Tracheal Blood Research Articles

Complexity measures of the central respiratory networks during wakefulness and sleep

Since sleep is known to influence respiratory activity we studied whether the sleep state would affect the complexity value of the respiratory network output. Specifically, we tested the hypothesis that the complexity values of the diaphragm EMG (EMGdia) activity would be lower during REM compared to NREM. Furthermore, since REM is primarily generated by a homogeneous population of neurons in the medulla, the possibility that REM-related respiratory output would be less complex than that of the awake state was also considered. Additionally, in order to examine the influence of neuron vulnerabilities within the rostral ventral medulla (RVM) on the complexity of the respiratory network output, we inhibited respiratory neurons in the RVM by microdialysis of GABAA receptor agonist muscimol. Diaphragm EMG, nuchal EMG, EEG, EOG as well as other physiological signals (tracheal pressure, blood pressure and respiratory volume) were recorded from five unanesthetized chronically instrumented intact piglets (3–10 days old). Complexity of the diaphragm EMG (EMGdia) signal during wakefulness, NREM and REM was evaluated using the approximate entropy method (ApEn). ApEn values of the EMGdia during NREM and REM sleep were found significantly (p < 0.05 and p < 0.001, respectively) lower than those of awake EMGdia after muscimol inhibition. In the absence of muscimol, only the differences between REM and wakefulness ApEn values were found to be significantly different.

À propos d’un cas de fongémie à Kodamaea ohmeri : difficultés d’identification et revue de la littérature

Kodamaea ohmeri is a yeast that has rarely been isolated in human disease. Since the first reported case of fungemia in 1998, 15 cases of local or disseminated infections involving K. ohmeri have been reported. Here, we report the case of a 91-year-old woman who was admitted for impairment of her general condition and underwent a laparotomy because intestinal ischemia was suspected. On day 18, pulmonary embolism was diagnosed. In the following days, she presented intermittent fever, cyanosis of the extremities and an elevated white blood cells counts. Tracheal aspiration, urine and blood cultures revealed the presence of a yeast, first identified on chromogenic media as Candida albicans. The cultures were examined again after 96 hours and after biochemical analysis and molecular sequencing K. ohmeri was identified. Progressive deterioration of respiratory function led to the death of the patient on day 25.

In Vivo Actions of Angiopoietins on Quiescent and Remodeling Blood and Lymphatic Vessels in Mouse Airways and Skin

We investigated and compared the in vivo effects of all four angiopoietins (COMP-Ang1, Ang2, Ang3, and Ang4) on blood and lymphatic vascular remodeling in adult mice. We analyzed the microvasculature of trachea and ear skin, and compared quiescent skin microvasculature with that during wound healing. We were able to achieve similar levels of relatively long-term and sustained circulating expression of each angiopoietin using an adenoviral delivery system. Two weeks after treatment, we observed tracheal blood and lymphatic vascular enlargement, and lymphatic filopodia formation, with the following order of potency: COMP-Ang1>Ang3=Ang4>Ang2. Co-treatment with Ang2 attenuated Ang1-induced tracheal blood and lymphatic remodeling. In the normal ear skin, all angiopoietins induced blood vessel enlargement, whereas none induced lymphatic vascular remodeling. However, in the healing margin of ear skin wounds, all angiopoietins strongly induced lymphatic vascular enlargement and formation of lymphatic sprouts and filopodia, while they potentiated blood vascular enlargement. Co-treatment of Ang2 with Ang1 produced an additive effect on these changes. This study, one of the first to our knowledge to characterize the in vivo actions of all 4 angiopoietins, may expand the current concepts for use of angiopoietins for therapeutic angiogenesis and lymphangiogenesis.

An in vitro study of the compliance of paediatric tracheal tube cuffs and tracheal wall pressure

Cuff volume-pressure curves and cuff pressure-tracheal wall pressure relationships were investigated in eight brands of currently available cuffed, paediatric tracheal tubes with internal diameters of 5.0 mm. Cuff volume-pressure curves were measured with the cuff unrestricted and with the cuff placed within a tracheal model with wall pressure measurements. With the tracheal tube cuffs, unrestricted cuff compliance at 20 cmH(2)O cuff pressure varied between 0.06 and 0.3 ml x cmH(2)O(-1). With the cuff restricted within the model trachea, all tracheal tube cuffs became considerably less compliant (0.01-0.09 ml x cmH(2)O(-1)). We found tracheal wall pressure was similar to the cuff pressure as long as the resulting cuff diameter was sufficiently large freely to drape the inner tracheal wall. We found that, regardless of whether a higher or lower compliant tube cuff was used, cuff hyperinflation uniformly resulted in potentially compromised tracheal mucosal blood flow; cuff pressure monitoring using cuff pressure limitation is therefore strongly recommended.

Gabapentin attenuates the pressor response to direct laryngoscopy and tracheal intubation

Laryngoscopy and tracheal intubation increase blood pressure and heart rate (HR). The aim of the present study was to investigate the effect of gabapentin when given before operation on the haemodynamic responses to laryngoscopy and intubation. Forty-six patients undergoing abdominal hysterectomy for benign disease were randomly allocated to receive gabapentin 1,600 mg or placebo capsules at 6 hourly intervals starting the day (noon) before surgery. Anaesthesia was induced with propofol and cis-atracurium. Systolic, diastolic arterial blood pressures (SAP, DAP) and heart rate (HR) were recorded before and after the anaesthetic and 0, 1, 3, 5 and 10 min after tracheal intubation. SAP was significantly lower in the gabapentin vs the control group 0, 1, 3, 5 and 10 min after intubation [128 (27) vs 165 (41), P=0.001, 121 (14) vs 148 (29), P=0.0001, 115 (13) vs 134 (24), P=0.002, 111 (12) vs 126 (19), P=0.004 and 108 (12) vs 124 (17), P=0.001 respectively]. DAP also was lower in the gabapentin group 0, 1, 3, and 10 min after intubation [81 (18) vs 104 (19), P=0.0001, 77 (9) vs 91 (16), P=0.001, 71 (10) vs 84 (13), P=0.001 and 67 (10) vs 79 (12), P=0.004]. HR did not differ between the two groups at any time [82 (11) vs 83 (15), 79 (10) vs 80 (12), 86 (17) vs 92 (10), 82 (11) vs 88 (10), 81 (12) vs 81 (11), 77 (13) vs 79 (13), and 75 (15) vs 78 (12)]. Gabapentin, under the present study design attenuates the pressor response but not the tachycardia associated with laryngoscopy and tracheal intubation.

Nosocomial Infections at Kenyatta National Hospital Intensive-Care Unit in Nairobi, Kenya

The objective of this study was to identify the common bacteria isolated from patients, antibiotics used, sensitivity patterns, therapeutic procedures and cleaning protocols practised in Kenyatta National Hospital Intensive-Care Unit (ICU). Kenyatta National Hospital is a 1,800-bed referral and tertiary-care hospital which is also the Teaching University Hospital. The ICU has 20 beds. Two members of staff, a consultant and a senior nurse, did the study. Out of 195 patients admitted to the unit during the study period, 137 (70.3%) received antibiotics. The most frequently prescribed antibiotics included meropenem, ceftazidime, cefuroxime, piperacillin tazobactam, vancomycin, Augmentin and Flagyl. The most common bacteria isolated were Pseudomonas aeruginosa,Klebsiella, Citrobacter, Staphylococcus aureus, Staphylococcus pneumoniae,Acinetobactor and Escherichia coli isolated from tracheal aspirate, urine, blood and pus swabs.

Long-Term and Sustained COMP-Ang1 Induces Long-Lasting Vascular Enlargement and Enhanced Blood Flow

Vascular enlargement is a characteristic feature of angiopoietin-1 (Ang1)-induced changes in adult blood vessels. However, it is unknown whether tissues having Ang1-mediated vascular enlargement have more blood flow or whether the enlargement is reversible. We have recently created a soluble, stable and potent Ang1 variant, COMP-Ang1. In the present study, we investigated the effects of varied dose and duration of COMP-Ang1 on vascular enlargement and blood flow in the tracheal microvasculature of adult mice and explored a possible mechanism of long-lasting vascular enlargement. We found that COMP-Ang1 administered by adenoviral vector induced long-lasting vascular enlargement and increased tracheal blood flow. In contrast, short-term administration of COMP-Ang1 recombinant protein induced transient vascular enlargement that spontaneously reversed within a month. In both cases, the vascular enlargement resulted from endothelial proliferation. The COMP-Ang1-induced vascular remodeling is mediated mainly through Tie2 activation. Sustained overexpression of Tie2 could participate in the maintenance of vascular changes. Together, our findings indicate that sustained treatment with COMP-Ang1 can produce long-lasting vascular enlargement and increased blood flow.

Proseal Laryngeal Mask Airway for the Resection of a High Grade Upper Tracheal Stenosis: A case report

Laryngeal mask airways (LMAs) have several advantages compared with conventional endotracheal tube (ETT) in tracheal surgery. LMAs cannot penetrate the airway below the level of the glottis, but enable the access to the larynx and tracheobronchial tree while avoiding airflow impairment, tracheal stimulation, trauma, and the interference of tracheal mucosal blood flow. Moreover, LMAs have lower airway resistance than ETTs. We describe the use of a proseal laryngeal mask airway (PLMA) in patients with high grade upper tracheal stenosis. We suggest that PLMA might have advantages over the classic LMA by preventing aspiration and by allowing the evacuation of air from the stomach in high-grade upper tracheal stenosis.

Relationship between histologic chorioamnionitis and early inflammatory variables in blood, tracheal aspirates, and endotracheal colonization in preterm infants.

Histologic results of the placenta are usually not available within the first days of life. We identified inflammatory variables in tracheal aspirates and blood that were associated with histologic chorioamnionitis (HC). A derivation cohort consisted of 62 neonates and a validation cohort of 57 neonates with a gestational age < 31 wk and ventilated on d 1. Tracheal aspirates were taken on d 1 and on d 3, if the patient was still ventilated. HC was diagnosed by light microscopy. Logistic regression was used to identify independent factors in the derivation cohort associated with HC at d 1, 2, and 3. Model performance was studied using receiver operating characteristic curve analysis. Independent factors associated with HC were, at d 1, tracheal aspirate IL-8 >or= 917 pg/mL (odds ratio, 60.7; 95% confidence interval, 11-328); at d 2, blood C-reactive protein >or= 14 mg/L (odds ratio, 9.2; 95% confidence interval, 2-38), blood white blood cell count >or= 10400/mm3 (odds ratio, 7.4; 95% confidence interval, 2-28); and at d 3, blood neutrophil count >or= 4968/mm3 (odds ratio, 14; 95% confidence interval, 3-57). The association with HC was less at d 3 (area under receiver operating characteristic curve, 0.77) when compared with the d 1 model (area under the curve, 0.88; p = 0.09). The models performed equally well in the validation cohort (goodness-of-fit test, p > 0.05). We conclude that the d 1 and d 2 models can be used as diagnostic factors for HC. Tracheal aspirate IL-8 taken immediately after birth was equally accurate in the diagnosis of HC as systemic inflammatory response at d 2 and better than on d 3.

Simple on-line endotracheal cuff pressure relief valve.

Ischemic injury of the tracheal mucosa in the endotracheally intubated patient is directly proportional to the tracheal tube cuff pressure. At a cuff pressure of 30 cm H2O, the tracheal mucosal blood flow becomes partially obstructed, and at a pressure of 45 cm H2O, the obstruction to the tracheal mucosal blood becomes total, leading to tracheal mucosal damage and subsequent complications. In our institute, we have developed a simple and very inexpensive method to gauge the cuff pressure. We use a regular 20-mL syringe attached in line with the connector of the endotracheal tube cuff. In this manner, we monitored the intracuff pressure in 120 patients who underwent ear or neck surgery. The syringe was connected to the tube cuff and inflated with 15 mL of air. The syringe was left constantly connected to the cuff. In addition, the cuff pressure was measured with the Mallinckrodt Hi-Lo aneroid pressure gauge at the beginning of surgery and hourly thereafter for the duration of surgery. At the same time, a check for leakage around the cuff was made by auscultation with a stethoscope above the sternal notch. Multiple comparisons between the repetitive intracuff pressure measurements revealed that there were no significant differences in the intracuff pressure values measured at the different times of surgery. These results indicate that there was an adequate venting of the excess intracuff pressure and also that there was no leakage around the cuff.

Hypersensitivity reactions in mouse airways after a single and a repeated hapten challenge.

In this study, we examined the effect of a single and a repeated hapten-challenge on inflammatory processes in the airways of mice undergoing a hapten-induced non-IgE mediated hypersensitivity reaction. BALB/c mice were skin-sensitized with the hapten dinitroflourobenzene (DNFB) and intra-airway challenged with dinitrobenzene sulphonic acid (DNS). Mucosal exudation, tracheal vascular permeability, cellular accumulation, and serum murine mast cell protease (MMCP) were investigated at different time points after the first DNS-challenge and 30 min after a repeated DNS-challenge. MMCP levels in serum were increased at all time points after single challenge and repeated challenge. Increased vascular permeability as determined by Monastral blue staining, was found in the trachea of DNFB-sensitized mice after single DNS-challenge. A second exposure to DNS profoundly enhanced the Monastral blue labeling of the tracheal blood vessels of DNFB-sensitized mice. Furthermore, increased mucosal exudation and polymorphonuclear cell (PMN) accumulation were present in DNFB-sensitized mice compared to vehicle-sensitized animals after the first DNS challenge. Increased mucosal exudation, vascular permeability, and PMN accumulation are prominent inflammatory features of the DNFB-induced hypersensitivity reaction in the airways. Furthermore, mast cell activation is associated with this hapten-induced hypersensitivity reaction.

Organophosphorous poisoning with intermediate syndrome

Organophosphorous poisoning with intermediate syndrome

Effect of fudosteine, a cysteine derivative, on blood flow of tracheal microvasculature increased by airway inflammation

We examined the effect of fudosteine, a cysteine derivative, on blood flow of tracheal microvasculature increased by airway inflammation. Airway inflammation was elicited by sulfur dioxide (SO 2) exposure for 2 weeks in rabbits. Each drug (500 mg/kg, p.o.) or 0.5% carboxymethylcellulose-Na (control group) was daily administered just before SO 2 exposure. After final SO 2 exposure was finished, blood flow of tracheal microvasculature was measured by blood perfusion monitor. Fudosteine or S-carboxymethylcysteine ( S-CMC) significantly suppressed blood flow of tracheal microvasculature increased by SO 2 exposure. However, no effect of fudosteine was observed on the pharmacological microvascular response in trachea of SO 2-exposed rabbits. On the other hand, fudosteine or S-CMC scavenged superoxide anion generated from rat neutrophils, and enzymatically generated from xanthine oxidase-acetaldehyde reaction. The results suggest that suppressive action in increased tracheal blood flow of fudosteine is due to anti-inflammatory activity, at least in part, via scavenging of superoxide anion.

Serial changes in levels of IL-6 and IL-1beta in premature infants at risk for bronchopulmonary dysplasia.

The aim of this study was to define the inflammatory changes occurring in the lungs of infants at risk for bronchopulmonary dysplasia (BPD) over the first 28 days of life, and to define an optimal strategy for steroids therapy in the prevention of BPD. We measured levels of interleukin-6 (IL-6) and interleukin-1 beta (IL-1beta) in tracheal aspirate (TA) samples and blood of premature infants with severe respiratory distress syndrome RDS (n = 45) on the first day of life prior to initiation of surfactant therapy and on days 5-7, 12-14, 19-21, and 26-28. Levels of IL-6 and IL-1beta were determined with a commercially available enzyme-linked immunoassay. Logistic regression analyses were performed in order to examine differences in trends in levels of IL-6 and IL-1beta between groups of infants. Infants were divided into group I (n = 30, FiO(2) < or = 0.35 at 28 days) and group II (n = 15, FiO(2) > 0.35 based on their likelihood of developing BPD at 36 weeks postconceptional age (PCA). The infants were comparable with respect to mean ( +/- SEM) birth weight (895 +/- 33 g vs. 900 +/- 40 g), gestational age (27 +/- 0.38 weeks vs. 27 +/- 0.54 weeks), and severity of respiratory illness at entry into the study (mean airway pressure: 12 +/- 1 cmH(2)O vs. 12 +/- 1 cmH(2)O, and oxygen index: 15 +/- 2 vs. 19 +/- 4) (group I vs. group II, respectively). Logistic regression analyses failed to reveal any significant differences in linear trends of levels of IL-6 and IL-1beta in TA samples between both groups of infants. No particular pattern of change in levels of IL-6 or IL-1beta could be identified among groups of infants. Levels of IL-6 and IL-1beta in TA samples on the first day of life failed to predict the need for FiO(2) > 0.35 at 28 days of age. We could not identify an increasing trend or a specific pattern of changes in postnatal levels of IL-6 or IL-1beta in TA samples of infants who were at greater risk of developing BPD at 36 weeks PCA compared to infants who were not.

Transmission of a multiresistant Pseudomonas aeruginosa strain at a German University Hospital

Over 15 months, 60 patients at a German University Hospital became infected or colonized by a multiresistant Pseudomonas aeruginosa strain, which was isolated from tracheal secretions, blood, urine, venous catheters, ascites and several wounds. Most patients had undergone invasive treatment (surgery, cancer therapy).The genetic relationship of the isolates was investigated by pulsed field gel electrophoresis. The isolates were resistant to β-lactam antibiotics, including carbapenems and aztreonam, to aminoglycosides and quinolones. The only in vitro susceptibility was to polymyxin B.Extensive sampling was carried out to identify contaminated medical devices, surfaces or media (water, food). Samples were taken from doctors and nursing staff and various treatment procedures were observed for several weeks. The handling of respirators, resuscitation tubes, urine bottles, and bedpans resulted in the contamination of the patients' environment, although most devices were cleaned and disinfected with automatic washer/disinfectors. Several wash basins on the intensive care unit were contaminated, but none of the drinking water samples showed any growth of P. aeruginosa.We recommend the strict use of gloves and strict application of alcoholic hand disinfectants immediately after discarding the gloves. The chain of infection ceased after strict cohort isolation and the subsequent introduction of the specific hygiene regime.

Surveillance tracheal aspirate in ventilator associated pneumonia (VAP)

VAP is associated with increased ICU stay and mortality, particularly when treatment is delayed or inappropriate [1]. When a clinical suspicion of VAP is justified, specific diagnostic tests are usually conducted: bronchoalveolar lavage (BAL), protected specimen brushing (PSB), diagnostic tracheal aspirate (dTA), blood cultures and pleural fluid. We evaluated the concordance between specific diagnostic tests and the surveillance tracheal aspirates (sTA).

The excitatory amino acid glutamate mediates reflexly increased tracheal blood flow and airway submucosal gland secretion

In six decerebrated and in eight α-chloralose anesthetized, paralyzed and mechanically ventilated beagle dogs, we have studied involvement of glutamate and glutamate receptors in transmission of excitatory inputs from the airway sensory receptors to the nucleus tractus solitarius and from this site to airway-related vagal preganglionic cells that regulate the tracheal circulation and the submucosal gland secretion. Stimulation of airway sensory fibers by lung deflation-induced reflex increase in tracheal blood flow and submucosal gland secretion. These responses were diminished by prior administration of AMPA/kainate receptor antagonist CNQX into the fourth ventricle ( n=6). Furthermore, topical application or microinjection of AMPA/kainate receptor blockers, into the region of the ventrolateral medulla, where airway-related vagal preganglionic neurons are located, abolished the reflex changes in tracheal submucosal gland secretion ( n=8); in these dogs mucosal blood flow was not measured). These findings indicate that reflex increase in tracheal blood flow and submucosal gland secretions are mediated mainly via release of glutamate and activation of the AMPA/kainate subtype of glutamate receptors.

Effects of dental plaque antiseptic decontamination on bacterial colonization and nosocomial infections in critically ill patients

To document in intensive care unit (ICU) patients the effect of dental plaque antiseptic decontamination on the occurrence of plaque colonization by aerobic nosocomial pathogens and nosocomial infections. Single-blind randomized comparative study. A 16-bed adult intensive care unit in a university hospital. Patients consecutively admitted in the ICU with a medical condition suggesting an ICU stay of 5 days and requiring mechanical ventilation. After randomization, the treated group received dental plaque decontamination with 0.2% chlorhexidine gel, three times a day during the ICU stay. The control group received standard oral care. SPECIFIC MEASUREMENTS: Dental status was assessed by the Caries-Absent-Occluded index; the amount of dental plaque was assessed by a semi-quantitative plaque index. Bacterial sampling of dental plaque, nasal and tracheal aspirate, blood, and urine cultures were done on days 0, 5, 10, and every week. Sixty patients were included; 30 in the treated group and 30 in the control one (mean age: 51 +/- 16 years; mean Simplified Acute Physiological Score II: 35 +/- 14 points). On admission, no significant differences were found between both groups for all clinical and dental data. Compared with the control group, the nosocomial infection rate and the incidence densities related to risk exposition were significantly lower in the treated group (18 vs 33% days in the ICU and 10.7 vs 32.3% days of mechanical ventilation; P < 0.05). These results were consistent with a significant preventive effect of the antiseptic decontamination (Odds Ratio: 0.27; 95% CI: 0.09; 0.80) with a 53% relative risk reduction. There was a trend to a reduction of mortality, length of stay, and duration of mechanical ventilation. An antiseptic decontamination of dental plaque with a 0.2% chlorhexidine gel decreases dental bacterial colonization, and may reduce the incidence of nosocomial infections in ICU patients submitted to mechanical ventilation.

Experimental and Serologic Observations on Avian Pneumovirus (APV/Turkey/Colorado/97) Infection in Turkeys

An avian pneumovirus (APV) was isolated from commercial turkeys in Colorado (APV/Colorado) showing clinical signs of a respiratory disease. The results of virus neutralization and indirect fluorescent antibody tests showed that the APV/Colorado was partially related to APV subgroup A but was unrelated to APV subgroup B. Turkeys experimentally inoculated with the APV/Colorado were observed for signs, lesions, seroconversion, and virus shedding. Thirty-six 7-wk-old turkeys were distributed into three groups. Eighteen turkeys were inoculated oculonasally with APV/Colorado, six were placed in contact at 1 day postinoculation (DPI), and 12 served as noninoculated controls. Tracheal swabs and blood samples were collected at 3, 5, 7, 10, 14, and 21 DPI. Tissues were collected from three inoculated and two control turkeys on aforementioned days for pathologic examination and APV isolation. Inoculated turkeys developed respiratory disease, yielded APV at 3, 5, and 7 DPI, and seroconverted at 10 DPI. Contact turkeys yielded APV at 7 and 10 DPI. No gross lesions were observed in the turbinates, infraorbital sinuses, and trachea. However, microscopic examination revealed acute rhinitis, sinusitis, and tracheitis manifested by congestion, edema, lymphocytic and heterophilic infiltration, and loss of ciliated epithelia. The inflammatory lesions were seen at 3 DPI and became extensive at 5 and 7 DPI. Active regenerative changes in the epithelia were seen at 10 and 14 DPI. Serologic survey for the presence of antibodies in commercial turkeys (24,504 sera from 18 states) and chickens (3,517 sera from 12 states) to APV/Colorado showed seropositive turkeys in Minnesota, North Dakota, and South Dakota and no seropositive chickens. This report is the first on the isolation of an APV and APV infection in the United States.

Portable ultrasonic scanning of the anterior neck before percutaneous dilatational tracheostomy.

We used portable ultrasound scans to identify relevant anatomical structures in the necks of 30 patients before percutaneous tracheostomy. We identified the tracheal midline, thyroid isthmus and blood vessels and located a safe level for needle insertion. Anterior jugular veins were seen in 15 patients; eight were near the midline and were considered vulnerable. Three veins were more than 4 mm in diameter and these larger vessels were electively ligated. Four patients had arteries which were considered vulnerable to damage. All patients underwent successful percutaneous tracheostomy. Portable ultrasound provides a simple method of screening for vulnerable blood vessels in the neck and for locating the midline before percutaneous tracheostomy. This method is particularly suitable for patients with landmarks that are difficult to visualise or palpate. Based on the ultrasonic findings we can make an informed decision about referral for surgical tracheostomy.