As of January this year, Aotearoa New Zealand became just the second country (after Canada) to adopt a groundbreaking new procedure for patients experiencing cardiac arrest.

Known as “double sequential external defibrillation” (DSED), it will change initial emergency response strategies and potentially improve survival rates for some patients.

Surviving cardiac arrest hinges crucially on effective resuscitation. When the heart is working normally, electrical pulses travel through its muscular walls creating regular, co-ordinated contractions.

But if normal electrical rhythms are disrupted, heartbeats can become unco-ordinated and ineffective, or cease entirely, leading to cardiac arrest.

Defibrillation is a cornerstone resuscitation method. It gives the heart a powerful electric shock to terminate the abnormal electrical activity. This allows the heart to re-establish its regular rhythm.

Its success hinges on the underlying dysfunctional heart rhythm and the proper positioning of the defibrillation pads that deliver the shock. The new procedure will provide a second option when standard positioning is not effective.

Using two defibrillators

During standard defibrillation, one pad is placed on the right side of the chest just below the collarbone. A second pad is placed below the left armpit. Shocks are given every two minutes.

Early defibrillation can dramatically improve the likelihood of surviving a cardiac arrest. However, around 20% of patients whose cardiac arrest is caused by “ventricular fibrillation” or “pulseless ventricular tachycardia” do not respond to the standard defibrillation approach. Both conditions are characterised by abnormal activity in the heart ventricles.

DSED is a novel method that provides rapid sequential shocks to the heart using two defibrillators. The pads are attached in two different locations: one on the front and side of the chest, the other on the front and back.

A single operator activates the defibrillators in sequence, with one hand moving from the first to the second. According to a recent randomised trial in Canada, this approach could more than double the chances of survival for patients with ventricular fibrillation or pulseless ventricular tachycardia who are not responding to standard shocks.

The second shock is thought to improve the chances of eliminating persistent abnormal electrical activity. It delivers more total energy to the heart, travelling along a different pathway closer to the heart’s left ventricle.

Evidence of success

New Zealand ambulance data from 2020 to 2023 identified about 1,390 people who could potentially benefit from novel defibrillation methods. This group has a current survival rate of only 14%.

Recognising the potential for DSED to dramatically improve survival for these patients, the National Ambulance Sector Clinical Working Group updated the clinical procedures and guidelines for emergency medical services personnel.

The guidelines now specify that if ventricular fibrillation or pulseless ventricular tachycardia persist after two shocks with standard defibrillation, the DSED method should be administered. Two defibrillators need to be available, and staff must be trained in the new approach.

Though the existing evidence for DSED is compelling, until recently it was based on theory and a small number of potentially biased observational studies. The Canadian trial was the first to directly compare DSED to standard treatment.

From a total of 261 patients, 30.4% treated with this strategy survived, compared to 13.3% when standard resuscitation protocols were followed.

The design of the trial minimised the risk of other factors confounding results. It provides confidence that survival improvements were due to the defibrillation approach and not regional differences in resources and training.

The study also corroborates and builds on existing theoretical and clinical scientific evidence. As the trial was stopped early due to the COVID-19 pandemic, however, the researchers could recruit fewer than half of the numbers planned for the study.

Despite these and other limitations, the international group of experts that advises on best practice for resuscitation updated its recommendations in 2023 in response to the trial results. It suggested (with caution) that emergency medical services consider DSED for patients with ventricular fibrillation or pulseless ventricular tachycardia who are not responding to standard treatment.

Training and implementation

Although the evidence is still emerging, implementation of DSED by emergency services in New Zealand has implications beyond the care of patients nationally. It is also a key step in advancing knowledge about optimal resuscitation strategies globally.

There are always concerns when translating an intervention from a controlled research environment to the relative disorder of the real world. But the balance of evidence was carefully considered before making the decision to change procedures for a group of patients who have a low likelihood of survival with current treatment.

Before using DSED, emergency medical personnel undergo mandatory education, simulation and training. Implementation is closely monitored to determine its impact.

Hospitals and emergency departments have been informed of the protocol changes and been given opportunities to ask questions and give feedback. As part of the implementation, the St John ambulance service will perform case reviews in addition to wider monitoring to ensure patient safety is prioritised.

Ultimately, those involved are optimistic this change to cardiac arrest management in New Zealand will have a positive impact on survival for affected patients.

Vinuli Withanarachchie, PhD candidate, College of Health, Massey University; Bridget Dicker, Associate Professor of Paramedicine, Auckland University of Technology, and Sarah Maessen, Research Associate, Auckland University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

No, you’re not imagining it. People really are more likely to poo in the morning, shortly after breakfast. Researchers have actually studied this.

But why mornings? What if you tend to poo later in the day? And is it worth training yourself to be a morning pooper?

To understand what makes us poo when we do, we need to consider a range of factors including our body clock, gut muscles and what we have for breakfast.

Here’s what the science says.

So morning poos are real?

In a UK study from the early 1990s, researchers asked nearly 2,000 men and women in Bristol about their bowel habits.

The most common time to poo was in the early morning. The peak time was 7-8am for men and about an hour later for women. The researchers speculated that the earlier time for men was because they woke up earlier for work.

About a decade later, a Chinese study found a similar pattern. Some 77% of the almost 2,500 participants said they did a poo in the morning.

But why the morning?

There are a few reasons. The first involves our circadian rhythm – our 24-hour internal clock that helps regulate bodily processes, such as digestion.

For healthy people, our internal clock means the muscular contractions in our colon follow a distinct rhythm.

There’s minimal activity in the night. The deeper and more restful our sleep, the fewer of these muscle contractions we have. It’s one reason why we don’t tend to poo in our sleep.

But there’s increasing activity during the day. Contractions in our colon are most active in the morning after waking up and after any meal.

One particular type of colon contraction partly controlled by our internal clock are known as “mass movements”. These are powerful contractions that push poo down to the rectum to prepare for the poo to be expelled from the body, but don’t always result in a bowel movement. In healthy people, these contractions occur a few times a day. They are more frequent in the morning than in the evening, and after meals.

Breakfast is also a trigger for us to poo. When we eat and drink our stomach stretches, which triggers the “gastrocolic reflex”. This reflex stimulates the colon to forcefully contract and can lead you to push existing poo in the colon out of the body. We know the gastrocolic reflex is strongest in the morning. So that explains why breakfast can be such a powerful trigger for a bowel motion.

Then there’s our morning coffee. This is a very powerful stimulant of contractions in the sigmoid colon (the last part of the colon before the rectum) and of the rectum itself. This leads to a bowel motion.

How important are morning poos?

Large international surveys show the vast majority of people will poo between three times a day and three times a week.

This still leaves a lot of people who don’t have regular bowel habits, are regular but poo at different frequencies, or who don’t always poo in the morning.

So if you’re healthy, it’s much more important that your bowel habits are comfortable and regular for you. Bowel motions do not have to occur once a day in the morning.

Morning poos are also not a good thing for everyone. Some people with irritable bowel syndrome feel the urgent need to poo in the morning – often several times after getting up, during and after breakfast. This can be quite distressing. It appears this early-morning rush to poo is due to overstimulation of colon contractions in the morning.

Can you train yourself to be regular?

Yes, for example, to help treat constipation using the gastrocolic reflex. Children and elderly people with constipation can use the toilet immediately after eating breakfast to relieve symptoms. And for adults with constipation, drinking coffee regularly can help stimulate the gut, particularly in the morning.

A disturbed circadian rhythm can also lead to irregular bowel motions and people more likely to poo in the evenings. So better sleep habits can not only help people get a better night’s sleep, it can help them get into a more regular bowel routine.

Regular physical activity and avoiding sitting down a lot are also important in stimulating bowel movements, particularly in people with constipation.

We know stress can contribute to irregular bowel habits. So minimising stress and focusing on relaxation can help bowel habits become more regular.

Fibre from fruits and vegetables also helps make bowel motions more regular.

Finally, ensuring adequate hydration helps minimise the chance of developing constipation, and helps make bowel motions more regular.

Monitoring your bowel habits

Most of us consider pooing in the morning to be regular. But there’s a wide variation in normal so don’t be concerned if your poos don’t follow this pattern. It’s more important your poos are comfortable and regular for you.

If there’s a major change in the regularity of your bowel habits that’s concerning you, see your GP. The reason might be as simple as a change in diet or starting a new medication.

But sometimes this can signify an important change in the health of your gut. So your GP may need to arrange further investigations, which could include blood tests or imaging.

Vincent Ho, Associate Professor and clinical academic gastroenterologist, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.