garments and Kylee mobile application in the second quarter, culminating in the full market release of both products in July.”
Mr. Reuvers continued, “Our updated 2022 total revenue guidance now reflects the stronger-than-expected revenue results in the first six months of 2022 and our updated growth expectations for the balance of the year. In the second half of 2022, we are focused on improving the productivity of recently hired and promoted sales representatives, furthering the successful introduction of our new products and supporting our AffloVest channel partners, and positioning ourselves for improved profitability.”
Second Quarter 2022 Financial Results
Total revenue in the second quarter of 2022 increased $8.6 million, or 17%, to $59.6 million, compared to $51.1 million in the second quarter of 2021. The increase in total revenue was attributable to $8.0 million in sales of the airway clearance product line, which includes the AffloVest product acquired on September 8, 2021, and an increase of $0.6 million, or 1%, in sales and rentals of the lymphedema product line in the quarter ended June 30, 2022, compared to the second quarter of 2021.
Gross profit in the second quarter of 2022 increased $7.0 million, or 19%, to $43.2 million, compared to $36.2 million in the second quarter of 2021. Gross margin was 72.5% of revenue, compared to 70.9% of revenue in the second quarter of 2021. Non-GAAP gross margin was 73.0% of revenue, compared to 70.9% of revenue in the second quarter of 2021.
Operating expenses in the second quarter of 2022 increased $11.0 million, or 30%, to $47.3 million, compared to $36.3 million in the second quarter of 2021.
Operating loss was $4.1 million in the second quarter of 2022, compared to $0.1 million in the second quarter of 2021. Non-GAAP operating loss in the second quarter of 2022 was $1.8 million, compared to non-GAAP operating income of $0.9 million in the second quarter of 2021.
Other expense was $0.6 million in the second quarter of 2022, compared to $24,000 in the second quarter of 2021. The change in other expense was primarily due to an increase in interest expense.
Income tax benefit was $20,000 in the second quarter of 2022, compared to $1.4 million in the second quarter of 2021. The difference is related to a full valuation allowance being recorded against all deferred tax assets in the current year period and a tax benefit related to a research and development credit recognized in the second quarter of 2021.
Net loss in the second quarter of 2022 was $4.6 million, or $0.23 per diluted share, compared to net income of $1.3 million, or $0.07 per diluted share, in the second quarter of 2021. Non-GAAP net loss in the second quarter of 2022 was $2.9 million, compared to non-GAAP net income $2.0 million in the second quarter of 2021.
Weighted average shares used to compute diluted net loss/income per share were 20.0 million in each of the second quarters of 2022 and 2021.
Adjusted EBITDA was $1.7 million in the second quarter of 2022, compared to $4.1 million in the second quarter of 2021.