Page 35 - ANZCP Gazette November 2021

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to Hartmann’s solution in five units (1,670 cases per year) for the unanimous reason ‘to buffer’. 50 mmol (50 mL of 8.4%) was the dosage listed by three units. The remain- ing seven (58%) Hartmann’s units did not add bicarbo- nate to their primes (2,860 cases per year).
The proportion of NaHCO3 added for Plasma-Lyte base solution was similar. A total of 20 units (43% of units; 6,445 cases) add NaHCO3 to their Plasma-Lyte base solutions, while 26 units (57% units; 9,025 cases) do not. A variety of reasons for adding bicarbonate are listed in Figure 10.
Annually, approximately 6,055 Australian patients have mannitol added to their bypass prime solutions (19
units, 30%), while 44 units (70%; 15,695 cases annually) do not add mannitol.
Most mannitol respondents (11 units) gave 10g of 20% Osmitrol, five units gave between 10 and 20g of 20% Osmitrol depending on patient factors, two units
gave 0.5 g/kg and one unit gave 0.75 mL/kg of Osmitrol. The reasons cited are listed in Figure 11.
20%
Hartmann’s
Plasma-Lyte 148
Sodium (mmol/L)
131
140
Potassium (mmol/L)
5
5
Magnesium (mmol/L)
0
1.5
Calcium (mmol/L)
2
0
Chloride (mmol/L)
112
98
Acetate (mmol/L)
0
27
Gluconate (mmol/L)
0
23
Lactate (mmol/L)
29
0
pH (range)
6.5 (5.0-7.0)
7.4 (6.5-8.0)
Osmolality (mOsm/kg)
254
271
Figure 4. Comparison of composition between Hartmann’s solution and Plasma-Lyte 148.
This survey also identified other less widely used prime additions. Five units added 1g cephazolin, one unit added an unnamed antibiotic and six units added tranexamic acid, to maintain serum levels of these drugs while on bypass. Only six units mentioned that they var- ied their prime depending on scenarios not already mentioned – diabetes, DHCA or expected long pump times.
Most units (40 units) have a standard/ institutional priming recipe for their unit. In 13 units, each perfu- sionist in the unit has their own preferred priming rec- ipe so there was no standard/ institutional priming recipe. No units in Australia routinely have the surgeon selecting the prime. One unit has the perfusionist and anaesthetist select the priming recipe. In all other units the perfusionist selects the prime.
Other general comments units listed about their primes give an interesting insight into how Australian perfusionists view their primes. Six units mentioned the importance of minimising the prime volume in their free text comments at the end of the survey; five of these centres added that minimising the prime volume was more important than what went into the prime. One other reply noted that their prime recipe was very his- torical and that literature offered little guidance other than to minimise the prime.
Discussion
This survey of priming practices highlighted a moderate degree of conformity in practice across Australian adult open-heart centres. The large response rate among Australian perfusionists indicates their interest in this topic.
All Australian adult units use balanced physiological salt solutions as a base for their priming solution. No
Figure 5. Units routinely adding albumin to prime.
• Patient factors (factors were not detailed in the response)
• Patient history (features were not detailed in the responses)
• Small patients (specific size triggers not detailed in responses)
• Older patients (>70yo and >80yo listed inresponses)
• Low patient albumin preop (<30g, <34g)
• Cases with predicted long pump times
• For very large patients to ameliorate high pressure excursions
Figure 6. Indications for adding albumin to the perfusion prime for the ‘as required’ responses.
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