Surface parasitism by Mycoplasma pneumoniae of respiratory epithelium

Identification of the attachment factor on virulent Mycoplasma pneumoniae organisms which permits surface parasitism of respiratory epithelium was attempted. Brief pretreatment of M. pneumoniae monolayers with protease prevented mycoplasma attachment ot sensitive host cells without reducing viability of the microorganisms. Gel electrophoretic analysis of mycoplasma proteins before and after exposure of intact mycoplasmas to protease revealed the absence of a major protein species (P1) in enzyme-treated preparations while other protein bands with the exception of P2 were virtually unaffected. The absence of P1 correlated with the failure of enzyme-treated mycoplasmas to attach to tracheal explants. P1 regeneration after protease treatment of mycoplasma monolayers was directly associated with reattachment capabilities in M. pneumoniae. Erythromycin inhibited P1 resynthesis, thus preventing resumed attachment activity by mycoplasmas. Lactoperoxidase-catalyzed iodination of intact M. pneumoniae organisms further confirmed that P1 was an external membrane protein and suggested that his surface component was required for the successful membrane-membrane interaction between host and parasite.     

A new model for health effects of air pollutants: evidence for synergistic effects of mixtures of ozone and sulfuric acid aerosols on rat lungs

Chronic respiratory disease-free rats were exposed to relatively low levels of ozone (0.4 to 0.5 ppm) and H2SO4 aerosols (11 to 3,000 microgram/m3) and to mixtures of these pollutants. We independently evaluated exposure effects on conducting airway metabolism as rate of secretion of mucus glycoproteins by tracheal explants and on lung homogenates (predominantly lung parenchyma) by various chemical assays. True synergism was observed in that the response to the mixture of gases exceeded the sum of effects observed with the same concentration of either gas alone. Wet to dry weight ratios; DNA, protein, and RNA content; and the activities various lysosomal hydrolases in the lung homogenate all increased upon exposure to O3-H2-SO4 mixtures concomitant with observed increases in the rate of secretion of mucus glycoproteins by tracheal explants from the same rats. Preliminary experiments suggest that all of these effects are reversible when rats are allowed to recover after exposure. We conclude that the lack of toxicity noted upon exposure of experimental animals to individual pollutant gases at near-ambient levels should be interpreted with caution, since there is now epidemiological, physiological, and biochemical evidence that mixtures of pollutant gases may show synergistic effects.     

An examination of the ability of d-tubocurarine to evoke contraction and mediator release from superfused trachea and parenchymal strips isolated from the guinea pig

The relationship between curare-induced mediator release and contraction in superfused guinea pig trachea and parenchymal strips was examined. In trachea, curare produced histamine release and contraction with peak release occurring in the first 90 sec (collection period 1) after challenge. Peak contraction developed later (collection periods 4-6). Curare-induced contraction of parenchymal strips was inconsistent and smaller than that found in trachea. No histamine could be detected in parenchymal strip superfusate samples. Curare also was selective in releasing histamine from monodispersed airway cells vs. peripheral lung cells. No leukotriene bioactivity or immunoreactivity could be detected after curare challenge of tissues or cell suspensions. Tracheal contractions, but not histamine release, occurring early (first 5 or 6 collection periods) after challenge were antagonized by mepyramine, 10(-6) M, and phenoxybenzamine, 3 X 10(-5) M. Combination of FPL55712, 10(-5) M, with mepyramine did not further alter tracheal contraction. Contractions occurring later after challenge and total histamine release were enhanced by indomethacin, 5 X 10(-6) M. Indomethacin also increased contractions in the presence of mepyramine. With mepyramine and indomethacin, LY171883, 1 and 3 X 10(-6) M, and nordihydroguaiaretic acid, 3 X 10(-5) M, antagonized tracheal contractions to curare, 3 X 10(-3) M, but not to 1 X 10(-3) M, without altering histamine release. Indomethacin prolonged return to base line of tracheal tension after challenge with exogenous histamine. After addition of LY171883 or nordihydroguaiaretic acid, the return of tracheal tension after histamine was not different from that seen without drug pretreatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of ceftazidime in experimental Klebsiella pneumoniae pneumonia: comparison with other antibiotics and measurement of its penetration into respiratory tissues and secretions

The activity of ceftazidime was examined in a murine model of Klebsiella pneumoniae pneumonia in which the antibiotic was administered subcutaneously 6 h after intranasal infection and then twice daily for the next three days (i.e. seven doses). In a series of experiments using this test, the dose of ceftazidime giving 50% survival relative to controls (SD50) ranged from 1.0-9.0 mg/kg/dose while the dose required to reduce the log10 cfu/lung by 50% (CD50) ranged from 24-64 mg/kg/dose. Ceftazidime was considerably more effective than cefotiam, amoxycillin-clavulanic acid or kanamycin in the test. Pharmacokinetic studies with ceftazidime showed that no differences in respiratory tract penetration existed between uninfected mice and mice infected for 48 h with K. pneumoniae. The percentage penetration of ceftazidime from serum was 73% for pleural fluid, 44% for tracheal fluid, 27% for tracheal wall tissue and 17% for whole lung tissue after a subcutaneous injection of 100 mg/kg. At this dose, ceftazidime remained at supra-MIC concentrations for 2-3 h in all compartments examined.     

DISCOPO内镜与McCoy喉镜在困难气道 清醒气管插管中的应用比较*

目的观察DISCOPO内镜与McCoy喉镜在困难气道清醒气管插管中的临床应用效果。方法将符合困难气道诊断标准的择期全麻下手术患者60例随机分为DISCOPO内镜组(D组)和McCoy喉镜组(M组),每组各30例,两组患者在表面麻醉与右美托咪定镇静的基础上,M组运用McCoy喉镜进行气管插管,D组使用DISCOPO内镜进行气管插管,记录两组患者气管插管所用时间、一次性气管插管成功率,声门暴露分级、插管并发症发生情况和围插管期血流动力学[血压(BP)和心率(HR)]变化。结果 D组气管插管时间短于M组(P 0.05),一次性插管成功率及声门暴露良好率明显高于M组(P 0.05),并发症发生率明显低于M组(P 0.05),D组T_2和T_3时间点BP和HR明显低于M组(P 0.05)。结论 DISCOPO内镜用于困难气道清醒插管用时短,成功率高,并发症少,值得临床推广应用。     

Airtraq喉镜与Macintosh喉镜临床应用的比较

目的比较Airtraq喉镜和Macintosh喉镜经口气管插管的临床效果和插管对血流动力学的影响。方法 90例ASAⅠ或Ⅱ级、实施择期整形外科手术的患者,随机分为Airtraq喉镜组(n=45)和Macintosh喉镜组(n=45),常规麻醉诱导后分别采用Airtraq喉镜和Macintosh喉镜进行气管插管操作,观察记录两组的声门暴露情况、插管时间、插管成功率以及并发症的发生情况;并记录麻醉诱导前、诱导后、气管插管时以及插管后1 min、3 min和5 min的收缩压(SBP)、舒张压(DBP)、心率(HR)和心率-收缩压乘积(RPP)的变化。结果 Airtraq喉镜组的声门暴露均为Cormack-Lehane I级,Macintosh喉镜组则有5例Ⅱ级,1例Ⅲ级;Airtraq喉镜组和Macintosh喉镜组的插管一次、二次插管成功率分别是95.6%、86.7%和100%、97.8%;Airtraq喉镜组暴露会厌时间和插管总时间均显著长于Macintosh喉镜组(P<0.05)分别为14.4±6.5 s、32.7±12.3 s和7.7±3.6 s、24.9±6.3 s;与麻醉诱导前相比,两组诱导后的各项血流动力学指标较诱导前均明显下降(P<0.05);与麻醉诱导后相比,Airtraq喉镜组插管时及插管后各时点血流动力学指标无显著性变化(P>0.05),Macintosh喉镜组的HR和RPP则显著升高(P<0.05),组间比较有统计学意义。结论与Macintosh喉镜相比,应用Airtraq喉镜插管可以改善声门的暴露情况、提高气管插管的一次成功率、减轻气管插管的血流动力学变化,但气管插管时间明显延长。     

Pain related to tracheal suctioning in awake acutely and critically ill adults: a descriptive study.

The purpose of this secondary data analysis of findings from a larger procedural pain study was to examine several factors related to pain during tracheal suctioning. In addition to tracheal suctioning, other procedures studied included turning, wound drain removal, femoral catheter removal, placement of a central venous catheter, and wound dressing change. A total of 755 patients underwent the tracheal suctioning procedure that was performed primarily in intensive care units (93%). A 0-10 numeric rating scale, a behavioural observation tool, and a modified McGill Pain Questionnaire-Short Form were used for pain assessment. Pain intensity scores were significantly greater during the tracheal suctioning procedure (M=3.96, S.D.=3.3) than prior to (M=2.14, S.D.=2.8) or after (M=1.98, S.D.=2.7) tracheal suctioning. Few patients received analgesics prior to or during the procedure. Surgical, younger, and non-white patients reported higher pain intensities. Although mean pain intensity during tracheal suctioning was mild, almost the half of the patients reported moderate-to-severe pain. Individualized pain management must be performed by healthcare providers in order to respond to patients' needs as they undergo painful procedures such as tracheal suctioning.     

Global transcriptome analysis of the responses of a fluoroquinolone-resistant Streptococcus pneumoniae mutant and its parent to ciprofloxacin

Streptococcus pneumoniae M22 is a multidrug-resistant mutant selected after exposure of capsulated wild-type S. pneumoniae NCTC 7465 (strain M4) to ciprofloxacin. DNA microarray analysis comparing the gene expression profiles of strain M22 with those of strain M4 showed that strain M22 constitutively expressed 22 genes at levels higher than those observed in strain M4 under all conditions studied. These included the genes encoding the enzymes involved in branched-chain amino acid biosynthesis and two genes (patA and patB) with sequences suggestive of ABC transporter proteins. Expression of the patA and patB genes was induced by ciprofloxacin in both strains, but in strain M4 it only reached the levels observed in strain M22 after long incubation with high concentrations of ciprofloxacin. The altered expression profile observed with strain M22 suggested that the mutation or mutations acquired during resistance selection bring the cell into a state in which the expression of critical genes is preemptively altered to correct for the potential effects of ciprofloxacin on gene expression in the parent strain.     

Transition mutations in the 23S rRNA of erythromycin-resistant isolates of Mycoplasma pneumoniae.

Erythromycin is the drug of choice for treatment of Mycoplasma pneumoniae infections due to its susceptibility to low levels of this antibiotic. After exposure of susceptible strains to erythromycin in vitro and in vivo, mutants resistant to erythromycin and other macrolides were isolated. Their phenotypes have been characterized, but the genetic basis for resistance has never been determined. We isolated two resistant mutants (M129-ER1 and M129-ER2) by growing M. pneumoniae M129 on agar containing different amounts of erythromycin. In broth dilution tests both strains displayed resistance to high levels of several macrolide-lincosamide-streptogramin B (MLS) antibiotics. In binding studies, ribosomes isolated from the resistant strains exhibited significantly lower affinity for [14C]erythromycin than did ribosomes from the M129 parent strain. Sequencing of DNA amplified from the region of the 2S rRNA gene encoding domain V revealed an A-to-G transition in the central loop at position 2063 of M129-ER1 and a similar A-to-G transition at position 2064 in M129-ER2. Transitions at homologous locations in the 23S rRNA from other organisms have been shown to result in resistance to MLS antibiotics. Thus, MLS-like resistance can occur in M. pneumoniae as the result of point mutations in the 23S rRNA gene which reduce the affinity of these antibiotics for the ribosome. Since they involve only single-base changes, development of resistance to erythromycin in vivo by these mechanisms could be relatively frequent event.     

Phosphatidylinositol response to cholinergic agonists in airway smooth muscle: relationship to contraction and muscarinic receptor occupancy

Hydrolysis of membrane phosphatidylinositol (PI) and polyphosphonoinositides (PPI) may be the coupling mechanism between receptor stimulation and the rise in intracellular calcium concentration that leads to smooth muscle contraction. In bovine tracheal smooth muscle, we correlated PI/PPI turnover, contraction and muscarinic receptor occupancy by carbamoylcholine (10(-9) to 10(-2) M). Inositol monophosphate formation after agonist stimulation, in the presence of lithium, provided a direct measurement of PI/PPI breakdown, and receptor occupancy was determined by [3H]quinuclidinyl benzylate binding. Carbamoylcholine caused a concentration-dependent contraction (EC50 = 7.4 X 10(-8) M), PI/PPI response (EC50 = 3.8 X 10(-5) M) and [3H]quinuclidinyl benzylate displacement (with high and low affinity binding sites have dissociation constants (Kd) of 3 X 10(-7) and 6 X 10(-4) M, respectively). This indicates the presence of spare receptors as maximal contraction is obtained when less than 20% of receptors are occupied. The concentration of carbamoylcholine inhibiting 50% of the PI/PPI response and 50% of maximal receptor occupancy (IC50) were similar for atropine (IC50 = 1 X 10(-9) and 5.3 X 10(-9) M, respectively), and for pirenzepine (IC50 = 3 X 10(-6) and 2.3 X 10(-6) M, respectively); the pA2 of the contraction was 8.3 +/- 0.12 for atropine and 7.2 +/- 0.08 for pirenzepine, indicating that M2 receptors may be largely predominant among bovine tracheal smooth muscle muscarinic receptors. Bovine tracheal smooth muscle may be a useful model to study the effects of other spasmogens, as it allows comparison of functional effects, PI breakdown and receptor occupancy in the same preparation.     

Enhanced prostaglandin synthesis after ultraviolet injury is mediated by endogenous histamine stimulation. A mechanism for irradiation erythema.

Acute ultraviolet light B (UVB) injury is associated with dermal mast cell histamine release. The possibility that histamine-stimulated prostaglandin (PG) synthesis could be a mechanism for irradiation erythema was therefore examined using human skin explants. Explants responded to UV irradiation (120 mJ/cm2) with a fivefold increase in synthesis of prostaglandins E2, F2 alpha and 6-keto PGF1 alpha. Incubating explants with the H1 antihistamines brompheniramine (50 microM) or pyrilamine (30 microM) inhibited PG release from irradiated explants 63 +/- 4.9% (mean +/- SEM) 6 h after UV exposure. Antihistamines did not affect PG synthesis in control explants. Irradiation increased the histamine concentration in explant conditioned medium only 50% over basal values, suggesting that irradiation enhanced histamine responsiveness. Explants were therefore incubated with exogenous histamine. In irradiated explants, PG synthesis was stimulated threefold by 3 microM histamine. Unirradiated explants' PG synthesis was unaffected by histamine. Enhanced histamine sensitivity was also examined in epidermal cell cultures. In irradiated cultures, histamine sensitivity was again markedly potentiated: as little as 1 microM histamine stimulated significant PGE2 release and the response to 10-30 microM histamine was increased six to eight times compared with that of unirradiated cultures. These studies demonstrate that endogenous histamine stimulates PG synthesis in human skin after UV injury by potentiation of histamine-induced prostaglandin release. Potentiated agonist responses induced by UV exposure may contribute to the effects of UVB irradiation injury and in particular to irradiation erythema.     

Tracheal colonisation within 24 h of intubation in patients with head trauma: risk factor for developing early-onset ventilator-associated pneumonia

OBJECTIVE: To investigate if tracheal colonisation within 24 h of intubation is a risk factor for developing early-onset ventilator-associated pneumonia (EP) in patients with head trauma. DESIGN: A prospective study in an intensive care unit of a university hospital. POPULATION: One hundred intubated patients were included with head trauma and Glasgow coma score at admission < or =12. METHODS: We took tracheal aspirate samples within 24 h of intubation and performed a protected bronchoalveolar mini-lavage when clinical diagnosis of pneumonia was made. MEASUREMENTS AND RESULTS: On admission time 68 patients (68%) were colonised in trachea, 22 patients were colonised by Staphylococcus aureus, 20 by Haemophilus influenzae, six by Streptococcus pneumoniae and 20 by gram-negative bacilli. The incidence of EP was 26%, and the microorganisms involved were Staph. aureus (44%), H. influenzae (31%), Strep. pneumoniae (12%), and gram-negative bacilli (13%). A multivariate logistic regression analysis showed that the tracheal colonization by Staph. aureus, H. influenzae or Strep. pneumoniae within 24 h of intubation was an independent risk factor for developing EP (odds ratio: 28.9; 95% confidence interval: 1.59-52.5). CONCLUSION: Colonisation of the trachea within 24 h of intubation by Staphylococcus aureus, Haemophilus influenzae or Streptococcus pneumoniae is a risk factor for developing EP in patients with head trauma.     

Post-antibiotic effect of three quinolones against gram negative isolates from urine

The post-antibiotic effect (PAE) is defined as the bacterial growth suppression which persists after a limited exposure to an antimicrobial agent. The PAE and the bactericidal effect of the quinolones ciprofloxacin, norfloxacin and nalidixic acid have been studied against several urinary isolates of Gram-negative bacteria. The PAE was determined after one hour's exposure to the antimicrobial agent using an initial inoculum of 10(5) to 10(6) cfu/ml; the drug was rapidly removed by a 10(-2) dilution technique in antibiotic-free medium. When ciprofloxacin was used at four times its MIC the PAEs were 1.37 +/- 0.09; 2.45 +/- 0.63 and 2.86 +/- 0.15 h against Esch. coli, Klebs. pneumoniae and Pseudomonas aeruginosa, respectively. We found lower values for norfloxacin under the same conditions, and nalidixic acid did not induce a significative PAE. These results could support changes in dosing intervals of norfloxacin and ciprofloxacin, with possibly greater intervals between doses.     

Effects of carbocysteine on antigen-induced increases in cough sensitivity and bronchial responsiveness in guinea pigs

Carbocysteine is a mucoactive drug and is being used for both acute and chronic infectious airway diseases. Although carbocysteine can repair the damage of epithelial cells caused by exposure to various agents, the effects of this agent on allergic airway diseases such as asthma and eosinophilic bronchitis with an isolated chronic cough, in both of which epithelial damage may be characteristic, is not clear. We investigated the effects of carbocysteine on antigen-induced cough hypersensitivity to inhaled capsaicin at 48 h and bronchial hyperresponsiveness to inhaled methacholine at 72 h after challenge with an aerosolized antigen in actively sensitized guinea pigs. After measuring bronchial responsiveness, we examined neutral endopeptidase (NEP) activity in the tracheal tissue. Carbocysteine (10, 30, or 100 mg/kg) was given intraperitoneally every 12 h for 3 days after antigen challenge. The number of coughs elicited by an aerosol of capsaicin (10(-4) M) was significantly (p < 0.01) decreased in carbocysteine groups (6.13 +/- 0.59 at 10 mg/kg, 4.88 +/- 0.67 at 30 mg/kg, and 4.50 +/- 0.33 at 100 mg/kg during 3 min measurement) compared with the control group (9.75 +/- 0.53). Furthermore, carbocysteine dose dependently repaired the antigen-induced decrease of NEP activity in the tracheal tissue, but it did not influence the bronchial hyperresponsiveness or bronchoalveolar lavage cell component. These findings suggest that carbocysteine promotes the repair of damaged epithelium by allergic reaction and may be useful in allergic airway diseases accompanied by isolated chronic coughing, especially eosinophilic bronchitis without asthma and tracheobronchitis with cough hypersensitivity.     

Arachidonic acid metabolites and airway epithelium-dependent relaxant factor

Exogenous arachidonic acid (10(-8) to 10(-4) M) contracted epithelium-free guinea pig tracheal strips. Intact tracheal strips were contracted slightly by low concentrations of arachidonic acid (10(-8) to 10(-5) M), but higher concentrations relaxed them. In contrast, when tracheal strips were precontracted with histamine or carbachol, exogenous arachidonic acid had no effect on epithelium-free preparations but induced concentration-dependent (10(-8) to 10(-4) M) relaxation of intact tracheal strips. The effects of arachidonic acid both in epithelium-free and epithelium-containing trachea were blocked by either indomethacin (10(-6) M) or aspirin (10(-4) M). Studies on the effects of exogenous arachidonic acid, performed with a "sandwich protocol," demonstrated that the postulated airway epithelium-dependent relaxant factor released by an intact tracheal strip relaxes an adjacent epithelium-free strip in the same organ bath. This relaxation is antagonized by indomethacin suggesting the involvement of a cyclooxygenase product in this phenomenon. Comparison of concentration-response curves for contractile agonists in epithelium-free preparations and in one containing epithelium suggests the mobilization of airway epithelium-dependent relaxant factor by histamine but not by carbachol. The effects of cyclooxygenase and lipoxygenase inhibitors indicated that both relaxant and contractile arachidonic acid metabolites are generated by epithelial and nonepithelial cells alike in response to contractile agonists.     

Determinants of lung bacterial clearance in normal mice.

The determinants of the lung clearance of Streptococcus pneumoniae, Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus were studied in normal mice after exposure to an aerosol of viable bacteria and 99mTc-labeled dead bacteria. The fraction of bacteria in lungs that remained viable 4 h after exposure were: S. pneumoniae, 7.3%; K. pneumoniae, 121%; E. coli, 88.5%; S. aureus, 27.6%. The rate of physical removal of bacterial particles (Kmc) was determined from the change in lung 99mTc counts with time: Kmc ranged between 7 and 12%/h and and was similar in all species. The rate of mucociliary clearance and of intrapulmonary bacterial killing (Kk + Kmc) was calculated from the change in bacterial counts with time in animals that had received tetracycline to inhibit bacterial multiplication. Kk, the rate of intrapulmonary killing, was obtained by subtraction of Kmc from (Kk + Kmc). The calculated values for Kk were: S. pneumoniae, - 87%/h; K. pneumoniae, - 17%/h; E. coli, - 18%/h; S. aureus, - 22%/h. The rate of intrapulmonary bacterial multiplication (Kg) was estimated from the relationship of bacterial counts in tetracycline and nontetracycline-treated animals, assuming that tetracycline altered only Kg. Kg, expressed as the doubling time, was: S. pneumoniae, 310 min; K. pneumoniae, 217 min; E.coli, 212 min; S. aureus, infinity (no multiplication). The data indicate that the marked differences in the clearance of these species from the normal mouse lung result from the interaction of differing rates of in vivo bacterial multiplication and killing.     

An unrecognized epidemic of Mycoplasma pneumoniae infection in Vienna

Mycoplasma pneumoniae infection shows epidemiological peaks with a 2- to 10-fold increased incidence every four to seven years. The regional epidemiology of M. pneumoniae infection is important with regard to empirical antibiotic treatment of community-acquired respiratory tract infections, which are the most common cause for visiting a physician. To date, no data on the epidemiology of M. pneumoniae in central Europe have been published. In the present study, the results of M. pneumoniae serology performed at the Clinical Division of Virology at Vienna General Hospital (a 2,140-bed university teaching hospital with an average of 94,000 admissions/year and 430,000 outpatient visits/year) in the 10-year period from January 1995 to December 2004 were analyzed retrospectively. Antibody titers > or = 1:64 in complement fixation tests were considered indicative of acute or recent mycoplasma infection. The annual total number of serum specimens tested for anti-M. pneumoniae antibodies remained stable throughout the study period (median: 2859 samples/year, range: 2257-3338). The annual median number of patients with high M. pneumoniae titers was 13. A major epidemiological peak (43 patients) was observed in 2000, the epidemic starting in late 1999 and ending in 2001. A surveillance or reporting system for M. pneumoniae infections (i.e. positive serological results for M. pneumoniae) would be useful for physicians caring for patients with community-acquired respiratory tract infections.     

国产明视插管软镜与Macintosh直接喉镜经鼻气管插管的比较*

目的比较国产明视插管软镜(VIS)与Macintosh直接喉镜经鼻气管插管的临床应用效果。方法择期口腔颌面部手术患者100例,美国麻醉医师协会(ASA)Ⅰ或Ⅱ级,年龄19~67岁,随机分为国产VIS组(V组)和Macintosh直接喉镜组(M组),每组50例。分别以国产VIS和Macintosh直接喉镜行经鼻气管插管。观察记录两组患者镜下Cormark-Lehane分级(简称C-L分级)、气管插管时间、首次气管插管成功率,观察记录麻醉诱导前(T_0)、麻醉诱导后(T_1)、声门显露时(T_2)、插管后即刻(T_3)、插管后1 min(T_4)、插管后3 min(T_5)的平均动脉压(MAP)和心率(HR)及气管插管相关并发症。结果 C-L分级V组明显优于M组,气管插管时间V组明显短于M组,首次气管插管成功率V组明显高于M组,差异均有统计学意义(P0.05)。与T_1时比较,V组T_3~T_4时MAP明显升高、T_3时HR明显增快,M组T_2~T_4时MAP明显升高、T2_~T_3时HR明显增快(均P0.05)。与M组比较,V组T_2~T_4时MAP和HR均明显降低(P0.05)。气管插管并发症总发生率V组明显低于M组(P0.05)。结论与Macintosh直接喉镜相比较,国产VIS经鼻气管插管声门暴露好,气管插管时间短,首次气管插管成功率高,血流动力学更稳定,且气管插管并发症少,值得临床推广应用。     

不同剂量右美托咪啶对冠心病患者气管插管血流动力学的影响

目的研究不同剂量右美托咪啶对冠心病患者气管插管血流动力学的影响。方法择期气管内插管全身麻醉行腹部外科手术冠心病患者75例,随机将其分成L组(右美托咪啶0.5μg/kg)、M组(右美托咪啶1.0μg/kg)、C组(咪唑安定对照组),每组25例。麻醉诱导前静脉泵注用生理盐水稀释成50 ml右旋美托咪啶,L组0.5μg/kg,M组1.0μg/kg,输注时间为20 min;C组全麻诱导时先静脉注射咪唑安定0.03～0.05 mg/kg。记录入室后基础值(T1)、全麻诱导前(T2)、插管前(T3),插管后即刻(T4),插管后3 min(T5)各时点的心率(HR)、有创血压值[收缩压(SBP)、舒张压(DBP)]、心电图(ECG)变化。结果与基础值相比较,输注右美托嘧啶后全麻诱导前L组、M组患者HR、SBP、DBP均下降(P<0.05),但两组之间差异无统计学意义(P>0.05)。气管插管前,三组患者的SBP、DBP、HR均降至最低(与基础值比较,P<0.05);三组间差异均无统计学意义(P>0.05)。气管插管前M组出现4例窦性心动过缓(<52次/min),3例低血压(SBP下降>40%);L组出现1例窦性心动过缓;C组出现1例低血压,2例窦性心动过速。气管插管后即刻三组患者血压、心率有不同程度上升;C组HR、SBP、DBP与插管前L组、M组相比明显上升(P<0.05)。L组、M组与插管前相比差异无统计学意义(P>0.05)。气管插管后3 min,C组血压、心率与气管插管后即刻比较有明显下降(P<0.05);与插管前相比仍明显升高(P<0.05)。L组、M组血压、心率与插管后即刻、插管前比较差异无统计学意义(P>0.05)。结论冠心病患者术前输注右美托咪啶可减少气管插管血流动力学变化;0.5μg/kg右美托咪啶可能更适合冠心病患者。     

临床咽拭子标本反复冻融对肺炎支原体分离效果的影响

目的了解临床呼吸道标本反复冻融对肺炎支原体分离培养的影响,促进肺炎支原体临床标本分离培养工作的开展。方法选取2008-2009年北京临床医院150份肺炎病例咽拭子标本,使用液体培养并通过颜色变化单位(CCU)测定法检测标本中活菌,对1～4次冻融样本的阳性培养率和/或活菌量进行分析。结果临床咽拭子标本(200μl)中肺炎支原体携带量主要在0～103CCU之间。带菌量≤10 CCU的标本占培养阳性标本的40%左右,此类标本带菌量为临界培养检测限,经每次冻融会造成约1/4的阳性标本培养转阴。带菌量10 CCU的标本,经3次反复冻融后均培养阳性,且CCU计数无明显变化,但培养阳性时间平均每次延长14 h左右。结论鉴于反复冻融对低病原体含量样品分离率的明显影响和对样品培养所需时间的明显延长,可能是影响临床样本支原体分离率的重要因素,应在样品分离培养前避免样品的反复冻融。