阅读说明：本技术 用于超声血管密封的方法和系统 (method and system for ultrasonic vascular sealing ) 是由 K·E·古德曼 于 2019-05-31 设计创作，主要内容包括：本发明提供了一种方法,所述方法包括：向换能器提供电能以用于密封血管,其中所述电能的频率在超声波范围内；在末端执行器抓握所述血管时,控制所述电能以实现联接到所述换能器的所述末端执行器的预定速度；当所述末端执行器实现所述预定速度时,感测所述电能的参数；基于所述所感测的参数计算所述电能的功率并基于所述功率估计所述血管的尺寸范围；以及控制所述电能来实现目标速度以密封所述血管,所述目标速度是基于所述血管的所述估计尺寸范围来确定的。(The invention provides a method, comprising: providing electrical energy to a transducer for sealing a blood vessel, wherein the electrical energy has a frequency in the ultrasonic range; controlling the electrical energy to achieve a predetermined velocity of the end effector coupled to the transducer while the end effector grasps the blood vessel; sensing a parameter of the electrical energy when the end effector achieves the predetermined speed; calculating a power of the electrical energy based on the sensed parameter and estimating a size range of the blood vessel based on the power; and controlling the electrical energy to achieve a target speed to seal the blood vessel, the target speed determined based on the estimated size range of the blood vessel.)

1. A method for controlling an ultrasonic surgical device, the method comprising:

Providing electrical energy to a transducer for sealing a blood vessel, wherein the electrical energy has a frequency in the ultrasonic range;

Controlling the electrical energy to achieve a predetermined velocity of an end effector coupled to the transducer while the end effector grasps the blood vessel;

Sensing a parameter of the electrical energy when the end effector achieves the predetermined speed;

Calculating a power of the electrical energy based on the sensed parameter;

Estimating a size range of the blood vessel based on the power; and

controlling the electrical energy to achieve a target speed to seal the blood vessel, the target speed determined based on the estimated size range of the blood vessel.

2. the method of claim 1, wherein the size range of the blood vessel is greater than or equal to 5mm when the power is greater than or equal to a predetermined power threshold.

3. The method of claim 1, wherein the size range of the blood vessel is less than 5mm when the power is less than a predetermined power threshold.

4. The method of claim 1, wherein controlling the electrical energy based on the estimated size range of the blood vessel comprises controlling a power of the electrical energy to seal the blood vessel based on the estimated size range of the blood vessel.

5. The method of claim 1, wherein the power is calculated by subtracting power losses in the transducer and waveguide in the ultrasonic surgical device from the power of the electrical energy.

6. The method of claim 1, wherein the power is calculated about 100 milliseconds after the electrical energy is provided.

7. The method of claim 1, wherein controlling the electrical energy to seal the blood vessel based on the estimated size range of the blood vessel comprises:

determining whether the power is within a first range or a second range, the second range being at least partially higher than the first range; and

Setting a first target speed when the power is determined to be in the first range, and setting a second target speed when the power is determined to be in the second range.

8. The method of claim 7, wherein controlling the electrical energy to seal the blood vessel based on the estimated size range of the blood vessel further comprises:

Controlling the electrical energy to maintain the first target speed or the second target speed of the end effector to seal the blood vessel.

9. the method of claim 7, wherein the first target speed is greater than the predetermined speed.

10. The method of claim 7, wherein the second target speed is less than the predetermined speed.

11. An ultrasonic surgical device comprising:

a transducer;

An end effector coupled to the transducer and configured to grasp and seal a blood vessel;

a power supply configured to supply electrical energy to the transducer;

A sensor configured to sense a parameter of the electrical energy; and

a controller configured to:

Controlling the electrical energy to achieve a predetermined velocity of the end effector coupled to the transducer while the end effector grasps the blood vessel;

Calculating a power of the electrical energy based on the sensed parameter;

Estimating a size range of the blood vessel based on the power; and

Controlling the electrical energy to achieve a target speed to seal the blood vessel, the target speed determined based on the estimated size range of the blood vessel.

12. The ultrasonic surgical device of claim 11, wherein the size range of the blood vessel is estimated to be greater than or equal to 5mm when the power is greater than or equal to a predetermined power threshold.

13. The ultrasonic surgical device of claim 11, wherein the size range of the blood vessel is estimated to be less than 5mm when the power is less than a predetermined power threshold.

14. The ultrasonic surgical device of claim 11, wherein the controller is further configured to control the power of the electrical energy to seal the blood vessel based on the estimated size range of the blood vessel.

15. The ultrasonic surgical device of claim 11, wherein the power is calculated by subtracting power losses in the transducer and waveguide in the ultrasonic surgical device from the power of the electrical energy.

16. The ultrasonic surgical device of claim 11, wherein the power is calculated about 100 milliseconds after the electrical energy is provided.

17. the ultrasonic surgical device of claim 11, wherein the controller is further configured to:

determining whether the power is within a first range or a second range, the second range being at least partially higher than the first range; and

Setting a first target speed when the power is determined to be in the first range, and setting a second target speed when the power is determined to be in the second range.

18. The ultrasonic surgical device of claim 17, wherein the controller is further configured to control the electrical energy to maintain the first target speed or the second target speed of the end effector to seal the blood vessel.

19. The ultrasonic surgical device of claim 17, wherein the first target speed is greater than the predetermined speed.

20. The ultrasonic surgical device of claim 17, wherein the second target speed is less than the predetermined speed.

Technical Field

The present disclosure relates to ultrasonic surgical devices for sealing blood vessels. More particularly, the present disclosure relates to ultrasonic surgical devices that automatically estimate the size range of a blood vessel and control electrical energy to seal the blood vessel.

Background

Ultrasonic surgical devices have been demonstrated to provide excellent hemostasis and effective sealing of tissue with minimal lateral thermal damage and low smoke generation. Unlike electrosurgical devices that require current to flow through a patient, ultrasonic surgical devices operate by applying a mechanical action of a transducer driven at a mechanical resonant frequency.

The size range of the blood vessel varies and therefore the sealing of the blood vessel benefits from the different speeds of the end effector mechanically coupled to the transducer. If a higher velocity is applied to a smaller vessel, the vessel may rupture, and if a lower velocity is applied to a larger vessel, the vessel may not seal adequately. Accordingly, there is a continuing interest in improving vessel sealing to take into account the characteristics of the target vessel.

disclosure of Invention

the present disclosure provides ultrasonic surgical devices for estimating a size range of a blood vessel prior to sealing the blood vessel, and methods for controlling such ultrasonic surgical devices. By maintaining an appropriate speed of an end effector of an ultrasonic surgical device based on an estimated size range of a blood vessel, the ultrasonic surgical device is able to more adequately seal the blood vessel.

According to aspects of the present disclosure, the present disclosure includes a method for controlling an ultrasonic surgical device. The method comprises the following steps: providing electrical energy to the transducer for sealing the blood vessel, wherein the electrical energy has a frequency in the ultrasonic range; controlling the electrical energy to achieve a predetermined velocity of an end effector coupled to the transducer while the end effector is grasping the blood vessel; sensing a parameter of the electrical energy when the end effector achieves a predetermined speed; calculating a power of the electrical energy based on the sensed parameter and estimating a size range of the blood vessel based on the power; and controlling the electrical energy to achieve a target speed to seal the blood vessel, the target speed determined based on the estimated size range of the blood vessel.

In various embodiments, the size range of the blood vessel is greater than or equal to 5 millimeters (mm) when the power is greater than or equal to the predetermined power threshold.

In various embodiments, the size range of the blood vessel is less than 5mm when the power is less than the predetermined power threshold.

in various embodiments, controlling the electrical energy based on the estimated size range of the blood vessel includes controlling the power of the electrical energy to seal the blood vessel based on the estimated size range of the blood vessel.

In various embodiments, the power is calculated by subtracting the power loss in the transducer and waveguide in the ultrasonic surgical device from the power of the electrical energy.

In various embodiments, the power is calculated about 100 milliseconds after the electrical energy is provided.

In various embodiments, controlling the electrical energy to seal the blood vessel based on the estimated size range of the blood vessel comprises: determining whether the power is within a first range or a second range, the second range being at least partially higher than the first range; and setting the first target speed when the power is determined to be in the first range, and setting the second target speed when the power is determined to be in the second range. Controlling the electrical energy to seal the blood vessel based on the estimated size range of the blood vessel includes: the electrical energy is controlled to maintain a first target speed or a second target speed of the end effector to seal the blood vessel. The first target speed is greater than a predetermined speed. The second target speed is less than the predetermined speed.

according to aspects of the present disclosure, the present disclosure includes an ultrasonic surgical device comprising: a transducer; an end effector coupled to the transducer and configured to grasp and seal a blood vessel; a power supply configured to supply electrical energy to the transducer; a sensor configured to sense a parameter of the electrical energy; a controller configured to: while the end effector is grasping the blood vessel, achieving a predetermined velocity of the end effector coupled to the transducer; calculating a power of the electrical energy based on the sensed parameter; estimating a size range of the blood vessel based on the power; and controlling the electrical energy to achieve a target speed to seal the blood vessel, the target speed determined based on the estimated size range of the blood vessel.

In various embodiments, the size range of the blood vessel is greater than or equal to 5mm when the power is greater than or equal to the predetermined power threshold.

In various embodiments, the size range of the blood vessel is less than 5mm when the power is less than the predetermined power threshold.

In various embodiments, the controller is further configured to control the power of the electrical energy to seal the blood vessel based on the estimated size range of the blood vessel.

In various embodiments, the power is calculated by subtracting the power loss in the transducer and waveguide in the ultrasonic surgical device from the power of the electrical energy.

In various embodiments, the power is calculated about 100 milliseconds after the electrical energy is provided.

in various embodiments, the controller is further configured to: determining whether the power is within a first range or a second range, the second range being at least partially higher than the first range; and setting the first target speed when the power is determined to be in the first range, and setting the second target speed when the power is determined to be in the second range. The controller is also configured to control the electrical energy to maintain the first target speed or the second target speed of the end effector to seal the blood vessel. The first target speed is greater than a predetermined speed. The second target speed is less than the predetermined speed.

Further details and aspects of exemplary embodiments of the present disclosure will be described in more detail below with reference to the drawings.

Drawings

The disclosure may be understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1A is a side elevational view of an ultrasonic surgical device according to an embodiment of the present disclosure;

FIG. 1B is a perspective view of a separated portion showing a left side portion of the handle, transducer, and right side portion of an ultrasonic surgical device of FIG. 1A, according to an embodiment of the present disclosure;

FIG. 2 is a functional block diagram of the ultrasonic surgical device of FIG. 1A, according to an embodiment of the present disclosure; and

Fig. 3 is a flow chart illustrating a method for controlling an ultrasonic surgical device according to an embodiment of the present disclosure.

Detailed Description

In general, the present disclosure provides ultrasonic surgical devices for sealing blood vessels in tissue and methods for controlling ultrasonic surgical devices. Ultrasonic surgical devices utilize a transducer to generate ultrasonic mechanical motion. According to aspects of the present disclosure, an ultrasonic surgical device automatically estimates a size range of a blood vessel to be sealed prior to sealing the blood vessel. Based on the estimated size range of the blood vessel, the ultrasonic surgical device maintains the proper speed of the end effector to adequately seal the blood vessel.

In accordance with the present disclosure, an ultrasonic surgical device includes various controls, which may be embodied in hardware and/or software executed by a processor, to control the ultrasonic mechanical motion of a transducer powered by a DC power source. One control is an amplitude control for adjusting the longitudinal modal displacement of the end effector. The other control generates an AC signal from a DC power source and tracks the resonant frequency of the transducer. Through the use of various controls, the ultrasonic surgical device provides controlled ultrasonic mechanical motion sufficient to treat a blood vessel in accordance with embodiments of the present disclosure.

Since different blood vessels benefit from different speeds of the end effector to adequately treat the blood vessel, the ultrasonic surgical device estimates the size range of the blood vessel prior to treating the blood vessel. Based on the estimated size range of the blood vessel, the ultrasonic surgical device sets the speed of the end effector to adequately treat the blood vessel.

Referring to fig. 1A and 1B, an ultrasonic surgical device 100 for treating tissue is shown. The ultrasonic surgical device 100 includes a power source 110, a housing 130, a transducer 150, and an ultrasonic probe 190. The power supply 110 provides DC power to the transducer 150. In one embodiment, the power supply 110 may be a portable power source (such as a battery) that can be carried to provide DC power anywhere. In further embodiments, the power source 110 may be insertable or integrated into the housing 130 such that the ultrasonic surgical device 100 may be carried portably without interference from any cables. In yet another embodiment, the power source 110 may be rechargeable, such that the power source 110 may be reusable. In yet another embodiment, the power supply 110 may receive power from a wall outlet.

in another embodiment, the power supply 110 may include a converter that is connected to an Alternating Current (AC) power source and converts the AC power to DC power. The AC power source may have a relatively low frequency, such as about 60 hertz (Hz), while the ultrasonic surgical device 100 operates at a higher frequency. Thus, the power supply 110 may convert the low frequency AC power to DC power, such that the DC power may then be inverted to AC power having a frequency suitable to cause the transducer 150 to produce ultrasonic mechanical motion.

With continued reference to fig. 1A and 1B, the housing 130 includes a handle portion 131 having a compartment 132 that can receive the power source 110 and a power source door 134 that secures the power source 110 within the compartment 132. In one aspect, the power door 134 may be configured to form a watertight seal between the interior and exterior of the compartment 132.

The housing 130 also includes a cover 133 that houses the transducer 150 and the output device 180. The transducer 150 includes a generator assembly 152 and a transducer assembly 154 having a transducer body 156 and a locking portion 162 (fig. 1B). The generator assembly 152 is electrically coupled to the transducer assembly 154 via a pair of contacts 158.

referring to FIG. 1B, the transducer 150 is shown separated from the cover 133. When the transducer 150 is inserted into and assembled with the cover 133, the pair of contacts 158 couple to the circular groove of the transducer 150 such that rotational movement of the transducer body 156 does not break the connection between the transducer body 156 and the generator assembly 152. Thus, the transducer body 156 is able to rotate freely within the housing 130.

The output device 180 outputs information about the ultrasonic surgical device 100 or, in various embodiments, the status of the mechanical coupling between the ultrasonic probe 190 and the transducer 150. In various embodiments, the output device 180 may also display a warning that the ultrasound probe 190 is not sufficiently connected to the transducer 150.

In another embodiment, the output device 180 may be a speaker configured to output audible tones indicative of a proper or improper connection of the ultrasound probe 190 with the transducer 150. In yet another embodiment, the output device 180 may include one or more light emitting devices configured to emit light of various durations, pulses, and colors indicative of the state of mechanical coupling between the ultrasound probe 190 and the transducer 150.

Handle portion 131 also includes trigger 136. When the trigger 136 is actuated, the power source 110 provides energy to the transducer 150 such that the transducer 150 is powered to produce ultrasonic mechanical motion of the ultrasonic probe 190. When the trigger 136 is released, power to the transducer 150 is terminated.

The generator module 152 receives DC power from the power supply 110 and generates an AC signal having a frequency greater than 20 kHz. The generator assembly 152 may be capable of generating a signal having a frequency based on the desired mode of operation, which may be different from the resonant frequency of the transducer 150.

the transducer body 156 of the transducer assembly 154 receives the AC signal generated by the generator assembly 152 and generates ultrasonic mechanical motion within the ultrasound probe 190 based on the amplitude and frequency of the generated AC signal. The transducer body 156 includes a piezoelectric material that converts the generated AC signal into ultrasonic mechanical motion.

The ultrasonic surgical device 100 also includes a spindle 170 that is coupled to the ultrasonic probe 190 and allows the ultrasonic probe 190 to rotate about its longitudinal axis. The ultrasound probe 190 is attached to the housing and mechanically connected to the transducer 150 via the locking portion 162 such that when the main shaft 170 is rotated about a longitudinal axis defined by the ultrasound probe 190, the ultrasound probe 190 and the transducer 150 are correspondingly rotated without affecting the connection between the transducer 150 and the ultrasound probe 190.

The ultrasound probe 190 may include an end effector adapted to seal tissue. Ultrasound probe 190 includes a waveguide 192, an end effector 194 extending from waveguide 192, and a jaw member 196. The ultrasound probe 190 is mechanically coupled to the transducer body 156 via the locking portion 162.

jaw member 196 can be formed as a pivoting arm configured to grasp and/or clamp tissue between jaw member 196 and end effector 194. As jaw member 196 and end-effector 194 grasp tissue and end-effector 194 transmits ultrasonic mechanical motion, the temperature of the grasped tissue between end-effector 194 and jaw member 196 increases due to the ultrasonic mechanical motion. These motions, in turn, treat (e.g., cut and/or seal) blood vessels in the tissue. In one aspect, end-effector 194 may vibrate at different speeds based on the size range of the vessel to be sealed.

The illustrative embodiment of fig. 1A and 1B is merely exemplary, and variations are contemplated within the scope of the present disclosure. For example, the components need not be arranged or configured as shown in fig. 1A and 1B, and may be arranged or configured in different ways while still performing the operations and/or functions described herein.

Fig. 2 shows a functional block diagram of the ultrasonic surgical device 100 of fig. 1. As described above, ultrasonic surgical device 100 estimates the size range of the vessel to be sealed and provides electrical energy of suitable power and frequency to transducer 150, which in turn provides ultrasonic mechanical motion to end-effector 192. Analog or digital Pulse Width Modulation (PWM) signals may be used to modulate the ultrasonic mechanical motion. Ultrasonic surgical device 100 includes power source 110, converter 330, sensor 340, controller 350, inverter 370, transducer 150, and comparator 390.

The power supply 110 provides DC power to a converter 330 that amplifies the magnitude of the DC power such that the ultrasonic surgical device 100 generates sufficient ultrasonic mechanical motion for treating tissue. Sensor 340 then senses a parameter related to the electrical energy flowing to inverter 370. The sensed parameters may include a sensed current waveform and a sensed voltage waveform of the power supplied to the inverter 370.

The controller 350 receives the sensed parameters from the sensors 340, calculates various parameters (e.g., Root Mean Square (RMS) or average voltage, current, power, or impedance) based on the sensed parameters, and generates control signals to control the duty cycle of the converter 330. In one embodiment, a digital PWM signal may be used to control the duty cycle of converter 330.

The inverter 370 receives the amplified DC signal from the converter 330. Inverter 370 is driven by an output signal from controller 350. In various embodiments, inverter 370 may include an H-bridge structure to generate electrical energy having a suitable frequency to cause transducer 150 to mechanically vibrate.

in various embodiments, controller 350 may measure the velocity of end effector 194 coupled to transducer 150 and maintain a particular velocity of end effector 194 during the sealing process. Comparator 390 receives a signal from transducer 150 indicative of the velocity of end-effector 194 and compares the velocity of end-effector 194 to a predetermined velocity set for estimating the size range of the blood vessel. If the velocity is less than the predetermined velocity, controller 350 may generate a control signal to increase the magnitude of the electrical energy to cause transducer 150 to vibrate further, resulting in an increase in the velocity of end effector 194. If the velocity is greater than the predetermined velocity, the controller 350 may generate another control signal to reduce the magnitude of the electrical energy in order to cause the transducer 150 to vibrate more weakly, resulting in a reduction in velocity.

when the velocity of end effector 194 has achieved a predetermined velocity threshold, the controller may then estimate a size range of the vessel to be treated. Specifically, the controller 350 calculates the power of the electrical energy and estimates the size range of the blood vessel to be treated based on the power. In one embodiment, if the power is less than a predetermined threshold power, the size range of the blood vessel is estimated to be less than 5mm or a small blood vessel: and if the power is greater than or equal to the predetermined threshold power, the size range of the blood vessel is estimated to be greater than 5mm or the blood vessel is larger.

When the supply of electric power is started, it takes time for the speed of the end effector to achieve a predetermined speed. Thus, the time period may be utilized to allow the speed to achieve the predetermined speed. In one aspect, a period of 100 milliseconds (ms) may elapse after the supply of electrical energy has begun before measurement or calculation. However, the time period before measurement or calculation is not limited to 100ms and may be less than or greater than 100 ms.

The controller 350 may generate PWM control signals for driving the converter 330 and other control signals for the inverter 370. Controller 350 receives the output from comparator 390 and generates a control signal for inverter 370 in response to the output of comparator 390. Inverter 370 then inverts the DC power into an AC signal. In one aspect, a transformer (not shown) may be electrically coupled between inverter 370 and transducer 150 such that the transformer may increase or decrease the amplitude of the inverted alternating current to a desired level.

In one aspect, the sensor 340 is configured to sense the voltage and current waveforms of the broadband AC signal supplied to the transducer 150 and transmit the sensor signals to the controller 350. Controller 350 may process the sensor signal and the output of comparator 390 to control the speed of end effector 194.

In one aspect, the controller 350 may include a processor and a memory coupled to the processor. The processor may be any suitable processor (e.g., control circuitry) adapted to perform the operations, calculations and/or sets of instructions described in this disclosure, including but not limited to a hardware processor, a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP), a Central Processing Unit (CPU), a microprocessor, and any combination thereof. Those skilled in the art will appreciate that a processor may be replaced by any logical processor (e.g., control circuitry) suitable for executing the algorithms, calculations and/or instruction sets described in this disclosure. The memory may include one or more of volatile, non-volatile, magnetic, optical, or electronic media, such as read-only memory (ROM), Random Access Memory (RAM), electrically erasable programmable ROM (eeprom), non-volatile RAM (nvram), or flash memory.

Fig. 3 shows a flow chart illustrating a method 300 for controlling an ultrasound transducer to substantially seal a blood vessel. The method 300 includes two stages, one of which achieves a predetermined velocity at the end effector, and another of which determines a size range of the vessel to be sealed and sets the velocity of the end effector accordingly.

A first control of method 300 begins with supplying electrical energy to a transducer in step 305 when an end effector coupled to the transducer grasps tissue comprising a blood vessel. The electrical energy includes a frequency and an amplitude that control the speed of an end effector mechanically coupled to the transducer. In step 310, the mechanical motion of the transducer is measured and the speed of movement of the end effector is calculated.

Since vessels of a larger size range typically require more electrical energy to maintain velocity, the measured velocity is compared to a threshold velocity in step 315. When it is determined that the velocity of the end effector is less than the threshold velocity, more electrical energy is supplied to the transducer in step 320. When it is determined that the velocity of the end effector is greater than the threshold velocity, less electrical energy is supplied to the transducer in step 325. In this way, the speed of the end effector is controlled to achieve a predetermined speed.

When it is determined in step 315 that the speed has achieved the threshold speed, the power of the supplied electrical energy is calculated in step 330. In one aspect, the comparison in step 315 may be performed some period of time after the end effector is actuated, as the velocity of the end effector may take time to achieve the predetermined velocity. The predetermined period of time may be 100ms, for example.

In one aspect, power may be calculated from the sensing results. For example, the power may be calculated by multiplying the voltage waveform by the current waveform. In another aspect, the power may be calibrated to calculate the power actually applied to the tissue. The calculation may be performed by subtracting the power losses in the waveguide and the transducer from the result obtained by multiplying the voltage waveform by the current waveform. In addition, the predetermined power threshold may also be set based on the type of tissue comprising the vessel to be treated.

In various embodiments, the power loss in the transducer may be based on variability in the characteristics of the piezoelectric stack of the transducer. The power calibration process may involve open jaw activation to determine scaling factors for voltage, current, speed, and frequency measurements, and may include measuring the power drawn for open jaw activation. In an embodiment, calibration parameters associated with the transducer may be stored in memory for use in a later power calibration process.

In various embodiments, the power loss in the waveguide and in the transducer may be calibration values stored in a memory of the ultrasound device. The length of the waveguide may vary, resulting in different power losses therein. Parameters related to power loss based on waveguide length may be stored in memory and may be read from memory to calibrate power loss while estimating size ranges and performing vessel sealing.

Based on the calculated power, a size range of the blood vessel may be determined in step 335. For example, if the calculated power is below a predetermined power threshold, the blood vessel is determined to be a small blood vessel of less than 5 mm. If the calculated power is greater than or equal to the predetermined power threshold, the blood vessel is determined to be a large blood vessel greater than or equal to 5mm and less than 7 mm.

In one aspect, the predetermined power threshold may be set differently based on the type of vessel. For example, the predetermined power threshold for the renal artery may be different than the predetermined power threshold for the carotid or femoral artery.

The calculated power is then compared to the two ranges to set a target velocity of the end effector to adequately seal the vessel in step 340. When the calculated power falls within the first range or the blood vessel is determined to be a small blood vessel, the target speed is set to be greater than the predetermined speed in step 345. For example, if the calculated power is between 18 watts (W) and 23.5W, the target speed is increased.

when the calculated power falls within a second range higher than the first range or the blood vessel is determined to be a large blood vessel, the target speed is set to be less than the predetermined speed in step 350. For example, if the calculated power is between 26.5W and 36W, the target speed is reduced. The values of the first range and the second range are provided only as examples, and the first range and the second range are not limited to these values and may have different values.

In step 355, power is controlled to maintain the speed of the end effector at the target speed. The vessel is then substantially sealed at the target speed and the method 300 ends. In one aspect, the duration of the sealing process may be controlled depending on the size range of the blood vessel. In other words, small blood vessels can be sealed more quickly than large blood vessels.

In various embodiments, step 315 may not proceed to step 330 when the speed achieves the predetermined speed threshold. Rather, in various embodiments, step 315 may only proceed to step 330 after a certain period of time (such as 100ms) has elapsed.

In various embodiments, step 345 may not only increase the target speed, but step 350 may not only decrease the target speed. In various embodiments, step 345 may access a first speed profile and step 350 may access a second speed profile. As used herein, a speed profile is a function, table, or other numerical relationship that specifies speed over time. Step 355 will then control the power such that the velocity of the end effector tracks a particular velocity profile over time.

Since other modifications and changes may be made to adapt to particular operating requirements and environments, it should be understood by those skilled in the art that the present disclosure is not limited to the illustrative examples described herein, and that various other changes and modifications may be made without departing from the spirit or scope of the disclosure.