Does preoperative multidisciplinary team assessment of high-risk patients improve the safety and outcomes of patients undergoing surgery?

BACKGROUND: International guidelines recommend preoperative multidisciplinary team (MDT) assessment for high-risk surgical patients. Preoperative MDT meetings can help to improve surgical care, but there is little evidence on whether they improve patient outcomes. METHODS: This paper aims to share our experience of MDT meetings for high-risk surgical patients to underline their added value to the current standard of care. An observational study of a retrospective cohort of preoperative high-risk MDT meetings of a tertiary referral hospital between January 2015 and December 2020. For 249 patients the outcomes preoperative data, MDT decisions, and patient outcomes were collected from electronic health records. MAIN RESULTS: A total of 249 patients were discussed at high-risk MDT meetings. Most of the patients (97%) were assessed as having an American Society of Anesthesiology score ≥ 3, and 219 (88%) had a European Society of Cardiology and European Society of Anaesthesiology risk score of intermediate or high. After MDT assessment, 154 (62%) were directly approved for surgery, and 39 (16%) were considered ineligible for surgery. The remaining 56 (23%) patients underwent additional assessments before reconsideration at a high-risk MDT meeting. The main reason for patients being discussed at the high-risk MDT meeting was to assess the risk-benefit ratio of surgery. Ultimately, 184 (74%) patients underwent surgery. Of the operated patients, 122 (66%) did not have a major complication in the postoperative period, and 149 patients (81%) were alive after one year. CONCLUSIONS: This cohort study shows the vulnerability and complexity of high-risk patients but also shows that the use of an MDT assessment contributes too improved peri- and postoperative treatment strategies in high-risk patients. Most patients underwent surgery after careful risk assessment and, if deemed necessary, preoperative and perioperative treatment optimization to reduce their risk.

Breathing variability during propofol/remifentanil procedural sedation with a single additional dose of midazolam or s-ketamine: a prospective observational study.

PURPOSE: Regulation of spontaneous breathing is highly complex and may be influenced by drugs administered during the perioperative period. Because of their different pharmacological properties we hypothesized that midazolam and s-ketamine exert different effects on the variability of minute ventilation (MV), tidal volume (TV) and respiratory rate (RR). METHODS: Patients undergoing procedural sedation (PSA) with propofol and remifentanil received a single dose of midazolam (1-3 mg, n = 10) or s-ketamine (10-25 mg, n = 10). We used non-invasive impedance-based respiratory volume monitoring to record RR as well as changes in TV and MV. Variability of these three parameters was calculated as coefficients of variation. RESULTS: TV and MV decreased during PSA to a comparable extent in both groups, whereas there was no significant change in RR. In line with our hypothesis we observed marked differences in breathing variability. The variability of MV (- 47.5% ± 24.8%, p = 0.011), TV (- 42.1% ± 30.2%, p = 0.003), and RR (- 28.5% ± 29.3%, p = 0.011) was significantly reduced in patients receiving midazolam. In contrast, variability remained unchanged in patients receiving s-ketamine (MV + 16% ± 45.2%, p = 0.182; TV +12% ± 47.7%, p = 0.390; RR +39% ± 65.2%, p = 0.129). After termination of PSA breathing variables returned to baseline values. CONCLUSIONS: While midazolam reduces respiratory variability in spontaneously breathing patients undergoing procedural sedation, s-ketamine preserves variability suggesting different effects on the regulation of spontaneous breathing.

Frailty as a growing challenge for anesthesiologists - results of a Dutch national survey.

BACKGROUND: Frailty is a multidimensional condition characterized by loss of functional reserve, which results in increased vulnerability to adverse outcomes following surgery. Anesthesiologists can reduce adverse outcomes when risk factors are recognized early and dedicated care pathways are operational. As the frail elderly population is growing, we investigated the perspective on the aging population, familiarity with the frailty syndrome and current organization of perioperative care for elderly patients among Dutch anesthesiologists. METHODS: A fifteen-item survey was distributed among anesthesiologists and residents during the annual meeting of the Dutch Society of Anesthesiology. The first section included questions on self-reported competence on identification of frailty, acquaintance with local protocols and attitude towards the increasing amounts of elderly patients presenting for surgery. The second part included questions on demographic features of the participant such as job position, experience and type of hospital. Answers are presented as percentages, using the total number of replies for the question per group as a denominator. RESULTS: A sample of 132 surveys was obtained. The increasing number of elderly patients was primarily perceived as challenging by 76% of respondents. Ninety-nine percent agreed that frailty should influence anesthetic management, while 85% of respondents claimed to feel competent to recognize frailty. Thirty-four percent of respondents reported the use of a dedicated pathway in the preoperative approach of frail elderly patients. However, only 30% of respondents reported to know where to find the frailty screening in the patient file and appointed that frailty is not consistently documented. Interestingly, only 43% of respondents reported adequate collaboration with geriatricians. This could include for example a standardized preoperative multidisciplinary approach or dedicated pathway for the elderly patient. CONCLUSIONS: This survey demonstrated that the increasing number of frail elderly patients is perceived as important and relevant for anesthetic management. Opportunities lie in improving the organization and effectuation of perioperative care by more consistent involvement of anesthesiologists.

Between-trial heterogeneity in ARDS research.

PURPOSE: Most randomized controlled trials (RCTs) in patients with acute respiratory distress syndrome (ARDS) revealed indeterminate or conflicting study results. We aimed to systematically evaluate between-trial heterogeneity in reporting standards and trial outcome. METHODS: A systematic review of RCTs published between 2000 and 2019 was performed including adult ARDS patients receiving lung-protective ventilation. A random-effects meta-regression model was applied to quantify heterogeneity (non-random variability) and to evaluate trial and patient characteristics as sources of heterogeneity. RESULTS: In total, 67 RCTs were included. The 28-day control-group mortality rate ranged from 10 to 67% with large non-random heterogeneity (I2 = 88%, p < 0.0001). Reported baseline patient characteristics explained some of the outcome heterogeneity, but only six trials (9%) reported all four independently predictive variables (mean age, mean lung injury score, mean plateau pressure and mean arterial pH). The 28-day control group mortality adjusted for patient characteristics (i.e. the residual heterogeneity) ranged from 18 to 45%. Trials with significant benefit in the primary outcome reported a higher control group mortality than trials with an indeterminate outcome or harm (mean 28-day control group mortality: 44% vs. 28%; p = 0.001). CONCLUSION: Among ARDS RCTs in the lung-protective ventilation era, there was large variability in the description of baseline characteristics and significant unexplainable heterogeneity in 28-day control group mortality. These findings signify problems with the generalizability of ARDS research and underline the urgent need for standardized reporting of trial and baseline characteristics.

Variations in respiratory rate do not reflect changes in tidal volume or minute ventilation after major abdominal surgery.

Monitoring of postoperative pulmonary function usually includes respiratory rate and oxygen saturation measurements. We hypothesized that changes in postoperative respiratory rate do not correlate with changes in tidal volume or minute ventilation. In addition, we hypothesized that variability of minute ventilation and tidal volume is larger than variability of respiratory rate. Respiratory rate and changes in tidal volume and in minute ventilation were continuously measured in 27 patients during 24 h following elective abdominal surgery, using an impedance-based non-invasive respiratory volume monitor (ExSpiron, Respiratory Motion, Waltham, MA, US). Coefficients of variation were used as a measure for variability of respiratory rate, tidal volume and minute ventilation. Data of 38,149 measurements were analyzed. We found no correlation between respiratory rate and tidal volume or minute ventilation (r2 = 0.02 and 0.01). Mean respiratory rate increased within the first 24 h after abdominal surgery from 13.9 ± 2.5 to 16.2 ± 2.4 breaths/min (p = 0.008), while tidal volume and minute ventilation remained unchanged (p = 0.90 and p = 0.18). Of interest, variability of respiratory rate (0.21 ± 0.06) was significantly smaller than variability of tidal volume (0.37 ± 0.12, p < 0.001) and minute ventilation (0.41 ± 0.12, p < 0.001). Changes in postoperative respiratory rate do not allow conclusions about changes in tidal volume or minute ventilation. We suggest that postoperative alveolar hypoventilation may not be recognized by monitoring respiratory rate alone. Variability of respiratory rate is smaller than variability in tidal volume and minute ventilation, suggesting that adaptations of alveolar ventilation to metabolic needs may be predominately achieved by variations in tidal volume.

Prehospital fluid administration in patients with severe traumatic brain injury: A systematic review and meta-analysis.

BACKGROUND: Prehospital management of severe traumatic brain injury (TBI) focuses on preventing secondary brain injury. Therefore, hypotension should be prevented, or if present, should be promptly treated in order to maintain optimal cerebral perfusion pressure. Fluid resuscitation is a traditional mainstay in the prehospital treatment of hypotension, however, the choice of fluid type that is to be administered in the prehospital setting is the subject of an on-going debate. This systematic review and meta-analysis was therefore performed to assess the effect of different fluid types on outcome in patients with severe TBI. METHODS: PubMed, Embase and Web of Science were searched for articles up to March 2020. Studies comparing two or more prehospital administered fluid types with suspected or confirmed severe TBI were deemed eligible for inclusion. Studied outcomes were mortality and (extended) Glasgow Outcome Scale (GOS). The meta-analysis tested for differences in survival between hypertonic saline (HTS) and normotonic crystalloids (i.e. normal saline or Lactated Ringer's) and between hypertonic saline with dextran (HSD) and normotonic crystalloids. The systematic review is registered in the PROSPERO register with number CRD42020140423. RESULTS: This literature search yielded a total of 519 articles, of which 12 were included in the systematic review and 6 were included in the meta-analysis. Eleven studies found no statistically significant difference in survival between patients treated with different fluid types (e.g. normal saline and hypertonic saline). All studies assessing neurological outcome, measured through (extended) GOS, found no statistically significant difference between different fluid types. Meta-analysis showed no better survival for patients treated with HSD, when compared to normotonic crystalloids (overall RR 0.99, 95% CI 0.93-1.06). Moreover, HTS compared to normotonic crystalloids does not result in a better survival (overall RR 1.04, 95% CI 0.97-1.12). CONCLUSIONS: This systematic review and meta-analysis did not demonstrate a survival or neurological benefit for one specific fluid type administered in the prehospital setting.

Discrepancy between the initial assessment of injury severity and post hoc determination of injury severity in patients with apparently mild traumatic brain injury: a retrospective multicenter cohort analysis.

PURPOSE: Traumatic brain injury (TBI) is a major cause of trauma-related visits to emergency departments (ED). Determination of monitoring requirements of patients with apparently mild TBI is challenging. Patients may turn out to be more severely injured than initially assumed, and failure to identify these patients constitutes a serious threat to patient safety. We, therefore, aimed to identify clinical risk factors for more severe injuries in patients with apparently mild TBI. METHODS: In a retrospective cohort analysis performed at two level I trauma centers, 808 patients aged ≥ 16 presenting to the ED with head trauma and a Glasgow Coma Scale (GCS) score 13-15 who received a head CT scan were studied. Discrepancies between the initial TBI severity as determined by GCS and severity as determined post hoc by the Head Abbreviated Injury Score were assessed. Multiple logistic regression was used to identify risk factors of such discrepancies. RESULTS: 104 (12.9%) patients were more severely injured than initially classified. A GCS < 15 at presentation (GCS 13: OR 6.2, [95% CI 3.8-9.9]; GCS 14: OR 2.7, [2.0-3.7]), an SpO2 < 90% (OR 5.4, [1.2-23.4]), loss of consciousness (OR 2.3, [1.5-3.5]), absence of equal and reactive pupils (OR 2.1, [1.6-2.7]), transport by ambulance (OR 2.0, [1.7-2.4]), and use of anticoagulant drugs (OR 1.2, [1.1-1.3]) were independent risk factors of more severe injury. CONCLUSIONS: Six risk factors of more severe injury in patients presenting with apparently mild TBI were identified. Patients with any of these factors should be thoroughly monitored for signs of neurologic deterioration.

The added value of cardiac index and pulse pressure variation monitoring to mean arterial pressure-guided volume therapy in moderate-risk abdominal surgery (COGUIDE): a pragmatic multicentre randomised controlled trial.

There is disagreement regarding the benefits of goal-directed therapy in moderate-risk abdominal surgery. Therefore, we tested the hypothesis that the addition of non-invasive cardiac index and pulse pressure variation monitoring to mean arterial pressure-based goal-directed therapy would reduce the incidence of postoperative complications in patients having moderate-risk abdominal surgery. In this pragmatic multicentre randomised controlled trial, we randomly allocated 244 patients by envelope drawing in a 1:1 fashion, stratified per centre. All patients had mean arterial pressure, cardiac index and pulse pressure variation measured continuously. In one group, healthcare professionals were blinded to cardiac index and pulse pressure variation values and were asked to guide haemodynamic therapy only based on mean arterial pressure (control group). In the second group, cardiac index and pulse pressure variation values were displayed and kept within target ranges following a pre-defined algorithm (CI-PPV group). The primary endpoint was the incidence of postoperative complications within 30 days. One hundred and seventy-five patients were eligible for final analysis. Overall complication rates were similar (42/94 (44.7%) vs. 38/81 (46.9%) in the control and CI-PPV groups, respectively; p = 0.95). The CI-PPV group had lower mean (SD) pulse pressure variation values (9.5 (2.0)% vs. 11.9 (4.6)%; p = 0.003) and higher mean (SD) cardiac indices (2.76 (0.62) l min-1 .m-2 vs. 2.53 (0.66) l min-1 .m-2 ; p = 0.004) than the control group. In moderate-risk abdominal surgery, we observed no additional value of cardiac index and pulse pressure variation-guided haemodynamic therapy to mean arterial pressure-guided volume therapy with regard to postoperative complications.

Validation of a point-of-care prothrombin time test after cardiopulmonary bypass in cardiac surgery.

Point-of-care coagulation monitoring can be used for the guidance of haemostasis management. However, the influence of time on point-of-care prothrombin time testing following protamine administration after cardiopulmonary bypass has not been investigated. Bland-Altman and error grid analysis were used to analyse the level of agreement between prothrombin time measurements from point-of-care and laboratory tests before cardiopulmonary bypass, and then 3 min, 6 min and 10 min after protamine administration. Prothrombin times were expressed as International Normalised Ratios. While the point-of-care and laboratory prothrombin time measurements showed a high level of agreement before bypass, this agreement deteriorated following protamine administration to a mean (SD) bias of -0.22 (0.13) [limits of agreement 0.48-0.04]. Error grid analysis revealed that 35 (70%) of the paired values showed a clinically relevant discrepancy in international normalised ratio. At 3 min, 6 min and 10 min after cardiopulmonary bypass there is a clinical unacceptable discrepancy between the point-of-care and laboratory measurement of prothrombin time.

Do intravascular hypo- and hypervolaemia result in changes in central blood volumes?

BACKGROUND: Hypovolaemia is generally believed to induce centralization of blood volume. Therefore, we evaluated whether induced hypo- and hypervolaemia result in changes in central blood volumes (pulmonary blood volume (PBV), intrathoracic blood volume (ITBV)) and we explored the effects on the distribution between these central blood volumes and circulating blood volume (Vd circ). METHODS: Six anaesthetized, spontaneously breathing Foxhound dogs underwent random blood volume alterations in steps of 150 ml (mild) to 450 ml (moderate), either by haemorrhage, retransfusion of blood, or colloid infusion. PBV, ITBV and Vd circ were measured using (transpulmonary) dye dilution. The PBV/Vd circ ratio and the ITBV/Vd circ ratio were used as an assessment of blood volume distribution. RESULTS: 68 blood volume alterations resulted in changes in Vdcirc ranging from -33 to +31%. PBV and ITBV decreased during mild and moderate haemorrhage, while during retransfusion, PBV and ITBV increased during moderate hypervolaemia only. The PBV/Vd circ ratio remained constant during all stages of hypo- and hypervolaemia (mean values between 0.20-0.22). This was also true for the ITBV/Vd circ ratio, which remained between 0.31 and 0.32, except for moderate hypervolaemia, where it increased slightly to 0.33 (0.02), P<0.05. CONCLUSIONS: Mild to moderate blood volume alterations result in changes of Vd circ, PBV and ITBV. The ratio between the central blood volumes and Vd circ generally remained unaltered. Therefore, it could be suggested that in anaesthetized spontaneously breathing dogs, the cardiovascular system maintains the distribution of blood between central and circulating blood volume.

Does individual experience affect performance during cardiopulmonary resuscitation with additional external distractors?

Cardiopulmonary resuscitation is perceived as a stressful task. Additional external distractors, such as noise and bystanders, may interfere with crucial tasks and might adversely influence patient outcome. We investigated the effects of external distractors on resuscitation performance of anaesthesia residents and consultants with different levels of experience. Thirty physicians performed two simulated resuscitation scenarios in random order, one scenario without additional distractors (control) and one scenario with additional distractors (noise, scripted family member). Resuscitation performance was assessed by a score based on European Resuscitation Council guidelines, presented as median (IQR [range]). We found that performance scores were lower under experimental conditions (11.8 (9.0-19.5 [-9.0 to 28.5]) than under control conditions 19.5 (14.0-25.5 [5.0-29.5]), p = 0.0002). No interaction was observed between additional distractors and experience level (p = 0.4480). External distractors markedly reduce the quality of cardiopulmonary resuscitation. This suggests that all team members, including senior healthcare providers, require training to improve performance under stressful conditions.

The effect of audible alarms on anaesthesiologists' response times to adverse events in a simulated anaesthesia environment: a randomised trial.

Alarms are ubiquitous in anaesthetic practice, but their net effect on anaesthesiologists' performance and patient safety is debated. In this study, 27 anaesthesiologists performed two simulation sessions in random order; one session was programmed to include an alarm condition, with a standard, frequent, clearly audible alarm sound. During these sessions, adverse events were simulated and anaesthesiologists' response times to these events were recorded. Perceived workload was assessed with the NASA Task Load Index. Response times to adverse events and perceived workload were similar in both groups. Pooled response times to atrial fibrillation and desaturation were fast, with a median (range [IQR]) of 8 (4-14 [1-41]) s and 9 (6-16 [1-44]) s, respectively. Pooled response times to an ST segment elevation on the ECG and an obstructed intravenous line were significantly slower, with median (IQR[range]) times of 34 (21-76[4-300]) s and 227 (95-399 [2-600]) s, respectively (p < 0.001). This study shows that in a simulated anaesthesia environment, response times to adverse events are similar in the absence or presence of an audible alarm, and that response times to various critical events differ.

Application of current guidelines for chest compression depth on different surfaces and using feedback devices: a randomized cross-over study.

BACKGROUND: Current cardiopulmonary resuscitation (CPR)-guidelines recommend an increased chest compression depth and rate compared to previous guidelines, and the use of automatic feedback devices is encouraged. However, it is unclear whether this compression depth can be maintained at an increased frequency. Moreover, the underlying surface may influence accuracy of feedback devices. We investigated compression depths over time and evaluated the accuracy of a feedback device on different surfaces. METHODS: Twenty-four volunteers performed four two-minute blocks of CPR targeting at current guideline recommendations on different surfaces (floor, mattress, 2 backboards) on a patient simulator. Participants rested for 2 minutes between blocks. Influences of time and different surfaces on chest compression depth (ANOVA, mean [95% CI]) and accuracy of a feedback device to determine compression depth (Bland-Altman) were assessed. RESULTS: Mean compression depth did not reach recommended depth and decreased over time during all blocks (first block: from 42 mm [39-46 mm] to 39 mm [37-42 mm]). A two-minute resting period was insufficient to restore compression depth to baseline. No differences in compression depth were observed on different surfaces. The feedback device slightly underestimated compression depth on the floor (bias -3.9 mm), but markedly overestimated on the mattress (bias +12.6 mm). This overestimation was eliminated after correcting compression depth by a second sensor between manikin and mattress. CONCLUSION: Strategies are needed to improve chest compression depth, and more than two providers should alternate with chest compressions. The underlying surface does not necessarily adversely affect CPR performance but influences accuracy of feedback devices. Accuracy is improved by a second, posterior, sensor.

Intra-operative monitoring--many alarms with minor impact.

Alarms are key components of peri-operative monitoring devices, but a high false-alarm rate may lead to desensitisation and neglect. The objective of this study was to quantify the number of alarms and assess the value of these alarms during moderate-risk surgery. For this purpose, we analysed documentation of anaesthesia workstations during 38 surgical procedures. Alarms were classified on technical validity and clinical relevance. The median (IQR [range]) alarm density per procedure was 20.8 (14.5-34.2 [3.7-85.6]) alarms.h⁻¹ (1 alarm every 2.9 min) and increased during induction and emergence of anaesthesia, with up to one alarm per 0.99 min during these periods (p < 0.001). Sixty-four per cent of all alarms were clinically irrelevant, whereas 5% of all alarms required immediate intervention. The positive predictive value of an alarm during induction and emergence was 20% (95% CI 16-24%) and 11% (95% CI 8-14%), respectively. This study shows that peri-operative alarms are frequently irrelevant, with a low predictive value for an emerging event requiring clinical intervention.

Paresis of cranial nerve VI (N. abducens) after thoracic dural perforation.

Epidural anesthesia is associated with the risk of unintended dural perforation and concomitant leakage of cerebrospinal fluid (CSF) from the subarachnoidal space. This may remain asymptomatic or trigger post-dural puncture headache (PDPH). Cerebral nerve lesions after attempted epidural anesthesia are very rare. Here we report a case of unilateral paresis of the cranial nerve VI (N. abducens) after attempted thoracic epidural anesthesia. Herein, diagnosis of N. abducens paresis was probably delayed because the optical symptoms, such as blurred and double vision, were attributed to optical hallucinations caused by a concomitant (S)-ketamine infusion. In all patients with optical symptoms such as blurred or double vision a paresis of the abducens nerve should be considered.