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Iron is an essential nutrient for oxygen supply and aerobic metabolism. Iron deficiency impacts cellular respiration and mitochondrial energy metabolism, which can lead to reduced skeletal muscle function and muscle mass, causing sarcopenia. Intravenous iron offers the ability to rapidly correct iron deficiency, but the functional impact on patient mental and physical health is unclear. We assessed the effects of intravenous iron therapy on physical function and quality of life in the treatment of adults with non‐anaemic iron deficiency. An update and reanalysis of a previously published Cochrane systematic review was performed to assess randomized controlled trials that compared any intravenous iron preparation with placebo in adults. The primary functional outcome measure was physical performance as defined by the trial authors. Secondary outcome measures included fatigue and quality‐of‐life scores, and adverse effects at the end of follow‐up. Biochemical efficacy was assessed by change in serum ferritin and haemoglobin concentration levels. Twenty‐one randomized controlled trials, comprising 3514 participants, were included. Intravenous iron compared with placebo resulted in significantly increased physical function measured by mean peak oxygen consumption (mean difference [MD] 1.77 mL/kg/min, 95% confidence interval [CI] 0.57 to 2.97). An overall improvement in fatigue was seen (standardized MD 0.30, 95% CI −0.52 to −0.09) but no overall difference in quality of life (MD 0.15, 95% CI −0.01 to 0.31). Biochemically, intravenous iron resulted in improved serum ferritin (MD 245.52 μg/L, 95% CI 152.1 to 338.9) and haemoglobin levels (MD 4.65 g/L, 95% CI 2.53 to 6.78). There was a higher risk of developing mild adverse events in the intravenous iron group compared with the placebo group (risk ratio 1.77, 95% CI 1.10 to 2.83); however, no differences were seen in serious adverse events (risk difference 0, 95% CI −0.01 to 0.01). The quality of evidence was rated ‘low’ and ‘very low’ for all outcome variables, except for fatigue, mainly due to most studies being judged as having a high risk of bias. In non‐anaemic iron‐deficient adults, the use of intravenous iron compared with placebo improved physical function and reduced fatigue scores. However, we remain uncertain about the efficacy in this population due to low‐quality evidence, and there is a need for further studies to address potential impact on overall quality of life.

One in two adults undergoing cardiac surgery are iron deficient, best practice guidelines and consensus statements recommend routine investigation and treatment of iron deficiency before elective cardiac surgery, even in the absence of anaemia; however, it is not clear if non-anaemic iron deficiency is associated with worse outcomes in this patient population. We hypothesised that iron deficiency would be associated with worse postoperative outcomes than an iron replete state in adults without anaemia undergoing elective cardiac surgery.

Powered air-purifying respirators (PAPR) are a high level of respiratory personal protective equipment. Like all mechanical devices, they are vulnerable to failure. The precise physiological consequences of failure in live subjects have not previously been reported. We conducted an observational safety study simulating PAPR failure in a group of nine healthy volunteers, wearing loose-fitting hoods, who were observed for a period of ten minutes, or until they requested the experiment be aborted, with continuous monitoring of gas exchange. Relative to baseline, participants demonstrated median reductions in peripheral oxygen saturation of 3.5% (95% confidence interval (CI) –4% to –2%; P= 0.0039) and fraction of inspired oxygen of 0.045 (95% CI –0.05 to –0.04; P= 0.0039), and median increases in inspired partial pressure of carbon dioxide of 27 mmHg (95% CI 23.5–32 mmHg; P= 0.0039), end-tidal partial pressure of carbon dioxide of 11 mmHg (95% CI 7–16 mmHg; P= 0.0039) and minute ventilation of 30 l/min (95% CI 19.4–35.9 l/min; P= 0.0039). Median collateral entrainment of room air into the hood was 17.6 l/min (interquartile range 12.3–27.0 l/min). All subjects reported thermal discomfort, with two (22.2%) requesting early termination of the experiment. Whilst the degree of rebreathing in this experiment was not sufficient to cause dangerous physiological derangement, the degree of reported thermal discomfort combined with the consequences of entrainment of possibly contaminated air into the hood, pose a risk to wearers in the event of failure.

Perioperative risk assessment is complex in patients with chronic obstructive pulmonary disease who have undergone previous lung resection surgery. A 70-year-old female with severe chronic obstructive pulmonary disease and previous right middle and lower lobectomy, presented for left lower lobe superior segmentectomy. Respiratory function tests revealed a forced expiratory volume in 1 second of 0.72L, a forced vital capacity of 1.93L, and a carbon monoxide transfer factor of 10.0 ml/min/mmHg. A cardiopulmonary exercise test demonstrated little ventilatory reserve with profound arterial desaturation on peak exercise, however, a normal peak oxygen consumption (16.7 ml/min/kg) and a nadir minute ventilation/carbon dioxide slope of 24 implied a limited risk of perioperative cardiovascular morbidity. Given these conflicting results we performed an intraoperative oxygen challenge test under general anaesthesia with sequential ventilation of different lobes of the lung. We demonstrate the use of the oxygen challenge test as an effective intervention to further assess safety and tolerance of anaesthesia of patients with limited respiratory reserve being assessed for further complex redo lung resection surgery. Further, this test was a risk stratification tool that allowed informed decisions to be made by the patient about therapeutic options for treating their lung cancer. The prognostic value of traditional physiological parameters in patients with chronic obstructive pulmonary disease who have undergone previous lung resection surgery is uncertain. The intraoperative oxygen challenge test is another risk stratification tool to assist clinicians in assessment of safety and tolerance of anaesthesia for patients being considered for lung resection.

Despite the ubiquitous use of cardioplegia in cardiac surgery, there is a lack of agreement on various aspects of cardioplegia practice. To discover current cardioplegia practices throughout the world, we undertook a global survey to document contemporary cardiopulmonary bypass practices. A 16-question, Internet-based survey was distributed by regional specialist societies, targeting adult cardiac anesthesiologists. Ten questions concerned caseload and cardioplegia practices, the remaining questions examined anticoagulation and pump-priming practices. The survey was available in English, Spanish, and Portuguese. The survey was launched in June 2015 and remained open until May 2016. A total of 923 responses were analyzed, summarizing practice in Europe (269), North America (334), South America (215), and Australia/New Zealand (105). Inter-regional responses differed for all questions asked (p< .001). In all regions other than South America, blood cardioplegia was the common arrest technique used. The most commonly used cardioplegia solutions were: St. Thomas, Bretschneider, and University of Wisconsin with significant regional variation. The use of additives (most commonly glucose, glutamate, tris-hydroxymethyl aminomethane, and aspartate) varied significantly. This survey has revealed significant variation in international practice with regards to myocardial protection, and is a reminder that there is no clear consensus on the use of cardioplegia. It is unclear why regional practice groups made the choices they have and the clinical impact remains unclear.

Iron deficiency is common in colorectal cancer. Despite perioperative guidelines advocating for the correction of non-anaemic iron deficiency prior to major surgery, the impact of this pathology on postoperative outcome is unclear.We conducted a single-centre, historical cohort study of 141 elective resections for colorectal cancer. We stratified non-anaemic patients into iron deficient and iron replete groups, and collected data on baseline characteristics, preoperative laboratory results, intraoperative events and postoperative outcomes. As this study was an exploratory work for future research, a P-value of 0.25 was considered relevant. Patients in the deficient group demonstrated lower baseline ferritin (median (interquartile range, IQR) 76 (41–141) µg/L versus 207 (140–334) µg/L, P< 0.001) and transferrin saturation (mean (standard deviation, SD) 18% (8%) versus 32% (12%), P< 0.001) than those in the replete group, and lower starting haemoglobin (mean (SD) 138 (10) g/L versus 144 (12) g/L, P= 0.01). The deficient group had increased re-admission (25% (24%) versus 4% (11%), P= 0.15) and all-cause infection (25% (24%) versus 5% (14%), P= 0.24). A decrease of two days in days alive and out of hospital at postoperative day 90 was seen in the deficient group on univariate analysis (median (IQR) 81 (75–84) versus 83 (78–84), P= 0.25). This reduced to 1.24 days in multivariate adjusted quantile regression analysis (P= 0.22). Days alive and out of hospital at day 90, postoperative re-admission and postoperative infection may be meaningful outcome measures for future prospective observational work examining non-anaemic iron deficiency in patients undergoing major surgery for colorectal cancer.

Supplemental Digital Content is available in the text.Published ahead of print June 12, 2017.

Supplemental Digital Content is available in the text.Published ahead of print January 19, 2017.

Objective: To define the relationship between worsening oxygenation status (worst PaO2/FiO2ratio in the first 24 hours after intensive care unit admission) and mortality in immunosuppressed and immunocompetent ICU patients in the presence and absence of mechanical ventilation.

Published ahead of print June 14, 2017.