Brian Rainier T. Herradura | Beverly Anne P. Portugal | Olivia C. Flores
Introduction : Balanced general anesthesia technique is a popular choice for induction because it can minimize potential side effects from individual drugs when otherwise used alone. However, hypotension is still a common occurrence during induction. Perfusion Index (PI) has been used as a measure of systemic vascular resistance and has shown to predict hypotension after regional anesthesia and propofol induction. This study aimed to determine whether baseline PI can predict hypotension following balanced general anesthesia induction and determine a cut-off value where hypotension is expected to occur. Methods : Thirty-five ASA I/II adults for elective surgery under general anesthesia were enrolled. Heart rate, blood pressure and PI were measured every minute from baseline to 5 minutes following induction and 10 minutes after endotracheal intubation. Hypotension was defined as fall in systolic BP (SBP) by >30% of baseline and/or mean arterial pressure (MAP) to <60 mmHg. Severe hypotension (MAP of <55 mm Hg) was treated. Results : No hypotension was observed in the first 5 minutes. Within 10 minutes, hypotension occurred in 8.6% by SBP criterion and 2.6% by MAP criterion. Within 15 minutes, hypotension was seen in 5.7% by SBP and MAP criterion, respectively. PI showed very low (r < 0.2) to low (r = 0.2 to 0.39), negative to positive and insignificant correlation (p > 0.05) with hypotension whether using SBP or MAP criterion and whether observed at 10 or 15 minutes of anesthesia induction. The Area under the ROC curve is 0.397, 95% CI [0 .126, 0.667], p = 0.431. Conclusion : This study lends inconclusive evidence on the usefulness of Innovo Deluxe Fingertip Pulse Oximeter with Plethysmograph and Perfusion Index to predict intraoperative hypotension following balanced general anesthesia induction for this sample of patients. However, there was a positive, moderate (r=0.538, 0.501 and 0.469) and significant (p<0.5) correlation between perfusion index and SBP, Diastolic BP and MAP, respectively.
1. Mowafi HA, Ismail SA, Shafi MA, Al-Ghamdi AA. The efficacy of perfusion index as an indicator for intravascular injection of epinephrine-containing epidural test dose in propofol-anesthetized adults. Anesth Analg 2009 Feb; 108(2): 549-53.
2. Hager H, Reddy D, Kurz A. Perfusion index - a valuable tool to assess changes in peripheral perfusion caused by sevoflurane. Anesthesiology 2003; 99: A593.
3. Kowalczyk M, Fijalkowska A, Nestorowicz A. New- generation pulse oximetry for the assessment of peripheral perfusion during general anaesthesia - a comparison between propofol and desflurane. Anaesthesiol Intensive Ther 2013; 45(3): 138–44. . Krishnamohan A, Siriwardana V, Skowno JJ. Using a pulse oximeter to determine clinical depth of anesthesia - investigation of the utility of the perfusion index. Paediatr Anaesth 2016 Nov; 26(11): 1106-11.
5. Mizuno J, Morita Y, Kakinuma A, Sawamura S. General anaesthesia induction using general anaesthetic agents and opioid analgesics increases perfusion index (PI) and decreases pleth variability index (PVI): Observational clinical study. Sri Lankan J Anaesth 2012; 20(1): 7-12.
6. Kakazu CZ, Chen BJ, Kwan WF. Masimo set technology using perfusion index is a sensitive indicator for epidural onset. Anesthesiology 2005; 103: A576.
7. Uemura A, Yagihara M, Miyabe M. Pulse oximeter perfusion index as a predictor for the effect of pediatric epidural block. Anesthesiology 2006; 105: A1354.
8. Atef HM, Fattah SA, Abd Gaffer ME, Al Rahman AA. Perfusion index versus non-invasive hemodynamic parameters during insertion of I-gel, classic laryngeal mask airway and endotracheal tube. Indian J Anaesth 2013; 57: 156-62.
9. Klijn E, Groeneveld AB, van Genderen ME, Betjes M, Bakker J, van Bommel J. Peripheral perfusion index predicts hypotension during fluid withdrawal by continuous venovenous hemofiltration in critically ill patients. Blood Purif 2015; 40: 92-8.
10. Mehandale SG, Rajasekhar P. Perfusion index as a predictor of hypotension following propofol induction – a prospective observational study. Indian J Anaesth 2017; 61: 990-5.
11. van Genderen ME, Bartels SA, Lima A, Bezemer R, Ince C, Bakker J, van Bommel J. Peripheral perfusion index as an early predictor for central hypovolemia in awake healthy volunteers. Anesth Analg 2013 Feb; 116(2): 351-6.
12. Lu W, Dong J, Xu Z, Shen H, Zheng J. The pleth variability index as an indicator of the central extracellular fluid volume in mechanically-ventilated patients after anesthesia induction: Comparison with initial distribution volume of glucose. Med Sci Monit 2014; 20: 386-92.