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Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypercarbia occurs during laparoscopy with carbon dioxide (CO2) insufflation. This may be due to increased ventilatory dead space after expansion of the peritoneal cavity with impairment of diaphragmatic excursion, or to increased absorption of CO2 from the peritoneum. To separate these effects, the authors examined the consequences of different insufflating gases and of diminished tissue perfusion on hypercarbia and dead space during pneumoperitoneum. Helium was chosen as an alternate insufflating gas because it is both inert and minimally absorbed. Eight swine (18 to 20 kg) were anesthetized, paralyzed, and mechanically ventilated at constant minute volume. Pneumoperitoneum with helium was maintained at 15 mm Hg for 45 minutes. After desufflation and stabilization for 1 hour, pneumoperitoneum was repeated with CO2. The sequence was again repeated after hemorrhagic shock to constant mean arterial pressure of 50 mm Hg. Data was analyzed by analysis of variance; significance levels are P < 0.01 unless otherwise listed. Arterial PCO2 increased significantly with CO2 insufflation within 15 minutes in normotensive animals and within 30 minutes during hypotension. Arterial pH decrease with CO2 pneumoperitoneum was significant in both groups at 30 minutes. Mixed venous PCO2 also increased with CO2 pneumoperitoneum within 30 minutes. Hypotension did not alter these changes. No significant changes were seen with helium pneumoperitoneum. Neither helium nor CO2 pneumoperitoneum significantly altered dead space. The authors make the following conclusions: 1) Absorption of CO2 from the abdomen during CO2 pneumoperitoneum produces respiratory acidosis, which is not seen with helium insufflation; 2) Pneumoperitoneum does not significantly increase dead space with either gas; 3) Transperitoneal absorption of CO2 is only partly related to perfusion because significant hypercarbia occurs during hemorrhagic shock.
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PMID:Effectors of hypercarbia during experimental pneumoperitoneum. 145 92

We study gas exchange and hemodynamic repercussions during pediatric laparoscopic surgery. We provided balanced anesthesia with muscle relaxation while ventilation was maintained with FiO2 at 0.4 and flow volume between 10-15 ml/kg-1 during abdominal laparoscopic procedures performed in 10 ASA I-II children (4-14 years). Pneumoperitoneum was produced with CO2 insufflated up to a pressure of 15 mmHg. Airways pressure (PIP), PaO2, PaCO2, heart rate (HR), systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) were measured before insufflation and 5, 30 and 60 minutes afterwards. We calculated the ratio of dead space to flow volume (VD/VT), thoracic distensibility and metabolic production of CO2 (VCO2). Insufflation caused an immediate reduction (29-33%) in dynamic thoracic distensibility (p = 0.0004), but no hypoventilation or increases in VD/VT. The decrease in PaO2 was small (5-6%) but statistically significant (p = 0.0188). Hypercapnia (14-21%) was due to an increase in VCO2 caused by gradual peritoneal absorption of CO2 (24-32%, p = 0.0013). We also found increases in SAP (10%, p = 0.02) and DAP (32%, p = 0.0001) at 5 min, along with an increase in HR (8%, p = 0.0163) at 60 min. Arterial CO2 levels were held within physiological limits by compensatory hyperventilation (+25% of physiological VT). Capnography proved to be an excellent guide. Any clinical repercussion of hemodynamic effects was blocked by a dose of atropine given before insufflation and by the excess loading volume (10 ml/kg of crystalloids). Laparascopic surgery in children diminishes thoracic distensibility and causes hypercapnia, making it necessary to measure PefCO2 to regulate ventilation.
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PMID:[Physiopathologic implications of the anesthesiologic management of pediatric laparoscopic surgery]. 748 Oct 25

Controversy has been raised about the effects of systemic carbon dioxide accumulation versus the intra-abdominal pressure on hemodynamics during laparoscopy. We compared the acid-base and hemodynamic changes during pneumoperitoneum in a randomized cross-over study between CO2 and nitrogen gases to test the hypothesis that the CO2 absorbed during laparoscopy, rather than the 15 mmHg intra-abdominal pressure created, accounted for these changes. Eight adult pigs were anesthetized and ventilated with a fixed minute ventilation. Metabolic function was measured from analysis of expired flow by a metabolic measurement cart. After baseline periods, animals were randomized into two groups, for 2 hr of either CO2 or nitrogen pneumoperitoneum at 15 mmHg intra-abdominal pressure, followed by 1 hr of recovery. After at least a 48-hr recovery period, the experiment was repeated with the other gas. Metabolic data revealed that there was a significant absorption of CO2 gas across the peritoneal epithelium during CO2 pneumoperitoneum. Animals insufflated with CO2 gas experienced a 75% increase in pulmonary CO2 excretion, with significant acidemia and hypercapnia, whereas there were no acid-base disturbances in those with nitrogen insufflation. Oxygen consumption remained essentially unchanged in both groups, even during pneumoperitoneum. CO2 pneumoperitoneum was also associated with systemic and pulmonary arterial hypertension and a reduction in stroke volume of up to 15%. Pneumoperitoneum alone did not compromise hemodynamics. Pneumoperitoneum using CO2 gas during laparoscopy resulted in systemic CO2 absorption across the peritoneum. This led to acidemia, hypercapnea, and depressed hemodynamics. The intra-abdominal pressure routinely used during laparoscopic surgery did not affect metabolic function, acid-base balance, or hemodynamics in the experimental model.
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PMID:Effector of hemodynamics during laparoscopy: CO2 absorption or intra-abdominal pressure? 756 24

Pneumoperitoneum with CO2 is associated with adverse effects, such as hypercarbia, arrhythmias, and circulatory depression, which may limit its use in patients with underlying disease. Some of these effects may be caused by CO2 absorption resulting in acid-base disturbances. Laparoscopic insufflation with helium may be a good alternative for CO2, since it is chemically inert. Because there are few data on the use of helium for laparoscopy, we studied hemodynamics and gas exchange during insufflation with CO2 or helium in 8 pigs at 10, 15, and 20 mm Hg intraabdominal pressure. Heart rate did not change significantly with both gases. Arterial blood pressure increased with CO2 (p < 0.05) but not with helium. Cardiac output, mixed venous oxygen saturation, and oxygen consumption did not decrease, whereas central venous filling pressures increased during insufflation with either gas. Insufflation with CO2 resulted in mild increases in arterial, central venous, and end-expiratory CO2. The results suggest that pneumoperitoneum with helium will not be associated with profound circulatory depression or oxygen transport abnormalities. In addition, the use of helium is not associated with acid-base disturbances, although central venous filling pressures are similarly increased as with the use of CO2 pneumoperitoneum.
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PMID:Effects of pneumoperitoneum with helium on hemodynamics and oxygen transport: a comparison with carbon dioxide. 776 23

The effects of pneumoperitoneum with carbon dioxide and helium on systemic hemodynamics and arterial blood gases were investigated in pigs in an attempt to clarify the mechanisms by which pneumoperitoneum may induce organ dysfunction. A total of 16 anesthetized female pigs underwent pneumoperitoneum with carbon dioxide or helium (n = 8 each) in a stepwise fashion to intraabdominal pressures of 8, 10, 12, 16, and 20 mmHg. Changes in cardiac output; renal and hepatic blood flow; mean arterial, mean pulmonary arterial, mean pulmonary arterial wedge, inferior vena caval, and portal venous pressures; and total peripheral resistance were measured. Arterial blood samples were obtained at the same time the above parameters were determined. Urine volume was measured as an indicator of renal function. Pneumoperitoneum with either carbon dioxide or helium significantly increased venous pressures and simultaneously decreased cardiac output. These changes were associated with decreases in organ blood flow due to increased peripheral resistance. Urinary output was reduced to a similar degree in the two groups. Blood gas analysis revealed pneumoperitoneum-induced metabolic acidosis in both groups, although hypercapnia was observed only in the carbon dioxide group. These findings suggest that pneumoperitoneum-related organ dysfunction may be due to increased intraperitoneal pressure rather than to hypercapnia.
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PMID:Hemodynamic and arterial blood gas changes during carbon dioxide and helium pneumoperitoneum in pigs. 855 28

The cardiopulmonary and metabolic changes experienced by patients undergoing laparoscopic cholecystectomy with CO2 pneumoperitoneum are not well understood. The purpose of this study is to determine changes of basal parameters during laparoscopy and evaluate their prognostic value. One hundred patients (26 obese, 39 older than 60 years, 7 obese and older than 60) undergoing laparoscopic cholecystectomy for uncomplicated cholecystolithiasis were included in the study. Arterial blood gases, respiratory and ventilatory parameters, heart rate, blood pressure were determined before the induction of pneumoperitoneum, at the peak of operation and after exsufflation. The obtained variables were statistically evaluated. Pneumoperitoneum caused significant hypercapnia and a decrease of pH accompanied with increase of expiratory CO2 concentration, which continued after exsufflation (p < 0.001). The changes were more expressed in older and obese patients and were solely of a respiratory type. No significant changes were observed in the heart rate, blood pressure, minute ventilation, PaO2, SaO2, base excess. Although changes were highly significant, there was no impact on clinical status--all patients survived without problems. The authors conclude that observed increase of carbon dioxide levels and decrease of pH had no impact on survival of patients. Changes were caused mostly by CO2 absorption from the abdominal cavity. Laparoscopic cholecystectomy is a safe and effective procedure even in older and obese patients, especially when insufflation is as low as possible.
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PMID:[Does insufflation of the abdomen in laparoscopic surgery affect acid-base and ventilatory parameters?]. 1059 68