The monitor is ringing? Dont worry. These are "false alarms".

The monitor is ringing? Don't worry. These are "false alarms".

Is the alarm alert ringing, the screen red yellow flashing, urgent processing? Comrades are slow and guardianship is also misleading. The ECG, blood pressure, blood oxygen monitoring three parts, there may be false positives, need to be specific analysis of the specific situation.

Electrocardiographic monitoring

1. P wave, T wave is higher, or QRS wave is shorter, ECG monitoring can misjudge P or T wave as QRS wave, showing double heart rate. For example, the heart rate of the original 80 times / minute was 160 times / minute, and was judged to be "supraventricular tachycardia". At this point, switching to a higher R lead can usually be solved.

2. In atrial fibrillation, if encounter a long R-R interval of 1.5s-2s, ECG monitoring shows that the heart rate slows down to 30 beats/min, triggering bradycardia alarm. However, a long RR interval of 1.5-2 s in atrial fibrillation, especially at night, is normal, does not suggest atrioventricular block and does not require special treatment. Studies have found that 99% of patients with atrial fibrillation, Holter results indicate a long RR interval of 1.5s.

3. monitor failure, or EMG interference, can appear like ventricular tachycardia, ventricular flutter and ventricular fibrillation. Here are two recent examples.

Case 1: A patient with ischemic cardiomyopathy, EF25%, was admitted to hospital with ventricular tachycardia and flutter. At dawn, the nurse noticed that the patient's monitor was sinusoidal and the doctor on duty decided that it was a "room flutter". However, she was conscious and her blood pressure was acceptable. She was ready to give amiodarone and called me. However, I refused, and room flutter and awareness were never linked. A limb-guided electrocardiogram was pulled and P-QRS-T was clearly visible. The sinusoidal wave pattern was actually caused by the failure of the monitor.Monitor manufacturers

The second case was a palpitation patient admitted to the hospital. A ventricular tachycardia wave pattern similar to tip torsion appeared on ECG telemetry at morning shift. The frequency was about 220 BPM and the sinus rhythm was restored after 10 seconds. Immediately went to the bedside to see the patient, asking whether there was no blackhead or loss of consciousness, but rather brushing teeth. Obviously, although the ECG monitoring morphology is similar, it is by no means the occurrence of ventricular tachycardia, such a fast frequency of ventricular tachycardia, the shape of "ugly" for a long time, can not be unconscious loss, which is the cause of EMG interference when brushing teeth.

4. some of the differential diagnosis of arrhythmias, ECG monitoring requirements are too high. For example, supraventricular tachycardia with bundle branch block, or supraventricular tachycardia with differential transmission, monitoring is usually reported as ventricular tachycardia. Atrial flutter is usually reported as supraventricular tachycardia. Soon sinus rhythm can also be reported as supraventricular tachycardia. At this time, we need to improve the bedside ECG to identify.Monitor manufacturers

Blood pressure monitoring

Monitoring blood pressure sometimes can not objectively reflect the patient's condition. For standard blood pressure measurements, patients should rest in a quiet, temperature appropriate environment for 5~10 minutes. The upper arm was bare, the palm of the hand was extended flat, the elbow was at the level of the heart, and the upper arm was measured at 45 degrees with the body. In fact, however, blood pressure monitoring is not always in an ideal state, and some cases have a great impact on blood pressure measurement.

For example, patients are often in recumbent position, and the blood pressure in recumbent position can be 5-10 mmHg higher than that in sitting position. For patients with orthostatic hypotension, the difference between the two can be more than 20 mmHg. Lateral decubitus is also a common body position, which can cause significant errors in blood pressure measurement. Some studies have found that the systolic pressure of the right upper limb is 10-20 mmHg lower than that of the lie-down position, and the blood pressure of the left upper limb is also lower than the actual value in the right lateral position. Active measurements (such as eating meals) or excessive flexion of the upper limbs can also lead to larger measurement errors.

In addition, atrial fibrillation rhythm, because of the pulse intensity variations, may also cause greater error in measurement results, or even blood pressure can not be measured. Since the monitoring of blood pressure measurement has many factors, in the face of obvious abnormal values should pay attention to re-test identification.

Blood oxygen monitoring

Blood oxygen saturation (SpO2) is the percentage of oxygen-bound hemoglobin oxygenate (HbO2) in the blood as a whole bound hemoglobin volume, and oxygen monitoring measures the tip of the SPO2. The principle is to use a finger-sleeve photoelectric sensor, using 660 nm red light (oxyhemoglobin absorption) and 940 nm near-infrared light (reduced hemoglobin absorption) as the light source, measuring the intensity of light transmission through the finger tissue bed to calculate hemoglobin concentration and blood oxygen saturation.

Blood perfusion at the fingertip directly affects the measurement of SpO2 at the tip of the finger. For example, in shock state (such as wall right ventricular myocardial infarction, severe infection, etc.), fingertip perfusion is poor, resulting in SpO2 values lower than the actual, or even can not be measured. Exposed fingertips, low temperature and poor perfusion are also common factors.

In addition, fingertip displacement (red light is not aligned with nail bed), abnormal fingertip color (dirt, nail polish, nail bed thickness), ipsilateral blood pressure measurement, ipsilateral infusion and exosmotic swelling, will cause SpO2 low. When the SpO2 value of the fingertip does not conform to the clinic, the other part of the measurement can be changed first. If it is still abnormal, the cause should be considered and arterial blood gas analysis should be performed.