In several situations, such as minimally invasive surgery, repeat-cardiovascular operation, pediatric cardiac surgery, and emergency cardiac resuscitation, peripheral venous cannulae are needed. Smaller venous cannulae facilitate venous cannulation.

Vacuum-assisted venous drainage (VAVD) does not rely on the height differential between the patient’s heart and the venous reservoir, unlike conventional gravity siphon venous drainage. It is possible to raise the height of the venous reservoir, shorten the venous and arterial lines, and decrease the tubing diameter. This allows remodeling of the pump console and circuit. With smaller cannulae and shorter tubing, VAVD could dramatically reduce priming volumes, maximally decrease tubing dead space, and lower patient hemodilution [8]. VAVD is becoming especially advantageous in the neonate and pediatric populations for reducing circuit size and thereby decreasing priming volume [3].

Banbury et al. [9] reported that a VAVD resulted in a smaller CPB volume (1.4  ±  0.4 l with VAVD vs. 2.0  ±  0.4 l with gravity siphon, p  <  0.0001) in valve operations. In ­neonates and infants, with use of 3/16-in. venous and arterial tubing, no arterial line filter, no prime in the venous line, and the use of VAVD, the prime volume for a neonatal circuit reportedly is as low as 200 ml [10].

Improved venous drainage reduces the fluid overload of patients. Less interstitial edema should result in better organ function and faster recovery. Reduced flow through the right atrium and less blood in the heart should reduce rewarming of the heart and contribute to improved myocardial protection [11]. It may ameliorate the inflammatory reaction caused by contact activation of neutrophils on the CPB circuit.

VAVD can provide total cardiopulmonary support with ­adequate cardiac decompression and reduce blood exposure to the damaging effects of pump suction and basket suction salvage. At the same time, VAVD can maintain higher arterial perfusion flow and higher blood levels in the venous ­reservoir, resulting in a drier, “bloodless” surgical field while also minimizing blood cell trauma [9].

Shin et al. [12] reported a case in which the huge right atrial malignant lymphoma was successfully resected using VAVD without snaring the inferior vena cava. Fukuda et al. [13] described a case of re-tricuspid valve replacement with VAVD. CPB with VAVD established before median sternotomy facilitated surgery by decompressing the heart and allowed safe reentry to the mediastinum [13]. Aklog et al. [14] performed bicaval orthotopic heart transplantation in ten patients using an open IVC anastomosis with VAVD, and they have reported good results. They stated the visualization during performance of IVC anastomosis was improved [14].

In VAVD, additional negative pressure in the venous line will augment venous blood return. An in vitro study conducted by Fiorucci et al. [15] found that the VAVD can increase venous drainage by as much as 50 %. Munster et al. [11] showed positive relationships between vacuum pressure and venous drainage and between blood temperature and venous drainage.

According to LaPietra et al. [16], negative pressure easily handled the macrobubbles and eliminated the risk of air blocks in the venous line in the event that gross air entered the venous line. VAVD permits the use of smaller caliber venous cannulae and allows the right heart chambers to be opened without the threat of venous air block.

Cardiac surgery and the use of CPB are associated with damage to end organs [5]. Roach et al. [17], in the largest prospective study on cerebral outcome after coronary artery bypass surgery, found that 6.1 % of the 2,108 patients developed serious neurological complications ranging from stroke to seizures and to deterioration of intellectual function after surgery. There is substantive evidence particularly with regard to brain injury implicating emboli as a cause of organ damage during CPB. Emboli may be gaseous, liquid, or particulate, and they may originate in the circulation or be introduced into the circulation [5].

VAVD is based on the application of a vacuum to a hard-shell venous reservoir, and it facilitates the pull of air into the venous line from around the venous cannula. Gaseous microemboli (GME) that pass through the oxygenator and arterial filter could enter the patient’s body and be responsible for neurocognitive impairment after CPB [18]. Wilcox [19] have shown that VAVD can increase entrainment of venous air with vacuum-assisted drainage and have raised safety issues concerning the system. In their study, arterial line emboli increased eight- to tenfold after the introduction of air into the venous line of a salvaged clinical adult circuit. Wang et al. [18] demonstrated that, when a fixed volume air was introduced into the venous line of a simulated neonatal CPB circuit, VAVD with higher negative pressures, increased flow rates, and pulsatile flow delivered more gaseous microemboli at the post-pump site.

Carrier et al. [20] compared the incidence of neurological complications in patient who underwent valvular surgery with and without VAVD added to standard CPB system, and they concluded that the use of VAVD during CPB in patients undergoing valve replacements does not increase the risk of significant neurological injuries. Jegger et al. [6] analyzed the vacuum pressure required to produce bubble transgression using an in vitro circuit successively including a closed reservoir, a pump (centrifugal or roller), and an oxygenator, and they stated that VAVD is a safe technique as long as the perfusionist stops the vacuum when the arterial pump is no longer in use. Wilcox [19] suggests the development of novel de-airing devices that can be incorporated safely into the perfusion circuit.

During CPB, red blood cells are damaged mainly by shear stresses, and this damage results in either immediate hemolysis, with release of free hemoglobin, or a shortened red cell life span with delayed hemolysis. This damage may potentially be increased by VAVD because of the negative pressure within the circuit and because of the turbulence generated at the tip of the smaller venous cannulae, especially when they lie in the vena cava [21].