John Greenwood, MD
University of Pennsylvania - Perelman School of Medicine
Philadelphia, Pennsylvania
Disclosure information not submitted.
Fatima Talebi, BS
Clinical Research Coordinator
University of Pennsylvania
Philadelphia, Pennsylvania, United States
Disclosure information not submitted.
David Jang, MD, MSc
Assistant Professor
University of Pennsylvania, United States
Disclosure information not submitted.
Audrey Spelde, MD
Assistant Professor - Anesthesiology & Critical Care
Perelman School of Medicine at the University of Pennsylvania, United States
Disclosure information not submitted.
Jiri Horak, MD
Associate Professor of Anesthesiology & Critical Care
Perelman School of Medicine at the University of Pennsylvania, United States
Disclosure information not submitted.
.jpg "Jacob Gutsche, MD, FCCM photo")
Jacob Gutsche, MD, FCCM
Associate Professor of Anesthesiology and Critical Care
Hospital of The University of Pennsylvania
Philadelphia, Pennsylvania, United States
Disclosure information not submitted.
John Augoustides, MD
Professor of Anesthesiology and Critical Care
University of Pennsylvania, United States
Disclosure information not submitted.
Todd Kilbaugh, MD
Associate Professor of Anesthesia, Critical Care, & Pediatrics
Childrens Hospital of Philadelphia, United States
Disclosure information not submitted.
Nuala Meyer, MD, MS
Assistant Professor
University of Pennsylvania Perelman School of Medicine
Philadelphia, Pennsylvania
Disclosure information not submitted.
Jan Bakker, MD, PhD, FCCP,FCCM
Professor, Department of Medicine
NYC Health + Hospitals Bellevue, United States
Disclosure information not submitted.
Benjamin Abella, MD, MPhil
Professor - Department of Emergency Medicine
Perelman School of Medicine at the University of Pennsylvania, United States
Disclosure information not submitted.
Title: Topical Nitroglycerin to Evaluate Microcirculatory Capacity During Circulatory Shock.
Introduction: Circulatory shock after cardiac surgery is associated with significant microcirculatory impairment (1). A topical nitroglycerin (NTG) challenge can identify smooth muscle-dependent microcirculatory reserve in healthy subjects, but this approach has not been evaluated in critically ill patients (2). Identifying unrecruited microcirculation could provide a simple point-of-care method to help clinicians optimize resuscitation strategies.
Methods: Baseline sublingual microcirculation measurements were obtained in patients requiring vasopressor and inotropic support to maintain hemodynamic goals after cardiac surgery using incident dark field (IDF) microscopy (CytoCam, Braedius Medical, Netherlands). A NTG challenge was performed by administering 0.1 mL of a topical NTG solution (0.01 mcg/mL) to the sublingual mucosa. Measurements were obtained immediately and 30 min after NTG application (recovery). Total vessel density (TVD), proportion of perfused vessels (PPV), and capillary red blood cell velocity (RBCv) were analyzed manually with computer-assisted software (AVA v3.2, Microvision Medical, Netherlands) in concordance with the 2nd ESICM consensus standards (3). Heart rate, mean arterial pressure, cardiac index, and SvO2 were measured continuously by arterial line and PA-catheter. Vitals and vasoactive infusion doses were recorded in 3 min intervals for 30 min after the NTG challenge.
Results: We enrolled 11 subjects, median [IQR] age 69 y [55-74], 60% were male. Surgical procedures included CABG (n=8), CABG plus valve (n=2), and valvular surgery (n=1). Six of the 11 patients had an increase in TVD > 20%. Nine patients had a > 50% increase in RBCv. Compared to baseline, there was an increase in mean TVD 23.1 (±4.3) vs. 27.6 (±4.7) mm/mm2, p=0.1, PPV 89 (±5.9) vs. 96 (±3.2)%, p</em><0.001, and RBCv 418 (±147) vs. 782 (±251) µm/s, p<0.01 with the NTG challenge. Recovery measurements were similar to baseline. Heart rate, MAP, CI, and vasoactive infusion doses did not change during or shortly after the NTG challenge.
Conclusion: Unrecruited microcirculation can be safely assessed with a topical nitroglycerin challenge using sublingual IDF in patients with circulatory shock. Identifying patients with underrecruited microcirculation may be a target for future interventional trials.