Validation of a Simple Tool for Electronic Documentation of Behavioral Responses to Anesthesia Induction.

BACKGROUND: Anxiety and distress behaviors during anesthesia induction are associated with negative postoperative outcomes for pediatric patients. Documenting behavioral responses to induction is useful to evaluate induction quality at hospitals and to optimize future anesthetics for returning patients, but we lack a simple tool for clinical documentation. The Induction Compliance Checklist is a tool for grading induction behaviors that is well validated for research purposes, but it is not practical for routine documentation in busy clinical practice settings. The Child Induction Behavioral Assessment tool was developed to provide a simple and easy to use electronic tool for clinical documentation of induction behaviors. The aim of this study was to test the Child Induction Behavioral Assessment tool's concurrent validity with the Induction Compliance Checklist and the interrater reliability. METHODS: This prospective, observational study included 384 pediatric patients undergoing anesthesia inhalation induction. Concurrent validity with the Induction Compliance Checklist and interrater reliability of the Child Induction Behavioral Assessment were evaluated. Two researchers alternated scoring the Induction Compliance Checklist. The 2 researchers independently scored the Child Induction Behavioral Assessment. The anesthesia clinician caring for the patient also independently scored the Child Induction Behavioral Assessment by completing their routine documentation in the patient's medical record. Two age groups were evaluated (ages 1-3 and 4-12 years old). RESULTS: Clinicians' and researchers' Child Induction Behavioral Assessment scores demonstrated a strong correlation with the Induction Compliance Checklist (P < .0001). There was an excellent agreement between the 2 researchers' Child Induction Behavioral Assessment scores for the younger and older age groups, respectively (Kappa [95% CI] = 0.97 (0.94-0.99); K = 0.94 (0.89-0.99)]. The agreement between the researchers and the 117 clinicians who documented Child Induction Behavioral Assessment assessments in the medical record was good overall (intraclass correlation coefficient = 0.70), with fair agreement with the 1- to 3-year-old patients (intraclass correlation coefficient = 0.56) and good agreement for the 4- to 12-year-old patients (intraclass correlation coefficient = 0.74). CONCLUSIONS: The Child Induction Behavioral Assessment scale is a simple and practical electronic tool used to document pediatric behavioral responses to anesthesia inductions. This study provides evidence of the tool's validity and reliability for inhalation inductions. Future research is needed at other hospitals to confirm validity.

Volatiles or TIVA: Which is the standard of care for pediatric airway procedures? A pro-con discussion.

Anesthesia for pediatric airway procedures constitutes a true art form that requires training and experience. Communication between anesthetist and surgeon to establish procedure goals is essential in determining the most appropriate anesthetic management. But does the mode of anesthesia have an impact? Traditionally, inhalational anesthesia was the most common anesthesia technique used during airway surgery. Introduction of agents used for total intravenous anesthesia (TIVA) such as propofol, short-acting opioids, midazolam, and dexmedetomidine has driven change in practice. Ongoing debates abound as to the advantages and disadvantages of volatile-based anesthesia versus TIVA. This pro-con discussion examines both volatiles and TIVA, from the perspective of effectiveness, safety, cost, and environmental impact, in an endeavor to justify which technique is the best specifically for pediatric airway procedures.

Comparison of the effects of a dexmedetomidine-ketamine-midazolam anesthetic protocol versus isoflurane inhalation anesthesia on echocardiography variables and plasma cardiac troponin I concentration in black-tailed prairie dogs (Cynomys ludovicianus).

OBJECTIVE: To compare the effects of a dexmedetomidine-ketamine-midazolam (DKM) anesthetic protocol versus isoflurane inhalation anesthesia on echocardiographic variables and plasma cardiac troponin 1 (cTnI) concentration in black-tailed prairie dogs (BTPDs; Cynomys ludovicianus). ANIMALS: Nine 6-month-old sexually intact male captive BTPDs. PROCEDURES: Each BTPD was randomly assigned to be anesthetized by IM administration of dexmedetomidine (0.25 mg/kg), ketamine (40 mg/kg), and midazolam (1.5 mg/kg) or via inhalation of isoflurane and oxygen. Three days later, each BTPD underwent the alternative anesthetic protocol. Echocardiographic data and a blood sample were collected within 5 minutes after initiation and just prior to cessation of each 45-minute-long anesthetic episode. RESULTS: Time or anesthetic protocol had no significant effect on echocardiographic variables. For either protocol, plasma cTnI concentration did not differ with time. When administered as the first treatment, neither anesthetic protocol significantly affected plasma cTnI concentration. However, with regard to findings for the second treatments, plasma cTnI concentrations in isoflurane-treated BTPDs (n = 4; data for 1 animal were not analyzed because of procedural problems) were higher than values in DKM-treated BTPDs (4), which was suspected to be a carryover effect from prior DKM treatment. CONCLUSIONS AND CLINICAL RELEVANCE: The DKM and isoflurane anesthetic protocols did not have any significant effect on echocardiographic measurements in the BTPDs. Increases in plasma cTnI concentration during the second anesthetic episode were evident when BTPDs underwent the DKM anesthetic protocol as the first of the 2 treatments, suggestive of potential myocardial injury associated with that anesthetic protocol. Clinicians should consider these findings, especially when evaluating BTPDs with known or suspected cardiac disease.

Halving the volume of AnaConDa: initial clinical experience with a new small-volume anaesthetic reflector in critically ill patients-a quality improvement project.

AnaConDa-100 ml (ACD-100, Sedana Medical, Uppsala, Sweden) is well established for inhalation sedation in the intensive care unit. But because of its large dead space, the system can retain carbon dioxide (CO2) and increase ventilatory demands. We therefore evaluated whether AnaConDa-50 ml (ACD-50), a device with half the internal volume, reduces CO2 retention and ventilatory demands during sedation of invasively ventilated, critically ill patients. Ten patients participated in this cross-over protocol. After sedation with isoflurane via ACD-100 for 24 h, the 5-h observation period started. During the first hour, ACD-100 was used; for the next 2 h, ACD-50; and for the last 2 h, ACD-100 was used again. Sedation was titrated to Richmond Agitation and Sedation Scale (RASS) score - 3 to - 4 and a processed electroencephalogram (Narcotrend Index, Narcotrend-Gruppe, Hannover, Germany) was recorded. Minute ventilation, CO2 elimination, and isoflurane consumption were compared. All patients were deeply sedated (Narcotrend Index, mean ± SD: 38 ± 10; RASS scores - 3 to - 5) and breathed spontaneously with pressure support throughout the observation period. Infusion rates of isoflurane and opioid, either remifentanil or sufentanil, as well as ventilator settings were unchanged. Minute ventilation and end-tidal CO2 were significantly reduced with the ACD-50, respiratory rate remained unchanged, and tidal volume decreased by 66 ± 43 ml. End-tidal isoflurane concentrations were also slightly reduced while haemodynamic measures remained constant. The ACD-50 reduces the tidal volume needed to eliminate carbon dioxide without augmenting isoflurane consumption.

The Anesthesia Workstation: Quo Vadis?

Ensuring adequate ventilation and oxygenation and delivering inhaled anesthetic agent to the patient remain core responsibilities of the anesthesia provider during general anesthesia. Because of the emphasis placed on physiology, pharmacology, clinical sciences, and administrative duties, the stellar anesthesia workstation technology may be underutilized by the anesthesia community. Target-controlled O2 and agent delivery and automated end-expired CO2 control have entered the clinical arena, with only cost, luddism, and administrative hurdles preventing their more widespread use. This narrative review will explain technological aspects of existing and recently introduced anesthesia workstations. Concepts rather than particular anesthesia machines will be addressed, but examples will mostly pertain to the more recently introduced workstations. The anesthesia workstation consists of a ventilator, a carrier gas and agent delivery system, a scavenging system, and monitors. Mainly, the circle breathing circuit configuration, ventilator, and carrier gas and agent delivery technology are discussed. Occasionally, technical details are provided to give the reader a taste of the modern technology.

Evaluation of the anaesthetic depth during piglet castration under an automated isoflurane-anaesthesia at farm level.

Piglet castration under isoflurane-anaesthesia could represent an alternative to the practice of castration without anaesthesia. The objective of this study was to evaluate practicality and effectiveness of an automated isoflurane-anaesthesia for castration. A field study on three different farms in Germany (farm A, B: 200 sows; C: 540 sows) was performed. In total, 1429 (1166 anaesthetised and 263 conventionally castrated) male piglets (age: 1-8 days; bodyweight: 0.7-3.7 kg) were monitored. All piglets were treated with nonsteroidal anti-inflammatory drugs directly before castration. Castration and anaesthesia were performed by the farm-manager in presence of a veterinarian. All farmers used the PIGNAP Pro® (Agrosystems GmbH, CH) anaesthetic device (5 vol.% isoflurane, 30% oxygen; flow rate: 2 l/min). Vocalisation and defensive movements of 1166 anaesthetised piglets was rated using a scoring system. Presence or absence of the palpebral- and flexor-reflex was noted. Approximately every second piglet was weighed and oxygen-saturation and pulse- frequency of 231 animals were measured during treatment. Rectal temperatures before and after castration of 264 anaesthetised and 263 conventionally castrated piglets were compared. Only 77% of the anaesthetised piglets showed a sufficient anaesthetic depth based on the assessment of reflexes as well as vocalisations and defensive movements. It was found that the probability for a sufficient depth of anaesthesia decreases with increasing age and weight. The measurements of the pulse-frequency and oxygen-saturation showed an average oxygen-saturation of 98% and an average heart rate of 270/min during anaesthesia. The conventionally castrated piglets had significantly higher rectal temperatures in comparison to the anaesthetised (p < 0.0001). The result of 77% sufficiently anaesthetised piglets is not adequate for commercial application of this technology.

Using screen-based simulation of inhaled anaesthetic delivery to improve patient care.

Screen-based simulation can improve patient care by giving novices and experienced clinicians insight into drug behaviour. Gas Man(®) is a screen-based simulation program that depicts pictorially and graphically the anaesthetic gas and vapour tension from the vaporizer to the site of action, namely the brain and spinal cord. The gases and vapours depicted are desflurane, enflurane, ether, halothane, isoflurane, nitrogen, nitrous oxide, sevoflurane, and xenon. Multiple agents can be administered simultaneously or individually and the results shown on an overlay graph. Practice exercises provide in-depth knowledge of the subject matter. Experienced clinicians can simulate anaesthesia occurrences and practices for application to their clinical practice, and publish the results to benefit others to improve patient care. Published studies using this screen-based simulation have led to a number of findings, as follows: changing from isoflurane to desflurane toward the end of anaesthesia does not accelerate recovery in humans; vital capacity induction can produce loss of consciousness in 45 s; simulated context-sensitive decrement times explain recovery profiles; hyperventilation does not dramatically speed emergence; high fresh gas flow is wasteful; fresh gas flow and not the vaporizer setting should be reduced during intubation; re-anaesthetization can occur with severe hypoventilation after extubation; and in re-anaesthetization, the anaesthetic redistributes from skeletal muscle. Researchers using screen-based simulations can study fewer subjects to reach valid conclusions that impact clinical care.

[OPTIMIZATION OF PRECLINICAL TRAINING OF ANAESTHESIOLOGISTS BASED ON THE FORMATION OF PATHOGENIC SIMULATION LEARNING ENVIRONMENTS].

Simulation training has become an important component of the postgraduate training of anaesthesiologists for several reasons: organizational difficulties in obtaining primary professional skills in a clinical setting, the opportunity to study in a hospital existing pathology only and not planned in accordance with the curriculum. This increases the risk of medical malpractice of young specialist and study may be accompanied by complications and increasing the cost of treatment. In our work, we have studied the factors of continuity of preclinical and clinical stages of anaesthesiologists training in inhalation anaesthesia based on the use of modern simulation technologies. We compared the training programs and the results of traditional and simulation techniques, defined the concept of quasi physiology and propedeutics of robots and simulators, the role of clinical scenarios and reliability of robots of 6th level of realism in the formation of pathogenic environment for simulation training. In formulating the concept of pathogenetic simulation environment, we evaluated its impact on the motivation of the trainees of studied category. The study included 23 interns, divided approximately in half into 2 groups, the 1st of which at the preclinical stage of training was trained at the real operating theater gradually studying the technique of inhalation anaesthesia with an experienced curator The 2nd group studied the same anaesthesia in clinical scenarios of a simulator robot in a simulation operating theater Other components of the curriculum in the groups did not differ. According to the results of pre-clinical training interns started prforming an anaesthesia their self under the control of supervisor (i.e. to the clinical stage). In the 1st group, a supervisor made the verdict of readiness for clinical stage, and in the 2nd trainees were tested by the performing a robotic anaesthesia maintaining targeted qualitative and quantitative parameters. The evaluation was conducted according to the quality and stability criteria of five consecutive "independent" anaesthesia, where the highest scores were 100 points, confered by a supervisor. We found that for interns' admission to the clinical stage in the 1st group, it took significantly more educational anaesthesia than in 2nd group. It was also indirectly proved expectedly greater regularity and predictability of anesthesia simulation workshops. Based on the example of the clinical scenario of inhalation anesthesia we showed a possibility of formation of pathogenic simulation environment without excessive dramatization of studing environment, while maintaining the motivation of trainees. Thus, simulation training is more efficient than traditional schemes, in terms of providing the rational use of robotic systems of 6th level of realism.

Effects of inhalational anaesthesia with low tidal volume ventilation on end-tidal sevoflurane and carbon dioxide concentrations: prospective randomized study / Efectos de la anestesia inhalatoria con baja concentración final de volumen corriente de sevoflurano y dióxido de carbono: estudio prospectivo aleatorizado

Objective. We investigated how ventilation with low tidal volumes affects the pharmacokinetics of sevoflurane uptake during the first minutes of inhaled anaesthesia. Methods. Forty-eight patients scheduled for lung resection were randomly assigned to three groups. Patients in group 1, 2 and 3 received 3% sevoflurane for 3 min via face mask and controlled ventilation with a tidal volume of 2.2, 8 and 12 ml kg−1, respectively (Phase 1). After tracheal intubation (Phase 2), 3% sevoflurane was supplied for 2 min using a tidal volume of 8 ml kg−1 (Phase 3). Results. End-tidal sevoflurane concentrations were significantly higher in group 1 at the end of phase 1 and lower at the end of phase 2 than in the other groups as follows: median of 2.5%, 2.2% and 2.3% in phase 1 for groups 1, 2 and 3, respectively (P < 0.001); and 1.7%, 2.1% and 2.0% in phase 2, respectively (P < 0.001). End-tidal carbon dioxide values in group 1 were significantly lower at the end of phase 1 and higher at the end of phase 2 than in the other groups as follows: median of 16.5, 31 and 29.5 mmHg in phase 1 for groups 1, 2 and 3, respectively (P < 0.001); and 46.2, 36 and 33.5 mmHg in phase 2, respectively (P < 0.001). Conclusion. When sevoflurane is administered with tidal volume approximating the airway dead space volume, end-tidal sevoflurane and end-tidal carbon dioxide may not correctly reflect the concentration of these gases in the alveoli, leading to misinterpretation of expired gas data (AU)

Objetivo. Investigamos cómo la ventilación controlada con volúmenes corrientes bajos afecta a la farmacocinética del sevoflurano durante los primeros minutos de anestesia inhalada. Métodos. Cuarenta y ocho pacientes programados para cirugía de resección pulmonar fueron distribuidos al azar en tres grupos. Los pacientes del grupo 1, 2 y 3 recibieron sevoflurano al 3% durante 3 minutos mediante ventilación controlada a través de mascarilla con un volumen corriente de 2,2, 8 y 12 ml kg−1, respectivamente (Fase 1). Después de la intubación traqueal (Fase 2), se administró sevoflurano al 3% durante 2 minutos usando un volumen corriente de 8 ml kg−1 (Fase 3). Resultados. las concentraciones finales de sevoflurano fueron significativamente superiores en el grupo 1 al final de la fase I e inferiores al final de la fase II con respecto a los otros grupos: mediana del 2,5%, 2,2% y 2,3% en la fase I para los grupos 1, 2 y 3, respectivamente (P < 0,001), y 1,7%, 2,1% y 2,0% en la fase II, respectivamente (P < 0,001). Los valores de dióxido de carbono en el grupo 1 fueron significativamente inferiores al final de la fase I y superiores al final de la fase II frente a los otros grupos: mediana de 16,5, 31 y 29,5 mmHg en la fase I para los grupos 1, 2 y 3, respectivamente (P < 0,001), y 46,2 36, y 33,5 mmHg en fase II, respectivamente (P < 0,001). Conclusión. Cuando el sevoflurano se administra mediante volúmenes corrientes cercanos al volumen de espacio muerto de la vía aérea, las concentraciones finales de sevoflurano y dióxido de carbono pueden no reflejar correctamente la concentración de estos gases en los alvéolos, lo que puede conducir a una interpretación incorrecta de los gases expirados (AU)

[Practice guidelines for management of the difficult airway: update by the American Society of Anesthesiologists task force]. / "Practice Guidelines for Management of the Difficult Airway" : Update der American Society of Anesthesiologists Task Force.

In February 2013 the Committee of the American Society of Anesthesiologists (ASA) Task Force published the amended version of the "Practice guidelines for management of the difficult airway" which replace the recommendations from 2003. The amended version re-evaluated the recommendations from 2003 in 2011, evaluated recently published studies and recommendations and included them in the new practice guidelines. In particular, new technical developments, such as the recently established video-assisted intubation procedure were taken into consideration. Despite the many publications in the field of airway management the evidence resulting from the data obtained from recent publications is so low that the new information does not necessitate any amendments to the existing guidelines. In short, the current guidelines basically correspond to the previous version published 10 years ago but are, however, more than twice as extensive. This article summarizes and comments on the cornerstones of the guidelines.

Technical communication: the effect of the double mask on anesthetic waste gas levels during pediatric mask inductions in dental offices.

A significant portion of office-based general anesthesia for pediatric patients is performed in dental offices and involves mask inductions with inhaled drugs. This can lead to significant pollution with waste gases. We assessed occupational exposure to anesthetic drugs during pediatric general anesthesia in dental offices and assessed the effectiveness of the "double mask." Nine freestanding dental offices had measurements of anesthetic waste gas levels taken before and immediately after implementation of a double-mask system. Levels of nitrous oxide decreased from a median of 40.0 parts per million (ppm; interquartile range [IQR] = 23.0-46.0 ppm, n = 9) to 3.0 ppm, (IQR = 2.3-4.7 ppm, n = 9, P = 0.0055) and exceeded 25 ppm in 0% of the 9 offices (upper 95% confidence limit 34%) when using the double mask. Levels of sevoflurane decreased from a median of 4.60 ppm (IQR = 3.10-7.00 ppm, n = 9) to 0 ppm (IQR = 0-0.39 ppm, n = 9, P = 0.0024) and exceeded 2 ppm in 0% of the 9 offices (upper 95% confidence limit 34%) when using the double mask. We demonstrated in our study that the double-mask system, when used with dental "high-volumes" suctions (high-volume evacuators producing approximately 12 m(3)/h) in freestanding dental offices, was sufficient to decrease the exposure to anesthetic waste gas during pediatric mask induction in at least two thirds of offices when compared with the traditional mask.

Anesthesia for children with mitochondrial disorders: a national survey and review.

PURPOSE: Mitochondrial diseases are a heterogeneous group of disorders. Patients with such diseases often need general anesthesia for diagnostic procedures and surgery; guidelines are lacking for the anesthetic care of these patients. METHODS: We conducted a survey to investigate the current practices of pediatric anesthesiologists in the US in order to determine and document current practice. The survey consisted of twenty questions, including two demographic questions. A link to the survey was sent via email to members of the Society for Pediatric Anesthesia (2440), and was available online for 14 weeks. RESULTS: Only 503 completed the survey: a response rate of 20.61 %. Among the responders, 93.2 % had children with mitochondrial disorders among their patients, but only 11 % had institutional guidelines for such cases in place. Among the responders, 80.3 % used the standard nil per os (NPO) status guidelines, while the rest give intravenous dextrose solution once NPO was in effect. Only 18.3 % took precautions for malignant hyperthermia during treatment. The majority of the practitioners chose sevoflurane as the safest inhaled agent for induction and maintenance (89.7 and 78.5 %, respectively). Regional anesthesia was deemed safe by 97.3 % of the responders. Lactated Ringer's solution was considered safe for these children by 49 %; only 47.8 % used dextrose-containing fluids for fluid replacement. The blood glucose was monitored by 72.7 %, and the majority (85 %) of this monitoring was done in a postanesthesia care unit. CONCLUSION: Although the response rate was low, the majority of the responders provide care to these children routinely, so it can be inferred that the results of this survey are the closest published results to the true trend.

[Spanish Society of Anaesthesia (SEDAR) guidelines for pre-anaesthesia checking procedures]. / Directrices de procedimientos de comprobación y validación («chequeo¼) previos a la anestesia de la Sociedad Española de Anestesiología.

We present this document as a guide to preparing a specific institutional pre-anaesthesia checklist, as recommended in the Helsinki declaration on patient safety in anaesthesiology. Also, the recently recommended WHO "safe surgery check-list" includes a check-list for anaesthesia. A working group was established in accordance with the charter of the Spanish Society of Anaesthesiology and Resuscitation (Sociedad Española de Anestesiología y Reanimación [SEDAR]). The new patient safety culture introduced into medicine, and the recommendations of European anaesthesia societies has led us to design and update protocols in order to improve results in this important part of our speciality. We have prepared these recommendations or guidelines using, as examples, updates of pre-anaesthesia check-lists by other American (ASA), British, or Canadian societies of anaesthesia. With that aim, we enlisted the help of anaesthesia ventilator experts and the participation and advice of experienced anaesthesiologists from all parts of Spain. After various corrections and modifications, the document was available at www.sedar.es, so that any anaesthesiologist could propose any correction, or give their opinion. Finally, these guidelines have been approved by the SEDAR Board of Directors, before it was sent for publication in this journal. The aims of this document are to provide: a guideline applicable to all anaesthesia machines, a descriptive pre-anaesthesia check-list that include everything necessary for the anaesthesia procedure, and a resumed check-list to be available in all the anaesthesia machines or other equivalent, but prepared for each institution, which should include anaesthetic equipment and drugs. So, in order to ensure the aims and requirements of the European Board of Anaesthesiology, the European Society of Anaesthesiology, and the WHO are met, each institution should have a protocol for checking equipment and drugs. These guidelines are applicable to any anaesthesia equipment, enabling every institution to develop their own checking protocols, adapted to their anaesthesia machines and their procedures. With the consent of the SEDAR, this group will collaborate with anaesthesia machines providers in order to develop specific checklists for each of their models that will be available at www.sedar.es.

Nitrous oxide-oxygen administration: when safety features no longer are safe.

BACKGROUND: Nitrous oxide-oxygen sedation is used widely in dentistry because of its relative safety and efficacy. The most important safety consideration is the prevention of hypoxia. Safety features have been designed to prevent hypoxia by ensuring a minimal oxygen flow, thus limiting the amount of nitrous oxide that can be administered. METHODS: The authors review the 12 safety features used to ensure the safety and efficacy of nitrous oxide-oxygen sedation. They provide examples of safety feature failures, as well as steps to follow to help prevent negative outcomes. CONCLUSIONS: Nitrous oxide-oxygen delivery systems typically are limited to a maximum of 70 percent nitrous oxide and 30 percent oxygen delivery, which ensures that the patient is receiving at least 9 percent more oxygen than found in ambient air. Other safety features stop the delivery of nitrous oxide if oxygen flow stops. The pin-index safety system prevents the accidental attachment of a nonoxygen tank to the oxygen attachment portal, and diameter-index systems help ensure that the appropriate gas flows through the appropriate tubing. Although these safety features are in place, dentists have reported incidents of hypoxia involving incorrect equipment installation or equipment damage. Practice Implications. If a safety feature failure is suspected during administration of nitrous oxide-oxygen sedation, the clinician should remove the face mask from the patient immediately.

Evaluation of carbon dioxide anaesthesia for the castration of male suckling piglets by stress hormone concentrations, behaviour and clinical factors.

The objective of this study was to examine the effect of an anaesthesia using 70% carbon dioxide and 30% oxygen on endocrine stress reaction, behaviour and clinical parameters of male suckling piglets during castration. One hundred and seventy one male piglets, three to five days of age, were allocated to two experiments. They were assigned either to the procedures control handling, control castration, handling under anaesthesia or castration under anaesthesia in each experiment. In Experiment 1, adrenaline and noradrenaline plasma concentrations were measured in blood samples taken before (-15 min) and after (immediately, 2 min) handling/castration. In Experiment 2, behavioural observations and clinical parameters such as heart and respiratory rate, oxygen saturation, reflexes and recovery time were assessed at several sampling times. Measurement of adrenaline and noradrenaline concentrations revealed an increase in all groups after handling/castration (p < 0.0167), but higher concentrations were seen in the anaesthetized groups (25 to 93 times) than in control groups (two to four times). The excessive endocrine reaction suggests that carbon dioxide inhalation causes a more stressful situation in piglets compared to castration without anaesthesia. Behavioural abnormalities, significant decreases in the heart rate, the respiratory rate and the oxygen saturation (p < or = 0.001) including a cardiac arrhythmia (extrasystoles) underline the impression that CO2 inhalation anaesthesia negatively affects animal welfare. Based on the results of this study, this anaesthetic method is unsuitable to reduce stress induced by castration. Further research on alternatives is necessary to ensure the well-being of the piglets during castration.