ABSTRACT
Objective:To evaluate the changes in the systemic circulation and microcirculation in the patients undergoing gastrointestinal surgery under general anesthesia in Xining area.Methods:A total of 27 patients, aged 18-60 yr, underwent gastrointestinal surgery under general anesthesia in Xining area (2 260 m), of long lived (more than two generations) Han nationality, with no alternating life between plateau and plain, with no cardiopulmonary abnormalities, were enrolled.Anesthesia was induced with midazolam, sufentanil, etomidate, and cisatracurium and maintained with propofol, remifentanil and cisatracurium.At 5 min before induction of anesthesia (T 1), 10 min after induction of anesthesia (T 2), 1 h after start of operation (T 3), immediately after the end of operation (T 4), and 30 min after recovery from anesthesia (T 5), systemic circulation indexes including cardiac output (CO), stroke volume (SV), stroke volume variability (SVV), systemic vascular resistance index (SVRI), and mean arterial pressure (MAP) and heart rate (HR) were recorded, and sublingual microcirculation indexes including total vascular density (TVD), perfused vessel density (PVD), portion of perfused vessels (PPV), and microvascular flow index (MFI) were determined by sidestream dark field imaging. Results:Systemic circulation Compared with the baseline at T 1, CO and HR were significantly decreased at T 2-4, SVV was decreased at T 5, SVRI was increased at T 3 and T 4, and MAP was decreased at T 2 ( P<0.05). Compared with those at T 2, CO and SV were significantly increased at T 5, SVV was decreased at T 5, SVRI was increased at T 3 and T 4, and MAP was increased at T 4 and T 5 ( P<0.05). Compared with those at T 3, SV was significantly decreased at T 4, CO was increased at T 5, and SVV and SVRI were decreased at T 5 ( P<0.05); Compared with those at T 4, CO, SV and HR were significantly increased at T 5, and SVV and SVRI were decreased at T 5 ( P<0.05). Microcirculation Compared with those at T 1, TVD, PVD, PPV and MFI were significantly decreased at T 2-4, and PPV and MFI were decreased at T 5 ( P<0.05). Compared with those at T 2, TVD was significantly increased at T 5, PVD was increased at T 4 and T 5, and PPV was increased at T 3 and T 4 ( P<0.05). TVD was significantly higher at T 5 than at T 3( P<0.05). TVD was significantly higher at T 5 than at T 4 ( P<0.05). Conclusions:The density of microcirculation and blood flow rate are decreased after induction of general anesthesia and during anesthesia operation, which are most significant at the initial stage after induction, and decoupling between systemic circulation and microcirculation occurs during operation and anesthesia resuscitation in the patients at high altitude.
ABSTRACT
Objective To observe the changes in microcirculation after induction of anesthesia in patients in plateau region. Methods Ten patients of both sexes, aged 35-58 yr, weighing 52-87 kg, of American Society of Anesthesiologists physical statusⅠ or Ⅱ, were enrolled in this study. Anesthesia was induced with intravenous etomidate 0. 3 mg∕kg, sufentanil 0. 75 μg∕kg and vecuronium 0. 10 mg∕kg. Me-chanical ventilation was performed after tracheal intubation. Fluid was replaced by intravenously infusing lactated Ringer′s solution 500 ml over 30-45 min after completion of anesthesia induction. At 5 min before anesthesia induction, 5 min after induction and after the end of fluid replacement, the hemodynamic pa-rameters such as heart rate (HR), SpO2and mean arterial pressure (MAP) were recorded, and microcir-culatory indices such as total vascular density (TVD), perfused vessel density (PVD), proportion of per-fused small vessels (PPV) and microvascular flow index (MFI) were measured. Results Compared with the baseline value before anesthesia induction, HR was significantly increased, SpO2and MAP were de-creased, TVD, PVD, PPV and MFI were decreased at 5 min after anesthesia induction (P＜0. 05). Com-pared with the baseline value at 5 min after anesthesia induction, HR was significantly decreased, and SpO2and MAP were increased immediately after fluid replacement (P＜0. 05), and no significant change was found in TVD, PVD, PPV or MFI immediately after fluid replacement (P＞0. 05). Conclusion Mi- crocirculatory disturbance is obvious after induction of general anesthesia in patients undergoing operation in plateau region, and no marked improvement is found in microcirculation after rapid fluid replacement, which may be the main cause of metabolic disorders such as acidosis after operation.