Comparison of Hemodynamic Consequences of Hand Ventilation Versus Machine Ventilation for Transportation of Post?Operative Pediatric Cardiac Patients

Learning Objective: Hemodynamic monitoring during in?hospital transport of intubated patients is vital; however, no prospective randomized trials have evaluated the hemodynamic consequences of hand versus machine ventilation during transport among pediatric patients� post?cardiac surgery. The authors hypothesized that manual ventilation after pediatric cardiac surgery would alter hemodynamic and arterial blood gas (ABG) parameters during transport compared to mechanical ventilation. Design: A prospective randomized trial. Setting: Tertiary cardiac care hospital. Participants: Pediatric cardiac surgery patients. Materials and Methods: One hundred intubated pediatric patients were randomized to hand or machine ventilation immediately post?cardiac surgery during transport from the operating room to the pediatric post?operative intensive care unit (PICU). Hemodynamic variables, including end?tidal CO2 (ETCO2 ), oxygen saturation, heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), peak airway pressure (Ppeak), and mean airway pressure (Pmean), were measured at origin, during transport, and at the destination. ABG was measured before and upon arrival in the PICU, and adverse events were recorded. The Chi?square test and independent t?test were used for comparison of categorical and continuous parameters, respectively. Results and Discussion: The mean transport time was comparable between hand?ventilated (5.77 � 1.46 min) and machine?ventilated (5.96 � 1.19 min) groups (P = 0.47). ETCO2 consistently dropped during transport and after shifting in the hand?ventilated group, with significantly higher ETCO2 excursion than in machine?ventilated patients (P < 0.05). SBP and DBP significantly decreased during transport (at 5 and 6 min intervals) and after shifting in hand?ventilated patients than in the other group (P < 0.05). Additionally, after shifting, a significant increase in Ppeak (P < 0.001), Pmean (P < 0.001), and pH (P < 0.001), and a decrease in pCO2 (P = 0.0072) was observed in hand?ventilated patients than machine?ventilated patients. No adverse event was noted during either mode of ventilation. Conclusion: Hand ventilation leads to more significant variation in ABG and hemodynamic parameters than machine ventilation in pediatric patients during transport post?cardiac surgery. Therefore, using a mechanical ventilator is the preferred method for transporting post?operative pediatric cardiac patients

Cardiovascular and respiratory changes in children during diagnostic laparoscopy and laparoscopic surgery / 대한마취과학회지

BACKGROUND: Information concerning the cardiopulmonary effects of pneumoperitoneum in children is lacking. METHODS: Twenty eight patients were assigned to receive diagnostic laparoscopy (n = 12) or laparoscopic surgery (n = 16). Before insufflation of CO2, tidal volume was set at 10 ml/kg and respiratory rate was adjusted to achieve an end-tidal CO2 (P(ET)CO2) of 30-35 mmHg. Abdominal pressure was maintained at 10-15 mmHg by a CO2 insufflator. We measured the changes of systolic arterial pressure (SAP), heart rate (HR), P(ET)CO2 and peak airway pressure (PAP) at 5 min before (control value) and after CO2 insufflation and 5 min after CO2 deflation. RESULTS: SAP and PAP were increased significantly after pnemoperitoneum compared with the control both in diagnostic laparoscopy and laparoscopic surgery (P < 0.05). P(ET)CO2 was increased significantly after pneumoperitoneum and after CO2 deflation in laparoscopic surgery compared with the control and also with diagnostic laparoscopy (P < 0.05). Driving pressure (the difference between peak airway pressure and abdominal pressure) was increased significantly after pneumoperitoneum in laparoscopic surgery compared with diagnostic laparoscopy (P < 0.05). CONCLUSIONS: SAP, PAP and P(ET)CO2 increases during diagnostic laparoscopy and laparoscopic surgery, but this effect appears to be of smaller magnitude in diagnostic laparoscopy compared to laparoscopic surgery. We found that these changes had no clinically deleterious effects in healthy children.

Tracheal laceration detected by high end-tidal CO2 during endoscopic thyroidectomy / 대한마취과학회지

Endoscopic thyroidectomy is frequently used for cosmetic reasons, such as reducing cervical scarring. Subcutaneous gas insufflation with CO2 is needed to maintain the surgical space, and optimal surgical techniques and careful attention are required when conducting this procedure due to the limited space available for the endoscopic instruments. We report here a case of a tracheal laceration with a tear in the cuff of a reinforced tube, which was detected by an abrupt increase in end-tidal CO2 to 90 mmHg. Reintubation was achieved using a tube exchanger and the patient was effectively ventilated without complications.

Is CO2 Gas Insufflation in Endoscopic Thyroidectomy Safe or Not?: A Prospective Study through the Continuous Measurement of the End-tidal CO2 Pressure

PURPOSE: Endoscopic thyroidectomy has recently been widely used in clinical practice. The operative method can be classified into CO2gas insufflation and the gasless technique. This study assessed the safety of low pressure CO2gas insufflation (up to 6 mmHg) by performing continuous measurement of the end-tidal CO2 (ETCO2) pressure. METHODS: From March 2003 to October 2006, 95 patients (90 hemithyroidectomies and 5 total thyroidectomies) underwent endoscopic thyroidectomy. The low pressure CO2gas insufflation technique was applied in all cases. The ETCO2 pressure of the patients was measured by capnometry at the time of a pre-gas insufflation status (0 minutes) and at the time of post-CO2gas insufflation (30 minutes) and then it was measured every 30 minutes with also performing capnograms. We analyzed the ETCO2 pressure at the time of the pre-CO2gas insufflation status (0 min) and we compared this with that of each status by using paired T-test. RESULTS: For all 95 cases, the mean patient age was 36.2+/-9.1 (range: 21~57 years), the mean tumor size was 1.7+/-1.1 (range: 0.1~4.5 cm) and the mean operative time was 135.0+/-46.1 (range: 50~340 min). The mean ETCO2 pressure (mmHg) was 33.0+/-3.9 at the time of pre-CO2gas insufflation status (0 min); the mean ETCO2 pressure was 31.1+/-3.7 at 30 min (n=95), 33.5+/-3.7 at 60 min (n=95), 35.2+/-3.6 at 90 min (n=95), 34.9+/-3.7 at 120 min (n=90), 34.6+/-3.8 at 150 min (n=70), 34.1+/-3.4 at 180 min (n=40), 34.3+/-5.2 at 210 min (n=15) and 34.0+/-4.2 at 240 min (n=9). There was a significant difference the early post-CO2gas insufflation status (P0.05; at 60 min, 150 min, 180 min, 210 min, 240 min). At each time point, the ETCO2 pressures were all within the normal range. CONCLUSION: We successfully performed endoscopic thyroidectomy with using the low pressure CO2gas insufflation technique and there were no significant complications. We think that performing endoscopic thyroidectomy with using the low pressure CO2gas insufflation technique is a safe procedure.

Influence of Intra-Operative Regional Cerebral Blood Flow and the Carbon Dioxide Partial Pressure Difference between Arterial and End-Tidal on the Neurologic Outcome

OBJECTIVE: End-tidal partial pressure of carbon dioxide(PETCO2) is often used as an estimate of arterial partial pressure of carbon dioxide(PaCO2), with the understanding that PaCO2 usually exceeds PETCO2. During craniotomies, because hyperventilation is used to therapeutically lower intracranial pressure, the difference between arterial and end-tidal partial pressure of carbon dioxide(P(a-ET)CO2) has therapeutic implications. To determine how much information concerning neurosurgical operation and clinical outcome is provided by the PETCO2, PaCO2 and P(a-ET)CO2 during surgery, we evaluated 81 patients who had neurosurgical operation. METHODS: There were 51 males and 30 females with a mean age of 50.3 years(range 7-85 years). After the induction of general anesthesia, body temperature was maintained in a normothermia, endtidal CO2 was maintained 28-34mmHg and the systolic blood pressure was kept 90-120mmHg. ETCO2, PaCO2 and regional cortical blood flow(rCoBF) were checked at the time of dura closure. Neurologic outcome was evaluated at 8 hours after operation to rule out other factors which may influence on the patient's long-term outcome. Data were collected and compared by student's t-test or chi-square analysis. RESULTS: The PaCO2 was 34.6+/-5.2mmHg(range, 24.9-54.8), PETCO2 was 29.9+/-4.1mmHg(range, 20.0-45.0) and P(a-ET)CO2 was 4.7+/-3.5mmHg(range, -1.1-18.6). The correlation between the PaCO2 and PETCO2 was statistically significant(PETCO2=13.3-0.57xPaCO2). But there was no correlation of rCoBF with PaCO2 and ETCO2. P(a-ET)CO2 values less than 8mmHg were correlated well with good neurologic outcome compared with higher P(a-ET)CO2 patients. PaCO2, rCoBF, mean arterial blood pressure, arterial pH and initial Glasgow coma scale showed statistically significant correlation with neurologic outcome(p<0.05). CONCLUSION: Based on our study, P(a-ET)CO2 value could be used as a good prognostic factor during the neurosurgical operation and anesthesiologist should be tried to decrease this value. And in patients who has a intact brain autoregulation, rCoBF was not influenced by PaCO2 and ETCO2, entirely.

Early Recognition of Malignant Hyperthermia with Capnography: A case report / 대한마취과학회지

Malignant hyperthemia is an autosomal-dominant inherited disorder of the skeletal muscle cell charac terized by a hypermetabolic response to all commonly used inhalational anesthetics and depolarizing muscle relaxants. The clinical syndrome includes muscle rigidity, hypercapnia, tachycardia and myoglobinuria as result of increased carbon dioxide production, oxygen consumption and muscle membrane breakdown. Early recognition and vigorous treatment are very important factors to determine patient's prognosis in malignant hyperthermia. However, it is very difficult to diagnose malignant hyperthermia during anesthesia because malignant hyperthermia presents with multiple nonspecific signs and laboratory findings of variable intensity and time course during and after exposure to anesthetic agents. We report a case of malignant hyperthermia which was diagnosed early using capnography before the appearance of hyperthermia and successfully treated. The malignant hyperthermia episode developed 20 minutes after induction of anesthesia with thiopental sodium, pancuronium, isoflurane, N2O and O2. When we suspected episode, we could not observe any classical signs of malignant hyperthermia except unexplained tachycardia and elevated end-tidal CO2. We discuss here the usefulness of capnography in early recognition of malignant hyperthermia and the importance of early recognition in prognosis.

Effect of PaCO2, PETCO2, P(a-ET)CO2 and Regional Cortical Blood Flow on the Prognosis of Craniotomy Patients / 대한마취과학회지

BACKGROUND: Carbon dioxide is a potent cerebral vasodilator. The change of carbon dioxide partial pressure may influence the intracranial pressure and the patients' neurological outcome. There are few reports about the influence of end-tidal CO2 (ETCO2), arterial CO2 (PaCO2) and its pressure difference P(a-ET)CO2 during a craniotomy on the Glasgow coma scale (GCS) score for evaluation of neurological status. In this study, authors tried to discover the influence of PaCO2, PETCO2, and P(a-ET)CO2 on neurological outcome. METHODS: The data of PaCO2 and PETCO2 and P(a-ET)CO2 during a craniotomy was saved. The correlations between each parameter, the GCS score and rCoBF were analyzed. To prevent a direct effect on carbon dioxide tension, blood pressure and body temperature were maintained within a normal range. At the same time, we inserted a probe of the thermal diffusion flowmetry monitor in the subdural space to monitor the regional cortical cerebral blood flow (rCoBF). All the data was saved simultaneously, at the moment of dura closure. RESULTS: There was a fair correlation between the PaCO2 and PETCO2. A low PaCO2 level correlated well with a good GCS score but, not with PETCO2. The mean P(a-ET)CO2 value was 4.4 +/- 3.1 mmHg. The high P(a-ET)CO2 level correlated well with a poor GCS score. High rCoBF correlated well with a good GCS score. However, the changes of PaCO2 and PETCO2 showed no correlations with the rCoBF. CONCLUSIONS: As a result, if we decrease the PaCO2 level by hyperventilation and increase the rCoBF level through proper management during anesthesia, we can improve the patients' neurological outcome.

Anesthetic Management for Selective Dorsal Rhizotomy / 대한마취과학회지

Background: Cerebral palsy is due to static encephalopathy during perinatal period. Selective dorsal rhizotomy (SDR) involves selective division of posterior nerve roots to reduce spasticity and improve function in children with spastic cerebral palsy. Anesthesia during SDR must preserve muscle contraction in response to direct electrical stimulation of the dorsal nerve roots. We did this study to get the better management of anesthesia for SDR. Methods: Anesthetic records were reviewed for 16 patients who underwent SDR during January 1996 to August 1997. Demographic data; anesthetic drugs and doses; changes of vital signs and end tidal CO2; dorsal root stimulation; postoperative pain control were analysed. Results: The mean age of patients was 4.9+/-1.7 years old. The mean weight was 16.3+/-4.0 kg. The under 1 MAC concentration of isoflurane and 2~3 mcg/kg/hr fentanyl did not interfere with electrophysiologic monitoring. Esophageal temperature was increased significantly during electrical stimulation of dorsal roots. End tidal CO2 concentration had a tendency to increase after electrical stimulation too. Direct installation of 10~15 mcg/kg intrathecal morphine prior to dural closure, and postoperative 0.5 mcg/kg/hr fentanyl had a good postoperative analgesia without complication. Conclusions: Isoflurane and fentanyl during anesthesia, and intrathecal morphine with continuous infusion of fentany postoperatively are suggested a good anesthetic method for SDR.

End-tidal CO2 Measurement Via Nasal Cannula in Spinal Anesthesia / 대한마취과학회지

BACKGROUND: Major respiratory problems during spinal anesthesia occur due to several causes, particulary, high spinal block, use of sedatives or opioids, and underlying cardiopulmonary diseases. Pulse oximetry has prevented most of these problems, but has not provided rapid and accurate information of the patient's ventilation. We measured end-tidal CO2 tension via the side-stream capnometer with a small rubber cannula and investigated its effectiveness in ventilatory monitoring under spinal anesthesia. METHODS: Nineteen patients were involved in this study. We performed spinal anesthesia with 0.5% heavy marcaine 12 mg (L3-4 interspace). After fixation of spinal sensory blockade level, 0.035 mg/kg of midazolam was administered intravenously to sedate the patient. A polyvinylchloride catheter with a rubber extending nasal cannula was used for sampling of respiratory gas. PETCO2 was measured at 15 minutes after spinal anesthetic injection (before sedation), and at 5 minutes after midazolam injection (after sadation). Arterial CO2 tension was also measured during PETCO2 measurement. RESULTS: There was no correlation of spinal maximal sensory blockade level with repiratory rate, PaCO2 and PETCO2. Linear regression analysis of arterial vs. end-tidal CO2 yielded a slope of 0.92, r=0.81 and p<0.001 (before sedation), and a slope of 0.98, r=0.79 and p<0.01 (after sedation). Arterial to end-tidal differences were 4.2+/-2.8 mmHg (before sedation) and 4.3+/-3.0 (after sedation), but there was no significant difference in comparing them with each other. Conclusions : We conclude that this form of PETCO2 measurement is useful in continuous, noninvasive monitoring of ventilation in patients under spinal anesthesia.

Hyperthermia during General Anesthesia: A case report / 대한마취과학회지

The fulminant malignant hyperthermia (MH) is now encountered less frequently because of increased awareness of the condition by anesthesiologist and better use of mornitoring facilities. Thus there is also an increase in the number of aborted cases, in which anesthesia is stopped and treatment instituted as soon as MH is thought to be likely. We presented a case of an abortive MH in 18 years old male patient during the discectomy on the third and fourth lumbar intervertebral spaces. Anesthesia was induced with thiopental sodium and succinylcholine and then maintained with nitrous oxide, oxygen and enflurane. After induction, there were persistent tachycardia, elavation of end-tidal CO2 tension on capnography, spontaneous tachypnea, body temperature elevation up to 38.2oC, respiratory acidosis and highly level of CPK, myoglobulin in serum and urine. Under the suspicion of MH, all anesthetics were discontinued and vigorous emergency treatment was attempted including ventilation with high flow of 100% oxygen (8 l/min), changing all anesthetic circuits, and cooling measurements such as chilled intravenous solution infusion, gastric lavage with cold saline, alcohol and ice water pack over the body. Fourtunately, he recovered well and discharged without complications.

The Effect of Decrease in Cardiac Output on End-Tidal CO2 and Difference between Arterial and End-Tidal CO2 Tension / 대한마취과학회지

Capnogram, monitoring of end-tidal CO2, has been a popular tool for assessment of ventilatory status during modern anesthesia. A normal curve on capnogram suggests normal CO2 production, adequate circulation, and adequate ventilation. Level of end-tidal CO2. is different from that of arterial CO2 even in normal individual. The difference is originated from alveolar dead space gas which dilute concentration of CO2 from normal alveoli. In clinical situation, the major factor which determines alveolar dead space is low pulmonary blood flow. Decrease of alveolar capillary perfusion from low cardiac output is the most important cause of low measure of end-tidal CO and large difference between arterial CO2 and end-tidal CO2 concentration in perioperative period. To understand the effect of cardiac output on end-tidal CO2 tension and the difference between arterial CO2 tension and end-tidal CO2 tension, We measured cardiac output before and dutiag administration of nitroglycerine and sodium nitropruside for relieve of myocardial load before aortic clamping in 30 male patients undergoing aortic recontructive surgery under endotracheal anesthesia for repair of infrarenal aortic obstruction. We also measured arterial CO2 tension, and end-tidal CO2 tension at the time of 10% decrease(phasel), 15% decrease(phase2)and 20% decrease(phase3) of cardiac output respectively. Measured values were statistically analyzed to evaluate correlation between cardiac output and end-tidal CO2 tension. The results are as follows: 1) Decreases of cardiac output brought about significant decrease in end-tidal CO2 in all phases compared to control value(p<0,05). 2) Decreases of cardiac output brought about significant increase in the difference between arterial- end-tidal CO2. tension in all phases compared to control value(p<0.05). 3) Changes in cardiac ourput correlated with changes in end-tidal CO2 tension significantly(p=0.0001, r=0.61, slope=2.01). 4) Changes in cardiac ourput correlated with changes in differences between arterial-end-tidal CO2 tension significantly(p=0.0001, r=-0.59, slope=-1.63). In conclusion we suggest that measurement of end-tidal CO2 tension, especially difference between arterial and end-tidal CO2 tension, may be a useful indicator for detection of cardiac output change during operation.

Influence of sodium nitroprusside-induced hypotension on the difference between arterial and end-tidal CO_2 tension in dogs / 中华麻醉学杂志

0.05) in both groups. In group B,cardiac output decreased by 13% at 15th min following deliberated hypotension (P0.05). It is suggested that PaCO_2 can be evaluated continuously and noninvasively by monitoring end-tidal CO_2 tension during SNP-induced hypotension.

Influence of controlled hypotension Induced by PGE_1 on the difference of arterial and endtidal CO_2 tension in dogs / 中华麻醉学杂志

0. 05),cardiac index decreased from 12. 5% to 13. 3 % during hypotension (P 0. 05 ). It was concluded that PaCO2 can still be followed continuously and noninvasively by monitoring end-tidal CO2 tension during hypotension induced by PGE,

Changes in End Tidal CO2 before and After Release of Tourniquet / 대한마취과학회지

In 24 healthy adult patients having orthopedic surgical procedures requiring the use of a tourniquet under general anesthesia with controlled mechanieal ventilation, we have deter- mined ehanges in end tidal CO2(PetCO2) and arterial blood gas values before and after release of tourniquet. After deflation of tourniguet, PETCO and PaCO2 increased significantly with the maximal elevation occuring within two minutes. The pH level decreased significantly and maximally within three minutes. There was statistically significant linear correlation between PCO and PaCO2 Sugesting prediction of the PaCO2, level by monitoring the PetCO2 level. On these findings, hyperventilation may be indicated to facilitate the return of PaCO2 and pH to baseline just before and for several minutes after tourniquet release, especially in patients with increased intracranial pressure. In conclusion, we recommend noninvasive monitoring of the PetCO2 level instead of invasive measure-ment of the PaCO2 level.

Clinical Study of the Changes in Arterial Blood Gas and End Tidal CO2 after Release of Tourniquet / 대한마취과학회지

The tourniquet is not only used for facilitation of microaurgery by the bloodless surgical field on the extremities but prepared for the intravenous regional anesthesia and isolation arm test estimated the degree of the neuromuscular transmission in the anesthetic field. On the contrary, there are various complications, such as nerve paralysis and tissue damage from compression, and metabolic and hemodynamic changes from ischemia after application of the tourniquet. Since a sudden increase in PaCO2 immediately following tourniquet deflation is one of the important factors in the hemodynamic changes, we have observed the ehanges of PaCO2 and PCO2, after release of the tourniquet on the upper and the lower extremity under the general anesthesia with enflurane, N2O and respiratory control maintaining PaCO2 level (35 mmHg). The results obtained were as follows; PETCO2, PaCO2 and HCO2- were significantly elevated to peak level within 1 minutue after tourniquet release on the upper and the lawer extremity, except HCO2 on the upper extremity, and there were more severe changes on the lower extremity. pH and base excess were reduced to significantly lowest level 1 minutue and 5 minutes after tourniquet release respectively, and their changes were more reduction on the lower extremity. There were no statistically significant variations in PaO2 on the extremities. In the relationship between tourniquet time and P, it was statistically significant linear on the lower extremity (p<0.05) only. Conlusively, since the sudden changes of PaCO2, pH and base excess after release of tourniquet are closely related with PaCO2, on time and degree, noninvasive monitoring of PaCO2 has rapid interpre- tation to change in PaCO2 after release of tourniquet.

Relationship between Arterial and End-tidal CO2 Tensions in Anesthetized Infants and Children / 대한마취과학회지

End-tidal (PETCO2) and arterial CO2, tensions (PaCO2) were measured in 66 anesthetized infants and children. 35 patients were under 7 year-old (group 1) and 31 patients were over 7 year-old (group 2). In both groups, differences between PETCO2, and PaCO2, were evaluated, and correlations between PETCO2, and PaCO2, were carried out. The children in group 1 had a PaCO2, (mean+/-S.D.) of 29.2+/-4.1mmHg and a PCO2, (mean+/-S,D.) of 29.2+4.1mmHg. The range of the PaCO2, and PETCO2 difference (P alpha-ETCO2) was from -1.0 to 1.2 mmHg. The children in group 2 had a PaCO2 (mean+/-S.D.) of 29.3+/-3.0 mmHg and a PETCO2 (mean+/-S.D.) of 29.3+/-4.0mmHg. The range of the P alpha-ETCO2 was from 1.9 to 2.5mmHg. The significant direct correlations between PaCO2 and PETCO2 in both groups (r=0.96,0.84, respec-tively) were defined. The difference between groups wasnt statistically significant. It is concluded that in normal infants and children during anesthesia, noninvasive measurement of PET CO2 can be used as a reliable estimate of PaCO2 and that PETCO2did not differ significantly from PaCO2.

A Study on the Middle Ear Pressure Variation during General Anesthesia / 대한마취과학회지

This study was carried out to observe and evaluate the middle ear pressure(MEP) change by nitrous oxide(N2O) and end tidal PCO2 during general anesthesia with halothane or enflurane. MEP was measured during general anesthesia by impedance audiometer(GSI 28 Auto tymp model) in 50 patients who were relatively healthy without upper respiratory tract infection and otologic problems from August 1987 at Chonbuk National University Hospital. The results were as follows: 1) During general anesthesia with 100% O2 and halothane or enflurane, MEP was decreased progressively under the preinduction level with time. 2) The decrease in MEP during general anesthesia with 100% O2 and halothane or enflurane was reversed by relative hypoventilation, but MEP showed negative values in all patients. 3) End tidal PCO2 was increased progressively by relative hypoventilation and returned gradually to pre-hypoventilation level by normoventilation. 4) MEP was increased during general anesthesia using N2O, which is propotional to the concentration of N2O by 20 minutes. Thereafter, MEP remained increased until termination of N2O administration. From the above results, it is concluded that MEP is increased during anesthesia using N2O. MEP can also be affected by end tidal PCO2 even though physiologic range. Therefore, it is prudent to avoid N2O especially when hyperventilation is not adequately permitted during general anesthesia for middle ear surgery and patient with middle ear disease.