however, in B (2 patients), RVEF (0.35 and 0.38 vs 0.31 and 0.28 vs 0.19 and 0.17) and SVI (35 and 28 vs 32 and 27 vs 27 and 23) decreased, while RVEDVI increased (99 and 73 vs 103 and 97 vs 146 and 132).ConclusionsIn most patients, the changes in RVEF, SVI, and RVEDVI did not occur under constant positive airway pressure, therefore the changes reported in mechanically ventilated patients may not attributable to the extent of positive airway pressure but rather to abrupt increases in airway pressure. There appears, however, to be patients whose RV function is so disturbed that they cannot cope with increased afterloads.

Platelet-activating factor receptor antagonist attenuates endotoxin-induced vascular hyporeactivity in the pithed rat.

The role of platelet activating factor (PAF) and nitric oxide (NO) in the endotoxin-induced hyporeactivity to noradrenaline was studied in the pithed rat. Pressor dose-response curves to noradrenaline (0.01-10 microg/kg, i.v.) were made starting 1 h after the administration of endotoxin (0.5 mg/kg, i.v.) to the rats. Saline was administered to the control rats. The PAF receptor antagonist, TCV-309 (3-bromo-5-[N-phenyl-N-[2-[[2-(1,2,3,4-tetrahydro-2-isoquinolylcarbon yloxy)ethyl]carbamoyl]ethy]carbamoyl]-1-propylpyridinium nitrate, 100 microg/kg, i.v.), or the NO synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA, 30 mg/kg, i.v.), was administered to the endotoxin-treated rats 20 or 10 min before the noradrenaline challenge. L-NMMA reversed endotoxin-induced hyporeactivity completely. TCV-309 produced a significant, but partial attenuation of the hyporeactivity to noradrenaline (P < 0.01). There was still significant hyporeactivity when compared with the control rats (P < 0.01) and the L-NMMA-treated endotoxin-administered rats (P < 0.05). These data suggest that endogenous PAF contributes to the vascular hyporeactivity to noradrenaline induced by endotoxin and that NO plays a major role in the endotoxin-induced hyporeactivity.

Change in plasma endotoxin titres and endotoxin neutralizing activity in the perioperative period

PurposeTo elucidate whether endotoxaemia detected during major surgery was a specific or non-specific reaction.MethodsProspective clinical study in the operating theatre and multidisciplinary intensive care unit in a university hospital. A series of plasma samples was obtained from 21 patients, including eight after cardiopulmonary bypass (CPB), until 48 hr after surgery. The endotoxin titres in these samples were compared by the two chromogenic limulus amebocyte lysate (LAL) assays; one is factor C containing and the other factor G-free, endotoxin-specific test. The endotoxin neutralizing activity of the plasma was determined by adding the endotoxin to the plasma (1,000 pg · ml−1), and by assaying how much the potency of the endotoxin to activate LAL was lost during incubation for 120 min at 37°C.ResultsAlthough endotoxin litres measured using the test including factor G showed a marked elevation during and after surgery, which were 3 ± 5 (4 ± 10), 14 ± 13 (20 ± 17**), 133 ± 13* (46 ± 29*), 89 ± 72* (48 ± 35*), 62 ± 40** (37 ± 29*), 50 ± 54 (39 ± 36) pg · ml−1 in patients with CPB (without CPB), mean ± SD, at 0, 3, 6, 9, 24, and 48 hr after start of surgery (*P < 0.01, **P < 0.05 compared with 0 hr), those measured by the endotoxin-specific test did not show any changes. Plasma neutralized 95% of endotoxin potency after five minutes incubation at 37°C.ConclusionUsing an endotoxin-specific assay, endotoxin could not be deleted in the blood stream during or after major surgery.RésuméObjectifDéterminer si l’endotoxémie décelée pendant une chirurgie majeure constitue une réaction spécifique ou non spécifique.MéthodesÉtude prospective réalisée au bloc opératoire et à l’unité des soins intensifs d’un hôpital universitaire. Une série d’échantillons de plasma a été prélevée chez 21 patients dont huit après une circulation extracorporelle (CEC) jusqu ’à la 48e h après la chirurgie. Les concentrations d’endotoxine déterminées dans ces échantillons ont été comparés grâce à deux épreuves chromogènes au limulus amébocyte lysate (LAL), une contenant du facteur G et l’autre sans facteur G, l’épreuve spécifique pour l’endotoxine. L’activité neutralisante de l’endotoxine par le plasma a été déterminée en additionnant de l’endotoxine au plasma (1 000 pg ml−1), et en estimant l’importance de la perte de puissance de l’endotoxine nécessaire à l’activation du LAL pendant une incubation de 120 min à 37°C.RésultatsBien que les titrages d’endotoxine déterminés par l’épreuve la facteur G aient révélé une élévation importante pendant et après la chirurgie, 3 ± 5 (4 ± 10), 14 ± 13 (20 ± 17**), 133 ± 13* (46 ± 29*), 89 ± 72* (48 ± 35*), 62 ± 40** (37 ± 29*), 50 ± 54 (39 ± 36) pg · ml−1 chez les opérés sous CEC (sans CEC), moyennes ± SD, à 0, 3, 6, 9, 24 et 48 h après le début de la chirurgie (*P < 0,01, **P < 0,05 comparativement à l’heure 0), les titrages déterminés par le test spécifique de l’endotoxine n’ont pas révélé de changement. Le plasma a neutralisé 95% de la puissance de l’endotoxine après cinq minutes d’incubation à 37°C.ConclusionL’endotoxine n’a pas été décelée dans le sang pendant et après une chirurgie majeure.

An unusual cannister defect detected by an airway gas monitor

To the editor: There have been a number of reports of catheter breakage, but none describing detachment of a venous cannula from the hub. We recently experienced such a detachment during acute normovolemic hemodilution. Hemodilution enables collection of autologous blood that helps limit complications from homologous blood transfusion. We cannulate a large vein, such as the external jugular vein, with a Wallace Y-Can catheter and then insert the needle attached to a blood collection bag (NiproC400) into the catheters rubber seal. In this way, we are able to collect more than two bags of blood without repeat venipuncture. An incident occurred in a 51-year-old woman undergoing modified radical hysterectomy for a malignant ovarian tumor. After lumbar epidural block, general anesthesia was initiated with fentanyl and thiamylal. Oral intubation was facilitated with the administration of vecuronium bromide. Anesthesia was maintained with nitrous oxide and isoflurane in oxygen. Acute normovolemic hemodilution was started by collecting a first aliquot of 400 ml of blood through the Y-Can catheter inserted at the left external jugular vein, while lactated Ringers solution was infused through the left radial vein. No difficulty was encountered with this first extraction. However, with the insertion of the needle of the second bag into the catheters rubber seal, there was no backward flow of blood. When the tape covering the puncture site was removed, the cannula portion of the catheter was found to be missing. Palpation of the puncture site revealed that the dislodged fragment was still present. Pressure on the external jugular