Effects of hypertonic saline (7.5%) on extracellular fluid volumes in healthy volunteers

Abstract

SummaryWe developed a screening questionnaire to be used by nurses to decide which patients should see an anaesthetist for further evaluation before the day of surgery. Our objective was to measure the accuracy of responses to the questionnaire. Agreement between questionnaire responses and the anaesthetist's assessment was assessed. For questions with a prevalence of 5 to 95%, the Kappa coefficient was used; percentage agreement was used for all other questions. Criterion validity was excellent ⁄ good for all questions with a prevalence between 5 and 95%, except for the question 'Do you have kidney disease?' For questions with prevalence < 5%, all demonstrated adequate criterion validity except the questions 'Has anyone in your family had a problem following an anaesthetic?' and 'If you have been put to sleep for an operation were there any anaesthetic problems?' Therefore, it is reasonable for nurses to use this questionnaire to determine which patients an anaesthetist should see before the day of surgery.Keywords Anaesthesia; pre-operative, assessment, questionnaire. Recent advances in anaesthetic and surgical practice have facilitated the growth of 'fast track' surgery [1, 2]. Careful outpatient assessment is fundamental to the success of this type of surgery and the Association of Anaesthetists of Great Britain and Ireland now recommends assessment at a pre-operative assessment (POA) clinic [3].The provision of a pre-operative screening and assessment service at POA clinics supplies background information about patient's general medical status and fitness for anaesthesia. POA clinics improve patient care by allowing careful pre-operative evaluation and optimisation of coexisting disease [4], reduce costs [5, 6], improve efficiency [7], and lower surgical cancellation rates [8, 9].In POA clinics, nurses increasingly carry out preoperative screening [10]. Although they are not qualified to decide if a patient is fit for anaesthesia, they play a valuable role in identifying patients who are at risk and require further evaluation and optimisation before the day of surgery [11]. Nurses screen patients for risk factors for fitness for anaesthesia and surgery using questionnaires [12]. These can be self-administered by the patient [9], or used during structured interviews [13], or computer programs [14]. Although many locally developed questionnaires exist, few have been formally assessed.We have developed a multi-tiered screening questionnaire to be used by nurses to decide which patients should be seen at a POA clinic by an anaesthetist for further evaluation and optimisation. Using Delphi consensus methods, we have already evaluated content validity for each question [15] to ensure that the questions are relevant to concept being measured.Our objective was to perform item analysis of the screening questionnaire and measure criterion validity [16], that is, is it a true measure of what it is designed to measure?By testing individual questions beyond basic content validity, we were able to put them together in a...

Acid base and electrolyte changes after hypertonic saline (7.5%) infusion: A randomized controlled clinical trial

“…A similar increase in plasma volume after infusion of 4 ml/kg 7.5% NaCl has previously been measured using dilution of 125-iodine-labelled human albumin in postmenopausal female volunteers [24]. We observed an increase in venous carbon dioxide tension (PCO 2 ) after hypertonic saline infusion.…”

Hypertonic Saline- Hydroxyethyl Starch In Trauma Resuscitation

“…Osmotic Effects HS increases intravascular volume by drawing intracellular water into the intravascular and interstitial spaces (6)(7)(8)(9). Under physiological conditions the balance of Starling's forces within the microcirculation causes a small net efflux of water from the intravascular space.…”

'Physiological' 0.9% Saline In The Fluid Resuscitation Of Trauma

“…Hypertonic saline may cause advantageous changes in the microcirculatory and immune responses to trauma and hypovolaemia (27,29). It increases intravascular volume by pulling intracellular water into the intravascular and interstitial spaces by osmosis (30,31) and improves haemodynamic parameters in hypovolaemia in volumes at which 0.9% saline is ineffective (32). Hypertonic saline solutions cause an increased arterial blood pressure in resuscitation at volumes as low as 4ml/kg.…”