Introduction: Delegation of controlled medical acts by physicians to paramedics is an important component of the prehospital care framework. Where directives indicate that physician input is needed before proceeding with certain interventions, online medical control (a “patch”) exists to facilitate communication between a paramedic and a Base Hospital Physician (BHP) to request an order to proceed with that intervention. The quality and clarity of audio transmission is paramount for effective and efficient communication. The aim of this study was to examine the impact of audio transmission quality on the results of paramedic patch calls. Methods: Prehospital paramedic calls that included a mandatory patch point (excluding requests exclusively for termination of resuscitation and those records which were unavailable) were identified through review of all patch records from January 1, 2014 to December 31, 2017 for Paramedic Services in our region. Written Ambulance Call Reports (ACRs) and audio recordings of paramedic patches were obtained and reviewed. Pre-specified patch audio quality metrics, markers of transmission quality and comprehension as well as the resulting orders from the BHP were extracted. Differences between groups was compared using chi-square analyses. Results: 214 records were identified and screened initially. 91 ACRs and audio records were included in the analysis. At least one explicit reference to poor or inadequate call audio quality was made in 55/91 (60.4%) of calls and on average, 1.4 times per call. Of the 91 audited call records, 48 of 91 (52.7%) patches experienced an interruption of the call. Each time a call was interrupted, re-initiation of the call was required, introducing a mean [IQR] delay of 81 [33-68] seconds to re-establish verbal communication. Order requests made by paramedics in calls with no interruptions were approved in 30 of 43 patches (70%) while those requests made in calls with one or more interruptions were approved in only 21 of 48 cases (44%) (Δ26.0%; 95%CI 5.6-43.5%, p = 0.01). Conclusion: This retrospective review suggests that audio quality and interruptions of patch calls may impact a physician's ability to approve orders for interventions in the prehospital setting. Focus on infrastructure and technology underlying this important mode of communication may be a fruitful avenue for future improvements in systems where this may be an issue.