Clowes GH; Del Guercio LR;

Circulatory response to trauma of surgical operations. Metabolism. 1960;9:67-81. (NOTE THE DATE)

To determine the nature of the normal cardiovascular response of man to surgi­cal operations, thirteen patients making uncomplicated recoveries after thoraco­tomy for pulmonary surgery were studied by measuring cardiac output and arterial and venous pressure before, during and for one week after surgery. Arterial pH, blood gas and electrolytes were analyzed simultaneously. Through­ out the observations, arterial blood pres­sure was more or less constantly main­tained; but during the operation cardiac output fell an average of  33  per  cent with a decrease of  stroke  volume,  and the calculated peripheral arterial resist­ance rose. Venous pressure was elevated in all patients during the  induction of anesthesia and remained so to the end of the operation. Upon awakening and during extubation, the situation was promptly reversed.  Cardiac output rose to 130 per cent of the resting value; peripheral resistance fell below normal; and venous pressure returned to levels below 10 cm. of H₂0 . These changes persisted to the end of the first post­ operative week. Three patients, who recovered satisfactorily after cardiac operations,  followed a similar  pattern of circulatory response. Arterial pH and pCO₂ were main­tained within normal limits in all pa­tients who recovered; however, all showed some degree of arterial oxygen desaturation postoperatively. Metabolic acidosis,  as  indicated   by  an  elevation of lactic acid, took  place  during  and after the operation but returned to pre­-operative values within three days. Sodium fell, on the average, to 129 mEq./L. on the second postoperative day.  Ionized calcium fell to 4.1 mg. per cent on the first day. Potassium remained unchanged. Three patients who recovered from open heart operations responded in the same fashion with a postoperative in­ crease in cardiac output.
Two patients died postoperatively. Both failed to show the normal post­ operative elevation of cardiac output; metabolic acidosis increased until re­spiratory compensation failed, and ar­terial pH fell below 7.3.

Giovanna A; Christian P; Danielle M; Christoph K; Christian M for the BASEL-PMI Investigators

BJA Vol 126 Number 1 Jan 2021 Pg 102-110

Mustafa E; Aytür YK;

Topics in stroke rehabilitation [Top Stroke Rehabil] 2021 May 22, pp. 1-9. Date of Electronic Publication:
2021 May 22.

Background : Assessment for cardiovascular disease (CVD) is important in stroke patients, both being one of the main factors limiting success in stroke rehabilitation and its increased risk in stroke patients. Reduced exercise capacity after stroke decreases patients’ functionality and further increases the risk of CVD. Carefully selected cardiopulmonary exercise testing (CPET) can be safely used to determine the risk of CVD and to prescribe exercise program in stroke rehabilitation.
Objectives : The primary purpose of this study is to determine the most appropriate CPET in patients with stroke. The secondary aim is to determine the relationship between cardiorespiratory fitness and functional status of the patients.
Methods : Two CPETs using treadmill and bicycle ergometer protocols determined with a preliminary study were performed on participants. The main outcome measure was VO _2peak . Patients were also evaluated according to Brunnstrom motor staging, Modified Ashworth Scale, Berg Balance Scale, and Functional Independence Measure. Results : In total, 38 patients reached higher VO _2peak values at treadmill test compared to bicycle test ( p < 0.001). The mean VO ₂ peak reached at treadmill CPET was 62% of the control group where mean VO _2peak reached at bicycle was 76% of the control group. No significant correlation was found between Brunnstrom staging, spasticity, Berg Balance Scale, and VO _2peak .
Discussion : The results of this study indicate that CPET can be performed safely in stroke patients when appropriate protocol was selected and that treadmill was more appropriate to determine cardiorespiratory fitness in this study population.

Douglas N; Melbourne, Australia.Altamimi H; Wang A; Basto J; Smith R; Taylor HE;

Internal medicine journal [Intern Med J] 2021 May 24. Date of Electronic Publication: 2021 May 24.

Background: One metabolic equivalent (MET) is equal to resting oxygen consumption. The average value for one MET in humans is widely quoted as 3.5ml/kg/min. However this value was derived from a single male participant at the end of the nineteenth century and has become canonical. Several small studies have identified varied estimates of one MET from widely varying populations. The ability of a patient to complete 4 METS (or 14mls/kg/min) is considered an indicator of their fitness to proceed to surgery.
Aims: The study aimed to define a typical value of one MET from a real-world patient population, as well as determine factors that influenced the value.
Methods: A database of cardiopulmonary exercise tests (CPET) tests was interrogated to find total of 1847 adult patients who had undergone CPET testing in the previous 10 years. From this database, estimates of oxygen consumption (VO ₂ ) at rest and at the anaerobic threshold and a number of other variables were obtained. The influence of age, body mass index (BMI), sex and the use of beta blockers was tested.
Results: The median resting VO ₂ at rest was 3.6ml/kg/min (IQR 3.0-4.2). Neither sex nor age greater than 65 years nor the use of beta blockers produced a significant difference in resting VO ₂ , while those with a BMI greater than 25 had a significantly lower VO ₂ at rest (3.4ml/kg/min vs 4.0ml/kg/min, p <0.001).
Conclusions: The estimate of 3.6ml/kg/min for resting VO ₂ presented here is consistent with the previous literature, despite this being the first large study of its kind. This estimate can be safely used for pre-operative risk stratification.

Chmelo J, Khaw RA, Sinclair RCF, Navidi M, Phillips AW.

Ann Surg Oncol. 2021 May 26. doi: 10.1245/s10434-021-10136-5. Online ahead of print.

BACKGROUND: Esophagectomy is associated with a high rate of morbidity and mortality. Preoperative cardiopulmonary fitness has been correlated with outcomes of major surgery. Variables derived from cardiopulmonary exercise testing (CPET) have been associated with postoperative outcomes. It is unclear whether preoperative cardiorespiratory fitness of patients undergoing esophagectomy is associated with long-term survival. This study aimed to evaluate whether any of the CPET variables routinely derived from patients with esophageal cancer may aid in predicting long-term survival after esophagectomy.
METHODS: Patients undergoing CPET followed by trans-thoracic esophagectomy for esophageal cancer with curative intent between January 2013 and January 2017 from single high-volume center were retrospectively analyzed. The relationship between predictive co-variables, including CPET variables and survival, was studied with a Cox proportional hazard model. Receiver operation curve (ROC) analysis was performed to find cutoff values for CPET variables predictive of 3-year survival.
RESULTS: The study analyzed 313 patients. The ventilatory equivalent for carbon dioxide (VE/VCO2) at the anerobic threshold was the only CPET variable independently predictive of long-term survival in the multivariable analysis (hazard ratio [HR], 1.049; 95% confidence interval [CI], 1.011-1.088; p = 0.011). Pathologic stages 3 and 4 disease was the other co-variable found to be independently predictive of survival. An ROC analysis of the VE/VCO2 failed to demonstrate a predictive cutoff value of 3-year survival (area under the curve, 0.564; 95% CI, 0.499-0.629; p = 0.056).
CONCLUSIONS: A high VE/VCO2 before esophagectomy for malignant disease is an independent predictor of long-term survival and may be an important variable for clinicians to consider when counseling patients.

Brito LC; Peçanha T; Fecchio RY; Pio-Abreu A; Silva G; Mion-Junior D; Halliwill JR; Forjaz CLM

Blood pressure monitoring [Blood Press Monit] 2021 May 07. Date of Electronic Publication: 2021 May 07.

Heart rate recovery (HRR) is a marker of cardiac autonomic regulation and an independent predictor of mortality. Aerobic-exercise training conducted in the evening (evening training) produces greater improvement in resting cardiac autonomic control in hypertensives than morning training, suggesting it may also result in a faster autonomic restoration postexercise. This study compared the effects of morning training and evening training on HRR in treated hypertensive men. Forty-nine treated hypertensive men were randomly allocated into three groups: morning training, evening training and control. Training was conducted three times/week for 10 weeks. Training groups cycled (45 min, moderate intensity) while control group stretched (30 min). In the initial and final assessments of the study, HRR60s and HRR300s were evaluated during the active recovery (30 W) from cardiopulmonary exercise tests (CPET) conducted in the morning and evening. Between-within ANOVAs were applied (P ≤ 0.05). Only evening training increased HRR60s and HRR300 differently from control after morning CPET (+4 ± 5 and +7 ± 8 bpm, respectively, P < 0.05) and only evening training increased HRR300s differently from morning training and control after evening CPET (+8 ± 6 bpm, P < 0.05). Evening training improves HRR in treated hypertensive men, suggesting that this time of day is better for eliciting cardiac autonomic improvements via aerobic training in hypertensives.

Watanabe T; Murase N; Kime R; Kurosawa Y; Fuse S; Hamaoka T;

Advances in experimental medicine and biology [Adv Exp Med Biol] 2021; Vol. 1269, pp. 101-105.

The primary symptom in patients with chronic heart failure (CHF) is exercise intolerance. Previous studies have reported that reduced exercise tolerance in CHF can be explained not only by cardiac output (a central factor) but also by reduced skeletal muscle aerobic capacity (a peripheral factor). Although exercise training in CHF improves exercise tolerance, few studies have evaluated the effects of exercise training on each specific central and peripheral factor in CHF. The aim of this study was to investigate the central and peripheral aerobic functions in CHF and the effects of exercise training in CHF on cardiac output and skeletal muscle deoxygenation during exercise. We assessed peak oxygen uptake (VO ₂ ) during cardiopulmonary exercise testing, peak cardiac output (CO) using noninvasive hemodynamic monitoring, and muscle oxygen saturation (SmO ₂ ) using near-infrared spectroscopy (NIRS). Patients with CHF were trained for 12 weeks and performed ramp cycling exercise until exhaustion before and after the exercise training. Peak VO ₂ , peak CO, and SmO ₂ changes from rest to peak exercise (ΔSmO ₂ ) were significantly lower in CHF than those in healthy subjects. As a result of exercise training, peak oxygen uptake in patients with CHF was improved and positively associated with change in ΔSmO ₂ . In contrast, there was no change in peak cardiac output. The results of this study indicate that both cardiac and skeletal muscle functions in patients with CHF were lower than those in healthy subjects. Further, the results suggest that the improvement of exercise capacity in patients with CHF by exercise training was related to the improved utilization of oxygen (a peripheral factor) in skeletal muscle.

McNeill JN; Lau ES; Zern EK; Nayor M; Malhotra R; Liu EE; Bhat RR; Brooks LC; Farrell R; Sbarbaro JA;
Schoenike MW; Medoff BD; Lewis GD; Ho JE;

Respiratory medicine [Respir Med] 2021 Apr 30; Vol. 183, pp. 106434. Date of Electronic Publication: 2021 Apr 30.

Background: Obesity has multifactorial effects on lung function and exercise capacity. The contributions of obesity-related inflammatory pathways to alterations in lung function remain unclear.
Research Question: To examine the association of obesity-related inflammatory pathways with pulmonary function, exercise capacity, and pulmonary-specific contributors to exercise intolerance.
Method: We examined 695 patients who underwent cardiopulmonary exercise testing (CPET) with invasive hemodynamic monitoring at Massachusetts General Hospital between December 2006-June 2017. We investigated the association of adiponectin, leptin, resistin, IL-6, CRP, and insulin resistance (HOMA-IR) with pulmonary function and exercise parameters using multivariable linear regression.
Results: Obesity-related inflammatory pathways were associated with worse lung function. Specifically, higher CRP, IL-6, and HOMA-IR were associated with lower percent predicted FEV ₁ and FVC with a preserved FEV ₁ /FVC ratio suggesting a restrictive physiology pattern (P ≤ 0.001 for all). For example, a 1-SD higher natural-logged CRP level was associated with a nearly 5% lower percent predicted FEV ₁ and FVC (beta -4.8, s.e. 0.9 for FEV1; beta -4.9, s.e. 0.8 for FVC; P < 0.0001 for both). Obesity-related inflammatory pathways were associated with worse pulmonary vascular distensibility (adiponectin, IL-6, and CRP, P < 0.05 for all), as well as lower pulmonary artery compliance (IL-6 and CRP, P ≤ 0.01 for both).
Interpretation: Our findings highlight the importance of obesity-related inflammatory pathways including inflammation and insulin resistance on pulmonary spirometry and pulmonary vascular function. Specifically, systemic inflammation as ascertained by CRP, IL-6 and insulin resistance are associated with restrictive pulmonary physiology independent of BMI. In addition, inflammatory markers were associated with lower exercise capacity and pulmonary vascular dysfunction.

Mihalick VL; Canada JM; Arena R; Abbate A; Kirkman DL;

Progress in cardiovascular diseases [Prog Cardiovasc Dis] 2021 May 06.
Date of Electronic Publication: 2021 May 06.

The outbreak of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has presented a global public health emergency. Although predominantly a pandemic of acute respiratory disease, corona virus infectious disease-19 (COVID-19) results in multi-organ damage that impairs cardiopulmonary (CP) function and reduces cardiorespiratory fitness. Superimposed on the CP consequences of COVID-19 is a marked reduction in physical activity that exacerbates CP disease (CPD) risk. CP exercise testing (CPET) is routinely used in clinical practice to diagnose CPD and assess prognosis; assess cardiovascular safety for rehabilitation; and delineate the physiological contributors to exercise intolerance and exertional fatigue. As such, CPET plays an important role in clinical assessments of convalescent COVID-19 patients as well as research aimed at understanding the long-term health effects of SARS-CoV-2 infection. However, due to the ventilatory expired gas analysis involved with CPET, the procedure is considered an aerosol generating procedure. Therefore, extra precautions should be taken by health care providers and exercise physiologists performing these tests. This paper provides recommendations for CPET testing during the COVID-19 pandemic. These recommendations include indications for CPET; pre-screening assessments; precautions required for testing; and suggested decontamination protocols. These safety recommendations are aimed at preventing SARS-CoV-2 transmission during CPET.

Arena R; Myers J; Kaminsky LA

Journal of cardiopulmonary rehabilitation and prevention [J Cardiopulm Rehabil Prev] 2021 May 11. Date of Electronic Publication: 2021 May 11.

No abstract available