Cardiogenic oscillations to detect intratidal derecruitment and overdistension in a porcine model of healthy and atelectatic lungs.

BACKGROUND: Low positive end-expiratory pressure (PEEP) can result in alveolar derecruitment, and high PEEP or high tidal volume (VT) in lung overdistension. We investigated cardiogenic oscillations (COS) in the airway pressure signal to investigate whether these oscillations can assess unfavourable intratidal events. COS induce short instantaneous compliance increases within the pressure-volume curve, and consequently in the compliance-volume curve. We hypothesised that increases in COS-induced compliance reflect non-linear intratidal respiratory system mechanics. METHODS: In mechanically ventilated anaesthetised pigs with healthy (n=13) or atelectatic (n=12) lungs, pressure-volume relationships and the ECG were acquired at a PEEP of 0, 5, 10, and 15 cm H2O. During inspiration, the peak compliance of successive COS (CCOS) was compared with intratidal respiratory system compliance (CRS) within incremental volume steps up to the full VT of 12 ml kg-1. We analysed whether CCOS variation corresponded with systolic arterial pressure variation. RESULTS: CCOS-volume curves showed characteristic intratidal patterns depending on the PEEP level and on atelectasis. Increasing CRS- or CCOS-volume patterns were associated with intratidal derecruitment with low PEEP, and decreasing patterns above 6 ml kg-1 and high PEEP showed overdistension. CCOS was not associated with systolic arterial pressure variations. CONCLUSIONS: Heartbeat-induced oscillations within the course of the inspiratory pressure-volume curve reflect non-linear intratidal respiratory system mechanics. The analysis of these cardiogenic oscillations can be used to detect intratidal derecruitment and overdistension and, hence, to guide PEEP and VT settings that are optimal for respiratory system mechanics.

Determination of respiratory system mechanics during inspiration and expiration by FLow-controlled EXpiration (FLEX): a pilot study in anesthetized pigs.

BACKGROUND: Differences between inspiratory and expiratory lung mechanics result in the hysteresis of the pressure volume-loop. While hysteresis area is a global parameter describing the difference between inspiration and expiration in mechanics under quasi-static conditions, a detailed analysis of this difference under the dynamic conditions of mechanical ventilation is feasible once inspiratory and expiratory compliance (Cin/Cex) are determined separately. This requires uncoupling of expiratory flow rate and volume (V). METHODS: Five piglets were mechanically ventilated at positive end-expiratory pressure (PEEP) levels ranging from 0 to 15 cmH2O. Expiratory flow rate was linearized by a computer-controlled resistor (flow-controlled expiration). The volume-dependent Cin(V) and Cex(V) profiles were calculated from the tracheal pressure volume-loops. RESULTS: The intratidal curve-progression of Cex(V) was altogether higher with a steeper slope compared to Cin(V). With increasing positive end-expiratory pressure (PEEP) dynamic hysteresis area decreased and Cex(V) tended to run more parallel to Cin(V). CONCLUSION: The relation between inspiratory and expiratory compliance profiles is associated with the hysteresis area and behaves PEEP dependent. Analysing the Cin-Cex-relation might therefore potentially offer a new approach to titrate PEEP and tidal volume.

Haemodynamic stability and pulmonary shunt during spontaneous breathing and mechanical ventilation in porcine lung collapse.

BACKGROUND: We investigated the haemodynamic stability of a novel porcine model of lung collapse induced by negative pressure application (NPA). A secondary aim was to study whether pulmonary shunt correlates with cardiac output (CO). METHODS: In 12 anaesthetized and relaxed supine piglets, lung collapse was induced by NPA (-50 kPa). Six animals resumed spontaneous breathing (SB) after 15 min; the other six animals were kept on mechanical ventilation (MV) at respiratory rate and tidal volume (V(T) ) that corresponded to SB. All animals were followed for 135 min with blood gas analysis and detailed haemodynamic monitoring. RESULTS: Haemodynamics and gas exchange were stable in both groups during the experiment with arterial oxygen tension (PaO(2) )/inspired fraction of oxygen (FiO(2) ) and pulmonary artery occlusion pressure being higher, venous admixture (Q(va) /Q(t) ) and pulmonary perfusion pressure being lower in the SB group. CO was similar in both groups, showing slight decrease over time in the SB group. During MV, Q(va) /Q(t) increased with CO (slope: 4.3 %min/l; P < 0.001), but not so during SB (slope: 0.55 %min/l; P = 0.16). CONCLUSIONS: This porcine lung collapse model is reasonably stable in terms of haemodynamics for at least 2 h irrespective of the mode of ventilation. SB achieves higher PaO(2) /FiO(2) and lower Q(va) /Q(t) compared with MV. During SB, Q(va) /Q(t) seems to be less, if at all, affected by CO compared with MV.

Guidelines for safety and quality in anaesthesia practice in the European Union.

Anaesthesia is a medical specialty that is particularly concerned with the safety of the patient who is undergoing a surgical procedure. This is a prerequisite in order to provide quality of care, which is based on good clinical practice, on a sound organization, on an agreement on best practice and on adequate communication with other healthcare workers involved. Providing a safe environment for those working in healthcare is at least as important as other factors serving that objective. A working party on Safety and Quality in Anaesthesiological Practice in the Section and Board of Anaesthesiology of the European Union of Medical Specialists (EUMS/UEMS) has prepared guidelines that were amended and approved recently.

[Perioperative treatment after esophagogastric surgery]. / Tapasztalataink nyelócsó- és kiterjesztett gyomormútétes betegek perioperatív kezelésében.

Extended gastric and esophageal resection is still associated with high postoperative morbidity and mortality. We performed a retrospective analysis of the perioperative management of 72 patients who had undergone such operations during a one-year period. Patient and management variables were analyzed by multivariate statistical methods to identify pre-, intra-, and postoperative factors which influence the results. The investigation of preoperative data revealed an increase of esophageal cancer among younger (< 55 years) patients (12 patients underwent gastrectomy and 22 esophageal resection). The intensity of smoking was significantly higher compared to the elderly (11.27 vs. 7.4 cigarettes/day; p < 0.05); and the same applies to alcohol consumption. In older patients (> 55 years of age), the duration of postoperative artificial ventilation was significantly longer (10.1 vs. 4 hours, p < 0.05) and the prevalence of septic complication was higher, than in younger patients. All three postoperative deaths recorded in this series occurred in the group of elderly patients. A preoperative weight loss exceeding 10 per cent of body weight was associated with significantly longer postoperative stay (21.6 vs. 17.4 days; p < 0.001), as well as with need for longer parenteral feeding (13.05 vs. 10.06 days; p < 0.005). Operations longer than 6 hours were associated with significantly longer postoperative ventilation period (14.44 vs. 5.31 hours; p < 0.02), need for longer stay intensive care unit (10.56 vs. 6.55 days; p < 0.001) and longer postoperative stay (21.56 vs. 17.64 days; p < 0.05). The prevalence of pulmonary complications was connected to the duration of the operation (10/16 vs. 3/55). We also describe and analyse two contemporary methods designed for monitoring circulatory parameters (PICCO) and tissue oxygenation (gastrotonometry). The analysis of postoperative data demonstrates that postoperative pain control with continuous epidural analgesia is superior to methods as it shortens the length of stay on the intensive care unit (7.15 vs. 10.67 days; p < 0.05) and postoperative hospitalisation (18.06 vs. 23.50 days; p < 0.05). Nutritional support is essential after esophageal anastomosis till oral feeding can start. Enteral nutrition was given through a jejunal tube that had been inserted intraoperatively. Calorie intake was built up step by step to a maintenance level of 31.2 kcal/day, which was administered until oral feeding could be started (mean duration 10.94 days; maximum duration: 42 days). We conclude that careful selection of patients, appropriate intra- and postoperative management, with adequate postoperative pain control can reduce postoperative morbidity and length of inpatient stay.

[Vascular tunnel creation to improve the effect of decompressive craniectomy in severe traumatic cerebral edema]. / Vascularis alagútképzés mint új mütéti módszer a decompressiv craniectomia hatásának fokozására, súlyos, traumás agyduzzadás esetén.

More than million people/year die after head injury. The cause of death in 50% is the secondary brain swelling with incuneation. Today decompressive craniectomy with durotomy for traumatic brain swelling is performed as second--tier therapy at many clinics and hospitals. The literature mentions this method only as an option. The problem so far existed in the following fact: although the above mentioned method successfully diminished the ICP still despite this result, partial or total lesion occurred in the herniated part of the brain. The actual cause of these symptoms is found in the blockage of the veins and arteries, caused by shearing and compressive forces between the dural edge and brain tissue. Venous congestion induces further edema in the protruding parts of the brain, thus causing lesion by strangulated necrosis and hypoxia. The new surgical technique consists of a stellate manner durotomy and of creating a vascular tunnel by supporting pilasters made of haemostatic sponge around the main cortical veins and arteries of herniated brain. With the help of new technique the authors managed not only to reduce the intracranial pressure significantly but they could avoid further edema and vascular lesion as well. This due to the fact that with this method we assure the blood circulation and venous drainage of the herniated part of the brain. We think, that in this case despite of the initially severe status, the properly indicated combination of craniectomy, durotomy and vascular tunnel creation, could be the main factor of the surprisingly favorable outcome.

A catheter technique in ophthalmic regional anaesthesia. Cadaver experiments.

BACKGROUND: Regional anaesthesia for ophthalmic surgery is generally accomplished by peri- or retrobulbar techniques. Depending on the duration of ophthalmic surgery, reblock might become necessary. Our goal was to invent a catheter technique for ophthalmic regional anaesthesia that enables the user to administer local anaesthetics intraoperatively into the peri- or retrobulbar space continuously. METHODS: Twenty-five adult cadaver orbits of normal size and anatomy were used for the experiments. A flexible catheter was introduced transcutaneously or transconjunctivally into the extra- or intraconal space. Methylene blue solution was injected through the catheter. RESULTS: Using the same transcutaneous retro- and peribulbar technique, it was possible to introduce flexible catheters into a proper position of the cadaver orbits. The injected dye was found intra- or extraconally. CONCLUSION: Examining the spread of the dye in the orbit, we concluded that it is possible to provide ophthalmic anaesthesia for surgery through an indwelling catheter. We proved that continuous or intermittent administration of a local anaesthetic agent into the extra- or inraconal space can be achieved and this technique may allow us to maintain anaesthesia as long as it is necessary.

A catheter technique in ophthalmic regional anaesthesia. Clinical investigations.

BACKGROUND: Usually general anaesthesia is chosen if ophthalmic surgery of longer duration is expected. Our goal was to introduce a flexible catheter preoperatively into the extra- or intraconal space and to provide sufficient anaesthesia by continuous administration of a local anaesthetic via the catheter. METHODS: The continuous anaesthetic technique was applied in 28 patients undergoing vitreoretinal surgery. An indwelling catheter was introduced in 20 patients into the intraconal and in 8 patients into the extraconal space. In 6 patients, the position of the catheter was controlled by ultrasound examination prior to the injection of the local anaesthetic agent. RESULTS: For all patients adequate anaesthesia could be achieved and maintained with continuous retrobulbar administration (CRA) of a local anaesthetic by catheter. There were two patients who experienced moderate pain intraoperatively during continuous peribulbar administration (CPA). No complications occurred with the placement of the catheters. The catheter did not disturb the surgeon or the process of the ophthalmic surgery. CONCLUSIONS: Continuous administration of a local anaesthetic agent via an indwelling catheter into the intraconal space allowed ophthalmic anaesthesia without time restriction. Thus, CRA is a good alternative to general anaesthesia for patients undergoing long-lasting ophthalmic surgery.

[Anesthesia ambulatory one-day surgery]. / Erzéstelenítés egynapos, ambuláns sebészeti beavatkozások során.

The spreading of the cost-benefit attitude is a considerable help in the progress of the one day surgery. The patient selection, the preoperative patient preparations and the preoperative examination has done in the anaestesiologic ambulance. Aims of ambulatory anaesthesia are to achieve sedation, hypnosis, analgesia, amnesia and muscle relaxation during the operation, to preserve preoperative mental and physiologic state, analgesia and to make early postoperative nourishing possible. Besides personnel and equipment of anaesthesia and reanimation, monitoring of circulation, respiration and neuromuscular transmission is needed. Anaesthetic methods: local, regional and general anaesthesia or sedation. Ways of general anaesthesia are intravenous, inhalation or combined. Intravenous anaesthetic drugs (barbiturates, ketamine, etomidate, midazolam, propofol and eltanolon) can be used in monotherapy or in combination with each other or opioids (morphine, alfentanil, fentanyl, sufentanil, remifentanil). Among inhalatic agents N2O isoflurane, desflurane, sevoflurane are advisable. Recommended non depolarising muscle relaxants are the short-acting atracurium, mivacurium, vecuronium and rocuronium. Methods for loco-regional anaesthesia are infiltration, peripheral nerve blockade, epidural and intradural anaesthesia which can be used with additional vigil sedation. Blockades with local analgetics, intraoperative opioids, non-steroid anti-inflammatory drugs, sedatives, pre-emptiv analgesia and patient controlled analgesia can be used for postoperative pain relief. Besides the patient and intervention type selection the adequate perioperative anaesthesiologic work and the prudent specifications of leaving conditions is the most important terms of the safety of one-day surgery and anaesthesia.

[Postoperative percutaneous endoscopic gastrostomy/jejunostomy]. / A postoperativ szakban készített percutan endoscopos gastrostoma/jejunostoma.

In order to cure complications appeared in the postoperative period two patients were treated with percutaneous endoscopic gastrostomy/jejunostomy (PEG, PEGJ) with the purpose of long-lasting enteral feeding and decompression. The indications of PEG/PEGJ were the following: external gastric fistula in one case and anastomotic leakage in one case. In the patients the PEG was located by intraoperative X-ray examination, this method was not published earlier. Regarding complications of the early postoperative period the PEG and the PEGJ are considered useful and expedient procedures with the aim of lasting enteral feeding and decompression.

Expression of inositol 1,4,5-trisphosphate receptors in rat adrenocortical zones.

Previously we demonstrated the presence of InsP3R-I, -II and -III subtypes in the zona glomerulosa. Now we have examined the expression of different subtypes of inositol 1,4,5-trisphosphate receptor (InsP3R) in the inner zones of rat adrenal cortex. RNA extracted from decapsulated adrenal tissue (zonae fasciculata-reticularis and the medulla) or from fasciculata-reticularis cells was reverse transcribed. Subsequent polymerase chain reaction revealed the presence of InsP3R-I, -II and -III subtypes in decapsulated tissue but failed to demonstrate the expression of any known subtypes of InsP3R in fasciculata-reticularis cells. Accordingly, InsP3 receptors expressed in the decapsulated tissue are of medullary origin.

Impact of single neonatal allylestrenol treatment on the estrus cycle of rats treated with FSH+LH or TSH.

Neonatal allylestrenol treatment administered to female rats significantly increases the duration of estrus phase in the sexual cycle. Treatment with follicle stimulating hormone (FSH) + luteinizing hormone (LH) in adulthood prolongs the duration of estrus even on its own; the effect, however, is more pronounced in those animals who were treated (imprinted) with allylestrenol neonatally. When administered to the control animals, the chemically related thyreotrop hormone (TSH) is either indifferent or it even decreases the estrus index. In animals having received neonatal allylestrenol treatment, however, TSH administration increases significantly the duration of the estrus phase. Either with or without FSH+LH treatment, the ratio of estrogenic to gestagenic phase increases following neonatal allylestrenol treatment. The experiments call attention to the potential functional risks inherent in neonatal allylestrenol treatment. The actual risks, however, seem to be smaller than the effects seen at the receptor level.

[Prevention of suture insufficiency using seromuscular gastric wall patch]. / Vorbeugung der Nahtinsuffizienz mit seromuskulärem Magenwand-Fleck.

Seromuscular patches were prepared from the wall of the resected stomach of 20 dogs. The patches were used in the form of allogeneic and autologous grafts fixed with Histoacryl adhesive to cover gastric and intestinal sutures and gastric perforations. The aim was a hermetic closure of the wound and the prevention of suture insufficiency. In the 7 to 90 days follow-up period a perfect organization was observed in all the cases. On the basis of the favourable experimental results the clinical application of autologous seromuscular patches is suggested.

[Covering the resected surface of parenchymatous organs with histoacryl-N-blue tissue adhesive and a seromuscular patch from the gastric wall]. / Bedeckung der Resectionsfläche von parenchymataösen Organen mit durch Histoacryl-N-Blau fixierten seromuskulären Fleck aus der Magenwand.

Seromuscular patches were prepared from the gastric wall of 20 experimental dogs and used in the form of autologous or allogenic transplants for the covering of the resection surface of parenchymal organs (liver, spleen, pancreas). The patches were fixed by means of the tissue adhesive Histoacryl-N-Blue; the aim was to achieve haemostasis and to prevent running of the secretion. In the 1 to 90 days follow-up period the patches completely organized and in none of the cases did haemorrhage occur. On the basis of the good experimental results the authors suggest the possibility of the clinical application of autologous patches.

Postoperative apnoea following nivalin administration.

Four patients developed postoperative apnoea after neuroleptanalgesia, and were given Nivalin whilst in an apnoeic state to reverse residual neuromuscular block. Neuromuscular transmission was monitored by a peripheral nerve stimulator, and recurarization was not observed. Central respiratory depression was the cause of postoperative apnoea. The possible mechanisms and the mode of prevention are stated in this paper.