Intraoperative SpO2 Research Articles

Intraoperative FiO2 and risk of impaired postoperative oxygenation in lung resection: A propensity score-weighted analysis.

To assess whether, in a lung resection cohort with a low probability of confounding by indication, higher FiO2 is associated with an increased risk of impaired postoperative oxygenation - a clinical manifestation of lung injury/dysfunction. Pre-specified registry-based retrospective cohort study. Two large academic hospitals in the United States. 2936 lung resection patients with an overall good intraoperative oxygenation (median intraoperative SpO2≥95%). We compared patients with a higher (≥0.8) and lower (<0.8) median intraoperative FiO2 after propensity score-weighting for 75 perioperative variables based on a causal inference framework. The primary outcome of impaired oxygenation was defined as at least one of the following within seven postoperative days: (1) SpO2<92%; (2) imputed PaO2/FiO2<300mmHg [(1) or (2) at least twice within 24h]; (3) intensive oxygen therapy (mechanical ventilation or>50% oxygen or high-flow oxygen). Among the 2936 included patients, 2171 (73.8%) received median intraoperative FiO2≥0.8. Impaired postoperative oxygenation occurred in 1627 (74.9%) and 422 (55.2%) patients in the higher and lower FiO2 groups, respectively. In a propensity score-weighted analysis, higher intraoperative FiO2 was associated with an 84% increase in the likelihood of impaired postoperative oxygenation (OR 1.84; 95% CI 1.60 to 2.12; P<0.001). Despite plausible harm from hyperoxia, high intraoperative FiO2 is extremely common during lung resection. Nearly three-quarters of lung resection patients with acceptable oxygenation received median intraoperative FiO2≥0.8. Such higher FiO2 was associated with an increased risk of impaired postoperative oxygenation - a clinically relevant manifestation of lung injury or dysfunction. This observation supports the administration of a lower (< 0.8) intraoperative FiO2 and its further assessment in clinical trials.

Nomogram for intraoperatively acquired pressure injuries in children undergoing cardiac surgery with cardiopulmonary bypass: a retrospective study

BackgroundWe aimed to develop and validate a nomogram for predicting the risk of intraoperatively acquired pressure injuries (IAPIs) in children undergoing cardiac surgery with cardiopulmonary bypass (CPB).MethodsThis study retrospectively included 208 children aged 21 days to 8 years who underwent cardiac surgery with CPB in a tertiary hospital in China between January 2020 and October 2023. All patients’ data were collected from the hospital’s medical record system and randomly divided into the training (n = 146) and validation (n = 62) cohorts by a ratio of 7:3. Logistic regression analysis was conducted in the training cohort to identify independent risk factors and establish the nomogram. Finally, calibration curves, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA) were performed in both cohorts to validate the predictive ability of the nomogram.Results43 (14.7%) children developed IAPIs. Multivariate analysis showed that low Braden Q scores, use of steroids, skin abnormalities, and low intraoperative SpO2 were independent risk factors for IAPIs. A nomogram integrating the 4 factors was established. The areas under the curve (AUCs) of the nomogram were 0.836 and 0.903 in the training and validation cohorts, respectively. Furthermore, calibration curves and DCA demonstrated good calibration and clinical applicability of the nomogram.ConclusionWe constructed a reliable nomogram based on specific risk factors for children undergoing cardiac surgery with CPB, which could be used as an effective and convenient tool for prevention of IAPIs.

Relationship of Intraoperative SpO2 and ETCO2 Values with Postoperative Hypoxemia in Elderly Patients after Non-Cardiac Surgery.

Elderly patients are at higher risk of postoperative hypoxemia due to their decreased respiratory function. The aim of this study was to investigate the relationship of intraoperative oxygen saturation (SpO2) and end-expiratory carbon dioxide (ETCO2) values with postoperative hypoxemia in elderly patients. The inclusion criteria were: 1) patients aged≥75 years; 2) underwent general anesthesia in non-cardiac surgery; 3) operative time longer than two hours; and 4) admission to the intensive care unit (ICU) following surgery performed between January and December 2019. Intraoperative SpO2 and ETCO2 values were collected every minute for the first two hours during surgery. The 253 patients were divided into two groups: SpO2≥92% and SpO2<92%. The time-weighted averages of intraoperative SpO2 and ETCO2 were used to compare differences between the two groups. The incidence of postoperative hypoxemia was 22.5%. For similar ventilator settings, patients with postoperative hypoxemia had lower intraoperative SpO2 and higher ETCO2 values. Sex, ASA classification, and intraoperative SpO2 were independent risk factors for postoperative hypoxemia. In conclusion, postoperative SpO2<92% was a frequent occurrence (> 20%) in elderly patients who underwent major non-cardiac surgery. Postoperative hypoxemia was associated with low intraoperative SpO2 and relatively higher ETCO2.

Safety and Utility of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) for Laser Laryngeal Surgery.

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) is gaining acceptance as a safe method for apneic ventilation and oxygenation during laryngeal procedures, but remains controversial during laser laryngeal surgery (LLS) due to the theoretical risk of airway fire. This study describes our experience with THRIVE during LLS. Retrospective cohort study. Stanford University Hospital, October 15, 2015 to June 1, 2021. Retrospective chart review of patients ≥18 years who underwent LLS involving the CO2 or KTP laser with THRIVE as the primary mode of oxygenation. A total of172 cases were identified. 20.9% were obese (BMI ≥ 30). Most common operative indication was subglottic stenosis. The CO2 laser was used in 79.1% of cases. Median lowest intraoperative SpO2 was 96%. 44.7% cases were solely under THRIVE while 16.3% required a single intubation and 19.2% required multiple intubations. Mean apnea time for THRIVE only cases was 32.1 minutes and in cases requiring at least one intubation 24.0 minutes (p < .001). Mean apnea time was significantly lower for patients who were obese (p < .001) or had a diagnosis of hypertension (p = .016). Obese patients and patients with hypertension were 2.03 and 1.43 times more likely to require intraoperative intubation, respectively. There were no intraoperative complications or fires since the institution of our LLS safety protocol. By eliminating the fuel component of the fire triangle, THRIVE can be safely used for continuous delivery of high FiO2 during LLS, provided adherence to institutional THRIVE-LLS protocols.

Retroperitoneoscopic Surgery in Children Does Not Cause Pathological Desaturation in Cerebral/Renal Oxygenation on Near-Infrared Spectroscopy Compared with Laparoscopic and Thoracoscopic Surgery.

Introduction: Cerebral and renal regional oxygen saturation (C-rSO2 and R-rSO2, respectively) were monitored using near-infrared spectroscopy in pediatric patients (range: 0.3-14.3 years) during minimally invasive surgery (MIS) taking at least 3 hours performed by laparoscopy (Lap), thoracoscopy (Tho), or retroperitoneoscopy (Ret) from January 2019 to December 2021. Materials and Methods: Criteria compared were operative time, preoperative/intraoperative hemoglobin, blood loss, mean arterial pressure, arterial partial pressure of carbon dioxide (PaCO2), peripheral oxygen saturation (SpO2), C-rSO2, and R-rSO2. Pathological desaturation (PD) was defined as >20% decrease from baseline, and statistical significance as P < .05. Results: Subjects (n = 79) were similar for gender, age, and body mass index. MIS procedures were: Lap = 45, Tho = 20, Ret = 14; one Lap case required conversion for severe adhesions, not PD. Intraoperative PaCO2 (mmHg) was significantly higher in Tho (maximum: 59.5 ± 17.0, minimum: 39.9 ± 7.5) versus Lap (maximum: 39.9 ± 5.1, minimum: 34.6 ± 3.9) and Ret (maximum: 37.8 ± 4.2, minimum: 35.0 ± 3.3); P < .0001 (maximum), P = .0013 (minimum). Minimum intraoperative SpO2 was significantly lower in Tho (P < .0001). Mean operative times were significantly shorter in Tho (259 ± 114 minutes) versus Lap (433 ± 154 minutes) and Ret (342 ± 100 minutes); P < .0001, respectively. PD was absent during Ret (C-rSO2: 0/14 = 0% and R-rSO2: 0/14 = 0%). Differences in PD for Lap (C-rSO2: 7/45 = 15.6% and R-rSO2: 10/45 = 22.2%) and Tho (C-rSO2: 9/20 = 45.0%, and R-rSO2: 7/20 = 35.0%) were significant; P = .0028 for C-rSO2 and P = .0497 for R-rSO2. Hemoglobin and blood loss were similar. Conclusions: PD was absent during Ret, despite longer operative times. If Ret is indicated for a procedure, neurodevelopmental sequelae of MIS could be minimized.

The effect of minimal-flow and high-flow hypotensive anesthesia on oxidative stress

Objective: The main objective of this study was to compare the effects of minimal and high gas flow-controlled hypotension applications on IMA and thiol/disulfide balance, which are indicators of oxidative stress.Methods: Patients undergoing elective tympanoplasty were randomized to two groups as minimal-flow and high-flow anesthesia groups. Minimal flow anesthesia was performed with 5L/min fresh gas flow reduced to 0.4 L/min. High flow was administered as 2 L/min fresh gas. Preoperative and intraoperative SpO2, StO2, EtCO2, mean arterial pressure and heart rate values were recorded. Preoperative and intraoperative IMA, total thiol, native thiol, disulfide, disulfide/native thiol and disulfide/total thiol values were recorded and compared between the two groups. Results: The mean intraoperative arterial pressure was statistically notably higher in the high flow group (p=0.048). The mean intraoperative SPO2 value was remarkably higher in the minimal flow group (p=0.032). The mean EtCO2 value was notably lower in the minimal flow group at 5 minutes and 15 minutes of the operation (p=0.029; p=0.048). The mean preoperative and intraoperative IMA values were statistically notably higher in the minimal flow group compared to the high flow group (for both, p=0.001). There was no remarkable difference between the groups in terms of the other monitored parameters (for all, p&amp;gt;0.05).Conclusion: IMA value was found to be significantly higher with minimal-flow anesthesia. However, no notable difference was found in terms of thiol/disulfide homeostasis, indicating the need for further comprehensive studies in order to draw a definitive conclusion

Perioperative airway management of infantile subglottic hemangioma

Objective:To investigate the relevant influencing factors for perioperative airway events of infantile subglottic hemangioma, and to further discuss the strategies of perioperative airway management. Methods:A total of 36 infants with subglottic hemangioma that had no response to the drug therapy and underwent surgical treatment from July 2007 to April 2017 were enrolled. The relevant influencing factors, including gender, age, birth weight, age of onset, degree of tracheal stenosis and histories of underlying diseases（congenital heart disease and respiratory disease）, were also recorded simultaneously. Intraoperative SpO₂ decline, intraoperative emergency tracheal intubation, intraoperative emergency tracheotomy, whether preserving tracheal intubation after operation or not, and postoperative emergency tracheal intubation were included in the perioperative airway events of infantile subglottic hemangioma. The relevant influencing factors of perioperative airway events were analyzed so that meaningful statistical indicators were selected for grouped logistic regression analysis, and the correlation was evaluated based on OR value and 95% confidence interval（CI）. Based on the correlation between influencing factors and airway events, perioperative airway management was discussed. Results:①The degree of tracheal stenosis was a risk factor for SpO₂ decline（95%CI[2.121-33.818]）; ②The degree of airway stenosis, history of comorbid cardiovascular disease and respiratory disease were the influencing factors for intraoperative emergency tracheal intubation（95%CI[0.863-21.692], [0-+∞] and [1.741-232.403], respectively）; ③The degree of airway stenosis was the influencing factor for postoperative emergency tracheal intubation（95%CI[1.277-20.421]）; ④The degree of airway stenosis was a risk factor for whether preserving postoperative tracheal intubation or not（95%CI[1.523-13.296]）. Conclusion:①Infants with a history of preoperative underlying diseases are more likely to present with intraoperative airway instability and SpO₂ decline, which deserves more preoperative and postoperative attention. Tracheal intubation should be performed timely in case of intraoperative SpO₂ decline. ②Preoperative tracheotomy should be performed in infants with preoperative grade Ⅲ airway stenosis, especially those with comorbid heart diseases or respiratory diseases. ③The degree of airway stenosis is an extremely important influencing factor for perioperative airway management of infantile subglottic hemangioma. For infants whose airway stenosis were greater than 60% of airway diameter, the airway maintenance should be closely monitored. Once SpO₂ decreases, tracheal intubation should be performed immediately. It's recommended to preserve tracheal intubation so as to ensure the airway stability. The tracheal intubation could be prolonged to 48-72 hours postoperatively. ④The surgical approach has no significant effect on perioperative airway management.

The Incidence of Tracheal Bronchus in Thoracic Surgery Patients and Its Implication for Lung Isolation: A Retrospective Cohort Study

To investigate the incidence of tracheal bronchus (TB) and explore its implication for lung isolation. Retrospective cohort study. Academic, tertiary care hospital. The study comprised 7,102 thoracic patients with- one lung ventilation. No intervention. Two independent anesthesiologists reviewed the computed tomography images to identify the presence of a TB, and their results were confirmed by a radiologist. The clinical data of patients with a TB were obtained from the electronic medical record. Data regarding the device used to provide lung isolation, preoperative oxygen saturation (SpO2), and intraoperative SpO2 during one- lung ventilation were obtained from the electronic anesthesia record. The incidence of TB was 1.08% (77 of 7,102). The TB arose from the right side of the trachea in all 77 patients, including 70 type Ⅲ TBs and 7 type Ⅱ TBs. Left- and right-sided double-lumen tubes (DLTs) were used in 54 and 23 patients, respectively. For patients with a left-sided DLT, the median SpO2 and incidence of hypoxemia (SpO2 <90%) were 97% and 6 of 54 (11.1%), respectively. For patients with a right DLT, the median SpO2 and incidence of hypoxemia were 95% and 7 of 20 (35.0%), respectively. There were significant differences in the mean SpO2 and the incidence of hypoxemia between patients intubated with left- and right-sided DLTs (p = 0.014 and p = 0.016, respectively). Preoperative diagnosis of TB is important when lung isolation is needed. The left-sided DLT can be used for most patients with a TB.

Improving preoperative identification of infants at risk for severe retinopathy of prematurity.

To increase preoperative identification of at-risk infants for severe Retinopathy of prematurity (ROP) to >95% by August 2016, with a secondary aim of reducing the number of infants with 100% intraoperative peripheral oxygen saturation (SpO2) during the same time. Prospective quality improvement project centered on preterm surgical infants admitted to Primary Children's Hospital (n = 41). Preoperative ROP risk identification rates were analyzed using an annotated run chart, intraoperative SpO2 and laser intervention were compared using un-paired t test. Preoperative identification of ROP risk increased from 60 to 100% and no infant was exposed to 100% SpO2 intraoperatively during the study period. The incidence of laser intervention in this population decreased by 45% from 22 to 12% (p = 0.21). Simplifying our preoperative handoff increased our rates of correct identification and communication ROP risk in preterm infants while decreasing exposure to 100% SpO2.

A Propensity Score-Matched Analysis for Non-Intubated Thoracic Surgery.

BackgroundMost observations of non-intubated anesthesia under spontaneous breathing are small-cohort, non-homogeneous surgery types and lack an intubation control. We therefore retrospectively compared the perioperative conditions and postoperative recovery of non-intubated video-assisted thoracoscopic surgery (NIVATS group) and intubated VATS (IVATS group) with a propensity score-matching analysis.Material/MethodsWe case-matched 119 patients in the NIVATS group with patients in the IVATS group by a propensity score-matched analysis. All of them underwent lobectomy.ResultsIn the NIVATS group, operative and anesthesia times were significantly shorter (P<0.01). NIVATS showed a faster and more stable recovery in the PACU, postoperative awaking and post-anesthesia care unit (PACU) stay times was shorter (P<0.01), and use of sedatives and analgesics was lower (P<0.05). The incidence of pulmonary exudation, atelectasis, and pleural effusion were higher (P<0.05). Although intraoperative SpO2 was lower and PETCO2 was higher in the NIVATS group (P<0.01), postoperative PaCO2 and SaO2 in both groups were similar (P>0.05). Postoperative counts of leukocytes and neutrophils and hemoglobin levels also had no difference between the 2 groups (P>0.05).ConclusionsNIVATS has a more rapid and stable recovery in the PACU, and has no significant influence on oxygenation, but is more likely to cause postoperative radiologic complications.

Nonopioid versus Opioid Based General Anesthesia Technique for Laparoscopic Cholecystectomy

Background: The choices of premedication and anesthetic techniques are able to influence the neurohormonal stress response by modulating the pathophysiological pathways. Various pharmacological agents like nitroglycerine, beta blocker, and opioids were used to decrease surgical stress of laparoscopic procedures to improve outcome, with their own limitations. Objective: It was to compare the effect of opioid-free (using dexmedetomidine and propofol) and opioid-based (using fentanyl and propofol) TIVA techniques on hemodynamic stability, sedation postoperative pain intensity and the incidence of side effects in patients scheduled for LC. Patients and Methods: Eighty patients who were scheduled for elective laparoscopic cholecystectomy were included in this study. Before induction of anesthesia, patients were randomly divided into two equal groups: (40 each). Dexmedetomidine group(Non-opioid group) received dexmedetomidine (1 µg/kg) over 10 minutes before induction of anesthesia followed by continuous infusion of 0.5 µg/kg/hr. till the end of surgery and Fentanyl group (Opioid group) received fentanyl (1.0 µg/kg) over 10 minutes before induction of anesthesia followed by continuous infusion of 0.4 µg/kg/hr. till the end of surgery. Results: The results of the present study showed that there were no significant differences between the two groups regarding HR and MAP except after loading dose of the studied drugs, after intubation, after pneumoperitoneum, 15 min, 30 min, 45 min, and 60 min after induction where it was lower in dexmedetomidine group than fentanyl group. There were no significant differences between two groups regarding intraoperative SPO2, postoperative SPO2 and blood glucose level (mg/dl). Conclusion: This study concluded that dexmedetomidine is better than fentanyl for patients who undergo elective laparoscopic cholecystectomy due to perioperative maintaining of hemodynamic stability, decrease dosages of postoperative analgesics, prolong the duration of postoperative analgesia and decrease postoperative nausea and vomiting.

Effect of Dexmedetomidine Versus Nalbuphine as an Adjuvant on Paravertebral Block to Manage Postoperative Pain After Mastectomies.

Background and ObjectiveBreast cancer is the commonest cancer in women worldwide. Many patients are frequently admitted to the operating theaters for mastectomies. Thoracic paravertebral block (PVB) is increasingly used as an effective means for post-operative pain relief. The present study aimed at evaluating the effectiveness and safety of dexmedetomidine and nalbuphine as an adjuvant to bupivacaine local anesthetic in thoracic paravertebral block in breast cancer surgeries.MethodsA total of 60 female patients aged 18 to 78 were included in the study, and ASA I, II, III were scheduled for mastectomy. These patients were unsystematically assigned into three 20-member groups: group PB received bupivacaine (0.3 mL/ kg) + 1 mL (0.9% sodium chloride) normal saline; group PBD received bupivacaine (0.3 mL/kg) + dexmedetomidine 1 μg/kg; and Group PBN received bupivacaine (0.3 mL/kg) and 10 mg (1 mL) nalbuphine. Demographic data, intraoperative SPO2, ETCO2, HR, SBP and DBP, pain scores (at rest and movement), and sedation scores were recorded every 30 minutes during the initial 2 hours and 4, 8, 24, and 48 hours from T0. Also, postoperative tramadol consumption, the time to the first analgesic request, and any complications were also recorded.ResultsThere were no statistically significant differences among the three groups regarding demographic data, SPO2, ETCO2, HR, SBP and DBP intraoperatively. Moreover, no significant difference was found in HR, SBP and DBP postoperatively. Postoperative pain scores were significantly higher in group BP, whether at rest or movement. The sedation was significantly higher in PBD group in the first 12 hours postoperatively. There was a significantly lower postoperative tramadol consumption in PBN group and a significantly longer time to the first analgesic request than other groups. No complications were reported in any group.ConclusionsAddition of nalbuphine 10 mg as an adjuvant to bupivacaine local anesthetic in PVB improved the quality of the block and decreased postoperative analgesic requirements than the bupivacaine only group and dexmedetomidine and bupivacaine group. However, adding dexmedetomidine to bupivacaine increased the time to the first analgesic request and more sedation than bupivacaine and bupivacaine and nalbuphine.

Spontaneous ventilation anaesthesia: total intravenous anaesthesia with local anaesthesia or thoracic epidural anaesthesia for thoracoscopic bullectomy.

At present, few data exist regarding the comparisons of perioperative outcomes and recurrence of spontaneous ventilation (SV) video-assisted thoracic surgery (VATS) bullectomy using total intravenous anaesthesia (TIVA) with local anaesthesia (LA) or thoracic epidural anaesthesia (TEA). We evaluated the feasibility and safety of TIVA with LA in the management of primary spontaneous pneumothorax (PSP). We conducted a single-institution retrospective analysis of patients undergoing VATS bullectomy between July 2011 and May 2015; 240 patients were included for analysis. Preoperative, intraoperative and postoperative variables of patients undergoing VATS bullectomy using TIVA-TEA (n = 140) were compared with those using TIVA-LA (n = 100). Baseline demographics were similar between groups. No patients in either group required conversion to thoracotomy. Three patients (TIVA-TEA: 2; TIVA-LA: 1) required conversion to intubated general anaesthesia. Both groups had comparable surgical duration, estimated blood loss, peak EtCO2 and lowest intraoperative SpO2 level. Postoperatively, thoracic drainage volume, duration of chest tube drainage and hospitalization cost did not differ between groups. The incidence of postoperative complications between groups was not significant (2% for TIVA-TEA vs 2% for TIVA-LA, P = 1.00). Pneumothorax recurrence rate was 3% in TIVA-TEA cases (n = 4) and 2% in TIVA-LA cases (n = 2). SV-VATS bullectomy using TIVA with LA or TEA is technically feasible and safe. Both groups have comparable short-term outcomes and recurrence rates; TIVA-LA seems a valid alternative to TIVA-TEA for the surgical management of PSP under SV.

Monitorización de los efectos de la raquianestesia sobre la saturación de oxígeno cerebral en pacientes ancianos con el uso de espectroscopia de luz próxima al infrarrojo

ObjectiveCentral blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. MethodsTwenty-five ASA I–II Group patients aged 65–80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. ResultsSignificant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. ConclusionEvaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning.

Monitoramento dos efeitos da raquianestesia sobre a saturação de oxigênio cerebral em pacientes idosos com o uso de espectroscopia de luz próxima ao infravermelho

ObjectiveCentral blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. MethodsTwenty‐five ASA I–II Group patients aged 65–80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre‐ and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. ResultsSignificant changes in pre‐ and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. ConclusionEvaluation of the data obtained in the study demonstrated that post‐spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning.

Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy

ObjectiveCentral blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. MethodsTwenty-five ASA I–II Group patients aged 65–80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. ResultsSignificant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. ConclusionEvaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning.

Pulse Oximetry Desaturation Following The Use Of Isosulfan Blue: Influence Of The Site Of Injection

Purpose: To examine the influence of injection site on pulse oximetry oxyhemoglobin saturation (SpO2), following intraoperative injection of isosulfan blue (IB) into breast or cutaneous melanoma regions. Purpose: Anesthetic records of 497 patients with breast cancer and 824 with cutaneous melanoma were reviewed. SpO2 was recorded every 15 minutes from 15 minutes before until 120 minutes after IB injection. Results: The mean SpO2 was lower in the breast than melanoma group at 15-120 minutes after IB injection (p 4% SpO2 decrease) was higher in the breast (20.9%) than melanoma group (1.7%) (p<0.00001). The breast group had a greater maximum SpO2 decrease and lower minimum SpO2 during desaturation (p<0.00001), higher incidence of minimum SpO2<95% (p<0.00001), and earlier desaturation onset (p=0.0088). Risk factors for desaturation of any severity were breast group, higher body mass index, and lower intraoperative FiO2, and for major desaturation were breast group and higher baseline intraoperative SpO2. Conclusion: Injection of IB into breast tissue was associated with a higher incidence, greater severity, and earlier onset of SpO2 desaturation, compared to intradermal injection into the area surrounding cutaneous melanomas.

Intra-operative gas exchange and post-operative hypoxaemia

The relation between intra-operative gas exchange and post-operative oxygen saturation was examined using pulse oximetry (SpO2) 30 h after anaesthesia for upper abdominal surgery. The inspired oxygen partial pressure (PIO2) was varied during anaesthesia to produce a plot of PIO2 vs. SpO2. Gas exchange during anaesthesia was inferred from the relation between PIO2 and SpO2 which was described by its lateral and vertical displacement away from the position of a standard oxygen dissociation curve. With patients breathing air, the SpO2 was measured over a 10-min period at 30 h after surgery. The correlation coefficient of the lateral displacement with post-operative SpO2 was 0.7, and that of the vertical displacement with post-operative SpO2 was 0.66. The correlation coefficient of intra-operative SpO2 at PIO2 = 21 kPa with post-operative SpO2 was 0.69. It can be concluded that gas exchange abnormalities during anaesthesia deduced from the displacement of the PIO2 vs. SpO2 curve correlate with SpO2 30 h post-operatively and may help to identify patients at risk of post-operative hypoxaemia.