Author Archives: Paul Older

Exercise Training Improves Ventilatory Efficiency in Patients With a Small Abdominal Aortic Aneurysm: A RANDOMIZED CONTROLLED STUDY.

J Cardiopulm Rehabil Prev. 2017 Jul 19. doi: 10.1097/HCR.0000000000000270. [Epub
ahead of print]

Lima RM, Vainshelboim B, Ganatra R, Dalman R, Chan K, Myers J.

PURPOSE: To investigate the effects of exercise training on ventilatory
efficiency and physiological responses to submaximal exercise in subjects with
small abdominal aortic aneurysm (AAA).
METHODS: Sixty-five male patients (72.3 ± 7.0 years) were randomized to exercise
training (n = 33) or usual care group (n = 32). Exercise subjects participated in
a training groups for 3 mo. Cardiopulmonary exercise testing was performed before
and after the study period and peak VO2, the ventilatory threshold (VT), the
oxygen uptake efficiency slope (OUES), and the VE2/VCO2 slope were identified.
Baseline work rates at VT were matched to examine cardiopulmonary responses after
training.
RESULTS: Significant interactions indicating improvements before and after
training in the exercise group were noted for time (P < .01), VO2 (P < .01), and
work rate (P < .01) at the VT. At peak effort, significant interactions were
noted for time (P < .01) and work rate (P < .01), while borderline significance
was noted for absolute (P = .07) and relative (P = .04) VO2. Significant
interactions were observed for the OUES both when using all exercise data (P =
.04) and when calculated up to the VT (P < .01). For the VE2/VCO2 slope,
significance was noted only when calculated up to the VT (P = .04). After
training, heart rate, VE, VO2 and respiratory exchange ratio were significantly
attenuated for the same baseline work rate only in the exercise group (all P <
.01).
CONCLUSIONS: Exercise training improves ventilatory efficiency in patients with
small AAA. In addition, patients who exercised exhibited less demanding
cardiorespiratory responses to submaximal effort.

Cardiopulmonary Exercise Testing and Surgery.

Older PO, Levett DZ

Ann Am Thorac Soc. 2017. May 16

The surgical patient population is increasingly elderly and comorbid and poses challenges to perioperative physicians. Accurate pre-operative risk stratification is important to direct perioperative care. Reduced aerobic fitness is associated with increased post-operative morbidity and mortality. Cardiopulmonary exercise testing is an integrated and dynamic test that gives an objective measure of aerobic fitness or functional capacity and identifies the cause of exercise intolerance. Cardiopulmonary exercise testing provides an individualized estimate of patient risk that can be used to predict post-operative morbidity and mortality. This technology can therefore be used to inform collaborative decision making and patient consent; to triage the patient to an appropriate peri-operative care environment; to diagnose unexpected comorbidity; to optimize medical co-morbidities pre-operatively and to direct individualized pre-operative exercise programmes. Functional capacity, evaluated as the anaerobic threshold and peak oxygen uptake (VO2peak) predicts post-operative morbidity and mortality in the majority of surgical cohort studies. The ventilatory equivalents for carbon dioxide (an index of gas exchange efficiency), is predictive of surgical outcome in some cohorts. Prospective cohort studies are needed to improve the precision of risk estimates for different patient groups and to clarify the best combination of variables to predict outcome. Early data suggests that preoperative exercise training improves fitness, reduces the debilitating effects of neoadjuvant chemotherapy and may improve clinical outcomes. Further research is required to identify the most effective type of training and the minimum duration required for a positive effect.

Total haemoglobin mass, but not haemoglobin concentration, is associated with preoperative cardiopulmonary exercise testing-derived oxygen-consumption variables.

Otto JM, Plumb JOM, Wakeham D, et al.

Br J Anaesth. 2017;118(5):747-754

Background: Cardiopulmonary exercise testing (CPET) measures peak exertional oxygen consumption ( V O2peak ) and that at the anaerobic threshold ( V O2 at AT, i.e. the point at which anaerobic metabolism contributes substantially to overall metabolism). Lower values are associated with excess postoperative morbidity and mortality. A reduced haemoglobin concentration ([Hb]) results from a reduction in total haemoglobin mass (tHb-mass) or an increase in plasma volume. Thus, tHb-mass might be a more useful measure of oxygen-carrying capacity and might correlate better with CPET-derived fitness measures in preoperative patients than does circulating [Hb]. Methods: Before major elective surgery, CPET was performed, and both tHb-mass (optimized carbon monoxide rebreathing method) and circulating [Hb] were determined. Results: In 42 patients (83% male), [Hb] was unrelated to V O2 at AT and V O2peak ( r =0.02, P =0.89 and r =0.04, P =0.80, respectively) and explained none of the variance in either measure. In contrast, tHb-mass was related to both ( r =0.661, P <0.0001 and r =0.483, P =0.001 for V O2 at AT and V O2peak , respectively). The tHb-mass explained 44% of variance in V O2 at AT ( P <0.0001) and 23% in V O2peak ( P =0.001).
Conclusions: In contrast to [Hb], tHb-mass is an important determinant of physical fitness before major elective surgery. Further studies should determine whether low tHb-mass is predictive of poor outcome and whether targeted increases in tHb-mass might thus improve outcome.

Cardiopulmonary reserve as determined by cardiopulmonary exercise testing correlates with length of stay and predicts complications after radical cystectomy.

Tolchard S, Angell J, Pyke M, et al.

BJU Int. 2015;115(4):554-561

OBJECTIVE: To investigate whether poor preoperative cardiopulmonary reserve and comorbid state dictate high-risk status and can predict complications in patients undergoing radical cystectomy (RC). PATIENTS AND METHODS: In all, 105 consecutive patients with transitional cell carcinoma (TCC; stage T1-T3) undergoing robot-assisted (38 patients) or open (67) RC in a single UK centre underwent preoperative cardiopulmonary exercise testing (CPET). Prospective primary outcome variables were all-cause complications and postoperative length of stay (LOS). Binary logistic regression analysis identified potential predictive factor(s) and the predictive accuracy of CPET for all-cause complications was examined using receiver operator characteristic (ROC) curve analysis. Correlations analysis employed Spearman’s rank correlation and group comparison, the Mann-Whitney U-test and Fisher’s exact test. Any relationships were confirmed using the Mantel-Haenszel common odds ratio estimate, Kaplan-Meier analysis and the chi-squared test.

RESULTS: The anaerobic threshold (AT) was negatively (r = -206, P = 0.035), and the ventilatory equivalent for carbon dioxide (VE/VCO(2)) positively (r = 0.324, P = 0.001) correlated with complications and LOS. Logistic regression analysis identified low AT (<11 mL/kg/min), high VE/VC0(2) (>/=33) and hypertension as significant factors, such that, in their presence patients were 5.55-times more likely to have complications at 90 days postoperatively [P = 0.001, 95% confidence interval (CI) 2.2-13.9]. ROC analysis showed a high significance (area under the curve 0.78, 95% CI 0.69-0.87; P < 0.001). In addition, based on CPET criteria >50% of patients presenting for RC had significant heart failure, whereas preoperatively only very few (2%) had this diagnosis. Analysis using the Mann-Whitney test showed that a VE/VCO(2) >/=33 was the most significant determinant of LOS (P = 0.004). Kaplan-Meier analysis showed that patients in this group had an additional median LOS of 4 days (P = 0.008). Finally, patients with an American Society of Anesthesiologists grade of 3 (ASA 3) and those on long-term beta-blocker therapy were found to be at particular risk of myocardial infarction (MI) and death after RC with odds ratios of 4.0 (95% CI 1.05-15.2; P = 0.042) and 6.3 (95% CI 1.60-24.8; P = 0.008).

CONCLUSION: Patients with poor cardiopulmonary reserve and hypertension are at higher risk of postoperative complications and have increased LOS after RC. Heart failure is known to be a significant determinant of perioperative death and is significantly under diagnosed in this patient group.

Effects of persistent Fontan fenestration patency on cardiopulmonary exercise testing variables.

Heal ME, Jackson LB, Atz AM, Butts RJ

Congenit Heart Dis. 2017 Jun 15. doi: 10.1111/chd.12451. [Epub ahead of print]

Cardiopulmonary exercise testing (CPET) aids in clinical assessment of patients
with Fontan circulation. Effects of persistent fenestration on CPET variables
have not been clearly defined. Associations between fenestration and CPET
variables at anaerobic threshold (AT) and peak exercise were explored in the
Pediatric Heart Network Fontan Cross-Sectional Study cohort. Fenestration patency
was associated with a greater decrease in oxygen saturation from rest to peak
exercise (fenestration -4.9 ± 3.8 v. nonfenestration -3 ± 3.5; P < .001).
Physiological dead space at peak exercise was higher in fenestrated v.
nonfenestrated (25.2 ± 16.1 v. 21.4 ± 15.2; P = .03). There was a weak
association between fenestration patency and maximal work and heart rate.
Fenestration patency was also weakly correlated with oxygen pulse, work and
VE/VCO2 at AT. The effect of persistent fenestration on CPET measurements was
minimal in this study, likely due to the cross-sectional design.

Survival after postoperative morbidity: a longitudinal observational cohort

Moonesinghe SR, Harris S, Mythen MG, et al.

Br J Anaesth. 2014;113(6):977-984

BACKGROUND: Previous studies have suggested that there may be long-term harm associated with postoperative complications. Uncertainty exists however, because of the need for risk adjustment and inconsistent definitions of postoperative morbidity.
METHODS: We did a longitudinal observational cohort study of patients undergoing major surgery. Case-mix adjustment was applied and morbidity was recorded using a validated outcome measure. Cox proportional hazards modelling using time-dependent covariates was used to measure the independent relationship between prolonged postoperative morbidity and longer term survival.
RESULTS: Data were analysed for 1362 patients. The median length of stay was 9 days and the median follow-up time was 6.5 yr. Independent of perioperative risk, postoperative neurological morbidity (prevalence 2.9%) was associated with a relative hazard for long-term mortality of 2.00 [P=0.001; 95% confidence interval (CI) 1.32-3.04]. Prolonged postoperative morbidity (prevalence 15.6%) conferred a relative hazard for death in the first 12 months after surgery of 3.51 (P<0.001; 95% CI 2.28-5.42) and for the next 2 yr of 2.44 (P<0.001; 95% CI 1.62-3.65), returning to baseline thereafter.
CONCLUSIONS: Prolonged morbidity after surgery is associated with a risk of premature death for a longer duration than perhaps is commonly thought; however, this risk falls with time. We suggest that prolonged postoperative morbidity measured in this way may be a valid indicator of the quality of surgical healthcare. Our findings reinforce the importance of research and quality improvement initiatives aimed at reducing the duration and severity of postoperative complications.

The Preoperative Assessment and Optimization of Patients Undergoing Major Urological Surgery

Cui HW, Turney BW, Griffiths J.

Curr Urol Rep. 2017 Jul;18(7):54. doi: 10.1007/s11934-017-0701-z

PURPOSE OF REVIEW: Improving patient outcomes from major urological surgery
requires not only advancement in surgical technique and technology, but also the
practice of patient-centered, multidisciplinary, and integrated medical care of
these patients from the moment of contemplation of surgery until full recovery.
This review examines the evidence for recent developments in preoperative
assessment and optimization that is of relevance to major urological surgery.
RECENT FINDINGS: Current perioperative medicine recommendations aim to improve
the short-term safety and long-term effectiveness of surgical treatments by the
delivery of multidisciplinary integrated medical care. New strategies to deliver
this aim include preoperative risk stratification using a frailty index and
cardiopulmonary exercise testing for patients undergoing intra-abdominal surgery
(including radical cystectomy), preoperative management of iron deficiency and
anemia, and preoperative exercise intervention. Proof of the utility and validity
for improving surgical outcomes through advances in preoperative care is still
evolving. Evidence-based developments in this field are likely to benefit
patients undergoing major urological surgery, but further research targeted at
high-risk patients undergoing specific urological operations is required.

Open label study of ambrisentan in patients with exercise pulmonary hypertension

Segrera SA, Lawler L, Opotowsky AR, Systrom D, Waxman AB.

Pulm Circ. 2017 Apr-Jun;7(2):531-538. doi: 10.1177/2045893217709024. Epub 2017
May 12.

A growing body of evidence suggests that exercise pulmonary hypertension (ePH) is
an early form of pulmonary arterial hypertension (PAH). Identifying the disease
at an early, potentially more responsive phase, and initiating treatment may
improve functional status and prevent progression to severe forms of PAH.
This was a single-center, open-label six-month treatment trial to evaluate the effect
of ambrisentan on pulmonary hemodynamics and exercise capacity in ePH utilizing
invasive cardiopulmonary exercise testing (iCPET). After six months of treatment
with ambrisentan, patients repeated iCPET; exercise capacity, symptoms, and
pulmonary hemodynamics were reassessed. Twenty-two of 30 patients completed the
treatment phase and repeat iCPET. After six months of treatment there was a
significant decline in peak exercise mPAP (-5.2 ± 5.6 mmHg, P = 0.001), TPG
(-7.1 ± 8.0 mmHg, P = 0.001), PVR (-0.9 ± 0.7 Woods units, P = 0.0002), and
Ca-vO2 (-1.8 ± 2.3 mL/dL, P = 0.0002), with significant increases in peak PCWP
(+2.9 ± 5.6 mmHg, P = 0.02), PVC (+0.8 ± 1.4 mL/mmHg, P = 0.03), and CO
(+2.3 ± 1.4 L/min, P = 0.0001). A trend toward increased VO2max (+4.4 ± 2.6%
predicted, P = 0.07) was observed. In addition, there were improvements in 6MWD
and WHO FC after 24 weeks.
Our findings suggest that treatment of ePH with
ambrisentan results in improved pulmonary hemodynamics and functional status over
a six-month period. Treatment of ePH may prevent the progression of vascular
remodeling and development of established PAH.

Exercise Testing, Supplemental Oxygen and Hypoxia.

Ward SA; Human Bio-Energetics Research Centre, Crickhowell, United Kingdom of Great Britain and Northern Ireland ; saward@dsl.pipex.com.
Grocott MP; University of Southampton, 7423, Anaesthesia and Critical Care Research Unit, Faculty of Medicine, Southampton, Hampshire, United Kingdom of Great Britain and Northern Ireland ; m.grocott@soton.ac.uk.
Levett DZ; University of Southampton, Anaesthesia and Critical Care Research Unit, Faculty of Medicine, Southampton, Hampshire, United Kingdom of Great Britain and Northern Ireland ; d.levett@soton.ac.uk.

Annals Of The American Thoracic Society [Ann Am Thorac Soc] 2017 Jun 07. Date of Electronic Publication: 2017 Jun 07.

Cardiopulmonary exercise testing (CPET) in hyperoxia and hypoxia has several applications, stemming from characterization of abnormal physiological response profiles associated with exercise intolerance. As altered oxygenation can impact on the performance of gas-concentration and flow sensors and pulmonary gas exchange algorithms, integrated CPET system function requires validation under these conditions. Also, as oxygenation status can influence peak O2 uptake, care should be taken in the selection of work-rate incrementation rates when CPET performance is to be compared with sea-level. CPET has been used to evaluate the effects of supplemental O2 on exercise intolerance in chronic obstructive pulmonary disease, interstitial pulmonary fibrosis and cystic fibrosis at sea-level. However, identification of those CPET indices likely to be predictive of supplemental O2 outcomes for exercise tolerance at altitude in such patients is lacking. CPET performance with supplemental O2 in respiratory patients residing at high altitudes is poorly studied. Finally, CPET has the potential to give physiological and clinical information about acute and chronic mountain sickness, high-altitude pulmonary edema, and high-altitude cerebral edema. It can translate high-altitude acclimatization and adaptive processes in healthy individuals into intensive care medical practice.