In treating hospitalized patients the body weight and its fluctuations is often of great importance, particularly in cases of actual or impending electrolyte and water imbalance. This determination supplements laboratory data, and makes its interpretation easier, more accurate, more relevant and more meaningful. It provides the clinical observer with objective information which may prove vital for proper and successful treatment of the patient.
In some cases, it is necessary that bedridden patients remain in their lying position. To weigh such patients the scale must be constructed so that the patient can be transferred from the bed onto the scale and weighed while he remains inclined. Such scales generally provide a support structure, usually freely movable over the ground by mounting the structure on casters and a weighing mechanism including a weigh-board carried for supporting the patient in his inclined position during the weighing operation. The weigh-board is sufficiently elevated above ground so that it can be moved over the patient's bed. The support structure includes a base disposed below the weigh-board which is moved beneath the bed while the weigh-board is positioned over the bed. To facilitate the storage of the scale while not in use the weigh-board is normally attached to the weighing mechanism so that it can be placed into an upright storage position. A scale of this type is disclosed in U.S. Pat. No. 3,032,131.
There are other prior art scales for weighing patients in their horizontal position which structurally differ from the one disclosed in the referenced patent. However, all scales have the general characteristic of providing a horizontal weigh-board, a movable support frame over the bed for receiving the patient while providing a sturdy and stable support for the weigh-board.
Prior art scales for weighing patients in their horizontal position generally enable accurate measurements and they are relatively convenient for transferring the patient from the bed to the scale and back. However, they have a number of practical deficiencies which can render such scales cumbersome to handle and which may impair their accuracy unless the attendant carefully isolates the scale, and particularly the components of the weighing mechanism, from coming into contact with objects such as the side of the patient's bed, for example. If such contact does occur the measured weight is of course inaccurate. This is particularly serious because such inaccuracies cannot be detected after the measurement has been taken and the scales provide no means of warning the attendant that the weight he measures is inaccurate because the weighing mechanism is in contact with a foreign object, e.g., the bed.
In addition, prior art scales of the type under consideration have certain features which make them cumbersome to operate. For example, the weigh-board is normally pivotally mounted to a portion of the weighing mechanism so that it can be moved between an operative, horizontal position and a vertical storage position. To prevent the accidental movement of the board from one or the other position, it must be locked.
Complicated locking arrangements for retaining the board in its upright storage position required careful operation of the locking mechanism on the part of the attendant. It was frequently necessary that the attendant walk around the scale to the point at which the lock can be applied. This is both cumbersome and time-consuming. An inattentive or careless attendant may forego the locking of the board altogether. While unlocked, however, the board may be accidentally tipped and pivoted into a horizontal position which is undesirable at least and which can injure bystanders or cause standing objects to be knocked down and damaged.
Accordingly, prior art scales for weighing bedridden patients in their horizontal position, while they were adequate when properly operated, had several features which could compromise their accuracy and/or their safety.