Dept Of Anesthesiology & Critical Care, University Of Pennsylvania School Of Medicine

Maternal Mortality and Anesthesia

Lawsuits against physicians insured by the Doctor’s Company for anesthesia related maternal arrests associated with labor and delivery were recently reviewed Ann Lofsky, M.D.  The series included 22 cases that occurred between 1998 and 2006.  Ten out of the 22 died, including 3 who were declared brain dead and removed from ventilators.  Eleven suffered some degree of anoxic brain damage.  Only one had no apparent post arrest neurologic residual deficit.  Respiratory arrest after epidural or spinal block was the most common event (13 of the 22 of which 11 had a high neuraxial blockade and apnea and 2 had a caesarian section under spinal anesthesia with arrest after i.v. sedation).   Of note was the fact that none of the patients were attached to a maternal monitor with audible alarms at the time of the arrest which may have delayed recognition of a developing problem.  Epidural Catheters: Eight of these thirteen patients arrested in labor rooms following attempted insertion and dosing of epidural catheters to relieve labor pains.  Of these, 7 had subsequent evidence of unintentional subarachnoid blocks.  All eight arrests occurred within the first 30 min of initial catheter placement.  In four cases the anesthesiologist was not in the room at the time of the arrest.  Seven of the 8 cases involved transfer of a mother in respiratory or circulatory arrest from the labor room to the operating room for a STAT section due to fetal distress.  In four of these cases there were documented delays in ventilation of the mother for reasons including failure to notice maternal arrest, desire for more optimal intubating conditions present in OR, difficulty locating an Ambu-bag, or anesthesia provider not present.  In the one patient who did not have neurologic residual, the patient was placed supine in the delivery room by the anesthesiologist and was ventilated by bag and mask as soon as ventilation appeared inadequate.  Blood pressure was supported by i.v. fluids and the caesarian section was done in the delivery room.  Spinal Anesthesia:  Five cases occurred in patients for elective caesarean section.  In two cases intravenous benzodiazepine or opioid were given after delivery.  In one case there was an arrest immediately after the spinal was placed.  The arrest was thought to have been secondary to pre-eclampsia and volume depletion.  In two other cases there was an apparent high spinal with delay in recognition or resuscitation.  Maternal hemorrhage leading to arrest occurred in 7 cases.  Three occurred after normal spontaneous vaginal delivery and 4 after caesarean section.  Common problems included difficulty in recognizing the presence of hemorrhage, delays in obtaining blood, waiting for typed and crossed blood, inadequate venous access, and not getting help.  In this total series of arrests 17 pts had regional blocks and five had general anesthetics.  One of the general anesthetics involved a difficult intubation and loss of airway.  There was no evidence of aspiration of gastric contents in the series.  Conclusions: 1) Since all of the respiratory arrest after labor epidurals in this series occurred within 30 minutes after catheter insertion increased monitoring and/or the continuous presence of the anesthesiologist might have prevented or allowed earlier recognition of a developing problem.  2) Having audible alarms for pulse oximetry might have called attention to a problem earlier.  3) Airway equipment including oxygen needs to be present and immediately available in the room when regional anesthetics are placed.  4) Ventilation and oxygenation of the mother should be established before transporting the mother to another location.  5) Massive hemorrhage on labor and delivery is rare, but the incidence may be increasing given the increased rate of repeat Cesarean sections and an associated rise in placenta previa and acreta.  One New York hospital established an obstetric rapid response team and demonstrated a reduction in maternal death despite an increase in their cases of major obstetrical hemorrhage.  This is a link to the article as it appeared in the Anesthesia Patient Safety Foundation Newsletter of 2007

(http://www.apsf.org/resource_center/newsletter/2007/summer/02_maternal_arrest.htm ).

          The Doctors Company is a very large and respected physician owned company specializing in physician malpractice insurance.

          Dr Arkoosh comments on the above: 1) Isn't it remarkable how far we have come with decreasing the risks from management of the maternal airway.  This is due to heightened awareness of the problem and implemented strategies to prepare for and respond to challenging maternal airways.  We need to apply this same level of diligence to potential complications from neuraxial blocks.  2) It has been shown over and over that we underestimate the amount of maternal blood loss.  Data from the UK consistently finds that we under resuscitate this patient population.  I would point out that it is not always possible to observe all of the maternal blood loss and that we should generally error on the side of giving what we think might be "too much".

 

Valerie Arkoosh M.D., MPH is Professor of Clinical Anesthesiology and Critical Care and Professor of Clinical Obstetrics and Gynecology at the University of Pennyslvania.

 

David S. Smith, M.D., Ph.D.

Medical legal cases of interest - OB anesthesia

The ASA closed claimed analysis program recently reported on injuries associated with regional anesthesia (Lee et al: Anesthesiology 2004;101:143-52).  Davies JM (ASA Newsletter 2004;68 http://www.asahq.org/Newsletters/2004/06_04/davies06_04.html) has discussed recent trends in obstetrical anesthesia closed claims..  Davies notes that about 12% of the 310 claims in the 1990s were related to maternal death, and 6% to maternal brain damage in which the patient survived.  They emphasized that a large proportion of the obstetrical claims were for relatively minor injuries such as headache, nerve damage, emotional distress, or back pain to name a few.

Despite the conclusions that complications from neuraxial anesthesia may have relatively smaller costs associated with them, a recent search using Factiva and Lexus Nexus has revealed a number of very expensive settlements as well as cases with successful defenses. As with my last attempt at reviewing recent anesthesia related medical malpractice cases (Clinical Advisory August 2007) my sources are limited and the information provided is also limited.  My search does not in anyway provide information about the total number of settlements and my lack of legal training may make some of my interpretations suspect.  The settlement awards in the case of verdicts for the plaintiffs are most likely shared among more than one defendant and may not represent the final settlement.

Elective C – section under spinal anesthesia resulted in death to the mother with a settlement of $6.7 million.  The claim was made that there was an intravascular injection of lidocaine (Goldsmith v Lechiara, trial date January 2004)

            C-section for fetal distress under spinal anesthesia resulted in anoxic brain injury to the mother with a settlement of $6.6 million (names withheld, settlement approval date October 2005).  According to the information provided “The plaintiff was brought to the operating room where the defendant anesthesiologist injected spinal anesthesia …The anesthesiologist’s records indicated that during the procedure, the plaintiff’s upper extremities became uniformly mottled and that the oxygen saturation monitor on the plaintiff’s finger stopped functioning.  The obstetric surgeons noted that the blood in the surgical field was dark, and the anesthesiologist was questioned about the oxygen saturation of the patient.  The anesthesiologist determined that the patient was not breathing, cardiopulmonary resuscitation was commenced, and a code was called.”

            C-section under epidural anesthesia resulted in claim of post cardiac arrest short-term memory loss, emotional labiality and inability to resume her career.  Complicating the management of the patient was the fact that the patient was a dwarf and placement of the epidural was difficult.  The patient developed breathing difficulties after injection of a single dose of local anesthetic through the epidural needle.  The verdict for the defense was facilitated by the ability to demonstrate that the injection of the epidural and the subsequent resuscitation were within the standard of care.  The defense was also able to present alternative explanations for the patient’s neurologic changes (case i.d. withheld, April 2007).

            C-section under spinal anesthesia resulted in claim of mild hypoxic ischemic encephalopathy with resulting short term memory loss.  There was a verdict for the defendant anesthesiologist (Johntee v Jefferson, trial date February 2006).

            C-section under spinal anesthesia resulted in a claim of spinal nerve injury.  There was a verdict for the defendant anesthesiologist (Schwander v. Esser, trial date April 2004).

Of greater interest are two papers that allow the beginning of an estimate of incidence.  Mhyre investigated maternal deaths in Michigan between 1985-2003 (Anesthesiology 2007;106:1096-104) and noted that of 855 reported pregnancy associated deaths, 8 were found to be anesthesia related and 7 were found to be anesthesia contributing.  Of particular interest was the finding that five of the deaths were related to hypoventilation or airway obstruction during emergence, extubation or recovery.  With respect to regional anesthesia, a 32 year old became apneic and suffered cardiac arrest in the PACU after a c-section using spinal anesthesia, a 42 year old who received a spinal anesthetic for c-section and PCA for post op pain arrested 9 hours post surgery, a 50 year old developed a high spinal and cardiac arrest after an epidural test dose given for c-section, and a 42 year old experienced bradycardia and cardiac arrest after administration of a spinal anesthetic for elective c-section.  Of particular importance from the point of view of risk was cardiac arrest and failed resuscitation in a 29 year old who underwent vacuum aspiration of an undesired first trimester pregnancy under deep sedation and was found pulseless and apneic 25 minutes after arrival in the PACU; attempts at resuscitation failed.

Auroy et al (Anesthesiology 2002;97:1274-80) provides results showing that in France during a 10 month period extending from August 1, 1998 – May 31, 1999, 487 participant anesthesiologists reported their complications after administering 5,640 spinal anesthetics.  In this study there was 1 cardiac arrest, no episodes of respiratory failure, no seizures, 2 episodes of peripheral neuropathy, and no episodes of cauda equine syndrome, central neurologic events such as stroke, meningitis or deaths.

Though serious complications such as death, brain injury, cardiac arrest after regional anesthesia in the obstetrical population appears to be uncommon, severe injury can occur as indicated both by the ASA closed claimed study, the maternal death in Michiganstudy and my recent review of malpractice cases going to trial.

David S. Smith M.D., Ph.D.

Airway management for C sections

Airway management for Cesarean section is a common question on the American Anesthesiology Written Board or In training exam.  Valerie Arkoosh, M.D., reviews the approach to this complex clinical challenge. Emergency C/S: Difficult Airway.  Anesthesia-related maternal mortality is the 7th leading cause of maternal morality in the U.S.  The ASA Closed Claims Analysis found that 23% of the damaging events associated with obstetrical general anesthesia were due to difficult tracheal intubation and esophageal intubation.  Other problems included aspiration of gastric contents, inadequate ventilation and respiratory failure.  Incidence of failed intubation in OB is estimated at 1 in 280.  Compounding the difficulty is the urgency of many situations and the needs of the fetus.

            Relevant anatomic and physiologic changes during pregnancy include: upper airway edema (changes in voice often a clue to this), breast enlargement, excessive weight gain, cephalad displacement of diaphragm, decreased functional residual capacity, increased oxygen consumption, increased risk of aspiration (incompetence of the gastroesophageal junction due to shift in the position of the stomach, progesterone-mediated decrease in gastroesophageal smooth muscle tone, prolonged gastric emptying during labor), and edema associated with preeclampsia.

            Prevention: Timely evaluation of the airway prior to an emergency allows for placement of epidural in high-risk parturients.  The vast majority of urgent or emergent cesarean sections can be anticipated with regular evaluation of laboring patients.  Ongoing communication between the obstetric and anesthesia teams is essential for prevention of disasters.

            Airway Assessment: Mallampati Class (may advance during pregnancy and during labor), atlanto-occipital joint extension (normal = 35 degrees), thyromental distance (>6.5 cm = reassuring, <6 cm = likely difficult/impossible), and ability to protrude the mandible anterior to the front of the upper incisors are used.  There is a risk of difficult laryngoscopy in pregnant women (>90%) if the following combination is present: Mallampati III or IV, protruding maxillary incisors, short neck and receding mandible.

            Difficult airway identified, regional anesthesia contraindicated/impossible, now what? Cesarean Section – non-emergent: Administer aspiration prophylaxis and drying agent such as glycopyrrolate, consider awake oral fiberoptic intubation, awake look via direct laryngoscopy or the use of other specialized scopes depending upon your skill and availability of equipment.  Position: Patient should be “ramped” with head, upper body and shoulders elevated above the chest.  Equipment: Smaller ETTs should be utilized due to airway edema.  The recommend size is 6.5 or smaller.  Avoid nasal airways if possible due to increased risk of significant epistaxis.

            Cesarean section – emergent, unanticipated difficult airway: Administer aspiration prophylaxis as time allows (Bicitra usually possible), position carefully.  If the first attempt at intubation fails a more experienced person should make the next attempt.  A call for additional help (including surgical airway experts), smaller ETT, different blade, gum elastic bougie, repositioning should all be considered.  DO NOT make more than three attempts at direct laryngoscopy as this may increase upper airway edema and make ventilation impossible.  Mask ventilation will be required in between each attempt at intubation due to the rapid oxygen desaturation experienced by pregnant women.  Consider use of an oral airway and jaw thrust maneuvers to facilitate ventilation.  After three attempts, mask ventilation with cricoid pressure should be initiated.  If fetus/mother stable, patient can be ventilated until awake.  If fetus/mother not stable, delivery can proceed with mask ventilation and cricoid.  An LMA  or other airway device may also be placed at this time.  Cricoid pressure will need to be released during LMA placement then re-established.  If mask ventilation is not possible, an LMA should be tried first.  The LMA has a very high success rate in ventilating the obstetric patient.  The Combitube is also an option.  If ventilation proves impossible, transtracheal jet ventilation should be instituted.  A route for exhalation through the mouth or nose must be established to avoid barotrauma.

            Cesarean section – emergent, known difficult airway: Consider regional (spinal or continuous spinal with an epidural catheter).  This may be faster than any other option.  Surgeons may also proceed with local anesthesia (Busby T: Local anesthesia for cesarean section. Am J Obstet Gynecol 1963; 87:399-404).  Consider emergency surgical airway.  Induction of general anesthesia should be the last resort and emergency airway equipment and surgical support should be immediately available.  The ASA guidelines for Difficult Airway Management apply also to the parturient and need to be followed. Additional reference Crit Care Med 2005; 33[Suppl.]:S259-S268.

            Valerie Arkoosh, M.D., MPH is Professor of Clinical Anesthesiology and Critical Care at the University of Pennsylvania.  Her subspeciality interest is Obstetrical Anesthesia