Jai Darvall

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.

The Melbourne epidemic thunderstorm asthma event 2016: an investigation of environmental triggers, effect on health services, and patient risk factors

BACKGROUND A multidisciplinary collaboration investigated the worlds largest, most catastrophic epidemic thunderstorm asthma event that took place in Melbourne, Australia, on Nov 21, 2016, to inform mechanisms and preventive strategies. METHODS Meteorological and airborne pollen data, satellite-derived vegetation index, ambulance callouts, emergency department presentations, and data on hospital admissions for Nov 21, 2016, as well as leading up to and following the event were collected between Nov 21, 2016, and March 31, 2017, and analysed. We contacted patients who presented during the epidemic thunderstorm asthma event at eight metropolitan health services (each including up to three hospitals) via telephone questionnaire to determine patient characteristics, and investigated outcomes of intensive care unit (ICU) admissions. FINDINGS Grass pollen concentrations on Nov 21, 2016, were extremely high (>100 grains/m3). At 1800 AEDT, a gust front crossed Melbourne, plunging temperatures 10°C, raising humidity above 70%, and concentrating particulate matter. Within 30 h, there were 3365 (672%) excess respiratory-related presentations to emergency departments, and 476 (992%) excess asthma-related admissions to hospital, especially individuals of Indian or Sri Lankan birth (10% vs 1%, p<0·0001) and south-east Asian birth (8% vs 1%, p<0·0001) compared with previous 3 years. Questionnaire data from 1435 (64%) of 2248 emergency department presentations showed a mean age of 32·0 years (SD 18·6), 56% of whom were male. Only 28% had current doctor-diagnosed asthma. 39% of the presentations were of Asian or Indian ethnicity (25% of the Melbourne population were of this ethnicity according to the 2016 census, relative risk [RR] 1·93, 95% CI 1·74-2·15, p <0·0001). Of ten individuals who died, six were Asian or Indian (RR 4·54, 95% CI 1·28-16·09; p=0·01). 35 individuals were admitted to an intensive care unit, all had asthma, 12 took inhaled preventers, and five died. INTERPRETATION Convergent environmental factors triggered a thunderstorm asthma epidemic of unprecedented magnitude, tempo, and geographical range and severity on Nov 21, 2016, creating a new benchmark for emergency and health service escalation. Asian or Indian ethnicity and current doctor-diagnosed asthma portended life-threatening exacerbations such as those requiring admission to an ICU. Overall, the findings provide important public health lessons applicable to future event forecasting, health care response coordination, protection of at-risk populations, and medical management of epidemic thunderstorm asthma. FUNDING None.

Chewing gum for the treatment of postoperative nausea and vomiting: a pilot randomized controlled trial

Background. A novel treatment, chewing gum, may be non-inferior to ondansetron in inhibiting postoperative nausea and vomiting (PONV) in female patients after laparoscopic or breast surgery. In this pilot study, we tested the feasibility of a large randomized controlled trial. Methods. We randomized 94 female patients undergoing laparoscopic or breast surgery to ondansetron 4 mg i.v. or chewing gum if PONV was experienced in the postanaesthesia care unit (PACU). The primary outcome was full resolution of PONV, with non-inferiority defined as a difference between groups of <15% in a per protocol analysis. Secondary outcomes were PACU stay duration, anti-emetic rescue use, and acceptability of anti-emetic treatment. The feasibility of implementing the protocol in a larger trial was assessed. Results. Postoperative nausea and vomiting in the PACU occurred in 13 (28%) ondansetron patients and 15 (31%) chewing gum patients (P=0.75). Three chewing gum patients could not chew gum when they developed PONV. On a per protocol basis, full resolution of PONV occurred in five of 13 (39%) ondansetron vs nine of 12 (75%) chewing gum patients [risk difference 37% (6.3–67%), P=0.07]. There was no difference in secondary outcomes between groups. Recruitment was satisfactory, the protocol was acceptable to anaesthetists and nurses, and data collection was complete. Conclusions. In this pilot trial, chewing gum was not inferior to ondansetron for treatment of PONV after general anaesthesia for laparoscopic or breast surgery in female patients. Our findings demonstrate the feasibility of a larger, multicentred randomized controlled trial to investigate this novel therapy. Clinical trial registration. Australian New Zealand Clinical Trials Registry: ACTRN12615001327572.

Influence of ward round order on critically ill patient outcomes

Purpose: To examine the effect of order in which patients are seen on an Intensive Care Unit (ICU) ward round on ICU length of stay (LOS), mortality and duration of mechanical ventilation. Materials and methods: Retrospective observational study in a tertiary metropolitan ICU over a 12 month period. All patients who occupied the first and last three bed spaces of the ICU ward round, without having moved bed spaces during admission, were included. Separate analyses were performed for the absolute first and last patients. Results: 681 patients were included. There was no difference in the primary outcome, ICU LOS [median (IQR) 50 (23−102) hours for the first three patients seen vs. 51 (25–110) hours for the last three patients, p = 0.594]. No differences were found in any secondary outcomes (hospital LOS, ICU mortality or duration of mechanical ventilation). Conclusions: The order in which patients were seen on an ICU ward did not affect ICU LOS nor related outcomes. HIGHLIGHTSThe concept of ‘decision fatigue’ is becoming more apparent in medicine.The effect of the order in which critically ill patients are reviewed on a ward round is unclear.This is the first paper looking into outcome measures and ward round order in critically ill patients.

Acute Pulmonary Embolism: A concise review of diagnosis and management: A review of acute Pulmonary Embolism

An acute pulmonary embolism (aPE) is characterised by occlusion of one or more pulmonary arteries. Physiological disturbance may be minimal, but often cardiac output decreases as the right ventricle attempts to overcome increased afterload. Additionally, ventilation‐perfusion mismatches can develop in affected vascular beds, reducing systemic oxygenation. Incidence is reported at 50–75 per 100 000 in Australia and New Zealand, with 30‐day mortality rates ranging from 0.5% to over 20%. Incidence is likely to increase with the ageing population, increased survival of patients with comorbidities that are considered risk factors and improving sensitivity of imaging techniques. Use of clinical prediction scores, such as the Wells score, has assisted in clinical decision‐making and decreased unnecessary radiological investigations. However, imaging (i.e. computed tomography pulmonary angiography or ventilation‐perfusion scans) is still necessary for objective diagnosis. Anti‐coagulation remains the foundation of PE management. Haemodynamically unstable patients require thrombolysis unless absolutely contraindicated, while stable patients with right ventricular dysfunction or ischaemia should be aggressively anti‐coagulated. Stable patients with no right ventricular dysfunction can be discharged home early with anti‐coagulation and review. However, treatment should be case dependent with full consideration of the patient’s clinical state. Direct oral anti‐coagulants have become an alternative to vitamin K antagonists and are facilitating shorter hospital admissions. Additionally, duration of anti‐coagulation must be decided by considering any provoking factors, bleeding risk and comorbid state. Patients with truly unprovoked or idiopathic PE often require indefinite treatment, while in provoked cases it is typically 3 months with some patients requiring longer periods of 6–12 months.

Discussion about “Association of frailty with short-term outcomes, organ support and resource use in critically ill patients”

Zampieri and colleagues are to be congratulated for their recent study analysing outcomes of almost 130,000 patients across 93 Brazilian ICUs [1]. They found that a higher “modified frailty index” (mFI) was associated with increased mortality and length of stay. Interestingly, organ supports were more common in frail patients, at odds with previous literature, as shown in a 2017 metaanalysis published in this very journal [2]. The question arises as to why this study found differently? To answer this question, we must analyse the components of the “modified frailty index”, and the history of its incorporation in risk assessment. Originally conceived by Tsiouris and colleagues for risk stratification in lung surgery, the mFI was developed by mapping 11 criteria from the original 70-item Canadian Study of Health and Aging to variables in the National Surgical Quality Improvement Program (NSQIP) database [3]. Unsurprisingly, owing to the nature of NSQIP data, only two of the 11 items (“functional status—not independent”, and “impaired sensorium”) are non-comorbid conditions. Thus, the mFI may simply be an aggregate measure of co-morbidities rather than a true frailty measure, which should also have an independent relationship with outcome regardless of age, acute physiological disturbance and comorbidities. In particular, the mFI does not incorporate the six frailty assessment domains recommended by the 2012 Frailty Consensus Conference: physical performance, gait speed, mobility, nutritional status, mental health, and cognition [4]. In light of these concerns, we wonder how the mFI compares with more validated frailty measures such as the Clinical Frailty Scale, or the Fried score. Until such comparisons exist in the ICU population, the use of mFI as a surrogate for frailty and its findings should be viewed and interpreted with great caution.

A frail future

ing correct TT position after fibreoptic intubation requires a three-stage process: capnographic confirmation of ventilation; bronchoscopic visualisation of the carina beyond the TT; and direct (fibreoptic/video) laryngoscopic confirmation of appropriate TT insertion depth. There will be certain scenarios which prevent direct laryngoscopy (e.g. trismus), in which case the operator should retain a high index of clinical suspicion about supraglottic cuff herniation, particularly when high inflating volumes are required to overcome apparent cuff leakage.