Vital Capacity Breath Technique Research Articles

Comparison of Pre-oxygenation with Single Vital Capacity Breath Technique and Tidal Volume Breathing Technique for Adult Patients Undergoing General Anaesthesia

Background: Pre-oxygenation before induction of general anaesthesia is widely used for enhancing oxygen reserves and preventing hypoxia. Several techniques for pre-oxygenation have been described. This study was designed to compare the PaO2 and ETO2 with single vital capacity breath technique (SVCB) and tidal volume breathing technique (TVB) for adult patients undergoing general anaesthesia.
 Methods: Fifty patients were pre-oxygenated with both techniques - first SVCB then TVB separated by five minutes of breathing room air or till ETO2 & PaO2 values reached baseline values (whichever was later). ABG samples & ETO2 readings were taken before pre-oxygenation & every thirty seconds for three minutes in both techniques.
 Results: Pre-test, mean PaO2 and ETO2 values of both techniques (SVCB and TVB) were similar. In SVCB technique, the mean PaO2 (mmHg) and ETO2 (%) significantly increased at 30 seconds (p ≤ 0.001) from 95.26 and 17.14 (pre-test time) to 304.34 and 92.48 respectively. In TVB technique, an exponential increase was noted. The mean PaO2 (mmHg) and ETO2(%) significantly increased at 180 seconds (p ≤ 0.001) from 96.26 and 16.26 (pre-test time) to 305.64 and 93.08 respectively. Peak values of oxygenation in both groups were similar but achieved at different time points.
 Conclusion: SVCB technique achieves high oxygenation rapidly but is not sustained thus can be used for rapid sequence induction though not recommended for difficult airway scenarios. TVB technique also achieves high oxygenation but steadily. TVB may be used for induction, including, rapid sequence induction but after 3-5 minutes of pre-oxygenation.

A comparative study of sevoflurane induction using continuous tidal volume breaths versus three vital capacity breaths technique in adult patients undergoing elective surgical procedures under general anaesthesia

Introduction: Previous studies have shown stable cardiovascular parameters and minimal airway irritation with sevoflurane induction in adults. Also, time taken for induction is comparable to intravenous drugs. The authors planned to conduct a randomized, control study to compare the effect of continuous tidal volume breaths versus three vital capacity breaths for sevoflurane induction on time taken for induction, haemodynamic parameters and intubating conditions in adult patients undergoing elective surgery under general anaesthesia. Materials and Methods: Sixty patients planned to undergo elective surgical procedures under general anaesthesia were included in study. Patients were divided randomly using sealed opaque envelope method in group 1 and group 2 of thirty patients each. Group 1 patients received continuous tidal volume breath and group 2 patients received three vital capacity breaths. The statistical analysis was done using IBM SPSS Statistics Software Version 15.0. The independent samples Student t-test was used to determine the differences in basic clinical characteristics, mean Arterial Pressure, heart Rate, and intubation time between the two groups. Quantitative data were evaluated by chi square test. Any p value less than 0.05 was considered as significant. Result: Variation in heart rate between two groups was statistically significant at 1 min. (p=0.04), 2 min. (p=0.01) and 3 min. (p=0.004) after start of induction. The time taken for loss of consciousness was significantly less in vital capacity induction group. (p Conclusion: Heart rate and mean arterial pressure remain stable during sevoflurane induction in adult patients using three vital capacity breath or tidal volume breath technique. Intubating conditions are better and time taken to lose consciousness is less with vital capacity breaths. Keywords: Sevoflurane, Adult, Tidal volume, Vital capacity.

Comparison of intravenous induction with propofol versus inhalation induction with sevoflurane: A prospective randomized controlled study

Background: Propofol is widely used for the induction of anesthesia. Sevoflurane, a popular inhalational induction agent for pediatric patients, may also be used in adults with needle phobias. Aims and Objectives: This study was done to compare the two popular induction agents, namely, propofol and sevoflurane. The speed of achieving the conditions ideal for intubation, in the background of the synergistic action of sevoflurane with vecuronium, the non-depolarizing muscle relaxant was also studied. Materials and Methods: In this prospective randomized controlled study, female patients between 20 and 65 years of age belonging to the American Society of Anaesthesiologists Grade I and II who underwent elective surgeries for breast cancer under general anesthesia were allocated randomly into two groups. Group 1 patients received propofol as the induction agent and in Group 2 sevoflurane was used as the induction agent. Induction with vital capacity breath technique using 8% sevoflurane was compared with standard induction with propofol. Results: It was found that propofol caused a greater drop in blood pressure (BP), although the time for induction was marginally lower (insignificant) with propofol. Sevoflurane potentiated the effect of vecuronium. One case in the sevoflurane group developed laryngospasm and hence was excluded from the study. Three patients in the propofol group had pain on injection. One patient from each group had abnormal transient groaning sound on induction and two patients from sevoflurane group had coughing on induction. Conclusion: Propofol and sevoflurane are equally fast in inducing anesthesia. Sevoflurane potentiates the action of non-depolarizing muscle relaxants when compared to propofol during induction and may be considered as a better option for patients in whom fall in BP is unlikely to be tolerated even for a short period.

Hemodynamic Responses and intubating conditions in laryngeal mask airway insertion a comparative study of propofol versus sevoflurane

Background: LMA is an effective alternative to the endotracheal tube for securing the airway in short surgical procedures. Propofol is a widely used anaesthetic agent for the insertion of Laryngeal Mask Airway. Sevoflurane is a volatile anaesthetic agent, which combines rapid, smooth inhalational induction of anaesthesia with rapid recovery, making it ideal for day care anaesthesia. Objective: To study if the use of sevoflurane can be used as an alternative to IV propofol for laryngeal mask airway insertion. Primary objective: Hemodynamic responses during Laryngeal mask insertion. Secondary objective: Intubating conditions during laryngeal mask airway insertion. Study design: A Randomized control trial. Methods: 100 adults were allocated by randomization into two groups of 50 each; group P (Propofol) and group S (Sevoflurane). Patients in group P were induced with 2.5mg/kg intravenous propofol with 50%O2 & 50%N2O and in group S with 8% sevoflurane in 50%O2 & 50% N2O vital capacity breath technique. Laryngeal mask airway was inserted after adequate jaw relaxation was attained and hemodynamic responses like pulse rate, blood pressure were monitored. The grading of conditions for laryngeal mask airway insertion and number of attempts were noted. All the data collected was analysed statistically. Results: We observed that more number of attempts were required for LMA insertion in Group S (14.0%) compared to Group P (0.0%) which is statistically significant with P=0.012. Heart rate at one minute and 2 minutes after LMA insertion showed a fall with Propofol which was statistically significant as compared to Sevoflurane. There is a significant difference of fall in mean arterial blood pressure in group P during induction, one minute, 2 minutes and 5 minutes when compared between the two groups. Sevoflurane took longer time for induction and LMA insertion compared to Propofol which is statistically significant. Moderate patient movement were noticed in 5 patients of group S and no patient movement were noticed in group P and is statistically significant (P – 0.022). Quality of insertion with propofol was excellent in all patients. With sevoflurane quality of insertion ranged from excellent to satisfactory. Conclusion: Sevoflurane is associated with good hemodynamic stability but intubating conditions provided with propofol is superior. Prolonged time for jaw relaxation with sevoflurane when compared to propofol may delay laryngeal mask airway insertion. Quality of insertion with propofol was excellent in all patients. With sevoflurane quality of insertion ranged from excellent to satisfactory.

Anesthesia with 1.5 minimum alveolar concentration sevoflurane is not altered by physostigmine as measured by bispectral and clinical indices

Study Objective To evaluate the effect of physostigmine on 1.5% sevoflurane anesthesia and recovery. Design Prospective, randomized, double-blinded study. Setting Operating room of a university-affiliated, metropolitan hospital (Aretaieion Hospital and St Savas Hospital). Patients Forty female American Society of Anesthesiologists physical status I and II patients scheduled for breast biopsy. Interventions Patients were randomly assigned in physostigmine (PHYSO) and normal-saline (NS) group. Anesthesia was induced with sevoflurane 8% using a vital capacity breath technique, and rocuronium 0.6 mg/kg was given to facilitate Laryngeal Mask Airway (LMA) No. 4 insertion. Anesthesia was maintained with end-tidal sevoflurane 1.5 minimum alveolar concentration (MAC; 3% end-tidal concentration) throughout the procedure. Measurements After skin closure and under steady-state sevoflurane anesthesia 1.5 MAC, heart rate, blood pressure, and Bispectral Index (BIS) were recorded. Immediately after, the PHYSO group received intravenous 2 mg of physostigmine, whereas the NS group received equal volume of normal saline. Bispectral Index and hemodynamic measurements were recorded 5, 8, and 10 minutes after treatment. Anesthesia was then discontinued and the LMA was removed. Zero, 15, and 30 minutes after LMA removal, patients were evaluated for orientation, sedation, sitting ability, and the “picking up matches” test, as well as for nausea and vomiting. Main Results No difference was found in BIS (29 ± 4, 32 ± 6, 31 ± 6, 30 ± 7, 84 ± 11 in the PHYSO group vs 29 ± 6, 30 ± 6, 30 ± 5, 31 ± 5, 86 ± 7 in the NS group), hemodynamic parameters, or recovery parameters between the 2 groups at any time. No nausea or vomiting was observed in either group. Conclusions Physostigmine did not influence BIS values or early recovery when administered to patients anesthetized with 1.5 MAC sevoflurane anesthesia.

Characteristics of Inhalational Induction with Sevoflurane in Adults

Background: If an inhalation agent has an odor that causes airway irritation and cardiovascular instability, it is important that inhalation induction is performed rapidly and smoothly. So, we studied characteristics of inhalational induction in healthy adults using high inspired concentrations of sevoflurane. Methods: Fifty-three patients, 19 to 59 years old, received 6 vol% sevoflurane in 66 vol%/28 vol% by face mask for five minutes until endotracheal intubation. Participants exhaled to residual volume and took vital capacity breaths of the gas mixture, thereafter ventilation was manually assisted. Subsequently we recorded the number of breaths before apnea, time to loss of consciousness, the loss of lid-lash reflex, eyeball deviation, the time until BIS reduced to 45, degree of jaw relaxation, and vital signs. After endotracheal intubation without muscle relaxant, ease of intubation and vital signs were observed. Results: Apnea developed after an average three time vital capacity breaths, time to unconciousness was less than one minute. The mean times to loss of lid-lash reflex was 69.0 8.2 seconds, to eyeball deviation 85.7 2 22.2 seconds, and to pupil convergenece 239.5 31.4 seconds. There was no case of increased secretion or laryngospasm during mask ventilation. The BIS score was significantly lowered after inhalational induction, and the time to a BIS 19.7 seconds. Mean blood pressures before and after intubation were 75.0 mmHg, and 104.6 mmHg, and heart rates before and after intubation were 77.0 beats/min and 109.8 beats/min, respectively. Conclusions: The speed of the induction of anesthesia to loss of lid lash reflex in healthy adults approaches that of intravenous induction techniques. No untoward airway responses were noted using the vital capacity breath technique. Healthy adults were successfully intubated with sevoflurane without muscle relaxant.

Single vital capacity breath for preoxygenation.

The report investigates, in awake patients before induction of anesthesia, the effect of preoxygenation by the single vital capacity breath technique following forced exhalation on the mean arterial PO2 (PaO2). In 10 adult patients undergoing elective surgery, the mean PaO2 values achieved 30 sec after preoxygenation by the single vital capacity breath technique was compared with the mean PaO2 values achieved by preoxygenation by the traditional tidal volume breathing for three minutes. Each patient served as her/his own control. The mean PaO2 following the single vital capacity breath technique was higher (295 +/- 67 mmHg) than that achieved by the traditional tidal volume breathing technique at 30 sec and 60 sec, and was not significantly different from that achieved by the traditional technique after three minutes (307 +/- 70 mmHg). The single vital capacity breath technique following forced exhalation can rapidly provide adequate preoxygenation within 30 sec.

Effect of Sevoflurane Concentration on Inhalation Induction of Anaesthesia in the Elderly

We have conducted a randomized, double-blind comparison of 4% and 8% sevoflurane for induction of anaesthesia in unpremedicated patients aged more than 60 yr. Sevoflurane was inhaled in 50% nitrous oxide using a vital capacity breath technique, and mean, systolic and diastolic arterial pressures and heart rate were monitored continuously using a Finapres cuff. In the 8% sevoflurane group, time to successful laryngeal mask insertion was significantly shorter (mean 168 (SD 34) s vs 226 (62) s; P

Comparison of Sevoflurane with Propofol for Laryngeal Mask Airway Insertion in Adults

We performed a prospective, randomized, controlled trial to compare the quality and ease of laryngeal mask airway (LMA) insertion after either rapid inhaled sevoflurane or IV propofol induction of anesthesia.Seventy-six unpremedicated ASA physical status I or II patients were anesthetized with either a single vital capacity breath of sevoflurane 8% or IV propofol 3 mg/kg, which produced equally rapid loss of consciousness (40.5 +/- 13.9 vs 37.7 +/- 9.9 s; P > 0.05). The LMA was inserted more rapidly in patients in the propofol group (74 +/- 29 vs 127 +/- 35 s; P < 0.01) and required fewer attempts (1.2 vs 1.6; P < 0.05) than the sevoflurane group. There was a greater incidence of initially impossible mouth opening in the sevoflurane group (45% vs 21%; P < 0.05). Once mouth opening was possible, the degree of attenuation of laryngeal reflexes was similar. The overall incidence of complications related to LMA insertion, especially apnea (32% vs 0%; P < 0.01), was more frequent in the propofol group (82% vs 26%; P < 0.01). There were four failures of LMA insertion in the propofol group and none in the sevoflurane group. Both groups had stable hemodynamic profiles and good patient satisfaction. We conclude that sevoflurane vital capacity breath induction compares favorably with IV propofol induction for LMA insertion in adults. However, prolonged jaw tightness after the sevoflurane induction of anesthesia may delay LMA insertion. Implications: In this randomized, controlled trial, we compared the ease of insertion of the laryngeal mask airway in adults after induction of anesthesia with either a sevoflurane vital capacity breath technique or propofol IV. We conclude that sevoflurane compares favorably with propofol, although prolonged jaw tightness may delay laryngeal mask airway insertion. (Anesth Analg 1999;88:908-12)

Effect of sevoflurane concentration on inhalation induction of anaesthesia in the elderly

We have conducted a randomized, double-blind comparison of 4% and 8% sevoflurane for induction of anaesthesia in unpremedicated patients aged more than 60 yr. Sevoflurane was inhaled in 50% nitrous oxide using a vital capacity breath technique, and mean, systolic and diastolic arterial pressures and heart rate were monitored continuously using a Finapres cuff. In the 8% sevoflurane group, time to successful laryngeal mask insertion was significantly shorter (mean 168 (SD 34) s vs 226 (62) s; P < 0.01) and achieved more often at the first attempt than in the 4% sevoflurane group. Arterial pressures were lower in the 8% group, but this was not significant. No patient had apnoea lasting longer than 1 min. A total of 69% of patients described induction as pleasant and 85% would choose to have it again. We conclude that compared with 8% sevoflurane, the use of 4% sevoflurane in the elderly resulted in greater cardiovascular stability but at the cost of prolonged and occasionally unsuccessful induction.

Inhalational induction with isoflurane: the influence of lidocaine pretreatment.

The effect of intravenous lidocaine in reducing the incidence of complicated induction during a single vital capacity breath technique using isoflurane was studied. Forty patients were randomized into two groups to receive either placebo (group A) or intravenous lidocaine 1.5 mg·kg-1 (group B) just prior to induction. Inhalational induction using 2% isoflurane and 66% nitrous oxide in oxygen was then carried out. Patients pretreated with lidocaine had significantly fewer complications during induction of anesthesia. Modest decreases in blood pressure and heart rate were observed in both groups but were clinically insignificant. Intravenous lidocaine pretreatment significantly reduced the incidence of complications during inhalational induction.

A comparison of vital capacity breath and tidal breathing techniques for induction of anaesthesia with high sevoflurane concentrations in nitrous oxide and oxygen

Vital capacity breath and tidal breathing techniques were compared for induction of anaesthesia with 7.5% sevoflurane in nitrous oxide, and oxygen. Thirty five subjects were randomly assigned to a vital capacity breath group (19) or to a tidal breathing group (16). The mean time for induction was faster with vital capacity breath (41 s) than with tidal breathing (52 s, p < 0.05). Some involuntary movements were seen in the tidal breathing group but none in the vital capacity breath group. Coughing was seen in a quarter of the subjects in the tidal breathing group and in one subject of the vital capacity breath group. The vital capacity group showed excellent characteristics: rapid, and pleasant induction without premedication. We conclude that the vital capacity breath technique is necessary for the inhalation induction of anaesthesia; it provides enough overpressure to allow the subject to pass reliably and rapidly through the initial stages of excitement.

Pre-Oxygenation and the Parturient Patient

Summary The effects of pre-oxygenation were studied by continuous expired oxygen analysis in twenty pregnant patients and ten nonpregnant controls. The Magill system and a demand valve breathing system were both studied with tidal and vital capacity breathing. Rapid pre-oxygenation was possible with the demand valve system but the technique was associated with air leaks around the mask. Vital capacity breathing with the Magill system was inefficient in practice because of rebreathing and air leaks, and the recently proposed four vital capacity breath technique provided suboptimal alveolar oxygenation in pregnant subjects. Oxygenation in pregnant subjects was significantly faster than in nonpregnant controls and was achieved after just 2 minutes of tidal breathing from a standard Magill system with a prefilled reservoir. Care was necessary to ensure a gas-tight seal around the facemask.

Comparison of Halothane and Isoflurane for Rapid Anesthetic Induction

To study the hypothesis that isoflurane will induce anesthesia faster than halothane when given by a single vital capacity breath technique, we studied 20 ASA I and II adults who breathed approximately 4.5 MAC equivalents of either vapor. The patients, randomly assigned to receive either agent, were fully preoxygenated and monitored for cardiovascular, respiratory, and EEG parameters. All subjects were premedicated with 5 micrograms/kg fentanyl IV 5 min before induction. Time to loss of consciousness was significantly longer with halothane than with isoflurane (86 +/- 4 vs 38 +/- 2 sec, respectively) although there were no clinically remarkable differences in cardiovascular or respiratory variables. Patients given halothane had a greater excitatory phase on EEG, whereas those given isoflurane had low frequency predominance. Overall rapid inhalation induction was well-received by all patients and was significantly faster with isoflurane.

Pre-oxygenation and the parturient patient.

The effects of pre-oxygenation were studied by continuous expired oxygen analysis in twenty pregnant patients and ten nonpregnant controls. The Magill system and a demand valve breathing system were both studied with tidal and vital capacity breathing. Rapid pre-oxygenation was possible with the demand valve system but the technique was associated with air leaks around the mask. Vital capacity breathing with the Magill system was inefficient in practice because of rebreathing and air leaks, and the recently proposed four vital capacity breath technique provided suboptimal alveolar oxygenation in pregnant subjects. Oxygenation in pregnant subjects was significantly faster than in nonpregnant controls and was achieved after just 2 minutes of tidal breathing from a standard Magill system with a prefilled reservoir. Care was necessary to ensure a gas-tight seal around the facemask.