Through-the-Wall Blood Sampling Method to Minimize Sleep Disruption in Clinical Settings

We study how sleep and circadian rhythms impair cardiometabolic health. Ultimately, we would like to find strategies to reduce the rest of diseases associated with sleep and circadian disruption. To study things that change in the body over 24 hours, we need to have a window into the system during the entire period.

This can be tough because we don't want to disturb sleep in circadian rhythms by going into a participant's room while they're sleeping to get a blood sampling. To get around that, we use a through the wall blood sampling protocol. We address the gap by using a long IV line that we place through the wall from which we can sample blood from outside the participant room.

This allows us to sample blood with minimal disruption to sleep and circadian rhythms. Our findings will allow researchers to access metabolic health markers such as glucose and insulin across 24 hours without disturbing sleep, which can help clarify the influence of sleep and circadian rhythms on disease risk. To begin, attach the extension line for through the wall sampling by connecting the three-way stop to the female lure lock end of the extension line.

After breaking the seals, place the 10 milliliter saline flush syringe and the three milliliter sample syringe onto the stop cock. Twist the off tab of the stop cock to close the extension line to the three milliliter syringe and open it to the 10 milliliter saline flush. Push saline through the extension line until it reaches the end.

Carefully remove the cap and allow the saline to drip into a cup or onto the absorbent pad. Twist the off tab to close the extension line to both syringes, keeping them attached to the stop cock. Feed the capped end of the extension line through the wall port into the participant room, ensuring the cap remains in place to maintain sterility.

In the participant's room, clean the distal end of the extension line and the attachment side of the IV extension set. Using a sterile alcohol prep pad, remove the cap from the extension line and attach it to the IV extension set connected to the participant. Now return to the anti chamber.

Remove and discard the used saline flush from the stop cock and attach a warmed 10 milliliter saline flush. Twist the off tab to close the line to the sample syringe and open it to the new saline flush. Push saline through the extension line to verify the absence of leaks and confirm that the IV line remains patent.

Slowly continue pushing the saline flush while simultaneously turning the off tab to fully seal the system. Once the extension line is confirmed to be functioning, return to the participant's room to wrap the IV extension set with a self adherent elastic bandage to prevent dislodgement during sleep. Tape the extension line securely to the bed frame.

Attach afive milliliter waste syringe ensuring that the extension line is saline primed and connect a three milliliter sample syringe to the stop cock. Twist the off tab to open the line to the five milliliter waste syringe. Using the five milliliter syringe, collect at least 4.4 milliliters of waste.

Then continue drawing until whole blood appears. Now twist the off tab of the stop to close the line to the five milliliter waste syringe. Use the three milliliter syringe to draw the desired amount of blood and twist the off tab to close the extension line to both syringes.

Remove the five milliliter waste syringe and replace it with a warm 10 milliliter saline flush. Twist the off tab to close the line to the three milliliter sample syringe. Opening it to the saline flush.

Push up to 10 milliliters of warm saline into the extension line, ensuring no blood remains in the line. Remove the blood filled sample syringe for further processing and replace it with an empty three milliliter syringe. Twist the off tab to close the line to both syringes.

Slowly continue to push the saline flush while turning the off tab to maintain pressure in the extension line and minimize blood back flow. Use any remaining saline to flush through the stopcock into the empty three milliliter syringe. Then remove the saline syringe and pull back on the three milliliter syringe to extract any remaining liquid from the stop cock.

Replace all syringes to prepare for the next blood draw. The 24 hour plasma melatonin concentration profile of a participant was measured under dim light conditions. The findings suggest that the melatonin levels follow a distinct rise and fall pattern consistent with a normal circadian rhythm, confirming that the through the wall blood sampling method accurately captures hormonal changes during the biological night.

In a recent study, the success rate for through the wall blood sampling was 67%corresponding to 304 out of 454 total blood draw attempts, unsuccessful blood draws accounted for 33%attempts with 94%of these failures attributed to positional issues such as the participant lying on or occluding the extension line. During an easy blood draw, polysomnography recordings showed stable electroencephalogram, electrogram, electromyogram, and electrocardiogram signals with no evidence of arousal or sleep stage change. A difficult blood draw was associated with disrupted electroencephalogram, electrogram, and electromyogram activity along with an elevated heart rate indicative of arousal.