Experimental Study On The Quantification Of Valsalva Maneuver Using Disposable Medical Syringes

Background:The Valsalva maneuver is currently used in the Cardiovascular Department for the auxiliary diagnosis of the right-to-left shunt of patent foramen ovale in congenital heart disease and the treatment of hemodynamically stable supraventricular tachycardia.Studies have shown that Valsalva exhalation produces the equivalent of40 mmHg intrathoracic pressure obtained the maximum vagal tone response.However,the actual operation process of Valsalva maneuver at clinic was not standardized and can not achieve the standardization and quantification of Valsalva movement.Purpose:In this study,daily used disposable medical plastic syringes were used to test the pressure range in which the inner core of different syringes was smoothly moved,in an attempt to find one or several syringes of ideal capacity to produce a smooth movement of the inner core.The tension is just about 40 mmHg,so it can be used to assist in the quantification of Valsalva maneuver,thus simplifying and standardizing the operation of the currently clinically unregulated Valvalsa maneuver,and better guiding the clinical application of Valsalva maneuver.Method:In this study,the spring gauge sphygmomanometer and the desktop mercury column sphygmomanometer,which are used to measure blood pressure in clinical practice,have been partially modified.Remove the cuff portion of the spring-type sphygmomanometer.After the cuff is removed,the broken end of a 15 cm long rubber tube is connected to the syringe to be tested through a medical three-way switching valve to ensure the airway seal of the device passage after the modification.Similarly,remove the cuff portion of the benchtop mercury sphygmomanometer and connect thebroken ends of the two 15 cm rubber tubes with the cuff removed by two three-way switching valves.The three-way switching valve is connected to the syringe to be tested,and the other end of the rubber tube is a rubber pressurized balloon used for pressurizing the syringe to be tested.The 1 mL flat mouth,2 mL flat mouth,5 mL flat mouth,5 mL spiral mouth,10 mL flat mouth,20 mL flat mouth,20 mL spiral mouth and 60 mL flat mouth disposable medical plastic syringes manufactured by Shandong Xinhua Ande Medical Co.,Ltd.were selected.Each syringe to be tested was connected with the modified spring gauge and table mercury column sphygmomanometers through a three-way transfer valve and a 15 cm long rubber tube.The author used the balloon of the sphygmomanometer to inflate the sealed device to move the inner core of the syringe to be measured.The pressure ranges produced by the inner core of the syringe with different volumes starts to move and smoothly moves for 15 seconds were measured by the blood pressure meters.The experiment was divided into two parts including the screening of different volume syringes and the validation of the screened syringes.First,20 samples of 1mL,2 mL,5 mL,10 mL,20 mL,60 mL flat-mouth syringes and 10 mL and 20 mL spiral syringes were randomly selected in order to screen out the ideal syringes that can produce a pressure range equivalent to 30-50 mmHg.Then,50 syringes of the ideal capacity that have been screened were randomly selected from different packages,and the results of the foregoing screening tests were verified.At the time of testing,each syringe to be tested was first opened in the original package,and the pressure range in which the inner core began to smoothly move was measured without changing the inner core position of the syringe.The inner core of the syringe was then manually moved to the 1/4,1/2 and 3/4 positions of the length of the syringe barrel,respectively,and the pressure range at which the inner core began to smoothly movement was measured again.Finally,the inner core of the syringe was moved back to the original position(0/0 position),and the pressure range in which the inner core began to smoothly move was repeated.The pressure range was first measured using a modified spring-type gauge sphygmomanometer and then replaced with a modifiedbenchtop mercury sphygmomanometer for repeated measurements.Each syringe was tested five times at which the inner core of the tested spring was in a new package,and at the positions of 1/4,1/2,3/4,and 0/0 of the spring barrel,respectively,and,there was 5 minutes apart from each test.The measurement was started as soon as the syringe core was manually moved to the predetermined position of the test.Results:Screening results: Almost all the tested syringes were “stuck” when they were opened in a new package without moving the original position of the inner cores,that is,the pressure of >300 mmHg was required to move the inner cores.Once the inner cores of the syringes were moved away from the initial position,the required pressures for movement were significantly reduced.After the balloon was pressurized to move the inner core,the inner cores did not eject out from the syringe barrels at all the test positions.The results of the spring gauge and mercury column sphygmomanometer were averaged,we obtained the ratio of pressure between 30-50 mmHg at 1/4,1/2,3/4,0/0 positions of 5 mL spiral syringes was 90%,80%,50% and80%,respectively.The proportion of 20 mL screw syringes was 95%,100%,90%,and 85%,respectively.The proportion of 60 mL flat-mouth syringes was 60%,90%,90%,and 90%,respectively.At the same time,the average or median pressures of the above syringes measured at different positions using a spring gauge and a mercury sphygmomanometer were almost between 30 mmHg and 50 mmHg.Therefore,5 mL screw port,20 mL screw port,and 60 mL flat-mouth syringes were selected to increase the sample size for further verification.Verification results: All the tested syringes are “stuck” when they were opened in a new package and did not move the original position of the core,that is,the pressure of >300 mmHg was required to move the inner cores.After the inner cores began to move,there was no inner core ejecting out from the syringe barrel at all the test positions.The measurement was repeated by the spring-type and mercury-type sphygmomanometers,respectively,and the results were showed as following: The 5mL screw-mouth syringes were “stuck” after being opened,and the pressure values at3/4 position were 38.0(34.0-42.5)mmHg and 37.0±4.8 mmHg,respectively.Thepressures were 40.0(37.5-44.0)mmHg and 41.4±6.0 mmHg at the 1/2 position,48.9±10.0 mmHg and 46.7±8.0 mmHg at the 3/4 position,and 36.8±3.3 mmHg and38.0(34.0-40.0))mmHg at the 0/0 position,respectively.100% 5 mL screw syringes produced the pressure range(maximum and minimum)at the 0/0,1/4,and 1/2positions within 30-50 mmHg.Conclusion:This study confirmed that the 5 mL screw port syringes produced by Shandong Xinhua Ande Medical Co.,Ltd.can produce a stable,ideal 30-50 mmHg pressure when the inner core was at 1/4 position,1/2 position,and return to 0 position.Therefore,it can be used to assist in the quantification of Valsalva maneuver to achieve the recommended standard intrathoracic pressure in order to obtain the optimal efficiency of Valsalva maneuver.