Comparison of volume control and pressure control ventilation in patients undergoing single level anterior cervical discectomy and fusion surgery

Effects of pressure- and volume-controlled ventilation on the work of breathing in cats using a cuffed endotracheal tube

Background and Aim:

Mechanical ventilation is essential for supporting patients’ respiratory function when they are under general anesthesia. For cats with limited lung capacity, the different effects of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) on respiratory function remain elusive. The objective of the present study was to compare the efficacy of VCV and PCV in cats under general anesthesia using a cuffed endotracheal tube (ETT).

Materials and Methods:

Twelve healthy cats were randomly allocated to either a VCV or PCV group. Five tidal volumes (6, 8, 10, 12, and 14 mL/kg) were randomly applied to assess the efficacy of VCV, and respiratory rates were adjusted to achieve a minute ventilation of 100 mL/kg/min. Peak inspiratory pressures (4, 5, 6, 7, and 8 mmHg) were randomly applied to assess the efficacy of PCV, and respiratory rates were adjusted to achieve a minute ventilation of 100 mL/kg/min. Blood pressure, gas leakages, and end-tidal CO₂ were recorded from 60 trials for airway control during the use of VCV or PCV. Data were compared using Fisher’s exact test with a significance level of p<0.05.

Results:

Leakages did not differ between VCV (1/60 events) and PCV (0/60 events; p=0.500). Hypercapnia was identified when using VCV (6/60 events) less frequently than when using PCV (7/60 events; p=0.762), but did not reach statistical significance. Hypotension (mean arterial blood pressure <60 mmHg) occurred less frequently with VCV (0/60 events) than with PCV (9/60 events; p=0.003). Moreover, VCV provided a significantly lower work of breathing (151.10±65.40 cmH₂O mL) compared with PCV (187.84±89.72 cmH₂O mL; p<0.05).

Conclusion:

VCV in cats using a cuffed ETT causes less hypotension than PCV. It should be noted that VCV provides a more stable tidal volume compared with PCV, resulting in a more stable minute volume. Nonetheless, VCV should not be used in patients with an airway obstruction because higher peak airway pressure may occur and lead to lung injury.

Comparison of effects of volume-controlled and pressure-controlled mode of ventilation on endotracheal cuff pressure and respiratory mechanics in laparoscopic cholecystectomies: A randomised controlled trial

Background and Aims:

One of the pathophysiological consequences of pneumoperitoneum is variations in endotracheal cuff pressure (ETTc). Volume-controlled mode and pressure-controlled mode of ventilation being two modes of ventilatory strategies; we intended to find out variations in ETTc governed by respiratory mechanics between these two modes during laparoscopic cholecystectomies.

Methods:

After obtaining ethics committee approval, this randomised (1:1), active-controlled, parallel-assigned study was done on 60 patients undergoing laparoscopic cholecystectomies. These patients were allocated into two groups by computer-generated randomisation: Volume-controlled mode (V) and pressure-controlled mode (P). We observed for variations in ETTc which was the primary aim and haemodynamic parameters; respiratory mechanics at baseline (T1), at pneumoperitoneum (T2), after 10 min (T3), 20 min (T4) of pneumoperitoneum and at desufflation (T5). Post-operative laryngotracheal co-morbidities were also observed. Analysis was done using Statistical Package for the Social Sciences version 16.0 (IBM SPSS Statistics, Somers NY, USA).

Results:

No statistically significant difference was found in both groups either concerning ETTc, haemodynamic parameters or complications. In both groups, ETTc variation was statistically significant when compared from baseline to desufflation (T1 versus T5) and in group V additionally from baseline to time of pneumoperitoneum (T1 versus T2). Group P showed lower peak airway pressure at desufflation and higher mean airway pressure throughout at all the time intervals.

Conclusions:

There is no variation in ETTc between the two modes. Group P appears to be better in terms of lower Ppeak and better Pmean.