Prewarming neurosurgical patients to minimize hypotension on induction of anesthesia: a randomized trial.

PURPOSE: Prewarming prior to surgery is effective in preventing perioperative hypothermia. There is a paucity of evidence, however, regarding the hemodynamic effects of prewarming. We hypothesized that the nadir mean arterial pressure during anesthesia induction would be higher after prewarming than after no prewarming. METHODS: We randomized 32 patients prior to elective neurosurgery to receive either one hour of forced-air convective warming at 46°C or routine care (full body blanket with convective warmer attached but not turned on). All patients had invasive blood pressure, heart rate, and core temperature monitoring before and during warming and underwent a protocolized intravenous anesthetic induction with propofol and remifentanil target-controlled infusions. The primary endpoint was the nadir mean arterial blood pressure (MAP) during induction. Hypotension was defined as systolic blood pressure (SBP) < 90 mmHg, MAP < 60 mmHg, or a reduction in either SBP or MAP > 20% from baseline values. RESULTS: No difference was found in the mean (SD) nadir MAP between the prewarmed group and the control group [64 (11) mmHg vs 68 (16) mmHg, respectively; mean difference, 5 mmHg; 95% confidence interval (CI), -6 to 15; P = 0.36]. Similarly, there was no difference between groups in the incidence of hypotension (100% of prewarmed vs 93% of control patients; relative risk, 1.07; 95% CI, 0.94 to 1.23; P = 0.32) or in the requirement for vasopressors during induction (four patients in each group required metaraminol; P = 1.00). CONCLUSION: Prewarming with convective forced air for one hour prior to intravenous anesthetic induction did not prevent hypotension during the induction period (Australian New Zealand Clinical Trials Registry [ANZCTR] ACTRN12615000431527).

Impact of focused cardiac and lung ultrasound screening performed by a junior doctor during admission to the surgical ward on patients before emergency non-cardiac surgery: A pilot prospective observational study.

Purpose: To assess whether pre-operative focused cardiac ultrasound and lung ultrasound screening performed by a junior doctor can change diagnosis and clinical management of patients aged ≥65 years undergoing emergency, non-cardiac surgery. Method: This pilot prospective observational study included patients scheduled for emergency, non-cardiac surgery. The treating team completed a diagnosis and management plan before and after focused cardiac and lung ultrasound, which was performed by a junior doctor. Changes to diagnosis and management after ultrasound were recorded. Ultrasound images were assessed for image and diagnostic interpretation by an independent expert. Results: There was a total of 57 patients at age 77 ± 8 years. Cardiopulmonary pathology was suspected after clinical assessment in 28% vs. 72% after ultrasound (including abnormal haemodynamic state in 61%, valvular lesions in 32%, acute pulmonary oedema/interstitial syndrome in 9% and bilateral pleural effusions in 2%). In 67% of patients, the perioperative management was changed. The changes were in fluid therapy in 30%, cardiology consultation in 7%, formal in- or out-patient, transthoracic echocardiography in 11% and 30% respectively. Discussion: The impact of pre-operative focused cardiac and lung ultrasound on diagnosis and management of patients on the hospital ward before emergency non-cardiac surgery by a junior doctor was comparable to previous studies of anaesthetists experienced in focused ultrasound. However, the ability to recognise when image quality is insufficient for diagnosis is an important consideration for novice sonographers. Conclusions: Focused cardiac and lung ultrasound examination by a junior doctor is feasible and may change preoperative diagnosis and management in patients of 65 years or older, admitted for emergency non-cardiac surgery.

Cloud-based supervision of training in focused cardiac ultrasound - A scalable solution?

INTRODUCTION/PURPOSE: Increasing demand for training in focused cardiac ultrasound (FCU) is constrained by availability of supervisors to supervise training on patients. We designed and tested the feasibility of a cloud-based (internet) system that enables remote supervision and monitoring of the learning curve of image quality and interpretative accuracy for one novice learner. METHODS: After initial training in FCU (iHeartScan and FCU TTE Course, University of Melbourne), a novice submitted the images and interpretation of 30 practice FCU examinations on hospitalised patients to a supervisor via a cloud-based portal. Electronic feedback was provided by the supervisor prior to the novice performing each FCU examination, which included image quality score (for each view) and interpretation errors. The primary outcome of the study was the number of FCU scans required for two consecutive scans to score: (i) above the lower limit of acceptable total image quality score (64%), and (ii) below the upper limit of acceptable interpretive errors (15%). RESULTS: The number of FCU practice examinations required to meet adequate image quality and interpretation error standard was 10 and 13, respectively. Improvement in image acquisition continued, remaining within limits of acceptable image quality. Conversely, interpretive in-accuracy (error > 15%) continued. CONCLUSION: This electronic FCU mentoring system circumvents (but should not replace) the requirement for bed-side supervision, which may increase the capacity of supervision of physicians learning FCU. The system also allows real-time tracking of their progress and identifies weaknesses that may assist in guiding further training.