Comparison of the single-use Ambu(®) aScope™ 2 vs the conventional fibrescope for tracheal intubation in patients with cervical spine immobilisation by a semirigid collar*.

Fibreoptic intubation remains a key technique for the management of difficult intubation. We randomly compared the second generation single-use Ambu(®) aScope™ 2 videoscope with a standard re-usable flexible intubating fibrescope in 50 tracheal intubations in patients with a difficult airway simulated by a semirigid collar. All patients' tracheas were intubated successfully with the aScope 2 or the re-usable fibrescope. The median (IQR [range]) time to intubate was significantly longer with the aScope 2 70 (55-97 [41?-226]) s vs 50 (40-59 [27-175]) s, p = 0.0003) due to an increased time to see the carina. Quality of vision was significantly lower with the aScope 2 (excellent 24 (48%) vs 49 (98%), p = 0.0001; good 22 (44%) vs 1 (2%), p = 0.0001; poor 4 (8%) vs 0, p = 0.12) but with no difference in the subjective ease to intubate (easy score of 31 (62%) vs 38 (76%), p = 0.19; intermediate 12 (24%) vs 7 (14%), p = 0.31; difficult 7 (14%) vs 5 (5%), p = 0.76). The longer times to intubate and the poorer scores for quality of vision do not support the use of the single-use aScope 2 videoscope as an alternative to the re-usable fibrescope.

An analysis of patients' understanding of 'routine' preoperative blood tests and HIV screening. Is no news really good news?

OBJECTIVES: Many patients may believe that HIV screening is included in routine preoperative work-ups. We examined what proportion of patients undergoing preoperative blood testing believed that they had been tested for HIV. METHODS: All patients hospitalized for elective orthopaedic surgery between January and December 2007 were contacted and asked to participate in a 15-min computer-assisted telephone interview (n = 1330). The primary outcome was to determine which preoperative tests patients believed had been performed from a choice of glucose, clotting, HIV serology and cholesterol, and what percentage of patients interpreted the lack of result communication as a normal or negative test. The proportion of patients agreeable to HIV screening prior to future surgery was also determined. RESULTS: A total of 991 patients (75%) completed the questionnaire. Three hundred and seventy-five of these 991 patients (38%) believed incorrectly that they had been tested for HIV preoperatively. Younger patients were significantly more likely to believe that an HIV test had been performed (mean age 46 vs. 50 years for those who did not believe that an HIV test had been performed; P < 0.0001). Of the patients who believed that a test had been performed but received no result, 96% interpreted lack of a result as a negative HIV test. Over 80% of patients surveyed stated that they would agree to routine HIV screening prior to future surgery. A higher acceptance rate was associated with younger age (mean age 47 years for those who would agree vs. 56 years for those who would not; P < 0.0001) and male sex ( P < 0.009). CONCLUSIONS: Many patients believe that a preoperative blood test routinely screens for HIV. The incorrect assumption that a lack of result communication indicates a negative test may contribute to delays in HIV diagnoses.

Is a pre-anaesthetic information form really useful?

BACKGROUND: All patients should be fully informed about the risks and benefits of anaesthetic procedures before giving a written consent. Moreover, the satisfaction level may vary in proportion to the information given. We aimed to determine, in a single-blind randomized-controlled study, whether an information form given before the pre-anaesthetic consultation could improve perceived information, information gain and satisfaction level. METHODS: Two hundred patients ASA 1-3 scheduled for an elective orthopaedic surgery were randomized into two groups: a group that received an information form before the pre-anaesthetic consultation (IF group) and a control group (no information form). A standardized questionnaire was submitted after the pre-anaesthetic consultation and after the operation. This 17-item questionnaire explored perceived information (five items), information gain (three items) and satisfaction level (nine items). The items of each topic were pooled and compared between groups. RESULTS: One hundred and eighty-five patients (92.5%) completed the study. The IF group had better perceived information (IF group 73% vs. control group 63%, P=0.002), higher information gain (IF group 75% vs. control group 62%, P=0.001) and a higher satisfaction level (IF group 95% vs. control group 92%, P=0.048). CONCLUSIONS: Our study suggests that an information form given before the pre-anaesthetic consultation enhances perceived information, information gain and satisfaction level.

Evaluation of the Video Intubation Unit in morbid obese patients.

BACKGROUND: Tracheal intubation may be more difficult in morbidly obese (MO) patients than in the non-obese. The aim of this study was to evaluate clinically if the use of the Video Intubation Unit (VIU), a video-optical intubation stylet, could improve the laryngoscopic view compared with the standard Macintosh laryngoscope in this specific population. METHODS: We studied 40 MO patients (body mass index >35 kg/m(2)) scheduled for bariatric surgery. Each patient had a conventional laryngoscopy and a VIU inspection. The laryngoscopic grades (LG) using the Cormack and Lehane scoring system were noted and compared. Thereafter, the patients were randomised to be intubated with one of the two techniques. In one group, the patients were intubated with the help of the VIU and in the control group, tracheal intubation was performed conventionally. The duration of intubation, as well as the minimal SpO(2) achieved during the procedure, were measured. RESULTS: Patient characteristics were similar in both groups. Seventeen patients had a direct LG of 2 or 3 (no patient had a grade of 4). Out of these 17 patients, the LG systematically improved with the VIU and always attained grade 1 (P<0.0001). The intubation time was shorter within the VIU group, but did not attain significance. There was no difference in the SpO(2) post-intubation. CONCLUSION: In MO patients, the use of the VIU significantly improves the visualisation of the larynx, thereby improving the intubation conditions.

Evaluation of the GlideScope for tracheal intubation in patients with cervical spine immobilisation by a semi-rigid collar.

Application of cervical collars may reduce cervical spine movements but render tracheal intubation with a standard laryngoscope difficult if not impossible. We hypothesised that despite the presence of a Philadelphia Patriot cervical collar and with the patient's head taped to the trolley, tracheal intubation would be possible in 50 adult patients using the GlideScope and its dedicated stylet. Laryngoscopy was attempted using a Macintosh laryngoscope with a size 4 blade, and the modified Cormack-Lehane grade was scored. Subsequently, laryngoscopy with the GlideScope was graded and followed by tracheal intubation. All patients' tracheas were successfully intubated with the GlideScope. The median (IQR) intubation time was 50 s (43-61 s). The modified Cormack-Lehane grade was 3 or 4 at direct laryngoscopy. It was significantly reduced with the GlideScope (p < 0.0001), reaching grade 2a in most patients. Tracheal intubation in patients wearing a semi-rigid collar and having their head taped to the trolley is possible with the help of the GlideScope.

The use of clays to sequestrate organic pollutants. Leaching experiments.

Leaching experiments are performed from clay-pollutant systems in order to evaluate the capability of clays to sequestrate organic pollutants from wastewaters. Reference kaolinite KGa-1b, montmorrillonite SWy-2 and reference soil BCR-700 are the sorbent materials. 2,4,6-trichloroaniline (2,4,6-TCA) and 4-chlorophenol (4-CP) are the typical pollutants, sorbed at amounts of 10.0 mg g(-1) and 5.8 mg g(-1) on SWy-2 and 7.3 mg g(-1) and 2.2 mg g(-1) on KGa-1b, respectively. The leaching agents are ultrapure water and model solutions of acid rain and surface waters that simulate meteoric leaching. 1.0mM HNO(3), 1.0mM H(2)SO(4) solutions and a methanol/water 50/50 (v/v) mixture simulate leaching agents of industrial source. The results are compared and the preferential capability of the clays to sequestrate the more lipophilic 2,4,6-TCA is evidenced. The bond interactions are discussed and explained through preferential adsorption reactions. For montmorrillonite also a simultaneous intercalation in the phyllosilicate interlayer is proposed.

Photodegradation of E110 and E122 dyes in a commercial aperitif. A high performance liquid chromatography-diode array-tandem mass spectrometry study.

A commercial aperitif containing E110 and E122 dyes is exposed to photo-irradiation in solar box under conditions chosen to simulate sun light irradiation. After 16 days of irradiation the red-coloured aperitif assumes a very pale yellow colour. HPLC-diode array-MS/MS analysis evidences the presence in the commercial aperitif of some impurities with naphthalene-based structures. The structures for the photodegradation products are proposed.

A new hydrophilic interaction liquid chromatography tandem mass spectrometry method for the simultaneous determination of seven biogenic amines in cheese.

An HILIC-PI APCI MS/MS method is developed for the determination of seven biogenic amines (cadaverine, histamine, putrescine, spermidine, spermine, tryptamine and tyramine) in cheese. Their presence and relative amounts give useful information about freshness, level of maturing, quality of storage and cheese typicization. The major drawback in the analysis is represented by the relevant matrix effect and the general unbalanced concentrations of the different amines in cheese. The method proposed represents an improvement with respect to an HPLC-MS/MS method already developed in this laboratory. The new method permits better sensitivities it makes use of a Waters Atlantis HILIC (150.0 mm x 2.1 mm i.d., 3 microm) stationary phase and of a mobile phase of acetonitrile and ammonium formate 50.0 mM in ultrapure water brought to pH 4.00 for formic acid, flowing under gradient conditions. The chromatographic system is interfaced with a 3200QTrap LC-MS/MS system (Applied Biosystem, Foster City, CA, USA) by a Turbo V interface equipped with Heated Nebuliser (APCI) and Turbo Ion Spray (TIS) probes. LOQ values lower than 10 microg L(-1) are obtained. The method is applied in the analysis of Castelmagno cheese.

Videolaryngoscopy improves intubation condition in morbidly obese patients.

BACKGROUND AND OBJECTIVE: Tracheal intubation may be more difficult in morbidly obese patients (body mass index >35 kg m(-2)) than in the non-obese. Recently, new video-assisted intubation devices have been developed. After some experience with videolaryngoscopy, we hypothesized that it could improve the laryngoscopic view in this specific population and therefore facilitate intubation. The aim of this study was to assess the benefit of a videolaryngoscope on the grade of laryngoscopy in morbid obesity. METHODS: We studied 80 morbidly obese patients undergoing bariatric surgery. They were randomly assigned to one of two groups. One group was intubated with the help of the videolaryngoscope and in the control group the screen of the videolaryngoscope was hidden to the intubating anaesthesiologist. The primary end-point of the study was to assess in both groups the Cormack and Lehane direct and indirect grades of laryngoscopy. The duration of intubation, the number of attempts needed as well as the minimal SPO2 reached during the intubation process were measured. RESULTS: Grade of laryngoscopy was significantly lower with the videolaryngoscope compared with the direct vision (P < 0.001). When the grade of laryngoscopy was higher than one with the direct laryngoscopy (n = 30), it was lower in 28 cases with the videolaryngoscope and remained the same only in two cases (P < 0.001). The minimal SPO2 reached during the intubation was higher with the videolaryngoscope but it did not reach statistical significance. CONCLUSIONS: In morbidly obese patients, the use of the videolaryngoscope significantly improves the visualization of the larynx and thereby facilitates intubation.

Molar substitution and C2/C6 ratio of hydroxyethyl starch: influence on blood coagulation.

BACKGROUND: Development of hydroxyethyl starches (HES) with a low impact on blood coagulation but a long intravascular persistence is of clinical interest. A previous in vitro study showed that low substituted high molecular weight HES does not compromise blood coagulation more than medium molecular weight HES. In the present study we assessed the individual effects on blood coagulation of molar substitution and C2/C6 ratio of a high molecular weight HES. METHODS: Blood was obtained from 30 healthy patients undergoing elective surgery and mixed with six high molecular weight (700 kDa) HES solutions differing in their molar substitution (0.42 and 0.51) and C2/C6 ratio (2.7, 7 and 14) to achieve 20, 40 and 60% dilution. Blood coagulation was assessed by Thrombelastograph analysis (TEG) and plasma coagulation tests. Data were compared using a three-way analysis of variance model with repeated measures on the three factors. RESULTS: Higher molar substitution compromised blood coagulation most (for all TEG parameters, P<0.05). The lowest C2/C6 ratio was associated with the lowest effect on blood coagulation; r (P<0.001), angle alpha (P=0.003) and coagulation index (P<0.001). No effect on k and maximum amplitude was observed (P for both >0.50). The higher molar substitution was associated with a lesser increase in PT (P=0.007) and a greater decrease in factor VIII (P=0.010). PTT, functional and antigenic von Willebrand factors were not significantly influenced by molar substitution (P for all >0.20). No significant differences between solutions with the same molar substitution but different C2/C6 ratios were found in plasma coagulation parameters (P for all >0.05). CONCLUSIONS: TEG analysis indicates that high molecular HES with a molar substitution of 0.42 and a C2/C6 ratio of 2.7 has the lowest effect on in vitro human blood coagulation.

HPLC-UV and HPLC-MSn multiresidue determination of amidosulfuron, azimsulfuron, nicosulfuron, rimsulfuron, thifensulfuron methyl, tribenuron methyl and azoxystrobin in surface waters.

The paper presents a new HPLC method, with UV and MS(n) detection, for the determination of seven pesticides, including the sulfonylurea herbicides amidosulfuron, azimsulfuron, nicosulfuron, rimsulfuron, thifensulfuron methyl, tribenuron methyl, and the fungicide azoxystrobin characterised by a methoxyacrilate structure. The methodology consists of a preconcentration/SPE (solid phase extraction) step and HPLC-UV (240 nm detection wavelength)-MS(n) analysis. Under the optimised conditions and after a 1000/1 preconcentration factor, the limits of detection were lower than 14.5 ng L(-1) for UV detection and lower than 8.1 ng L(-1) for MS detection. The limits of quantification were lower than 48.3 ng L(-1) in UV detection and than 26.9 ng L(-1) in MS(n) detection. The analysis of two samples, spiked with a mixture of the pesticides at threshold level concentrations, gave more than 60% recovery.

Antagonism of neuromuscular blockade but not muscle relaxation affects depth of anaesthesia.

BACKGROUND: Conflicting effects of neuromuscular blocking drugs and anticholinesterases on depth of anaesthesia have been reported. Therefore we evaluated the effect of atracurium and neostigmine on bispectral index (BIS) and middle-latency auditory evoked potentials (AAI). METHODS: We studied 40 patients (ASA I-II) aged 18-69 yr. General anaesthesia consisted of propofol and remifentanil by target-controlled infusion and neuromuscular function was monitored by electromyography. When BIS reached stable values, patients were randomly assigned to one of two groups. Group 1 received atracurium 0.4 mg kg(-1) and, 5 min later, the same volume of NaCl 0.9%; group 2 received saline first and then atracurium. When the first twitch of a train of four reached 10% of control intensity, patients were again randomized: one group (N) received neostigmine 0.04 mg kg(-1) and glycopyrrolate 0.01 mg kg(-1), and the control group (G) received only glycopyrrolate. RESULTS: Injection of atracurium or NaCl 0.9% had no effect on BIS or AAI. After neostigmine-glycopyrrolate, BIS and AAI increased significantly (mean maximal change of BIS 7.1 [SD 7.5], P<0.001; mean maximal change of AAI 9.7 [10.5], P<0.001). When glycopyrrolate was injected alone BIS and AAI also increased (mean maximal change of BIS 2.2 [3.4], P=0.008; mean maximal change of AAI 3.5 [5.7], P=0.012), but this increase was significantly less than in group N (P=0.012 for BIS; P=0.027 for AAI). CONCLUSION: These data suggest that neostigmine alters the state of propofol-remifentanil anaesthesia and may enhance recovery.

Molecular weight of hydroxyethyl starch: is there an effect on blood coagulation and pharmacokinetics?

BACKGROUND: The development of hydroxyethyl starches (HES) with low impact on blood coagulation but higher volume effect compared with the currently used HES solutions is of clinical interest. We hypothesized that high molecular weight, low-substituted HES might possess these properties. METHODS: Thirty pigs were infused with three different HES solutions (20 ml kg(-1)) with the same degree of molar substitution (0.42) but different molecular weights (130, 500 and 900 kDa). Serial blood samples were taken over 24 h and blood coagulation was assessed by Thromboelastograph analysis and analysis of plasma coagulation. In addition, plasma concentration and in vivo molecular weight were determined and pharmacokinetic data were computed based on a two-compartment model. RESULTS: Thromboelastograph analysis and plasma coagulation tests did not reveal a more pronounced alteration of blood coagulation with HES 500 and HES 900 compared with HES 130. In contrast, HES 500 and HES 900 had a greater area under the plasma concentration-time curve [1542 (142) g min litre(-1), P<0.001, 1701 (321) g min litre(-1), P<0.001] than HES 130 [1156 (223) g min litre(-1)] and alpha half life (t(alpha)(1/2)) was longer for HES 500 [53.8 (8.6) min, P<0.01] and HES 900 [57.1 (12.3) min, P<0.01] than for HES 130 [39.9 (10.7) min]. Beta half life (t(beta)(1/2)), however, was similar for all three types of HES [from 332 (100) to 381 (63) min]. CONCLUSIONS: In low-substituted HES, molecular weight is not a key factor in compromising blood coagulation. The longer initial intravascular persistence of high molecular weight low-substituted HES might result in a longer lasting volume effect.

Morbid obesity and postoperative pulmonary atelectasis: an underestimated problem.

UNLABELLED: Perturbation of respiratory mechanics produced by general anesthesia and surgery is more pronounced in morbidly obese (MO) patients. Because general anesthesia induces pulmonary atelectasis in nonobese patients, we hypothesized that atelectasis formation would be particularly significant in MO patients. We investigated the importance and resorption of atelectasis after general anesthesia in MO and nonobese patients. Twenty MO patients were anesthetized for laparoscopic gastroplasty and 10 nonobese patients for laparoscopic cholecystectomy. We assessed pulmonary atelectasis by computed tomography at three different periods: before the induction of general anesthesia, immediately after tracheal extubation, and 24 h later. Already before the induction of anesthesia, MO patients had more atelectasis, expressed in the percentage of the total lung area, than nonobese patients (2.1% versus 1.0%, respectively; P < 0.01). After tracheal extubation, atelectasis had increased in both groups but remained significantly more so in the MO group (7.6% for MO patients versus 2.8% for the nonobese; P < 0.05). Twenty-four hours later, the amount of atelectasis remained unchanged in the MO patients, but we observed a complete resorption in nonobese patients (9.7% versus 1.9%, respectively; P < 0.01). General anesthesia in MO patients generated much more atelectasis than in nonobese patients. Moreover, atelectasis remained unchanged for at least 24 h in MO patients, whereas atelectasis disappeared in the nonobese. IMPLICATIONS: We compared the resolution over time of pulmonary atelectasis after a laparoscopic procedure by performing computed tomography scans in two different groups of patients: 1 group had 10 nonobese patients, and in the other group there were 20 morbidly obese patients.

An animal model of response and nonresponse to inhaled nitric oxide in endotoxin-induced lung injury.

STUDY OBJECTIVE: Oxygenation may be improved in 40 to 60% of ARDS patients by inhalation of nitric oxide (NO). We have studied the response to inhaled NO in porcine acute lung injury 4 h and 6 h after onset of a 2-h endotoxin infusion (30 microg/kg/h), hypothesizing that a responder may change to a nonresponder over time and with progression of lung injury. DESIGN: Animal study. SETTING: Experimental laboratory in a university hospital. INTERVENTIONS AND MEASUREMENTS: We studied eight pigs under general anesthesia (mean weight, 26.2 kg) receiving mechanical ventilation adjusted to normocapnia, with a fraction of inspired oxygen (FIO(2)) of 0.5 to 1.0. Blood gases, endotoxin concentration, and central hemodynamics were measured hourly, and ventilation-perfusion (/) relationships were assessed by multiple inert gas elimination technique before and after inhalation of NO. NO was delivered at 40 ppm for 10 min at 4 h and 6 h of endotoxin exposure. RESULTS: Seven of eight pigs were responders to NO at 4 h, defined as a > or = 20% increase in oxygenation index (PaO(2)/FIO(2)) [223 +/- 43 to 330 +/- 56 mm Hg; p = 0.001]. The same pigs exhibited a > or = 20% fall in mean pulmonary artery pressure (39.4 +/- 2.2 to 30.0 +/- 2.1 mm Hg; p < 0.001). The response correlated to the perfusion to "normal /" regions (r = - 0.82) and negatively to shunt and dead space ventilation (r = 0.76 and r = 0.87, respectively). At 6 h, seven of eight pigs were nonresponders, despite unaltered hemodynamics and gas exchange. Correlations at 4 h between physiologic variables and response to NO were abolished. The logarithmic SDs of the perfusion distribution, a measure of the degree of / mismatch, increased significantly from 4 to 6 h (p = 0.04). CONCLUSION: Response to inhaled NO is abolished over time in endotoxin-induced ARDS pig lungs. The response seems to be related to the degree of / mismatch, which may indicate an important role of hypoxic pulmonary vasoconstriction.

Impact of a bicarbonated saline solution on early resuscitation after major burns.

OBJECTIVE: The study aimed at assessing the impact of the introduction of a bicarbonated saline solution on total fluid load, weight gain and acid base status during acute burn resuscitation. DESIGN: Based on a retrospective patient record review. SETTING: Burn care centre of a surgical ICU in a tertiary university hospital. PATIENTS: Two groups of adult patients (20/20), with thermal burns of 25% or more body surface area were studied. INTERVENTION: Modification of the resuscitation fluid composition from lactated Ringer's solution (LR: Na 132 mmol/l, Cl 112 mmol/l, 263 mosm/l), to bicarbonated 0.9% saline (BS: Na 180 mmol/l, Cl 154 mmol/l, 340 mosm/l) METHODS: Age, weight, burn size and depth, inhalation injury, fluid intakes over 48 h post-injury, plasma sodium, chloride, creatinine, albumin levels, blood gases and ventilation support were recorded. RESULTS: The demographic characteristics of the patients (41 +/- 16 years) in the two groups were not different, with severe burns involving 44 +/- 17% body surface area. While the total fluid volumes administered did not differ, BS was associated with lower plasma pH, base excess and bicarbonate levels for 24 h and with hyperchloraemia. Clinical evolution did not differ. CONCLUSIONS: Using bicarbonated saline solution for resuscitation causes a transient hyperchloraemic dilutional acidosis compared with LR, and has no other detectable clinical impact over the first 10 days after severe burn injury.

Benefits of endoscopic vein harvesting.

The purpose of this study was to evaluate and compare the benefits of endoscopic saphenous vein harvesting (EVH) with the traditional incision technique (TIT) for coronary artery bypass grafting (CABG) in respect to the technical procedure and clinical outcome. In a prospective nonrandomized, case-matched study the greater saphenous vein was harvested for CABG in 22 patients using the endoscopic technique and in 18 patients with the traditional method. Comparisons were made for the operating time, length of incision and vein harvested, graft quality, postoperative complications, and pain assessment. Patient demographics were well matched. EVH required smaller incisions than did the TIT (10.5 +/- 6.6 vs. 31.2 +/- 7.8 cm, respectively; p < 0.0001). Harvest time and vein quality were comparable in the two groups. Total vein operating time was shorter following the endoscopic technique (60 +/- 24 vs. 100 +/- 35 minutes, respectively; p < 0.0001). EVH had fewer complications (NS), and postoperative pain was significantly less (p = 0.0034). The major advantages of endoscopic vein harvesting are a significant reduction of postoperative pain and strikingly better cosmetic results. Wound complications seem to be less frequent.

Segmental bioelectrical impedance analysis to assess perioperative fluid changes.

OBJECTIVES: Perioperative fluid accumulation determination is a challenge for the clinician. Bioelectrical impedance analysis (BIA) is a noninvasive method based on the electrical properties of tissues, which can assess body fluid compartments. The study aimed at assessing their changes in three types of surgery (thoracic, abdominal, and intracranial) requiring various regimens of fluid administration. DESIGN: Prospective descriptive trial. PATIENTS: A total of 26 patients scheduled for elective surgery were separated into three groups according to site of surgery: thoracic (n = 8), abdominal aortic (n = 8), and brain surgery (n = 10). SETTING: University teaching hospital. INTERVENTION: None. MEASUREMENTS: Whole body, segmental (arm, trunk, and legs) BIA at multiple frequency (0.5, 50, 100 kHz) was used to assess perioperative fluid accumulation after surgery. The fluid balances were calculated from the charts. RESULTS: The patients were aged 62+/-4 yrs. Fluid balances were 4.8+/-1.0 L, 4.1+/-0.5 L, and 1.9+/-0.3 L, respectively, in the three groups. In trunk surgery patients, fluid accumulation was detected as a drop in impedance in the operated area at all frequencies. In the operated area, there was an expansion of both intra- and extracellular compartments. A reduction in high frequencies' impedance in the legs was only detected after aortic surgery. Fluid accumulation and trunk impedance changes were strongly correlated. Neurosurgery only induced minor body fluid changes. CONCLUSIONS: Segmental BIA is able to detect and localize perioperative fluid accumulation. It may become a bedside tool to quantify and to localize fluid accumulation.

Effects of norepinephrine on the distribution of intestinal blood flow and tissue adenosine triphosphate content in endotoxic shock.

OBJECTIVE: To investigate, during endotoxic shock, the effect of a treatment of norepinephrine (NE) administration on the distribution of blood flow and adenosine triphosphate (ATP) content in the intestinal wall. DESIGN: Randomized controlled trial. SETTING: Animal laboratory. SUBJECTS: Domestic pigs. INTERVENTION: A total of 18 pigs were anesthetized with ketamine and pentobarbital, mechanically ventilated, hemodynamically monitored, and then challenged with a continuous infusion of Escherichia coli endotoxin (ET) (15 microg/kg) for 2 hrs. Three groups of six animals were studied; one served as time control, one group received ET and fluid resuscitation, and a third group received ET, fluid resuscitation, and a perfusion of NE to maintain constant mean arterial pressure (MAP). MEASUREMENTS AND MAIN RESULTS: Cardiac output, mesenteric arterial blood flow, MAP, pulmonary pressure, and portal pressure were measured. Intestinal mucosal intracellular pH (pHi) was determined with saline-filled balloon tonometers. Tissue blood flows to the intestinal mucosa and to the muscular layer were independently measured with fluorescent microspheres, using the arterial reference sample method. Measurements were performed before and 3 hrs after the start of the ET challenge. At the end of the experiments, muscularis and mucosal samples were quickly frozen for further enzymatic ATP measurements. ET administration with fluid resuscitation induced a distributive shock with increased mucosal blood flow and decreased muscularis blood flow, whereas pHi decreased and mucosal ATP content was significantly lower than in the control group. In the group receiving ET plus NE, MAP remained constant, mucosal blood flow did not increase, and mucosal ATP content was equal to the time control group. Meanwhile, mucosal acidosis was not prevented. CONCLUSIONS: Normodynamic endotoxic shock may induce an alteration in mucosal oxygenation, despite an increased tissue blood flow. A treatment of NE combined with fluid resuscitation has complex effects on tissue blood flow, ATP content, and pHi.

In vivo whole-body resting energy expenditure and insulin action in human malignant hyperthermia.

BACKGROUND: Malignant hyperthermia (MH) is a pharmacogenetic disease triggered by volatile anesthetics or succinylcholine. The disorder is heterogenetic and caused by abnormal calcium regulation within skeletal muscle cells. No clear metabolic differences have been found in MH-susceptible (MHS) persons in vivo while not having MH episodes, but some reported signs suggest that insulin action and energy turnover might be altered in muscle of MHS persons. METHODS: In fasting and insulin-stimulated conditions, using the glucose clamp technique and indirect calorimetry, we assessed in vivo resting energy expenditure (REE) and nutrient utilization rates in 10 MHS, 5 MH-equivocal (MHE) and 10 MH-negative (MHN) persons from 14 families. With a model using the persons' fat-free mass, fat mass, age, and gender, we calculated their predicted REE and compared it with measured REE in 10 MHS and 10 MHN persons (measured - predicted = residual REE). RESULTS: In vivo measured REE and glucose disposal rates were similar in 10 MHS and 10 MHN persons. Only during insulin stimulation was residual REE greater in MHS persons (6.4%; P = 0. 013). CONCLUSIONS: In vivo insulin action is unimpaired in MHS persons. Although the absolute values of whole-body REE are the same in MHS and MHN persons, the part of REE independent of the determinants fat-free mass, fat mass, age, and gender is moderately greater in MHS than in MHN persons during insulin exposure. This suggests that MH susceptibility might influence insulin-stimulated energy turnover in muscle.