Wednesday, July 30, 2014

Sleep-disordered breathing in pregnancy

I've blogged before here, here, and here about pregnancy and breathing disorders in sleep. We know that the prevalence of sleep-disordered breathing (SDB) symptoms increases the further along in the pregnancy. This could be due weight gain and swelling that occurs as pregnancy progresses.

Some studies have shown an association between SDB and pregnancy-related illnesses like high blood pressure, gestational diabetes, and pre-term birth. However, many of these studies relied on subjective assessment of SDB. This study was done to look at the relationship of objectively assessed SDB and certain pregnancy-related illnesses. A home sleep study was performed on pregnant women twice - once between 6 - 20 weeks and again between 28 - 37 weeks. Results showed that 30% of the pregnant women had SDB early pregnancy. However, there was no relationship between SDB and maternal high blood pressure (called preeclampsia), preterm birth, or extremes of birthweight (low or high). There was a relationship between SDB severity and risk of developing gestational diabetes, even after controlling for confounding factors like age, race, body-mass index, hx of chronic high blood pressure, etc.

Despite the observed relationship between sleep-disordered breathing and gestational diabetes, the study authors pointed out that there is no evidence that treatment of the SDB in the short term improves maternal or neonatal outcomes.

Wednesday, July 23, 2014

What drowsy drivers do to remain alert

Driving drowsy is a big problem, and a discussion I have with my patients every day. Studies have shown that driving drowsy can be as dangerous as driving drunk. And the combination of alcohol with sleep deprivation is extremely dangerous. When I ask my patients what they do if they feel sleepy while driving, most tell me they do things that studies have shown are not helpful. Examples include rolling down the windows or turning the radio up. The first thing that I say is that if the patient feels sleepy, they should not drive or operate heavy machinery until they feel rested and wide awake. I then explain to them that if they get sleepy while driving, they should switch drivers or pull over to take a nap.

Here is a report on the top things drivers do to remain alert while driving. I got this information from a survey done by DMEautomotive. Some notable responses to what drivers do when they feel sleepy while driving include:

58% drink caffeine (not shown to be helpful)
39% open a sunroof or window (not shown to be helpful)
45% switch drivers (has been shown to be helpful IF the other driver is rested!)
23% pull over and take a nap (this is the THE most helpful thing a drowsy driver can do!)

As stated in the article, the best course of action for drowsy drivers is to pull over and take a nap. The only cure for sleepiness is more sleep! Please be safe on the road.

Wednesday, July 16, 2014

Sleep loss and psychosis

Sleep deprivation has interesting affects on our mental and physical functioning. For example, sleep deprivation tends to temporarily improve the mood of patients with depression. In fact, too little sleep can result in a manic episode in patients with bipolar disorder. This study showed that one full night of sleep depression can produce symptoms that resemble psychosis. Psychosis is a mental disorder where the person "breaks" with reality, and is part of the disorder called schizophrenia. The most common symptoms are hallucinations and delusions. The results of the study about sleep deprivation are remarkable because the psychotic symptoms occurred after only one night of sleep loss. But don't worry, the psychotic symptoms resolved completely after sleeping the next night. The researchers theorize that psychosis from sleep loss may possibly be used to study mental illness and medications used to treat mental illness.

Wednesday, July 9, 2014

Insomnia and high blood pressure

Primary insomnia means difficulty sleeping not due to another medical or sleep disorder. It's a common problem but has not been conclusively linked with increased risk of medical illness. It has been shown to increase risk of depression. Part of what I do when I treat chronic insomnia is to explain that insomnia by itself is not medically dangerous. The studies that have shown links between insomnia and medical problems have not distinguished primary from secondary insomnia. Insomnia secondary to obstructive sleep apnea (OSA) can increase risk for cardiovascular (CV) disease, but it's the OSA, not the insomnia that is raising the CV risk.

Here is an article confirming what's already known about primary insomnia and high blood pressure. The results showed no link between insomnia and high blood pressure, even for 'severe' insomnia.

Wednesday, July 2, 2014

Positional therapy for obstructive sleep apnea

A subset of my patients with obstructive sleep apnea (OSA) have it only on their back. By this, I mean that I've documented with a sleep study that a patient has OSA when sleeping on their back, but no OSA when on their sides. In my experience, this type of OSA is rare and usually only in patients with normal weight. But these patients have a treatment option that does not work in a majority of OSA patients - positional therapy. This means that if the patient can sleep on their sides or stomach only, they greatly reduce their snoring and sleep apnea. The trick is to not sleep on their back - something hard to do if they are asleep! I usually advocate using pillows behind the back to keep the person from rolling onto their side.

The FDA has just cleared an interesting device for positional OSA. It's called Night Shift by Advanced Brain Monitoring. It's a small device worn around the neck at night. It detects position (probably by gyroscope) and causes mild vibrations when the wearer is on their back. The vibrations help the user roll over, but stay asleep. The device vibrates more vigorously if the person is not responding. Their have been some studies on this device and they report improvement in sleep quality, reduction of snoring volume, and reduction of OSA.

Wednesday, June 25, 2014

Human growth hormone and sleep quality

Human growth hormone (HGH) is popular amongst some athletes who use it for performance enhancement. A significant amount of HGH is secreted at night when asleep. Sleep deprivation can reduce HGH levels. HGH levels also naturally decrease with age. HGH can be used to treat certain medical conditions, like Prader-Willi Syndrome, which can cause sleep problems. I've not seen it used however in otherwise healthy people to improve sleep quality.

This study did just that - subjects took HGH at bedtime and reported significant improvement in time to fall asleep. They also had less time awake in the middle of the night and woke more rested in the morning. No reason for why HGH may improve sleep quality is given. Perhaps scientists will discover a novel mechanism of action to help those with reduced sleep quality.

Wednesday, June 18, 2014

Sleeping pills and heart failure

Patients with heart failure are at increased risk of having sleep difficulties. Sleep-related breathing difficulties like sleep apnea are also more common in heart failure patients. Here is a study that looked at sleeping pills and heart failure patients. Specifically, the researchers investigated the relationships between drugs prescribed at hospital discharge, going back into the hospital, and cardiovascular events in heart failure patients.

The results showed that sleeping pills increase the risk of cardiovascular events in heart failure patients by 8-fold. The type of sleeping pills that were most risky were the benzodiazepines like valium. At the end of the article, the researchers speculate that benzodiazepine sleep aids could reduce cardiac function or cause respiratory depression, and this could worsen any underlying sleep-related breathing disorders. The latter is certainly possible and underscores the importance of heart failure patients getting evaluated for sleep apnea. Prior to prescribing sleep aids, it's best to rule out sleep-related breathing disorders. If sleep apnea is present, that needs to be treated, rather than just giving sleep aids.