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PubMedDate not supplied

Carbon dioxide embolism during laparoscopy: effect of insufflation pressure in pigs.

Carbon dioxide embolism is a rare but potentially devastating complication of laparoscopy. To determine the effects of insufflation pressure on the mortality from carbon dioxide embolism, six swine had intravascular insufflation with carbon dioxide for 30 seconds using a Karl Storz insufflator at a flow rate of 35 mL/kg/min. The initial insufflation pressure was 15 mm Hg. Following recovery from the first embolism, intravascular insufflation using a pressure of 20 mm Hg at the same flow rate was performed in the surviving animals. Significantly less carbon dioxide (8.3 +/- 2.7 versus 16.7 +/- 3.9 mL/kg; p < 0.02) was insufflated intravascularly at 15 mm Hg than at 20 mm Hg pressure. All of the pigs insufflated at 15 mm Hg pressure with a flow rate of 35 mL/kg/min survived. In contrast, 4 of the 5 pigs insufflated at 20 mm Hg pressure died. The surviving pig died when insufflated with 25 mm Hg pressure following an embolism of 15.7 mL/kg. Intravascular injection was often associated with an initial rise in end-tidal carbon dioxide tension, followed by a rapid fall in all cases where the embolism proved fatal. Insufflation should be begun with a low pressure and a slow flow rate to limit the volume of gas embolized in the event of inadvertent venous cannulation. Insufflation should immediately be stopped if a sudden change in end-tidal carbon dioxide tension occurs.

Animals↗

PubMedDate not supplied

The accuracy of gastric insufflation in testing for gastroesophageal perforations during laparoscopic Nissen fundoplication.

BACKGROUND: Laparoscopic Nissen fundoplication is an effective technique for the symptomatic relief of the manifestations of gastroesophageal reflux disorder but is associated with a 0.8-1% rate of gastroesophageal perforation. Early detection and repair of these injuries is critical to patient outcome, but occult injuries occur and may be missed. Gastric insufflation technique evaluates the integrity of the gastroesophageal wall after laparoscopic Nissen fundoplication. Gastric insufflation technique involves occlusion of the proximal stomach with a noncrushing bowel clamp while insufflating the submerged gastroesophageal junction. We conducted an animal study to assess the utility of gastric insufflation technique. METHODS: Five pigs (mean weight, 40.4 kg) underwent testing of laparoscopic gastric insufflation technique. In four animals, laparoscopic Nissen fundoplication was performed and then gastroesophageal junction injuries were created (3-5 mm distraction-type wall injuries). Non-crushing bowel clamps provided occlusion of the pylorus and then the proximal stomach during gastroesophageal insufflation. The gastroesophageal junction was then submerged. In the fifth animal, gastric insufflation technique was repeated while calibrated injuries were created to determine the smallest detectable injury. An injury was considered detectable if rising air bubbles were noted from the submerged gastroesophageal structures. Maximal luminal pressures needed to detect injuries were recorded with an in-line manometer. RESULTS: In all animals, 5-7 mm injuries of the gastroesophageal junction were easily detected using gastric insufflation technique when the proximal stomach was occluded. When the pylorus alone was occluded, detection of gastroesophageal injuries was inconsistent. Small injuries (<3 mm) of the esophagus were difficult to visualize with pyloric occlusion alone but were consistently detectable with proximal stomach occlusion at pressures less than 20 mm Hg. When the pylorus alone was occluded, the smallest detectable stomach perforation was a 16-gauge needle puncture while applying maximal gastric pressure (40-60 mm Hg) and a 2.5 mm linear injury when generating lower pressures (20 mm Hg). CONCLUSION: Proximal stomach occlusion and insufflation appears to effectively detect esophageal injuries of likely clinical importance (>2.5 mm). Pyloric occlusion and insufflation reliably evaluates the anterior stomach for injury. Gastric insufflation technique is a useful method for detecting gastroesophageal injury after laparoscopic Nissen fundoplication.

Animals↗

PubMed2000

Intraperitoneal and retroperitoneal carbon dioxide insufflation evoke different effects on caval vein pressure gradients in humans: evidence for the starling resistor concept of abdominal venous return.

BACKGROUND: The authors hypothesized that intraperitoneal and retroperitoneal carbon dioxide insufflation during surgical procedures evoke markedly different effects on the venous low-pressure system, induce different inferior caval vein pressure gradients at similar insufflation pressures, and may provide evidence for the Starling resistor concept of abdominal venous return. METHODS: Intra- and extrathoracic caval vein pressures were measured using micromanometers during carbon dioxide insufflation at six cavity pressures (baseline and 10, 15, 20, and 24 mmHg and desufflation) in 20 anesthetized patients undergoing laparoscopic (supine, n = 8) or left (n = 6) or right (n = 6) retroperitoneoscopic (prone position) surgery. Intracavital, esophageal, and gastric pressures also were assessed. Data were analyzed for insufflation pressure-dependent and group effects by one-way and two-way analysis of variance for repeated measurements, respectively, followed by the Newman-Keuls post hoc test (P < 0.05). RESULTS: Intraperitoneal, unlike retroperitoneal, insufflation markedly increased, in an insufflation pressure-dependent fashion, the inferior-to-superior caval vein pressure gradient (P < 0.00001) at the level of the diaphragm. In contrast to what was observed with retroperitoneal insufflation, transmural intrathoracic caval vein pressure increased at 10 mmHg insufflation pressure, but the increase flattened with an insufflation pressure of more than 10 mmHg, and pressure decreased with an inflation pressure of 20 mmHg (P = 0.0397). These data are consistent with a zone 2 or 3 abdominal vascular condition during intraperitoneal and a zone 3 abdominal vascular condition during retroperitoneal insufflation. CONCLUSIONS: Intraperitoneal but not retroperitoneal carbon dioxide insufflation evokes a transition of the abdominal venous compartment from a zone 3 to a zone 2 condition, presumably impairing venous return, supporting the Starling resistor concept of abdominal venous return in humans.

Anesthesia, Inhalation↗

PubMed1981

A murine model for multiple laparoscopies: I. Early lymphoid response to intraperitoneal insufflation of CO2.

In a model for multiple laparoscopies proliferation of T-lymphocytes was an early, but transitory, immunologic reaction in the spleen to intraperitoneal CO2 insufflation. Intraperitoneal insufflations of approximately 3.5 ml of CO2 were given daily to three groups of BALB/c mice for 11, 20, and 32 consecutive days, respectively. Air insufflation was given to experimental controls. The observations in the insufflation model are summarized as follows: 1) Multiple CO2 insufflation approximately doubled the number of splenic T lymphocytes. 2) The percentage value was highest on the day of the last insufflation. The difference between this value in each of the three groups was statistically not significant; ie, there was no dose-response relationship in the range of 11-32 insufflations. 3) There was a dose-response effect in the range of 3-9 insufflations. 4) The number of splenic T lymphocytes decreased with each day after the end of treatment. Untreated control values were reached in 12-16 days. 5) Air insufflation had only a minimal effect on the proliferation of T lymphocytes in the spleen. In this model there is correlation between early proliferation of T lymphocytes in the spleen and the late occurrence of a high incidence of malignant lymphoma (approximately 60%). The long-term survivors of CO2 insufflation also developed a wide spectrum of intraabdominal malignancies. It was speculated that CO2 insufflation provided an abnormal internal environment that affected a variety of target tissues. Prolonged CO2 accumulation might have modified nucleic acid structure via chronic intracellular acidosis. Could the neoplastic sequelae in this model be a clue to a similar sequel in humans after multiple laparoscopies?

Animals↗

PubMed1997

Risk of contamination from laparoscopic carbon dioxide insufflators.

Ten high flow laparoscopic carbon dioxides insufflators were examined to determine whether there was significant particulate or bacterial contamination of the gas delivered to patients. The gas delivery tubing and connections in the insufflators were also examined for the presence of bacterial colonization and for evidence of retrograde passage of body fluids to the insufflator. Metallic particulate debris was recovered from gas from all 10 insufflators. Staphylococci were recovered from the insufflated gas from one insufflator and from the internal tubing of three insufflators. Swabs from the internal tubing of two insufflators showed evidence of contamination by blood. The metallic particulate contamination of the insufflated gas may not be of clinical significance but the presence of bacteria and blood is a concern. Simple measures to minimize the risk of retrograde flow of gas and fluid to the insufflator should be followed and the provision of a filter between the patient and the insufflator is recommended.

Carbon Dioxide↗

PubMed2005

A versatile dual-channel carbon dioxide (CO2) insufflator for various CO2)applications. The prototype.

BACKGROUND: Carbon dioxide (CO2), with its rapid absorptive nature, has been proven superior to atmospheric air as an insufflating agent in various clinical settings. However, CO2 insufflation has not gained wide clinical acceptance, mainly because there has been no suitable feeding system. The authors therefore have developed a versatile "dual-channel" CO2 insufflator that facilitates wider use of CO2. The objectives of this study were to introduce the authors' prototype insufflator, to evaluate its safety and performance, and to validate CO2 application using the prototype. METHODS: The prototype insufflator provides one CO2 inlet connected to a regular CO2 gas cylinder and two CO2 outlets positioned on the front and back of the device, respectively. The CO2 gas fed from the cylinder is pressure-regulated and divided into two independent conduits inside the device. The front outlet feeds CO2 gas for pneumoperitoneum at an electronically controlled pressure and flow rate. The back channel supplies CO2 gas at a fixed flow rate, allowing manual control of insufflation for various purposes. The device was evaluated with canine models. RESULTS: The prototype was safe and performed well. The CO2 application (colonoscopy in this series) using the back channel was feasible while intact CO2 pneumoperitoneum was simultaneously maintained via the front channel. There were no device malfunctions. The serial abdominal x-rays indicated that intraluminal CO2 insufflation such as that used for CO2 colonoscopy caused less residual intestinal gas than conventional air insufflation. CONCLUSIONS: The dual-channel CO2 insufflator enabled two different modes of CO2 insufflation at the same time from a single CO2 cylinder. The authors are now improving the prototype to allow safer and wider usage of CO2 in the operating room.

Animals↗

PubMed1999

Humidified gas prevents hypothermia induced by laparoscopic insufflation: a randomized controlled study in a pig model.

BACKGROUND: This experimental study evaluated whether humidification of warmed insufflated CO2 during laparoscopic procedures would resolve the problem of laparoscopy-induced hypothermia. METHODS: Changes in core temperature were quantified over a 3-h period of high-flow CO2 insufflation in a randomized, controlled trial of five pigs. Each animal was anesthetized and studied on three occasions under standardized conditions, acting as its own control by insufflation with no gas compared with insufflation by cool dry gas and heated humidified gas. RESULTS: Core temperatures after insufflation with heated humidified gas were no different from that of controls. After insufflation with cool dry gas, core temperature dropped by 1.8 degreesC, which was significantly more than the 0.6 degreesC drop experienced by control animals and those insufflated with heated humidified gas (p < 0.01). Calculations of the heat expended in evaporation of water were also performed. The temperature drop due to water evaporation alone in pigs insufflated with cool dry gas was calculated to be 1.5 degreesC. This compares favorably with the measured 1.2 degreesC temperature difference between these animals and the control group. CONCLUSIONS: The majority of heat lost during laparoscopic insufflation is due to water evaporation, and laparoscopic hypothermia may be prevented by using heated and humidified gas insufflation.

Analysis of Variance↗

PubMed1995

Intraperitoneal versus extraperitoneal insufflation of carbon dioxide as for laparoscopy.

In order to compare the effects of intraperitoneal and extraperitoneal insufflation of CO2, we obtained blood gas measurements and chest radiographs in dogs during insufflation into three sites: the peritoneal cavity alone, the retroperitoneal space with communication into the peritoneal cavity, and the retroperitoneal space alone. The blood pH fell a mean of 0.11 +/- 0.03 and the PaCO2 rose a mean of 16.0 +/- 3.7 mm Hg when insufflation included the peritoneal cavity, whereas when insufflation was limited to the retroperitoneum, the pH fell a mean of 0.05 +/- 0.03 and the PaCO2 rose a mean of 7.5 +/- 2.8 mm Hg. Extrapleural thoracic dissection of gas was noted in one animal after insufflation limited to the retroperitoneal space. These findings confirm that there is significant absorption of CO2 from the peritoneal cavity during laparoscopy with CO2 insufflation, whether the pneumoperitoneum is primary or occurs secondary to retroperitoneal insufflation. If the insufflated gas is limited to the retroperitoneal space, however, the absorption of CO2 appears to be reduced in this animal model. The risk of thoracic dissection of gas may be greater during extraperitoneal insufflation than during intraperitoneal insufflation.

Absorption↗

PubMed1996

Intraabdominal carbon dioxide insufflation in the pregnant ewe. Uterine blood flow, intraamniotic pressure, and cardiopulmonary effects.

BACKGROUND: Laparoscopic surgical procedures are being performed in pregnant women with increasing frequency. Maternal-fetal physiologic changes occurring during intraabdominal carbon dioxide insufflation are poorly understood, and maternal-fetal safety is of concern during carbon dioxide pneumoperitoneum. A previous pilot study using end-tidal carbon dioxide-guided ventilation resulted in maternal and fetal acidosis and tachycardia during carbon dioxide pneumoperitoneum. Using serial arterial PCO2 to guide ventilation, this study was designed to evaluate maternal-fetal cardiopulmonary status, uterine blood flow, and the intraamniotic pressure effects of intraabdominal carbon dioxide insufflation in singleton pregnant ewes between 120 and 135 days of gestation. METHODS: In a prospective randomized cross-over study, nine ewes were to receive either abdominal insufflation with carbon dioxide to an intraabdominal pressure of 15 mmHg (n = 9; insufflation group) or receive no insufflation (n = 9; control group). Anesthesia was induced with thiopental and maintained with end-tidal halothane (1 to 1.5 minimum alveolar concentration/100% oxygen). Mechanical ventilation was guided by serial maternal arterial blood gas analysis to maintain PaCO2 between 35 and 40 mmHg. Data from insufflated animals were collected during insufflation (60 min) and after desufflation (30 min). Control group data were collected and matched to similar time intervals for 90 min. Ewes were allowed to recover, and after a rest period (48 h) they were entered in the cross-over study. RESULTS: During insufflation there was a significant increase (P < 0.05) in maternal PaCO2 to end-tidal carbon dioxide gradient and minute ventilation, with concomitant decreases in maternal end-tidal carbon dioxide and PaO2. Intraamniotic pressure increased significantly during insufflation. No significant changes were observed in maternal hemodynamic variables, fetal variables, or in uterine blood flow during the study. There were no fetal deaths or preterm labor in any of the animals during the experiment. CONCLUSIONS: During the 1-h insufflation, a marked increase in PaCO2-to-end-tidal carbon dioxide gradient was observed, suggesting that capnography may be an inadequate guide to ventilation during carbon dioxide pneumoperitoneum in the pregnant patient. No other significant circulatory changes were observed.

Amnion↗

PubMed2006

Insufflation techniques in gynecologic laparoscopy.

Our objectives were to assess the safety and efficacy of different insufflation methods in women undergoing laparoscopy and to develop a model for selection of the appropriate insufflation technique based on the patient's characteristics and surgeon's experience. We performed a retrospective analysis of laparoscopic procedures on 3086 women over a 13-year period at the University of Louisville Hospital, Louisville, KY. All laparoscopic procedures were performed on an outpatient basis by residents under faculty supervision. Five different insufflation techniques were evaluated: standard transumbilical insufflation, open laparoscopy, transuterine insufflation, subcostal insufflation, and direct trocar insertion technique. Body mass index and previous abdominal surgeries were identified as the most important factors in the selection of the most successful insufflation method based on the surgeon's experience, using data mining techniques. During the first insufflation attempt, we were successful at achieving a pneumoperitoneum 94.7% of the time. This number increased to 98.1% when we switched to a second alternative insufflation method. In all, there were 5 complications out of 3086 patients (0.16%) after all insufflation techniques.

Adolescent↗

PubMed1997

Hemodynamics during laparoscopic extra- and intraperitoneal insufflation. An experimental study.

BACKGROUND: Total extraperitoneal laparoscopic surgery is an alternative to the laparoscopic transperitoneal route; however, its effects on hemodynamics have not been adequately studied. This experimental study compared the effects of intraperitoneal insufflation and extraperitoneal insufflation on hemodynamics and oxygen transport. METHODS: Sixteen pigs were randomly assigned for intraperitoneal insufflation or extraperitoneal insufflation with 15 mmHg carbon dioxide. Hemodynamic and oxygen transport parameters were taken during an hour of insufflation and analyzed for statistical differences. RESULTS: During extraperitoneal CO2 pneumoperitoneum central venous filling pressures (central venous pressure, pulmonary capillary wedge pressure and mean pulmonary arterial pressure) and end-tidal CO2 increased slower but to a similar magnitude in comparison to intraperitoneal insufflation. Cardiac output and indices of oxygen consumption and oxygen delivery were equally affected by both types of insufflation. Arterial CO2 pressure increased significantly more during intraperitoneal insufflation. CONCLUSION: The data from this study suggest that extraperitoneal insufflation might result in less cardiovascular impairment than intraperitoneal insufflation.

Analysis of Variance↗

PubMed1998

Femoral venous flow dynamics during intraperitoneal and preperitoneal laparoscopic insufflation.

BACKGROUND: Laparoscopic herniorrhaphy may be performed using an intraperitoneal or a preperitoneal approach. Anecdotal and experimental evidence indicates that alterations in lower extremity venous flow, which occur during intraperitoneal laparoscopic insufflation, may be associated with an increased risk of deep vein thrombosis. However, no study has directly compared femoral venous flow during intraperitoneal insufflation with that during preperitoneal insufflation. METHOD: In eight consecutive patients undergoing laparoscopic herniorrhaphy under general anesthesia, flow through the common femoral vein was evaluated with B-mode and color flow duplex. Pre- and intraperitoneal pressures were standardized to 10 mm Hg, and respiratory tidal volumes were standardized to 10 cc/kg. Flow measurements were taken at end expiration. Flow through the common femoral vein was measured after induction of anesthesia, during intraperitoneal insufflation, during preperitoneal insufflation, and between insufflations to ensure return to baseline. RESULTS: All patients in the study were males. Their mean age was 59 years. Mean flow in the common femoral vein was essentially identical at baseline (138 ml/min) and during preperitoneal insufflation (135 ml/min). Alternatively, mean flow in the common femoral vein was significantly reduced during intraperitoneal insufflation (65 ml/min, p = 0.02). CONCLUSIONS: Flow in the common femoral vein is significantly reduced during intraperitoneal insufflation. However, flow in the common femoral vein is not affected by preperitoneal insufflation. These data suggest that laparoscopic preperitoneal inguinal hernia repair may pose as less a risk of thromboembolic complications than laparoscopic intraperitoneal inguinal hernia repair.

Adult↗

PubMed1999

The effects of retroperitoneal carbon dioxide insufflation on hemodynamics and arterial carbon dioxide.

BACKGROUND: Laparoscopic techniques are being increasingly used for retroperitoneal surgery. However, hemodynamic and ventilatory efforts of retroperitoneal carbon dioxide (CO2) insufflation have not been studied. We hypothesized that differences in absorptive surface, anatomy, and compartment compliance could result in different hemodynamic and ventilatory effects between retroperitoneal and intraperitoneal insufflation. METHODS: Pigs (n = 7) were anesthetized and stabilized. The peritoneal cavity was incrementally insufflated with CO2 to a maximum pressure of 25 cm H2O and the gas released. Hemodynamics and arterial blood gas values were recorded initially, at each level of insufflation, and following the pneumoperitoneum release until baseline values were reached. This insufflation protocol was repeated in the retroperitoneum. RESULTS: Mean arterial pressure (111 mm Hg, 95% confidence interval 99 to 156) and cardiac output (3.7 L/min, 2.8 to 5.2) did not change with increasing insufflation pressure of either intraperitoneum or retroperitoneum. PaCO2 was directly related to insufflation pressure in both spaces, increasing from 41.2 mm Hg (37.3 to 43.4) at baseline to 57.7 mm Hg (47.6 to 82.1) at insufflation pressure of 25 cm H2O. After release of the insufflation gas, time to return to baseline PaCO2 was slightly less from the retroperitoneal space (73 minutes, 45 to 105) than the intraperitoneal (107 minutes, 35 to 175). CONCLUSIONS: The effects of CO2 insufflation on hemodynamics and PaCO2 are the same in the retroperitoneal and intraperitoneal spaces.

Animals↗

PubMed2003

Tumor implantation during laparoscopy using different insufflation gases - an experimental study using cultured cancer cells.

Recent work using an experimental model in our laboratory has shown that the likelihood of tumor implantation at laparoscopy port-sites following laparoscopy might be influenced by the specific gas used for insufflation. In particular helium insufflation was associated with less port site metastases. The model entailed an inbred rat strain and a tumor cell suspension of mixed heterogeneity, native to the rat strain. To determine whether our previous findings could be reproduced using a different model, we investigated the effect of insufflation with either helium or carbon dioxide gas on the implantation of a purified cell suspension of cultured cancer cells. Thirty-eight Dark Agouti rats were randomized to undergo a 40 minute period of laparoscopic insufflation with either helium or carbon dioxide (19 animals in each group/three different experiments). Three laparoscopy ports were placed and 2 x 10 5 cultured mammary adenocarcinoma cells were introduced into the abdominal cavity at the beginning of the period of insufflation. The rats were killed nine days after surgery and the port sites and abdominal cavity were examined for presence of tumor. Rats undergoing helium insufflation were equally likely to develop port-site metastases compared to rats undergoing carbon dioxide insufflation. There was, however, a predilection for port site metastases to develop at the port site used for camera placement in both groups. Because this port site accommodated a 2 mm laparoscope, it was associated with a larger wound than the other two port sites. Peritoneal tumor deposits elsewhere in the peritoneal cavity were more common following helium insufflation, compared to carbon dioxide. The outcome of this study is different to the results from previous studies using a heterogeneous tumor cell suspension in the same model in our laboratory, or elsewhere, with no advantages demonstrated for insufflation with helium gas. Purified cell suspensions could behave differently to a heterogeneous cell suspension of identical cancer cells in a port-site implantation model, and other cells present within heterogeneous tumor suspension might influence the likelihood of metastasis. As reported previously, tumor implantation is more likely in larger port site wounds and this is independent of the insufflation gas.

Journal Article↗

PubMed1975

Cardiovascular effects of intraperitoneal insufflation with carbon dioxide and nitrous oxide in the dog.

Cardiovascular changes caused by intraperitoneal insufflation with CO2 or N2O were measured in 15 mongrel dogs. Moderate progressive increases in intra-abdominal pressure (to 40 mm Hg) with either gas produced increases in mean arterial, right atrial, pleural, and femoral-vein pressures. Cardiac output and inferior vena caval flow were momentarily increased following the commencement of insufflation. However, both flows decreased precipitously as insufflation pressure was increased. At an intra-abdominal pressure of 40 mm Hg cardiac output and inferior vena caval flow were reduced more than 60 per cent in most cases. Peripheral resistance increased by approximately 200 per cent. Upon sudden release of abdominal pressure cardiac output and inferior vana caval flow increased but then returned to pre-insufflation values within seconds. Directly measured right atrial pressure increased with increasing insufflation pressure, but calculated transmural right atrial pressure decreased with the increase in intra-abdominal pressure. Insufflation with CO2 produced significant increases in PaCO2. However, cardiostimulatory effects due to elevated blood CO2 levels were not seen. The data from this study indicate that intraperitoneal insufflation produces serious hemodynamic alterations which are manifested by low cardiac output and elevated total peripheral resistance. In addition, directly measured right atrial pressure cannot be used clinically as an indicator of venous return to the heart since it reflects a composite of pleural and intra-abdominal insufflation pressure. (Key words: Anesthetics, gases, nitrous oxide; Carbon dioxide, intraperitoneal; Surgery, intraperitoneal insufflation; Heart, function, intraperitoneal insufflation.).

Acid-Base Equilibrium↗

PubMed1995

Effect of tracheal gas insufflation on gas exchange in canine oleic acid-induced lung injury.

OBJECTIVE: To determine the effect of tracheal gas insufflation on gas exchange in oleic acid-induced lung injury in dogs. DESIGN: Prospective, longitudinal study. SETTING: University research laboratory. SUBJECTS: Five mongrel dogs. INTERVENTIONS: The dogs were anesthetized, paralyzed, and mechanically ventilated. Lung injury was induced by infusing 0.09 mL/kg of oleic acid and pulmonary artery occlusion (wedge) pressure (PAOP) was increased to 15 mm Hg by infusing fluids to enhance pulmonary edema formation. After 60 mins, PAOP was allowed to decrease to 5 mm Hg and was maintained at 5 mm Hg for 60 mins to stabilize the pulmonary edema. We studied the effect of tracheal gas insufflation on gas exchange at low and high end-expiratory lung volumes achieved by a positive end-expiratory pressure of 5 and 12 cm H2O, respectively. The FIO2 values of the ventilator and catheter were equivalent (0.6). Each tracheal gas insufflation stage at low and high end-expiratory lung volume was preceded and followed by conventional mechanical ventilation stages without tracheal gas insufflation. During transitions between conventional mechanical ventilation and tracheal gas insufflation, end-expiratory lung volume was maintained constant by adjusting positive end-expiratory pressure while monitoring esophageal pressure and inductive plethysmography. Tidal volume was maintained constant throughout the protocol (0.40 L). MEASUREMENTS AND MAIN RESULTS. At end stage, we measured PaCO2, PaO2, total physiologic deadspace fraction, and venous admixture, which were 43 +/- 4 torr (5.7 +/- 0.5 kPa), 325 +/- 6 torr (43.3 +/- 0.8 kPa), 53 +/- 3%, and 4.0 +/- 0.3% before oleic acid lung injury, respectively. After oleic acid injury at low end-expiratory lung volume, these variables were 55 +/- 4 torr (7.3 +/- 0.5 kPa), 73 +/- 13 torr (9.7 +/- 1.7 kPa), 61 +/- 4%, and 50 +/- 7%, respectively. During tracheal gas insufflation at low end-expiratory lung volume conditions, PaCO2 and the total physiologic deadspace fraction decreased significantly (p < .05) to 45 +/- 4 torr (6.0 +/- 0.5 kPa) and 50 +/- 5%, respectively. Under high end-expiratory lung volume conditions, PaCO2 and the total physiologic deadspace fraction were 55 +/- 7 torr (7.3 +/- 0.9 kPa) and 61 +/- 6%, respectively; during tracheal gas insufflation, these variables decreased to 43 +/- 4 torr (5.7 +/- 0.5 kPa) and 52 +/- 5%, respectively (p < .05). Increasing end-expiratory lung volume improved both PaO2 and venous admixture (p < .05) but tracheal gas insufflation had no significant effect on oxygenation efficiency when end-expiratory lung volume was held constant. CONCLUSIONS: Tracheal gas insufflation augmented alveolar ventilation effectively in the setting of oleic acid-induced lung injury in dogs. When end-expiratory lung volume and tidal volume were kept constant, tracheal gas insufflation did not affect oxygenation.

Animals↗

PubMed2006

[The effect of cervical gas insufflation on metabolic and hemodynamic during endoscopic neck surgery].

OBJECTIVE: Carbon dioxide and helium were insufflated into the neck of rabbits to investigate the effect of different levels of insufflation pressure and duration on metabolic and hemodynamic changes. METHOD: Fifteen New Zealand rabbits were randomly divided into 5 groups: 5 mmHg CO2, 10 mmHg CO2, 15 mmHg CO2, 15 mmHg He and 0 mmHg. Arterial partial pressure of CO2 (PaCO2), pH, heart rate (HR), mean arterial pressure (MAP) and central venous pressure (CVP) were measured at baseline, 45 min and 90 min after gas insufflation and 30 min after desufflation. RESULT: Insufflation of CO2 at 5 mmHg had not any significant effect on the parameters. PaCO2 increased significantly 45 min and 90 min after CO2 insufflation at 10 mmHg (P < 0.05). Marked changes in PaCO2, pH and CVP occurred 45 min and 90 min after CO2 insufflation at 15 mmHg (P < 0.05), and the parameters did not return to baseline 30 min after desufflation. In animals receiving He insufflation at 15 mmHg, CVP increased significantly after 90 min (P < 0.05), and the parameters returned to baseline 30 min after desufflation. Animals receiving He insufflation did not experience hypercapnia. No significant changes in HR and MAP occurred in all animals. CONCLUSION: Carbon dioxide insufflation for endoscopic neck surgery is safe below 10 mmHg. When higher pressure is required, the level lower than 15 mmHg is recommended and the insufflation duration should be limited. The use of He should be careful due to the low solubility.

Animals↗

PubMed1982

One-lung anesthesia: percent shunt and arterial oxygen tension during continuous insufflation of oxygen to the nonventilated lung.

Twenty-four male patients scheduled for elective pulmonary resection were studied to determine whether continuous insufflation of oxygen to the nonventilated lung would reduce intrapulmonary shunting (Qs/Qt) and arterial oxygen desaturation. Measurements of physiologic variables were made using pulmonary arterial and peripheral arterial catheters. Blood was sampled for analysis and Qs/Qt and other hemodynamic variables were calculated. Significant differences were observed in Qs/Qt and arterial oxygen tensions (PaO2) between patients insufflated and those in whom oxygen was not insufflated. Patients with oxygen insufflation had significantly lower Qs/Qt and consistently higher PaO2. Statistically significant differences in Qs/Qt became apparent after 15, 30, and 45 minutes of one-lung ventilation compared with values for patients not receiving oxygen insufflation. Six of 12 patients without oxygen insufflation had peak Qs/Qt levels greater than 50%, whereas none of the patients in whom oxygen was insufflated had levels that exceeded this amount. Of 12 patients given oxygen insufflation, one had a PaO2 of less than 100 torr at the point of maximum decrease in arterial oxygen tension, compared with six of 12 patients in whom oxygen was not insufflated. These findings suggest that continuous oxygen insufflation of the nonventilated lung during periods of one-lung ventilation reduces Qs/Qt and minimizes arterial oxygen desaturation.

Adult↗