1. Safety Monitors in Hemodialysis 209
It should be remembered that the venous pressure monitor reflects PBO in the
equation TMP = PBO PDO. High venous pressures can result in too high ultrafiltra-
tion rates unless an ultrafiltration-controlled machine is being used.
惺愕 悋惘惆 悋惷愃愀 悋愕 悴悋慍 悖 惠悵惘 悖 悴惡
PBO
悋惺悋惆悸
TMP = PBO - PDO
.
悋惠忰 惠 悛悸 悋愕惠悽惆悋 惠 悋 悋惆悴 惺悋悸 悋悧悸 惠惘愆忰 惺惆悋惠 悒 悋惺悋悸 悋惘惆悸 悋惷愃愀 惠悗惆 悖
.悋悋悧 悋惠惘愆忰 愀惘 惺 悋
Air-Foam Detector
悋悋悄 惘愃悸 悋愆
The air-foam detector monitors blood in the venous tubing (Fig. 13.13) for the pres-
ence of air, foam, and microbubbles. It must be reemphasized that with almost all
internal AV fistulas/grafts and all venovenous dialysis, a significant subatmospheric
pressure exists between the arterial access and the roller pump. There are many
junctions and heat-sealed joints in this portion of the circuit.
(悋愆 悋惘惆 悋悖惡惡 悋惆 悋悋悧悸 悋惘愃悸 悋愆 惘悋惡
13.13
悋悋惺悋惠 悋惘愃悸 悋悋悄 悴惆 )
悒惺悋惆 悴惡 .悋惆悸
悋 愃愕 惺悋惠 悴惺 悋惡惠惘 悋惆悋悽悸 悋愀惺 / 悋悋愕惘 悴惺 惺 悖 惺 悋惠悖惆 悸
悋惺惆惆 悋 .悋惆悋惘悸 悋惷悽悸 悋愆惘悋 悋惶 惡 悋悴 悋愃悋 惠忰惠 惡惘 惷愃愀 悴惆 悋惘惆
.悋惆悋悧惘悸 悋悴慍悄 悵悋 惡悋忰惘悋惘悸 悋悽惠悸 悋悋惶 悋惶悋惠
If the heparin infusion line is in the negative-pressure segment rather than post
blood pump, it may increasethe risk for air entry. After the blood pump, the blood
circuit is at considerable positive pressure and air can enter only by pumping or
injecting it into the remainder of the circuit. Air embolism is a preventable and
very serious dialysis misadventure.
.悋悋悄 惆悽 悽愀惘 慍惆 惆 惡惺惆 悋惆 惷悽 悋惡惆 悋愕惡 悋惷愃愀 愀悋惺 悋惡悋惘 惷悽 悽愀 悋 悒悵悋
惷悽 愀惘 惺 悒悋 惆悽 悖 悋悄 悋 惡惘 悒悴悋惡 惷愃愀 惺惆 悋惆悸 悋惆悋悧惘悸 惠 悋惆 惷悽悸 惡惺惆
.悋惆悋悧惘悸 惡悋 忰 悖
悋悋悧 悋悋愕惆悋惆
愃悋悸 悽愀惘 忰悋惆惓
.悋 愃愕 悋悋悸
2. 210 Safety Monitors in Hemodialysis
Two types of air-foam detectors are in use:
the ultrasonic and the reflected light detectors. It is believed that only the
ultrasonic device is currently being sold. Nevertheless, many of the reflected light-
type devices are still in use. Surprisingly, there are no standards for permissible
detection of air because either type of detector readily identifies gross air
displacement of blood in the venous drip chamber when properly armed and
functioning. Microbubbles from 5 to 500 袖m in diameter rep- resent a different
problem as they stream along with the blood flow. These micro- bubbles are
entrained in the bloodstream
悖 :悋悋悧悸 悋惘愃悸 惺 悋愆 悖悴慍悸 惺 悋愕惠悽惆悋 惠
悋惶惠悸 惡悋悴悋惠 悋愆 悴慍悸
.悋忰悋 愀 悋惶惠悸 悋悴悋惠 悴悋慍 惡惺 惠 悖 菏惠惆 .悋惺愕 悋惷悄 惺 悋愆 悖悴慍悸
悵 惺
.悋悋愕惠悽惆悋 惆 惠慍悋 悋 悋惺愕 悋惷悄 惺 悋悖悴慍悸 悋惺惆惆 悒
惆愆悸 悋惓惘
惺悋惘 惠悴惆 悋 悖
惡 悋愕忰 愆
悋悋 惺
愃惘悸 惆 悋悒悴悋悸 悋悋悄 悒慍悋忰悸 惡愕悸 忰惆惆 悋悋愆悋惠 惺 悖 悖 悄
愀惘悋 惠惘悋忰 悋惠 悋惆悸 悋悋惺悋惠 惠惓 .惶忰忰 惡愆 惠愆愃悋 惠愕忰悋 惺惆 悋惘惆 悋惠愀
5
悒
500
悋惆悸 悋悋惺悋惠 悵 悒惆悽悋 惠 .悋惆 惠惆 惺 惠惠惆 悖悋 悽惠悸 愆悸 惘惠惘
悋惆 悴惘
Air-Foam Detector. (From Pittard J: Hemodialysis Nursing, Training Manual,
7th ed., version 7.0. Santa Monica, CA, 2003, with permission.)
sensor
Line clamp
Figure 13.13
3. Safety Monitors in Hemodialysis 211
Although both types of monitors can detect microbubbles, their guaranteed detec-
tion requires a sensitivity setting that may result in many false alarms because of
turbulence in fluid flow. The compromise is a sensitivity adjustment of the ultrasonic
devices such that some false alarms occur that require the attention of dialysis per-
sonnel. In certain situations, microbubbles can go undetected and cause clinical air
embolism.
悋惷 悋惠愆悋悋 悒 悋惆悸 悋悋惺悋惠 惠愆 悖 悋愆悋愆悋惠 悋惺 悋 悖 悋惘愃 惺
悋悒悵悋 悋惺惆惆 惺 惠悴 惆 忰愕悋愕悸 悒惺惆悋惆 惠愀惡
.悋愕悋悧 惠惆 悋惷愀惘悋惡 惡愕惡惡 悋悽悋愀悧悸 惘悋惠
悋愕愀 悋忰
悋惠惡悋 惠惠愀惡 悋惠 悋悋悵惡悸 悋悒悵悋惘悋惠 惡惺惷 惠忰惆惓 惡忰惓 悋惶惠悸 悋悴悋惠 悖悴慍悸 忰愕悋愕悸 惠惺惆
惠愕惡惡 悋惆悸 悋悋惺悋惠 惠悽惠 悖 惺悸 忰悋悋惠 .悋 愃愕 惴
悋悒 悋悋悧 悋惆悋愕惆悋
.
The current standards for these devices require response to air in blood,a blood
and saline mixture, or saline. Only the ultrasonic device can meet this requirement.
A dangerous aspect of the reflected light device is that it is effective only when
sensing the whole blood of the patient. It cannot be accurately armed during
priming, initiation, or rinsing.
悋忰 悖 悋忰 悋忰 悋惆 悽愀 悖 悋惆 悋悄 悋悋愕惠悴悋惡悸 悋悖悴慍悸 悵 悋忰悋悸 悋惺悋惘 惠惠愀惡
惠 .悋愀惡 悵悋 惠惡悸 悋惶惠悸 悋悴悋惠 悴悋慍 愀 .悋忰
悴悋慍 悋悽愀惘悸 悋悴悋惡 悖忰惆 惓
悖惓悋悄 惡惆悸 惠愕忰悋 悋 .惘惷 悋悋 悋惆 悋愕惠愆惺悋惘 惺惆 悒悋 悋惺悋 悋 悖 悋惺愕 悋惷悄
悋惠忰惷惘
.悋愆愀 悖 悋惡惆悄 悖
Venous Line Clamp
悋惘惆 悋悽愀 愆惡
An air detector alarm must activate the venous line clamp (Fig. 13.13). The venous
line clamp must completely occlude the venous blood line and withstand an intra-
luminal pressure of 800 mm Hg. The venous line clamp should be constructed as to
not damage the blood lines, and should not restrict the blood tubing when in an open
position. The venous line clamp circuitry must interface with and stop the blood
pump. Most integrated air-foam detectors meet all of these standards.
(悋愆 悋惘惆 悋悽愀 愆惡 惡惠愆愀 悋悋悄 悋愆 悒悵悋惘 悖 悴惡
13.13
悋悽愀 愆惡 愕惆 悖 悴惡 .)
惡愃 悋惺悸 惆悋悽 悋愀惷愃 惠忰 悖 悋惘惆 悋惆 悽愀 悋惠悋 悋惘惆
800
悋悽愀 愆惡 悒愆悋悄 悴惡 .慍悧惡
惠惠悋惺 悖 悴惡 .惠忰 惷惺 惠 惺惆悋 悋惆 悖悋惡惡 惆 悖悋 悴惡 悋惆 悽愀愀 惠 悋 惡忰惓 悋惘惆
悖悴慍悸 惺惴 惠惡 .惠悋 悋惆 惷悽悸 惺 悋惘惆 悋悽愀 愆惡 惆悋惘悸
悋惠悋悸 悋悋悧悸 悋惘愃悸 惺 悋愆
.悋惺悋惘 悵
There are dialysis machines, which are unsafe as they include the ability to
dialyze with both the air-leak detector and venous line clamp disarmed and only
some marginal indication of this disarmed state.
惠愕惘惡 悋愆 惺 悋 愃愕 惺 悋惆惘悸 惠惠惷 悖悋 悛悸 愃惘 悋 愃愕 悛悋惠 悋
.悵 悋愕悋忰 慍惺 忰悋悸 惺 愀 悋悋愆悸 悋悗愆惘悋惠 惡惺惷 惺 愃惘 悋惘惆 悋悽愀 愆惡 悋悋悄
Air-Foam Detector and Venous Line Clamp Monitoring
悋悋悄 惘愃悸 悋愆
悋惘惆 悋悽愀 惘悋惡悸
With an air-foam detector alarm state, identify that the venous line clamp is
engaged and that the blood pump is stopped. Visually inspect the entire blood
circuit from the venous access backward to the arterial end for the presence of
air, foam, or microbubbles.
.惠悸 悋惆 惷悽悸 悖 愆愃 悋惘惆 悋悽愀 愆惡 悖 忰惆惆 悋悋悧悸 悋惘愃悸 悋愆 悒悵悋惘 忰悋悸 惡悋愕惠悽惆悋
悖 悋悄 悴惆 惺 悋惓惡忰 悋愆惘悋 悋悸 悒 悽 悋惘惆 悋惶 惡悖悋 悋惆 惆悋悧惘悸 悋惡惶惘 悋忰惶
.惆悸 悋惺悋惠 悖 惘愃悸
4. 212 Safety Monitors in Hemodialysis
Check the level in the venous drip chamberit should be three quarters full.
Check that the venous drip chamber is properly placed inits holder, the level
detector door is closed and latched, and the mesh in the drip chamber is below the
air detector. Also, check if the air sensors are clean. Always validate the absence of
air before restarting the blood pump and disengaging the venous line clamp. If air is
present, disconnect the patient from the extracorporeal circuit.
悋惘惆 悋惠愀 忰悴惘悸 悋愕惠 悋忰惶
-
悴惡
悋惠愀 愃惘悸 悖 惠忰 .悖惘惡悋惺 惡惓悋惓悸 惠悧悸 惠 悖
悋悴惆悸 悋愆惡悸 悖 愃 愃 悋愕惠 悋愆 惡悋惡 悖 忰悋悋 惶忰忰 惡愆 惷惺悸 悋惘惆
惺惆 悋惆悋悧 惠忰 .惴悸 悋悋悄 愕惠愆惺惘悋惠 悋惠 悒悵悋 悋 悋惷悖 惠忰 .悋悋悄 悋愆 悖愕 悋惠愀 愃惘悸
悋悋悄 悴惆
悋惘惷 悋惶 悋悄 悴惆 忰悋悸 .悋惘惆 悋悽愀 愆惡 悋惆 惷悽悸 惠愆愃 悒惺悋惆悸 惡
.悋悴愕 悽悋惘悴 悋惆悋悧惘悸 惺
Before beginning dialysis, make sure that the air-foam detector is turned on and
operational and that the venous blood line is properly placed in the line-clamp holder.
Ultrasonic devices are usually activated during priming of the circuit. Reflected light
devices cannot be activated until whole blood at full hematocrit is in the venous
tubing.
悋悋悧悸 悋惘愃悸 悋愆 惠愆愃 惠悖惆 悋 愃愕 悋惡惆悄 惡
悋惘惆 悋惆 悽愀 悖 惠愆愃
惠忰惷惘 悖惓悋悄 悋惶惠悸 悋悴悋惠 悖悴慍悸 惠愆愀 惠 悋 惺悋惆悸 .悋悽愀 愆惡 忰悋 惶忰忰 惡愆 惷惺
悋悖惡惡 悋悧惠 悋悋惠惘惠 悋悋 悋惆 惶惡忰 忰惠 悋惺愕 悋惷悄 悖悴慍悸 惠愆愀 悋 .悋惆悋悧惘悸
.悋惘惆
Because each brand of detector varies in its operation, ensure that dialysis person-
nel are aware of the type of device used in the facility and are in-serviced on
its unique features and operation. Unfortunately, when staff pushes the RESET/
RESTART button in responding to this alarm condition, the blood pump restarts.
This can be a potentially deadly response.
惆惘悋悸 惺 悋 愃愕 惴 悖 惠悖惆 惠愆愃悋 惠悽惠 悋悋愆 惠悴悋惘悸 惺悋悸 悖 悋惴惘
愕 .惠愆愃 悋惘惆悸 慍悋惠 悽悋 悽惆惠 惠 悋愆悖悸 悋愕惠悽惆 悋悴悋慍 惡惺
惷愃愀 惺惆悋 悋忰惴 悄
慍惘 惺 悋惴
RESET / RESTART
.悋惆 惷悽悸 惠愆愃 悒惺悋惆悸 惠惠 悵 悋悒悵悋惘 忰悋悸 悸悋愕惠悴悋惡
.悋惠悸 悋愕惠悴悋惡悸 悵 惠 悖
Microbubbles that may not be visible to the naked eye can then flow into the
patient. I advise staff to manually turn off the blood pump when responding to an
air in blood alarm. After all inspections are complete, pushing the reset button will
not automatically start the blood pump. However, if the problem is not corrected,
the alarm will reoccur with no harm to thepatient.
悋惴 悖惶忰 .悋惘惷 悒 悋悴惘惆悸 惺 惘悧悸 惠 悋 惆 悋惠 悋惆悸 悋悋惺悋惠 惠惠惆 悖
悋忰惶 惺悋惠 悴惺 悋惠悋 惡惺惆 .悋惆 悒悵悋惘 悋悄 悋悋愕惠悴悋惡悸 惺惆 悋惆 悋惆 惷悽悸 惠愆愃 惡悒悋
悋惠悋悧 悋惆 惷悽 惡惆悄 悒 悋惷惡愀 悒惺悋惆悸 慍惘 惺 悋惷愃愀 悗惆
悋愆悸 惠惶忰忰 惠 悒悵悋 悵 惺 .
.惡悋惘惷 悋悒惷惘悋惘 惆 悋悒悵悋惘 惠惘惘 愕
5. Safety Monitors in Hemodialysis 213
Four alarm conditions are outlined here for general information.
.惺悋悸 惺悋惠 惺 忰惶 悋 惷忰悸 悒悵悋惘 愆惘愀 悖惘惡惺悸
Alarm Condition 1. Careful inspection reveals that the blood-air level in the venous
drip chamber is normal and that there are no microbubbles (foam) in any portion
of the line or dialyzer. This is a false alarmrelease the line clamp and reset the
detector.
悋悒悵悋惘 忰悋悸
1
愕 悖 悋惆 悋忰惶 愆 .
惠悴惆 悋 悖 愀惡惺 悋惘惆 悋惠愀 愃惘悸 悋惆 悋悄 惠
悋悵惡 悒悵悋惘 悵悋 .悋 愃愕 悴悋慍 悖 悋悽愀 悴慍悄 悖 )(惘愃悸 惶愃惘悸 悋惺悋惠
-
悋悽愀 愆惡 忰惘惘
.悋悋愆 惷惡愀 悖惺惆
Alarm Condition 2. The blood level in the venous drip chamber has fallen. In
response, check for upstream bubbles; if none is present, return the blood-air level
to normal in the drip chamber with the usual technique, release the line clamp,
and reset the alarm.
悋悒悵悋惘 忰悋悸
2
悴惆 惠忰 悵 惺 惘惆悋 .悋惘惆 悋惠愀 忰悴惘悸 悋惆 愕惠 悋悽惷 .
悋惺悋惠
悋惠愀 愃惘悸 愀惡惺惠 悒 悋悋悄 悋惆 愕惠 惡悒惺悋惆悸 愆悄 悖 悴惆 惺惆 忰悋悸 悋惡惺
.悋惡 惷惡愀 悖惺惆 悋悽愀 愆惡 忰惘惘 惓 悋惺惠悋惆悸 惡悋愀惘悸
Alarm Condition 3. There are microbubbles (foam) in the venous line. In response,
clamp the venous line and the venous access line, directing attention to the patient
in the event that emergency management of air embolism is necessary. Another
person should remove the line from the air detector clamp, disconnect the patient
from the blood circuit, and aseptically join the arterial and venous ends of the
blood circuit for recirculation.
悋悒悵悋惘 忰悋悸
3
悋惘惆 悋悽愀 惡惘惡愀 悵 惺 悋惘惆 .悋惘惆 悋悽愀 )(惘愃悸 惶愃惘悸 悋惺悋惠 悋 .
悋 悒惆悋惘悸 悒 悋忰悋悴悸 忰悋悸 悋惘惷 悒 悋悋惠惡悋 惠悴 惺 悋惘惆 悋惶 悽愀
悋愕惆悋惆 愀悋惘悧
悋惆 惆悋悧惘悸 惺 悋惘惷 惶 悋悋悄 悋愆 愆惡 悋悽愀 悒慍悋悸 悛悽惘 愆悽惶 惺 悴惡 .悋悋悧
.悋惆惘悋 悒惺悋惆悸 悋惆悸 惆悋悧惘悸 悋悖惘惆悸 悋愆惘悋 愀惘 悋惺 惘惡愀
Remove ultrafiltration, and open the saline to remove air from the blood circuit
and to collect it in the venous drip chamber. If this measure is successful, place
the venous line into the air-detector line clamp and rearm the air-foam detector.
If no further alarm is activated, reconnect the blood circuit lines to the patient
and reinitiate dialysis.
悋惠愀 愃惘悸 惠悴惺 悋惆 惆悋悧惘悸 悋悋悄 悒慍悋悸 悋忰 悋忰 悋惠忰 悋悋悧 悋惠惘愆忰 惡悒慍悋悸
悋愆 惠愕忰 悖惺惆 悋悋悄 悋愆 悽愀 愆惡 悋惘惆 悋悽愀 惷惺 悋悒悴惘悋悄 悵悋 悴忰 悒悵悋 .悋惘惆
悖惺惆 悛悽惘 悒悵悋惘 悖 惠愆愀 惠 悒悵悋 .悋悋悧悸 悋惘愃悸
愃愕 悖惺惆 惡悋惘惷 悋惆 惆悋悧惘悸 悽愀愀 惠惶
.悋
Alarm Condition 4. Gross air and bubbles fill the entire blood circuit, including the
dialyzer. In response, clamp the venous line and direct attention to the patient
for emergency management of air embolism. Dispose of the entire blood circuit,
including the dialyzer, and set up a new one to reinitiate dialysis.
悋悒悵悋惘 忰悋悸
4
悋愕惠悴悋惡悸 .悋 愃愕 悴悋慍 悵 惡悋 惡悖悋 悋惆 惆悋悧惘悸 悋悋惺悋惠 悋悒悴悋 悋悋悄 悖 .
悋悋惠惡悋 惠悴 ""悋惘惆 悋悽愀 惡惘惡愀 悵
忰悋悋惠 悋悋悧 悋悋愕惆悋惆 忰悋悋惠 悒惆悋惘悸 悋惘惷 悒
悒惺悋惆悸 悴惆惆悸 惆悋悧惘悸 惡悒惺惆悋惆 悋 愃愕 悴悋慍 悵 惡悋 惡悖悋 悋惆 惆悋悧惘悸 惠悽惶 .悋愀悋惘悧
.悋 愃愕