AAssessment of an Earlobe Arterialized ssessment of an Earlobe Arterialized Blood Collector for use in MicrogravityBlood Collector for use in Microgravity

Thais Russomano* Thais Russomano*  Marlise A dos Santos*  Marlise A dos Santos*

 João Castro*  João Castro*  John Whittle**  John Whittle**  Simon Evetts**  Simon Evetts**  John Ernsting**  John Ernsting**

*Microgravity Laboratory/IPCT-PUCRS, Brazil

**Aerospace Medicine Group, King´s College London, UK

There is currently no method of directly measuring arterial blood gas tensions in space.

Background

There is currently no method of directly measuring arterial blood gas tensions in space.

An alternative to direct arterial measurement is earlobe arterialized blood sampling, an accurate technique for measuring blood gas tensions, which has been in use in clinical medicine and physiology for more than 30 years (Lilienthal JL & Riley RL, 1944).

Background

There is currently no method of directly measuring arterial blood gas tensions in space.

An alternative to direct arterial measurement is earlobe arterialized blood sampling, an accurate technique for measuring blood gas tensions, which has been in use in clinical medicine and physiology for more than 30 years (Lilienthal JL & Riley RL, 1944).

This technique has not yet been examined in the microgravity environment due to the risk of environmental contamination with blood products.

Background

The aim of the project is to develop a device and associated procedures that enable an acceptable estimation of arterial blood gas tensions and pH to be conducted accurately and safely in microgravity.

Aim

Introduction

Earlobe Blood Sampling – The Technique

Introduction

Earlobe Blood Sampling – The Technique The earlobe is rendered hyperemic by the application of a rubefacient cream containing 1% methyl nicotinate.

Introduction

Earlobe Blood Sampling – The Technique The earlobe is rendered hyperemic by the application of a rubefacient cream containing 1% methyl nicotinate.

The skin is then cleaned with an alcohol swab and a small incision is made in the earlobe.

Introduction

Earlobe Blood Sampling – The Technique The earlobe is rendered hyperemic by the application of a rubefacient cream containing 1% methyl nicotinate.

The skin is then cleaned with an alcohol swab and a small incision is made in the earlobe.

Blood is collected anaerobically via capillary tubes.

Introduction

Earlobe Blood Sampling – The Technique The earlobe is rendered hyperemic by the application of a rubefacient cream containing 1% methyl nicotinate.

The skin is then cleaned with an alcohol swab and a small incision is made in the earlobe.

Blood is collected anaerobically via capillary tubes.

Blood is then analyzed using a blood gas analyzer.

Introduction

Earlobe massage

Earlobe arterialized blood collection

Characteristic Radial Artery Sample

Hyperemic Earlobe Sample

Discomfort Painful Pain Free

Potential Complications

Hematoma Hemorrhage

Infection (systemic) Wrist pain

Arterial Spasm

Hemorrhage Infection (cutaneous)

Ease of Use Requires trained medical personnel

Performed by non-medical personnel.

Potential Usage Hospital based research

Hospital, clinic, rural center and university research.Aero medical and transport use. ISS and other space missions.

Radial Artery / Arterialised Earlobe Collection

Characteristic Radial Artery Sample

Hyperemic Earlobe Sample

Discomfort Painful Pain Free

Potential Complications

Hematoma Hemorrhage

Infection (systemic) Wrist pain

Arterial Spasm

Hemorrhage Infection (cutaneous)

Ease of Use Requires trained medical personnel

Performed by non-medical personnel.

Potential Usage Hospital based research

Hospital, clinic, rural center and university research.Aero medical and transport use. ISS and other space missions.

Characteristic Radial Artery Sample

Hyperemic Earlobe Sample

Discomfort Painful Pain Free

Potential Complications

Hematoma Hemorrhage

Infection (systemic) Wrist pain

Arterial Spasm

Hemorrhage Infection (cutaneous)

Ease of Use Requires trained medical personnel

Performed by non-medical personnel.

Potential Usage Hospital based research

Hospital, clinic, rural center and university research.Aero medical and transport use. ISS and other space missions.

Characteristic Radial Artery Sample

Hyperemic Earlobe Sample

Discomfort Painful Pain Free

Potential Complications

Hematoma Hemorrhage

Infection (systemic) Wrist pain

Arterial Spasm

Hemorrhage Infection (cutaneous)

Ease of Use Requires trained medical personnel

Performed by non-medical personnel.

Potential Usage Hospital based research

Hospital, clinic, rural center and university research.Aero medical and transport use. ISS and other space missions.

Characteristic Radial Artery Sample

Hyperemic Earlobe Sample

Discomfort Painful Pain Free

Potential Complications

Hematoma Hemorrhage

Infection (systemic) Wrist pain

Arterial Spasm

Hemorrhage Infection (cutaneous)

Ease of Use Requires trained medical personnel

Performed by non-medical personnel.

Potential Usage Hospital based research

Hospital, clinic, rural center and university research.Aero medical and transport use. ISS and other space missions.

Development and Evaluation of a Earlobe Arterialized Blood Collector

Prototype of the Earlobe Arterialized Blood (EAB) Collector

Current Prototype of the EAB Collector

Blade module

Capillary tube module

Capillary tube

Body (module housing)

Ophthalmic blade

A validation study of the EAB Collector was conducted in which simultaneous samples of arterial and arterialized blood were taken from the radial artery and the earlobe.

Method

A validation study of the EAB Collector was conducted in which simultaneous samples of arterial and arterialized blood were taken from the radial artery and the earlobe.

Six healthy subjects breathed a gas mixture of 12.8% O2 in N2 (equivalent to breathing air at 12,000 feet) during 15 min of head-down tilt.

Method

A validation study of the EAB Collector was conducted in which simultaneous samples of arterial and arterialized blood were taken from the radial artery and the earlobe.

Six healthy subjects breathed a gas mixture of 12.8% O2 in N2 (equivalent to breathing air at 12,000 feet) during 15 min of head-down tilt.

The blood samples were analyzed immediately.

Method

MethodHead Down Tilt to partially replicate the

effects of microgravity

Results

Blood Gas Data for Simultaneous Radial Artery and Earlobe Arterialized Blood Samples  

  Radial arteryMean SD (range)

Arterialized EarlobeMean SD (range)

pH(pH Unit)

7.43 0.02 (7.4 – 7.46) 7.43 0.02 (7.4 – 7.46)

PO2

(mmHg)

42.1 3.66 (38 – 47) 42.9 3.88 (37 – 50)

PCO2

(mmHg)

34.1 1.88 (31 – 37) 33.12 2.38 (29 – 37)

SaO2

(%)

79.0 3.85 (75 – 84.5) 79.9 3.29 (74 –85.6)

Results

Blood Gas Data for Simultaneous Radial Artery and Earlobe Arterialized Blood Samples  

  Radial arteryMean SD (range)

Arterialized EarlobeMean SD (range)

pH(pH Unit)

7.43 0.02 (7.4 – 7.46) 7.43 0.02 (7.4 – 7.46)

PO2

(mmHg)

42.1 3.66 (38 – 47) 42.9 3.88 (37 – 50)

PCO2

(mmHg)

34.1 1.88 (31 – 37) 33.12 2.38 (29 – 37)

SaO2

(%)

79.0 3.85 (75 – 84.5) 79.9 3.29 (74 –85.6)

Results

Blood Gas Data for Simultaneous Radial Artery and Earlobe Arterialized Blood Samples  

  Radial arteryMean SD (range)

Arterialized EarlobeMean SD (range)

pH(pH Unit)

7.43 0.02 (7.4 – 7.46) 7.43 0.02 (7.4 – 7.46)

PO2

(mmHg)

42.1 3.66 (38 – 47) 42.9 3.88 (37 – 50)

PCO2

(mmHg)

34.1 1.88 (31 – 37) 33.12 2.38 (29 – 37)

SaO2

(%)

79.0 3.85 (75 – 84.5) 79.9 3.29 (74 –85.6)

Results

Blood Gas Data for Simultaneous Radial Artery and Earlobe Arterialized Blood Samples  

  Radial arteryMean SD (range)

Arterialized EarlobeMean SD (range)

pH(pH Unit)

7.43 0.02 (7.4 – 7.46) 7.43 0.02 (7.4 – 7.46)

PO2

(mmHg)

42.1 3.66 (38 – 47) 42.9 3.88 (37 – 50)

PCO2

(mmHg)

34.1 1.88 (31 – 37) 33.12 2.38 (29 – 37)

SaO2

(%)

79.0 3.85 (75 – 84.5) 79.9 3.29 (74 –85.6)

Results

Blood Gas Data for Simultaneous Radial Artery and Earlobe Arterialized Blood Samples  

  Radial arteryMean SD (range)

Arterialized EarlobeMean SD (range)

pH(pH Unit)

7.43 0.02 (7.4 – 7.46) 7.43 0.02 (7.4 – 7.46)

PO2

(mmHg)

42.1 3.66 (38 – 47) 42.9 3.88 (37 – 50)

PCO2

(mmHg)

34.1 1.88 (31 – 37) 33.12 2.38 (29 – 37)

SaO2

(%)

79.0 3.85 (75 – 84.5) 79.9 3.29 (74 –85.6)

Results

The mean difference in PO2 between arterialized earlobe and arterial samples was 0.25 ( ± 1.25) mmHg.

Results

The mean difference in PO2 between arterialized earlobe and arterial samples was 0.25 ( ± 1.25) mmHg.

Comparison of PCO2 of the arterialized earlobe and arterial samples showed a mean difference of -1 ( ± 0.75) mmHg.

Results

The mean difference in PO2 between arterialized earlobe and arterial samples was 0.25 ( ± 1.25) mmHg.

Comparison of PCO2 of the arterialized earlobe and arterial samples showed a mean difference of -1 ( ± 0.75) mmHg.

There was no difference between the pH values of the arterialized earlobe and arterial samples.

Correlations between Arterial and Earlobe Blood Sample Measurements

r = 0.93 r = 0.94

r = 0.97 r = 0.92

Discussion

 

 

 

Arterilaized Capillary- Arterial Mean ( SD)

PO2

mmHg

PCO2

mmHg  Langlands & Wallace

(1965) (n=16)

 

0.62(4.1)

 

 

1.05(1.6)

 

Godfrey et al. (1971) (n=8) 

2.09(2.48)

 

 

0.65(1.2)

 

Spiro & Dowdeswell (1971) (n=11) 

-0.72(1.67)

 

 

1.0(1.91)

 

Dar et al. (1995) (n=55) 

 

0.675(4.43)

 

 

0.75(2.25)

 

Present study (n=6) 

 

0.25(1.25)

 

-1.0(0.75)

Study Author

Discussion

 

 

 

Arterilaized Capillary- Arterial Mean ( SD)

PO2

mmHg

PCO2

mmHg  Langlands & Wallace

(1965) (n=16)

 

0.62(4.1)

 

 

1.05(1.6)

 

Godfrey et al. (1971) (n=8) 

2.09(2.48)

 

 

0.65(1.2)

 

Spiro & Dowdeswell (1971) (n=11) 

-0.72(1.67)

 

 

1.0(1.91)

 

Dar et al. (1995) (n=55) 

 

0.675(4.43)

 

 

0.75(2.25)

 

Present study (n=6) 

 

0.25(1.25)

 

-1.0(0.75)

Study Author

Discussion

 

 

 

Arterilaized Capillary- Arterial Mean ( SD)

PO2

mmHg

PCO2

mmHg  Langlands & Wallace

(1965) (n=16)

 

0.62(4.1)

 

 

1.05(1.6)

 

Godfrey et al. (1971) (n=8) 

2.09(2.48)

 

 

0.65(1.2)

 

Spiro & Dowdeswell (1971) (n=11) 

-0.72(1.67)

 

 

1.0(1.91)

 

Dar et al. (1995) (n=55) 

 

0.675(4.43)

 

 

0.75(2.25)

 

Present study (n=6) 

 

0.25(1.25)

 

-1.0(0.75)

Study Author

Discussion

 

 

 

Arterilaized Capillary- Arterial Mean ( SD)

PO2

mmHg

PCO2

mmHg  Langlands & Wallace

(1965) (n=16)

 

0.62(4.1)

 

 

1.05(1.6)

 

Godfrey et al. (1971) (n=8) 

2.09(2.48)

 

 

0.65(1.2)

 

Spiro & Dowdeswell (1971) (n=11) 

-0.72(1.67)

 

 

1.0(1.91)

 

Dar et al. (1995) (n=55) 

 

0.675(4.43)

 

 

0.75(2.25)

 

Present study (n=6) 

 

0.25(1.25)

 

-1.0(0.75)

Study Author

Discussion

 

 

 

Arterilaized Capillary- Arterial Mean ( SD)

PO2

mmHg

PCO2

mmHg  Langlands & Wallace

(1965) (n=16)

 

0.62(4.1)

 

 

1.05(1.6)

 

Godfrey et al. (1971) (n=8) 

2.09(2.48)

 

 

0.65(1.2)

 

Spiro & Dowdeswell (1971) (n=11)

 

-0.72(1.67)

 

 

1.0(1.91)

 

Dar et al. (1995) (n=55) 

 

0.675(4.43)

 

 

0.75(2.25)

 

Present study (n=6) 

 

0.25(1.25)

 

-1.0(0.75)

Study Author

Discussion

 

 

 

Arterilaized Capillary- Arterial Mean ( SD)

PO2

mmHg

PCO2

mmHg  Langlands & Wallace

(1965) (n=16)

 

0.62(4.1)

 

 

1.05(1.6)

 

Godfrey et al. (1971) (n=8) 

2.09(2.48)

 

 

0.65(1.2)

 

Spiro & Dowdeswell (1971) (n=11) 

-0.72(1.67)

 

 

1.0(1.91)

 

Dar et al. (1995) (n=55) 

 

0.675(4.43)

 

 

0.75(2.25)

 

Present study (n=6) 

 

0.25(1.25)

 

-1.0(0.75)

Study Author

Discussion

Points of note.

Discussion

Points of note.

• Arterialized blood collection from the earlobe is virtually pain free.

Discussion

Points of note.

• Arterialized blood collection from the earlobe is virtually pain free.

• Anaesthetic is not required.

Discussion

Points of note.

• Arterialized blood collection from the earlobe is virtually pain free.

• Anaesthetic is not required.

• Anaerobic blood collection is possible.

Discussion

Points of note.

• Arterialized blood collection from the earlobe is virtually pain free.

• Anaesthetic is not required.

• Anaerobic blood collection is possible.

• EAB Collector prevents environmental contamination.

Conclusion

This limited study suggests that:

Conclusion

This limited study suggests that:

1. Arterialized blood sampled from the earlobe provides accurate estimations of arterial blood measurements of PO2, PCO2 and pH during microgravity simulation and in hypoxia.

Conclusion

This limited study suggests that:

1. Arterialized blood sampled from the earlobe provides accurate estimations of arterial blood measurements of PO2, PCO2 and pH during microgravity simulation and in hypoxia.

2. Blood collection will be possible in microgravity without environmental contamination.

Further Studies

1. To validate the EAB Collector during normoxia in other body positions (sitting and supine);

2. To test the efficiency of the EAB Collector in microgravity (parabolic flight).*

* Protocol under evaluation by ESA.

Thank you for listening

Questions?

Professor Thais Russomano

russomano@pro.via-rs.com.bror

trussomano@hotmail.com

Results

Individual Data