Canadian Neighbor Pharmacy: Results of Pleural Drainage Systems

18 Jan

Surgical Products

Relation Between Flow and Negative Suction Pressure

Dry PDSs: With the exception of the Sentinel Seal (Sherwood Medical; Tullamore, Ireland), in normal suction conditions (—150 mb) all of the models reached maximum flow rates between 17 and 30 L/min (Fig 2). The Pleur-evac A-6000 (Genzyme Surgical Products Corporation; Fall River, MA) and the Atrium Oasis (Atrium Medical Corporation; Hudson, NH) are the models that achieved the highest flow rates. In almost all of the models, the increase in flow was greater when the regulator on the device was turned up from 10 to 20 L/min (range, 4 to 8 L/min), whereas little difference was seen when flow was changed from 20 to 30 L/min (range, 0 to 3 L/min), and no change was observed on shifting the regulator from 30 to 40 L/min. The Atrium Express (Atrium Medical Corporation) was the only model that increased flow by 5 to 6 L/min each time the regulator was set to a higher position. The flow in the Sentinel Seal ranged from 6 to 8 L/min with the device regulator at the same levels; although if the regulator was fully opened, a maximum flow rate of 11.5 L/min could be obtained with a negative pressure of —88 cm H2O. All news that you need at Canadian Neighbor Pharmacy website, do not waste time thinking over just follow the link and start bridening your mind.

If the wall suction level was stepped up from —150 mb to — 200 or —400 mb, the air flow rate rose substantially in all the models except for the Sentinel Seal and the Atrium Express, which hardly varied. On raising suction from —400 to — 600 mb, no increase in flow rate was observed. The Atrium Oasis and Pleur-evac A-6000 models achieved the highest flow rates (approximately 50 L/min), while the Sentinel Seal model did not reach 13 L/min despite application of a very high suction level and fully opening the regulator.

Wet PDSs: The air flow rate rose progressively according to the level of wall suction. With normal suction pressures, a flow rate of between 5 and 8 L/min and 22 and 28 L/min, respectively, was obtained- depending on whether the suction applied was —10 or —50 cm H2O (Fig 3). The air flow was usually slightly greater with the hydraulic suction level at 20 cm than with the level of 10 cm, with all of the models rising by 0.4 to 3 L/min, except for the Pleuraseal III (Rocket Medical PLC; Watford, UK), in which flow increased more (4.7 and 8.7 L/min, respectively), and the Aqua-Seal (Sherwood Medical), in which flow did not vary. If the water level is increased to 25 cm, the air flow can drop by 0.5 to 1.5 L/min because it loses water from the chamber due to the vigorous bubbling that takes place, a phenomenon that essentially appears with suction levels of —50 cm H2O. If suction pressures higher than those recommended are applied, all of the models achieve higher flow rates (range, 26 to 49 L/min).

Single-Chamber PDSs: The air flow rose progressively according to the level of wall suction. With normal suction, a flow of between 5 and 6 L/min and 24 and 27 L/min, respectively, was obtained, depending on whether the suction applied was —10 or —50 cm H2O (Fig 3). With high suction rates, flows of almost 50 L/min were reached.

Negative Pressure of the SystemNegative Pressure of the System

Dry PDSs: With a suction level of-150 mb, all the regulators on the units adjust the suction level indicated by the regulator quite accurately, with variations of ± 2 cm H2O. If the wall suction level is increased to values above those recommended by the manufacturer, the negative pressure applied with the device regulator remains fairly stable with all the models and the variation does not exceed 5 cm H2O. In the Atrium and Pleur-evac models, the pressure becomes more negative whereas with the Sentinel models the pressure becomes less negative.

The pressure regulator of the Sentinel Seal does not maintain the negative pressure steady in the presence of high suction rates when the regulator is set to -10 cm, since a loss of negative pressure of 8 cm H2O is produced. If it is set between -20 and -40 (between two and three and three quarter turns of the knob), it does maintain adequate negative pressures, but if it is opened completely it generates excessively high negative pressures (above -112.6 cm H2O).

Wet PDSs: With suction levels of -10 to -50 cm H2O, all the models are capable of adjusting the wall suction pressure to that indicated in the suction control chamber with precision (a variation of ± 2 cm H2O), provided that the wall suction level is higher than that selected on the device. The higher the wall suction level is, the more bubbling is produced in the suction control chamber. With a suction level of -10 cm, there is either no or very little bubbling, with -30 cm moderate bubbling takes place which does not lead to any loss of water in the chamber, but with -50 cm bubbling is more vigorous and can give rise loss of water if the level of the water in the chamber is 25 cm; this in turn leads to a loss of negative pressure.

When high wall suction levels are used, the flows obtained are also high but water is lost from the suction control chamber via two routes (Fig 4). On the one hand, water is sucked by the hospital vacuum source and drops of water can be seen moving along the suction tube toward the filter on the air regulator, which becomes wet. On the other hand, part of the water from the suction control chamber spills over into the water seal chamber until it is completely full. The higher the level of water in the suction control chamber is, the earlier this phenomenon will appear. If the wall suction level is increased to very high values (-600 mb) at first, the negative pressure in the device rises, but does not exceed -40 cm H2O in any models studied. Later, as the water level drops in the suction control chamber and the level of the water seal increases, negative pressure is gradually lost.

Single-Chamber PDSs: Since these PDSs have no suction regulator, the negative pressure is similar to that applied by the wall regulator. Pressure values above -112.6 cm H2O could not be determined due to the restricted scale of the spirometry equipment.

Stability of the Negative Pressure

Stability of the Negative Pressure

Dry PDSs: Depending on the position the regulator is set to, with a suction level of -150 mb the leakage gives rise to a loss of negative pressure of between 3 and 15 cm H2O in all the models except the Sentinel Seal (Fig 5). An air flow rate of 7.5 to 17.5 L/min was registered for the leakage, although in the case of the Sentinel Altitude with the regulator set at 10 or 20 the leakage rate was lower (2 to 8 L/min). In the Sentinel Seal, despite air leakage being much lower (1.7 to 6.6 L/min), the loss of negative pressure was two or three times higher than in the other models. If the wall suction level is increased to -200 mb, the leakage rises by 1 to 2 L/min and the pressures with and without leakages become somewhat more negative; negative pressure loss, however, is the same as with -150 mb. Maintaining a wall suction level of -200 mb and setting the device regulator to 40, the dry PDS (except Sentinel Seal) is capable of tolerating air leaks of 15 to 18 L/min while maintaining negative pressures of -30 cm H2O.

Wet PDSs: With a wall suction level of -30 cm H2O the leaking air flows at 3 to 15 L/min and gives rise to a loss of negative pressure of 3 to 15 cm H2O, depending on the level of water in the suction control chamber (Fig 6). If the wall suction level is increased to -40 or -50 cm H2O the air leakage rate rises by 1 to 2 L/min, but the loss of negative pressure is the same or even two or three times lower, depending on whether the water level is at 10 or 20 cm, respectively. This is due to the fact that with a higher level of suction the pressure without leakage is not modified, but the pressure with leakage does become more negative. Maintaining a wall suction level of -50 cm H2O and a device suction level of 20 cm, the wet PDS can tolerate air leaks of 10 to 12 L/min while maintaining negative pressures of-10 to -12 cm H2O.

Single-Chamber PDSs: Air leakage rate was 2 to 7 L/min and halved the negative pressure without leakage, with losses of between 6 and 24 cm H2O depending on the wall suction level (Fig 5).

Components of the Models

Compartments: The single-chamber PDSs consist in just one chamber that is used for collection and as a water seal, and has no vacuum regulator (Table 2). In wet PDSs first there is a collection chamber, the second chamber with water in it acts as a one-way system (water seal) and the third chamber, also with water in it, regulates the suction level of the unit, keeping it at 0 to -20 or -25 cm H2O. To work properly, two of their chambers must be filled with water. In dry PDSs, the water in the third chamber is replaced by a mechanical regulator that allows a higher level of suction to be achieved and can be graduated from 0 to -40 cm H2O or nongraduated (Sentinel Seal). Additionally, in the Pleur-evac Sahara and the Atrium Express, the water in the seal chamber is replaced by a one-way mechanism (valve), but it is also possible to fill this chamber with water in order to view the bubbling caused by the leak.

Accessories: Table 2 offers a detailed description of the characteristics of each PDS. Moreover, some models include other accessories. The Aqua-Seal has a wall suction inlet-outlet stopcock to allow regulation of the bubbling inside the device. It also has an auxiliary cap that can be fitted over the air vent of the suction control chamber in order to bypass this chamber and achieve a higher level of suction applied directly from the wall regulator. In the Sentinel Seal, the water seal has no graduated scale for measuring pressure and, similarly, the suction regulator is not graduated either. To make up for these limitations it is fitted with a fourth chamber, called a patient assessment chamber, which consists of a hydraulic manometer with a scale from 0 to 25 cm and which must be filled with 30 mL of water. To set a level of suction between 0 and -20 cm H2O the suction regulator is turned until the water in the fourth chamber rises to the prescribed vacuum level, while keeping the patient connecting tube closed. The Atrium Express is equipped with two short tubes in series inside the unit which impede the passage of water from one chamber to another should the device be upset.

The patient connecting tube of dry and wet PDSs (except the Pleuraseal III) is similar because they are the same compliance and the same internal diameter (10 mm). In the Pleuraseal III and single-chamber PDS the patient connecting tube has another compliance and a lower internal diameter (9 mm in the Pleuraseal III, 8 mm in the Rocket and 7 mm in the Thora-Seal). The length of patient connecting tube ranges from 181 to 220 cm depending on the models although in the case of the Rocket the length was much lower (152 cm).


Figure 2. Air flow rates obtained by dry systems. AO = Atrium Oasis; P6 = Pleur-evac A-6000; PS = Pleur-evac Sahara; AE = Atrium Express; SS = Sentinel Seal; SA = Sentinel Altitude.


Figure 3. Air flow rates obtained by wet and single-chamber systems. RC = Rocket Single chamber; TS = Thora-Seal I; OC = Atrium Ocean; P8 = Pleur-evac A-8000; P7 = Pleur-evac A-7000; PL = Pleuraseal III; AS = Aqua-Seal.


Figure 4. Disadvantage of wet systems. High level wall suction gives rise to vigorous bubbling in the suction control chamber (A) which makes water spill over into the seal chamber (B), and it is also sucked along the suction tube (D) to reach the air filter in the wall regulator. C indicates collection chamber.


Figure 5. Loss of pressure caused by an air leak. Dry systems (wall suction level set to -150 mb) and single-chamber systems (wall suction pressure at -10 to -50 cm H2O). See legends of Figures 2 and 3 for abbreviations not used in the text.


Figure 6. Loss of pressure caused by an air leak. Wet systems (wall suction level set to -30 cm H2O). See legends of Figures 2 and 3 for abbreviations not used in the text.

Table 2—Characteristics of the Different Models of PDSs

Dry systems Atrium OasisWsUD0-4029.4A + MA2,000Co,WsYesYes
Pleur-evac A-6000WsFD0-4032.1A + MA2,500WsYesYes
Pleur-evac SaharaVF + ID0-4025.3A + MA2,000Ws{YesYes
Atrium ExpressVU + ID0-4028A + MA2,100Ws{YesYes
Sentinel SealWsMD8.1A2,500NoNoNo
Sentinel AltitudeWsID0-4017.7A2,500Co,WsNoYes
Wet systems Atrium OceanWsBW0-2017.2A + MA2,100Co,Ws,SuNoYes
Pleur-evac A-8000WsBW0-2518.3A + MA2,500Co,Ws,SuNoNo
Pleur-evac A-7000WsBW0-2517.7A + MA2,500Co,Ws,SuYesYes
Pleuraseal IIIWsBW0-2516.1A + MA2,400Co,Ws,SuNoNo
Single-chamber systems Rocket Single ChamberWsNo19NoNo1,800NoNoNo
Thora-Seal IWsNo16.3NoNo2,000NoNoNo