The Effect of Soundproof Headphones During Orthopedic Surgery Under Spinal Anesthesia on Patients' Physiological Indices and Duration of Recovery: A Randomized, Controlled, Clinical Trial.

PURPOSE: With spinal anesthesia, the patient remains awake and may hear different noises when undergoing orthopedic surgery, and these noises may lead to some discomfort. The aim of this study was to investigate the effect of wearing soundproof headphones during orthopedic surgery under spinal anesthesia on the patients' physiological indices and duration of recovery. DESIGN: This was a randomized clinical trial with a control group. METHODS: The sample included 184 patients selected through convenience sampling, who were then randomly allocated to the control and intervention groups. Data were collected by observation and by filling out a researcher-made checklist. Soundproof headphones were placed on the patients' ears during surgery in the intervention group, while the patients in the control group underwent surgery with no headphones. Physiological indices were measured at five time points, and the patients' length of stay in the postanesthesia care unit (PACU) was also measured. FINDINGS: The mean changes in systolic and diastolic blood pressure were significantly lower in the intervention group (P < .02 and P < .005) at two of the time points. The mean changes in heart rate were also significantly lower in the intervention group (P < .003, P < .01) at four time points. The respiratory rate and oxygen saturation were both significantly higher in the intervention group (P < .001, P < .03, P < .002, P < .008) at four time points. The two groups also had significant differences (P = .004) in terms of the length of stay in the PACU, which was shorter in the intervention group. CONCLUSIONS: Reducing the exposure to noise via soundproof headphones may improve patients' physiological indices in noisy orthopedic surgeries, and may also decrease their length of stay in the PACU. This method is recommended as an easy and applicable way to ameliorate the patients' experiences of this surgery.

Comparison of Success Rate and Safety of Nasotracheal Intubation by Conventional and Finger-Guided Method in Patients Undergoing Maxillofacial Surgery.

Background: Different techniques have been introduced to reduce the complications of nasotracheal intubation. The aim of this study was to compare the incidence of nasotracheal intubation complications in finger-guided and conventional methods. Materials and Methods: In this double-blind randomized trial study, 70 patients who were candidates for oral and maxillofacial surgery who required nasal intubation were included in the study finally of which 33 patients with conventional method and 35 patients with finger-guided tubes in the nasopharynx were analyzed at the end of the study. Variables such as success rate, hemodynamic response, and complications of intubation were compared between the two groups. Results: There was no significant difference between the two groups in terms of hemodynamic response to intubation (P > 0.05). There was a significant difference between the two groups in terms of success in tracheal intubation (P < 0.05). There was a significant difference between the two groups in terms of epistaxis immediately after intubation (P < 0.05). There was no significant difference between the two groups in terms of nasal turbine fractures (P > 0.05). However, the frequency of submucosal intubation in the conventional method was significantly higher than the other group (P = 0.02). Conclusion: Nasotracheal intubation using the finger guiding technique in the nasopharynx is associated with a higher success rate and less complications after intubation such as epistaxis and submucosal intubation compared to the conventional method.

The Predicting Ability of Serum Phosphorus to Assess the Duration of Mechanical Ventilation in Critically Ill Patients.

BACKGROUND: No previous study exists to evaluate serum phosphorus (Ph) level as a predictor of the need to mechanical ventilation (MV). This study was designed to determine the predictive ability of admission serum Ph level on MV in patients admitted in Intensive Care Unit (ICU). MATERIALS AND METHODS: This prospective study was conducted on 100 patients (>16 years old), admitted to our ICU over 1-year. Patients were classified into two groups according to the days of the need to MV. Group A: Patients who required equal or <5 days MV, and Group B: Patients who required more than 5 days of MV. We measured total serum Ph concentrations at the times of ICU admission, connecting to the ventilator and weaning from the ventilator. RESULTS: There were significant differences between serum Ph concentration on admission to ICU (Group A: 3.39 ± 0.39 mg/dl, Group B: 2.89 ± 0.31 mg/dl, P < 0.001), at the time of connecting to ventilator (Group A: 2.49 ± 0.38 mg/dl, Group B: 2.25 ± 0.26 mg/dl, P = 0.004) and weaning from ventilator (Group A: 3.42 ± 0.33 mg/dl, Group B: 2.98 ± 0.34 mg/dl, P < 0.001) between two groups. Duration of ICU stay in Group A was 6.08 ± 1.48 days and in Group B was 15.35 ± 6.45, this difference was significant (P < 0.001). We found the best cut-off point of 3.07 for serum Ph concentration to predict the longer duration of MV. CONCLUSION: According to the results of our study, hypophosphatemia may increase the need to MV. Therefore, monitoring serum Ph level is a good prognostic factor to predict the need to ventilation.

The effect of oral tizanidine on postoperative pain relief after elective laparoscopic cholecystectomy.

BACKGROUND: Cholecystectomy is considered as the most important and relatively common postoperative pain control often begins in recovery room by using systemic narcotics that may have some side effects. The aim of this study is to evaluate the effect of premedication with oral tizanidine on pain relief after elective laparoscopic cholecystectomy. MATERIALS AND METHODS: In this double-blinded clinical trial, 70 adults of American Society of Anesthesiologist physiologic state 1 and 2 scheduled for elective laparoscopic cholecystectomy under general anesthesia were studied and randomly divided in two study and control groups. Ninety minutes before the induction of anesthesia, patients received either 4 mg tizanidine (study group) orally in 50cc or the same volume of plain water as a placebo (control group). Then, the vital signs, pain intensity, duration of stay in recovery, and the analgesic consumption were measured and then compared in both groups during 24 h postoperatively. RESULTS: There was no significant difference in patient characteristics, with respect to age, weight, gender, and duration of anesthesia and surgery between the groups (P > 0.05). The pain intensity, need for analgesic drugs (34.57 ± 8.88 mg vs. 101.86 ± 5.08 mg), and the duration of stay in recovery room (67.43 ± 1.59 min vs. 79.57 ± 5.48 min) were significantly lower in tizanidine group than that of the control group. CONCLUSION: Oral administration of 4 mg tizanidine before laparoscopic cholecystectomy reduces postoperative pain, opioid consumption, and consequence of the duration of stay in recovery room without any complication.

A randomized controlled trial comparing the effect of intravenous, subcutaneous, and intranasal fentanyl for pain management in patients undergoing cesarean section.

BACKGROUND: The objective of this study was to evaluate and compare the effects of three methods of using intravenous (IV), subcutaneous and intranasal (IN) fentanyl for pain management following general anesthesia in patients undergoing cesarean section. MATERIALS AND METHODS: A prospective, randomized, single-blind clinical trial was done on 75 patients aged 20-40 years, American Society of Anesthesiology-1, who had a normal singleton pregnancy beyond 36 weeks of gestational age. Patients were randomized to receive 50 µg fentanyl intravenously (Group 1), subcutaneously (Group 2) or intranasally (Group 3) after closure of incision. The pain intensity, nausea, the systolic, and diastolic blood pressures were assessed. RESULTS: All groups were equivalent for baseline characteristics. The average pain visual analog scale (VAS) score was less in the second group who received fentanyl subcutaneously at the time of recovery admission (6.8 ± 1.5) (P = 0.037) and after 3 h (6.36 ± 1.5) (P = 0.033) postoperatively. The mean VAS score of nausea and the mean systolic and diastolic blood pressures were not significantly different between three groups throughout the study (P > 0.05). CONCLUSION: subcutaneous fentanyl is an effective alternative to IV and IN route of administration for pain management.

Comparison of the effects of colloid preload, vasopressor administration and leg compression on hemodynamic changes during spinal anesthesia for lumbar disc surgery in knee-chest position.

BACKGROUND: Hypotension is a serious and the most common adverse effect of spinal anesthesia. Many studies have focused on prevention of hypotension due to spinal anesthesia. The aim of this study was to compare the efficacy of three different methods of using colloid, ephedrine and wrapping of extremities on the incidence of hypotension and bradycardia following spinal anesthesia in patients undergoing elective lumbar disc surgery in knee-chest position. MATERIALS AND METHODS: A total of 180, ASA (I-II), adult patients candidate of lumbar disc surgery in one or two levels who met the inclusion criteria were randomly allocated in one of three treatment groups of receiving Voluven (6% hydroxyethyl starch 130/0.4 in 0.9% sodium chloride injection), ephedrine and leg wrapping. After establishment of spinal anesthesia, patients were outsourced and knee-chest position was done. Heart rate and blood pressure of patients were recorded at different times till 60 min after spinal injection. Statistical analyses of data were performed with SPSS (version 20) and by considering groups, values of P < 0.05 were considered statistically significant. RESULTS: Mean systolic blood pressure (119.5 ± 7.4 mmHg) and mean heart rate (71.7 ± 6.7 b/min) were higher in a group receiving Voluven (P < 0.05). The Voluven group significantly experienced less nausea and vomiting in recovery room in comparing with other groups (P = 0.027). They also received significantly less ephedrine (P = 0.012) and ondansetron [12 (20%)] (P = 0.02). Furthermore, patients receiving elastic bandage had significantly more blood loss than the other groups (P = 0.013). CONCLUSION: Colloid therapy was the most effective method in keeping hemodynamic stability, prevention of decrease in systolic blood pressure and incidence of side effects during spinal anesthesia for lumbar disc surgery in knee-chest position.

The predicting ability of serum potassium to assess the duration of mechanical ventilation in critically ill patients.

BACKGROUND: No previous study has been done to evaluate the admission serum potassium level as a predictor of morbidity or need for mechanical ventilation. The aim of this study is to determine the predictive ability of serum potassium on admission, in critically ill trauma patients, and to evaluate the relation of the potassium level to organ failure, length of stay, ventilator need, and duration of mechanical ventilation. MATERIALS AND METHODS: A prospective, observational study was done on 100 patients >16 years old, admitted to the Medical-Surgical Intensive Care Units (ICU), for over one year. Patients were classified into Group A: Patients who required equal or less than five days of mechanical ventilation and Group B: Patients who required more than five days of mechanical ventilation. The total serum potassium concentrations were measured and the Sequential Organ Failure Assessment (SOFA) score was recorded at the time of admission to the ICU, when connected to the ventilator, and then at the time of weaning from the ventilator. RESULTS: There was no significant difference between the Serum K concentrations between the two groups, on admission. However, there were significant difference between the Serum K concentrations at times of receiving and weaning from mechanical ventilation (MV) between the two groups. We found the best cut-off point of 3.45 for serum potassium concentration, to predict the need for longer duration of MV. CONCLUSION: Development of hypokalemia during an ICU stay is associated with the need for mechanical ventilation. Monitoring of the serum potassium levels may be a good prognostic factor for the requirement of mechanical ventilation.

The effect of early ambulation on the incidence of neurological complication after spinal anesthesia with lidocaine.

BACKGROUND: Transient neurological symptoms (TNS), was described in patients recovering from spinal anesthesia with lidocaine but its etiology remains unknown this study was evaluated the influence of ambulation time on the occurrence of TNSs after spinal anesthesia with lidocaine 5%. MATERIALS AND METHODS: This randomized clinical trial was conducted on 60 patients with American Society of Anesthesiologists Grades I and II, who were candidates for lower abdominal surgery in supine or lithotomy positions. Patients were randomly divided into early ambulation group (Group A) who were asked to start walking as soon as the anesthesia was diminished or to the late ambulation group (Group B) who walked after at least 12 h bedridden. Participants were contacted 2 days after spinal anesthesia to assess any type of pain at surgical or anesthesia injection site, muscle weakness, fatigue, vertigo, nausea, vomiting, headache, and difficult urination or defecation. RESULTS: Four subjects (13.3%) in Group A and two patients (6.7%) in Group B had pain at anesthesia injection site (P = 0.019). Fourteen patients in Group A (46.7%) and six patients in Group B (20%) had post-dural puncture headache (P = 0.014). Participants in Group B reported difficult urination more than Group A (P = 0.002). there were not statistically significant differences between two groups regarding frequency of fatigue, muscle weakness, vertigo, nausea, vomiting, difficult defecation, paresthesia, and the mean of visual analogue scale at the surgical site. CONCLUSION: Early ambulation after spinal anesthesia with lidocaine did not increase the risk of neurologic complication.

Effect of nebulized budesonide in preventing postextubation complications in critically patients: A prospective, randomized, double-blind, placebo-controlled study.

BACKGROUND: The efficacy of steroid administration in the prevention of postextubation complications in critical care remains controversial. The purpose of this study was to determine whether administration of nebulized budesonide in critically ill patients reduces the occurrence of postextubation airway complications. MATERIALS AND METHODS: This was a prospective, randomized, double-blind, placebo-controlled study. We prospectively followed up 70 adult patients in the intensive care unit who were intubated for more than 48 h. Patients received either nebulized budesonide (1 mg every 12 h; n = 35) or placebo (normal saline; n = 35) until 48 h after extubation. Then, the postextubation complications were assessed and recorded within 48 h of extubation. RESULTS: The incidence of respiratory distress was lower in budesonide group (8.6% vs. 31.4%, P = 0.017). Reintubation with mechanical support was necessary in 8.6% (3.35) of patients in the budesonide group and 31.4% (11.35) of patients in the placebo group (P = 0.017). CONCLUSION: Nebulized budesonide after extubation is effective in reducing the incidence of reintubation and respiratory distress in adult patients.

Evaluation of in vivo effects of Oxytocin on coagulation of parturient during cesarean delivery by thromboelastography.

OBJECTIVE: Oxytocin routinely used as an uterotonic drug in cesarean delivery. Clothing problems, adverse effects on fibrinogen and bleeding were presented as side effects of oxytocin. In in vivo investigation, modest hypercoagulable state was suggested as a side effect for infusion of oxytocin in parturients. In this study, effects of two different infusion rates of oxytocin on coagulation of parturient were evaluated during cesarean delivery. METHODS: In a randomized double-blinded clinical trial, 84 healthy parturient in two equal groups took oxytocin infusion with the rate of 15 IU/h (Group A) or 30 IU/h (Group B), after the umbilical cord clamping. Coagulation status measured 30 min after beginning of infusion by thromboelastography. Data were analyzed by χ(2), paired sample test and ANOVA considering as significant at P < 0.05. FINDINGS: The mean (standard deviation) of variables in Groups A and B were 2.4024 (0.86) and 2.0429 (0.68) for K (kinetics of clot development), 55.4429 (11.30) and 60.7595 (10.41) for α (speed of clot strengthening) and 59.779 (19.15) and 70.61 (11.30) for maximum amplitude (maximum clot strength), respectively. The P values for these variables were 0.036, 0.028 and <0.001, respectively; these changes are consistent with increasing coagulability. Other measures did not have significant differences. CONCLUSION: This in vivo investigation clarified that increasing infusion rate of oxytocin to 30 IU/h can augment coagulability in term parturients.

Preemptive subcutaneous tramadol for post-operative pain in lower abdomen surgeries: A randomized double blinded placebo-control study.

BACKGROUND: Recently, the preemptive analgesic effects of subcutaneous infiltration of tramadol (T) in the site of incision have not been extensively studied. In this study, we investigated the effect of subcutaneous T infiltration before the incision of surgery on post-operative pain, in lower abdomen surgeries. MATERIALS AND METHODS: This double-blind study was carried out on 90 patients (18-65 years) of American Society Anesthesiologists physical status I and II who were candidates for a lower abdomen surgery during 2011. They were randomly assigned to receive preemptive subcutaneous T or normal saline (NS). The visual analogue scale for pain (VAS) in rest and cough position and opium total dose consumption were compared between two groups in times 0, 15, 30, 60 min and 2, 4, 6, 12, 24 h after the surgery. RESULTS: The VAS in cough and rest position in the first 24 h following the surgery was lower in group T (P < 0.05). Opium consumption was lower in group T (P < 0.05). CONCLUSION: Subcutaneous preemptive infiltration of T before surgical incision reduces post-operative opioid consumption.

Hypercapnic hyperventilation shortens emergence time from Propofol and Isoflurane anesthesia.

OBJECTIVE: The aim of this study is to compare the effects of hypercapnic hyperventilation and normocapnic normoventilation on emergence time from propofol and isoflurane anesthesia. METHODS: In this clinical trial, the differences in emergence time were evaluated in 80 patients undergoing elective abdominal surgery in Alzahra University hospital, Isfahan, Iran, in 2011-2012. Patients were randomly divided into four groups (groups 1-4) receiving isoflurane hypercapnic hyperventilation, isoflurane normocapnic normoventilation, propofol hypercapnic hyperventilation, and propofol normocapnic normoventilation, respectively. Hypercapnia was maintained by adding CO2 to the patient's inspired gas during hyperventilation. The emergence time and the duration of stay in recovery room in the four groups were measured and compared by one-way analysis of variance (ANOVA) and least significant difference tests. FINDINGS: The average emergence time in groups 1, 2, 3, and 4 were (11.3 ± 3.2), (15.2 ± 3.8), (9 ± 4.2) and (11.8 ± 5.3) min, respectively. These differences were significant (P = 0.001). In patients receiving propofol hypercapnic hyperventilation, the emergence time was faster than in other groups. There was also a significant difference in duration of stay in recovery room between the groups (P = 0.004). Patients who received isoflurane hypercapnic hyperventilation had a shortest length of stay in the recovery room. CONCLUSION: The emergence time after intravenous anesthesia with propofol can be shortened significantly by using hyperventilation and hypercapnia, without any side effects.

Comparing the preventive effect of midazolam and midazolam-dexamethasone on postoperative nausea and vomiting in elective middle ear surgery.

BACKGROUND: Nausea and vomiting are common postoperative complications with incidence of 20-80% depends on the surgery type, anesthetic drugs, age, sex, etc. This complication may lead to patient discomfort, intraocular, and intracerebral pressures increase, sutures rupture, esophageal injury, and rarely death. Many studies reported that midazolam and dexamethasone alone can decrease postoperative nausea and vomiting (PONV), but their combination has never been studied yet. The aim of this study was to compare the effect of midazolam and midazolam-dexamethasone on PONV after middle ear surgery. MATERIALS AND METHODS: 66 ASA I and II patients aged 15-65 year scheduled for elective middle ear surgery under general anesthesia randomly divided into two groups. Immediately after induction of the anesthesia group one (M) received midazolam 0.075 mg/kg and group two (M+D) received combination of midazolam (0.075 mg/kg) plus dexamethasone (0.05 mg/kg). Then the severity of nausea was measured by visual analog scales 0-10 (VAS) in recovery room at 6, 12, and 24 h after surgery. Metoclopramid (0.1 mg/kg) was administrated I.V. slowly if nausea score was above 3 or patient had vomiting. The postoperative need for antiemetics and the duration of stay in recovery room were recorded. Values of P<0.05 were considered statistically significant. RESULTS: There were no significant differences in age, gender, and weight between the two groups. There was no significant difference in the mean nausea scores between two groups except after 12 h postoperatively (1.39 ± 3.19 in M group vs. 0.42 ± 1.71 in M+D group). The mean vomiting frequency was significantly less in midazolam-dexamethasone group in the recovery room (0.9 ± 0.29 vs. 0 ± 0) and at 6-12 h (1.09 ± 2.41 vs. 0.3 ± 0.8), and 12-24 h (0.42 ± 1.32 vs. 0.03 ± 0.17) postoperatively. During the first 24 h postoperatively, the metoclopramid consumption was significantly less in combination therapy (6.48 ± 9.54) than in the midazolam group (12.9 ± 23.44) (Value<0.5). CONCLUSION: The combination of midazolam-dexametazone is more effective than midazolam alone in prevention of postoperative vomiting after middle ear surgery. Therefore, we recommend combination therapy for patients who are prone to PONV.

Analgesic effects of ketamine infusion on postoperative pain after fusion and instrumentation of the lumbar spine: a prospective randomized clinical trial.

BACKGROUND: Intractable pain occurs as a result of extensive damage to soft tissue, bones and muscles after fusion of lumbar spondylolisthesis. Although different drugs and protocols have been suggested for postoperative pain management, the best method of treatment has not been proposed yet. Therefore, this study tried to compare the efficacy of ketamine infusion and routine opioid administration on postoperative pain. METHODS: A double-blind prospective randomized clinical trial was performed on 45 patients candidate for fusion of lumbar spondylolisthesis. Patients were divided into two groups of A (treatment) and B (control). In group A, pain was controlled by intravenous infusion of ketamine. Morphine was also administrated when the patients scored their pain above 4 on a visual analogue scale (VAS). In group B, intravenous infusions of morphine were performed every 6 hours. VAS and whole dosage of morphine were compared between two groups every 6 hours. RESULTS: Morphine and ketamine were both effective on pain control. Mean values of pain intensity at the first to fourth time points were 2.1, 1.8, 1.6, and 1.7 in group A and 3.9, 3.4, 3.5, and 3.5 in group B, respectively (p < 0.01 for all periods). However, ketamine was more efficient in pain reduction during the first 24 hours (p < 0.001). CONCLUSION: Ketamine could be a good alternative analgesic after fusion of lumbar spondylolisthesis. However, the probable side effects should also be considered. Ketamine infusion is more effective than morphine on postoperative pain control. In addition, tolerance to drug application is not a challenging problem at least during 24 hours after operation.

Comparative study of two anesthesia methods according to postoperative complications and one month mortality rate in the candidates of hip surgery.

BACKGROUND: Surgery for hip fractures can be done under general or neuraxial anesthesia. This study aimed to compare these two methods concerning their postoperative complications, duration of operation, hospitalization and the mortality rate within a period of one month after surgery. METHODS: 400 patients aged more than 30 years old and scheduled for elective operative fixation of fractured hip, randomly enrolled in two equal groups of general (GA) and neuraxial (NA) anesthesia. Hemoglobin level was measured before and 6 hours, 2, 3 and 5 days after the surgery. The intra and postoperative blood loss, duration of surgery, the severity of pain at the time of discharge from recovery and at the 2(nd), 3(rd) and 5(th) postoperative days were recorded. Statistical analysis was performed using SPSS version 12.0 by Mann-Whitney, chi-square, and t tests. P < 0.05 was considered significant. RESULTS: Both groups were similar regarding age, weight, and gender ratio. There was no significant difference in baseline hemoglobin, duration of surgery, length of hospitalization before surgery and the type of surgery. The mean of intraoperative blood loss and visual analogue score (VAS) in recovery and at the 3(rd) postoperative day, and also the length of hospitalization after surgery were significantly less in neuraxial anesthesia group. Both groups showed a significant decrease in hemoglobin values on the 2(nd) and 3(rd) postoperative days comparing to the baseline (p < 0.001). CONCLUSIONS: The morbidity and mortality rates of patients undergoing hip surgery were similar in both methods of anesthesia, but postoperative pain, blood loss, and duration of hospitalization were more in patients undergoing general anesthesia.

Comparative evaluation of different values of bispectral index in determination of the appropriate level of anesthesia for tracheal intubation during inhalational induction of anesthesia in pediatrics.

BACKGROUND: Induction of anesthesia is the most crucial period of general anesthesia. Inhalational induction is the most commonly used technique in pediatric anesthesia. Tracheal intubation can be done after reaching the deep levels of anesthesia. The depth of anesthesia is often difficult to be judged. Bispectral index is a measure of the effects of anesthesia on brain. This study was designed to evaluate the efficacy of bispectral index (BIS) in clarifying suitable depth of anesthesia for tracheal intubation during inhalational induction of anesthesia. METHODS: In a clinical trial, ninety patients, ASA I & II, 1 to 6 years old, scheduled for elective surgery were enrolled into the study. After starting BIS monitoring, patients randomly were divided into three groups. Then, anesthesia was induced by gradual increase of halothane in 50% mixture of oxygen (O(2)) and N(2)O and continued until target BIS (60 ± 2, 50 ± 2 and 40 ± 2) achieved. After tracheal intubation, the duration of laryngoscopy and the presence of laryngospasm, bronchospasm, laryngoscopy failure, the movement of extremities and the changes in SpO2 and BIS were recorded. The data were analyzed by chi-square and ANOVA at 0.05 level of significance. RESULTS: BIS could not determine the appropriate level of anesthesia for tracheal intubation in this setting. There were no differences in laryngoscopy duration and the occurrence of laryngospasm, bronchospasm, laryngoscopy failure, extremity movement and awakening time among three groups. CONCLUSIONS: These results confirmed that there was no significant difference in the incidence of complications related to intubation at different BIS values (from 60 to 40) during inhalation induction, and probably to achieve an adequate or more reliable depth of anesthesia, the lower values of BIS is required.

Bispectral index response to cricoid pressure during induction of general anesthesia.

BACKGROUND: Because the effects of cricoid pressure (CP) on BIS values have not been evaluated, this prospective study was designed to assess the BIS values after application of CP in adult patients during the routine induction of general anesthesia. METHODS: We randomly allocated 70 patients (ASA-I) aged 18-64 years, listed for elective surgery into two groups of cricoid (CP) and non-cricoid (nCP). In the cricoid group, bimanual cricoid pressure was performed after the induction of anesthesia and in the nCP group, simple placement of hands without exerting pressure was performed. Arterial blood pressure, heart rate and BIS were measured and recorded immediately before and after application of cricoid pressure, before laryngoscopy and intubation and then every one minute after intubation until 4 minutes. The data were compared between and within groups using the mixed-design analysis of variance. RESULTS: One minute after application of cricoid pressure and before laryngoscopy, BIS showed significantly higher value compared with the nCP group. Furthermore, one min after intubation, BIS values and arterial blood pressure in-creased significantly in both groups compared with the baseline values, but the increase in BIS value was more signifi-cant in CP group than nCP group. Moreover, BIS values increased significantly 2 minutes after intubation in CP group compared with nCP group. CONCLUSIONS: It was concluded that the application of CP in combination with laryngoscopy and intubation increases the BIS values, which show the inadequacy of anesthesia and hypnosis during the routine induction of anesthesia.

Effect of controlled hyperventilation on the pressor response to laryngoscopy and tracheal intubation.

Pressor response to laryngoscopy and tracheal intubation includes rises in blood pressure and heart rate. This response may be harmful in the presence of cerebral or myocardial diseases. Although different preventive measures have been developed the choice of the agent or method has not been defined clearly. Hypocapnia is commonly used in anesthesia practice for different indications. It depresses the cardiovascular system and lowers the cardiac output. This study investigated the effect of controlled hyperventilation on the pressor response to laryngoscopy and tracheal intubation in three groups of healthy adult patients with different levels of end tidal CO2. The blood pressure and heart rate were recorded during induction of general anesthesia before and after laryngoscopy and tracheal intubation. The pressor responses to laryngoscopy and tracheal intubation in hypocapnic and normocapnic groups were comparable. Moderate degrees of controlled hyperventilation caused relatively more fluctuation in blood pressure during induction of anesthesia. It can be concluded that controlled hyperventilation has no beneficial effect upon the pressor response to laryngoscopy and tracheal intubation.