Tracheal intubation in critically ill adults with a physiologically difficult airway. An international Delphi study.

PURPOSE: Our study aimed to provide consensus and expert clinical practice statements related to airway management in critically ill adults with a physiologically difficult airway (PDA). METHODS: An international Steering Committee involving seven intensivists and one Delphi methodology expert was convened by the Society of Critical Care Anaesthesiologists (SOCCA) Physiologically Difficult Airway Task Force. The committee selected an international panel of 35 expert clinician-researchers with expertise in airway management in critically ill adults. A Delphi process based on an iterative approach was used to obtain the final consensus statements. RESULTS: The Delphi process included seven survey rounds. A stable consensus was achieved for 53 (87%) out of 61 statements. The experts agreed that in addition to pathophysiological conditions, physiological alterations associated with pregnancy and obesity also constitute a physiologically difficult airway. They suggested having an intubation team consisting of at least three healthcare providers including two airway operators, implementing an appropriately designed checklist, and optimizing hemodynamics prior to tracheal intubation. Similarly, the experts agreed on the head elevated laryngoscopic position, routine use of videolaryngoscopy during the first attempt, preoxygenation with non-invasive ventilation, careful mask ventilation during the apneic phase, and attention to cardiorespiratory status for post-intubation care. CONCLUSION: Using a Delphi method, agreement among a panel of international experts was reached for 53 statements providing guidance to clinicians worldwide on safe tracheal intubation practices in patients with a physiologically difficult airway to help improve patient outcomes. Well-designed studies are needed to assess the effects of these practice statements and address the remaining uncertainties.

A novel two-stage approach to the treatment of renal cell carcinoma with intra-cardiac tumour extension and Budd-Chiari syndrome.

OBJECTIVE: To present the early results of a new technique for the treatment of renal cell carcinoma with intra-cardiac tumour extension and Budd-Chiari syndrome. PATIENTS AND METHODS: The first stage involves transdiaphragmatic debulking of the right heart, inferior vena cava (IVC) and hepatic veins via median sternotomy, followed by a purse-string suture placed in the IVC below the hepatic veins. The second stage is performed separately and involves en bloc resection of the affected kidney, and IVC and vascular reconstruction via an abdominal incision. RESULTS: Three of five patients presented with clinical Budd-Chiari syndrome; two had radiological features only. The median time between surgical procedures was 12 days (IQR 13 days). Four of the five patients had a R0 resection. While all five patients successfully completed both operative stages, one patient died 22 days after the second stage. Of the remaining four, all survive with no disease recurrence. CONCLUSION: While we continue to compile longer-term data for a larger follow-up series, these preliminary findings show the feasibility of this technique and support the development of this programme of surgery.

Low tidal volume ventilation for patients undergoing laparoscopic surgery: a secondary analysis of a randomised clinical trial.

BACKGROUND: We recently reported the results for a large randomized controlled trial of low tidal volume ventilation (LTVV) versus conventional tidal volume (CTVV) during major surgery when positive end expiratory pressure (PEEP) was equal between groups. We found no difference in postoperative pulmonary complications (PPCs) in patients who received LTVV. However, in the subgroup of patients undergoing laparoscopic surgery, LTVV was associated with a numerically lower rate of PPCs after surgery. We aimed to further assess the relationship between LTVV versus CTVV during laparoscopic surgery. METHODS: We conducted a post-hoc analysis of this pre-specified subgroup. All patients received volume-controlled ventilation with an applied PEEP of 5 cmH2O and either LTVV (6 mL/kg predicted body weight [PBW]) or CTVV (10 mL/kg PBW). The primary outcome was the incidence of a composite of PPCs within seven days. RESULTS: Three hundred twenty-eight patients (27.2%) underwent laparoscopic surgeries, with 158 (48.2%) randomised to LTVV. Fifty two of 157 patients (33.1%) assigned to LTVV and 72 of 169 (42.6%) assigned to conventional tidal volume developed PPCs within 7 days (unadjusted absolute difference, - 9.48 [95% CI, - 19.86 to 1.05]; p = 0.076). After adjusting for pre-specified confounders, the LTVV group had a lower incidence of the primary outcome than patients receiving CTVV (adjusted absolute difference, - 10.36 [95% CI, - 20.52 to - 0.20]; p = 0.046). CONCLUSION: In this post-hoc analysis of a large, randomised trial of LTVV we found that during laparoscopic surgeries, LTVV was associated with a significantly reduced PPCs compared to CTVV when PEEP was applied equally between both groups. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry no: 12614000790640.

Characteristics and outcomes of surgical patients admitted to an overnight intensive recovery unit: A retrospective observational study.

Postoperative 'enhanced care' models that sit between critical care and ward-based care may allow for more cost-effective and efficient utilisation of resources for high-risk surgical patients. In this retrospective observational study, we describe an overnight intensive recovery model in a tertiary hospital, termed 'recovery high dependency unit', and the characteristics, treatment, disposition at discharge and in-hospital outcomes of patients admitted to this unit. We included all adult patients (≥18 years) admitted to the recovery high dependency unit for at least one hour between July 2017 and June 2020. Over this three-year period, 1257 patients were included in the study. The median length of stay in the recovery high dependency unit was 12.6 (interquartile range 9.1-15.9) hours and the median length of hospital stay was 8.3 (interquartile range 5.0-17.3) days. Hospital discharge data showed that 1027 (81.7%) patients were discharged home and that 37 (2.9%) patients died. Non-invasive ventilation was delivered to 59 (4.7%) patients and 290 (23.1%) required vasopressor support. A total of 164 patients (13.0%) were admitted to the intensive care unit following their recovery high dependency unit admission. Of the 1093 patients who were discharged to the ward, 70 patients (6.4%) had a medical emergency team call within 24 hours of discharge from the recovery high dependency unit. In this study of a recovery high dependency unit patient cohort, there was a relatively low need for intensive care unit admission postoperatively and a very low incidence of medical emergency team calls post-discharge to the ward. Other institutions may consider the introduction and evaluation of this model in the care of their higher risk surgical patients.

Intraoperative low tidal volume ventilation and the risk of ICD-10 coded delirium and the use for antipsychotic medications.

BACKGROUND: Low tidal volume (VT) ventilation and its associated increase in arterial carbon dioxide (PaCO2) may affect postoperative neurologic function. We aimed to test the hypothesis that intraoperative low VT ventilation affect the incidence of postoperative ICD-10 coded delirium and/or the need for antipsychotic medications. METHODS: This is a post-hoc analysis of a large randomized controlled trial evaluating low vs. conventional VT ventilation during major non-cardiothoracic, non-intracranial surgery. The primary outcome was the incidence of ICD-10 delirium and/or the use of antipsychotic medications during hospital stay, and the absolute difference with its 95% confidence interval (CI) was calculated. RESULTS: We studied 1206 patients (median age of 64 [55-72] years, 59.0% males, median ARISCAT of 26 [19-37], and 47.6% of ASA 3). ICD-10 coded delirium and /or antipsychotic medication use was diagnosed in 11.2% with similar incidence between low and conventional VT ventilation (11.1% vs. 11.3%; absolute difference, -0.24 [95%CI, -3.82 to 3.32]; p = 0.894). There was no interaction between allocation group and type of surgery. CONCLUSION: In adult patients undergoing major surgery, low VT ventilation was not associated with increased risk of ICD-10 delirium and/or the use of antipsychotic medications during hospital stay. TRIAL REGISTRATION: ANZCTR Identifier: ACTRN12614000790640 .

Intra-operative ventilator mechanical power as a predictor of postoperative pulmonary complications in surgical patients: A secondary analysis of a randomised clinical trial.

BACKGROUND: Studies in critically ill patients suggest a relationship between mechanical power (an index of the energy delivered by the ventilator, which includes driving pressure, respiratory rate, tidal volume and inspiratory pressure) and complications. OBJECTIVE: We aimed to assess the association between intra-operative mechanical power and postoperative pulmonary complications (PPCs). DESIGN: Post hoc analysis of a large randomised clinical trial. SETTING: University-affiliated academic tertiary hospital in Melbourne, Australia, from February 2015 to February 2019. PATIENTS: Adult patients undergoing major noncardiothoracic, nonintracranial surgery. INTERVENTION: Dynamic mechanical power was calculated using the power equation adjusted by the respiratory system compliance (CRS). Multivariable models were used to assess the independent association between mechanical power and outcomes. MAIN OUTCOME MEASURES: The primary outcome was the incidence of PPCs within the first seven postoperative days. The secondary outcome was the incidence of acute respiratory failure. RESULTS: We studied 1156 patients (median age [IQR]: 64 [55 to 72] years, 59.5% men). Median mechanical power adjusted by CRS was 0.32 [0.22 to 0.51] (J min-1)/(ml cmH2O-1). A higher mechanical power was also independently associated with increased risk of PPCs [odds ratio (OR 1.34, 95% CI, 1.17 to 1.52); P < 0.001) and acute respiratory failure (OR 1.40, 95% CI, 1.21 to 1.61; P < 0.001). CONCLUSION: In patients receiving ventilation during major noncardiothoracic, nonintracranial surgery, exposure to a higher mechanical power was independently associated with an increased risk of PPCs and acute respiratory failure. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Registry no: 12614000790640.

Effect of Intraoperative Low Tidal Volume vs Conventional Tidal Volume on Postoperative Pulmonary Complications in Patients Undergoing Major Surgery: A Randomized Clinical Trial.

Importance: In patients who undergo mechanical ventilation during surgery, the ideal tidal volume is unclear. Objective: To determine whether low-tidal-volume ventilation compared with conventional ventilation during major surgery decreases postoperative pulmonary complications. Design, Setting, and Participants: Single-center, assessor-blinded, randomized clinical trial of 1236 patients older than 40 years undergoing major noncardiothoracic, nonintracranial surgery under general anesthesia lasting more than 2 hours in a tertiary hospital in Melbourne, Australia, from February 2015 to February 2019. The last date of follow-up was February 17, 2019. Interventions: Patients were randomized to receive a tidal volume of 6 mL/kg predicted body weight (n = 614; low tidal volume group) or a tidal volume of 10 mL/kg predicted body weight (n = 592; conventional tidal volume group). All patients received positive end-expiratory pressure (PEEP) at 5 cm H2O. Main Outcomes and Measures: The primary outcome was a composite of postoperative pulmonary complications within the first 7 postoperative days, including pneumonia, bronchospasm, atelectasis, pulmonary congestion, respiratory failure, pleural effusion, pneumothorax, or unplanned requirement for postoperative invasive or noninvasive ventilation. Secondary outcomes were postoperative pulmonary complications including development of pulmonary embolism, acute respiratory distress syndrome, systemic inflammatory response syndrome, sepsis, acute kidney injury, wound infection (superficial and deep), rate of intraoperative need for vasopressor, incidence of unplanned intensive care unit admission, rate of need for rapid response team call, intensive care unit length of stay, hospital length of stay, and in-hospital mortality. Results: Among 1236 patients who were randomized, 1206 (98.9%) completed the trial (mean age, 63.5 years; 494 [40.9%] women; 681 [56.4%] undergoing abdominal surgery). The primary outcome occurred in 231 of 608 patients (38%) in the low tidal volume group compared with 232 of 590 patients (39%) in the conventional tidal volume group (difference, -1.3% [95% CI, -6.8% to 4.2%]; risk ratio, 0.97 [95% CI, 0.84-1.11]; P = .64). There were no significant differences in any of the secondary outcomes. Conclusions and Relevance: Among adult patients undergoing major surgery, intraoperative ventilation with low tidal volume compared with conventional tidal volume, with PEEP applied equally between groups, did not significantly reduce pulmonary complications within the first 7 postoperative days. Trial Registration: ANZCTR Identifier: ACTRN12614000790640.

Frequency of hyperoxaemia during and after major surgery.

The oxygen concentration (FiO2) and arterial oxygen tension (PaO2) delivered in patients undergoing major surgery is poorly understood. We aimed to assess current practice with regard to the delivered FiO2 and the resulting PaO2 in patients undergoing major surgery. We performed a retrospective cohort study in a tertiary hospital. Data were collected prospectively as part of a larger randomised controlled trial but were analysed retrospectively. Patients were included if receiving controlled mandatory ventilation and arterial line monitoring. Anaesthetists determined the FiO2 and the oxygenation saturation (SpO2) targets. An arterial blood gas (ABG) was obtained 15-20 minutes after induction of anaesthesia, immediately before the emergence phase of anaesthesia and 15 minutes after arrival in the post-anaesthesia care unit (PACU). We defined hyperoxaemia as a PaO2 of >150 mmHg and included a further threshold of PaO2 >200 mmHg. We studied 373 patients. The median (interquartile range (IQR)) lowest intraoperative FiO2 and SpO2 values were 0.45 (IQR 0.4-0.5) and 97% (IQR 96-98%), respectively, with a median PaO2 on the first and second ABG of 237 mmHg (IQR 171-291 mmHg) and 189 mmHg (IQR 145-239 mmHg), respectively. In the PACU, the median lowest oxygen flow rate was 6 L/min (IQR 3-6 L/min), and the PaO2 was 158 mmHg (IQR 120-192 mmHg). Hyperoxaemia occurred in 82%, 73% and 54% of participants on the first and second intraoperative and postoperative ABGs respectively. A PaO2 of >200 mmHg occurred in 64%, 41% and 21% of these blood gases, respectively. In an Australian tertiary hospital, a liberal approach to FiO2 and PaO2 was most common and resulted in a high incidence of perioperative hyperoxaemia.

Low tidal volume ventilation during anaesthesia for major surgery: protocol and statistical analysis plan.

BACKGROUND: Mechanical ventilation is mandatory in patients undergoing general anaesthesia for major surgery. Tidal volumes higher than 10 mL/kg of predicted body weight have been advocated for intraoperative ventilation, but recent evidence suggests that low tidal volumes may benefit surgical patients. To date, the impact of low tidal volume compared with conventional tidal volume during surgery has only been assessed in clinical trials that also combine different levels of positive end-expiratory pressure (PEEP) in each arm. We aimed to assess the impact of low tidal volume compared with conventional tidal volume during general anaesthesia for surgery on the incidence of postoperative respiratory complications in adult patients receiving moderate levels of PEEP. STUDY DESIGN AND METHODS: Single-centre, two-arm, randomised clinical trial. In total, 1240 adult patients older than 40 years scheduled for at least 2 hours of surgery under general anaesthesia and routinely monitored with an arterial line were included. Patients were ventilated intraoperatively with a moderate level of PEEP (5 cmH2O) and randomly assigned to tidal volume of 6 mL/kg predicted body weight (low tidal volume) or 10 mL/kg predicted body weight (conventional tidal volume in Australia). MAIN OUTCOME MEASURE: The primary outcome is the occurrence of postoperative respiratory complications, recorded as a composite endpoint of adverse respiratory events during the first 7 postoperative days. RESULTS AND CONCLUSIONS: This is the first well powered study comparing the effect of low tidal volume ventilation versus high tidal volume ventilation during surgery on the incidence of postoperative respiratory complications in adult patients receiving moderate levels of PEEP. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ACTRN12614000790640).

Comparison of the WarmCloud and Bair Hugger Warming Devices for the Prevention of Intraoperative Hypothermia in Patients Undergoing Orthotopic Liver Transplantation: A Randomized Clinical Trial.

BACKGROUND: The avoidance of hypothermia is vital during prolonged and open surgery to improve patient outcomes. Hypothermia is particularly common during orthotopic liver transplantation (OLT) and associated with undesirable physiological effects that can adversely impact on perioperative morbidity. The KanMed WarmCloud (Bromma, Sweden) is a revolutionary, closed-loop, warm-air heating mattress developed to maintain normothermia and prevent pressure sores during major surgery. The clinical effectiveness of the WarmCloud device during OLT is unknown. Therefore, we conducted a randomized controlled trial to determine whether the WarmCloud device reduces hypothermia and prevents pressure injuries compared with the Bair Hugger underbody warming device. METHODS: Patients were randomly allocated to receive either the WarmCloud or Bair Hugger warming device. Both groups also received other routine standardized multimodal thermoregulatory strategies. Temperatures were recorded by nasopharyngeal temperature probe at set time points during surgery. The primary endpoint was nasopharyngeal temperature recorded 5 minutes before reperfusion. Secondary endpoints included changes in temperature over the predefined intraoperative time points, number of patients whose nadir temperature was below 35.5°C and the development of pressure injuries during surgery. RESULTS: Twenty-six patients were recruited with 13 patients randomized to each group. One patient from the WarmCloud group was excluded because of a protocol violation. Baseline characteristics were similar. The mean (standard deviation) temperature before reperfusion was 36.0°C (0.7) in the WarmCloud group versus 36.3°C (0.6) in the Bairhugger group (P = 0.25). There were no statistical differences between the groups for any of the secondary endpoints. CONCLUSIONS: When combined with standardized multimodal thermoregulatory strategies, the WarmCloud device does not reduce hypothermia compared with the Bair Hugger device in patients undergoing OLT.

Apneic Oxygenation Versus Low-Tidal-Volume Ventilation in Anesthetized Cardiac Surgical Patients: A Prospective, Single-Center, Randomized Controlled Trial.

OBJECTIVES: To compare the physiology of apneic oxygenation with low-tidal-volume (VT) ventilation during harvesting of the left internal mammary artery. DESIGN: Prospective, single-center, randomized trial. SETTING: Single-center teaching hospital. PARTICIPANTS: The study comprised 24 patients who underwent elective coronary artery bypass grafting surgery. INTERVENTIONS: Apneic oxygenation (apneic group: 12 participants) and low-VT ventilation (low-VT group: 12 participants) (2.5 mL/kg ideal body weight) for 15 minutes during harvesting of the left internal mammary artery. MEASUREMENT AND MAIN RESULTS: The primary endpoint was an absolute change in partial pressure of arterial carbon dioxide (PaCO2). Secondary endpoints were changes in arterial pH, pulmonary artery pressures (PAP), cardiac index, and pulmonary artery acceleration time and ease of surgical access. The mean (standard deviation) absolute increase in PaCO2 was 31.8 mmHg (7.6) in the apneic group and 17.6 mmHg (8.2) in the low-VT group (baseline-adjusted difference 14.2 mmHg [95% confidence interval 21.0-7.3], p<0.001). The mean (standard deviation) absolute decrease in pH was 0.15 (0.03) in the apneic group and 0.09 (0.03) in the low-VT group baseline-adjusted difference 0.06 [95% confidence interval 0.03-0.09], p<0.001. Differences in the rate of change over time between groups (time-by-treatment interaction) were observed for PaCO2 (p<0.001), pH (p<0.001), systolic PAP (p = 0.002), diastolic PAP (p = 0.023), and mean PAP (p = 0.034). Both techniques provided adequate ease of surgical access; however, apneic oxygenation was preferred predominantly. CONCLUSIONS: Apneic oxygenation caused a greater degree of hypercarbia and respiratory acidemia compared with low-VT ventilation. Neither technique had deleterious effects on PAP or cardiac function. Both techniques provided adequate ease of surgical access.

Should we induce general anesthesia in the prone position?

PURPOSE OF REVIEW: For patients requiring surgery in the prone position, an alternative to a traditional supine induction is allowing the patient to position themselves comfortably prone and inducing anesthesia in that position. The purpose of this review is to examine the current literature and evaluate the safety of induction of anesthesia in the prone position. RECENT FINDINGS: The first randomized trial comparing induction in the supine vs. prone position for patients requiring spinal surgery was published earlier this year and reported a time-saving benefit. Multiple case series report the feasibility of this approach; however, the potential benefits of prone induction, namely a reduction in pressure injuries and avoidance of complications of the turn itself, remain unproven. Increased familiarity with prone insertion of supraglottic airways is a useful tool in case of accidental intraoperative extubation in a patient who is already prone. Potential disadvantages include loss of the airway during induction, reduced ability to manage adverse hemodynamic consequences of induction and restriction to use of a supraglottic airway. SUMMARY: The reviewed literature shows that elective prone induction of anesthesia using supraglottic airways, in select patients, is feasible and associated with very low complication rates; however, there is insufficient evidence to suggest that this should be done routinely.

A review of video laryngoscopes relevant to the intensive care unit.

The incidence of difficult direct intubation in the intensive care unit (ICU) is estimated to be as high as 20%. Recent advances in video-technology have led to the development of video laryngoscopes as new intubation devices to assist in difficult airway management. Clinical studies indicate superiority of video laryngoscopes relative to conventional direct laryngoscopy in selected patients. They are therefore an important addition to the armamentarium of any clinician performing endotracheal intubation. We present a practical review of commonly available video laryngoscopes with respect to design, clinical efficacy, and safety aspects relevant to their use in the ICU.

Type of anesthesia and postoperative delirium after vascular surgery.

OBJECTIVE: The purpose of this study was to investigate the association between general (GA), regional (RA), and local (LA) anesthetic techniques with respect to the development of delirium after vascular surgery. The authors hypothesized that patients undergoing GA for vascular surgery would have a higher incidence of postoperative delirium. The role of LA with respect to postoperative delirium in vascular surgery patients previously has not been reported. DESIGN: Retrospective review. SETTING: Tertiary referral center, university hospital. PARTICIPANTS: 500 patients undergoing vascular surgical procedures. INTERVENTIONS: Based on the chosen anesthetic technique, all patients were divided into GA, RA, and LA groups, respectively. Exclusion criteria were patients with preoperative dementia or abnormal level of consciousness, patients undergoing open abdominal aneurysm repair surgery, and patients undergoing carotid endarterectomy. All anesthetic techniques were conducted according to routine institutional practices. Patients in both the RA and LA groups received intravenous sedation. MEASUREMENTS AND MAIN RESULTS: Three hundred ninety-six (79%) patients received GA, 73 (15%) RA, and 31 (6%) LA. The overall incidence of delirium was 19.4% and rates were similar among the 3 groups, with 73 (18.4%) patients in the GA group, 17 (23.2%) in the RA group, and 7 (22.5%) in the LA group (p = 0.56). Patients in the LA group were more likely to have emergency surgery and also had a higher incidence of previous cerebrovascular accidents or transient ischemic attacks. There was no significant difference with respect to either onset or duration of delirium among the 3 groups. Median length of hospital stay and in-hospital mortality were similar among the 3 groups. CONCLUSIONS: Delirium rates after vascular surgery were similar with local, regional, or general anesthesia techniques. The presence of risk factors for the development of postoperative delirium should not influence the type of anesthesia provided.

Extubation of a difficult airway after thyroidectomy: use of a flexible bronchoscope via the LMA-Classic™.

PURPOSE: We report an extubation strategy for a patient scheduled for thyroidectomy who had several factors indicating that it would be a difficult extubation. CLINICAL FEATURES: A 75-yr-old man with thyroid cancer presented for total thyroidectomy. He had anatomical features predictive of a difficult upper airway. Therefore, his trachea was intubated while he was awake using a flexible bronchoscope. The tumour had invaded the trachea, necessitating total thyroidectomy, 3-cm tracheal resection, and primary tracheal anastomosis. The left recurrent laryngeal nerve (RLN) was inherently involved in the tumour and sacrificed. A "guardian suture" placed between the chin and the chest maintained the head and neck in flexion, thereby avoiding traction on the tracheal anastomosis. Immediate postoperative extubation was desirable, given the new tracheal anastomosis; however, complicating factors included left RLN paralysis, tracheal anastomosis, potential for tracheomalacia or supraglottic airway swelling, and the guardian suture preventing neck extension. In addition, there were anatomical features raising the suspicion of difficult reintubation should it be necessary. With the patient deeply anesthetized, the endotracheal tube was removed and replaced with the Laryngeal Mask Airway (LMA)-Classic™ as a bridging device to facilitate bronchoscopic examination. It allowed us to visualize the tracheal repair, tracheal movement, vocal cord function, and supraglottic structures. The patient emerged from anesthesia and was extubated uneventfully. CONCLUSION: We describe a viable extubation strategy used in a patient after complex thyroid surgery involving tracheal resection. By using the LMA-Classic™ as a bridging device and to facilitate bronchoscopic examination, we were able to address the above concerns and safely manage the extubation phase in this patient.