

ORIGINAL ARTICLE 

Year : 2018  Volume
: 12
 Issue : 1  Page : 2425 


Simple predictor of minute ventilation: HollidaySegar revisited
Priyankar Kumar Datta^{1}, Ajisha Aravindan^{2}, Jayanandan E Sreekumar^{3}, Ajay Singh^{1}, Shambo Guha Roy^{4}
^{1} Department of Anaesthesiology, Pain Medicine and Critical Care, All India Institute of Medical Sciences, New Delhi, India ^{2} Department of Anaesthesiology, Safdarjung Hospital, New Delhi, India ^{3} Department of Anaesthesiology, Sri Ramchandra Medical College, Chennai, Tamil Nadu, India ^{4} Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
Date of Web Publication  9Mar2018 
Correspondence Address: Dr. Priyankar Kumar Datta Department of Anaesthesiology, Pain Medicine and Critical Care, All India Institute of Medical Sciences, Room 5011, Acad Block, New Delhi  110 029 India
Source of Support: None, Conflict of Interest: None  Check 
DOI: 10.4103/aer.AER_158_17
Abstract   
Background: Minute ventilation (MV) and calorific requirement (CR) are both functions of metabolic demand. The HollidaySegar formula is a weightbased tool for predicting CR. This study was performed to derive an equation, based on the HollidaySegar formula, for calculating resting MV from bodyweight (BW), which is applicable for all age groups. Methods: MV for BW (obtained from Radford normogram) was plotted against CR for BW (as per HollidaySegar formula), for BWs ranging from neonates to adults. From the scatter plot thus obtained, bestfit line, with the origin as intercept, was drawn. Linear regression analysis was used to obtain R^{2} coefficient and P value. Results: The plot of MV against CR yields a straight line passing through the origin with a slope = 46.87. R^{2} value is 0.98886, P < 0.001. Conclusion: MV can be easily and reliably estimated for all age groups from the equation: MV (mL/min) = 47 × CR (kcal/h).
Keywords: Body weights and measures, pediatrics, pulmonary ventilation
How to cite this article: Datta PK, Aravindan A, Sreekumar JE, Singh A, Roy SG. Simple predictor of minute ventilation: HollidaySegar revisited. Anesth Essays Res 2018;12:245 
How to cite this URL: Datta PK, Aravindan A, Sreekumar JE, Singh A, Roy SG. Simple predictor of minute ventilation: HollidaySegar revisited. Anesth Essays Res [serial online] 2018 [cited 2018 Mar 21];12:245. Available from: http://www.aeronline.org/text.asp?2018/12/1/24/216041 
Introduction   
Resting minute ventilation (MV) is an important physiological parameter with a multitude of applications in the daytoday practice of anesthesia and critical care. Although we know the normal range of MV for adults and nomograms exist for estimation of MV in individuals of various age groups,^{[1],[2],[3]} there is no fixed formula for deriving the normal value of MV, across all age groups, from any easily measured physical characteristic such as body weight (BW). This is because MV does not follow a strictly linear relation with any such physical characteristic of an individual. If however, we can arrive at an equation that reliably predicts resting MV for all age groups, cardiorespiratory assessment, and ventilator management would be greatly simplified.
Holliday and Segar concluded that the calorific requirement (CR) of an average hospitalized patient, of any age group, can be predicted from BW using the “4:2:1” formula:^{[4]}
 4 kcal/kg/h for the 1^{st} 10 kg
 2 kcal/kg/h for the 2^{nd} 10 kg
 1 kcal/kg/h for the remainder.
We know that both MV and CR are functions of the metabolic demand of the body. CR can be calculated from BW using the HollidaySegar formula. Therefore, this study was performed to find out whether it is possible to derive an equation for calculating resting MV from BW, that is applicable for all age groups.
Materials and Methods   
This study was designed as a mathematical derivational exercise whereby existing instruments for predicting MV and CR were compared to obtain a correlation. As no actual patients were involved in the study, ethical approval was not required.
MV obtained from Radford nomogram^{[1]} was plotted against CR as per the HollidaySegar formula,^{[4]} for BWs ranging from neonates to adults (3, 5, 7, 10, 15, 20, 30, 40, 50, 60, 70, and 80 kg, n = 12). For adults, the MV was taken as the average of the values obtained for males and females from Radford nomogram.
From the scatter plot thus obtained, bestfit line, with the origin as intercept, was drawn. Linear regression analysis was performed to obtain R^{2} coefficient (regression coefficient) using Microsoft Excel 2013 (Microsoft Corporation, Redmond, WA, USA) for Windows. P value for the obtained R^{2} coefficient was calculated using Social Science Statistics (http://www.socscistatistics.com) open access online calculator. The value of P < 0.01 was considered to be statistically significant.
Results   
The chosen BWs for analysis, the MV for each BW derived from Radford nomogram, and the corresponding CR from HollidaySegar formula have been compared [Table 1].  Table 1: Chosen body weights for comparison, corresponding calorific requirement, and minute ventilation
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The plot of each value of MV against the corresponding CR yielded a straight line passing through the origin with a slope = 46.8 [Figure 1]. R^{2} = 0.98968 (P< 0.001).
Discussion   
Mechanical ventilation needs to be controlled to maintain normal oxygen and carbon dioxide tensions in the blood. Existing ventilation guides, such as Radford's nomogram,^{[1]} Nunn's CO_{2} predictor^{[2]} and the Adelaide ventilation guide,^{[3]} are based on experimentally obtained data, and require plotting BW on that particular chart to obtain the corresponding MV. Although these nomograms are very useful for adjusting ventilator settings in children, especially in resource poor settings where endtidal CO_{2} measurement and blood gas analysis may not be readily available, their practical use is limited as the required charts are too complicated to be memorized, and not often at hand.
Our analysis shows that resting MV has a strong corelation with CR, as calculated by HollidaySegar formula, over all ages from birth to adulthood. This is plausible as both are functions of metabolic demand of the body.
Baseline MV can be easily calculated form the equation:
MV (in mL/min) = 47 × CR (in kcal/h as per HollidaySegar formula).
This simple equation gives us a physiological basis for estimating resting MV from BW, without having to rely on a nomogram chart. The value so obtained can be used for initial ventilatory settings in infants, children, as well as adults of all body sizes. It is, however, important to account for changes in the ratio of dead space ventilation to alveolar ventilation during various ventilatory strategies in the ICU or under anesthesia.^{[5]}
As a corollary, normal resting cardiac output (CO) for BW can also be estimated from the same equation as CO nearly equals MV in resting state to maintain a ventilation to perfusion (V:Q) ratio of 1. Further studies may be conducted to validate this.
Conclusion   
This study shows that resting MV can be easily and reliably estimated for all age groups from the equation: MV (mL/min) = 47 × CR (kcal/h).
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References   
1.  Radford EP Jr., Ferris BG Jr., Kriete BC. Clinical use of a nomogram to estimate proper ventilation during artificial respiration. N Engl J Med 1954;251:87784. 
2.  Nunn JF. Prediction of carbon dioxide tension during anaesthesia. Anaesthesia 1960;15:12333. [ PUBMED] 
3.  Kenny S. The Adelaide ventilation guide. Br J Anaesth 1967;39:213. 
4.  Holliday MA, Segar WE. The maintenance need for water in parenteral fluid therapy. Pediatrics 1957;19:82332. 
5.  Puri GD, Singh H, Kaushik S, Jindal SK. Determination of ventilatory minute volumes for normocapnic ventilation under anaesthesia in healthy adults. Natl Med J India 1999;12:611. 
[Figure 1]
[Table 1]
