# i vs InvoSurg

The clearest difference is review sentiment: InvoSurg at 100% against i's 0%. InvoSurg also leads on rating (4.3 vs 3.4). i's advantage is update cadence (every 4 months vs every 10 months) and device support (4 vs 2). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

InvoSurg holds the better App Store score, 4.3 against 3.4. Both are backed by a comparable volume of ratings — 7 and 11 respectively. Written reviews point the same way: 0% of i's written reviews are positive against 100% of InvoSurg's.

i ships an update every 4 months, InvoSurg every 10 months. The most recent releases landed on September 21, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | i | InvoSurg |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.4 (7 ratings)](https://appshunter.io/ios/app/i-perfuse/id817922451/reviews) | **[4.3 (11 ratings)](https://appshunter.io/ios/app/invosurg/id1480250400/reviews)** |
| Number of ratings | 7 | **11** |
| Positive reviews | 0.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 months** | Every 10 months |
| Monetization | Free | Free |
| Size | 31 MB | 22 MB |
| Requires iOS | **10.0** | 14.0 |
| Devices | **iPhone, iPad, iPod, Apple Watch** | iPhone, iPod |
| Age rating | 12+ | 17+ |
| Developer | [Courtland Menke](https://appshunter.io/developer/817922454) | [Invosurg Inc.](https://appshunter.io/developer/1480250399) |

## What reviewers say

### i

[App page](https://appshunter.io/ios/app/i-perfuse/id817922451)

This medical app assists clinical perfusionists and students with cardiac surgery calculations. It offers tools for patient volume, flow rates, drug information, and quizzes. Access common equations and perfusion news within the app.

**Highlights:** Adult and Pediatric Calculators, SVR and PVR Calculator, Oxygen Delivery and Consumption Calculator, Pediatric Cannula Recommendations, Searchable Drug Database, Multiple Choice Quiz, Common Equations and Normal Values

**Features:** macOS Compatibility

**In-app purchases:** none


### InvoSurg

[App page](https://appshunter.io/ios/app/invosurg/id1480250400)

This medical app assists cardiac surgery clinicians by providing access to individualized care information, calculations for delivered oxygen during cardiopulmonary bypass, and a repository of educational events and publications. It serves as a convenient mobile reference for CPB and Extra Corporeal Life Support therapies, along with evidence-based guidelines.

**Highlights:** Individualized care information, Delivered Oxygen (DO2) calculation, Educational event calendar, CPB and ECLS therapy information, Evidence-Based Guidelines reference, Cardiac surgery publications

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is i free?

i is free to download, with no in-app purchases.

### Is InvoSurg free?

InvoSurg is free to download, with no in-app purchases.

### Which has better reviews, i or InvoSurg?

InvoSurg is rated higher. i averages 3.4 out of 5 from 7 ratings, while InvoSurg averages 4.3 from 11 ratings.

### Do i or InvoSurg have ads?

Neither i nor InvoSurg shows ads.

### Which is updated more often, i or InvoSurg?

i ships an update every 4 months, and InvoSurg every 10 months. Most recently, i was updated on September 21, 2026 and InvoSurg on October 12, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*