Evaluation of changes in mallampati class in patients undergoing percutaneous nephrolithotomy surgeries in the prone position: A prospective observational study

Abstract Objective To evaluate airway changes in patients undergoing Percutaneous nephrolithotomy (PCNL) surgery in the prone position. Methods Modified Mallampati class (MMP) was evaluated preoperatively, and at 4, 12, 24 and 48 h postoperatively in 75 patients undergoing PCNL surgery in the prone position. The duration of surgery, amount of intravenous fluids and irrigation fluids used and estimated blood loss were evaluated for their predictive value. Results MMP class increased one class in 73.33% patients and 2 classes in 14.7%.There was no correlation between MMP change and length of surgery, amount of intravenous fluids or irrigation fluids used and surgical blood loss. The MMP reverted back to the preoperative state by 24 h in 92.4% patients and by 48 h in 4.5% patients. Conclusion MMP scores increase by at least 1 class in most of the patients after pcnl surgery in the prone position. Change in MMP class reverts back to preoperative state by 24 h in 92.4% patients and is not persistent in majority of patients at 48 h postoperatively. The degree of airway changes is unaffected by the duration of the surgery, amount of IV fluids and irrigation fluids used. Such deterioration of MMP scores in the postoperative period increases the risk of confronting difficult re -intubation, particularly in the presence of other pre-existing factors for difficult airway.