Yet another way to clear water drops from ETCO2 sampling line.

Sir,

It is very common to see the alarm in monitor, “sample line obstruction” especially in prolonged surgeries. It is always wise to check for a kinking of sampling line first and solve other common problem like obstruction due to water droplets. There are different ways to overcome such problem viz, using auxillary oxygen[1] or compressed air to clean sampling line, prophylactically putting HME filters.[2]

The most common thing anesthesiologist does is changing the sampling line. Many a times additional sampling line is not available. In such situation cleaning the sampling line is done by using auxiliary oxygen supply with added disadvantage of diluting anesthetic gases. Even though this method is effective, many anesthesia workstations are not having facility of auxiliary oxygen supply. In such condition, this method will help to clear water droplets.

In this method, the angle connector with side port is attached to common gas outlet as shown in Figure 1. The proximal end of sampling line is connected to side port simultaneously obstructing the open end of angle connector. The switch is turned from circle system to the open system. The fresh gas flow is increased to a total of 6-7 L/min to clear water droplets. Once cleared, the proximal end of sampling line is attached to ETCO2 module; by switching the knob to circle system the fresh gas flow is reduced to initial setting. This method helps during head and neck surgeries also where the distal end of sampling line is not approachable. One should not forget to switch back to the circle system at the end of cleaning sampling line.

Figure 1

Attachment of angle connector and sampling line to common gas outlet

Sampling line can be cleaned using this method effectively at the end of the case by oxygen flush instead of fresh gas flow.