The pulse oxygen saturation and end-tidal CO2 of the middle finger in laparoscopic surgery suddenly drop, so beware of gas embolism!

With the development of medical technology, it is often necessary to pressurize air or other gases (most commonly CO2 ) and liquids into body cavities in medical examinations and surgical operations to provide sufficient operating space, and may also cause air and other gases to enter the blood circulation.

With the development of medical technology, it is often necessary to pressurize air or other gases (most commonly CO2 ) and liquids into body cavities in medical examinations and surgical operations to provide sufficient operating space, and may also cause air and other gases to enter the blood circulation.

In clinical work, insufflation pressure can often be monitored, but the volume of insufflated gas can rarely be measured or quantified

The occurrence of CO2 embolism during endoscopic surgery is one of the crises in clinical anesthesia management .

The patient, female, 27 years old, BMI 19kg/m2 , ASA class I, previously healthy, planned to undergo transanal and laparoscopic total mesorectal excision ( TaTME )

Cardiopulmonary function was normal in preoperative examination, and no abnormality was found in all test indexes

The pressure of pneumoperitoneum was 12mmHg , and the pressure of anal endoscope was 15mmHg .

PLAT and PEAK suddenly increased to 25-30cmH2O , SpO2 decreased to 70-80% , blood pressure decreased to 70/50mmHg , HR 110mmHg , palpation felt snow on the neck and chest area, and breath sounds in both lungs were significantly weakened by auscultation.

Inhalation of pure oxygen, rapid volume expansion and application of norepinephrine to increase blood pressure, while the patient is placed in a left lateral decubitus position with head down Learning is gradually normal .

Subsequently, the pressure of the anal endoscope was reduced to 12 mmHg and the wound was stopped in time

From this case, we should be able to feel that CO2 embolism is a serious complication that anesthesiologists need to be vigilant about during endoscopic surgery

There are three factors in the occurrence of air embolism: air source, vascular rupture, and pressure difference between the inside and outside of the blood vessel

Figure 1 : Flow chart of venous air embolism crisis management

Figure 1 : Flow chart of venous air embolism crisis management

 

pathophysiological manifestations

pathophysiological manifestations

CO2 embolism is a special complication of laparoscopic surgery, which generally occurs during or shortly after gas injection, mainly due to misintroduction of CO2 into blood vessels or parenchymal organs

CO2 embolism is a special complication of laparoscopic surgery, which generally occurs during or shortly after gas injection, mainly due to misintroduction of CO2 into blood vessels or parenchymal organs

A typical air embolism needs to meet three conditions:

1.

1.

2.
A certain pressure difference is required, that is, the venous pressure is relatively lower than the atmospheric pressure
.

3.
Direct or indirect external pressure pushes the gas into the blood
.
Its severity depends on the type and amount of gas and the rate at which the gas enters the vein
.

3.
Direct or indirect external pressure pushes the gas into the blood
.
Its severity depends on the type and amount of gas and the rate at which the gas enters the vein
.

The emboli first form an " air lock " .
Large air bubbles may block the right atrium and reduce cardiac output; small air bubbles may remain in the lungs, causing pulmonary hypertension, right heart failure, and pulmonary edema
.
Animal experimental studies speculate that the lethal dose for adults is 200~300ml
.
Venous air emboli can also enter the arterial circulation through an arterial atrial septal defect or patent foramen ovale, termed " paradoxical embolism "
.

The emboli first form an " air lock " .
Large air bubbles may block the right atrium and reduce cardiac output; small air bubbles may remain in the lungs, causing pulmonary hypertension, right heart failure, and pulmonary edema
.
Animal experimental studies speculate that the lethal dose for adults is 200~300ml
.
Venous air emboli can also enter the arterial circulation through an arterial atrial septal defect or patent foramen ovale, termed " paradoxical embolism "
.

In fact, a certain percentage of air emboli will occur in open surgery, but these air emboli are caused by air, not only CO2 .
Compared with air, the high solubility of CO2 makes the embolism less severe .

In fact, a certain percentage of air emboli will occur in open surgery, but these air emboli are caused by air, not only CO2 .
Compared with air, the high solubility of CO2 makes the embolism less severe .

CO2 has now become the best choice for a dilating gas because it is chemically inert, colorless, inexpensive, readily available, and basically non-flammable
.
What's more, the blood solubility of CO2 is 50 times that of air, and it is safer when the same volume of gas enters the circulation .

CO2 has now become the best choice for a dilating gas because it is chemically inert, colorless, inexpensive, readily available, and basically non-flammable
.
What's more, the blood solubility of CO2 is 50 times that of air, and it is safer when the same volume of gas enters the circulation .

But we must keep in mind that CO2 is closely related to hypercapnia, metabolic and respiratory acidosis, activation of the sympathetic nervous system, changes in the immune stress system
.

But we must keep in mind that CO2 is closely related to hypercapnia, metabolic and respiratory acidosis, activation of the sympathetic nervous system, changes in the immune stress system
.
immunity

CO2 embolism usually manifests as systemic hypotension, dyspnea, cyanosis, tachycardia or bradycardia, arrhythmia and cardiac arrest, etc.
Auscultation can hear a " grinding wheel-like " murmur, PETCO2 rises or falls, and pulmonary artery can be monitored Hypertension, increased central venous pressure, hypoxemia, and increased arterial carbon dioxide partial pressure
.

CO2 embolism is often manifested as systemic hypotension, dyspnea, cyanosis, tachycardia or bradycardia, arrhythmia and cardiac arrest, etc.
Auscultation can hear arrhythmia " grinding wheel-like " murmurs, and PETCO2 increases or decreases, which can be monitored.
to pulmonary hypertension, increased central venous pressure, hypoxemia, and increased arterial carbon dioxide partial pressure
.

Influencing factors

Influencing factors

A series of studies using transesophageal echocardiography ( TEE ) to monitor intraoperative carbon dioxide embolism have shown that the incidence of CO2 embolism caused by different types of endoscopy or surgery is different, and the size and harm of gas emboli are also different .

A series of studies using transesophageal echocardiography ( TEE ) to monitor intraoperative carbon dioxide embolism have shown that the incidence of CO2 embolism caused by different types of endoscopy or surgery is different, and the size and harm of gas emboli are also different .

Among them, the incidence of CO2 embolism is higher in gynecological surgery, especially hysteroscopic surgery, urological prostate surgery, laparoscopic liver resection, and endoscopic thyroid surgery through the oral vestibular approach .
The main reasons are as follows:

Among them, the incidence of CO2 embolism is higher in gynecological surgery, especially hysteroscopic surgery, urological prostate surgery, laparoscopic liver resection, and endoscopic thyroid surgery through the oral vestibular approach .
The main reasons are as follows:

1.
The operation space is relatively small
.
The narrow space leads to high local CO2 pressure.
Once the vein is damaged, it is easier for CO2 to enter the vein under high pressure, resulting in the occurrence of CO2 embolism .

1.
The operation space is relatively small
.
The narrow space leads to high local CO2 pressure.
Once the vein is damaged, it is easier for CO2 to enter the vein under high pressure, resulting in the occurrence of CO2 embolism .

2.
The surgical site is prone to bleeding
.
For example, organs such as liver, kidney, prostate, and uterine appendages are rich in blood supply, and they are prone to bleeding during the operation, so that CO2 enters the circulation from the damaged vein, resulting in CO2 embolism
.

2.
The surgical site is prone to bleeding
.
For example, organs such as liver, kidney, prostate, and uterine appendages are rich in blood supply, and they are prone to bleeding during the operation, so that CO2 enters the circulation from the damaged vein, resulting in CO2 embolism
.

3.
Head down
.
In gynecological laparoscopic surgery and prostate laparoscopic surgery, the head position is generally adopted.
When the head is lowered, the operating area is higher than the heart, which reduces the venous pressure in the operating area and makes it easier for CO2 to enter through the damaged vein
.

3.
Head down
.
In gynecological laparoscopic surgery and prostate laparoscopic surgery, the head position is generally adopted.
When the head is lowered, the operating area is higher than the heart, which reduces the venous pressure in the operating area and makes it easier for CO2 to enter through the damaged vein
.

4.
Not equipped with constant pressure and automatic smoke removal AirSeal pneumoperitoneum
.
The AirSeal pneumoperitoneum responds immediately to small changes in intra-abdominal pressure, provides continuous pressure sensing and stable pneumoperitoneum, and can continuously expel smoke
.

4.
Not equipped with constant pressure and automatic smoke removal AirSeal pneumoperitoneum
.
The AirSeal pneumoperitoneum responds immediately to small changes in intra-abdominal pressure, provides continuous pressure sensing and stable pneumoperitoneum, and can continuously expel smoke
.

In the absence of an AirSeal pneumoperitoneum machine, in order to reduce smoke, a suction device should be used for continuous suction during the operation.
In order to offset this pressure loss, the pneumoperitoneum pressure and flow rate will be artificially set at a high level, which will lead to CO2 The incidence of embolism is increased
.

In the absence of an AirSeal pneumoperitoneum machine, in order to reduce smoke, a suction device should be used for continuous suction during the operation.
In order to offset this pressure loss, the pneumoperitoneum pressure and flow rate will be artificially set at a high level, which will lead to CO2 The incidence of embolism is increased
.

5.
Preoperative fasting and bowel preparation
.
As a result, patients generally suffer from insufficient fluid volume, low central venous pressure, and more prone to CO2 embolism after vascular injury
.

5.
Preoperative fasting and bowel preparation
.
As a result, patients generally suffer from insufficient fluid volume, low central venous pressure, and more prone to CO2 embolism after vascular injury
.

timely diagnosis

timely diagnosis _

TEE is the most sensitive method for monitoring air emboli, which can be detected by intravenous injection of a small amount of carbon dioxide ( 0.
1mL/kg ), but it is currently difficult to carry out clinically, and in most cases the emboli are small in size and have no clinical significance , the early diagnosis of severe air embolism is relatively difficult
.

TEE is the most sensitive method for monitoring air emboli, which can be detected by intravenous injection of a small amount of carbon dioxide ( 0.
1mL/kg ), but it is currently difficult to carry out clinically, and in most cases the emboli are small in size and have no clinical significance , the early diagnosis of severe air embolism is relatively difficult
.

A sudden drop in PETCO2 may be an important sign for early detection of CO2 embolism, but can the value of PETCO2 correctly reflect PCO2 ? Under normal circumstances, PETCO2 will be 6~8mmHg lower than PCO2 , and during CO2 embolism, PETCO2 will increase due to CO2 absorption, and PCO2 may be higher at this time, so further analysis must be combined with arterial blood gas .

 

A sudden drop in PETCO2 may be an important sign for early detection of CO2 embolism, but can the value of PETCO2 correctly reflect PCO2 ? Under normal circumstances, PETCO2 will be 6~8mmHg lower than PCO2 , and during CO2 embolism, PETCO2 will increase due to CO2 absorption, and PCO2 may be higher at this time, so further analysis must be combined with arterial blood gas .

 

When PETCO2 suddenly drops, it is necessary to respond quickly and check the circuit of the instrument and the breathing circuit.
After these factors are ruled out, CO2 embolism should be highly suspected
.

When PETCO2 suddenly drops, it is necessary to respond quickly and check the circuit of the instrument and the breathing circuit.
After these factors are ruled out, CO2 embolism should be highly suspected
.

Typically , about half of patients show some form of cardiovascular damage when PETCO2 is reduced by more than 30% .
Before that, the slow rise of PETCO2 should also attract enough attention .
Studies have found that even a 2mmHg change already indicates an event .

Typically , about half of patients show some form of cardiovascular damage when PETCO2 is reduced by more than 30% .
Before that, the slow rise of PETCO2 should also attract enough attention .
Studies have found that even a 2mmHg change already indicates an event .

Foamy blood aspirated through a central venous catheter is the basis for the diagnosis of air embolism
.
Other valuable tests include pulmonary artery catheter manometry, precordial Doppler ultrasonography, end-tidal volume and airway pressure monitoring, and arterial blood gas analysis
.

Foamy blood aspirated through a central venous catheter is the basis for the diagnosis of air embolism
.
Other valuable tests include pulmonary artery catheter manometry, precordial Doppler ultrasonography, end-tidal volume and airway pressure monitoring, and arterial blood gas analysis
.

emergency treatment

emergency treatment

1.
When intraoperative suspected CO2 embolism, the pneumoperitoneum pressure should be reduced first or the pneumoperitoneum should be relieved immediately
.

1.
When intraoperative suspected CO2 embolism, the pneumoperitoneum pressure should be reduced first or the pneumoperitoneum should be relieved immediately
.

2.
Adjust the body position to the left lateral decubitus position, so that the gas is far away from the pulmonary artery orifice at the vertex of the right ventricle
.

2.
Adjust the body position to the left lateral decubitus position, so that the gas is far away from the pulmonary artery orifice at the vertex of the right ventricle
.

3.
Inhalation of 100% pure oxygen can remove CO2 and improve hypoxemia
.

3.
Inhalation of 100% pure oxygen can remove CO2 and improve hypoxemia
.

4.
Increasing the central venous pressure can reduce the continuous entry of CO2 , prevent the bubble volume from further increasing, and extract the gas from the superior vena cava if necessary
.

4.
Increasing the central venous pressure can reduce the continuous entry of CO2 , prevent the bubble volume from further increasing, and extract the gas from the superior vena cava if necessary
.

5.
For more serious CO2 embolism, because of the large air bubbles in the circulatory system, immediately perform chest compression on the patient
.
Effective chest compression can crush larger air bubbles in the blood and turn them into smaller air bubbles, which not only relieves the " air lock " effect, but also facilitates the dissolution and absorption of CO2 .

5.
For more serious CO2 embolism, because of the large air bubbles in the circulatory system, immediately perform chest compression on the patient
.
Effective chest compression can crush larger air bubbles in the blood and turn them into smaller air bubbles, which not only relieves the " air lock " effect, but also facilitates the dissolution and absorption of CO2 .

6.
For severe CO2 embolism cases requiring cardiopulmonary resuscitation , physical cooling of the head of the ice cap should be given to reduce oxygen consumption in the brain and prevent brain damage.
It is recommended to transfer to the ICU ward for supportive treatment after surgery .

6.
For severe CO2 embolism cases requiring cardiopulmonary resuscitation , physical cooling of the head of the ice cap should be given to reduce oxygen consumption in the brain and prevent brain damage.
It is recommended to transfer to the ICU ward for supportive treatment after surgery .

Prevention key

Prevention key prevention

1.
Carefully evaluate the operations and examinations that may cause gas embolism before operation, and fully understand the patient's medical history, physical examination and various examinations
.
Communicate closely with the surgeon, jointly designate the operation and anesthesia plan, make comprehensive preparations, and improve various testing measures
.

1.
Carefully evaluate the operations and examinations that may cause gas embolism before operation, and fully understand the patient's medical history, physical examination and various examinations
.
Communicate closely with the surgeon, jointly designate the operation and anesthesia plan, make comprehensive preparations, and improve various testing measures
.

2.
Carefully check the pipeline before infusion and extracorporeal circulation, and exhaust the air in the pipeline to ensure that the pipeline is intact and not damaged, and the connection is tight
.

2.
Carefully check the pipeline before infusion and extracorporeal circulation, and exhaust the air in the pipeline to ensure that the pipeline is intact and not damaged, and the connection is tight
.

3.
Pay attention to monitoring CVP to prevent CVP from being too low
.

3.
Pay attention to monitoring CVP to prevent CVP from being too low
.

4.
Reduce the pneumoperitoneum pressure and set the appropriate PEEP to reduce the entry of CO2 .

4.
Reduce the pneumoperitoneum pressure and set the appropriate PEEP to reduce the entry of CO2 .

5.
Intraoperative close monitoring.
The study found that most cases of embolism occurred during some key operations, such as stripping the blood supply rich tissue, breaking the lacunar ligament and so on
.
At this time, the anesthesiologist must be vigilant, pay close attention to vital signs, monitor arterial blood gas in a timely manner when abnormality is found, and use TEE to identify if necessary
.

5.
Intraoperative close monitoring.
The study found that most cases of embolism occurred during some key operations, such as stripping the blood supply rich tissue, breaking the lacunar ligament and so on
.
At this time, the anesthesiologist must be vigilant, pay close attention to vital signs, monitor arterial blood gas in a timely manner when abnormality is found, and use TEE to identify if necessary
.

6.
Fine operation and careful identification to avoid bleeding.
If the suspicious cavity cannot be identified during the operation, the pneumoperitoneum can be stopped to observe whether there is foamy blood .

6.
Fine operation and careful identification to avoid bleeding.
If the suspicious cavity cannot be identified during the operation, the pneumoperitoneum can be stopped to observe whether there is foamy blood .

7.
Pay attention to the patient's position and avoid the operation site being in a high position for a long time
.

7.
Pay attention to the patient's position and avoid the operation site being in a high position for a long time
.

references:

references:

[1]Vascular Air Embolism and Endoscopy: Every Bubble Matters.
[J].
Anesthesia & Analgesia, 2018,127(2).
[2] Liu Dingsheng , Zhang Hong .
Pay attention to carbon dioxide embolism in transanal total mesorectal excision [J] .
Chinese Journal of Gastrointestinal Surgery , 2019, 22(12):5.
[3]Carbon Dioxide Embolism Associated With Total Mesorectal Excision Surgery: A Report From the International Registries.
[J].
DISEASES OF THE COLON & RECTUM VOLUME 62: 7 (2019)

[1]Vascular Air Embolism and Endoscopy: Every Bubble Matters.
[J].
Anesthesia & Analgesia, 2018,127(2).
[2] Liu Dingsheng , Zhang Hong .
Pay attention to carbon dioxide embolism in transanal total mesorectal excision [J] .
Chinese Journal of Gastrointestinal Surgery , 2019, 22(12):5.
[3]Carbon Dioxide Embolism Associated With Total Mesorectal Excision Surgery: A Report From the International Registries.
[J].
DISEASES OF THE COLON & RECTUM VOLUME 62: 7 (2019)

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