Successful treatment of a patient with ARDS after pneumonectomy using high-frequency oscillatory ventilation.

High frequency oscillatory ventilation (HFOV) was used in a patient who developed the acute respiratory distress syndrome 5 days following a right pneumonectomy for bronchogenic carcinoma. When conventional pressure-controlled ventilation failed to maintain adequate oxygenation, HFOV dramatically improved oxygenation within the first few hours of therapy. Pulmonary function and gas exchange recovered during a 10-day period of HFOV. No negative side effects were observed. Early use of HFOV may be a beneficial ventilation strategy for adults with acute pulmonary failure, even in the postoperative period after lung resection.

Neue Perspektiven der laparoskopischen Simulation: Vom Studententrainingslabor bis zur Stressevaluation

Hintergrund: Die Anwendung eines LapSim®-Trainingsmodells im Studententrainingslabor sowie die objektive Evaluation von Stress in einem virtuellen Operations-Szenario bieten neue Perspektiven der laparoskopischen Simulation. Methodik: Im Studententrainingslabor erfolgte bei 28 Probanden am LapSim® Virtual-Reality (VR)-Simulator in einem Trainingscurriculum, bestehend aus 9 Einheiten, die Erfassung von Lernkurven laparoskopischer Basisfertigkeiten sowie komplexer Prozesse. In einem virtuellen Operations-Szenario wurde des Weiteren bei 18 Chirurgen eine Stressevaluation mittels eines Sympathikografen vorgenommen und dabei die laparoskopische Fehler- und Komplikationsrate erfasst. Hierbei konn…

Weiterentwicklung der maschinellen Beatmung mit Hilfe des nichtlinearen Zweikompartimentmodells

Unter der folgenden Hypothese tragen die Modellstudien zur Weiterentwicklung der maschinellen Beatmung bei: Das nichtlineare Zweikompartimentmodell der Lunge eroffnet die Moglichkeit, die maschinelle Beatmung anhand der Modellparameter der beiden Lungenkompartimente einzustellen bzw. hierdurch zu steuern.

The Laryngeal Mask Airway: routine, risk, or rescue?

An�sthesie zur endovaskul�ren Therapie aortaler Aneurysmen Verfahren und perioperative Risiken

Die transvaskulare Plazierung endoluminaler Gefasprothesen mittels interventionell-radiologischer Methoden ist ein neues, minimal invasives Verfahren zur Therapie von Aortenaneurysmen. Wir analysierten retrospektiv die Praktikabilitat verschiedener Anasthesieverfahren, die pathophysiologischen Auswirkungen des Eingriffs und typische Risiken. Bei 19 Patienten mit Aneurysmen der infrarenalen (n=18) oder der thorakalen Aorta (n=1) wurden in 23 Eingriffen aortale Stentprothesen implantiert. Die Eingriffe erfolgten in Allgemeinanasthesie (AA: n=9), in Periduralanasthesie (PDA: n=8) oder Lokalanasthesie (LA: n=6) mit Analgosedierung. Trotz erhohten Uberwachungsaufwands in der Gruppe AA ergaben si…

Simulation of Metabolism for The Calculation of Enzyme Activities in Stress Metabolism

Abstract Using data of indirect calorimetry, total energy turnover as well as the rate of combustion of carbohydrates, fat and amino acids can be calculated. For the evaluation, simple standard procedures (4) are used. These procedures presume, that several assumptions are satisfied, e.g. a complete degradation of the energy delivering substrates and undisturbed enzyme activities. To be able to interprete also measurements, which are performed in the post-traumatic state as well as for estimation of the extent and consequences of reduced enzyme activities, a new method for the simulation of metabolism was developed. Hie underlying model considers a reduced activity of key enzymes and a swit…

Kontinuierlicher exspiratorischer Alkoholnachweis

The absorption of large volumes of irrigation fluid is a major problem in transurethral prostatic surgery (TUR-P). Various indicators have been tested to monitor fluid absorption with regard to continuous registration and sufficient accuracy. The volumetric fluid balance is not suitable as a routine method because of its inaccuracy. Easily accessible parameters are unspecific because of surgical bleeding (haematocrit [Hct]), or are interfered with by physiological counter-regulatory actions (serum sodium [Na] concentration). In 1986 Hulten et al. suggested adding 2% ethanol to the irrigation fluid as a marker and investigated it intermittently in the expired air with an alcohol-test applian…

The Measurement of Enzyme Activities in the Resting Human Polymorphonuclear Leukocyte — Critical Estimate of a Method

As a system for study, the isolated human polymorphonuclear leukocyte combines the advantages of a quasi-non-invasive preparation with a nearly complete complement of enzymes of carbohydrate and energy metabolism. However, small sample volumes and, in some cases, very low enzyme activities make high demands on sample processing, storage, and performance of continuous measurements, if the enzyme activities are to be measured with acceptable reproducibility. In the presented study several aspects of homogenization, storage, and continuous measurement were scrutinized, to identify critical steps and consider ways of optimizing the method. Polymorphonuclear leukocytes were separated from the bl…

Combined Epidural and General Anesthesia Prevents Excessive Oxygen Consumption Postoperatively

In the postoperative period patients are at risk of excessive oxygen consumption (VO2). However, patients suffering from cardiovascular disease may be unable to increase their oxygen transport capacity sufficiently and may be especially vulnerable to tissue hypoxia as part of the reaction to intraoperative stress. During the last 10 years contradictory results concerning the benefits of a combined epidural and light general anesthesia have been published. Some of the results indicate that postoperative catabolism maybe depressed and that the neuroendocrine response to stress may be inhibited by such a combined technique1,2. We studied the effect of a combined epidural and light general anes…

Two memorial congresses in tribute of Omar Prakash, MD, PhD

Both memorial congresses presented the large field of computing and technology in anaesthesia and intensive care. Many of the contributors were personal friends of Omar and the spirit of Dr. Omar Prakash was present during these congresses. Quite certainly, he would have enjoyed both of the two occasions. They proved that the idea Dr. Omar Prakash first sparked in early eighties, of international meetings for scientists to come to meet friends and interchange ideas, is going strong. In fact, people spontaneously reached agreement that this tradition of Memorial congresses should be continued in the future. Whenever such a congress is to be arranged, you will see it being announced in this v…

Nitrous oxide in abdominal surgery

Abstract Inhalation anaesthesia has traditionally been the method of choice for abdominal surgery. While most surgical interventions in the lower abdomen can be performed under regional anaesthesia, a general anaesthetic technique is frequently chosen for upper abdominal procedures. This explains the almost routine use of nitrous oxide (N 2 O) for abdominal surgery. In addition to well-known contra-indications such as ileus and abdominal wall defects in infants, there is substantial scientific evidence against the application of N 2 O in abdominal surgery. N 2 O has an important role in the development of post-operative nausea and vomiting (PONV).

Temporal dynamics of lung aeration determined by dynamic CT in a porcine model of ARDS

We used dynamic CT to identify two different time constants of lung aeration and their individual contribution to the total increase in cross-sectional lung area in healthy and experimentally damaged lungs. In five healthy pigs, inflation and deflation between 0 and 50 cm H2O was imposed during dynamic (250 ms/image) CT acquisition, and repeated after experimental lung injury by saline lavage. The fractional areas of density ranges, which represent aerated lung parenchyma, were determined planimetrically, and their time for expansion during the manoeuvre was fitted using a bi-exponential model. Thus, two compartments, their sizes, i.e. their relative contributions to lung area aerated by th…

Automated anaesthesia record systems, observations on future trends of development.

The introduction of electronic anaesthesia documentation systems was attempted as early as in 1979, although their efficient application has become reality only in the past few years. Today, documentation technology is offered by most of the monitor manufacturers and new systems are being developed by various working groups. The advantages of the electronic protocol are apparent: Continuous high quality documentation, comparability of data due to the availability of a anaesthesia data bank, reduction of the workload of the anaesthesia staff and availability of new additional information. Disadvantages of the electronic protocol have also been discussed. Typically, by going through the proce…

Accuracy of delivered versus preset minute ventilation of portable emergency ventilators.

The accuracy of delivered minute volume (VE) ventilation of portable emergency ventilators (PEV) was evaluated. Five PEV from three manufacturers were adapted to an artificial lung for varying compliance and resistance. Each PEV was tested in the "no airmix" (pure oxygen) and "airmix" (approximately 60% oxygen) setting at different frequencies and VE. Measurement of delivered VE (VEdel) was made using a pneumotachograph and digital integration of the flow values greater than 1 min (maximal error +/- 2%). Maximal inspiratory pressure (Pinsp) was measured with a transducer. Two PEV from one manufacturer produced severe hyperventilation when used at low VE (i.e., in children). Two other PEV fr…

The AVL-mode: a safe closed loop algorithm for ventilation during total intravenous anesthesia.

The Adaptive Lung Ventilation Controller (ALV-Controller) represents a new approach to closed loop control of ventilation. It is based on a pressure controlled ventilation mode. Adaptive lung ventilation signifies automatic breath by breath adaptation of breathing patterns to the lung mechanics of an individual patient. The specific goals are to minimize work of breathing, to maintain a preset alveolar ventilation and to prevent the occurrence of intrinsic PEEP. We ventilated 5 patients undergoing major abdominal procedures using ALV. ALV was tolerated well in all patients. Alveolar ventilation was preset between 5500 and 6500 ml/min. Serial dead space (Vds) and respiratory time constant (r…

Laryngeal Mask Airway Position and the Risk of Gastric Insufflation

A potential risk of the laryngeal mask airway (LMA) is an incomplete mask seal causing gastric insufflation or oropharyngeal air leakage.The objective of the present study was to assess the incidence of LMA malpositions by fiberoptic laryngoscopy, and to determine their influence on gastric insufflation and oropharyngeal air leakage. One hundred eight patients were studied after the induction of anesthesia, before any surgical manipulations. After clinically satisfactory LMA placement, tidal volumes were increased stepwise until air entered the stomach, airway pressure exceeded 40 cm H2 O, or air leakage from the mask seal prevented further increases in tidal volume. LMA position in relatio…

Adaptive Lung Ventilation (ALV) Evaluierung eines neuen closed loop-gesteuerten Beatmungsalgorithmus bei Eingriffen in �berstreckter Seitenlage

The lateral decubitus position is the standard position for nephrectomies. There is a lack of data about the effects of this extreme position upon respiratory mechanics and gas exchange. In 20 patients undergoing surgery in the nephrectomy position, we compared a new closed-loop-controlled ventilation algorithm, adaptive lung ventilation (ALV), which adapts the breathing pattern automatically, to the respiratory mechanics with conventionally controlled mandatory ventilation (CMV). The aims of our study were (1) to describe positioning effects on respiratory mechanics and gas exchange, (2) to compare ventilatory parameters selected by the ALV controller with traditional settings of CMV, and …

Multirotations-CT während kontinuierlicher Beatmung: Vergleich unterschiedlicher Dichtebereiche bei gesunden Lungen und im Lavage-ARDS Modell

PURPOSE In this animal study, density ranges for CT-based quantification of ventilated lung area were determined. Healthy lungs and ARDS lungs were compared during artificial respiration. MATERIAL AND METHODS CT-scans were performed in 5 anesthetized pigs using a dynamic multiscan CT option on a predefined transverse slice (slice thickness 1 mm; effective temporal resolution, 250 ms). During continuous CT acquisition, airway pressure was increased or decreased in a stepwise manner. In all images, areas of defined HU ranges were determined planimetrically. The lower threshold was set to -910 HE in all images. The upper threshold was varied from -800 HE to -200 HE in steps of 100 HE. RESULTS …

Ein nichtlineares Zweikompartimentmodell der Lunge

Die Entwicklung, mathematische Beschreibung und Computersimulation des nichtlinearen Zweikompartimentmodells der Lunge sowie die Anpassung des Modells an Atemkurven von Patienten mit ARDS erfolgten in enger Zusammenarbeit mit Herrn Univ.-Prof. Dr. Beckmann und seinem Diplomanden Herrn Dany (Institut fur Physik, Abteilung fur nichtlineare Dynamik, Johannes Gutenberg-Universitat Mainz).

Computed tomography-based tracheobronchial image reconstruction allows selection of the individually appropriate double-lumen tube size

Objectives: To determine whether individualized selection of double-lumen tubes or alternatives based on three-dimensional reconstruction of the tracheobronchial image from routine preoperative computed tomography (CT) scans leads to clinically appropriate choices. Design: Prospective observational study; comparison to historic controls. Setting: Anesthesia and radiology facilities of a university medical center. Participants: Forty-nine patients undergoing thoracic surgery requiring one-lung ventilation. Interventions: Three-dimensional image reconstruction of individual tracheobronchial anatomy was performed from routine preoperative spiral CT scans as well as from scans of five left-side…

Assessment of Pulmonary Mechanics and Gastric Inflation Pressure During Mask Ventilation

AbstractIntroduction:Mask ventilation is a procedure routinely used in emergency medicine. Potential hazards are inadequate alveolar ventilation and inflation of the stomach with air, leading to subsequent regurgitation and aspiration. The aim of this study was to measure lung function and gastric inflation pressures during mask ventilation.Methods:For this purpose, 31 patients scheduled for routine urological procedures were studied during induction of anesthesia. Lung function was assessed by recording respiratory flow and pressure directly at the face mask. Gastric inflation was observed with a microphone taped to the epigastric area.Results:Gastric inflation occurred in 22 of the 31 pat…

Respiratory Mechanics, Gastric Insufflation Pressure, and Air Leakage of the Laryngeal Mask Airway

A potential risk of the laryngeal mask airway (LMA) is incomplete mask seal, which causes air leakage or insufflation of air into the stomach. The objective of the present study was to assess respiratory mechanics, quantify air leakage, and measure gastric air insufflation in patients ventilated via the LMA. Thirty patients were studied after induction of anesthesia but prior to any surgical manipulations. After the insertion of the LMA, patients were ventilated with increasing tidal volumes until one of the three following end points were reached: 1) gastric air insufflation, 2) airway pressure > 40 cm H2O, or 3) limitation of further increase in tidal volume by air leakage. The following …

High Degree of Realism in Teaching Percutaneous Coronary Interventions by Combining a Virtual Reality Trainer With a Full Scale Patient Simulator

The virtual reality coronary angiography simulator "CATHI" (Catheter Instruction System, Mannheim, Germany) simulates coronary arteries with implemented vessel lesions in virtual patients. Like similar systems the software model runs on common PC systems, which are linked to the mechanical device for manual training. We combined the advantages of this skill trainer with the near to reality assembly of a cardiac catheterization laboratory (Cath-lab) by connecting it to a full scale simulator (HPS, METI, Sarasota, FL). We present two methods of synchronizing the heartbeat between both simulation devices. Method A-the hardware solution-uses the electrocardiogram-synchronization signal of the H…

Externe Qualitätssicherung in der Anästhesie

Automatische Anästhesieprotokollsysteme

The introduction of electronic anaesthesia documentation systems was attempted as early as in 1979, although their efficient application has become reality only in the past few years. The advantages of the electronic protocol are apparent: Continuous high quality documentation, comparability of data due to the availability of a data bank, reduction in the workload of the anaesthetist and availability of additional data. Disadvantages of the electronic protocol have also been discussed in the literature. By going through the process of entering data on the course of the anaesthetic procedure on the protocol sheet, the information is mentally absorbed and evaluated by the anaesthetist. This i…

Investigation of Inspiratory Pressure-Volume Curves on Mechanically Ventilated Patients Using Least Square Polynomial Fit

Abstract An on-line method for the registration of pressure volume 1 oops TrT mechanically ventilated patients was developed using a personal computer with analog/digital interface. A third order polynomial function was fitted to the measured inspiratory pressure volume pairs. The significance of the fitting procedure was calculated using regression ANOVA. The inflection point of the pressure-volume curve was determinated by calculating the root of the second derivative of the polynomial. The method was teseted on 20 patients without major pulmonary dysfunction and on 6 patients with severe ARDS.

Changes of Hemodynamic Parameters, Pulmonary Gas Exchange, and Extravascular Lung Water During Esophageal Cancer Surgery

Esophagectomy is often connected to postoperative pulmonary complications with a high mortality rate [1, 3,4]. From 1980 to 1985 we treated 19 patients after esophagectomy in our intensive care unit. Nine patients (47%) died of pulmonary complications. From the literature [3] and from our own observations we came to the conclusion that the first pulmonary changes start during the operative procedure.