Hypohydration and Cardiorespiratory Function
Clinical Observational Study of the Effect of Hypohydration Upon Cardiorespiratory Function
Major non-cardiac surgery has a high degree of morbidity and mortality. Recently, measurement of a patient's preoperative cardiorespiratory reserve, performed non-invasively by cardiopulmonary exercise testing, has been shown to be predictive of outcome following non-cardiac surgery. All patients prior to major surgery are starved for a minimum of 6 hours and often longer prior to major elective surgery. It has been shown that elite athletes who are hypohydrated have reduced exercise capacity and lower cardiorespiratory function. These results are further exaggerated in "non-trained" individuals. Therefore, the starvation policy prior to surgery may have a deleterious effect on outcome after surgery.
4.2 AIMS This is a pilot study of health volunteers to assess the role of carbohydrate (CHO) (preload) and carbohydrate-protein (CHO-P) (Highfive energy source 1 in 4) in improving aerobic capacity after a period of fasting mimicking the current starvation policy prior to surgery. Both of these have similar calorific value and only differ in the amount of carbohydrate and protein supplementation.
調査の概要
詳細な説明
2 OUTLINE OF STUDY METHODOLOGY (See Appendix D) The methodology of the testing is outlined below:-
STARVATION POLICY The three exercise tests will be undertaken on three separate days but at the same time in the morning to minimise the starvation time and ensure consistency. All patients will be asked not to partake in strenuous exercise 24 hours prior to the test as this could affect hydration and performance status.
Starvation exercise test Participants will be asked to starve from midnight prior to the test. They may have a small glass of water at 6am on the day of the test. This is in line with the current starvation policy at the Freeman Hospital.
CHO loaded test Participants will be asked to drink an isotonic carbohydrate loaded drink (preload) appendix E the night before the test and also two hours prior to the CPX test. This type of clear drink has been shown to be emptied from the stomach within 2 hours and as such can be administered safely on the day of surgery. They again will be asked to starve from midnight prior to the test.
CHO-P loaded test
Participants will be asked to drink an isotonic carbohydrate drink (Highfive energy source 4:1) the night prior to the test and also two hours prior to the CPX test. Again, it has been shown that this type of drink is emptied from the stomach rapidly. They again will be asked to starve from midnight of the test
CARDIOPULMONARY EXERCISE TESTING
Cardiopulmonary exercise measurements are conducted in the consistent environment of the preassessment clinic in Clinic H, Freeman Hospital. CPX equipment includes an electronically braked cycle ergonometer, 12 lead ECG and a metabolic cart. The ECG allows online monitoring of all leads for rate and rhythm, and can measure changes in any S-T segment depression/elevation suggestive of cardiac ischaemia. The metabolic cart has oxygen and carbon dioxide analysers with a response time enabling breath-by-breath measurement. Calibration is ensured before each test. VO2, VCO2, heart rate, minute ventilation, and work rate are displayed continuously throughout the test.
Setting up the CPX test Patients have ECG leads applied before getting on the bike, and are coached on the mouthpiece and communication during the test. They are instructed to give their 'best effort' but to stop if they feel dizzy or faint. The increment in work rate is predetermined using equations for an estimate of expected work capacity, to aim for the test duration to be approximately 6-10 minutes.
CPX Test protocol Initially, 2 - 5 minutes of resting data is performed, ensuring patient comfort, and that the Respiratory Exchange Ratio (RER) falls below 1, indication the patient is not hyperventilating. Next, there is 1-3 minutes of unloaded cycling, followed by a graded increase in incremental workload. The leg speed throughout the test is maintained at 50-60 rpm to ensure constant effort. The patient is given verbal feedback and encouragement throughout the test. The test is stopped by the patient due to fatigue, pain, light headedness, or when they fail to maintain greater than 30 rpm for more than one minute despite encouragement. On completion of the exercise phase of the test, the patient is further monitored during the recovery period until heart rate reaches within 10% of pre-test, and all ST segments have normalised if applicable.
Exercise data processing Results are presented in standard nine-panel format compiled by CPX software. Further analysis for sub maximal parameters related to cardiopulmonary reserve is undertaken by trained personnel
研究の種類
入学 (実際)
段階
- 適用できない
連絡先と場所
研究場所
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Tyne and Wear
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Newcastle upon tyne、Tyne and Wear、イギリス、NE77DN
- Dept of perioperative and critical care medicine, Freeman Hospital
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参加基準
適格基準
就学可能な年齢
健康ボランティアの受け入れ
受講資格のある性別
説明
Inclusion Criteria:
- Aged over 18 years
- Volunteers with capacity to give informed consent
- No underlying medical problems
- Comprehension Of English
Exclusion Criteria:
- Volunteers who lack the ability to consent
- Those unable to exercise
- Those with contraindications to exercise testing (appendix A)
- Diabetics - both insulin and non-insulin dependent diabetics due to the starvation period and carbohydrate load
- Allergy to milk
研究計画
研究はどのように設計されていますか?
デザインの詳細
- 主な目的:基礎科学
- 割り当て:非ランダム化
- 介入モデル:単一グループの割り当て
- マスキング:ダブル
武器と介入
参加者グループ / アーム |
介入・治療 |
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アクティブコンパレータ:Carbohydrate
CHO loaded test:
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Participants will be asked to drink an isotonic carbohydrate loaded drink (preload)night before the test and also two hours prior to the CPX test.
他の名前:
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アクティブコンパレータ:Carbohydrate protein
CHO-P loaded test:
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Participants will be asked to drink an isotonic carbohydrate drink (Highfive energy source 4:1)the night prior to the test and also two hours prior to the CPX test.
他の名前:
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アクティブコンパレータ:Water
Starved as for surgery
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Participants will be asked to starve as per normal clinical requirements for surgery.
They are allowed to drink water upto 2 hours prior to the CPX test
他の名前:
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この研究は何を測定していますか?
主要な結果の測定
結果測定 |
時間枠 |
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1) To determine whether a period of starvation prior to exercise testing adversely affects cardiorespiratory reserve as assessed by cardiopulmonary exercise (CPX) testing
時間枠:14 days
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14 days
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協力者と研究者
捜査官
- 主任研究者:James Prentis, MBBS、Newcastle-upon-Tyne Hospitals NHS Trust
研究記録日
主要日程の研究
研究開始
一次修了 (実際)
研究の完了 (実際)
試験登録日
最初に提出
QC基準を満たした最初の提出物
最初の投稿 (見積もり)
学習記録の更新
投稿された最後の更新 (見積もり)
QC基準を満たした最後の更新が送信されました
最終確認日
詳しくは
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