Hospitals are commonly thought of as the safest place to be for sick people.

Patients have around-the-clock access to skilled care teams. Their vital signs are continuously monitored. A physician stops by every morning to check on them.

While it all sounds safe, a hospital can be a very dangerous place to be. Here are four frightening risks hospitals pose, along with their causes and some easy-to-implement solutions that could save hundreds of thousands of lives each year:

1. Hospital stays may cause psychological harm. Hospitals are intended to maximize the health of sick people. But the ways that hospitals are designed can severely disorient patients.

Beaming florescent lights, beeping machines and loud hallway conversations disrupt natural sleep patterns. Patients are routinely awakened at night for status checks and early in the morning for blood draws. Food is withheld while doctors await tests – and is often unappealing whenever it’s served.

The combination of sleep deprivation, poor nourishment and sedative medications can produce progressive deterioration in a patient’s mental status.

Each year, 20 percent of elderly patients in hospitals develop delirium and 1 of 6 die as a result.

2. Hospital stays can lead to physical harm. The risk of physical harm runs through even the safest hospitals as patients are given powerful narcotics or sedatives, which cause confusion and make it difficult for them to walk safely. One study found patients who fell during their hospital stay were nearly three times more likely to have received a sedative.

Meanwhile, individuals on mandated bed rest face the risks of significant muscle weakness, even among the youngest and healthiest patients. Lack of regular physical activity during bed rest increases the risk of bone fractures, stiffened joints and, in some cases, contractures (where stiff joints become permanently bent).

But not all physical risks are external. Germs that can cause serious infectious diseases are prevalent in hospital environments. Worse, they often prove to be resistant to even the most potent antibiotics.

3. Hospital stays increase the risk of avoidable conditions. Over a decade ago, the Institute of Medicine reported that up to 98,000 people a year die in hospitals because of medical error. These deaths can occur from the wrong patient receiving a medication, a patient receiving the wrong medication or a miscalculated dose.

This alarming statistic did not include the patients who experienced other complications as a result of their hospital care. Such complications may include developing a pressure ulcer, falling on the way to the bathroom, or acquiring a systemic infection through an intravenous line. These kinds of complications affect as many as 4 to 5 percent of all hospitalized patients.

Yet one of the more common medical errors is also one of the most avoidable. Patients who transmit infections to others in a hospital may do so as a result of doctors, nurses and other hospital staff failing to wash their hands.

This can result in the spreading of the bacterium Clostridium difficile or “C-diff,” which can produce severe abdominal symptoms and diarrhea, damage the bowel itself, require surgery and even result in death.

Alarmingly, C-diff can contaminate surfaces in hospitals and remain infectious for up to six months. This makes sterilization of hands, rooms and hospital surfaces an absolute necessity. Over the past decade, the incidence of this problem has doubled and 1 of 14 infected patients die as a result.

4. Hospital stays sometimes result in problems after discharge. Many patients suffer ongoing physical and mental ills after discharge with some unable to regain their prior mental acuity or muscle strength.

This is most severe for those who stay in the hospital for prolonged periods, particularly with complex conditions. The elderly are especially at increased risk for falls, may no longer be able to care for their own basic needs and may have difficulty managing the details of their treatment regimen.

In addition to the health issues, many patients face ongoing financial woes after hospital discharge.

When hospital-acquired complications prolong in-patient stays by days or even weeks, patients may owe large amounts of money, experience lost income from missed work and face prolonged disability.

Small changes can bring about big improvements 

While some facilities have taken major steps toward lowering or eliminating risks, the majority of hospitals are ripe for improvement. While many hospitals require complex overhauls to minimize error or change clinical practices, the following small steps could reduce patient complications, speed up their recovery and help them avoid readmission.

To reduce the risk of psychological harm, hospitals should reduce noise and illumination at night. Let patients sleep through the night unless awakening them is essential for their medical care.

Some physical risks can be confronted easily, as well. Ambulate all patients every day, even the sickest. Physical movement reduces muscle wasting, improves breathing, and decreases the incidence of confusion and delirium.

Physical and psychological risks can be tackled together by minimizing the use of sedatives and powerful pain medications, particularly among elderly patients. Physicians should consider prescribing medications with less impact on cognition and ambulation.

To reduce medical error and the spreading of germs and bacteria, hospitals should make sure all care providers wash their hands every time they enter and leave a patient’s room. Several companies are already pushing technologies that can help hospitals monitor and promote employee hand washing.

And to avoid the trauma and dislocation of a hospital stay, hospital leaders and clinicians should consider offering high quality alternatives to an in-patient stay. Such alternatives may include ambulatory, palliative and hospice care programs. In addition, when clinically appropriate, physicians can look for opportunities and offer patients the option of going home earlier in their stay, even if only the evening before.

When hospitals overlook these simple yet significant changes, they become very dangerous places to be. But the result of these changes can be as powerful as the most sophisticated technology or the most potent medications.

Full disclosure: Many of the changes described above have been implemented at Kaiser Permanente hospitals throughout Northern California. As a result, my colleagues and I have seen reductions in sepsis mortality and the incidence of pressure ulcers, delirium, and C-diff infections, along with other hospital dangers. 

Robert Pearl is a physician and CEO, The Permanente Medical Group. This article originally appeared on Forbes.com.