Blood gas studies during labaroscopy under general anesthesia.

Carbon dioxide output in laparoscopic cholecystectomy

Test the hypothesis that the center of ventilation, a measure of ventro-dorsal atelectasis, is posterior during supraglottic ventilation indicating better dependent-lung ventilation. Secondarily, we tested the hypothesis that supraglottic ventilation improves oxygenation and carbon dioxide elimination. Supraglottic and subglottic jet ventilation are both used during laryngotracheal surgery. Supraglottic jet ventilation may better prevent atelectasis and provide superior ventilation. Randomized, cross-over trial. Operating rooms. Patients having elective micro-laryngotracheal surgery. Patients were sequentially ventilated for 5min with one randomly selected type of jet ventilation before being switched to the alternative method. Regional ventilation distribution was estimated using electrical impedance tomography, with arterial oxygenation and carbon dioxide partial pressures being simultaneously evaluated. Thirty patients completed the study. There were no statistically significant or clinically meaningful differences in the center of ventilation with supraglottic and subglottic ventilation. However, ventilation with the supraglottic approach was about 4% higher in the ventromedial lung region and about 4% lower in the dorsal lung. Surprisingly, arterial blood oxygenation was considerably worse with supraglottic (173 [156, 199] mmHg) than subglottic ventilation (293 [244, 340] mmHg). Arterial carbon dioxide partial pressure was near 40mmHg with each approach, although slightly lower with supraglottic jet ventilation. The center of ventilation distribution, a measure of atelectasis, was similar with supraglottic and subglottic jet ventilation. Subglottic jet ventilation improved the dorsal-dependent lung region and provided superior arterial oxygenation. Both techniques effectively eliminated carbon dioxide, with the supraglottic approach demonstrating slightly superior efficacy.

Blood gas analysis, hematology, biochemistry and Apgar score during the first 24 hours of life of Mangalarga Marchador foals.

Arterial carbon dioxide partial pressure measurements using the NBP-75 microstream capnometer were compared with direct PaCO2 values in patients who were (a) not intubated and spontaneously breathing, and (b) patients receiving intermittent positive pressure ventilation of the lungs and endotracheal anaesthesia. Twenty ASA physical status I-III patients, undergoing general anaesthesia for orthopaedic or vascular surgery were included in a prospective crossover study. After a 20-min equilibration period following the induction of general anaesthesia, arterial blood was drawn from an indwelling radial catheter, while the end-tidal carbon dioxide partial pressure was measured at the angle between the tracheal tube and the ventilation circuit using a microstream capnometer (NBP-75, Nellcor Puritan Bennett, Plesanton, CA, USA) with an aspiration flow rate of 30 mL min(-1). Patients were extubated at the end of surgery and transferred to the postanaesthesia care unit, where end-tidal carbon dioxide was sampled through a nasal cannula (Nasal FilterLine, Nellcor, Plesanton, CA, USA) and measured using the same microstream capnometer. In each patient six measurements were performed, three during mechanical ventilation and three during spontaneous breathing. A good correlation between arterial and end-tidal carbon dioxide partial pressure was observed both during mechanical ventilation (r = 0.59; P = 0.0005) and spontaneous breathing (r = 0.41; P = 0.001); while no differences in the arterial to end-tidal carbon dioxide tension difference were observed when patients were intubated and mechanically ventilated (7. 3 +/- 4 mmHg; CI95: 6.3-8.4) compared to values measured during spontaneous breathing in the postanesthesia care unit, after patients had been awakened and extubated (6.5 +/- 4.8 mmHg; CI95: 5. 2-7.8) (P = 0.311). The mean difference between the arterial to end-tidal carbon dioxide tension gradient measured in intubated and non-intubated spontaneously breathing patients was 1 +/- 6 mmHg (CI95: -11-+13). We conclude that measuring the end-tidal carbon dioxide partial pressure through a nasal cannula using the NBP-75 microstream capnometer provides an estimation of arterial carbon dioxide partial pressure similar to that provided when the same patients are intubated and mechanically ventilated.

SummaryBlood was withdrawn from 15 dogs over the course of about 1 hour until the mean arterial blood pressure was reduced to 60 mm Hg. Small aliquots of additional blood were withdrawn in order to maintain the mean arterial blood pressure near 60 mm Hg for an additional hour. Oxymorphone (0.4 mg/kg) was then administered intravenously to ten dogs, and all measurements were repeated in 5, 15, 30, and 60 minutes. Five dogs served as controls.Heart rate, tidal volume, arterial oxygen, oxygen extraction, and pH significantly decreased after oxymorphone administration, while systemic and pulmonary arterial blood pressures, systemic vascular resistance (transiently), breathing rate, minute ventilation, physiologic dead space, venous admixture, venous oxygen, arterial and venous carbon dioxide, and bicarbonate concentration increased significantly. Cardiac output was also increased, but the change was not statistically significant. Oxymorphone was associated with significantly lower heart rate, tidal volume, arterial oxygen, and pH, and higher systemic and pulmonary arterial pressure, cardiac output, venous oxygen, and arterial and venous carbon dioxide, compared to the control group, which did not receive oxymorphone.Oxymorphone significantly improved cardiovascular performance and tissue perfusion in these hypovolemic dogs. Oxymorphone did cause a significant increase in arterial carbon dioxide and a decrease in arterial oxygenation. Oxymorphone is an opioid agonist that may represent a reasonable alternative for the induction of anesthesia in patients who are candidates for induction hypotension.

Clinical measures of ventilation and the relationship between arterial and end-tidal carbon dioxide tensions were studied during inhalational anaesthesia in 18 patients using a laryngeal mask airway or a facemask. Tidal volumes were similar in both groups but expired minute volume, respiratory rate and physiological deadspace ventilation were significantly increased in the facemask group. Both end-tidal and arterial carbon dioxide tensions were higher in the laryngeal mask group. Mean arterial to end-tidal carbon dioxide tension differences ranged from 0.13 to 4.13 kPa in the facemask group and from 0-1.73 kPa with the laryngeal mask airway. Pooled data analysis revealed a better correlation between arterial and end-tidal carbon dioxide tensions during laryngeal mask ventilation as compared to facemask breathing. With both techniques the arterial to end-tidal carbon dioxide tension difference was related to respiratory rate and physiological deadspace ventilation. Estimation of arterial carbon dioxide partial pressure by monitoring end-tidal carbon dioxide tension is more reliable with the laryngeal mask airway than during facemask breathing, in particular at small tidal volumes.

An investigation was carried out on 13 ASA class 1 or 2 adult patients undergoing laparoscopic cholecystectomy. Throughout laparoscopy, the end-tidal PCO2 was continuously monitored by capnography and the arterial hemoglobin oxygen saturation by pulse oximetry. Also, repeated measurements of arterial blood gases were done. Ventilation was controlled using an inspired oxygen concentration of 33% and tidal volume of 10 to 15 ml/kg at a rate of 10-14/min. The report showed that both the mean end-tidal PCO2 and arterial PCO2 progressively increased following carbon dioxide insufflation, to reach a maximal value after 30 min, with no significant change in the arterial-alveolar PCO2 gradient. Also, the arterial PO2 significantly decreased, and the hemoglobin oxygen saturation was always above 98% whether monitored by arterial blood gas analysis or by pulse oximetry. The results suggest that end-tidal capnography and pulse oximetry can be used as noninvasive techniques for monitoring arterial oxygenation and carbon dioxide elimination during laparoscopic cholecystectomy.

High‐flow nasal therapy – modelling the mechanism

Objective To compare the influence of tracheotomy after two wet fluid on airway and provide the basis for clinical treatment and care. Methods A total of 30 patients with severe brain injury stay neurosurgery tracheotomy were divided into 0.45% sodium chloride group and ambroxol hydrochloride group with 15 cases each by random digits table method, two airway humidification liquid (0.45% sodium chloride, 0.9% sodium chloride + ambroxol hydrochloride)were each instilled in the trachea inner sleeve. Blood gas analysis was performed and the levels of serum lung surface active substances related protein-A (SP-A protein), interleukin-6, interleukin-8, tumor necrosis factor-alpha(TNF-α) were measured by enzyme linked immunosorbent assay (ELISA)before 1 d and after 3,7,14 d of tracheotomy. Results There were significant differences in arterial blood oxygen partial pressure, arterial carbon dioxide partial pressure, oxygenation index after 14 d of tracheotomy between ambroxol hydrochloride group and 0.45% sodium chloride group:(110.72±26.75) mmHg(1 mmHg=0.133 kPa) vs.(89.39±21.98) mmHg, (30.44±6.75) mmHg vs. (35.12±7.28) mmHg, 333.23±80.56 vs. 270.93±77.21,t=29.49,-8.63,7.44,P<0.01.There were significant differences in the levels of serum SP-A protein, interleukin -6, interleukin -8, TNF-α after 14 d of tracheotomy between ambroxol hydrochloride group and 0.45% sodium chloride group:(191.34±1.21) ng/L vs. (61.92±12.0) ng/L, (2.62±0.23) ng/L vs.(5.42±0.16) ng/L,(124.56±2.10) ng/L vs. (185.91±1.48) ng/L, (31.32±1.38) ng/L vs.(69.13±1.16) ng/L,t=75.72, -13.51, -23.89, -20.97,P<0.01. Conclusions The airway humidification effect of ambroxol hydrochloride group is better than 0.45% sodium chloride group, it can improve the wetting effect, and better protect the lung tissue, reduce the incidence of lung infection, make it an ideal airway humidification liquid. Key words: Craniocerebral trauma; Tracheotomy; Ambroxol; Pulmonary surfactant-associated protein A; Airway humidification

Objective To evaluate the efficacy of self-made breathing circuit joint for intermittent positive pressure ventilation (IPPV) in patients with central airway obstruction undergoing interventional fiberoptic bronchoscopy (FOB). Methods Sixty-two patients of both sexes with central airway obstruction requiring tracheal intubation, aged 60-80 yr, with body mass index of 20-26 kg/m2, of American Society of Anesthesiologists physical status Ⅲ or Ⅳ and Medical Research Council dyspnea scale grade Ⅲ or Ⅳ, undergoing interventional FOB under general anesthesia, were divided into 2 groups (n=31 each) using a random number table: high frequency jet ventilation (HFJV) group and IPPV group.The patients were tracheally intubated after induction of general anesthesia.The self-made breathing circuit joint was connected, then the anesthesia machine was connected to perform IPPV, and the ventilator settings were adjusted to maintain the end-tidal pressure of carbon dioxide 35-45 mmHg in group IPPV, and HFJV was used in group HFJV.Before induction (baseline), at 10, 20, 30 and 40 min after start of operation, and at the end of operation, arterial blood samples were collected for blood gas analysis, the pH value, arterial oxygen partial pressure, and arterial carbon dioxide partial pressure were recorded.The development of hypercapnia was recorded. Results Hyoxemia was not found in the two groups.The incidence of hypercapnia was 74%, and in addition the incidence of severe hypercapnia was 10% in group HFJV.The incidence of hypercapnia was 16%, and all the patients presented with permissive hypercapnia in group IPPV.Compared with group HFJV, the incidence of hypercapnia was significantly decreased, and the pH value and arterial oxygen partial pressure were increased, and arterial carbon dioxide partial pressure was decreased from 10 min after start of operation to the end of operation in group IPPV (P<0.05). Conclusion The self-made breathing circuit joint provides better efficacy than HFJV when used for IPPV in the patients with central airway obstruction undergoing interventional FOB. Key words: Intermittent positive-pressure ventilation; Bronchoscopy; Airway obstruction

Cardiorespiratory changes induced by pneumoperitoneum and head-up tilt may generate alveolar ventilation to perfusion ratio changes and increased systemic vascular resistances. The reliability of end-tidal carbon dioxide tension and pulse oximetry in predicting arterial carbon dioxide partial pressure and arterial oxygen saturation may therefore be affected. The 35 ASA 1-2 patients in this study comprised 12 men and 23 women aged 48 (SD 17) years and weighing 71 (SD 14) kg. Twenty-nine were to undergo upper abdominal laparoscopy for cholecystectomy and six hyperselective vagotomy. Intra-abdominal pressure was 1.7 (SD 0.9) kPa and head-up tilt was 5.6 (SD 4.2) degrees. After abdominal insuflation, arterial carbon dioxide partial pressure significantly increased (p < 0.05). However, the arterial carbon dioxide partial pressure-end-tidal carbon dioxide partial pressure gradient remained constant throughout surgery. This gradient was highly correlated with arterial carbon dioxide partial pressure (p < 0.0001), but was not correlated with elapsed time, intra-abdominal pressure or head-up tilt. Arterial oxygen saturation was always greater than 95% in all patients and the arterial oxygen saturation-pulse oximetric saturation gradient was always less than or equal to +4%. In conclusion, end-tidal carbon dioxide partial pressure and pulse oximetric saturation allow reliable monitoring of arterial carbon dioxide partial pressure and arterial oxygen saturation in the absence of pre-existing cardiopulmonary disease and/or acute peroperative disturbance.

Objective To evaluate the effect of modified Huangqi decoction combined with routine western medicine on acute exacerbation chronic obstructive pulmonary disease (AECOPD). Methods A total of 84 patients with AECOPD who met the inclusion criteria were randomly divided into 2 groups, 42 in each group. The control group was treated with conventional Western medicine, while the observation group was treated with Huangqi decoction on the basis of the control group. The TCM symptoms and signs of the two groups were scored from cough, sputum expectoration, shortness of breath, wheezing and moist rale. The forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and the percentage of FEV1 in FVC (FEV1%) of the two groups were measured by automatic lung function analyzer. The blood oxygen partial pressure (PaO2), arterial blood carbon dioxide partial pressure (PaCO2) and arterial partial pressure oxygen (SaO2) were measured by gas analyzer. The serum CRP was detected by ELISA, and the serum procalcitonin (PCT) was detected by immunoluminescence. Results The total effective rate was 90.5% (38/42) in the observation group, which was 73.8% (31/42) in the control group, with significant difference between the two groups (Z=-3.225, P=0.004). After treatment, the scores of cough, sputum expectoration, shortness of breath, wheezing and moist rale in the observation group were significantly lower than those in the control group (t values were 3.225, 3.587, 3.552, 3.421, 3.785, all Ps<0.05), and the levels of FEV1, FVC and FEV1% in the observation group were significantly higher than those in the control group (t values were 3.586, 3.021, 5.026, all Ps<0.05). After treatment, the PaO2 and SaO2 levels in the observation group were significantly higher than those in the control group (t values were 4.022 and 4.251 respectively, all Ps<0.05), and PaCO2 levels in the observation group were significantly lower than those in the control group (t=4.572, P=0.018). The CRP and PCT in the observation group were significantly lower than those in the control group (t=4.635, 3.028, P<0.05). Conclusions The modified Huangqi decoction can improve the pulmonary function and clinical symptoms of AECOPD patients, reduce the levels of CRP and PCT, and improve the clinical efficacy. Key words: Pulmonary disease, chronic obstructive; Acute lung injury; Calcitonin; C-reactive albumin; Blood gas analysis; Huangqi decoction

Objective To explore the clinical value of the lung protective ventilation strategy in thoracoscopic and laparoscopic radical resection of esophageal cancer. Methods The prospective study was conducted. The clinicopathological data of 160 patients who underwent thoracoscopic and laparoscopic radical resection of esophageal cancer at the Tumor Hospital Affiliated to Xinjiang Medical University between June 2015 and June 2016 were collected. All the patients undergoing thoracoscopic and laparoscopic radical resection of esophageal cancer were allocated respectively into the experimental group and control group according to the random number table, and intraoperative single-lumen endotracheal tube intubation and continuous CO2 artificial pneumothorax was conducted. Patients in the experimental group received mechanical ventilation using lung protective ventilation strategy. Parameters of mechanical ventilation: tidal volume (VT) 6 mL/kg+ positive end expiratory pressure (PEEP) 5 cmH2O (1 cmH2O=0.098 kPa)+ plat pressure (Pplat)≤30 cmH2O+ recruitment maneuver (RM). Patients in the control group received the traditional ventilation (parameters of ventilation: VT=9 mL/kg). Observation indicators: observation points were at 10 minutes after tracheal intubation in general anesthesia (T1), at 1 hour after one-lung ventilation (T2), at the end of surgery (T3) and at 24 hours postoperatively (T4). (1) Comparison of parameters of respiratory mechanic: peak airway pressure (Ppeak), Pplat and resistance of airway (Raw) . (2) Comparison of the blood gas analysis: arterial oxygen partial pressure (PaO2), arterial carbon dioxide partial pressure (PaCO2) and pH. (3) Comparison of inflammatory reaction indexes: serum IL-6, IL-8, TNF-α and C-reactive protein. (4) Comparison of postoperative pulmonary complications: pulmonary infection, pulmonary atelectasis, pulmonary edema, bronchospasm, hypoxemia and acute respiratory distress syndrome (ARDS). Measurement data with normal distribution were represented as ±s. Comparisons between groups were evaluated with an independent sample t test. Comparisons of count data were done using the chi-square test. Ordinal data were analyzed using the Kruskal-Wallis test. Repeated measurement data were analyzed by the repeated measures ANOVA. Results All the 160 patients were screened for eligibility, 80 in each group. (1) Comparison of parameters of respiratory mechanic: Ppeak, Pplat and Raw from T1 to T3 were respectively from (18.5±3.4)mmHg (1 mmHg=0.133 kPa) to (22.5±4.6)mmHg, from (15.3±3.6)mmHg to (17.5±2.7)mmHg, from (15.1±1.8)cmH2O/(L·s) to (16.8±2.6)cmH2O/(L·s) in the experimental group and from (17.2±3.7)mmHg to (32.5±4.8)mmHg, from (15.1±3.8)mmHg to (21.5±4.5)mmHg, from (15.6±2.8)cmH2O/(L·s) to (19.5±4.0)cmH2O/(L·s) in the control group, with statistically significant differences in the changing trend between the 2 groups (F=10.35, 12.57, 18.63, P<0.05). (2) Comparison of the blood gas analysis: PaO2 from T1 to T4 was from (505±38)mmHg to (490±34)mmHg in the experimental group and from (523±35)mmHg to (460±43)mmHg in the control group, with a statistically significant difference between 2 groups (F=11.56, P<0.05). (3) Comparison of inflammatory reaction indexes: serum IL-6, IL-8, TNF-α and C-reactive protein from T1 to T4 were respectively from (157±35)ng/L to (213±48)ng/L, from (19.3±2.5)ng/L to (21.2±4.3)ng/L, from (158±35)ng/L to (293±46)ng/L, from (7.5±3.5)mg/L to (47.7±5.8)mg/L in the experimental group and from (162±33)ng/L to (326±45)ng/L, from (16.2±3.5)ng/L to (34.2±4.8)ng/L, from (156±35)ng/L to (393±48)ng/L, from (8.6±2.8)mg/L to (78.2±6.5)mg/L in the control group, with statistically significant differences in the changing trend between 2 groups (F=8.85, 10.45, 13.27, 19.68, P<0.05). (4) Comparison of postoperative pulmonary complica-tions: incidence of postoperative pulmonary complications in the experimental group and control group was respectively 17.5%(14/80) and 31.3%(25/80). Pulmonary infection, pulmonary atelectasis, pulmonary edema, bronchospasm, hypoxemia and ARDS were respectively detected in 7, 6, 5, 6, 10, 0 patients in the experimental group and 16, 13, 13, 14, 20, 2 patients in the control group, showing a statistically significant difference between 2 groups (χ2 =4.10, P<0.05). Conclusion Lung protective ventilation strategy can reduce Ppeak and Raw and improve oxygenation in thoracoscopic and laparoscopic radical resection of esophageal cancer, meanwhile, it can also reduce intra- and post-operative inflammatory reaction and postoperative complications. Key words: Esophageal neoplasms; Lung protective ventilation strategy; Pulmonary protection

To evaluate cardiopulmonary effects of one-lung ventilation (OLV) versus two-lung ventilation (TLV) in closed-chest anesthetized dogs. Controlled, randomized experiment. Fourteen, 2- to 7-year-old adult dogs, weighing 23 +/- 6 kg. The dogs were anesthetized with acepromazine, morphine, thiopental, and halothane in oxygen, ventilated, and paralyzed with vecuronium. Tidal volume was 10 mL/kg. Respiratory rate was set to maintain end-tidal CO2 (ETCO2) at 40 +/- 2 mm Hg before instrumentation then not changed. The left bronchus of 7 dogs was obstructed with a Univent bronchial blocker (Fuji Systems Corp, Tokyo, Japan). Blood gas analysis and hemodynamic measurements were taken at predetermined intervals for 1 hour in the TLV group and at baseline and following bronchial obstruction in the OLV group. Shunt fraction was not significantly different between groups, but in OLV shunt increased from baseline at 5 minutes. Arterial oxygen (PaO2) decreased after baseline in OLV compared with TLV. Arterial carbon dioxide (PaCO2) increased with OLV and decreased with TLV. In OLV, systemic vascular resistance was variable and decreased compared with TLV. Cardiac index increased over time in both groups but was not affected by treatment. Heart rate, mean arterial pressure, and diastolic arterial pressure increased with OLV compared with TLV but did not change over time. This study shows that OLV statistically decreases oxygen tension and transiently increases shunt fraction, but with 100% O2 it appears to be a feasible procedure with minimal cardiopulmonary side effects in healthy dogs. OLV is a feasible procedure in anesthetized dogs to better facilitate thoracic procedures such as bronchopleural fistula repair and thoracoscopy.

Mathematical simulation of pulmonary O 2 and CO 2 exchange.