JP3670202B2 - Method for measuring patient weight and patient bed for weight measurement - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method and an apparatus that enable weight measurement without placing a burden on a sleeping patient.
[0002]
[Prior art]
Advances in medical technology for critically ill patients have been remarkable, and along with this, many state-of-the-art devices necessary for circulatory breathing management have been used in the intensive care unit, and treatment based on real-time measurement results has been performed. As a measurement result, not only blood pressure, heart rate and body temperature but also blood oxygen saturation and cardiac output are displayed one by one. In particular, in patients with heart failure and renal failure, etc., whose water balance is not self-regulating and has a narrow safety range, the current excess or deficiency of water in the body is evaluated through careful observation and diagnosis, and future treatment strategies are determined. Is done.
[0003]
Treatment strategies are determined using these techniques, but the most important decision is the water dose. The amount of water administered and the amount of excreted water such as urine are calculated in units of 1 ml and used as basic data for water balance evaluation. Although the visible water can be calculated relatively easily, it is practically difficult to grasp the amount of invisible water lost due to moisture, sweat, and insensitive excretion during breathing. As a result, the accuracy of the calculated water balance is not high.
[0004]
[Problems to be solved by the invention]
By the way, the most convenient and reliable information for estimating the water balance is the body weight, and the body weight change in the acute phase is used as an important index representing the body water content. However, in the intensive care unit, it is difficult to move a patient to which various tubes are connected for drug administration and the like, and therefore, weight measurement is rarely performed.
[0005]
There are also known methods of measuring weight by placing four scales under each of the four legs of the bed, but placing or removing the scales with the patient on the bed when moving to a CT examination or operating room This is not practical because it is difficult to do. There is a device that puts a sheet on the back of the patient and raises the four corners of the sheet in a hammock to measure the weight, but lifting the patient and laying the sheet is a heavy labor, and the patient may be in a dangerous situation. For this reason, it is desired to develop a bed that can easily measure the weight without moving the patient at all.
[0006]
[Means for Solving the Problems]
The present invention has been devised to meet such demands, and utilizes the difference in force required to lift the patient bed before and after the mattress is moved horizontally, so that weight measurement can be performed without having to move the patient. The purpose is to make it possible.
[0007]
In order to achieve the object, the weight measurement method of the present invention lifts the left or right end of the patient bed while the patient is laid down, measures the force F ₁ required for lifting, and then lays the mattress while the patient is laid down. After horizontally moving in the width direction of the patient bed, the same side of the patient bed is lifted with the patient lying down, the force F ₂ required for lifting is measured, and the patient weight f ₄ is calculated according to the following equation: To do.
[0008]
f ₄ = ΔF × L ₂ / ΔL−f ₃
However, ΔF: difference between forces F ₁ and F ₂ required to lift the patient bed (F ₂ −F ₁ )
L ₂ : Mattress width ΔL: Horizontal movement distance of mattress f ₃ : Total weight of mattress and its moving mechanism The patient bed used for this weight measurement has a slide moving plate that horizontally moves the mattress in the width direction of the patient bed. It has been incorporated.
[0009]
Embodiment
In the present invention, for example, as shown in FIG. 1, a slide moving plate 2 is incorporated in a patient bed 1. A rack gear 5 that meshes with a rack gear 3 built in the width direction of the patient bed 1 via a gear 4 is fixed to the lower surface of the slide moving plate 2. When the gear 4 is rotated by operating the crank 6, the slide moving plate 2 moves horizontally in the width direction of the patient bed 1. The moving distance of the slide moving plate 2 is set so that the mattress superimposed thereon can move about 30 cm in the horizontal direction while the patient is lying.
[0010]
The weight of the patient is obtained as follows from the force required at that time by lifting the right or left end of the patient bed 1 before and after moving the mattress.
First, the mattress is moved to the left end while the patient is laid down, and the right end of the patient bed 1 is lifted. Patient weight, slide moving plate 2, mattress weight (hereinafter referred to as moving body weight) is f ₁ , patient bed 1 weight excluding moving body weight f ₁ is f ₂ , patient from left end (fulcrum P) of patient bed 1 When the distance L ₁ to the center of gravity and the width of the patient bed 1 (distance from the fulcrum P to the right end) is L ₂ , the force F ₁ required to lift the patient bed 1, the moving body weight f _1, and the weight of the patient bed 1 relationship following Equation (1) between f ₂ is established (Fig. 2a).
_{F 1 × L 2 = f 1} × L 1 + f 2 × L 2/2 ···· (1)
[0011]
Next, the entire mattress is moved rightward while the patient is laid down, and then the right end of the patient bed 1 is similarly lifted. When the force F ₂ required for lifting at this time is the moving distance ΔL of the mattress, the relationship of the following equation (2) is established between the moving body weight f ₁ and the weight f ₂ of the patient bed 1 ( FIG. 2b).
_{F 2 × L 2 = f 1} × (L 1 + ΔL) + f 2 × L 2/2 ···· (2)
[0012]
By subtracting equation (1) from equation (2), the following equation (3) is obtained.
(F ₂ −F ₁ ) × L ₂ = f ₁ × ΔL (3)
That is, the difference ΔF between the force F ₂ required to lift the patient bed 1 when the mattress is at the right end and the force F ₂ required to lift the patient bed 1 when the mat is at the left end is the moving body weight f _1. And the movement distance ΔL of the mattress.
[0013]
Equation (3) can be rewritten as follows.
f ₁ = ΔF × L ₂ / ΔL (4)
The moving body weight f ₁ is the total weight of the patient, the mattress and the slide moving plate 2. Among these, the mattress and the slide moving plate 2 are fixed values with respect to the patient bed 1. Therefore, the patient weight f ₄ is obtained by subtracting the total weight f ₃ of the mattress and the slide moving plate 2 from the moving body weight f ₁ calculated by Expression (4) (Expression 5).
f ₄ = f ₁ −f ₃ (5)
[0014]
According to this method, the patient weight f is obtained by measuring the forces F ₁ and F ₂ required to lift the patient bed 1 before and after the movement by horizontally moving the mattress with the patient lying down without having to move the patient on the mattress. ₄ can be known. This greatly reduces the burden on the patient. In addition, since the forces F ₁ and F ₂ can be obtained by weight measurement at the moment when the patient bed 1 is lifted, weight measurement is facilitated. In this regard, normal weight measurement requires that the patient and the mattress be lifted high with the same force as the weight, so that not only a large lift needs to be placed around the patient bed 1 but also a person who wants to measure patient weight. It becomes a big burden for.
[0015]
【The invention's effect】
As described above, in the present invention, the mattress is horizontally moved in the width direction of the patient bed while the patient is laid down, and the weight of the patient is measured from the difference in force required to lift the patient bed before and after the movement. Yes. When this method is used, the weight can be measured while the patient is laid down without having to move the patient, so the burden on the patient is greatly reduced. For the weight measurer, the work load is reduced because the weight measurement at the moment of lifting the patient bed to a slight height is sufficient.
[Brief description of the drawings]
FIG. 1 is a patient bed in which a mattress can be moved horizontally. FIG. 2 is a principle diagram for explaining weight measurement according to the present invention.
1: patient bed 2: sliding plate 3, 5: rack 4: gear 6: Crank f _1: moving the weight f _2: the weight of the patient bed L _1: distance from the fulcrum P to the patient center of gravity L _2: the patient's bed Width ΔL: Mattress moving distance F ₁ : Force required to lift the patient bed 1 when the mattress is at the left end F ₂ : Force required to lift the patient bed 1 when the mattress is at the right end

Claims (2)

Lift the left or right end of the patient bed with the patient lying down, measure the force F ₁ required for lifting, and then move the mattress horizontally in the width direction of the patient bed with the patient lying down, then lay the patient down A method for measuring patient weight, characterized in that the same side of the patient bed is lifted, the force F ₂ required for lifting is measured, and the patient weight f ₄ is calculated according to the following equation:
f ₄ = ΔF × L ₂ / ΔL−f ₃
However, ΔF: difference between forces F ₁ and F ₂ required to lift the patient bed (F ₂ −F ₁ )
L ₂ : Mattress width ΔL: Mattress horizontal movement distance f ₃ : Total weight of mattress and its moving mechanism The slide moving plate that moves the mattress horizontally in the width direction of the patient bed is incorporated, and the patient weight is measured from the difference in force required when lifting one side of the patient bed when the mattress is moved to the left and right ends. A patient bed for weight measurement, characterized in that:

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