Professor John F. Nunn: scientist, anaesthetist and polymath.

John Francis Nunn (1925-2022) was an anaesthetist and clinical scientist who used his incomprehension of the science of anaesthesia in his early career to guide an extensive lifetime of innovative research. His interests outside of medicine led to him developing renowned expertise in such diverse areas as Egyptian hieroglyphs and the origins of the Earth's atmosphere. He was an outstanding communicator, writing four books alongside an impressive number of papers covering diverse topics from cell biology to history. His greatest contribution is in the understanding of respiratory physiology during anaesthesia which continues to underpin current routine anaesthetic practice and patient safety.

Investigating the causes of patient anxiety at induction of anaesthesia: A mixed methods study.

AIM: To investigate patient anxiety at anaesthetic induction and whether this is affected by anaesthetic room interventions. METHODS: A mixed methods study was carried out: pre-induction interventions were directly observed. Patient anxiety was assessed quantitatively with cardiovascular changes, the visual analogue scale and the state-trait anxiety inventory. Interviews allowed qualitative assessment. RESULTS: Patient-reported anxiety did not correlate with cardiovascular changes. Anaesthetic room interventions were not predictive of anxiety. Postoperative interviews identified five sources of anxiety, mostly related to preparation for surgery. Staff responses to anxiety were also highlighted. DISCUSSION: Patient-reported anxiety and its biological response are not correlated. Pre-induction interventions do not contribute to anxiety. Anxiety levels at induction are similar to or lower than earlier in the preoperative period. CONCLUSIONS: On induction of anaesthesia, patients have little control over their situation but are actively reassured and distracted by theatre staff. Our data suggest staff are good at this. More could still be done to reduce preoperative sources of anxiety.

A pilot investigation into the effects of acute normobaric hypoxia, high altitude exposure and exercise on serum angiotensin-converting enzyme, aldosterone and cortisol.

INTRODUCTION: Aldosterone decreases at high altitude (HA) but the effect of hypoxia on angiotensin-converting enzyme (ACE), a key step in the renin-angiotensin-aldosterone system, is unclear. METHODS: We investigated the effects of exercise and acute normobaric hypoxia (NH, ~11.0% FiO2) on nine participants and six controls undertaking the same exercise at sea level (SL). NH exposure lasted 5 hours with 90 minutes of submaximal treadmill walking. Blood samples for aldosterone, ACE and cortisol were taken throughout exposure and at rest during a trek to HA (5140 m) in eight separate participants. RESULTS: There was no difference in cortisol or aldosterone between groups pre-exercise. Aldosterone rose with exercise to a greater extent at SL than in NH (post-exercise: 700 ± 325 versus 335 ± 238 pmol/L, mean ± SD, p = 0.044). Conversely, cortisol rose to a greater extent in NH (post-exercise: 734 ± 165 versus 344 ± 159 nmol/L, mean ± SD, p = 0.001). There were no differences in ACE activity. During the trek to HA, resting aldosterone and cortisol reduced with no change in ACE. CONCLUSIONS: Acute NH subdues the exercise-associated rise in aldosteroe but stimulates cortisol, whereas prolonged exposure at HA reduces both resting aldosterone and cortisol. As ACE activity was unchanged in both environments, this is not the mechanism underlying the fall in aldosterone.

Posttraumatic Growth and Bereavement: The Contribution of Self-Determination Theory.

No research drawing from Self-Determination Theory has investigated the bereavement experience of individuals or how motivation can help facilitate posttraumatic growth (PTG) following the death of a loved one. In two cross-sectional studies, university students completed an online survey. Study 1 investigated the contribution of global autonomous and controlled motivation in statistically predicting PTG above and beyond previously researched correlates. Study 2 explored the mediating role of cognitive appraisals and coping in explaining the relationship between global motivation orientations and PTG. Results indicated that in comparison to controlled motivation, autonomous motivation was positively related PTG, even after controlling for previously researched correlates. Mediation results indicated an indirect effect of global autonomous motivation on PTG through task-oriented coping. Collectively, these findings suggest the importance of incorporating motivation into models of PTG. Clinical implications of these findings are also discussed.

Enhanced recovery pathway versus standard care in patients undergoing video-assisted thoracoscopic lobectomy.

OBJECTIVE: The objective of this study was to compare outcomes after video-assisted thoracoscopic lobectomy or segmentectomy before and after introduction of an enhanced recovery program. METHODS: Data from 600 patients undergoing video-assisted lobectomy or segmentectomy between April 2014 and January 2017 were analyzed. A comparative analysis was performed between patients undergoing operation before (365 patients) and after (235 patients) the start of the enhanced recovery program. The incidence of cardiopulmonary complications and 30-day and 90-day mortality, postoperative length of stay, and 30-day and 90-day hospital readmission rates were evaluated. Risk-adjusted cardiopulmonary morbidity and 30-day mortality were calculated for each group and compared. RESULTS: The 2 groups had a similar postoperative length of stay (enhanced recovery pathway median 5 days vs pre-enhanced recovery pathway 4, P = .44), cardiopulmonary complication rates (enhanced recovery pathway 22.6% vs pre-enhanced recovery pathway 22.4%, P = .98), 30-day mortality rates (enhanced recovery pathway 3.8% vs pre-enhanced recovery pathway 2.2%, P = .31), and 90-day mortality rates (enhanced recovery pathway 4.7% vs pre-enhanced recovery pathway 3.0%, P = .37). No differences were noted in terms of 30-day (enhanced recovery pathway 7.2% vs pre-enhanced recovery pathway 7.4%, P = .94) or 90-day readmission rates (enhanced recovery pathway 9.8% vs pre-enhanced recovery pathway 12.3%, P = .34). The risk-adjusted cardiopulmonary morbidity rates were similar in the 2 periods (P = .76), whereas the risk-adjusted 30-day mortality was higher in the enhanced recovery pathway period compared with the pre-enhanced recovery pathway mortality (P = .0004). CONCLUSIONS: We found no benefit conferred by the enhanced recovery program on outcomes such as cardiopulmonary complications, 30- and 90-day mortality, length of stay, and readmissions. Enhanced recovery program elements may be insufficiently different than previous standards of perioperative care to confer detectable benefits in our settings.

Hypoxic pulmonary vasoconstriction: physiology and anesthetic implications.

Hypoxic pulmonary vasoconstriction (HPV) represents a fundamental difference between the pulmonary and systemic circulations. HPV is active in utero, reducing pulmonary blood flow, and in adults helps to match regional ventilation and perfusion although it has little effect in healthy lungs. Many factors affect HPV including pH or PCO2, cardiac output, and several drugs, including antihypertensives. In patients with lung pathology and any patient having one-lung ventilation, HPV contributes to maintaining oxygenation, so anesthesiologists should be aware of the effects of anesthesia on this protective reflex. Intravenous anesthetic drugs have little effect on HPV, but it is attenuated by inhaled anesthetics, although less so with newer agents. The reflex is biphasic, and once the second phase becomes active after about an hour of hypoxia, this pulmonary vasoconstriction takes hours to reverse when normoxia returns. This has significant clinical implications for repeated periods of one-lung ventilation.

Electives in undergraduate medical education: AMEE Guide No. 88.

This Guide outlines the scope and potential roles an elective can contribute to undergraduate medical training and identifies ways to maximize learning opportunities, including within global health. The types of educational activity available for electives range from meeting individual educational need through to exploration of potential career pathways, with many factors influencing choice. Key areas of organization underpinning a successful elective before, during and after the placement include developing clarity of the intended educational outcomes as well as addressing practicalities such as travel and accommodation. Risk management including the implications for the participating schools as well as the student and their elective supervisors is crucial. This Guide would not be complete without some discussion around ethics and professional conduct during an elective, with consideration of the impact of elective placements, particularly in low-middle income countries.

Perioperative oxygen toxicity.

This article challenges the use of hyperoxia in the perioperative period. It describes the biochemical and physiologic basis for both the direct and indirect adverse effects of oxygen. The reasons for using hyperoxia in the perioperative period are critically evaluated, and the evidence and guidelines for oxygen use in common acute medical conditions are reviewed.

Relative reinforcing value of energy-dense snack foods in overweight and obese adults.

PURPOSE: Obese people find energy-dense food more reinforcing than do their non-obese peers, and reinforcement influences food intake. We examined how the degree of adiposity, measured by body mass index (BMI), is associated with the relative reinforcing value of energy-dense snack foods versus fruits and vegetables in overweight and obese people. METHODS: Ninety-two overweight or obese students in introductory psychology courses completed questionnaires on age, sex, BMI, hunger, smoking status, dietary restraint, and hedonic (liking) ratings for energy-dense snack foods and fruits and vegetables. The questionnaire also was used to evaluate the relative reinforcing value of these snack foods in comparison with fruits and vegetables. RESULTS: The BMI predicted the relative reinforcing value of energy-dense snack food. This positive relationship remained significant after we controlled for age, sex, dietary restraint, hunger, smoking status, and snack food hedonics. CONCLUSIONS: The greater the degree of overweight and obesity, the greater the motivation to obtain energy-dense snack foods. Because the rewarding value of food is a strong determinant of energy intake, a useful approach to preventing and treating obesity may be introducing pharmacological or behavioural nutrition intervention to reduce the rewarding value of energy-dense snack foods, or increasing the rewarding value of fruits and vegetables.

Equity in interviews: do personal characteristics impact on admission interview scores?

CONTEXT: Research indicates that some social groups are disadvantaged by medical school selection systems. The stage(s) of a selection process at which this occurs is unknown, but at interview, when applicant and interviewer are face-to-face, there is potential for social bias to occur. METHODS: We performed a detailed audit of the interview process for a single-entry year to a large UK medical school. Our audit included investigating the personal characteristics of both interviewees and interviewers to find out whether any of these factors, including the degree of social matching between individual pairs of interviewees and interviewers, influenced the interview scores awarded. RESULTS: A total of 320 interviewers interviewed 734 applicants, providing complete data for 2007 interviewer-interviewee interactions. The reliability of the interview process was estimated using generalisability theory at 0.82-0.87. For both interviewers and interviewees, gender, ethnic background, socio-economic group and type of school attended had no influence on the interview scores awarded or achieved. Staff and student interviewer marks did not differ significantly. Although numbers in each group of staff interviewers were too small for formal statistical analysis, there were no obvious differences in marks awarded between different medical specialties or between interviewers with varying amounts of interviewing experience. CONCLUSIONS: Our data provide reassurance that the interview does not seem to be the stage of selection at which some social groups are disadvantaged. These results support the continued involvement of senior medical students in the interview process. Despite the lack of evidence that an interview is useful for predicting future academic or clinical success, most medical schools continue to use interviews as a fundamental component of their selection process. Our study has shown that at least this arguably misplaced reliance upon interviewing is not introducing further social bias into the selection system.

Effects of increased inspired oxygen concentration on tissue oxygenation: theoretical considerations.

BACKGROUND AND OBJECTIVES: Breathing increased fractional oxygen concentration (FiO2) is recommended for the treatment of tissue ischaemia. METHODS: The theoretical benefits of increasing FiO2 on tissue oxygenation were evaluated using standard physiological equations. Assuming constant oxygen consumption by tissues throughout the length of a capillary, the oxygen content at 20 arbitrary points along a capillary was calculated. Using mathematical representations of the haemoglobin dissociation curve and an iterative approach to include the dissolved oxygen component of oxygen content, the oxygen partial pressure (PO2) profile along a capillary was estimated. RESULTS: High FiO2 concentrations cause large increases in PO2 at the arteriolar end of capillaries but these large PO2 values, caused by the extra dissolved oxygen, rapidly decline along the capillary. At the venular end of the capillary (the area of tissue most likely to be hypoxic), breathing oxygen causes only a modest improvement in PO2. CONCLUSION: Increasing FiO2 to treat tissue hypoxia has clear benefits, but a multimodal approach to management is required.

Effects of dietary restraint and body mass index on the relative reinforcing value of snack food.

The present study examined the independent and interactive association between dietary restraint, body mass index (BMI) and the relative reinforcing value of food. Four hundred and three introductory psychology students completed questionnaires assessing age, gender, BMI, hunger, smoking status, nicotine dependence, dietary restraint, hedonic ratings for snack food and fruits and vegetables and the relative reinforcing value of snack food and fruits and vegetables. In the overall sample, results indicated a dietary restraint x BMI interaction after controlling for age, hunger, nicotine dependence, and hedonics. However, when regression models were separated by gender, the BMI x restraint interaction emerged only for females and not for males. Findings suggest that BMI moderates the relationship between dietary restraint and snack food reinforcement in females only, such that restraint and snack food reinforcement are inversely correlated in females with lower BMI, but restraint is positively correlated with snack food reinforcement in females with higher BMI. Theoretical and clinical implications of these findings are discussed.

Effects of school-based interventions on mental health stigmatization: a systematic review.

Stigmatizing, or discriminatory, perspectives and behaviour, which target individuals on the basis of their mental health, are observed in even the youngest school children. We conducted a systematic review of the published and unpublished, scientific literature concerning the benefits and harms of school-based interventions, which were directed at students 18 years of age or younger to prevent or eliminate such stigmatization. Forty relevant studies were identified, yet only a qualitative synthesis was deemed appropriate. Five limitations within the evidence base constituted barriers to drawing conclusive inferences about the effectiveness and harms of school-based interventions: poor reporting quality, a dearth of randomized controlled trial evidence, poor methods quality for all research designs, considerable clinical heterogeneity, and inconsistent or null results. Nevertheless, certain suggestive evidence derived both from within and beyond our evidence base has allowed us to recommend the development, implementation and evaluation of a curriculum, which fosters the development of empathy and, in turn, an orientation toward social inclusion and inclusiveness. These effects may be achieved largely by bringing especially but not exclusively the youngest children into direct, structured contact with an infant, and likely only the oldest children and youth into direct contact with individuals experiencing mental health difficulties. The possible value of using educational activities, materials and contents to enhance hypothesized benefits accruing to direct contact also requires investigation. Overall, the curriculum might serve as primary prevention for some students and as secondary prevention for others.

Smoking, dietary restraint, gender, and the relative reinforcing value of snack food in a large university sample.

The present study examined the independent and interactive association between smoking, gender, dietary restraint and the relative reinforcing value of snack food in a university sample. Four hundred and three introductory psychology students completed questionnaires assessing age, gender, BMI, hunger, smoking status, nicotine dependence, dietary restraint, hedonic ratings and the relative reinforcing value of snack food and fruits and vegetables. The relative reinforcing value of snack food was determined by the number of button presses subjects would be willing to do to obtain (100g) of snack food versus 100g of fruits and vegetables. Multiple regression analyses yielded a significant three-way interaction of gender, restraint, and smoking in predicting the relative reinforcing value of snack food indicating that in female smokers, dietary restraint was inversely associated with the relative reinforcing value of snack food, whereas in male smokers, restraint was not significantly related with the reinforcing value of snacks. These findings remained significant after controlling for BMI, hunger, and hedonics, suggesting that there are gender differences in relationship between smoking, dietary restraint, and snack food reinforcement. Among female university students, smoking moderates the relationship between dietary restraint and food reinforcement whereby high-restraint female smokers appear to be at lower risk of over-consuming energy dense snack food compared to low-restraint female smokers, while high-restraint male smokers may not be at higher risk than low-restraint male smokers.

Effects of modifying physical activity and sedentary behavior on psychosocial adjustment in overweight/obese children.

OBJECTIVES: To evaluate the relationship between changes in physical activity (PA), sedentary behavior, and physical self-perceptions and global self-worth in 30, 8-12 years old, overweight/obese children (13 boys, 17 girls). METHODS: Secondary analyses from a randomized controlled trial designed to increase PA and reduce sedentary behavior. PA was measured by accelerometers worn by participants every day for 8 weeks. Sedentary behavior, defined as minutes per day spent in television viewing, was assessed by self-report. RESULTS: Increases in PA were associated with increases in perceived physical conditioning (r = .54, p < .01), body satisfaction (r = .55, p < .01), and overall physical self-worth (r = .44, p < .05) independent of changes in body mass index (BMI). Reductions in TV viewing were also related to increased physical and global self-worth. CONCLUSIONS: Increases in PA are associated with improvements in physical self-perceptions but not global self-worth, while reductions in TV viewing are associated with increased physical and global self-worth, and these psychosocial benefits appear to be independent of changes in adiposity.

Effects of open-loop feedback on physical activity and television viewing in overweight and obese children: a randomized, controlled trial.

OBJECTIVES: Television viewing and physical inactivity increase the risk of obesity in youth. Thus, identifying new interventions that increase physical activity and reduce television viewing would be helpful in the prevention and treatment of pediatric obesity. This study evaluated the effects of open-loop feedback plus reinforcement versus open-loop feedback alone on physical activity, targeted sedentary behavior, body composition, and energy intake in youth. METHODS: Thirty overweight or obese 8- to 12-year-old children were randomly assigned to an intervention (n = 14) or control group (n = 16). Participants wore accelerometers every day for 8 weeks and attended biweekly meetings to download the activity monitors. For children in the open-loop feedback plus reinforcement (intervention) group, accumulating 400 counts of physical activity on pedometers earned 1 hour of television/VCR/DVD time, which was controlled by a Token TV electronic device. Open-loop feedback control subjects wore activity monitors but had free access to targeted sedentary behavior. RESULTS: Compared with controls, the open-loop feedback plus reinforcement group demonstrated significantly greater increases in daily physical activity counts (+65% vs +16%) and minutes per day of moderate-to-vigorous physical activity (+9.4 vs +0.3) and greater reductions in minutes per day spent in television viewing (-116.1 vs +14.3). The intervention group also showed more favorable changes in body composition, dietary fat intake, and energy intake from snacks compared with controls. Reductions in sedentary behavior were directly related to reductions in BMI, fat intake, snack intake, and snack intake while watching television. CONCLUSIONS: Providing feedback of physical activity in combination with reinforcing physical activity with sedentary behavior is a simple method of modifying the home environment that may play an important role in treating and preventing child obesity.

Effects of breastfeeding on weight changes in family-based pediatric obesity treatment.

Research indicates that breastfeeding may provide protective effects against the development of obesity; however, breastfed children may still become obese because of the obesogenic environment. This study is designed to examine the effects of retrospective recall of breastfeeding on weight changes in children participating in a 6-month behavioral treatment program for childhood obesity. The independent variable of breastfeeding was defined as children who were exclusively breastfed for 4 weeks (excluding water or medication) versus those who were never breastfed. Child percent overweight and body mass index changes during 6 and 12 months were evaluated for 94 families based on mother report of breastfeeding status using analysis of covariance, controlling for socioeconomic status and initial child weight status. Data were compiled for secondary analysis from pediatric obesity randomized controlled outcome studies evaluating core components of family-based treatments. Results showed that, compared with nonbreastfed (formula) children (n = 28), breastfed children (n = 66) showed significantly larger reductions in (mean +/- SEM) percent overweight at 6 months (-15.2 +/- 1.1 vs -10.2 +/- 1.7, p <.05) and 1 year (-10.3 +/- 1.3 vs -5.9 +/- 1.8, p <.05). Similarly, breastfed children showed greater reductions in body mass index at 6 months (-2.1 +/- 0.19 vs -1.1 +/- 0.28) and 1 year (-0.8 +/- 0.23 vs +0.1 +/- 0.32). Findings suggest the beneficial effects of breastfeeding may extend beyond obesity prevention to include improved outcome in family-based pediatric obesity treatment. Potential mechanisms relating breastfeeding, obesity prevention, and enhanced outcome in pediatric obesity treatment are discussed.

Comparison of academic, application form and social factors in predicting early performance on the medical course.

OBJECTIVES: To compare the relative importance of social, academic and application form factors at admission in predicting performance in the first 3 years of a medicine course. DESIGN: Retrospective cohort study. SETTING: A single UK medical school. PARTICIPANTS: A total of 738 students who entered medical school between 1994 and 1997. MAIN OUTCOME MEASURE: Performance in Year 3 objective structured clinical examination (OSCE). RESULTS: School-leaving grades were significant predictors of success in the OSCE. Non-academic activities as assessed from the application form were associated with poorer performance. Mature students performed extremely well, and male and ethnic minority students performed less well. Socioeconomic status and type of school attended were not found to affect performance on the course. CONCLUSIONS: The relatively poor performance of male and ethnic minority students urgently needs further investigation. Our results carry no suggestion that, other things being equal, widening access to medical school for mature students and those from less affluent backgrounds would result in poorer performance.