Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery: Guidelines of the German Society of Anaesthesiology and Intensive Care Medicine in collaboration with the German Association of the Scientific Medical Societies.

Haemodynamic monitoring and management are cornerstones of perioperative care. The goal of haemodynamic management is to maintain organ function by ensuring adequate perfusion pressure, blood flow, and oxygen delivery. We here present guidelines on "Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery" that were prepared by 18 experts on behalf of the German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und lntensivmedizin; DGAI).

[Anaesthesia for Hybrid Procedures]. / Anästhesie für Hybrid-Prozeduren.

The development and implementation of the hybrid operating theatre over the last decade is one of the most innovative advancements in the field of medical interdisciplinary treatment options. The hybrid operating theatre allows the combination of minimally invasive surgery and interventional procedures using the benefits of modern imaging technologies. Therefore, it will be of increasing interest for different kinds of surgical disciplines in the future. In Germany, the hybrid operating theatre is mainly used in the field of transcatheter based heart valve procedures and in the field of vascular surgery cooperating with interventional radiology. Managing this special patient population is a highly challenging task for all players in this setting, especially for the cardiac surgeon, the cardiologist, and the anaesthesiologist. Only close interdisciplinary cooperation ensures optimal treatment. The impact of recent developments in the field of transcatheter based heart valve procedures on anaesthesia management will be addressed in this article.

[Intensive Care in Heart Surgery - is All Now Different?] / Intensivtherapie in der Herzchirurgie ­ alles anders?

With approximately 100000 operations performed in Germany per year, cardiac surgery is among the surgical specialties that require intensive care tratment most frequently. Although all therapeutic aspects of ICU treatment are of high importance among cardiac surgery patients, there is a focus on hemodynamics with the overarching goal of sufficient oxygen delivery. Patients undergoing cardiac surgery are particularily prone to hemodynamic instability and low cardiac output syndrome, potentially culminating into cardiogenic shock. This article presents an overview of essential elements of intensive care medicine in cardiac surgery, paying special attention to hemodynamic monitoring, low cardiac output syndrome, inotropy, cardiac arrhyhmia, perioperative myocardial infarction, and patient blood management.

[Hemodynamic Monitoring 2.0 - What is Possible on Normal Wards?] / Hämodynamisches Monitoring 2.0 ­ was ist auf Normalstation möglich?

Life threatening events after surgery often occur on the ward. These events could be prevented by early detection of clinical deterioration of patients' health status during ward care. Therefore, an adequate monitoring could help to identify patients at risk, since there is an imbalance of monitoring intensity and the occurrence of life-threatening events during hospital stay.Additional monitoring on the general ward could lead to more patient safety. The practicability of additional monitoring needs to be considered, and therefore the use of available monitoring systems on the ward is limited. Capillary refill time (CRT) and the passive leg raise test (PLR) seem to be usable intermittent monitoring techniques.Continuous monitoring systems ensure a better detection of unwanted events and hemodynamic trends. However, the increased workload for the nursing staff and tethered monitors are unfavorable. Future trends of developing wireless monitoring systems are of paramount importance in this respect. Controlling artefacts is crucial for the successful balance between false alarms and "missed events". An adequate reaction is needed when detecting adverse events to avoid a "failure to rescue".

Comparison of adequacy of anaesthesia monitoring with standard clinical practice monitoring during routine general anaesthesia: An international, multicentre, single-blinded randomised controlled trial.

BACKGROUND: Previous studies have suggested that monitoring the levels of both hypnosis and antinociception could reduce periods of inadequate anaesthesia. However, the evidence regarding associated benefits of this monitoring is still limited. OBJECTIVE: The primary objective of this study was to confirm that guidance of anaesthesia by depth of hypnosis and antinociception monitoring decreases the number of inadequate anaesthesia events in comparison with standard clinical practice. DESIGN: A multicentre, single-blinded, randomised controlled trial. SETTING: The study was conducted in four European University hospitals in four different countries between December 2013 and November 2016. PATIENTS: The study population consisted of a total of 494 adult patients undergoing elective surgery requiring tracheal intubation. INTERVENTIONS: The patients were allocated to one of two groups. The first group was treated using Entropy for depth of hypnosis and surgical pleth index to determine depth of antinociception (adequacy of anaesthesia group; AoA group). The second group was monitored using standard monitoring alone (control group). Anaesthesia was conducted with target-controlled infusions of propofol and remifentanil. MAIN OUTCOME MEASURES: The primary outcome of the study was the number of total unwanted events for example signs of inadequately light or unintentionally deep anaesthesia. RESULTS: Evidence of inadequate anaesthesia had an incidence of around 0.7 events per patient in both groups with no difference between groups (P = 0.519). In the AoA group, the overall consumption of propofol was significantly reduced (6.9 vs. 7.5 mg kg h, P = 0.008) in comparison with the control group. The consumption of remifentanil was equal in both groups. The times to emergence [8.0 vs. 9.6 min (P = 0.005)] and full recovery in the postanaesthesia care unit (P = 0.043) were significantly shorter in the AoA group. No differences were seen in postoperative pain scores or in the use of analgesics. CONCLUSION: In the current study, the guidance of total intravenous anaesthesia by Entropy and surgical pleth index in comparison with standard monitoring alone was not able to validate reduction of unwanted anaesthesia events. However, there was a reduction in the use of propofol, and shorter times for emergence and time spent in the postanaesthesia care unit. TRIAL REGISTRATION: at ClinicalTrials.gov NCT01928875.

Genome-wide association study of myocardial infarction, atrial fibrillation, acute stroke, acute kidney injury and delirium after cardiac surgery - a sub-analysis of the RIPHeart-Study.

BACKGROUND: The aim of our study was the identification of genetic variants associated with postoperative complications after cardiac surgery. METHODS: We conducted a prospective, double-blind, multicenter, randomized trial (RIPHeart). We performed a genome-wide association study (GWAS) in 1170 patients of both genders (871 males, 299 females) from the RIPHeart-Study cohort. Patients undergoing non-emergent cardiac surgery were included. Primary endpoint comprises a binary composite complication rate covering atrial fibrillation, delirium, non-fatal myocardial infarction, acute renal failure and/or any new stroke until hospital discharge with a maximum of fourteen days after surgery. RESULTS: A total of 547,644 genotyped markers were available for analysis. Following quality control and adjustment for clinical covariate, one SNP reached genome-wide significance (PHLPP2, rs78064607, p = 3.77 × 10- 8) and 139 (adjusted for all other outcomes) SNPs showed promising association with p < 1 × 10- 5 from the GWAS. CONCLUSIONS: We identified several potential loci, in particular PHLPP2, BBS9, RyR2, DUSP4 and HSPA8, associated with new-onset of atrial fibrillation, delirium, myocardial infarction, acute kidney injury and stroke after cardiac surgery. TRIAL REGISTRATION: The study was registered with ClinicalTrials.gov NCT01067703, prospectively registered on 11 Feb 2010.

[Cardiac Anaesthesia: Anaesthesiological Management]. / Kardioanästhesie: anästhesiologisches Management.

The anaesthesiological management of patients scheduled for cardiac surgery has been refined distinctively over the last decade due to different reasons. The continuing growth of the elderly patient population and the increasing number of combined cardiac surgery procedures in octogenarians on the one hand are one aspect. The rapid development of minimally invasive cardiac surgery and the enhancements in mechanical, artificial heart assist devices on the other hand can be seen as additional decisive factors. All of these innovations in the field of cardiac surgery implicate further enhancements regarding the anaesthesiological management. This review article addresses the following subareas of cardiac anaesthesia: significance of pharmacological myocardial protection, anaesthetic management during cardiopulmonary bypass, importance of "Enhanced Recovery After Cardiac Surgery"-protocols as well as innovations in the field of minimally invasive cardiac surgery like transcatheter aortic valve implantation.

[Coagulation Monitoring and Bleeding Management in Cardiac Surgery]. / Kardioanästhesie: Monitoring der Gerinnung und Gerinnungstherapie.

The transfusion of allogeneic blood products is associated with increased morbidity and mortality. An impaired hemostasis is frequently found in patients undergoing cardiac surgery and may in turn cause bleeding and transfusions. A goal directed coagulation management addressing the often complex coagulation disorders needs sophisticated diagnostics. This may improve both patients' outcome and costs. Recent data suggest that coagulation management based on a rational algorithm is more effective than traditional therapy based on conventional laboratory variables such as PT and INR. Platelet inhibitors, cumarins, direct oral anticoagulants and heparin need different diagnostic and therapeutic approaches. An algorithm specifically developed for use during cardiac surgery is presented.

RIPHeart (Remote Ischemic Preconditioning for Heart Surgery) Study: Myocardial Dysfunction, Postoperative Neurocognitive Dysfunction, and 1 Year Follow-Up.

BACKGROUND: Remote ischemic preconditioning (RIPC) has been suggested to protect against certain forms of organ injury after cardiac surgery. Previously, we reported the main results of RIPHeart (Remote Ischemic Preconditioning for Heart Surgery) Study, a multicenter trial randomizing 1403 cardiac surgery patients receiving either RIPC or sham-RIPC. METHODS AND RESULTS: In this follow-up paper, we present 1-year follow-up of the composite primary end point and its individual components (all-cause mortality, myocardial infarction, stroke and acute renal failure), in a sub-group of patients, intraoperative myocardial dysfunction assessed by transesophageal echocardiography and the incidence of postoperative neurocognitive dysfunction 5 to 7 days and 3 months after surgery. RIPC neither showed any beneficial effect on the 1-year composite primary end point (RIPC versus sham-RIPC 16.4% versus 16.9%) and its individual components (all-cause mortality [3.4% versus 2.5%], myocardial infarction [7.0% versus 9.4%], stroke [2.2% versus 3.1%], acute renal failure [7.0% versus 5.7%]) nor improved intraoperative myocardial dysfunction or incidence of postoperative neurocognitive dysfunction 5 to 7 days (67 [47.5%] versus 71 [53.8%] patients) and 3 months after surgery (17 [27.9%] versus 18 [27.7%] patients), respectively. CONCLUSIONS: Similar to our main study, RIPC had no effect on intraoperative myocardial dysfunction, neurocognitive function and long-term outcome in cardiac surgery patients undergoing propofol anesthesia. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01067703.

Effect of Xenon Anesthesia Compared to Sevoflurane and Total Intravenous Anesthesia for Coronary Artery Bypass Graft Surgery on Postoperative Cardiac Troponin Release: An International, Multicenter, Phase 3, Single-blinded, Randomized Noninferiority Trial.

BACKGROUND: Ischemic myocardial damage accompanying coronary artery bypass graft surgery remains a clinical challenge. We investigated whether xenon anesthesia could limit myocardial damage in coronary artery bypass graft surgery patients, as has been reported for animal ischemia models. METHODS: In 17 university hospitals in France, Germany, Italy, and The Netherlands, low-risk elective, on-pump coronary artery bypass graft surgery patients were randomized to receive xenon, sevoflurane, or propofol-based total intravenous anesthesia for anesthesia maintenance. The primary outcome was the cardiac troponin I concentration in the blood 24 h postsurgery. The noninferiority margin for the mean difference in cardiac troponin I release between the xenon and sevoflurane groups was less than 0.15 ng/ml. Secondary outcomes were the safety and feasibility of xenon anesthesia. RESULTS: The first patient included at each center received xenon anesthesia for practical reasons. For all other patients, anesthesia maintenance was randomized (intention-to-treat: n = 492; per-protocol/without major protocol deviation: n = 446). Median 24-h postoperative cardiac troponin I concentrations (ng/ml [interquartile range]) were 1.14 [0.76 to 2.10] with xenon, 1.30 [0.78 to 2.67] with sevoflurane, and 1.48 [0.94 to 2.78] with total intravenous anesthesia [per-protocol]). The mean difference in cardiac troponin I release between xenon and sevoflurane was -0.09 ng/ml (95% CI, -0.30 to 0.11; per-protocol: P = 0.02). Postoperative cardiac troponin I release was significantly less with xenon than with total intravenous anesthesia (intention-to-treat: P = 0.05; per-protocol: P = 0.02). Perioperative variables and postoperative outcomes were comparable across all groups, with no safety concerns. CONCLUSIONS: In postoperative cardiac troponin I release, xenon was noninferior to sevoflurane in low-risk, on-pump coronary artery bypass graft surgery patients. Only with xenon was cardiac troponin I release less than with total intravenous anesthesia. Xenon anesthesia appeared safe and feasible.

Prevalence, Diagnosis, Perioperative Monitoring and Treatment of Right Ventricular Dysfunction and/or Pulmonary Arterial Hypertension in Cardiac Surgical Patients in Germany-A Postal Survey.

Background Sparse data are available on the prevalence of right ventricular dysfunction and/or pulmonary arterial hypertension in patients scheduled for cardiac surgery in Germany as well as on the intensity and modalities used for diagnosis, perioperative monitoring, and treatment of these comorbidities. Methods A postal survey including questions on the prevalence of preoperative right ventricular dysfunction and/or pulmonary arterial hypertension in patients undergoing cardiac surgery in 2009 was sent to 81 German heart centers. Total 47 of 81 (58%) heart centers returned the questionnaires. The centers reported data on 51,095 patients, and 49.8% of the procedures were isolated coronary artery bypass grafting. Results Data on the prevalence of preoperative pulmonary hypertension and/or right ventricular dysfunction were not available in 54% and 64.6% of centers. In the remaining hospitals, 19.5% of patients presented right heart dysfunction and 10% pulmonary arterial hypertension. Preoperative echocardiography was performed in only 45.3% of the coronary artery bypass grafting cases. Preoperative pharmacologic treatment of pulmonary hypertension or right ventricular dysfunction with oral sildenafil, inhaled prostanoids, or nitric oxide was initiated in 71% and 95.7% of the centers, respectively. Intra- and postoperative treatment was most frequently accomplished with phosphodiesterase-III inhibitors. Conclusion The prevalence of preoperative right heart dysfunction and pulmonary arterial hypertension in cardiac surgical patients in Germany seems to be substantial. However, in more than 50% of the patients, no preoperative data on right ventricular function and pulmonary arterial pressure are available. This may lead to underestimation of perioperative risk and inappropriate management of this high-risk population.

Non-invasive hemodynamic optimization in major abdominal surgery: a feasibility study.

BACKGROUND: Today, most of the pre-emptive hemodynamic optimization algorithms are based on variables associated with invasive techniques like arterial cannulation. The non-invasive Nexfin™ technology is able to estimate continuous Cardiac Index (CI) and pulse pressure variation (PPV). However, the efficiency of an early goal directed therapy (EGDT) algorithm based on non-invasive variables has to be proven. The aim of our study was to investigate the feasibility of a non-invasive driven EGDT protocol and its impact on patient's outcome. METHODS: Seventy-nine patients (ASA II-III) undergoing elective major abdominal surgery were randomized to either study group (SG, N.=39) or control group (CG, N.=40). The SG was treated according to an algorithm based on non-invasive CI and PPV, whereas the CG received standard of care. Postoperative complications up to 28 days and length of hospital stay (LOS) in both groups were recorded. RESULTS: There was no significant difference between the groups regarding demographics, hemodynamic variables, preoperative risk scores and duration of surgery. The total amount of complications was higher in the CG (SG 94 vs. CG 132 complications, P=0.22) without reaching statistical significance. LOS revealed no difference between both groups (SG, 9 [7-15] vs. CG, 9 [7-15.25] days, P=0.82). We have seen no impact of the non-invasive optimization protocol with respect to postoperative mortality. CONCLUSIONS: In this patient collective, we could demonstrate the feasibility of a non-invasive approach for hemodynamic optimization. However, EGDT based on non-invasive variables was not able to significantly improve outcome.

Warming before and after epidural block before general anaesthesia for major abdominal surgery prevents perioperative hypothermia: A randomised controlled trial.

BACKGROUND: Epidural analgesia (EDA) is known to be an independent risk factor for perioperative hypothermia and its many known adverse effects. Combined general and epidural anaesthesia decreases intraoperative core temperature more rapidly than general anaesthesia alone. Hence, adequate warming procedures are needed for these patients. OBJECTIVE: We evaluated the effects of active skin-surface warming before and/or after initiation of EDA during general anaesthesia as a procedure to prevent perioperative hypothermia. DESIGN: A randomised controlled trial. SETTING: Department of Anaesthesiology in a general hospital in Germany from January 2013 until August 2014. PATIENTS: After obtaining written informed consent, we included 99 adult patients undergoing elective major abdominal surgery under combined general anaesthesia and EDA with an expected duration of surgery of at least 120 min. Patients were excluded if they were under 18 years of age, classified as American Society of Anesthesiologists' physical status 4 or higher or if patients refused EDA. INTERVENTIONS: Patients were randomly assigned to one of three groups and received either only passive insulation, 15 min of active air-forced warming after EDA and before induction of general anaesthesia, or two periods, each of 15 min, of active air-forced warming before and after EDA. Core and skin temperatures were measured at several time points throughout the study. MAIN OUTCOME MEASURES: The primary outcome measure was the incidence of hypothermia on arrival in the ICU. The secondary outcome measure was the incidence of postoperative shivering. In addition, the perioperative change in body core temperature was recorded. RESULTS: Without prewarming (n = 32), 72% of patients became hypothermic (<36°C) at the end of anaesthesia. Fifteen minutes of warming after insertion of the epidural catheter and before initiation of general anaesthesia reduced the incidence of postoperative hypothermia to 6% (n = 33). After two periods of 15 min of warming before and after insertion of the epidural catheter, no patient became hypothermic (n = 34). Prewarming in either 'warming' group prevents the initial temperature drop which was observed in the control group. CONCLUSION: Warming for 15 min before and after initiation of EDA in patients receiving combined anaesthesia is effective in preventing postoperative hypothermia. TRIAL REGISTRATION: This trial was registered with ClinicalTrials.gov (identifier: NCT01795482).

Accuracy of Cardiac Output by Nine Different Pulse Contour Algorithms in Cardiac Surgery Patients: A Comparison with Transpulmonary Thermodilution.

Objective. Today, there exist several different pulse contour algorithms for calculation of cardiac output (CO). The aim of the present study was to compare the accuracy of nine different pulse contour algorithms with transpulmonary thermodilution before and after cardiopulmonary bypass (CPB). Methods. Thirty patients scheduled for elective coronary surgery were studied before and after CPB. A passive leg raising maneuver was also performed. Measurements included CO obtained by transpulmonary thermodilution (COTPTD) and by nine pulse contour algorithms (COX1-9). Calibration of pulse contour algorithms was performed by esophageal Doppler ultrasound after induction of anesthesia and 15 min after CPB. Correlations, Bland-Altman analysis, four-quadrant, and polar analysis were also calculated. Results. There was only a poor correlation between COTPTD and COX1-9 during passive leg raising and in the period before and after CPB. Percentage error exceeded the required 30% limit. Four-quadrant and polar analysis revealed poor trending ability for most algorithms before and after CPB. The Liljestrand-Zander algorithm revealed the best reliability. Conclusions. Estimation of CO by nine different pulse contour algorithms revealed poor accuracy compared with transpulmonary thermodilution. Furthermore, the less-invasive algorithms showed an insufficient capability for trending hemodynamic changes before and after CPB. The Liljestrand-Zander algorithm demonstrated the highest reliability. This trial is registered with NCT02438228 (ClinicalTrials.gov).

[Transcatheter aortic valve implantation ­ What does the anaesthetist need to know and pay attention to?]. / Transkatheter-Aortenklappenimplantation ­ Was muss der Anästhesist wissen und beachten?

Recent advancements in the field of cardiovascular surgery have been dominated by 3 aspects that comparably challenge a sophisticated cardiological, surgical and anaesthesiological management of this patient population. The proportion of elderly patients with relevant comorbidities increases steadily, and the number of combined cardiac surgical procedures is rising in this elderly population. A very important innovation in the last decade pertaining to the treatment of elderly patients at high risk suffering from significant aortic stenosis is the minimally invasive transcatheter aortic valve implantation (TAVI). Over the last 7 years this interventional-surgical "hybrid-procedure" has increased in numbers from almost 0 to 10,500 procedures in 2013 in Germany, performed at more than 80 centers. These patients relevant comorbidities accounting for a high risk of perioperative complications and moreover for a high mortality. The combination of a patient at high risk with the specific characteristics of the TAVI procedure necessitates to update the required skills of anaesthetists responsible for providing care for this kind of procedure.

Accuracy of an autocalibrated pulse contour analysis in cardiac surgery patients: a bi-center clinical trial.

BACKGROUND: Less-invasive and easy to install monitoring systems for continuous estimation of cardiac index (CI) have gained increasing interest, especially in cardiac surgery patients who often exhibit abrupt haemodynamic changes. The aim of the present study was to compare the accuracy of CI by a new semi-invasive monitoring system with transpulmonary thermodilution before and after cardiopulmonary bypass (CPB). METHODS: Sixty-five patients (41 Germany, 24 Spain) scheduled for elective coronary surgery were studied before and after CPB, respectively. Measurements included CI obtained by transpulmonary thermodilution (CITPTD) and autocalibrated semi-invasive pulse contour analysis (CIPFX). Percentage changes of CI were also calculated. RESULTS: There was only a poor correlation between CITPTD and CIPFX both before (r (2) = 0.34, p < 0.0001) and after (r (2) = 0.31, p < 0.0001) CPB, with a percentage error (PE) of 62 and 49 %, respectively. Four quadrant plots revealed a concordance rate over 90 % indicating an acceptable correlation of trends between CITPTD and CIPFX before (concordance: 93 %) and after (concordance: 94 %) CPB. In contrast, polar plot analysis showed poor trending before and an acceptable trending ability of changes in CI after CPB. CONCLUSIONS: Semi-invasive CI by autocalibrated pulse contour analysis showed a poor ability to estimate CI compared with transpulmonary thermodilution. Furthermore, the new semi-invasive device revealed an acceptable trending ability for haemodynamic changes only after CPB. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02312505 Date: 12.03.2012.

A Multicenter Trial of Remote Ischemic Preconditioning for Heart Surgery.

BACKGROUND: Remote ischemic preconditioning (RIPC) is reported to reduce biomarkers of ischemic and reperfusion injury in patients undergoing cardiac surgery, but uncertainty about clinical outcomes remains. METHODS: We conducted a prospective, double-blind, multicenter, randomized, controlled trial involving adults who were scheduled for elective cardiac surgery requiring cardiopulmonary bypass under total anesthesia with intravenous propofol. The trial compared upper-limb RIPC with a sham intervention. The primary end point was a composite of death, myocardial infarction, stroke, or acute renal failure up to the time of hospital discharge. Secondary end points included the occurrence of any individual component of the primary end point by day 90. RESULTS: A total of 1403 patients underwent randomization. The full analysis set comprised 1385 patients (692 in the RIPC group and 693 in the sham-RIPC group). There was no significant between-group difference in the rate of the composite primary end point (99 patients [14.3%] in the RIPC group and 101 [14.6%] in the sham-RIPC group, P=0.89) or of any of the individual components: death (9 patients [1.3%] and 4 [0.6%], respectively; P=0.21), myocardial infarction (47 [6.8%] and 63 [9.1%], P=0.12), stroke (14 [2.0%] and 15 [2.2%], P=0.79), and acute renal failure (42 [6.1%] and 35 [5.1%], P=0.45). The results were similar in the per-protocol analysis. No treatment effect was found in any subgroup analysis. No significant differences between the RIPC group and the sham-RIPC group were seen in the level of troponin release, the duration of mechanical ventilation, the length of stay in the intensive care unit or the hospital, new onset of atrial fibrillation, and the incidence of postoperative delirium. No RIPC-related adverse events were observed. CONCLUSIONS: Upper-limb RIPC performed while patients were under propofol-induced anesthesia did not show a relevant benefit among patients undergoing elective cardiac surgery. (Funded by the German Research Foundation; RIPHeart ClinicalTrials.gov number, NCT01067703.).

[Can anaesthetic management improve the outcome?]. / Patientensicherheit in der Anästhesie - Kann der Anästhesist das Outcome verbessern?

Despite anaesthesia-specific pharmacological and technological innovations in the last decades we are definitely aware that anaesthesia per se has the potential to induce changes in the balance of human physiology that in turn may have relevant consequences, i.e. an increase in postoperative morbidity and mortality. Today anaesthesia appears to be extremely safe, with the number of deaths solely attributed to anaesthesia having reached its lowest point in history (0.055 per 10 000 anaesthetics). However, the available data regarding anaesthesia-related mortality, solely or contributory, are not consistent and the interpretation and legibility is limited. Fortunately, the issue of "patient safety in anaesthesiology" has gained increasing interest in the last few years, yielding some very promising projects. Since most of the ideas are focused on intraoperative safety improvement strategies, it seems to be reasonable in the near future to expand to the complete perioperative period, especially the postoperative care on the ward in high-risk patients. This knowledge, combined with an ongoing promotion of patient safety in anaesthesiology and provision of adequate resources definitely will increase patient safety. Hopefully, in the end, our efforts will contribute to integrate the "patient safety in anaesthesiology concept" in daily clinical routine.

Preventing inadvertent perioperative hypothermia.

BACKGROUND: 25-90% of all patients undergoing elective surgery suffer from inadvertent postoperative hypothermia, i.e., a core body temperature below 36°C. Compared to normothermic patients, these patients have more frequent wound infections (relative risk [RR] 3.25, 95% confidence interval [CI] 1.35-7.84), cardiac complications (RR 4.49, 95% CI 1.00-20.16), and blood transfusions (RR 1.33, 95% CI 1.06-1.66). Hypothermic patients feel uncomfortable, and shivering raises oxygen consumption by about 40%. METHODS: This guideline is based on a systematic review of the literature up to and including October 2012 and a further one from November 2012 to August 2014. The recommendations were developed and agreed upon by representatives of five medical specialty societies in a structured consensus process. RESULTS: The patient's core temperature should be measured 1-2 hours before the start of anesthesia, and either continuously or every 15 minutes during surgery. Depending on the nature of the operation, the site of temperature measurement should be oral, naso-/oropharyngeal, esophageal, vesical, or tympanic (direct). The patient should be actively prewarmed 20-30 minutes before surgery to counteract the decline in temperature. Prewarmed patients must be actively warmed intraoperatively as well if the planned duration of anesthesia is longer than 60 minutes (without prewarming, 30 minutes). The ambient temperature in the operating room should be at least 21°C for adult patients and at least 24°C for children. Infusions and blood transfusions that are given at rates of >500 mL/h should be warmed first. Perioperatively, the largest possible area of the body surface should be thermally insulated. Emergence from general anesthesia should take place at normal body temperature. Postoperative hypothermia, if present, should be treated by the administration of convective or conductive heat until normothermia is achieved. Shivering can be treated with medications. CONCLUSION: Inadvertent perioperative hypothermia can adversely affect the outcome of surgery and the patient's postoperative course. It should be actively prevented.