Impact of early vs. late tracheostomy on weaning: a retrospective analysis

BACKGROUND

Early tracheostomy has been advocated for a number of reasons. Especially in association with weaning from mechanical ventilation, it is known that an early timepoint can help patients being weaned more rapidly from the ventilator. However, timing of tracheostomy is still unknown and evidence is lacking. The effects of early tracheostomy compared with intermediate and late tracheostomy were assessed in critically ill patients.

METHODS

Data collected from January 2005 to December 2007 were conducted for retrospective analysis. All patients needing tracheostomy due to extubation failure and/or weaning failure were included (N.=296). Early tracheostomy (ET) was defined as ≤4 days, intermediate tracheostomy (IT) as tracheostomy within 5-9 days, and late tracheostomy (LT) was defined as ≥10 days after endotracheal intubation. After proving normal distribution, significant changes between the three groups were tested by ANOVA followed by post hoc tests for multiple comparisons (Bonferroni's test).

RESULTS

Intensive care unit (ICU) mortality was significantly higher in the LT group when being compared with the ET but not when being compared with the IT group (40.7% vs. 24.8% vs. 17.1%). Further, a significantly reduced incidence of VAP and sepsis, a smaller amount of ventilator days and a shorter ICU length of stay could be observed for the ET group. Length of weaning was not significantly different between the groups.

CONCLUSION

The length of weaning after tracheostomy is not affected by the timing. It seems beneficial to favour early tracheostomy in order to reduce the time of mechanical ventilation and its associated risks.

[Comments on the 2010 guidelines on cardiopulmonary resuscitation of the European Resuscitation Council]

ADULTS

Administer chest compressions (minimum 100/min, minimum 5 cm depth) at a ratio of 30:2 with ventilation (tidal volume 500-600 ml, inspiration time 1 s, F(I)O₂ if possible 1.0). Avoid any interruptions in chest compressions. After every single defibrillation attempt (initially biphasic 120-200 J, monophasic 360 J, subsequently with the respective highest energy), chest compressions are initiated again immediately for 2 min independent of the ECG rhythm. Tracheal intubation is the optimal method for securing the airway during resuscitation but should be performed only by experienced airway management providers. Laryngoscopy is performed during ongoing chest compressions; interruption of chest compressions for a maximum of 10 s to pass the tube through the vocal cords. Supraglottic airway devices are alternatives to tracheal intubation. Drug administration routes for adults and children: first choice i.v., second choice intraosseous (i.o.). Vasopressors: 1 mg epinephrine every 3-5 min i.v. After the third unsuccessful defibrillation amiodarone (300 mg i.v.), repetition (150 mg) possible. Sodium bicarbonate (50 ml 8.4%) only for excessive hyperkaliemia, metabolic acidosis, or intoxication with tricyclic antidepressants. Consider aminophylline (5 mg/kgBW). Thrombolysis during spontaneous circulation only for myocardial infarction or massive pulmonary embolism; during on-going cardiopulmonary resuscitation (CPR) only when indications of massive pulmonary embolism. Active compression-decompression (ACD-CPR) and inspiratory threshold valve (ITV-CPR) are not superior to good standard CPR.

CHILDREN

Most effective improvement of outcome by prevention of full cardiorespiratory arrest. Basic life support: initially five rescue breaths, followed by chest compressions (100-120/min depth about one third of chest diameter), compression-ventilation ratio 15:2. Foreign body airway obstruction with insufficient cough: alternate back blows and chest compressions (infants), or abdominal compressions (children >1 year). Treatment of potentially reversible causes: ("4 Hs and 4 Ts") hypoxia and hypovolaemia, hypokalaemia and hyperkalaemia, hypothermia, and tension pneumothorax, tamponade, toxic/therapeutic disturbances, thrombosis (coronary/pulmonary). Advanced life support: adrenaline (epinephrine) 10 µg/kgBW i.v. or i.o. every 3-5 min. Defibrillation (4 J/kgBW; monophasic or biphasic) followed by 2 min CPR, then ECG and pulse check. NEWBORNS: Initially inflate the lungs with bag-valve mask ventilation (p(AW) 20-40 cmH₂O). If heart rate remains <60/min, start chest compressions (120 chest compressions/min) and ventilation with a ratio 3:1. Maintain normothermia in preterm babies by covering them with foodgrade plastic wrap or similar. POSTRESUSCITATION PHASE: Early protocol-based intensive care stabilization; initiate mild hypothermia early regardless of initial cardiac rhythm [32-34°C for 12-24 h (adults) or 24 h (children); slow rewarming (<0.5°C/h)]. Consider percutaneous coronary intervention (PCI) in patients with presumed cardiac ischemia. Prediction of CPR outcome is not possible at the scene, determine neurological outcome <72 h after cardiac arrest with somatosensory evoked potentials, biochemical tests and neurological examination. ACUTE CORONARY SYNDROME: Even if only a weak suspicion of an acute coronary syndrome is present, record a prehospital 12-lead ECG. In parallel to pain therapy, administer aspirin (160-325 mg p.o. or i.v.) and clopidogrel (75-600 mg depending on strategy); in ST-elevation myocardial infarction (STEMI) and planned PCI also prasugrel (60 mg p.o.). Antithrombins, such as heparin (60 IU/kgBW, max. 4000 IU), enoxaparin, bivalirudin or fondaparinux depending on the diagnosis (STEMI or non-STEMI-ACS) and the planned therapeutic strategy. In STEMI define reperfusion strategy depending on duration of symptoms until PCI, age and location of infarction. TRAUMA: In severe hemorrhagic shock, definitive control of bleeding is the most important goal. For successful CPR of trauma patients a minimal intravascular volume status and management of hypoxia are essential. Aggressive fluid resuscitation, hyperventilation and excessive ventilation pressure may impair outcome in patients with severe hemorrhagic shock.

TRAINING

Any CPR training is better than nothing; simplification of contents and processes is the main aim.

Outcome and mortality risk factors in long-term treated ICU patients: a retrospective analysis

BACKGROUND

Little is known about the prognosis and outcome of critically ill patients with a prolonged length of stay (LOS). The aim of this study was to examine mortality and its risk factors in patients requiring intensive care therapy for more than 30 days.

METHODS

A retrospective, single-center analysis of data collected in a surgical intensive care unit (ICU) of a university hospital in Germany from 2005 to 2007 was conducted. All demographic data and clinical variables were collected. A univariate analysis followed by multivariate regression was performed to detect the relevant risk factors for short and long-term mortality.

RESULTS

Altogether, 10 737 patients were admitted to the ICU; 136 patients fulfilled the criteria for long-term treatment, 75% (N=102) of whom were discharged from ICU. The one-year survival rate was 61.8% (N=60). The most significant risk factors were pulmonary compromise with prolonged mechanical ventilation and infectious disorders leading to sepsis. However, sepsis was not a predictor of outcome. Weaning failure was present in 67.6% (N=92) at day 30 but was reduced to 37.5% of the cases (N=51) over the total course of the stay. Acute and long-term prognoses were determined by a successful weaning.

CONCLUSION

Although the long-term treatment of critically ill patients requires significant effort, the outcome for this particular cohort was reasonably favorable. Prolonged mechanical ventilation and weaning are the factors that influence mortality independently of sepsis. Because reasonable improvements can be shown even after a prolonged LOS, further attention should be paid to weaning processes.

Performance of cardiac output measurement derived from arterial pressure waveform analysis in patients requiring high-dose vasopressor therapy

BACKGROUND

Arterial pressure waveform analysis of cardiac output (APCO) without external calibration (FloTrac/Vigileo™) is critically dependent upon computation of vascular tone that has necessitated several refinements of the underlying software algorithms. We hypothesized that changes in vascular tone induced by high-dose vasopressor therapy affect the accuracy of APCO measurements independently of the FloTrac software version.

METHODS

In this prospective observational study, we assessed the validity of uncalibrated APCO measurements compared with transpulmonary thermodilution cardiac output (TPCO) measurements in 24 patients undergoing vasopressor therapy for the treatment of cerebral vasospasm after subarachnoid haemorrhage.

RESULTS

Patients received vasoactive support with [mean (sd)] 0.53 (0.46) µg kg(-1) min(-1) norepinephrine resulting in mean arterial pressure of 104 (14) mm Hg and mean systemic vascular resistance of 943 (248) dyn s(-1) cm(-5). Cardiac output (CO) data pairs (158) were obtained simultaneously by APCO and TPCO measurements. TPCO ranged from 5.2 to 14.3 litre min(-1), and APCO from 4.1 to 13.7 litre min(-1). Bias and limits of agreement were 0.9 and 2.5 litre min(-1), resulting in an overall percentage error of 29.6% for 68 data pairs analysed with the second-generation FloTrac(®) software and 27.9% for 90 data pairs analysed with the third-generation software. Precision of the reference technique was 2.6%, while APCO measurements yielded a precision of 29.5% and 27.9% for the second- and the third-generation software, respectively. For both software versions, bias (TPCO-APCO) correlated inversely with systemic vascular resistance.

CONCLUSIONS

In neurosurgical patients requiring high-dose vasopressor support, precision of uncalibrated CO measurements depended on systemic vascular resistance. Introduction of the third software algorithm did not improve the insufficient precision (>20%) for APCO measurements observed with the second software version.

[Current developments in xenon research. Importance for anesthesia and intensive care medicine]

The noble gas xenon exerts favorable anesthetic properties along with remarkable hemodynamic stability in healthy patients undergoing elective surgery. It represents the nearly ideal anesthetic and provides safe and well controllable anesthesia although the exact mechanism by which xenon produces anesthesia remains to be elucidated. In addition xenon offers organ protective properties for vital organs including the brain, heart and kidneys which seem to be synergistic when used in combination with therapeutic hypothermia. As the high cost of xenon will probably preclude its wider use as a routine anesthetic, data from extensive tests in large numbers of high risk patients is needed to confirm its possible superiority in this setting.

Xenon: recent developments and future perspectives

The noble gas xenon exerts favorable anesthetic properties along with remarkable hemodynamic stability in healthy patients undergoing elective surgery. Recent investigations documented that it does not prolong the duration of widely used neuromuscular blocking agents, including mivacurium and rocuronium. Some studies also suggest reduced neurocognitive compromise in the very early phase after general anesthesia. These properties differ from those observed for conventional inhalational anesthetics like isoflurane, desflurane and sevoflurane. However, a wider use of xenon in daily clinical routine has been limited owing to its higher price and technical restraints regarding economic delivery. Although there are controversial opinions, xenon seems to exert its main anesthetic features via the glutamate receptor. Recently, a novel binding cavity on the NMDA-subtype glutamate receptor has been elucidated that is occupied by xenon as well as isoflurane. Studies utilizing advanced imaging technologies have furthermore revealed that xenon markedly suppresses cerebral blood flow and glucose metabolism in distinct regions of the human brain. These investigations promise to further the understanding of the basic mechanisms underlying the induction and maintenance of anesthesia in general. Results from in vitro studies and various animal models have consistently demonstrated organoprotective properties of xenon, mainly in settings of ischemia and reperfusion injury. Interestingly, these effects have frequently been observed at subanesthetic concentrations and seem to be synergistic when used in combination with therapeutic hypothermia. Future studies will have to prove whether the high costs of xenon administration might be outweighed by its ability to substantially reduce the sequelae of myocardial and cerebral ischemia.

A comparison of waste gas concentrations during xenon or nitrous oxide anaesthesia

BACKGROUND AND OBJECTIVE

The aim of this study was to compare waste gas concentrations during xenon or nitrous oxide anaesthesia.

METHODS

A total of 64 patients were included in this study. Gas concentrations were measured with a mass spectrometer during anaesthesia. The probes were taken beside the patient's head and thorax and at a height of 180 cm above and at the floor level.

RESULTS

In both groups, waste gas concentrations peak after intubation and extubation. Waste gas levels during xenon anaesthesia are low compared with nitrous oxide.

CONCLUSIONS

The low waste gas levels of xenon seem to be beneficial compared to nitrous oxide.

Graphite whiskers in CV3 meteorites

Graphite whiskers (GWs), an allotrope of carbon that has been proposed to occur in space, have been discovered in three CV-type carbonaceous chondrites via Raman imaging and electron microscopy. The GWs are associated with high-temperature calcium-aluminum inclusion (CAI) rims and interiors, with the rim of a dark inclusion, and within an inclusion inside an unusual chondrule that bears mineralogy and texture indicative of high-temperature processing. Current understanding of CAI formation places their condensation, and that of associated GWs, relatively close to the Sun and early in the condensation sequence of protoplanetary disk materials. If this is the case, then it is a possibility that GWs are expelled from any young solar system early in its history, thus populating interstellar space with diffuse GWs. Graphite whiskers have been postulated to play a role in the near-infrared (near-IR) dimming of type Ia supernovae, as well as in the thermalization of both the cosmic IR and microwave background and in galactic center dimming between 3 and 9 micrometers. Our observations, along with the further possibility that GWs could be manufactured during supernovae, suggest that GWs may have substantial effects in observational astronomy.

[Anaesthesiology as a compulsory subject in the new German medical school curriculum. Evaluation of a curricular model at the University Hospital Aachen]

BACKGROUND

Since October 2003 new regulations for qualifications to practice medicine in Germany now require compulsory courses in anaesthesiology. Therefore, existing curricular activities had to be changed from facultative courses for a small number of interested students to compulsory activities for all students.

METHODS

Previous data of the department of anaesthesiology at the University Hospital Aachen (Germany) were collected and taken into consideration for the development of a new curriculum: The result was a course consisting of a tutorial with integrated "basic skill training", practical training in the operating theatre and a simulation-based session, in addition to two series of lectures. An evaluation by the students was carried out using EvaLuna as a tool for web-based on-line evaluation and faculty members had to fill out a standardized questionnaire.

RESULTS

The different parts of the curriculum received the highest scores of all courses in the undergraduate medical school curriculum. Best results were achieved by the anaesthesia-simulation session followed by the tutorial and the practical training.

CONCLUSION

The feedback of faculty members as well as the results of students' evaluation approved the developed concept of integrating anaesthesia-relevant issues into the formal medical school curriculum. Nevertheless, the on-line evaluation system EvaLuna provided additional suggestions for future improvements in the newly created curriculum.

Emergence and early cognitive function in the elderly after xenon or desflurane anaesthesia: a double-blinded randomized controlled trial †

BACKGROUND

Postoperative cognitive impairment after general anaesthesia, especially in the elderly, is a well-recognized problem. Xenon, known to be an N-methyl-d-aspartate antagonist, may be advantageous. In this study, the early cognitive function in the elderly after general anaesthesia with xenon was compared with that after desflurane.

METHODS

After approval by the local ethical committee and after obtaining written informed consent, patients were enrolled in this randomized, double-blinded, controlled study. Thirty-eight patients (65-75 yr old, ASA status I-III) undergoing an elective surgery with a planned duration of 60-180 min were allocated to either the xenon (n = 18) or the desflurane (n = 20) anaesthesia group. The primary outcome was the cognitive Test for Attentional Performance (TAP) with its subtests Alertness, Divided Attention, and Working Memory. After baseline assessment 12-24 h before operation, patients were followed-up 6-12 and 66-72 h after operation. Secondary outcomes were emergence times from anaesthesia and the modified Aldrete score.

RESULTS

No difference was found between the groups in the TAP at 6-12 and 66-72 h after operation. In the xenon group, emergence time was significantly faster for the following parameters: time to open eyes (P = 0.001), to react on demand (P = 0.001), to extubation (P = 0.001), and for time and spatial orientation (P = 0.007). The modified Aldrete score was significantly higher after 30, 45 and 60 min in the xenon group.

CONCLUSIONS

There was no difference in the postoperative cognitive testing at 6-12 and 66-72 h. Xenon was associated in the elderly with a faster emergence from general anaesthesia than desflurane.

HEPES-stabilized encapsulation of Salmonella typhimurium

Most bacteria, planktonic and sessile, are encapsulated inside loosely bound extracellular polymeric substance (EPS) in their physiological environment. Imaging a bacterium with its capsule requires lengthy sample preparation to enhance the capsular contrast. In this study, Salmonella typhimurium was investigated using atomic force microscopy for a practical means of imaging an encapsulated bacterium in air. The investigation further aimed to determine the relation between the buffers used for preparing the bacterium and the preservation of the capsular material surrounding it. It was observed that rinsing bacteria with HEPES buffer could stabilize and promote capsule formation, while rinsing with PBS, Tris, or glycine removes most of the capsular EPS. For bacteria rinsed with HEPES and air-dried, the height images showed only the contour of the capsular material, while the phase and amplitude images presented the detailed structures of the bacterial surface, including the flagella encapsulated inside the capsular EPS. The encapsulation was attributed to the cross-linking of the acidic exopolysaccharides mediated by the piperazine moiety of HEPES through electrostatic attraction. This explanation is supported by encapsulated bacteria observed for samples rinsed with N,N'-bis(2-hydroxyethyl)-piperazine solution and by the presence of entrapped HEPES within the dry capsular EPS suggested by micro-Raman spectroscopy.

Organics Captured from Comet 81P/Wild 2 by the Stardust Spacecraft

Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution in abundance and composition. Some organics are similar, but not identical, to those in interplanetary dust particles and carbonaceous meteorites. A class of aromatic-poor organic material is also present. The organics are rich in oxygen and nitrogen compared with meteoritic organics. Aromatic compounds are present, but the samples tend to be relatively poorer in aromatics than are meteorites and interplanetary dust particles. The presence of deuterium and nitrogen-15 excesses suggest that some organics have an interstellar/protostellar heritage. Although the variable extent of modification of these materials by impact capture is not yet fully constrained, a diverse suite of organic compounds is present and identifiable within the returned samples.

Infrared Spectroscopy of Comet 81P/Wild 2 Samples Returned by Stardust

Infrared spectra of material captured from comet 81P/Wild 2 by the Stardust spacecraft reveal indigenous aliphatic hydrocarbons similar to those in interplanetary dust particles thought to be derived from comets, but with longer chain lengths than those observed in the diffuse interstellar medium. Similarly, the Stardust samples contain abundant amorphous silicates in addition to crystalline silicates such as olivine and pyroxene. The presence of crystalline silicates in Wild 2 is consistent with mixing of solar system and interstellar matter. No hydrous silicates or carbonate minerals were detected, which suggests a lack of aqueous processing of Wild 2 dust.

Comet 81P/Wild 2 Under a Microscope

The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales.

Regulationsstörungen in der frühen Kindheit: Ergebnisse der Leipziger Beratungsstelle für Eltern mit Säuglingen und Kleinkindern

BACKGROUND

About 25 % of children in the first three years attract attention due to regulatory disorders like un-apeasable crying, chronic fussing, sleep- and feeding-disorders as well as excessive temper-tantrums. Meanwhile there are many counselling services in Germany, which provide help for parents.

PATIENTS

Data of 153 families with infants and toddlers till the age of three, who visited the Leipzig counselling service during a period of two years.

METHOD

Paediatric-neurodevelopmental status and extensive psychosocial anamnesis following a semi-structured interview-guideline.

RESULTS

74 % of the families attended one or two times, in 60 % of these cases an improvement or solution of the problem occurred. 18 % of the mothers showed depressive symptoms, which are linked to the absence of the partners on a highly significant level. 23 % of the families were acutely psycho-socially stressed; these families were neither able to use the offered interventions in an appropriate way, nor were others able to use it at all.

CONCLUSIONS

The surveyed data support the assumption, that early childhood intervention provides help briefly and economically. For the relatively large group of "multi-problem families" in the sample we can not yet offer intervention strategies, which could help these children to reduce their high developmental risk.

[Neuromonitoring with S-100 protein in the intensive care unit]

During the last years biochemical neuromonitoring with various molecules such as S-100 protein has become popular. A huge number of investigations both experimental and clinical have been undertaken to determine diagnosis and prognosis of patients with acute neurologic diseases. This article gives a review on the current knowledge, indications and limitations on the use of S-100 protein with regard to most of the acute neurological diseases an intensivist is confronted with in everyday practice.